The role of exogenous insulin in the complex of hepatic lipidosis and ketosis associated with insulin resistance phenomenon in postpartum dairy cattle

Genetic evaluations and genome-wide association studies for specific digital dermatitis diagnoses in dairy cows considering genotype × housing system interactions

The present study aimed to use detailed phenotyping for the claw disorder digital dermatitis (DD) considering specific DD stages in 2 housing systems (conventional cubicle barns [CON] and compost-bedded pack barns [CBPB]) to infer possible genotype × housing system interactions. The DD stages included 2,980 observations for the 3 traits DD-sick, DD-acute, and DD-chronic from 1,311 Holstein-Friesian and 399 Fleckvieh-Simmental cows. Selection of the 5 CBPB and 5 CON herds was based on a specific protocol to achieve a high level of herd similarity with regard to climate, feeding, milking system, and location, but with pronounced housing-system differences. Five other farms had a "mixed system" with 2 subherds, one representing CBPB and the other one CON. The CBPB system was represented by 899 cows (1,530 observations), and 811 cows (1,450 observations) represented the CON system. The average disease prevalence was 20.47% for DD-sick, 13.88% for DD-acute, and 5.34% for DD-chronic, with a higher prevalence in CON than in CBPB. After quality control of 50K genotypes, 38,495 SNPs from 926 cows remained for the ongoing genomic analyses. Genetic parameters for DD-sick, DD-acute, and DD-chronic were estimated by applying single-step approaches for single-trait repeatability animal models considering the whole dataset, and separately for the CON and CBPB subsets. Genetic correlations between same DD traits from different housing systems, and between DD-sick, DD-chronic, and DD-acute, were estimated via bivariate animal models. Heritabilities based on the whole dataset were 0.16 for DD-sick, 0.14 for DD-acute, and 0.11 for DD-chronic. A slight increase of heritabilities and genetic variances was observed in CON compared with the "well-being" CBPB system, indicating a stronger genetic differentiation of diseases in a more challenging environment. Genetic correlations between same DD traits recorded in CON or CBPB were close to 0.80, disproving obvious genotype × housing system interactions. Genetic correlations among DD-sick, DD-acute and DD-chronic ranged from 0.58 to 0.81. SNP main effects and SNP × housing system interaction effects were estimated simultaneously via GWAS, considering only the phenotypes from genotyped cows. Ongoing annotations of potential candidate genes focused on chromosomal segments 100 kb upstream and downstream from the significantly associated candidate SNP. GWAS for main effects indicated heterogeneous Manhattan plots especially for DD-acute and DD-chronic, indicating particularities in disease pathogenesis. Nevertheless, a few shared annotated potential candidate genes, that is, METTL25, AFF3, PRKG1, and TENM4 for DD-sick and DD-acute, were identified. These genes have direct or indirect effects on disease resistance or immunology. For the SNP × housing system interaction, the annotated genes ASXL1 and NOL4L on BTA 13 were relevant for DD-sick and DD-acute. Overall, the very similar genetic parameters for the same traits in different environments and negligible genotype × housing system interactions indicate only minor effects on genetic evaluations for DD due to housing-system particularities.

Alterations in the gut microbiota and its metabolites contribute to metabolic maladaptation in dairy cows during the development of hyperketonemia

Metabolic maladaptation in dairy cows after calving can lead to long-term elevation of ketones, such as β-hydroxybutyrate (BHB), representing the condition known as hyperketonemia, which greatly influences the health and production performance of cows during the lactation period. Although the gut microbiota is known to alter in dairy cows with hyperketonemia, the association of microbial metabolites with development of hyperketonemia remains unknown. In this study, we performed a multi-omics analysis to investigate the associations between fecal microbial community, fecal/plasma metabolites, and serum markers in hyperketonemic dairy cows during the transition period. Dynamic changes in the abundance of the phyla Verrucomicrobiota and Proteobacteria were detected in the gut microbiota of dairy cows, representing an adaptation to enhanced lipolysis and abnormal glucose metabolism after calving. Random forest and univariate analyses indicated that Frisingicoccus is a key bacterial genus in the gut of cows during the development of hyperketonemia, and its abundance was positively correlated with circulating branched-chain amino acid levels and the ketogenesis pathway. Taurodeoxycholic acid, belonging to the microbial metabolite, was strongly correlated with an increase in blood BHB level, and the levels of other secondary bile acid in the feces and plasma were altered in dairy cows prior to the diagnosis of hyperketonemia, which link the gut microbiota and hyperketonemia. Our results suggest that alterations in the gut microbiota and its metabolites contribute to excessive lipolysis and insulin insensitivity during the development of hyperketonemia, providing fundamental knowledge about manipulation of gut microbiome to improve metabolic adaptability in transition dairy cows.IMPORTANCEAccumulating evidence is pointing to an important association between gut microbiota-derived metabolites and metabolic disorders in humans and animals; however, this association in dairy cows from late gestation to early lactation is poorly understood. To address this gap, we integrated longitudinal gut microbial (feces) and metabolic (feces and plasma) profiles to characterize the phenotypic differences between healthy and hyperketonemic dairy cows from late gestation to early lactation. Our results demonstrate that cows underwent excessive lipid mobilization and insulin insensitivity before hyperketonemia was evident. The bile acids are functional readouts that link gut microbiota and host phenotypes in the development of hyperketonemia. Thus, this work provides new insight into the mechanisms involved in metabolic adaptation during the transition period to adjust to the high energy and metabolic demands after calving and during lactation, which can offer new strategies for livestock management involving intervention of the gut microbiome to facilitate metabolic adaptation.

Association of vitamin D status with redox balance and insulin resistance and its predicting ability for subclinical pregnancy toxemia in pregnant sheep

The study aimed to evaluate the role of vitamin D on redox balance, insulin resistance and its predicting value for subclinical pregnancy toxemia (SPT) in pregnant ewes. At four weeks pre-lambing, fifteen healthy pregnant ewes were divided into two groups, ewes with sufficient vitamin D (25-hydroxy-vitamin D (25VitD) (SVD, n = 9) and ewes with insufficient 25VitD (ISVD, n = 6). Blood samples were collected at 4 weeks pre-lambing using modified frequently sampled intravenous glucose tolerance test for the estimation of various metabolites. The baseline glucose, insulin, non-esterified fatty acid (NEFA), fructosamine, beta-hydroxy butyric acid (β-BHA), calcium, phosphorus concentration and total oxidant status (TOS) did not differ significantly between the two groups, however, total antioxidant capacity (TAC) was significantly (p = 0.031) low in ISVD ewes. Area under the curve for glucose, insulin, elimination rate of glucose and peak insulin also did not differ significantly between the two groups. Correlation analysis revealed, positive association of 25VitD with fructosamine, calcium and TAC, and negative correlation with NEFA and TOS. Subsequent blood sampling at 2 weeks pre-lambing and at lambing showed significant difference in NEFA (p = 0.001), β-HBA (p = 0.001), and fructosamine(p = 0.012) between the two groups. A significant time x group interaction was observed in NEFA (p = 0.019), β-HBA (p = 0.031), and fructosamine (p = 0.026) concentration. The NEFA concentrations were increased and fructosamine decreased at 2 weeks pre-lambing and at lambing along with significantly increased β-HBA at 2 weeks pre-lambing in ISVD compared to SVD. Taking 0.8 mmol/L β-HBA as the cut off limit for SPT, ISVD ewes had higher odds of developing SPT two weeks prior to lambing (OD 16.00; p = 0.042) and at lambing (OD 10; p = 0.077). This study concludes that 25VitD significantly influence redox balance and energy profile and serves as a valuable predictor for SPT in pregnant sheep.

Comparison of nutrient supply from the dam to fetus and placental development in Holstein and Japanese black cows pregnant with similar or different fetus breeds

A lower nutrient supply from Holstein (HOL) dams to beef fetuses than HOL fetuses has been demonstrated, but the underlying factors remain unclear. We investigated maternal, umbilical vein, and calf blood glucose and amino acid concentrations at calving, along with placental development at term, in HOL dams with similar fetuses (HOL-HOL, n = 12), F1 crosses (HOL × Japanese Black [JB]; HOL-F1, n = 4), JB fetuses (HOL-JB, n = 7), and JB dams with similar fetuses (JB-JB, n = 11). Calf birth weight, total cotyledonary weight, and surface area were greater in HOL-HOL compared to JB-JB or HOL-JB (P < 0.05), whereas those of HOL-F1 were similar. Blood amino acid concentrations in the umbilical veins and calves were similar among HOL-HOL, HOL-F1, and HOL-JB. Calf blood glucose concentrations were lower in HOL-F1 than HOL-HOL (P < 0.05), despite similar maternal blood glucose levels. HOL-JB exhibited higher maternal, umbilical vein, and calf blood glucose concentrations than JB-JB (P < 0.05). Therefore, the glucose supply to the fetus may be inhibited in HOL-F1 due to maternal-fetal breed differences. Higher maternal blood glucose concentrations in HOL-JB may result in elevated fetal glucose exposure, potentially affecting postnatal growth and metabolism.

Metabolic Profiling in Ruminant Diagnostics

A herd-based approach and interpretative perspective is necessary in using metabolic profile testing in contrast to individual animal disease diagnostics. Metabolic profile testing requires formulating a question to be answered, followed by the appropriate selection of animals for testing. A range of blood analytes and nutrients can be determined with newer biomarkers being developed. Sample collection and handling and herd-based reference criteria adjusted to time relative to parturition are critical for interpretation. The objective of this article is to review the concepts and practical applications of metabolic profile testing in ruminants.

Feeding rumen-protected lysine altered immune and metabolic biomarkers in dairy cows during the transition period

This experiment was conducted to determine the effects of feeding rumen-protected lysine (RPL; AjiPro-L Generation 3, Ajinomoto Health and Nutrition North America Inc.) from -26 ± 4.6 d prepartum (0.54% RPL of dietary dry matter intake) to 28 d postpartum (0.39% RPL of dietary dry matter intake) on immunometabolic status and liver composition in dairy cows. Seventy-five multiparous Holstein cows, blocked by parity, previous 305-d mature-equivalent milk production, expected calving date, and body condition score during the far-off dry period were assigned to 1 of 4 dietary treatments in a randomized, complete block design with a 2 × 2 factorial arrangement of treatments. Treatments prepartum consisted of total mixed ration top dressed with RPL (PRE-L) or without RPL (PRE-C), and postpartum treatments consisted of total mixed ration top dressed PRE-L prepartum and postpartum, PRE-L prepartum and PRE-C postpartum, PRE-C prepartum and PRE-L postpartum, and PRE-C prepartum and postpartum in 300 g of molasses. Blood samples were taken on -7 ± 0.5, 0 ± 0.5, 7 ± 0.9, 14 ± 0.9, and 28 ± 0.5 d relative to calving. Whole blood samples were taken on -14 ± 0.5, -7 ± 0.5, 7 ± 0.9, and 14 ± 0.9 d relative to calving for oxidative burst and phagocytic capacity of monocytes and neutrophils. Liver samples were collected via a biopsy on -12 ± 4.95 and 13 ± 2.62 d relative to calving and analyzed for liver composition (triacylglyceride and carnitine concentrations), mRNA expression of hepatic genes, and protein abundance. Protein abundance was calculated by normalizing intensity bands for a specific protein with glyceraldehyde-3-phosphate dehydrogenase. Concentrations of haptoglobin and glutathione peroxidase activity in plasma were lower at d 0 for cows in PRE-L (102 µg/mL and 339 nmol/min per mL, respectively) compared with cows in PRE-C (165 µg/mL and 405 nmol/min per mL, respectively). Oxidative burst capacity in monocytes tended to be greater on d 7 postpartum for cows in PRE-L (65.6%) than cows in PRE-C (57.5%). Additionally, feeding RPL altered the mRNA expression in liver tissue prepartum [decreased INSR (insulin receptor), CPT1A (carnitine palmitoyltransferase 1A), and IL1B (interleukin 1 β)] and postpartum [increased IL8 (interleukin 8), EHMT2 (euchromatic histone lysine methyltransferase 2), TSPO (translocator protein), and SLC3A2 (solute carrier family 3 member 2); and decreased SLC7A1 (solute carrier family 7 member 1), SOD1 (superoxide dismutase 1), and SAA3 (serum amyloid A 3)] compared with cows not consuming RPL]. Additionally, cows in the PRE-C prepartum and PRE-L postpartum treatment tended to have greater protein abundance of mTOR postpartum compared with the PRE-C prepartum and postpartum treatment. Protein abundance of SLC7A7 (solute carrier family 7 member 7) pre- and postpartum tended to be greater and BBOX1 (gamma-butyrobetaine dioxygenase 1) tended to be less when RPL was consumed prepartum. In conclusion, cows that consumed RPL during the transition period had molecular changes related to liver composition, enhanced liver function indicated by greater total protein and albumin concentrations in plasma, and improved immune status indicated by decreased haptoglobin, glutathione peroxidase activity, and immune related mRNA expression.

Invited review: Assessment of body condition score and body fat reserves in relation to insulin sensitivity and metabolic phenotyping in dairy cows

The purpose of this article is to review body condition scoring and the role of body fat reserves in relation to insulin sensitivity and metabolic phenotyping. This article summarizes body condition scoring assessment methods and the differences between subcutaneous and visceral fat depots in dairy cows. The mass of subcutaneous and visceral adipose tissue (AT) changes significantly during the transition period; however, metabolism and intensity of lipolysis differ between subcutaneous and visceral AT depots of dairy cows. The majority of studies on AT have focused on subcutaneous AT, and few have explored visceral AT using noninvasive methods. In this systematic review, we summarize the relationship between body fat reserves and insulin sensitivity and integrate omics research (e.g., metabolomics, proteomics, lipidomics) for metabolic phenotyping of cows, particularly overconditioned cows. Several studies have shown that AT insulin resistance develops during the prepartum period, especially in overconditioned cows. We discuss the role of AT lipolysis, fatty acid oxidation, mitochondrial function, acylcarnitines, and lipid insulin antagonists, including ceramide and glycerophospholipids, in cows with different body condition scoring. Nonoptimal body conditions (under- or overconditioned cows) exhibit marked abnormalities in metabolic and endocrine function. Overall, reducing the number of cows with nonoptimal body conditions in herds seems to be the most practical solution to improve profitability, and dairy farmers should adjust their management practices accordingly.

Nuciferine Ameliorates Nonesterified Fatty Acid-Induced Bovine Mammary Epithelial Cell Lipid Accumulation, Apoptosis, and Impaired Migration via Activating LKB1/AMPK Signaling Pathway

High blood concentrations of nonesterified fatty acids (NEFAs) provoke various metabolic disorders and are associated with mammary tissue injury and decreased milk production in dairy cows. Nuciferine, an alkaloid found in Nelumbo nucifera leaves, has great potential for correcting lipid metabolism derangements and lipotoxicity. In this study, we evaluated the lipotoxicity induced by excessive NEFA in bovine mammary epithelial cells (bMECs) and investigated whether nuciferine alleviates NEFA-induced lipotoxicity and the underlying molecular mechanisms. We found that excessive NEFA (1.2 and 2.4 mM) induced lipid accumulation, apoptosis, and migration ability impairment in bMECs, whereas nuciferine could ameliorate these disarrangements, as indicated by decreasing triglyceride content, protein abundance of SREBP-1c, cytoplasmic cytochrome c, and cleaved caspase-3 and increasing protein abundance of PPARα and migration ability. Moreover, nuciferine could reverse NEFA-induced LKB1/AMPK signaling inhibition, and the protective effect of nuciferine on lipotoxicity caused by NEFA was abrogated by AMPK inhibitor dorsomorphin. Furthermore, transfection with LKB1 siRNA (si-LKB1) largely abolished the activation effect of nuciferine on AMPK. Overall, nuciferine can protect bMECs from excessive NEFA-induced lipid accumulation, apoptosis, and impaired migration by activating LKB1/AMPK signaling pathway.

The effects of maternal supplementation of rumen-protected lysine during the close-up dry period on newborn metabolism and growth in Holstein calves

This study aimed to evaluate the effects of rumen-protected lysine (RPL) supplementation during the close-up period on blood metabolites and calf growth. Forty multiparous Holstein dams were selected based on parity, body condition score, and expected calving date, and randomly assigned to a group: with RPL (n = 22) or without (control [CON], n = 18). RPL dams were supplied daily with 80 g of RPL from Day 21 before the expected calving date to parturition. Blood samples were obtained from the dams before the start of supplementation, 1 week before calving, and immediately after calving, and from calves immediately after birth and weekly until 8 weeks of age. Body weight measurements were performed immediately after birth in all calves and at weekly intervals until 8 weeks of age in female calves. No significant difference was observed in serum metabolite levels and plasma amino acid concentrations between the RPL and CON dams before supplementation, whereas plasma lysine concentrations tended to be higher in RPL dams immediately after calving (p = 0.07). Serum total protein levels (p < 0.05) were higher, whereas plasma total amino acid, total essential amino acid, total non-essential amino acid, and other amino acid concentrations were lower in the calves of RPL dams than those of CON dams (p < 0.05). There were no significant differences in calf birth weight between the two groups, although female calves of RPL dams (n = 7) had higher serum total protein (p < 0.05) and tended to have greater body weight (p = 0.09) from 1 to 8 weeks of age than those of CON dams (n = 11). Overall, RPL supplementation during the close-up period may increase placenta-mediated amino acid transfer to the foetus and enhance protein synthesis in the calf, leading to improved weight gain during the suckling period.

The Influence of Energy Balance, Lipolysis and Ketogenesis on Metabolic Adaptation in Cows Milked Twice and Three Times Daily

Increasing milk production requires increasing milking frequency (MF) from two times daily (2X) to three (3X) or more. High milk production leads to negative energy balance (NEB) and homeorhesis, characterized by lipolysis, ketogenesis, and endocrinological changes. The relationship among energy balance (EB), lipolysis, and ketogenesis with endocrine and metabolic parameters in blood of cows milked 2X and 3X daily was studied. Holstein Friesian cows milked 2X (n = 45) and 3X (n = 45) were analyzed, with approximately 50% of cows in each group in positive EB (PEB) and 50% in NEB. After determining EB, blood samples were collected from all cows and blood serum was analyzed for non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHB), glucose (GLU), cholesterol (CHOL), triglycerides (TGC), total bilirubin (TBIL), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), calcium (Ca), inorganic phosphate (P), total protein (TPROT), albumin (ALB), urea, insulin (INS), T3, T4, and cortisol (CORT), and the RQUICKIBHB index of insulin resistance was calculated. Cows milked 3X in NEB represent a special cluster that partially overlaps with cows milked 2X in NEB and has no contact points with cows in PEB. Cows milked 3X had higher levels of NEFA, BHB, AST, GGT, TBIL, and CORT and lower levels of GLU, Ca, INS, and T4. Cows milked 3X in NEB had higher levels of NEFA, BHB, AST, GGT, TBIL, and CORT and lower levels of GLU, CHOL, TGC, TPROT, P, INS, RQUICKIBHB, and T3 compared with cows milked 2X in NEB and cows in PEB. In cows milked 3X, lipolysis and ketogenesis were much more prominent, and EB levels were lower, implying a pronounced shift in homeorhesis. Metabolic and endocrinology parameters were determined mainly by the values of EB, NEFA, and BHB in cows milked 3X in NEB compared with other categories of cows. The results confirm the peculiarity of metabolic adaptation in cows with increased MF, characterized not only by differences in the concentration of metabolites but also in their interactions.

Randomized controlled trial assessing the impact of a combined treatment of insulin glargine and propylene glycol on the resolution of hyperketonemia and milk production in postpartum dairy cows

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Cows were enrolled when simultaneously hyperketonemic and hypoglycemic.

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Treatment with propylene glycol and insulin glargine did not improve overall time-to-hyperketonemia resolution.

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Treatment with propylene glycol and insulin glargine improved overall milk production after enrollment.

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For both outcomes, there was a clear effect of treatment in primiparous cows but none in older cows.

Multiple treatments for hyperketonemia have been studied, and although propylene glycol has been the most constantly reported as successful in mitigating the effects of this condition, a recent study showed that a subpopulation of cows affected by hyperketonemia and hypoglycemia could benefit from a combined treatment of propylene glycol and insulin glargine. The objective of the present study was to assess the effect of this combination on the time-to-hyperketonemia resolution, and on milk production following the initial treatment. A randomized controlled trial was conducted on 2 commercial farms on which postpartum exams were conducted twice a week. Cows naturally affected by both hyperketonemia [β-hydroxybutyrate (BHB) ≥ 1.4 mmol/L] and hypoglycemia (glucose <2.2 mmol/L) were enrolled and randomly assigned to receive 2 mL of placebo (physiological saline) subcutaneously (PBO), or to receive 2 mL of insulin glargine (200 IU) subcutaneously (INS). Cows in both groups also received 300 g of propylene glycol orally for 3 d. Time-to-hyperketonemia resolution (return to BHB <1.4 mmol/L) and daily milk production following the initial treatment were compared between groups using Cox proportional hazard and mixed linear regression models, respectively. A total of 248 cows between 1 and 30 d in milk (median = 16) were enrolled in the trial from January 2018 to February 2022. Cows were of first (32.3%; n = 80/248), second (32.3%; n = 80/248), or third or greater (35.4%; n = 88/248) parity. The overall time-to-hyperketonemia resolution was not different between treatments, but there was a 2-way interaction between treatment group and parity. Primiparous cows had a shorter time-to-resolution in the INS group than in the PBO group; no difference was observed between treatment groups for older cows. The overall milk production of cows in the INS group was 3.4 kg higher than cows in the PBO group during the 14 d after enrollment. There was a 2-way interaction between treatment group and parity. Primiparous cows in the INS group produced 5.3 kg more milk daily than primiparous cows in the PBO group; no effect of treatment was found for older cows. These results suggest that cows affected simultaneously by hyperketonemia and hypoglycemia benefited from a combined treatment of propylene glycol and insulin glargine to improve subsequent milk production and that the effect primarily came from the positive effect in primiparous cows. Time-to-hyperketonemia resolution was also improved in primiparous cows but not in older cows.

Combined biotin, folic acid, and vitamin B12 supplementation given during the transition period to dairy cows: Part I. Effects on lactation performance, energy and protein metabolism, and hormones

Biotin (B₈), folates (B₉), and vitamin B₁₂ (B₁₂) are involved and interrelated in several metabolic reactions related to energy and protein metabolism. We hypothesized that a low supply of one of the latter vitamins during the transition period would impair metabolic status. The purpose of this study was to evaluate the effect of B₈ supplementation on the response of lactation performance and selected energy and protein metabolites and hormones to a combined supplementation of B₉ and B₁₂ given to periparturient dairy cows, from d -21 to 21 relative to calving. A total of 32 multiparous Holstein cows housed in tie stalls were randomly assigned, according to their previous 305-d milk yield, to 8 incomplete blocks of 4 treatments: (1) a 2-mL weekly i.m. injection of saline (0.9% NaCl; B₈-/B₉B₁₂-); (2) 20 mg/d of dietary B₈ (unprotected from ruminal degradation) and 2-mL weekly i.m. injection of 0.9% NaCl (B₈+/B₉B₁₂-); (3) 2.6 g/d of dietary B₉ (unprotected) and 2-mL weekly i.m. injection of 10 mg of B₁₂ (B₈-/B₉B₁₂+); and (4) 20 mg/d of dietary B₈, 2.6 g/d of dietary B₉, and weekly i.m. injection of 10 mg of B₁₂ (B₈+/B₉B₁₂+) in a 2 × 2 factorial arrangement. Milk yield and dry matter intake were obtained daily and milk components weekly. Blood samples were taken weekly from d -21 to calving and 3 times per week from calving to 21 d following parturition. Prepartum plasma concentrations of glucose, insulin, nonesterified fatty acids (NEFA), β-hydroxybutyrate (BHB), and adiponectin were unaffected by treatments. Biotin, B₉, and B₁₂ supplements increased their respective concentrations in plasma and milk. Cows fed the B₈ supplement tended to have lower dry matter intake, but only cows in B₈+/B₉B₁₂- had greater plasma concentrations of NEFA compared with B₈-/B₉B₁₂-. Milk and total solid yields were greater by 13.5 and 13.9%, respectively, for B₈-/B₉B₁₂+ [45.5 (standard error, SE: 1.8) and 5.81 (0.22) kg/d, respectively] compared with B₈-/B₉B₁₂- [40.1 (1.9) and 5.10 (0.23) kg/d, respectively], but these effects were suppressed when combined with the B₈ supplement. Cows in the B₈-/B₉B₁₂+ group had decreased plasma insulin and tended to have increased NEFA concentrations, but postpartum plasma concentrations of glucose, BHB, leptin, and adiponectin were not affected. These cows also mobilized more body fat reserves, as suggested by a tendency to increased plasma NEFA and more milk total solids compared with B₈-/B₉B₁₂- cows. However, plasma concentrations of BHB and adiponectin were similar among treatments. This suggests that the B₉ and B₁₂ supplements enhanced efficiency of energy metabolism in early lactation cows. Folic acid and B₁₂ supplementation increased postpartum plasma Cys and homocysteine concentrations but did not affect plasma Met concentration, suggesting an upregulation of the transsulfuration pathway. In summary, our results showed that, under the current experimental conditions, increasing B₈ supply did not improve responses to the B₉ and B₁₂ supplementation.

Targeting IRE1α and PERK in the endoplasmic reticulum stress pathway attenuates fatty acid-induced insulin resistance in bovine hepatocytes

Endoplasmic reticulum (ER) stress can be induced by various stimuli and triggers the unfolded protein response to activate intracellular signaling pathways that are mediated by 3 ER-resident sensors: inositol requiring protein-1α (IRE1α), PKR-like ER kinase (PERK), and activating transcription factor-6 (ATF6). In nonruminants, ER stress plays a critical role in hepatic insulin resistance. However, whether ER stress plays a role in nonesterified fatty acid (NEFA)-induced hepatic insulin resistance in dairy cows is still unknown. Experiments were conducted using primary bovine hepatocytes isolated from 5 healthy calves (body weight: 30-40 kg; 1 d old). First, hepatocytes were treated with NEFA (1.2 mM) for 0.5, 1, 2, 3, 5, 7, 9, or 12 h. Treatment with NEFA elevated abundance of phosphorylated IRE1α and PERK, and cleavage of ATF6, along with the ER stress-associated genes XBP1, ATF4, and DNAJC3, resulting in both linear and quadratic effects. Furthermore, ER Tracker red staining and transmission electron microscopy results indicated that ER was dilated and degranulated in response to NEFA treatment, suggesting that ER stress was induced by NEFA treatment in bovine hepatocytes. Second, to assess the effect of ER stress on NEFA-induced insulin resistance, hepatocytes were treated with different concentrations of NEFA (0, 0.6, 1.2, or 2.4 mM) for 5 h with or without tauroursodeoxycholic acid (TUDCA, a canonical inhibitor of ER stress). Here, NEFA induced insulin resistance by increasing the abundance of insulin receptor substrate-1 (IRS1) phosphorylation at the inhibitory residue Ser 307 (S307) and decreasing the abundance of phosphorylated protein kinase B (AKT) and glycogen synthase kinase-3β (GSK3β) in a dose-dependent manner. This was accompanied by upregulation of an abundance of gluconeogenic genes [phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6-Pase)]. These detrimental effects of NEFA on insulin signaling could be reversed with TUDCA treatment, indicating a mechanistic link between ER stress and NEFA-induced insulin resistance. In a third experiment, pGPU6/GFP/Neo vectors containing short hairpin RNA targeting IRE1α were used to silence IRE1α transcription, and GSK2656157 (PERK phosphorylation inhibitor) and 4-(2-aminoethyl) benzenesulfonyl fluoride (AEBSF; an inhibitor of ATF6) were used to block PERK and ATF6 branches, respectively. Notably, the silencing of the IRE1α branch improved NEFA-induced insulin resistance by decreasing phosphorylation of IRS1 (S307) and increasing phosphorylation of AKT and GSK3β, and reducing PEPCK and G6-Pase mRNA abundance, which was likely dependent on IRE1α kinase activity. Similarly, blockage of the PERK branch increased phosphorylation of AKT and GSK3β, and reduced PEPCK and G6-Pase mRNA abundance, but had no effect on phosphorylation of IRS1 (S307). However, results showed that inhibition of the ATF6 branch had no effects on phosphorylation of IRS1, AKT, and GSK3β, and instead found increasing PEPCK and G6-Pase mRNA abundance. Taken together, data in the present study found that impeding IRE1α and PERK signaling might aid in relieving hepatic insulin resistance. However, the more detailed mechanisms of how IRE1α and PERK signaling contribute to hepatic insulin resistance in dairy cows remain to be determined.

Short communication: A comparison between two glucose measurement methods in beef steers during a glucose tolerance test

Glucose tolerance tests (GTT) are commonly performed in beef cattle to evaluate the glucose-insulin signaling pathway. Blood samples are obtained via a catheter and then transferred back to the laboratory for further analysis. A hand-held glucometer used chute-side can make performing GTT’s and quantifying blood glucose concentration much easier and faster for research purposes. The purpose of this study was to evaluate the agreement between a hand-held electronic glucometer (Precision Xtra; Abbott Diabetes Care Inc., Mississauga, ON, Canada) for chute-side use in beef cattle compared with a colorimetric assay in the laboratory (Stanbio Glucose LiquiColor; Stanbio Laboratory, Boerne, TX, USA). A GTT was performed on 13 Simmental × Angus steers during the growing phase. Blood samples were obtained via a jugular catheter. Glucometer readings were taken immediately after blood was sampled from the jugular with no preservative, and laboratory measurements were conducted on plasma preserved with sodium fluoride. A paired t-test (P = 0.40), Pearson’s correlation (P < 0.001; r = 0.95), Bland-Altman plot, and Lin’s concordance correlation coefficient (LCCC = 0.90) were completed to evaluate the performance of the glucometer relative to the results from the laboratory assay. Based on the results, we conclude that the glucometer is an acceptable method for measuring blood glucose concentration in beef cattle under field conditions.

Adaptive Responses of Thyroid Hormones, Insulin, and Glucose during Pregnancy and Lactation in Dairy Cows

The study examined the effects of different stages of pregnancy and lactation on thyroid, insulin, and glucose responses in dairy cows. In the present study, 30 dairy cows (10 Holstein, 10 Simmental, and 10 Brown) at 30 ± 20 d of lactation were randomly selected and blood samples were collected once every 60 d for one year to measure circulating thyroid stimulating hormone (TSH), total and free triiodothyronines (T3, fT3) and thyroxines (T4, fT4), insulin, and glucose. Pregnant cows showed higher T4 (p = 0.010) and insulin (p = 0.046) concentrations at >180 d than at >60−120 d of pregnancy and in nonpregnant cows. Along the lactation phase, circulating T4 concentrations showed a biphasic trend, decreasing from 0−60 d to >60−120 d phase, which showed the lowest values, and then increasing until the end of lactation (>300 d) (p = 0.016). Glucose showed the highest concentrations at the start of lactation (0−120 days) and the lowest values at the end (p = 0.008). The monitoring of thyroid hormones, insulin, and glucose changes represents an important tool to evaluate the anabolic and/or catabolic adaptation in response to functional periods in dairy cows, which can potentially predispose the cows to an excessive negative energy balance and related metabolic issues.

Effect of different dietary regimens at dry-off on performance, metabolism, and immune system in dairy cows

Concentrate withdrawal and feed restriction are commonly used to reduce milk production and to facilitate dry-off, but may impair immune function in dairy cows. We investigated the effect of feed rations providing different amounts of nutrients in combination with feed restriction on performance, endocrine, and metabolic responses, as well as on leukocyte function before and after abrupt dry-off. Forty-three cows were studied from d 12 before until d 6 after dry-off (56 d before scheduled calving). Cows were fed experimental concentrates rich in crude protein (nitrogenic, n = 14), glucogenic precursors (glucogenic, n = 14), or lipids (lipogenic, n = 15). On d 3 before dry-off, total feed allowance was restricted to 50% in half of the animals of each dietary group, whereas feed allowance remained unchanged in the other animals. Performance parameters (milk yield, milk composition, and dry matter intake) were recorded, and daily blood and milk samples were taken and analyzed for various metabolic and endocrine parameters. Additionally, activity and mRNA abundance of several genes in leukocytes were measured at selected time points before and after feed restriction and dry-off, respectively. Feed restriction immediately resulted in a negative energy balance and decreased milk production. Concomitantly, concentrations of nonesterified fatty acids increased, whereas insulin, insulin-like growth factor-1, and glucagon decreased. After dry-off, energy balance turned positive and plasma nonesterified fatty acids decreased. Plasma glucose, insulin, and insulin-like growth factor-1 concentrations increased in all groups after dry-off. Glucose, insulin, and glucagon concentrations in plasma were higher in nonrestricted compared with restricted animals after dry-off. The experimental concentrate types marginally affected the investigated metabolic and endocrine factors, with the exception of elevated milk and plasma urea concentrations in cows fed the nitrogenic concentrate. Chemotactic and phagocytic activity of leukocytes were not affected by diets, feed restriction, or dry-off. Likewise, blood leukocyte mRNA abundance encoding for tumor necrosis factor α (TNF), heat shock protein family A (HSP70), and the glucose transporters (GLUT) 1 and 3 remained unchanged throughout the study period. Overall, the short-term negative energy balance induced by feed restriction was temporarily accompanied by metabolic adaptations, but did not alter the studied factors related to the immune system. Metabolic and endocrine adaptations supporting milk synthesis were continued during the first days after dry-off despite cessation of milking. Thus, the abrupt dry-off resulted in a short-term increase of glucose and triglyceride concentrations, with a delayed endocrine response to re-establish nutrient homeostasis in blood.

Effects of intravenous butaphosphan and cyanocobalamin to late pregnant ewes on the metabolic indices around parturition and weight gain of their lambs after birth

Background

Management and control of metabolic disorders in sheep around parturition is important. and various researchers have suggested different managerial solutions. Butaphosphan and cyanocobalamin are widely used for curing metabolic disorders resulting from poor nutrition, inadequate management or diseases.

Objectives

It was hypothesised that butaphosphan and cyanocobalamin could improve the metabolism of ewes around parturition.

Methods

Twenty‐eight clinically healthy 3‐year‐old pregnant Afshari ewes from 21 days before parturition were enrolled into four equal groups: control (Ctrl), B+C1, B+C2 and B+C3. The Ctrl group only received intravenous normal saline and B+C1, B+C2 and B+C3 ewes, respectively, received an intravenous combination of 10% butaphosphan and 0.005% cyanocobalamin at 2, 4 and 6 ml/ewe, on Days 19–21, 10–12 and 1–3 before parturition. Blood samples were taken from all the ewes on Days 21, 12 and 3 before lambing at parturition day and on days 3, 12 and 21 after parturition. A body condition score of all the ewes was assessed at blood sampling days, and lambs born from the ewes were weighed at birth and every 2 weeks up to 3 months. Serum concentrations of glucose, cortisol, non‐esterified fatty acids, beta‐hydroxy butyric acid, triglyceride, cholesterol, high‐, low‐ and very‐low‐density lipoproteins, aspartate aminotransferase and alanine aminotransferase were measured.

Results

This drug combination decreased circulating glucose, cortisol, lipid profile and hepatic enzymes via dose‐dependent manner, 6 ml of this drug compound/ewe was more potent than 4 and 2 ml/ewe. The lambs’ weight from mothers receiving 6 ml of this combination was significantly higher than those of the others.

Conclusions

It may be suggested that the intravenous administration of 6 ml/ewe of this combination for 3 consecutive days in three states before parturition had prophylactic effects on metabolic disorders of ewes and enhanced the lambs weight gain after birth.

Physiological adaptations in early-lactation cows result in differential responses to calcium perturbation relative to nonlactating, nonpregnant cows

The peripartal cow experiences a rapid change in calcium metabolism at the onset of lactation. Research has focused on understanding how mammary-derived factors, such as serotonin (5HT) and parathyroid hormone like hormone (PTHLH), aid in coordinating these calcemic adaptations to lactation. Therefore, the aim of our study was to determine how induced subclinical hypocalcemia influences physiological responses, specifically the 5HT-PTHLH-Ca axis, in lactating and nonlactating dairy cows to elucidate the potential contribution of the mammary gland. Twelve nonlactating, nonpregnant (NL) multiparous Holstein cows and 12 early-lactation (EL) multiparous Holstein cows received either (1) a continuous 24-h intravenous solution of 0.9% NaCl or (2) 5% ethylene glycol tetraacetic acid (EGTA) solution in 0.9% NaCl (n = 6 EL, n = 6 NL per treatment) with the aim of maintaining blood ionized calcium (iCa) less than 1.0 mM. Mammary gland biopsies were taken immediately after and 48 h after termination of infusion. Blood was sampled hourly during infusion and 4, 8, 12, 24, 48, and 72 h after termination of infusion. Infusion of EGTA successfully decreased blood iCa concentrations. However, EL EGTA-infused cows required increased rates of EGTA infusion to maintain iCa below 1.0 mM. Circulating and mammary serotonin concentrations were increased in EL relative to NL cows, with no difference as a result of EGTA infusion. Mammary PTHLH expression was increased in EL cows, with highest expression observed in EL EGTA-infused cows. Collectively, these data demonstrate the robust adaptations EL cows have to maintain Ca homeostasis and the supporting roles 5HT and PTHLH may play.

Methionine supplementation during a hydrogen peroxide challenge alters components of insulin signaling and antioxidant proteins in subcutaneous adipose explants from dairy cows

Enhanced postruminal supply of methionine (Met) during the peripartal period alters protein abundance of insulin, AA, and antioxidant signaling pathways in subcutaneous adipose tissue (SAT). Whether SAT is directly responsive to supply of Met and can induce molecular alterations is unknown. Our objective was to examine whether enhanced Met supply during an oxidative stress challenge in vitro alters insulin, AA, inflammation, and antioxidant signaling-related protein networks. Four late-lactation Holstein cows (average 27.0 kg of milk per day) were used for SAT collection. Tissue was incubated in duplicate for 4 h in a humidified incubator with 5% CO₂ at 37°C according to the following experimental design: control medium with an "ideal" profile of essential AA (CTR; Lys:Met 2.9:1), CTR plus 100 μM H₂O₂ (HP), or CTR with greater Met supply plus 100 μM H₂O₂ (HPMET; Lys:Met 2.5:1). Molecular targets associated with insulin signaling, lipolysis, antioxidant nuclear factor, erythroid 2 like 2 (NFE2L2), inflammation, and AA metabolism were determined through reverse-transcription quantitative PCR and western blotting. Data were analyzed using the MIXED procedure of SAS 9.4 (SAS Institute Inc.). Among proteins associated with insulin signaling, compared with CTR, HP led to lower abundance of phosphorylated AKT serine/threonine kinase (p-AKT) and solute carrier family 2 member 4 (SLC2A4; insulin-induced glucose transporter). Although incubation with HPMET restored abundance of SLC2A4 to levels in the CTR and upregulated abundance of fatty acid synthase (FASN) and phosphorylated 5'-prime-AMP-activated protein kinase (p-AMPK), it did not alter p-AKT, which remained similar to HP. Among proteins associated with AA signaling, compared with CTR, challenge with HP led to lower abundance of phosphorylated mechanistic target of rapamycin (p-MTOR), and HPMET did not restore abundance to CTR levels. Among inflammation-related targets studied, incubation with HPMET led to greater protein abundance of nuclear factor kappa B subunit p65 (NFKB-RELA). The response in NFKB observed with HPMET was associated with a marked upregulation of the antioxidant transcription regulator NFE2L2 and the antioxidant enzyme glutathione peroxidase 1 (GPX1). No effects of treatment were detected for mRNA abundance of proinflammatory cytokines or antioxidant enzymes, underscoring the importance of post-transcriptional regulation. Overall, data indicated that short-term challenge with H₂O₂ was particularly effective in reducing insulin and AA signaling. Although a greater supply of Met had little effect on those pathways, it seemed to restore the protein abundance of the insulin-induced glucose transporter. Overall, the concomitant upregulation of key inflammation and antioxidant signaling proteins when a greater level of Met was supplemented to oxidant-challenged SAT highlighted the potential role of this AA in regulating the inflammatory response and oxidant status. Further studies should be conducted to assess the role of postruminal supply of Met and other AA in the regulation of immune, antioxidant, and metabolic systems in peripartal cow adipose tissue.

Surrogate Indexes of Insulin Resistance in Dairy Goats: Transitional Variation in Subclinical Hyperketonemia

Background: Dairy goats are highly susceptible to subclinical hyperketonemia (SCHK) during the transition period. This study aimed to compare the variation in metabolic parameters and surrogate indexes of insulin resistance (sIR) between goats with SCHK and clinically healthy (HEAL) goats during the transition period. Methods: Twenty Guanzhong dairy goats were assorted to HEAL (n = 10) and SCHK (n = 10) groups according to the blood β-hydroxybutyrate (BHBA) concentrations. The blood samples were taken from the jugular vein of each goat at −3, −2, −1, 0 (partum), +1, +2, and +3 weeks relative to kidding to analyses GLU and INS. The sIR was calculated from blood metabolic parameters. Results: Compared with the HEAL goats, the insulin concentrations were significantly higher in SCHK goats during the first three weeks postpartum. The QUICKI, revised QUICKI (RQUICKI), and RQUICKI_BHBA were significantly lower in goats with SCHK at 1 week postpartum, while the homeostasis model assessment-IR (HOMA-IR) was significantly higher. Conclusion: Goats with SCHK made more efforts through elevated insulin levels at early lactation than HEAL goats, thereby maintaining the normal glucose concentrations.

Intravenous Administration of Butaphosphan and Cyanocobalamin Combination to Late-Pregnant Dairy Cows Reduces Their Insulin Resistance After Calving

Dairy cows suffer insulin resistance following parturition and lactogenesis. Several researchers attempted to reduce insulin resistance via dietary and parenteral supplementations of different substances to promote metabolic performance of dairy cows. Due to mechanisms of actions of butaphosphan in combination with cyanocobalamin, we hypothesized that this compound may reduce insulin resistance of dairy cows following parturition; hence, the effects of the intravenous administration of butaphosphan and cyanocobalamin to prepartum dairy cows on their insulin resistance after calving were evaluated. Twenty-four multiparous Holstein dairy cows were enrolled 3 weeks prior to parturition and divided into four equal groups, including control (Ctrl) and butaphosphan and cyanocobalamin (B+C) 1, 2, and 3. Ctrl cows received 15 mL of 0.9% NaCl solution and B+C 1, 2, and 3 groups intravenously received 2, 4, and 6 mL/100 kg BW of 10% butaphosphan and 0.005% cyanocobalamin combination over three periods of 3 consecutive days, including 21-19, 12-10, and 3-1 days before calving, respectively. Intravenous glucose tolerance test was performed weekly 1, 2, and 3 weeks after parturition to evaluate the insulin resistance phenomenon. Circulating levels of glucose, insulin, non-esterified fatty acids (NEFA), and beta-hydroxybutyric acid (BHBA) were assessed 1, 2, and 3 weeks after calving. Ctrl cows were the most insulin-resistant group, and B+C1 group was the most insulin-sensitive, followed by B+C2 and B+C3 groups. The NEFA and BHBA levels in the B+C3 group were significantly lower than those in the other groups. In conclusion, intravenous administration of butaphosphan and cyanocobalamin to the late-pregnant dairy cows may reduce their insulin resistance after calving.

Nutritional parameters in the blood of dams during late gestation and immediately after calving, in the umbilical vein at calving, and in the blood of calves immediately following birth in Holstein heifers pregnant with either Holstein or beef breed fetuses

Dairy cattle management lacks consideration of fetal breed, the effect of which on fetal growth and nutrition are unclear. We investigated blood parameters in 12 late-pregnant Holstein heifers with similar (Holstein, n = 5) or different (Japanese Black [n = 4] or F1 cross [n = 3]; Holstein × Japanese Black) fetus breeds and in their umbilical cords and calves. Samples were obtained from dams 1 week before calving (-1 week) and immediately after calving, from the umbilical vein at calving, and from calves immediately after birth. Dams with beef fetuses had higher serum glucose levels (-1 week; p < .05) than those with Holstein fetuses. Plasma total amino acid, total essential amino acid, total nonessential amino acid, and other amino acid concentrations were lower in the umbilical veins of dams with calves of the beef breeds than in those of the Holstein breeds (p < .05). Furthermore, serum glucose and plasma amino acid levels were lower in the beef calves than in the Holstein calves (p < .05). Overall, nutrient supply from dams to beef fetuses was lower than that to Holstein fetuses. Our findings may facilitate feeding management of dairy cattle pregnant with beef breeds for appropriate fetal growth and nutrition.

Role of insulin, insulin sensitivity, and abomasal functions monitors in evaluation of the therapeutic regimen in ketotic dairy cattle using combination therapy with referring to milk yield rates

Background:

Ketosis is one of the most critical metabolic disorders that occur in dairy cows after parturition due to negative energy balance around calving.

Aim:

The study evaluated a specific therapeutic regimen of ketosis in Holstein dairy cattle by using the combination therapy including hormones, corticosteroids, propylene glycol, and vitamin B12 as well as the use of milk yield rates, insulin, insulin sensitivity, and abomasal functions monitors as diagnostic biomarkers for the recovery of ketotic cows either pre-therapy (0 days) or post-therapy (7 and 14 days).

Methods:

This study was conducted on ketotic cattle (n = 20) belonged to different dairy farms in Cairo and Giza governorates, Egypt. The diseased cows were undergoing clinical and biochemical investigations for the estimation of serum insulin. Quantitative Insulin Sensitivity Check Index (RQUICKI) and abomasal functions monitor mainly serum levels of gastrin, pepsinogen, and chloride.

Results:

The milk production rates, cost: benefit analysis ratio, and benefit of the dairy farm in ketotic animals were significantly increased post-treatment. An improvement of insulin sensitivity was stated as serum insulin, and RQUICKI were remarkably increased in post-therapeutic ketotic cows. Monitors of the abomasal function revealed abomasal functions improvement through the significant elevation of blood gastrin and a substantial reduction in serum pepsinogen due to treatment.

Conclusion:

The study revealed high efficacy of the applied therapeutic strategy regime. It led to a high recovery rate and a very low relapse rate for ketosis. An improvement in milk yield rates, insulin sensitivity, and abomasal function monitors was reported. Hypoinsulinaemia was still reported, however, serum insulin was improved.

Impacts of Heat Stress-Induced Oxidative Stress on the Milk Protein Biosynthesis of Dairy Cows

Heat stress (HS) is one of the most important factors posing harm to the economic wellbeing of dairy industries, as it reduces milk yield as well as milk protein content. Recent studies suggest that HS participates in the induction of tissue oxidative stress (OS), as elevated levels of reactive oxygen species (ROS) and mitochondrial dysfunction were observed in dairy cows exposed to hot conditions. The OS induced by HS likely contributes to the reduction in milk protein content, since insulin resistance and apoptosis are promoted by OS and are negatively associated with the synthesis of milk proteins. The apoptosis in the mammary gland directly decreases the amount of mammary epithelial cells, while the insulin resistance affects the regulation of insulin on mTOR pathways. To alleviate OS damages, strategies including antioxidants supplementation have been adopted, but caution needs to be applied as an inappropriate supplement with antioxidants can be harmful. Furthermore, the complete mechanisms by which HS induces OS and OS influences milk protein synthesis are still unclear and further investigation is needed.

Relation of Automated Body Condition Scoring System and Inline Biomarkers (Milk Yield, β-Hydroxybutyrate, Lactate Dehydrogenase and Progesterone in Milk) with Cow's Pregnancy Success

The aim of the current study was to evaluate the relation of automatically determined body condition score (BCS) and inline biomarkers such as β-hydroxybutyrate (BHB), milk yield (MY), lactate dehydrogenase (LDH), and progesterone (mP4) with the pregnancy success of cows. The cows (n = 281) had 2.1 ± 0.1. lactations on average, were 151.6 ± 0.06 days postpartum, and were once tested with "Easy scan" ultrasound (IMV imaging, Scotland) at 30-35 d post-insemination. According to their reproductive status, cows were grouped into two groups: non-pregnant (n = 194 or 69.0% of cows) and pregnant (n = 87 or 31.0% of cows). Data concerning their BCS, mP4, MY, BHB, and LDH were collected each day from the day of insemination for 7 days. The BCS was collected with body condition score camera (DeLaval Inc., Tumba, Sweden); mP4, MY, BHB, and LDH were collected with the fully automated real-time analyzer Herd Navigator™ (Lattec I/S, Hillerød, Denmark) in combination with a DeLaval milking robot (DeLaval Inc., Tumba, Sweden). Of all the biomarkers, three differences between groups were significant. The body condition score (BCS) of the pregnant cows was higher (+0.49 score), the milk yield (MY) was lower (-4.36 kg), and milk progesterone in pregnant cows was (+6.11 ng/mL) higher compared to the group of non-pregnant cows (p < 0.001). The pregnancy status of the cows was associated with their BCS assessment (p < 0.001). We estimated that cows with BCS > 3.2 were 22 times more likely to have reproductive success than cows with BCS ≤ 3.2.

Glucose, insulin, and cortisol concentrations and glucose tolerance test in Holstein cows with inactive ovaries

A total of 60 healthy (the control group) and 30 anestrous Holstein cows with inactive ovaries (the case group) from three dairy farms around Tehran were randomly selected and diagnosed to determine the concentrations of glucose, insulin, and cortisol, and the rate of the insulin resistance disorder in them. Primarily, serum samples were obtained from all animals, and the concentrations of glucose, insulin, and cortisol were measured in a laboratory. Thereupon, the glucose tolerance test (GTT) was implemented. Before the implementation of the GTT, the median of serum glucose levels (62 mg/dl), insulin (7.16 μIU/ml), and cortisol (2.5 μg/dl) was estimated in healthy cows. The median of serum glucose levels (68.5 mg/dl, p = 0.00009) was higher, and serum insulin (6.1 μIU/ml, p = 0.025) and cortisol (1.1 μg/dl, p = 0.00029) levels were lesser in the anestrous cows when estimated simultaneously. After the implementation of GTT, the median of serum glucose concentrations in one (120 mg/dl), two (73.5 mg/dl), and three (63.5 mg/dl) hours after the glucose injection was estimated in healthy cows. The findings also showed that the median of serum glucose levels was lesser in one (100 mg/dl, p = 0.015), similar in two (77.5 mg/dl, p = 0.9), and higher in three (70 mg/dl, p = 0.012) hours after the glucose injection in anestrous cows. In conclusion, higher serum glucose, lesser insulin and cortisol concentrations, and the different correlation between serum glucose and insulin levels before the GTT were detected in anestrous cows. The pattern of glucose changes also differed in anestrous cows after the GTT.

Response to a glucose tolerance test in early-lactation Holstein cows receiving a supplementation of biotin, folic acid, and vitamin B12

The aim of the study was to evaluate glucose and insulin metabolism of cows receiving a supplementation of biotin (B₈), folic acid (B₉), and vitamin B₁₂ (B₁₂) during the transition period. According to a 2 × 2 factorial arrangement, 32 cows were randomly assigned to 9 incomplete blocks according to their previous 305-d milk yield. Within each block, cows were randomly assigned to 1 of the following levels of biotin from -27 to 28 d relative to the parturition: (1) no biotin supplement (B₈-) or (2) 20 mg/d of dietary biotin (B₈+). Within each level of biotin, the cows received either (1) 2-mL weekly intramuscular injections of saline 0.9% NaCl (B₉B₁₂-) or (2) 2.6 g/d of dietary folic acid and 2-mL weekly intramuscular injections of 10 mg of vitamin B₁₂ (B₉B₁₂+). An intravenous glucose tolerance test was performed at 25 d in milk. Baseline plasma glucagon, glucose, and nonesterified fatty acid concentrations did not differ among treatments. For B₉B₁₂+ cows, baseline plasma insulin concentration and maximal glucose concentration after glucose administration were greater when also combined with biotin compared with no biotin combination, whereas there was no effect in B₉B₁₂- cows. There was no treatment effect on time to reach half-maximal glucose and insulin concentrations, glucose positive incremental area under the curve, and glucose and insulin clearance rates. Regarding insulin results, maximal plasma concentration and positive incremental area under the curve were respectively 51 and 74% greater for cows receiving the B₈ supplement than for cows who did not. Moreover, plasma nonesterified fatty acid concentration nadir tended to be reached later for B₈ cows. Insulin peak was reached earlier for cows in the group B₉B₁₂+ than cows in B₉B₁₂-, regardless of B₈ supplementation. Under the current conditions, our results suggested that cows receiving a B₈ supplement had a reduced insulin sensitivity in early lactation. Insulin response was faster for B₉B₁₂+ cows, but this was not translated into further improvements following the glucose administration challenge.

Genetic and nongenetic profiling of milk β-hydroxybutyrate and acetone and their associations with ketosis in Holstein cows

Ketosis is a metabolic disorder of increasing importance in high-yielding dairy cows, but accurate population-wide binary health trait recording is difficult to implement. Against this background, proper Gaussian indicator traits, which can be routinely measured in milk, are needed. Consequently, we focused on the ketone bodies acetone and β-hydroxybutyrate (BHB), measured via Fourier-transform infrared spectroscopy (FTIR) in milk. In the present study, 62,568 Holstein cows from large-scale German co-operator herds were phenotyped for clinical ketosis (KET) according to a veterinarian diagnosis key. A sub-sample of 16,861 cows additionally had first test-day observations for FTIR acetone and BHB. Associations between FTIR acetone and BHB with KET and with test-day traits were studied phenotypically and quantitative genetically. Furthermore, we estimated SNP marker effects for acetone and BHB (application of genome-wide association studies) based on 40,828 SNP markers from 4,384 genotyped cows, and studied potential candidate genes influencing body fat mobilization. Generalized linear mixed models were applied to infer the influence of binary KET on Gaussian-distributed acetone and BHB (definition of an identity link function), and vice versa, such as the influence of acetone and BHB on KET (definition of a logit link function). Additionally, linear models were applied to study associations between BHB, acetone and test-day traits (milk yield, fat percentage, protein percentage, fat-to-protein ratio and somatic cell score) from the first test-day after calving. An increasing KET incidence was statistically significant associated with increasing FTIR acetone and BHB milk concentrations. Acetone and BHB concentrations were positively associated with fat percentage, fat-to-protein ratio and somatic cell score. Bivariate linear animal models were applied to estimate genetic (co)variance components for KET, acetone, BHB and test-day traits within parities 1 to 3, and considering all parities simultaneously in repeatability models. Pedigree-based heritabilities were quite small (i.e., in the range from 0.01 in parity 3 to 0.07 in parity 1 for acetone, and from 0.03-0.04 for BHB). Heritabilites from repeatability models were 0.05 for acetone, and 0.03 for BHB. Genetic correlations between acetone and BHB were moderate to large within parities and considering all parities simultaneously (0.69-0.98). Genetic correlations between acetone and BHB with KET from different parities ranged from 0.71 to 0.99. Genetic correlations between acetone across parities, and between BHB across parities, ranged from 0.55 to 0.66. Genetic correlations between KET, acetone, and BHB with fat-to-protein ratio and with fat percentage were large and positive, but negative with milk yield. In genome-wide association studies, we identified SNP on BTA 4, 10, 11, and 29 significantly influencing acetone, and on BTA 1 and 16 significantly influencing BHB. The identified potential candidate genes NRXN3, ACOXL, BCL2L11, HIBADH, KCNJ1, and PRG4 are involved in lipid and glucose metabolism pathways.

Integrating RNA-Seq with GWAS reveals novel insights into the molecular mechanism underpinning ketosis in cattle

Background

Ketosis is a common metabolic disease during the transition period in dairy cattle, resulting in long-term economic loss to the dairy industry worldwide. While genetic selection of resistance to ketosis has been adopted by many countries, the genetic and biological basis underlying ketosis is poorly understood.

Results

We collected a total of 24 blood samples from 12 Holstein cows, including 4 healthy and 8 ketosis-diagnosed ones, before (2 weeks) and after (5 days) calving, respectively. We then generated RNA-Sequencing (RNA-Seq) data and seven blood biochemical indicators (bio-indicators) from leukocytes and plasma in each of these samples, respectively. By employing a weighted gene co-expression network analysis (WGCNA), we detected that 4 out of 16 gene-modules, which were significantly engaged in lipid metabolism and immune responses, were transcriptionally (FDR < 0.05) correlated with postpartum ketosis and several bio-indicators (e.g., high-density lipoprotein and low-density lipoprotein). By conducting genome-wide association signal (GWAS) enrichment analysis among six common health traits (ketosis, mastitis, displaced abomasum, metritis, hypocalcemia and livability), we found that 4 out of 16 modules were genetically (FDR < 0.05) associated with ketosis, among which three were correlated with postpartum ketosis based on WGCNA. We further identified five candidate genes for ketosis, including GRINA, MAF1, MAFA, C14H8orf82 and RECQL4. Our phenome-wide association analysis (Phe-WAS) demonstrated that human orthologues of these candidate genes were also significantly associated with many metabolic, endocrine, and immune traits in humans. For instance, MAFA, which is involved in insulin secretion, glucose response, and transcriptional regulation, showed a significantly higher association with metabolic and endocrine traits compared to other types of traits in humans.

Conclusions

In summary, our study provides novel insights into the molecular mechanism underlying ketosis in cattle, and highlights that an integrative analysis of omics data and cross-species mapping are promising for illustrating the genetic architecture underpinning complex traits.

Short communication: Effect of glucose infusion dose and stage of lactation on glucose tolerance test kinetics in lactating dairy cows

The objective for this study was to determine the effect of glucose dose and days following peak milk yield on plasma glucose, serum insulin, and plasma nonesterified fatty acids (NEFA) kinetics during an intravenous glucose tolerance test (IVGTT) in lactating dairy cattle. Six lactating Holstein dairy cows (3 primiparous and 3 multiparous) were assigned to 2 squares and received 0.092, 0.15, or 0.3 g of glucose/kg of body weight (BW) during an IVGTT at 74 and 221 d in milk (DIM), representing early (post-peak) lactation and mid lactation, respectively. Treatments were applied in a replicated Latin square design using contiguous 7-d periods within each stage of lactation. Milk production and dry matter intake were determined daily during the first 6 d of each period. The IVGTT was performed on d 7. For the IVGTT, cows were prepared with indwelling catheters in each jugular vein, and blood samples were collected at -15, -10, 5, 10, 15, 20, 30, 45, 60, 90, and 120 min relative to the glucose infusion. Samples were analyzed for plasma glucose, serum insulin, and plasma NEFA concentrations. Increasing the glucose dose during the IVGTT increased plasma glucose area under the curve (AUC), decreased glucose half-life, and increased maximal plasma glucose concentrations in plasma during the IVGTT. Greater glucose dose during the IVGTT elevated serum insulin AUC and increased nadir NEFA concentrations. Maximal plasma glucose concentration during the IVGTT was lower, whereas maximum NEFA concentration, NEFA AUC, and NEFA clearance rate were greater at 74 than at 221 DIM. Only glucose half-life was responsive to stage of lactation × glucose dose effects during the IVGTT, and the decrease in glucose half-life with increasing glucose dose was greater at 74 than at 221 DIM. Glucose AUC was greater and NEFA AUC lower for cows at 74 than at 221 DIM. For the doses tested, a glucose dose greater than 0.092 g/kg of BW resulted in peak blood glucose concentration that exceeded the previously reported renal glucose excretion threshold of 8.3 mM. There is a need for accompanying data to determine if this is the case for the glucose doses evaluated in this experiment. Based on maximal peak glucose concentrations and effects on glucose half-life, we identify 0.092 g of glucose/kg of BW (0.46 g/kg of metabolic body weight) as the preferred dose for the IVGTT for cows at 74 and 221 DIM in this study.

Ketosis an Old Story Under a New Approach

Ketosis, characterized by high concentrations of ketone bodies in the blood, urine, and milk, affects a considerable number of cows immediately after calving. Although much is known about ketosis, dairy cows continue to be affected in every herd world-wide. Cows affected by ketosis are treated with palliative treatments after the disease is diagnosed. This is a very expensive approach and costs the dairy industry extra expenses, contributing to lower profitability of dairy herds. In this review article, we summarize the mainstream view on ketosis, classification of ketosis into three types, current diagnostic approaches to ketosis, and the economic impact of ketosis on dairy farms. Additionally, we discuss the most recent applications of the new ‘omics’ science of metabolomics in studying the etiopathology of ketosis as well as its contribution in identification of novel screening or diagnostic biomarkers of ketosis.

The biochemical and metabolic profiles of dairy cows with mycotoxins-contaminated diets

BACKGROUND

Previous studies on the effects of mycotoxins have solely focused on their biochemical profiles or products in dairy ruminants. Changes in metabolism that occur after exposure to mycotoxins, as well as biochemical changes, have not been explored.

METHODS

We measured the biochemical and metabolic changes in dairy cows after exposure to mycotoxins using biochemical analyses and nuclear magnetic resonance. Twenty-four dairy cows were randomly assigned to three different treatment groups. Control cows received diets with 2 kg uncontaminated cottonseed. Cows in the 50% replacement group received the same diet as the control group, but with 1 kg of uncontaminated cottonseed and 1 kg of cottonseed contaminated with mycotoxins. Cows in the 100% replacement group received the same diet as the control, but with 2 kg contaminated cottonseed.

RESULTS

The results showed that serum γ-glutamyl transpeptidase and total antioxidant capacities were significantly affected by cottonseed contaminated with mycotoxins. There were also significant differences in isovalerate and NH3-N levels, and significant differences in the eight plasma metabolites among the three groups. These metabolites are mainly involved in amino acid metabolism pathways. Therefore, the results suggest that amino acid metabolism pathways may be affected by mycotoxins exposure.

Lipid Catabolism in Starved Yak Is Inhibited by Intravenous Infusion of β-Hydroxybutyrate

Simple Summary

Yak, which is the predominant and semi-domesticated livestock on the Qinghai-Tibet Plateau, suffers severe starvation and body weight reduction in the cold season because of the harsh highland environment. Lipids are important energy sources to starvation animals. β-hydroxybutyrate (BHBA) that is derived from lipid decomposition as the primary ketone body is with the function not only to provide energy for animals as energy materials, but also regulate lipid metabolism as signaling molecular. However, the effects of starvation and BHBA on lipid metabolism and its mechanism are still unclear for ruminant animals. Herein, we investigated the effects of starvation and intravenous infusion of BHBA solution on Yak growth, serum biochemistry, hormones, subcutaneous adipocyte morphology, fatty acid composition, activity of enzymes related to lipid metabolism, and signal pathway. The results showed that starvation promoted lipid catabolism and BHBA infusion up-regulated the mRNA expression of receptor GPR109A in subcutaneous adipose tissue, inhibited the Cyclic adenosine monophosphate(cAMP)/Protein kinase A (PKA)/cAMP-responsive element binding protein (CREB) signaling pathway, and inhibited lipolysis. Our study was beneficial for enriching the nutrition regulation theory of yaks and improving their growth potential.

Abstract

Lipid is the chief energy source for starved animals. β-hydroxybutyrate (BHBA) is the main ketone body produced by lipid decomposition. In Chinese hamster ovary (CHO) cell experiment, it was found that BHBA could be used not only as an energy substance, but also as a ligand of GPR109A for regulating lipid metabolism. However, whether BHBA can regulate lipid metabolism of yaks, and its effective concentration and signal pathway are not clear. This study investigated the effects and mechanism of starvation and BHBA on the lipid metabolism of yak. Eighteen male Jiulong yaks were selected and then randomly divided into three groups: normal feeding group (NG), starvation group (SG), and starvation with BHBA infusion group (SBG). The yaks in the NG group were freely fed during the trial, while the yaks in the SG and SBG groups fasted; from 7th to 9th days of the experiment, the NG and SG were infused continuous with 0.9% normal saline and SBG was infused 1.7 mmol/L BHBA solution respectively. The blood samples were collected on the 0th, 1st, 3rd, 5th, 7th, and 9th day of experiment. The subcutaneous adipose tissue of all the yaks in this study were taken from live bodies after infusion. Serum glucose, lipid metabolites, hormone concentrations, and mRNA and protein expressions of key factors of lipid metabolism and signaling pathway in subcutaneous adipose tissue were measured. The results showed that, as compared with NG, starvation significantly reduced the body weight of yak in SG, and significantly increased the concentration of BHBA in serum and the mRNA expression of PKA and CREB1 in subcutaneous adipose tissue, while the mRNA expression of MEK, PKC, ERK1/2, the area of adipocytes, and the proportion of saturated fatty acid were decreased. Whereas, further increase of BHBA concentration through infusion promoted the mRNA expression of GPR109A receptor in the subcutaneous adipose tissue of SBG, inhibited the mRNA expression of AC and PKA, and decreased the phosphorylation protein abundance of CREB1, and significantly increased the diameter and area of adipocytes. These findings suggest that starvation led to enhanced lipid catabolism in yaks. An increasing BHBA concentration could increase the mRNA expression of GPR109A receptor in subcutaneous adipose tissue and inhibit the cAMP/PKA/CREB signaling pathway and lipid decomposition.

Evaluation of postpartum metabolic and health response in dairy cows with different body condition score during the dry period

This study aimed to evaluate the effects of different pre-calving body conditions on some metabolic indices, health status and reproductive disorders in dairy cows. The study was conducted on a dairy farm in Eastern Slovakia during the pre-partum period (–1 to –10 DIM) and post-partum period (1 to 14 DIM). Total of 84 cows allotted in 3 groups were submitted to clinical examination and body condition score (BCS) evaluation. At the same intervals blood samples were collected for determination of beta-hydroxybutyrate (BHB), non-esterified fatty acids (NEFA), and calcium levels. During the postpartum period the incidence of reproductive diseases, such as metritis, retained placenta, metabolic disorders, such as milk fever, left displacement of abomasum and orthopaedic disorders were recorded. The strongest lipid mobilisation (NEFA elevation), ketone body production, and blood calcium drop were determined in postpartum dairy cows with the highest prepartum body condition score. In conclusion, the dairy cows with different BCS hade a different metabolic response during the postpartum period. The overcondition was connected with stronger lipid mobilisation and calcium drop after calving. Moreover, the higher BCS could contribute to higher incidence of production diseases.

Glucose related endocrine and metabolic responses following bolus intravenous hypertonic dextrose administration in Iranian fat-tailed ewes at different pre and post parturition periods

Providing glucose as primary metabolic fuel for maintenance, foetal growth and milk production may be considered necessary for protection against negative energy balance and metabolic disorders. Five adult Ghezel ewes were selected 4 weeks before their parturition and followed at 2 weeks before, 2 and 4 weeks and 2, 3 and 4 months after parturition. Dextrose 50% was administered at 500 mg/kg, 10 mL/kg/hour, and blood samples were collected from all ewes prior to and 1, 2, 3 and 4 hours after 50% dextrose infusion. Serum levels of glucose, beta-hydroxybutyric acid, non-esterified fatty acids, cholesterol, triglyceride, high, low and very low density lipoproteins, insulin, triiodothyronine, thyroxine, prolactin, cortisol and insulin like growth factor-1 were evaluated. Glucose and insulin were increased significantly and immediately following intravenous dextrose administration at all studied periods. The levels of beta-hydroxybutyric acid and non-esterified fatty acids were significantly decreased following dextrose infusion at all periods. Triiodothyronine was decreased in pregnant ewes and increased in non-pregnant, lactating ones. The significant increasing cortisol patterns were detected at 2 and 4 weeks before and 2 and 4 weeks after parturition following dextrose administrations. The decreasing patterns of insulin like growth factor-1 were seen in all studied periods. Prolactin was significantly increased following dextrose administration at 4 and 2 weeks before and 2 weeks after parturition. Bolus intravenous hypertonic dextrose administration could induce the obvious endocrine and metabolic responses in Ghezel ewes via providing a source of energy and the glucose is an important direct controller of metabolic interactions in Ghezel ewes.

Insulin resistance: Relationship between indices during late gestation in dairy cows and effects on newborn metabolism

To investigate the relationship between insulin resistance indices ["Revised quantitative insulin sensitivity check index" (RQUICKI; RQ), "Revised quantitative insulin sensitivity check index - β-hydroxybutyrate" (RQUICKI_BHB ; RQ_BHB ), and "Homeostasis model assessment-insulin resistance" (HOMA-IR; HR)], and metabolic parameters in dams during late gestation, and their newborn calves. Blood was sampled twice weekly during the experimental period in 30 dry Holstein cows. In calves, blood sampling and body weight measurements were performed immediately after birth, and in 1-week-old male calves, liver and muscle biopsy samples were obtained for determining metabolic factor mRNA levels. RQ and RQ_BHB were negatively correlated with insulin, nonesterified fatty acid, BHB, and albumin and were positively correlated with leptin levels in blood during late gestation (p < .05). RQ, rather than RQ_BHB , reflected metabolism of dams, while stronger positive correlations were present between HR and blood insulin concentrations than other parameters, and calves of dams with high HR had low body weight, and high liver and muscle expression of growth hormone and insulin receptor mRNA (p < .05). RQ and HR of dams during late gestation could serve as indicators of dam metabolism and predictors of metabolism in newborn calves respectively.

Lipid profile of bovine blastocysts exposed to insulin during in vitro oocyte maturation

Insulin is a key hormone with important functions in energy metabolism and is involved in the regulation of reproduction. Hyperinsulinaemia is known to impair fertility (for example, in obese mothers); therefore, we aimed to investigate the impact of elevated insulin concentrations during the sensitive period of oocyte maturation on gene expression and lipid profiles of the bovine Day-8 embryo. Two different insulin concentrations were used during in vitro oocyte maturation (INS10=10µgmL-1 and INS0.1=0.1µgmL-1) in order to observe possible dose-dependent effects or thresholds for hyperinsulinaemia in vitro. By investigating gene expression patterns by an mRNA microarray in combination with lipid profile analysis by desorption electrospray ionisation-mass spectrometry (DESI-MS) of embryos derived from insulin-treated oocytes, we gained further insights regarding molecular responses of embryos to insulin provocation during the first days of development. Lipid metabolism appeared to be influenced on multiple levels according to gene expression results but the profiles collected in positive-ion mode by DESI-MS (showing mostly ubiquinone, cholesteryl esters and triacylglycerols) did not differ significantly from controls. There are parallels in follicular development of ruminants and humans that make this bovine model relevant for comparative research on early human embryonic development during hyperinsulinaemia.

Relationship between insulin, glucose, non-esterified fatty acid and indices of insulin resistance in obese cows during the dry period and early lactation

The aim of this study was to determine to relationship between glucose, insulin, non-esterified fatty acid (NEFA) and indices of insulin resistance in the dry period (DP) and early lactation (EL). The importance of this study was in determining the relation between insulin sensitivity in DP and insulin resistance in EL. A total of 30 normally fed Holstein-Friesian cows with a high body condition score (> 3.75) were included in the study. Blood samples were collected in DP (weeks 5-7 ante partum) and EL (weeks 1-2 post partum). Cows in EL showed higher insulin resistance in comparison to DP due to a lower concentration of glucose and insulin, higher concentration of NEFA, lower value of revised quantitative insulin sensitivity check index and higher values of glucose:insulin and NEFA:insulin ratios (lower pancreas responsivnes to glucose and antilipolytic effect of insulin). Higher concentrations of insulin and glucose in the DP lead to a decrease in their concentrations and an increase in glucose:insulin and NEFA:insulin ratios in the EL. The revised quantitative insulin sensitivity check index in DP negatively correlates with the same index in EL, while positively correlating with the NEFA and NEFA:insulin ratio in EL. The EL revised quantitative insulin sensitivity check index value was influenced by dynamic changes (DP minus EL) in the insulin, NEFA, and glucose concentrations. The relationship between the indicators shows that higher insulin sensitivity in the DP increases resistance in EL in normally fed obese dairy cows.

Prepartum body conditions affect insulin signaling pathways in postpartum adipose tissues in transition dairy cows

Background

Overconditioned dairy cows are susceptible to excessive lipolysis and increased insulin resistance during the transition period. The associations among body fat reserve, insulin resistance, and lipolysis in adipose tissues (AT) remain to be elucidated. Therefore, this study aimed to investigate whether excessive fat reserves influence the insulin signaling pathway in AT postpartum.

Results

Twenty multiparous dairy cows were selected and assigned to one of two groups, according to prepartum body condition score (BCS): Control group (BCS = 3.0-3.5; n = 10) and Overconditioned group (BCS ≥ 4.0; n = 10). Blood samples were collected on days -14, -7, -4, -2, -1, 0, 1, 2, 4, 7, and 14 relative to parturition. Subcutaneous AT were collected on day 2 following parturition for quantitative real-time polymerase chain reaction and western blot analyses. No differences were observed between the two groups in serum glucose, non-esterified fatty acids, β-hydroxybutyric acid, tumor necrosis factor (TNF) α, insulin, or leptin concentrations during the experimental period. Compared with the control cows, the overconditioned cows had lower serum triglyceride levels and higher adiponectin concentrations. In the AT postpartum, insulin receptor mRNA and protein levels were lower in the overconditioned cows than in the control cows, and no differences were found in glucose transporter 4 mRNA. Compared with the control cows, the overconditioned cows had lower mRNA levels of TNFα and higher mRNA levels of peroxisome proliferator-activated receptor gamma (PPARγ) in AT postpartum. The phosphorylated protein kinase B (AKT) content and phosphorylation rate of AKT were increased in the overconditioned cows compared with the control cows, which suggested that the downstream insulin signaling in AT was affected.

Conclusions

In the present study, transition dairy cows with higher BCS did not show more fat mobilization. The changes of insulin signaling pathway in AT postpartum of overconditioned cows may be partly related to the expression of PPARγ and TNFα, and the secretion of adiponectin.

Exogenous β-mannanase supplementation improved immunological and metabolic responses in lactating dairy cows

Exogenous enzymes have been used to improve nutrient utilization in several species of livestock, particularly swine and poultry. In addition, improved immunological and metabolic traits have been reported in nonruminants. The objective of this study was to determine the effects of β-mannanase supplementation on milk yield and composition, and immunological and metabolic responses in lactating Holstein dairy cows. Two weeks after calving, 20 Holstein cows (10 multiparous and 10 primiparous) were blocked by parity and assigned to 1 of 2 diets for 182 d. All cows were housed in the same environment and fed the same basal diet. The basal diet of the treatment group was supplemented with β-mannanase (CTCBio Inc., Seoul, South Korea) at 0.1% of concentrate dry matter. No differences were detected between the control and enzyme supplement groups in milk yield parameters or milk composition. Supplementation of β-mannanase enzyme reduced blood haptoglobin levels in supplemented multiparous cows compared with controls. Furthermore, nonesterified fatty acid concentration levels tended to be lower in cows fed β-mannanase, regardless of parity. Neither immunoglobulin G nor milk somatic cell count was affected by β-mannanase supplementation, regardless of parity. The number of insemination services tended to be lower in cows fed diets supplemented with β-mannanase. Results from this study suggest that supplementation of β-mannanase exogenous enzyme could help to reduce instances of systemic inflammation and decrease fat mobilization in lactating Holstein cows. Multiparous cows are considered susceptible to acute infections and inflammation; thus, the enzyme had a greater effect in multiparous cows.

Association of peripartum plasma insulin concentration with milk production, colostrum insulin levels, and plasma metabolites of Holstein cows

The main objective of this study was to assess associations between plasma insulin concentration around parturition and production in Holstein cows. Primiparous and multiparous cows (n = 267) were enrolled. Blood samples were collected within 12 h after parturition (d 0), and on d 3 and 10 after calving. In addition, blood samples were collected 7 d before (-7 d) the expected date of parturition and colostrum samples were collected within 8 h after parturition from a subset of cows to measure insulin concentration (n = 47). All samples were harvested from 0630 to 1100 h and were used to quantify insulin, nonesterified fatty acids (NEFA), and β-hydroxybutyrate. The plasma concentrations of insulin on d -7 and 0 were not correlated with insulin levels in colostrum. Cows were grouped according to plasma insulin concentration based on the median as low insulin (L-INS) or high insulin (H-INS) on d 0 (median = 0.35 ng/mL; range 0.2 to 1.2), 3 (median = 0.32 ng/mL; range 0.2 to 1.6), and 10 (median = 0.30 ng/mL; range 0.2 to 0.8). We detected that cows in the L-INS group on d 0 (L-INS = 0.57 ± 0.02; H-INS = 0.49 ± 0.02 mmol/L), d 3 (L-INS = 0.56 ± 0.02; H-INS = 0.49 ± 0.02 mmol/L), and d 10 (L-INS = 0.61 ± 0.03; H-INS = 0.55 ± 0.03 mmol/L) had higher NEFA concentrations compared with cows in the H-INS group. Compared with H-INS cows, milk yield was higher for cows classified as L-INS on d 0 (L-INS = 40.75 ± 0.69; H-INS = 38.41 ± 0.64 kg) and d 10 (L-INS = 40.95 ± 0.74; H-INS = 38.66 ± 0.64 kg). Moreover, fat-corrected milk was higher for cows classified as L-INS on d 0 (L-INS = 40.59 ± 2.36; H-INS = 37.73 ± 2.31 kg) and d 10 (L-INS = 41.00 ± 2.42; H-INS = 38.65 ± 2.28 kg) compared with H-INS cows, and energy-corrected milk was higher for L-INS cows compared with H-INS cows regardless of the day (d 0, L-INS = 44.50 ± 0.70 vs. H-INS = 41.67 ± 0.64 kg; d 3, L-INS = 43.65 ± 0.74 vs. H-INS = 40.88 ± 0.72 kg; d 10, L-INS = 44.09 ± 0.73 vs. H-INS = 40.55 ± 0.68 kg). We conclude that low plasma insulin concentration during early lactation is associated with higher milk yield in the long term.

Effects of overconditioning on pancreatic insulin secretory capacity, fat infiltration, and the number and size of islets in dairy cows at the end of the dry period

In the present study, we tested the hypothesis that overconditioning in dairy cows at the end of the dry period leads to infiltration of fat and alterations of the insulin secretory capacity of the pancreas. Pregnant Holstein Friesian dairy cows were selected based on body condition score (BCS) at the start of the dry period. Body condition score varied between cows to have optimal conditioned (2.5 < BCS ≤3.5, n = 5) and overconditioned (3.5 < BCS ≤5, n = 5) cows. All animals underwent an intravenous glucose tolerance test (IVGTT) at an average of 260 d of gestation to measure the pancreatic insulin secretory capacity and assess peripheral insulin sensitivity regarding glucose metabolism. Eight days after the IVGTT, animals were slaughtered. The pancreas was dissected and weighed and tissue samples were taken for histological analysis. Results revealed that overconditioning in dairy cows led to fat infiltration in the pancreas and an increase in size of pancreatic islets expressed relative to the total area of pancreatic tissue. In addition, results revealed a positive correlation between serum fatty acid concentration and peak insulin concentration and area and number of pancreatic islets expressed relative to the total area of pancreatic tissue. The IVGTT revealed that overconditioned animals have a higher insulin secretory capacity of the pancreas, as demonstrated by higher peak insulin concentration, higher acute insulin response to glucose, and higher area under the curve (AUC) for insulin compared with optimal conditioned cows. A higher AUC for glucose during the first 60 min following administration of the glucose bolus in overconditioned cows indicates an insulin-resistant state regarding glucose metabolism. Our results suggest that the pancreas of overconditioned dairy cows at the end of gestation compensates for the concomitantly elevated level of peripheral insulin resistance by greater secretion of insulin.

Chronic Effects of Fusarium Mycotoxins in Rations with or without Increased Concentrate Proportion on the Insulin Sensitivity in Lactating Dairy Cows

The objective of this study was to investigate the effect of long-term exposure to a Fusarium toxin deoxynivalenol (DON, 5 mg/kg DM) on the energy metabolism in lactating cows fed diets with different amounts of concentrate. In Period 1 27 German Holstein cows were assigned to two groups and fed a control or mycotoxin-contaminated diet with 50% concentrate for 11 weeks. In Period 2 each group was further divided and fed either a diet containing 30% or 60% concentrate for 16 weeks. Blood samples were collected in week 0, 4, 8, 15, 21, and 27 for calculation of the Revised Quantitative Insulin Sensitivity Check Index and biopsy samples of skeletal muscle and the liver in w 0, 15, and 27 for analysis by real-time RT-qPCR. The DON-fed groups presented lower insulin sensitivities than controls at week 27. Concomitantly, muscular mRNA expression of insulin receptors and hepatic mRNA expression of glucose transporter 2 and key enzymes for gluconeogenesis and fatty acid metabolism were lower in DON-fed cows compared to the control. The study revealed no consistent evidence that DON effects were modified by dietary concentrate levels. In conclusion, long-term dietary DON intake appears to have mild effects on energy metabolism in lactating dairy cows.

Leistung und Gesundheit von Milchkühen: Bedeutung von Genetik (Ursache) und Management (Wirkung)

Die Milchleistung der Kühe hat sich in den letzten Jahrzehnten aufgrund der Selektion auf Milchmenge, entsprechender Fütterung, veterinärmedizinischer Betreuung und erfolgreichen Managements kontinuierlich erhöht und es ist anzunehmen, dass sich dieser Trend fort - setzen wird. Mit der Milchleistung haben jedoch die Erkrankungsrate zu- und die Nutzungsdauer abgenommen. Umfangreiche Untersuchungen der Tierzucht zeigten genetische Korrelationen zwischen Milchleistung und Erkrankungen wie Ketose/Leberverfettung, Mastitis, Klauenerkrankungen, Metritis (alle entzündlichen Formen) und Abnahme der Fruchtbarkeit auf, deren Pathogenese im Wesentlichen durch die negative Energiebilanz als Folge der Selektion auf hohe Milchleistung kausal bestimmt wird. Die genetische Disposition wird in der Praxis durch Managementfaktoren beeinflusst und diese Wechselwirkungen bestimmen die Inzidenz der Erkrankungen und deren hohe Variation. Es muss also bei der Analyse der Erkrankungen unterschieden werden zwischen der genetischen Disposition (Ursache) und Managementfaktoren (Wirkungen). Eine nachhaltige Verbesserung der Situation schließt die Überprüfung der Zuchtwerte und damit der Selektionskriterien ein.

Effects of niacin supplementation on the insulin resistance in Holstein cows during early lactation

Insulin resistance in early lactation includes low glucose concentration, low insulin release and responsiveness and high lipolysis. Niacin is important antilipolytic agent and leads to increase glucose and insulin concentration. The objectives of this study were to determine the influence of niacin on the insulin resistance in cows during early lactation using the difference of value and regression analysis between blood non-esterified fatty acid (NEFA), glucose and insulin concentrations, revised quantitative insulin sensitivity check index and glucose-to-insulin ratio. Niacin supplementation led to a decrease of NEFA concentration and an increase of glucose and insulin concentrations during the first three weeks after calving. Cows in the niacin group which were more resistant to insulin showed higher concentrations of non-esterified fatty acid in comparison with more sensitive cows from the same group, but still lower than the control. The regression analyses suggest the following characteristics of cows supplemented with niacin in comparison with the control group: the insulin response to glucose was more intense; the antilipolytic effect of insulin was lower; insulin efficiency expressed as glucose-to-insulin ratio increase with a decrease in NEFA. The metabolic changes due to niacin supplementation showed a dual influence on the insulin resistance in dairy cows during early lactation: decreased NEFA concentrations led to a decrease in the insulin resistance (due to an increase in insulin efficiency and insulin sensitivity index), but increased concentrations of insulin and glucose possibly caused an increase in the insulin resistance in dairy cows (due to lower insulin sensitivity index and possibly lower antilipolytic effects of insulin).