A randomized controlled trial investigating the effect of transport duration and age at transport on surplus dairy calves: Part II. Impact on hematological variables

Surplus dairy calves often arrive at veal and dairy-beef rearing facilities with health and blood metabolite level abnormalities, which can affect their welfare and performance, predisposing them to future health challenges. The objective of this randomized controlled trial was to investigate the effects of transport duration and age at the time of transport on blood parameters in surplus dairy calves following 6, 12, or 16 h of continuous road transportation. All surplus calves from 5 commercial dairy farms in Ontario were enrolled and examined daily before transport (n = 175). On the day of transportation, calves were weighed, blood sampled, and randomly assigned to 6, 12, or 16 h of transportation. Blood samples were then collected immediately after transportation, as well as 24, 48, and 72 h thereafter. Serum was analyzed at a provincial diagnostic laboratory for nonesterified fatty acids (NEFA), β-hydroxybutyric acid (BHBA), creatine kinase (CK), cholesterol, and haptoglobin. In addition, blood gas and electrolyte values were also assessed at the time of sample collection. Mixed models with repeated measures were used to assess the effects of transport duration, breed, sex, transfer of passive immunity status, weight before transportation, and age at transportation on blood parameters. Immediately following transportation, NEFA and BHBA were greater for calves transported for 12 h (Δ = 0.22 mmol/L NEFA, 95% CI = 0.15 to 0.30; Δ = 0.04 mmol/L BHBA, 95% CI = 0.02 to 0.06) and 16 h (Δ = 0.35 mmol/L NEFA, 95% CI = 0.27 to 0.42; Δ = 0.10 mmol/L BHBA, 95% CI = 0.08 to 0.11) compared with calves transported for 6 h. Glucose was lower immediately following transportation in calves transported for 16 h compared with 6 h (Δ = -15.54 mg/dL, 95% CI = -21.54 to -9.54). In addition, pH and HCO3- were lower in calves transported for 12 (Δ = -0.09 pH, 95% CI = -0.13 to -0.05; Δ = -1.59 mmol/L HCO3-, 95% CI = -2.61 to -0.56) and 16 h (Δ = -0.07 pH, 95% CI = -0.12 to -0.03; Δ = -1.95 mmol/L HCO3-, 95% CI = -2.95 to -0.95) compared with calves transported for 6 h. Calves transported between 15 and 19 d of age had a higher concentration of cholesterol and CK (Δ = 0.27 mmol/L cholesterol; 37.18 U/L CK) compared with 2- to 6-d-old calves, and calves 12 to 14 d old had greater reduction in HCO3- (Δ = -0.92 mmol/L) compared with 2- to 6-d-old calves. These findings show that transporting calves for long distances results in lower glucose concentration and suboptimal energy status, and that this effect varies based on the calf's age.

Standardized Whole Blood Assay and Bead-Based Cytokine Profiling Reveal Commonalities and Diversity of the Response to Bacteria and TLR Ligands in Cattle

Recent developments in multiplex technologies enable the determination of a large nu\mber of soluble proteins such as cytokines in various biological samples. More than a one-by-one determination of the concentration of immune mediators, they permit the establishment of secretion profiles for a more accurate description of conditions related to infectious diseases or vaccination. Cytokine profiling has recently been made available for bovine species with the development of a Luminex^® technology-based 15-plex assay. Independently from the manufacturer, we evaluated the bovine cytokine/chemokine multiplex assay for limits of detection, recovery rate, and reproducibility. Furthermore, we assessed cytokine secretion in blood samples from 107 cows upon stimulation with heat-killed bacteria and TLR2/4 ligands compared to a null condition. Secretion patterns were analyzed either using the absolute concentration of cytokines or using their relative concentration with respect to the overall secretion level induced by each stimulus. Using Partial Least Square-Discriminant Analysis, we show that the 15-cytokine profile is different under Escherichia coli, Staphylococcus aureus, and Streptococcus uberis conditions, and that IFN-γ, IL-1β, and TNF-α contribute the most to differentiate these conditions. LPS and E. coli induced largely overlapping biological responses, but S. aureus and S. uberis were associated with distinct cytokine profiles than their respective TLR ligands. Finally, results based on adjusted or absolute cytokine levels yielded similar discriminative power, but led to different stimuli-related signatures.

In-line near-infrared analysis of milk coupled with machine learning methods for the daily prediction of blood metabolic profile in dairy cattle

Precision livestock farming technologies are used to monitor animal health and welfare parameters continuously and in real time in order to optimize nutrition and productivity and to detect health issues at an early stage. The possibility of predicting blood metabolites from milk samples obtained during routine milking by means of infrared spectroscopy has become increasingly attractive. We developed, for the first time, prediction equations for a set of blood metabolites using diverse machine learning methods and milk near-infrared spectra collected by the AfiLab instrument. Our dataset was obtained from 385 Holstein Friesian dairy cows. Stacking ensemble and multi-layer feedforward artificial neural network outperformed the other machine learning methods tested, with a reduction in the root mean square error of between 3 and 6% in most blood parameters. We obtained moderate correlations (r) between the observed and predicted phenotypes for γ-glutamyl transferase (r = 0.58), alkaline phosphatase (0.54), haptoglobin (0.66), globulins (0.61), total reactive oxygen metabolites (0.60) and thiol groups (0.57). The AfiLab instrument has strong potential but may not yet be ready to predict the metabolic stress of dairy cows in practice. Further research is needed to find out methods that allow an improvement in accuracy of prediction equations.

Changes in metabolic and hormonal profiles during transition period in dairy cattle - the role of spexin

BACKGROUND

This study aimed to evaluate spexin as a novel blood marker and to describe the relationship of this peptide with selected biochemical metabolites measured during the transition period in dairy cows. Additionally, mRNA expression of the spexin gene as well as spexin receptors - galanin receptor type 2 and galanin receptor type 3, was investigated in several bovine tissues. Blood samples were collected at weekly intervals starting at 21 days before the estimated parturition day until 21 days in milk to determine concentrations of spexin, nonesterified fatty acids, β-hydroxybutyrate acid, total and active ghrelin, progesterone, glucose, insulin, IGF-I, triglycerides, cholesterol, leptin, corticosterone and 17-β-estradiol as well as the activity of aspartate transaminase, alkaline phosphatase and gamma-glutamyl transferase.

RESULTS

Spexin concentration decreased from 21 d before parturition to calving day and next it rose during the first 14 d of lactation. The lowest concentration of spexin was recorded on the calving day and it differed from the mean level of this peptide before parturition as well as postpartum. Moreover, differences were observed between mean spexin concentrations before and after calving. Spexin levels were moderately negatively correlated with NEFA (r = - 0.39) and total ghrelin contents (r = - 0.41), weakly correlated with BHBA (r = - 0.35) while they showed a moderate positive relationship with progesterone concentrations (r = 0.42). Moreover, we detected that mRNA expression of GALR2, GALR3 and SPX is present in various bovine tissues (kidney, bowel, rumen, spinal cord, lung, skeletal muscle, liver, heart, fat and spleen).

CONCLUSION

A negative correlation between spexin concentration and NEFA, BHBA and total ghrelin contents as well as a positive relationship with levels of progesterone, metabolites and hormones, which are key players in the dairy cow transition period, may confirm an important function of this peptide in metabolism regulation. Thus measurement of spexin concentration could provide useful supplementary information for dairy cow herd health monitoring.

Responses of beef calves to long-term heat stress exposure by evaluating growth performance, physiological, blood and behavioral parameters

The objective of this study was to explore the responses of beef calves to long-term heat stress (HS) exposure at various levels in comparison with the animals under thermoneutral conditions by evaluating growth performance, physiological, blood, and behavioural parameters. Data were collected from sixteen beef calves (BW: 136.9 ± 6.23 kg; age: 169.6 ± 4.60 d) kept at four stress levels of designated temperature humidity index (THI): threshold (22-24 °C, 60%; THI = 70 to 73), mild (26-28 °C, 60%; THI = 74 to 76), moderate (29-31 °C, 80%; THI = 81 to 83), and severe (32-34 °C, 80%; THI = 89 to 91) stress levels in climatic controlled chambers. Feed and water intake were recorded daily, and body weight was measured once a week. Blood was sampled every three days to analyse metabolite parameters. Dry matter intake (DMI) (p = 0.069, tendency) and blood glucose levels (p = 0.028) were decreased after sudden exposure to HS conditions (severe THI levels). Also, blood cortisol (p = 0.002), glutamic-oxaloacetic transaminase (GOT) (p = 0.009), blood urea nitrogen (BUN) (p = 0.004) and standing time (p = 0.009) were increased in moderate and severe THI levels compared with threshold after exposure to HS conditions. However, in the severe THI group, blood cortisol (p < 0.05), glucose (p < 0.05), GOT (p < 0.05) and BUN (p < 0.05) levels were returned to normal range after 6-13 days of continuous HS exposure. In conclusion, DMI, blood cortisol, GOT, glucose, BUN, and standing time were closely associated with long-term HS condition in beef calves. In addition, calves exposed to HS modulated their physiological responses that resulted in the regulation of the pertinent blood metabolites in the blood to maintain homeostasis during the long-term HS.

Effects of dietary forage to concentrate ratio on nutrient digestibility, ruminal fermentation and rumen bacterial composition in Angus cows

This study evaluated effects of dietary forage to concentrate ratio (F:C) on the body weight, digestibility, ruminal fermentation and rumen bacterial composition in Angus cows. Three diets with different F:C (LCD: 65:35, MCD:50:50, and HCD: 35:65) were fed to ninety Angus cows (3.2 ± 0.18 years old, 387.2 ± 22.6 kg). The average daily gain (ADG) and ammonia nitrogen concentration increased (P = 0.039 and P = 0.026, respectively), whereas the acetate to propionate ratio (P = 0.027) and the neutral detergent fiber (NDF) digestibility decreased with increasing concentrate level. The acetate concentration and ruminal pH (P = 0.033 and P = 0.029, respectively) decreased by feeding HCD diet. Serum amyloid A (SAA), C-reactive protein (CRP), haptoglobin (Hp) and lipopolysaccharide binding protein (LBP) increased under the HCD. The relative abundances of Bacteroidetes, Fibrobacterota, Prevotella and Prevotellaceae UCG-003 decreased, whereas the relative abundances of Ruminococcaceae NK4A214 group, Saccharofermentans and Spirochaetota increased with increasing dietary concentrate level. Our study provides a better understanding of rumen fermentation parameters and microbiota under a wide range of dietary F:C ratios, supporting the potential dietary manipulation of microbes, which could enhance feed digestibility associated with cow rearing.

Large-Scale International Validation of an Indirect ELISA Based on Recombinant Nucleocapsid Protein of Rift Valley Fever Virus for the Detection of IgG Antibody in Domestic Ruminants

Diagnostic performance of an indirect enzyme-linked immunosorbent assay (I-ELISA) based on a recombinant nucleocapsid protein (rNP) of the Rift Valley fever virus (RVFV) was validated for the detection of the IgG antibody in sheep (n = 3367), goat (n = 2632), and cattle (n = 3819) sera. Validation data sets were dichotomized according to the results of a virus neutralization test in sera obtained from RVF-endemic (Burkina Faso, Democratic Republic of Congo, Mozambique, Senegal, Uganda, and Yemen) and RVF-free countries (France, Poland, and the USA). Cut-off values were defined using the two-graph receiver operating characteristic analysis. Estimates of the diagnostic specificity of the RVFV rNP I-ELISA in animals from RVF-endemic countries ranged from 98.6% (cattle) to 99.5% (sheep) while in those originating from RVF-free countries, they ranged from 97.7% (sheep) to 98.1% (goats). Estimates of the diagnostic sensitivity in ruminants from RVF-endemic countries ranged from 90.7% (cattle) to 100% (goats). The results of this large-scale international validation study demonstrate the high diagnostic accuracy of the RVFV rNP I-ELISA. Standard incubation and inactivation procedures evaluated did not have an adverse effect on the detectable levels of the anti-RVFV IgG in ruminant sera and thus, together with recombinant antigen-based I-ELISA, provide a simple, safe, and robust diagnostic platform that can be automated and carried out outside expensive bio-containment facilities. These advantages are particularly important for less-resourced countries where there is a need to accelerate and improve RVF surveillance and research on epidemiology as well as to advance disease control measures.

Effects of achromatic and chromatic lights on pupillary response, endocrinology, activity, and milk production in dairy cows

Artificial light can be used as a management tool to increase milk yield in dairy production. However, little is known about how cows respond to the spectral composition of light. The aim of this study was to investigate how dairy cows respond to artificial achromatic and chromatic lights. A tie-stall barn equipped with light-emitting diode (LED) light fixtures was used to create the controlled experimental light environments. Two experiments were conducted, both using dairy cows of Swedish Red and light mixtures with red, blue or white light. In experiment I, the response to light of increasing intensity on pupil size was evaluated in five pregnant non-lactating cows. In experiment II 16h of achromatic and chromatic daylight in combination with dim, achromatic night light, was tested on pregnant lactating cows during five weeks to observe long term effects on milk production, activity and circadian rhythms. Particular focus was given to possible carry over effects of blue light during the day on activity at night since this has been demonstrated in humans. Increasing intensity of white and blue light affected pupil size (P<0.001), but there was no effect on pupil size with increased intensity of red light. Milk yield was maintained throughout experiment II, and plasma melatonin was higher during dim night light than in daylight for all treatments (P<0.001). In conclusion, our results show that LED fixtures emitting red light driving the ipRGCs indirectly via ML-cones, blue light stimulating both S-cones and ipRGCs directly and a mixture of wavelengths (white light) exert similar effects on milk yield and activity in tied-up dairy cows. This suggests that the spectral composition of LED lighting in a barn is secondary to duration and intensity.

Occurrence of Zearalenone and Its Metabolites in the Blood of High-Yielding Dairy Cows at Selected Collection Sites in Various Disease States

Zearalenone (ZEN) and its metabolites, alpha-zearalenol (α-ZEL) and beta-zearalenol (β-ZEL), are ubiquitous in plant materials used as feed components in dairy cattle diets. The aim of this study was to confirm the occurrence of ZEN and its selected metabolites in blood samples collected from different sites in the hepatic portal system (posthepatic-external jugular vein EJV; prehepatic-abdominal subcutaneous vein ASV and median caudal vein MCV) of dairy cows diagnosed with mastitis, ovarian cysts and pyometra. The presence of mycotoxins in the blood plasma was determined with the use of combined separation methods involving immunoaffinity columns, a liquid chromatography system and a mass spectrometry system. The parent compound was detected in all samples collected from diseased cows, whereas α-ZEL and β-ZEL were not identified in any samples, or their concentrations were below the limit of detection (LOD). Zearalenone levels were highest in cows with pyometra, where the percentage share of average ZEN concentrations reached 44%. Blood sampling sites were arranged in the following ascending order based on ZEN concentrations: EJV (10.53 pg/mL, 44.07% of the samples collected from this site), ASV (14.20 pg/mL, 49.59% of the samples) and MCV (26.67 pg/mL, 67.35% of the samples). The results of the study indicate that blood samples for toxicological analyses should be collected from the MCV (prehepatic vessel) of clinically healthy cows and/or cows with subclinical ZEN mycotoxicosis. This sampling site increases the probability of correct diagnosis of subclinical ZEN mycotoxicosis.

Serological test performance for bovine tuberculosis in cattle from herds with evidence of on-going infection in Northern Ireland

The ability to accurately identify infected hosts is the cornerstone of effective disease control and eradication programs. In the case of bovine tuberculosis, accurately identifying infected individual animals has been challenging as all available tests exhibit limited discriminatory ability. Here we assess the utility of two serological tests (IDEXX Mycobacterium bovis Ab test and Enfer multiplex antibody assay) and assess their performance relative to skin test (Single Intradermal Comparative Cervical Tuberculin; SICCT), gamma-interferon (IFNγ) and post-mortem results in a Northern Ireland setting. Furthermore, we describe a case-study where one test was used in conjunction with statutory testing. Serological tests using samples taken prior to SICCT disclosed low proportions of animals as test positive (mean 3% positive), despite the cohort having high proportions with positive SICCT test under standard interpretation (121/921; 13%) or IFNγ (365/922; 40%) results. Furthermore, for animals with a post-mortem record (n = 286), there was a high proportion with TB visible lesions (27%) or with laboratory confirmed infection (25%). As a result, apparent sensitivities within this cohort was very low (≤15%), however the tests succeeded in achieving very high specificities (96–100%). During the case-study, 7/670 (1.04%) samples from SICCT negative animals from a large chronically infected herd were serology positive, with a further 17 animals being borderline positive (17/670; 2.54%). Nine of the borderline animals were voluntarily removed, none of which were found to be infected post-mortem (no lesions/bacteriology negative). One serology test negative animal was subsequently found to have lesions at slaughter with M. bovis confirmed in the laboratory.

Short communication: Effects of dietary deoiled soy lecithin supplementation on circulating choline and choline metabolites, and the plasma phospholipid profile in Holstein cows fed palm fat

Dietary lecithin is a source of choline. Our objective was to evaluate the effects of dietary deoiled soy lecithin feeding on circulating choline, choline metabolites, and the plasma phospholipid profile in lactating dairy cows fed fractionated palm fatty acids. In a split-plot Latin square design, 16 Holstein cows (160 ± 7 d in milk; 3.6 ± 1.2 parity) were randomly allocated to a main plot receiving a corn silage and alfalfa haylage-based diet with palm fat containing either moderate or high palmitic acid content at 1.75% of ration dry matter (moderate and high palmitic acid containing 72 or 99% palmitic acid in fat supplement, respectively; n = 8/palm fat diet). Within each palm fat group, deoiled soy lecithin was top-dressed at 0, 0.12, 0.24, or 0.36% of ration dry matter in a replicated 4 × 4 Latin square design with 14-d experimental periods. A 14-d covariate period was used to acclimate cows to palm fat feeding without lecithin supplementation. Blood sampling occurred during the final 3 d of each experimental period. Plasma choline and choline metabolites were quantified using liquid chromatography and mass spectrometry. Plasma phospholipids were profiled using time-of-flight mass spectrometry. Whereas no effects of treatments were detected for plasma choline or methionine, lecithin feeding increased the plasma concentrations of choline metabolites trimethylamine N-oxide and dimethylglycine (24 and 11%, respectively). Plasma phosphatidylcholine (PC) and sphingomyelin (SM) concentrations increased with deoiled lecithin feeding (e.g., PC 16:0/22:6 and SM d18:1/18:3). Lecithin supplementation also increased plasma lysophosphatidylcholine (LPC) concentrations (e.g., LPC 18:0) while reducing plasma phosphatidylethanolamine (PE) concentrations (e.g., PE 16:0/20:5). Although increases in microbial-derived trimethylamine N-oxide suggest gastrointestinal lecithin degradation, elevations in plasma dimethylglycine, PC, LPC, and SM suggest that choline availability was improved by lecithin feeding in cows, thus supporting enhanced endogenous phospholipid synthesis.

Pattern of postruminal administration of l-tryptophan affects blood serotonin in cattle

Serotonin (5-HT) has many important functions in both central and peripheral nervous systems. Although it has been demonstrated that manipulation of serotonin metabolism is possible in many species, there is limited information about l-tryptophan (TRP), a serotonin precursor, in cattle, and these provide conflicting results. Furthermore, there is no study evaluating how different patterns of intra-abomasal infusion of TRP impact circulating 5-HT. The objective of this study was to evaluate if intra-abomasal infusion patterns of TRP can affect circulating 5-HT and other metabolites from TRP metabolism in the plasma and serum and circulating glucose and insulin in cattle. Eight ruminally cannulated Holstein steers were used in a replicated 4 × 4 Latin square design. Each received intra-abomasal water infusion (control) or intra-abomasal TRP infusion (50 mg/kg BW) in 3 different patterns: a pulse infusion once a day (pulse once), pulse infusion twice a day (pulse twice), or continuous infusion (continuous). For continuous treatment, the TRP dose was diluted in tap water and infused by a peristaltic pump (300 mL/h). To equalize conditions, the other treatments had a water infusion (300 mL/h). The steers were fed every 2 h, and blood was collected from a jugular vein catheter every 4 h for 24 h after the initial infusion. Urine produced during the 24 h period was collected. Serum and plasma TRP, 5-HT and kynurenine, plasma glucose, and serum insulin concentrations were analyzed. Urine was analyzed for concentrations of 5-hydroxyindoleacetic acid. Both serum TRP and kynurenine were increased (P < 0.05) by all TRP infusion treatments, but concentrations in pulse dose treatments were greater than those in continuous infusion. Serum 5-HT increased (P < 0.05) with both pulse TRP infusion treatments; however, the continuous TRP infusion did not increase the serum 5-HT. Plasma 5-HT, glucose, and insulin had a tendency to increase with TRP pulse infusions. The urinary 5-hydroxyindoleacetic acid excretion was highest for pulse dose treatments. An acute supply of TRP in 1 or 2 daily doses increases serum 5-HT and increases circulating glucose and insulin in cattle. The TRP and kynurenine concentrations are similar in plasma and serum. However, the serum 5-HT concentration is more responsive to TRP administration than plasma.

Determinants of vitamin D status in Kenyan calves

Vitamin D plays a critical role in calcium homeostasis and in the maintenance and development of skeletal health. Vitamin D status has increasingly been linked to non-skeletal health outcomes such as all-cause mortality, infectious diseases and reproductive outcomes in both humans and veterinary species. We have previously demonstrated a relationship between vitamin D status, assessed by the measurement of serum concentrations of the major vitamin D metabolite 25 hydroxyvitamin D (25(OH)D), and a wide range of non-skeletal health outcomes in companion and wild animals. The aims of this study were to define the host and environmental factors associated with vitamin D status in a cohort of 527 calves from Western Kenya which were part of the Infectious Disease of East African Livestock (IDEAL) cohort. A secondary aim was to explore the relationship between serum 25(OH)D concentrations measured in 7-day old calves and subsequent health outcomes over the following 12 months. A genome wide association study demonstrated that both dietary and endogenously produced vitamin D metabolites were under polygenic control in African calves. In addition, we found that neonatal vitamin D status was not predictive of the subsequent development of an infectious disease event or mortality over the 12 month follow up period.

Effects of Dietary Rumen-Protected Betaine on Lactation Performance and Serum Metabolites of Mid-lactation Holstein Dairy Cows

This experiment was conducted to investigate the effects of dietary rumen-protected betaine (RPB) supplementation, as partial replacement for methionine, on the lactation performance of mid-lactation dairy cows. A total of 36 Holstein dairy cows were randomly assigned to three groups [control, 20 g/day RPB, or 15 g/day rumen-protected methionine (RPM)]. The experiment was conducted over 9 weeks, with the first week for adaptation. Blood metabolites were analyzed with metabolomics in the control and RPB groups. The results revealed that the milk yield and milk protein content were higher in cows fed RPB and RPM compared to those in the control group. Concentrations of nine metabolites differed between cows in the RPB and control groups. These metabolites were mainly concentrated in six pathways, such as arginine synthesis and proline degradation and cyanoamino acid synthesis. This study revealed that RPB can spare methionine and improve lactation performance of dairy cows fed with diets moderately deficient in methionine.

Determination of Steroids in Bovine Serum: Validation of a Reliable LC-MS/MS Method and In Vivo Studies with Boldenone Undecylenate and Testosterone Propionate

Serum analysis has received much attention in regulatory analysis of food-producing animals, especially for anabolic steroids. The possibility of confirming the parent drugs with minimum metabolization enables the detection of intact steroid esters, whose identification represents unequivocal proof of drug administration. This work involved the development and validation of a quantitative LC-MS/MS method to determine 30 steroids and steroid esters in bovine serum. Sensitivity was improved using microwave-assisted chemical derivatization with methoxyamine hydrochloride. The validation was successfully conducted in accordance with the Decision 657/2002/EC guidelines. An in vivo experiment was performed on 12 crossbred steers in which two commercial formulations containing boldenone undecylenate and testosterone propionate were administrated via intramuscular injections. The samples were collected over a period of 120 days, in which both intact esters were identified within 11 days postadministration. 17β-Boldenone was observed after 92 days for 2 steers and 56 days for the other animals. The applicability of a cut-off level to the ratio between 17β-testosterone and epitestosterone was evaluated in an attempt to differentiate testosterone abuse from endogenous production. It could be observed that a calculated ratio above this level is strong evidence of drug administration, although a high false-negative rate was obtained.

Metabolomic analysis of organic acids, amino acids, and fatty acids in plasma of Hanwoo beef on a high-protein diet

INTRODUCTION

Ketoacidosis of metabolic disease showed in beef cattle although body weight was increased by high-grain diets (HGDs). However, few studies have examined for health status related with metabolic disease of ketoacidosis following high-protein diet (HPD).

OBJECTIVES

Metabolomic analysis was performed for the monitoring of health status associated with metabolic disease of ketoacidosis in the plasma of Hanwoo heifers following a HPD.

METHODS

Hanwoo heifers of 24 months with 459 ± 42 kg weight were used under a 2 × 2 crossover design. The plasma was collected from control (n = 5) and HPD group (n = 5) on day 21 following diet adaptation for 20 days. Metabolic profiling analysis of organic acids (OAs), amino acids (AAs) and fatty acids (FAs) by gas chromatography-tandem mass spectrometry combined with star pattern analysis was performed in plasma. Levels of OAs, AAs and FAs were evaluated by Mann-Whitney test, PCA and PLS-DA.

RESULTS

In HPD group, ketoacidosis as metabolic disease was monitored by elevated acetoacetic acid and 3-hydroxybutyric acid. In addition, the elevation of ketogenic AAs, reduction of medium chain FAs and OAs with energy metabolism in TCA cycle were monitored in HPD group. Star graphic pattern was characteristic and readily distinguished between control and HPD groups. In PLS-DA, two groups were separated with VIP score of top-ranked 10 FAs as important metabolites for discrimination.

CONCLUSION

Elevation of ketone body including ketogenic AAs and reduced energy metabolism of FAs and OAs may useful for evaluation of health states associated with ketoacidosis from metabolic event by HPD in beef cattle.

Quantitative Analysis of Ethyl Carbamate in Distillers Grains Co-products and Bovine Plasma by Gas Chromatography-Mass Spectrometry

Ethyl carbamate (EC) is a fermentation byproduct in foods and beverages and classified as a Group 2A probable human carcinogen. Each year, greater than 40 million metric tons of fermentation co-products from the U.S. ethanol industry are fed to food animals. A gas chromatography-mass spectrometry assay was developed to quantify EC extracted from various distillers grains co-products with a limit of detection at 0.7 ng/g (on an as-fed basis). EC was detected in all the distillers grains co-products surveyed in this study. Corn condensed distillers solubles contained the highest concentration of EC, ranging from 1618 to 2956 ng/g. Concentrations of EC in other types of distillers grains co-products varied from 17 to 917 ng/g. Cattle fed distillers grains co-products that constituted 19-38% of the total feed (as-fed) were found to contain 2-3 ng/mL of EC in blood plasma. No EC was detected in blood plasma from grass-fed control cattle.

Grouping crossbred Holstein x Gyr heifers according to different feed efficiency indexes and its effects on energy and nitrogen partitioning, blood metabolic variables and gas exchanges

The objectives of this study were: i) to classify animals into groups of high and low feed efficiency (FE) using three FE indexes (Residual feed intake (RFI), Residual weight gain (RG) and Feed conversion efficiency (FCE)), and ii) to evaluate whether crossbreed Holstein x Gyr heifers divergent for FE indexes exhibit differences in nutrient intake and digestibility, energy partitioning, heat production, methane emissions, nitrogen partitioning and blood parameters. Thirty-five heifers were housed in a tie-stall, received ad libitum TMR (75:25, corn silage: concentrate) and were ranked and classified into high (HE) or low efficiency (LE) for RFI, RG and FCE. The number of animals for each HE group were 13 (< 0.5 standard deviation (SD) for RFI, 11 for RG and 11 for FCE (> 0.5 SD) and for the LE were 10 (> 0.5 SD) for RFI, 11 for RG and 12 for FCE (< 0.5 SD). Gas exchanges (O₂ consumption, CO₂ and CH₄ production) in open-circuit respiratory chambers and whole tract digestibility trial was performed. A completely randomized experimental design was used and the data were analyzed by ANOVA and correlation study. High efficiency animals for RFI produced less CO_2, consumed less O₂ and had lower heat production (HP). Methane production was positively correlated with RFI. High efficiency RG had higher O₂ consumption and CO₂ production in relation to LE-RG. High efficiency FCE had greater NFC digestibility, higher positive energy balance (EB) and excreted (11.4 g/d) less nitrogen in urine. High efficiency RG and FCE groups emitted less CH₄ per kg of weight gain than LE animals. Animals HE for RFI and FCE had lower β-hydroxybutyrate and higher glucose concentrations, respectively. The differences in intake, digestibility, energy and nitrogen partition, CH₄ emission, blood metabolic variables and heat production between the HE and LE groups varied according to the efficiency indexes adopted. The HP (kcal/d/BW^0.75) was lower for HE animals for RFI and FCE indexes.

Cytokines in the grass, a lesson learnt: Measuring cytokines in plasma using multiple reaction monitoring mass spectrometry

RATIONALE

Cytokines are cell regulatory molecules of high importance as indicators for homeostasis and pathology in many species. The current method to measure cytokines in body fluids is reagent dependent, requiring highly specific paired antibodies.

METHODS

A liquid chromatography/multiple reaction monitoring mass spectrometry (LC/MRM-MS)-based approach was developed to simultaneously establish the limits of detection (LODs) and quantification (LOQs) for recombinant cytokines IL-1β, IL-6, IFNγ and TNFα as pure standards and in bovine sera. All experimental LC/MRM-MS data are available at CSIRO Data Access Portal repository under identifier doi.org/10.25919/5de8a0232a862.

RESULTS

The present method enabled LODs and LOQs as low as 1.05 and 1.12 fmol/μL in the experiment comprised of pure standards. Comparable results were obtained in the experiment where digested cytokines were mixed with pre-digested sera proteins. The intrinsic matrix effects were evident when intact cytokines were co-digested within undiluted and undigested sera decreasing the ability to detect and quantify cytokines by 10,000-fold compared with pure standards and pre-digested sera.

CONCLUSIONS

The developed LC/MRM-MS method provided insights into the difficulties in detecting the target peptides when embedded in complex matrices. Nonetheless, the method may potentially be readily applied in biomarker-focused research interrogating fluids of lesser complexity such as synovial fluid, cerebrospinal fluid and tissue culture media.

Night-restricted feeding of dairy cows modifies daily rhythms of feed intake, milk synthesis and plasma metabolites compared with day-restricted feeding

The timing of feed intake can alter circadian rhythms of peripheral tissues. Milk synthesis displays a daily rhythm across several species, but the effect of feeding time on these rhythms is poorly characterised. The objective of this experiment was to determine if the time of feed intake modifies the daily patterns of milk synthesis, plasma metabolites and body temperature in dairy cows. Sixteen lactating Holstein dairy cows were randomly assigned to one of the two treatment sequences in a cross-over design with 17 d periods. Treatments included day-restricted feeding (DRF; feed available from 07.00 to 23.00 hours) and night-restricted feeding (NRF; feed available from 19.00 to 11.00 hours). Cows were milked every 6 h on the last 7 d of each period, and blood samples were collected to represent every 4 h over the day. Peak milk yield was shifted from morning in DRF to evening in NRF, while milk fat, protein and lactose concentration peaked in the evening in DRF and the morning in NRF. Plasma glucose, insulin, NEFA and urea nitrogen concentration fit daily rhythms in all treatments. Night feeding increased the amplitude of glucose, insulin and NEFA rhythms and shifted the daily rhythms by 8 to 12 h (P < 0·05). Night feeding also phase-delayed the rhythm of core body temperature and DRF increased its amplitude. Altering the time of feed availability shifts the daily rhythms of milk synthesis and plasma hormone and metabolite concentrations and body temperature, suggesting that these rhythms may be entrained by food intake.

Colostrum supplementation with n-3 fatty acids and α-tocopherol alters plasma polyunsaturated fatty acid profile and decreases an indicator of oxidative stress in newborn calves

Our objective was to characterize the effects of supplementing newborn calves with n-3 fatty acids (FA) and α-tocopherol on blood lipid profiles and oxidant status in early life. Sixteen calves received 0 or 60 mL of 1:1 fish and flaxseed oil with 200 mg of α-tocopherol in 2.8 L of colostrum within 6 h after birth. Colostrum was >22% on the Brix scale. Blood was sampled on d 1, 2, 4, 7, 14, and 21 after birth for assessment of plasma polyunsaturated FA, α-tocopherol, total serum protein, and oxidant status index, an indirect indicator of oxidative stress that examines the balance between the concentration of reactive oxygen and nitrogen species and antioxidant capacity in serum. Health was observed daily. Weight and hip height were recorded at birth, 3 wk, and 8 wk. Data were analyzed with a Mixed procedure of SAS 9.4 (SAS Institute Inc., Cary, NC). Treatment did not alter concentration of total protein in blood serum, prevalence of diarrhea or other signs of disease, or rate of growth. Feeding n-3 FA and α-tocopherol increased plasma concentrations of the n-3 FA, including α-linolenic, eicosapentaenoic, and docosahexaenoic acids, with a concomitant decrease in oxidant status index during the first week of life. Concentrations of α-tocopherol decreased with supplementation, but all calves maintained adequate concentrations. Oxidant status index of treated calves returned to the level of control calves by d 14. We conclude that a colostrum supplement of n-3 FA and α-tocopherol is safe to administer to newborn calves, reduces oxidant status in the first week of life, and may improve health and performance.

The seroprevalence of brucellosis and molecular characterization of Brucella species circulating in the beef cattle herds in Albania

Background

Brucellosis is a ubiquitous zoonotic disease globally. It is endemic among bovines, sheep, and goats in Albania. The national control and eradication programs for brucellosis has been applied on sheep and goat farms as well as large dairy cattle farms, i.e., those with more than ten milking cows. The current study aims at estimating the herd and average individual animal prevalence of brucellosis in the national beef cattle herds, the missing information that was essential to propose the most appropriate control measures for this sub-population. Rose Bengal Test (RBT), Fluorescence Polarization Assay (FPA), and Enzyme-Linked Immunosorbent Assay (ELISA) were used as serological tests and classical bacteriology for isolation. Results were also used to investigate the difference in sensitivity between the assays used.

Methodology

In total, 655 animals from 38 beef cattle herds from six southern districts of Albania were sampled. Sera were tested using RBT, FPA, and ELISA. Fifteen positive cows and a bull from eight high-prevalence positive herds were slaughtered, and particular tissue samples were collected for bacteriology.

Results

The overall herd seroprevalence in the tested beef cattle population was 55%, while the overall average within-herd prevalence (including only positive herds) was 38.3%, 42.7%, and 45.6% determined by the RBT, ELISA, and FPA, respectively. FPA was used for the first time in the diagnosis of bovine brucellosis in Albania, and its sensitivity was higher than RBT and ELISA. Three B. abortus strains were identified, two from the supra-mammary lymph node of two cows and one from the epididymis of a seropositive bull.

Conclusion

Brucellosis was highly prevalent in beef cattle in the southern part of Albania, and B. abortus was isolated from this subpopulation. To the best of our knowledge, this is the first statistically based survey of bovine brucellosis in beef herds in Albania. Using the FPA in parallel with other serological tests improved overall diagnostic sensitivity. Test and slaughter policy is not a rational approach for the control of brucellosis in beef cattle in Albania, and vaccination is only applicable, including strict control of the movement of animals.

Inline Reticulorumen pH as an Indicator of Cows Reproduction and Health Status

Our study hypothesis is that the interline registered pH of the cow reticulum can be used as an indicator of health and reproductive status. The main objective of this study was to examine the relationship of pH, using the indicators of the automatic milking system (AMS), with some parameters of cow blood components. The following four main groups were used to classify cow health status: 15-30 d postpartum, 1-34 d after insemination, 35 d after insemination (not pregnant), and 35 d (pregnant). Using the reticulum pH assay, the animals were categorized as pH < 6.22 (5.3% of cows), pH 6.22-6.42 (42.1% of cows), pH 2.6-6.62 (21.1% of cows), and pH > 6.62 (10.5% of cows). Using milking robots, milk yield, fat protein, lactose level, somatic cell count, and electron conductivity were registered. Other parameters assessed included the temperature and pH of the contents of reticulorumens. Assessment of the aforementioned parameters was done using specific smaX-tec boluses. Blood gas parameters were assessed using a blood gas analyzer (EPOC (Siemens Healthcare GmbH, Erlangen, Germany). The study findings indicated that pregnant cows have a higher pH during insemination than that of non-pregnant ones. It was also noted that cows with a low fat/protein ratio, lactose level, and high SCC had low reticulorumen pH. They also had the lowest blood pH. It was also noted that, with the increase of reticulorumen pH, there was an increased level of blood potassium, a high hematocrit, and low sodium and carbon dioxide saturation.

Effects of utilizing cotton byproducts in a finishing diet on beef cattle performance, carcass traits, fecal characteristics, and plasma metabolites

Increased cotton production in the Southwestern United States has increased the availability of cotton byproducts for use in cattle diets. The objective of this experiment was to evaluate the inclusion of cotton byproducts in feedlot finishing diets on the performance, carcass traits, fecal characteristics, and plasma metabolites of steers. Crossbred beef steers (n = 64; BW = 318 ± 12.3 kg) were assigned to 1 of 2 experimental treatments in a randomized complete block design (8 pens per treatment; 4 steers per pen). Treatments included a control (CON) diet, which included prairie hay, Sweet Bran, rolled corn, and a corn steep and molasses-based liquid fat supplement, and a cotton byproduct (CTN) diet, which included cotton gin trash, whole cottonseed, rolled corn, and water. Both diets contained urea and dry supplement. Over the entire feeding period, DMI (P = 0.04) was greater for CTN steers than CON steers with no difference in the gain to feed ratio (P = 0.86) between treatments. The CTN steers tended to have heavier final BW (P = 0.09) and greater overall average daily gain (P = 0.08). The CTN steers had heavier hot carcass weight (P = 0.02) and greater fat thickness (P = 0.03) than CON steers, but marbling score and rib eye area were not different between treatments (P ≥ 0.64). Steers fed the CON diet tended to have a lower yield grade (P = 0.07), less kidney, pelvic and heart fat (P = 0.09), and decreased dressing percentage (P = 0.10) than CTN steers. Liver scores did not differ (P ≥ 0.17) between treatments. Fecal consistency scores were decreased for CTN steers on day 56 (P = 0.03) and fecal pH tended to be greater for the CTN steers on day 28 (P = 0.09) compared with CON steers, but neither differed during other periods (P ≥ 0.18). A treatment × day interaction (P = 0.04) was detected for plasma urea nitrogen (PUN) concentrations, where PUN concentrations differed between treatments only on days 28 and 56. On both days 28 and 56, CTN steers had lower PUN concentrations (P = 0.03, P = 0.002, respectively). No treatment × day interaction was detected for plasma glucose or lactate concentrations. A day effect was observed for both metabolites (P < 0.01). Results from this experiment suggest that cotton byproducts can be effectively used as a source of fiber, fat, and protein in feedlot rations without adverse effects on performance or carcass characteristics.

Vitamin A, calcium, phosphorus and magnesium status of heifers grazing in Northern Cyprus

Vitamin A, calcium (Ca), phosphorus (P) and magnesium (Mg) are essential components for the health and reproductive yield of dairy cows. In this study, it is aimed to profile the calcium, phosphorus and magnesium elements together with vitamin A, which are important components in cattle bred and reared in Northern Cyprus. To analyse these parameters, 260 clinically healthy animals, at least 30 from each region, were blood sampled from eight different regions (Nicosia, Gecitkale, Vadili, Famagusta, Iskele, Ziyamet, Morphou and Kyrenia) during both summer and winter seasons. Vitamin A, calcium, magnesium and phosphorus concentrations were measured from blood samples. Vitamin A levels increased significantly only in Nicosia and Ziyamet regions during the winter season, while there was no seasonal difference from the other regions. Calcium and phosphorus levels were higher in summer when compared with winter. Magnesium levels were significantly higher in winter than in summer. In the comparison between regions in summer and winter, the change in P and Mg values was significant, whereas Ca only showed inter-regional differences during winter. In conclusion, all the parameters found were within the expected ranges but affected by seasonal changes. Therefore, we think that calcium and phosphorus supplementation in winter and vitamin A and magnesium supplementation in summer will provide positive results on cattle.

Cortisol and Blood Urea Nitrogen Profiles in Fertile and Repeat-breeder Holstein-friesian Crossbred Cows

BACKGROUND AND OBJECTIVE

Repeat breeding, in which conception fails after repeated inseminations is a major problem in the dairy industry that leads to economic losses. To examine the role of stress under this condition, this study was conducted to evaluate cortisol and blood urea nitrogen (BUN) levels in fertile and repeat-breeder Holstein-friesian crossbred cows in smallholder farms.

MATERIALS AND METHODS

Thirty cows were divided into two groups: Fertile and repeat-breeder cows, with 15 cows per group. Blood samples were collected from the caudal vein at night, 8 h after feeding, once in the oestrus phase during two oestrus cycles and cortisol levels were analyzed by using an enzyme-linked immunosorbent assay with a commercial kit. The BUN was analyzed by the urease and glutamate dehydrogenase method.

RESULTS

Significant differences in cortisol and BUN levels were observed between fertile and repeat-breeder cows. Cortisol levels were higher in the repeat-breeder group (6.860±1.427 ng mL-1) compared to those in the fertile group (3.145±1.103 ng mL-1). Furthermore, BUN levels were also higher in repeat-breeder cows (31.45±4.70 mg dL-1) than in fertile cows (27.30±2.69 mg dL-1).

CONCLUSION

Cortisol and BUN levels above the normal range may contribute to repeat breeding in Holstein-friesian crossbred cows.

Characterization of metabolic and inflammatory profiles of transition dairy cows fed an energy-restricted diet

Periparturient diseases of dairy cows are caused by disproportionate energy metabolism, mineral imbalance, and perturbed immune function. The aim of the present study was to characterize metabolism, innate immune endometrial gene expression, and uterine microbial populations of transition animals receiving normal or restricted energy diets. Pregnant multiparous Holstein cows (n = 14) were randomly assigned to one of the two dietary treatments from 20 d prepartum until 35 d postpartum (DPP). One group was fed a diet providing 100% energy requirements (NE), whereas the other received an energy-restricted diet providing 80% energy requirements (RE). Feed intake, milk yield, body weight, body condition score, temperature, respiratory, and pulse rate were recorded. After calving, blood was collected weekly to analyze nonesterified fatty acids (NEFAs), β-hydroxybutyrate (BHB), and total cholesterol (TC). Endometrial cytobrushes were collected for gene expression analysis of inflammatory markers, microbial populations determination, and cytological evaluation. The restricted energy diet did not alter feed intake or milk yield but changed energy balance and metabolites levels (P < 0.05). In fact, RE animals had high NEFA and BHB levels, and low TC concentrations (P < 0.05). Moreover, RE animals had upregulated gene expression of serum amyloid A3 (SAA3) at 35 DPP (P < 0.05) and CXC chemokine receptor 2 (CXCR2) at 14 DPP (P < 0.01). Interleukin (IL) 1 and IL8 genes were downregulated 14 DPP but upregulated 35 DPP in RE animals, whereas IL6 and lipopolysaccharide-binding protein (LBP) genes were upregulated at 14 DPP (P ≤ 0.05). The most abundant phyla in RE animals (n = 3) were Bacteroidetes and Fusobacteria, whereas Proteobacteria was the least abundant at both 14 and 35 DPP. In conclusion, it can be speculated that energy balance is one of the main drivers for uterine inflammation by affecting metabolism, immune function, and uterine microbiota. However, these findings should be validated in a larger sample size.

Detection of bovine serum albumin using hybrid TiO2 + graphene oxide based Bio - resistive random access memory device

Bio - molecules detection and their quantification with a high precision is essential in modern era of medical diagnostics. In this context, the memristor device which can change its resistance state is a promising technique to sense the bio - molecules. In this work, detection of the Bovine Serum Albumin (BSA) protein using resistive switching memristors based on TiO2 and TiO2 + graphene oxide (GO) is explored. The sensitivity of BSA detection is found to be 4 mg/mL. Both the devices show an excellent bipolar resistive switching with an on/off ratio of 73 and 100 respectively, which essentially demonstrates that the device with GO, distinguishes the resistance states with a high precision. The enhanced performance in the GO inserted device (~ 650 cycles) is attributed to the prevention of multi-dimensional and random growth of conductive paths.

Effects of a blend of Saccharomyces cerevisiae-based direct-fed microbial and fermentation products in the diet of newly weaned beef steers: growth performance, whole-blood immune gene expression, serum biochemistry, and plasma metabolome1

We examined the effects of dietary supplementation of a Saccharomyces cerevisiae-based direct-fed microbial (DFM) on the growth performance, whole-blood immune gene expression, serum biochemistry, and plasma metabolome of newly weaned beef steers during a 42 d receiving period. Forty newly weaned Angus crossbred steers (7 d post-weaning; 210 ± 12 kg of BW; 180 ± 17 d of age) from a single source were stratified by BW and randomly assigned to 1 of 2 treatments: basal diet with no additive (CON; n = 20) or a basal diet top-dressed with 19 g of the DFM (PROB; n = 20). Daily DMI and weekly body weights were measured to calculate average daily gain (ADG) and feed efficiency (FE). Expression of 84 immune-related genes was analyzed on blood samples collected on days 21 and 42. Serum biochemical parameters and plasma metabolome were analyzed on days 0, 21, and 42. On day 40, fecal grab samples were collected for pH measurement. Compared with CON, dietary supplementation of PROB increased final body weight (P = 0.01) and ADG (1.42 vs. 1.23 kg; P = 0.04) over the 42 d feeding trial. There was a tendency for improved FE with PROB supplementation (P = 0.10). No treatment effect (P = 0.24) on DMI was observed. Supplementation with PROB increased (P ≤ 0.05) the concentrations of serum calcium, total protein, and albumin. Compared with CON, dietary supplementation with PROB increased (P ≤ 0.05) the expression of some immune-related genes involved in detecting pathogen-associated molecular patterns (such as TLR1, TLR2, and TLR6), T-cell differentiation (such as STAT6, ICAM1, RORC, TBX21, and CXCR3) and others such as TNF and CASP1, on day 21 and/or day 42. Conversely, IL-8 was upregulated (P = 0.01) in beef steers fed CON diet on day 21. Plasma untargeted plasma metabolome analysis revealed an increase (P ≤ 0.05) in the concentration of metabolites, 5-methylcytosine and indoleacrylic acid involved in protecting the animals against inflammation in steers fed PROB diet. There was a tendency for lower fecal pH in steers fed PROB diet (P = 0.08), a possible indication of increased hindgut fermentation. This study demonstrated that supplementation of PROB diet improved the performance, nutritional status, and health of newly weaned beef steers during a 42 d receiving period.

Reciprocal combinations of alfalfa hay and corn silage in the starter diets of Holstein dairy calves: effects on growth performance, nutrient digestibility, rumen fermentation and selected blood metabolites

Adding corn silage (CS) instead of alfalfa hay (AH) to the finely ground starter diet would improve calf performance if feed intake or feed efficiency is increased. We investigated the effects of replacing AH with CS in the starter diet on nutrient intake, digestibility, growth performance, rumen fermentation and selected blood metabolites in Holstein calves. Newborn male calves (n = 30; 3 days of age; 40.2 ± 1.28 kg BW) were assigned randomly to three groups receiving starter diets containing chopped AH (10% dry matter (DM) basis; AH diet), CS (10% DM, CS diet) or their combination (each at 5% level; AHCS diet). The starter diets had the same nutrient composition but differed in DM content (91.2%, 87.5% and 83.8% for AH, AHCS and CS, respectively). The calves were weaned on day 50, and the study continued until day 70. Nutrient intake, BW (at weaning and at the end of the study) and body measurements were not affected by the diet. During the post-weaning period, average daily gain tended to be greater on CS than on AH diet. Feed efficiency was greater in CS than in AH or AHCS calves during the post-weaning period. Digestibility of neutral detergent fiber was greater in AHCS and CS compared with AH during the post-weaning period. Concentration and profile of volatile fatty acids and ruminal fluid pH were not affected by the diet. Replacing AH with CS in the starter diet had no effect on feed intake, growth performance and general health of the calves. These results indicate that AH and CS can be used interchangeably in dairy calf starter diets until 70 days of age, allowing dairy producers more choices in selecting the feed ingredients.

Effects of increasing diet fermentability on intake, digestion, rumen fermentation, blood metabolites and milk production of heat-stressed dairy cows

Heat stress is a major problem for dairy cows in hot climates, thus coping strategies are essential. This study evaluated the effects of increasing diet fermentability on intake, total tract digestibility, ruminal pH and volatile fatty acids (VFA) profile, blood metabolite profile and milk production and composition of lactating dairy cows managed under conditions of ambient heat stress. Nine multiparous cows (650 ± 56 kg BW; mean ± SD) averaging 102 ± 13 days in milk and producing 54 ± 6 kg/day were randomly assigned to a triplicate 3 × 3 Latin square. During each 21-day period, cows were offered one of three total mixed rations that varied in diet fermentability. The three levels of diet fermentability were achieved by increasing the proportion of pellets containing ground wheat and barley in the dietary DM from 11.7% (low), to 23.3% (moderate), and 35.0% (high) by replacing ground corn grain. Each period had 14 day of adaptation and 7 day of sampling. The ambient temperature-humidity index ( ≥ 72) indicated that the cows were in heat stress almost the entire duration of the study. Also, rectal temperature of cows was elevated at 39.2°C, another indication of heat stress. Increasing diet fermentability linearly decreased dry matter intake (22.8, 22.5, 21.8 kg/day for low, moderate and high, respectively; P ≤ 0.05) but increased non-fibre carbohydrate digestibility (P ≤ 0.05) and tended to increase digestibility of DM (P = 0.10) and crude protein (P = 0.06). As a result, the intake of digestible DM was not affected by the treatments. The production of 3.5% fat corrected milk (32.6, 33.7, and 31.5 kg/day) was quadratically (P ≤ 0.05) affected by diet fermentability with lower production for the high diet compared with the other two, which were similar. Rumen pH (ruminocentesis) and proportions of butyrate and isovalerate linearly decreased whereas propionate proportion linearly increased with increasing diet fermentability (P ≤ 0.05). The rumen concentration of NH3-N (11.0, 9.0, and 8.7 mg/dL) and blood concentration of urea linearly decreased with increasing diet fermentability (P ≤ 0.05). The activity of alkaline phosphatase increased (65.1, 83.2, and 84.9 U/l) and concentration of malondialdehyde decreased (2.39, 1.90 and 1.87 µmol/l) linearly with increasing diet fermentability (P ≤ 0.05), which indicated possible attenuation of the effects of oxidative stress with increasing diet fermentability. Overall, a modest increase of diet fermentability improved nitrogen metabolism, milk protein production and oxidative stress of heat-stressed dairy cows, but a further increase in diet fermentability decreased milk yield.

Investigation of Heavy Metal Levels in Blood Samples of Three Cattle Breeds in Turkey

The aim of this study is to determine seasonal changes in the blood levels of some heavy metals in three Turkey-specific cattle breed: Native Land (NL), Grizzle Race (GR), and South Anatolian Red (SR). Blood samples were collected in summer and winter seasons from a total of 180 cattle aged 12-24 months. The levels of the essential (Zn, Cu, Fe, Co etc.) and non-essential (Cd, Hg, As, Cr, Pb, etc.) heavy metals were analyzed. All heavy metal levels, except that of Co, were significantly higher (p < 0.05) in SR in both seasons compared to the other species. In all breeds, Fe and Co levels were statistically higher (p < 0.05) in the summer season while Mn level was higher (p < 0.05) in the winter season. The levels of all metals analyzed are within the internationally acceptable limits for cattle breeds.

Increasing serotonin bioavailability in preweaned dairy calves impacts hematology, growth, and behavior

Peripheral serotonin has been shown to regulate important physiological functions such as energy homeostasis and immunity, particularly in rodent and humans, but its role is poorly understood in livestock species. Herein, we tested the safety and effectiveness of increasing serotonin bioavailability in preweaned dairy calves by oral supplementation of a serotonin precursor (5-hydroxytryptophan, 5-HTP) or a serotonin reuptake inhibitor (fluoxetine, FLX). Bull Holstein calves (21 ± 2 d old; N = 24) were fed milk replacer (8 L/d) supplemented with either saline as control (CON, 8 mL/d, n = 8), FLX (40 mg/d, approx. 0.8 mg/kg; n = 8), or 5-HTP (90 mg/d, approx. 1.8 mg/kg; n = 8) for 10 consecutive days in a complete randomized block design. Heart rate (HR), respiration rate, rectal temperature, and health scores were recorded daily. Hip height and body weight were measured at d 1, 5, and 10 relative to initiation of supplementation. Blood samples were collected once before the supplementation period (d 1), during the 10-d supplementation period (daily), and during a 14-d withdrawal period (d 2, 3, 4, 7, and 14 relative to initiation of withdrawal). Cerebrospinal fluid and muscle tissue were collected from a subset of calves (n = 12) that were euthanized after the 10-d supplementation or 14-d withdrawal period. Whole blood serotonin concentrations increased in 5-HTP calves and decreased in FLX calves compared with CON (P < 0.001), indicating that serotonin bioavailability was increased in both groups. Whole blood serotonin concentrations of 5-HTP and FLX calves returned to CON levels after 7 d of withdrawal. All calves grew and were considered healthy throughout the study. In fact, calves fed 5-HTP had higher average daily gain compared with CON (0.87 vs 0.66 ± 0.12 kg/d, P = 0.05). Calves fed FLX had lower HR (P = 0.02) and greater red blood cells and hemoglobin counts on d 10 of supplementation compared with CON (P < 0.01). After the 14-d withdrawal period, FLX was not detected in circulation of FLX calves, but was still present in the muscle tissue. Our results demonstrate that manipulation of the serotonin pathway by supplementing FLX or 5-HTP is a feasible and safe approach in preweaned dairy calves; however, it takes more than 14 d for FLX to be completely withdrawn from the body.

Circulating adiponectin concentrations during the transition from pregnancy to lactation in high-yielding dairy cows: testing the effects of farm, parity, and dietary energy level in large animal numbers

Dairy cows experience a negative energy balance due to increasing energy demands and insufficient voluntary feed intake in the transition from late pregnancy to early lactation. For supplying sufficient energy toward the conceptus and the mammary gland, insulin sensitivity in peripheral tissues is reduced leading to adipose tissue mobilization. Adiponectin, an insulin-sensitizing adipokine, is presumably related to energy metabolism and could play an important role in these metabolic adaptations. We hypothesize (1) that primiparous cows would differ from pluriparous cows in their circulating adiponectin concentrations during the transition from late pregnancy to early lactation and (2) that feeding different energy levels would affect the adiponectin concentrations during early lactation in dairy cows. For the first hypothesis, we examined 201 primiparous and 456 pluriparous Holstein dairy cows on three experimental farms. Ante partum, primiparous cows had lower adiponectin and greater NEFA concentrations than pluriparous cows, but vice versa post partum. Hence, adiponectin might be involved in the energy partitioning in primiparous cows (conceptus and lactation vs other still growing body tissues) with changing priorities from pregnancy to lactation. For the second hypothesis, 110 primiparous and 558 pluriparous Holstein and Simmental dairy cows in six experimental farms received either roughage with 6.1 or 6.5 MJ NEl/kg dry matter (adjusted with different amounts of wheat straw) ad libitum, combined with either 150 or 250 g concentrates/kg energy corrected milk. Greater amounts of concentrate lead to greater milk yield, but did not affect the blood variables. The higher energy level in the roughage led to greater glucose and IGF-1 but lower adiponectin in pluriparous cows. Further studies are needed to elucidate the mechanisms behind the roughage effect and its metabolic consequences.

Association between prepartum metabolic status and resumption of postpartum ovulation in dairy cows

Cows transitioning from late gestation to early lactation experience an increase in energy demands, which lead to a negative energy balance (NEB) because the greater energy requirement is not fully synchronized with the intake of dry matter. In this context, there is an increase in plasma NEFA and ghrelin concentrations and a decrease in plasma insulin and glucose-dependent insulinotropic polypeptide (GIP) concentrations. This situation could have a negative impact on the return to cyclicity because some of these variables have been associated with reduced GnRH and LH pulsatility (high NEFA and low insulin concentrations). However, there are no studies showing the relationship between ghrelin or GIP and reproductive performance. It is known that these hormones are related with lipolysis and NEB, with NEB being one of the main determinants of GnRH pulse generator activity. Thus, the objective of the present study was to evaluate the association between plasma NEFA concentration and metabolic hormones (insulin, ghrelin, and GIP) before parturition and their associations with the resumption of postpartum ovulations in dairy cows. A completely randomized block design was used in a commercial dairy herd with sampling day (visit to farm) as the blocking criteria. Holstein cows (n = 92) were screened for plasma NEFA concentration -5 d (±2 d) relative to the expected parturition day, and top and bottom quartiles were considered as high (H-NEFA) and low (L-NEFA) NEFA groups. Data were analyzed with correlation, linear regression, and proportional hazard regression models. Plasma NEFA concentration (H-NEFA mean = 294 μM, SD = 141.2; and L-NEFA mean = 122 μM, SD = 25.3) was correlated (P < 0.01) with plasma insulin (r = -0.374) and ghrelin (r = -0.346) concentrations but not with plasma GIP concentration (P = 0.64). The greater the concentration of insulin, the lesser the prepartum NEFA concentration (for each 1 μU/mL of plasma insulin increase, there is a decrease of 1.223 ± 0.62 μM of NEFA). Plasma ghrelin and GIP concentrations were not associated with plasma NEFA concentration. Finally, H-NEFA prepartum cows were less likely to resume ovulation than L-NEFA cows (hazard ratio [HR] = 0.563, 95% confidence interval [CI] = 0.314-1.011), whereas high ghrelin cows were more likely to resume ovulation than low ghrelin cows (HR = 1.873, 95% CI = 0.846-4.145). Conversely, resumption of ovulation was not associated with prepartum insulin and GIP concentrations. Prepartum NEFA and possibly ghrelin are associated with the return to postpartum cyclicity; however, insulin and GIP are not related to the resumption of ovulation in dairy cows.

Technical note: Glucose concentration in dairy cows measured using 6 handheld meters designed for human use

The objective was to evaluate the precision and accuracy of 6 handheld glucose meters, designed for human use [Accu-Chek Aviva Plus (AC), Roche Diabetes Care, Mannheim, Germany; Aga Matrix (AM), AgaMatrix Inc., Salem, NH; Contour Next (CT), Bayer HealthCare LLC, Leverkusen, Germany; FreeStyle Precision Neo (FS), Abbott Diabetes Care Ltd., Alameda, CA; Nova Max Plus (NM), Nova Biomedical Corporation, Waltham, MA; and Precision Xtra (PX), Abbott Diabetes Care Ltd., Witney, UK] to measure blood glucose concentration in dairy cows. Blood samples from Jersey and Jersey × Holstein crossbreed cows (n = 97 for all; except CT, n = 71) were collected and analyzed in triplicate using the 6 handheld glucose meters evaluated. Plasma glucose was also measured with the laboratory reference method (hexokinase glucose-6-phosphate dehydrogenase). Based on the intra-assay coefficient of variation (CV), precision varied across handheld glucose meters: AC (2.2%), CT (4.0%), PX (4.7%), FS (5.6%), AM (6.2%), and NM (6.7%). Lin's concordance correlation coefficients between handheld glucose meters and the reference method were 0.75 for FS, 0.74 for PX, 0.62 for AC, 0.55 for CT, 0.53 for NM, and 0.48 for AM. Based on Passing-Bablok regression, the AM and PX meters showed bias in the measurements of blood glucose. Bland-Altman plots indicated a negative bias (FS = -0.25 mmol/L; CT = -0.60 mmol/L) or a positive bias (AM = 0.29 mmol/L; PX = 0.33 mmol/L; NM = 0.52 mmol/L; AC = 0.65 mmol/L) between handheld glucose meters and the reference method. All handheld glucose meters evaluated had wide limits of agreement (LoA) ranging from -0.18 to 1.47 mmol/L (AC, narrowest LoA) to -1.25 to 1.82 mmol/L (AM, widest LoA). Bias was the major contributor to the total observed error (TE_obs), accounting for 81.5% of the TE_obs in AC, 72.0% in CT, 64.9% in AM, 61.1% in NM, 57.8% in PX, and 56.2% in FS. Overall, although some handheld meters (AC, CT, and PX) showed satisfactory precision, none were accurate measuring glucose. Future studies should evaluate whether incorporating algorithms designed for cattle can improve accuracy and precision of handheld glucose meters.

Serum biochemistry in cows of different breeds presented with reproductive conditions

Minimising health problems and increasing yield have always been the objectives in livestock agriculture. Hence, increases in incidences of reproductive conditions in cattle farming pose a great threat to productivity and impose undesirable economic implications. This study aimed to examine the concentrations of different biochemical compounds in cows with reproductive conditions. Seventy-seven blood samples were collected from cows at different rural areas around Mafikeng, following cases of downer cow syndrome, dystocia, retained placenta, vaginal prolapse and abortion. Means of serum metabolites across the different reproductive conditions were statistically compared using Pearson's chi-square test to determine variations of serum metabolites in cows of different breeds. In mixed breed cows, higher than normal calcium concentrations were observed in downer cow syndrome (25.25 ± 8.47) and dystocia (85.50 ± 8.46) cases. It was also observed that cholesterol concentrations were significantly low in abortion (2.52 ± 0.79), retained placenta (3.18 ± 0.61) and vaginal prolapse (2.37 ± 0.97) cases in Afrikaner cows. The study showed that Brahman (43.1%) and Afrikaner (43.1%) breeds were mostly affected by downer cow syndrome. Additionally, the occurrences of downer cow syndrome (53.9%) and abortions (60%) were mostly observed in cows of 1-3 years, in second and first parities, respectively. This study proves that concentrations of calcium, urea or blood urea nitrogen (BUN), magnesium and cholesterol are significantly altered in incidences of reproductive conditions in cows of different breeds. It is also shown that serum biochemistry is affected by reproductive conditions in cows of different ages and parity. This data serves as a tool that could be used to enhance research in animal production and reproduction.

Serum Apelin-36 alteration in late pregnancy and early lactation of dairy cows and its association with negative energy balance markers

The beneficial roles of Apelin on both energy metabolism and insulin sensitivity have been described in previous researches, but it has been little studied in dairy cows. The aim of the present study was to determine the serum Apelin-36 concentration in late pregnancy and early lactation in dairy cows and its association with negative energy balance markers. Thirty Holstein dairy cows (multiparous; n = 15 and primiparous; n = 15) with body condition score 3-3.75 at parturition were selected and blood samples were obtained for metabolic profile one month before and one month after parturition. Apelin-36, glucose, insulin, β-hydroxybutyric acid (BHBA), non-esterified fatty acid (NEFA), cholesterol, triglyceride (TG) and high density lipoproteins (HDL) were measured using commercial kits. BCS and milk production were recorded during the study. There was no effect of parity on Apelin-36, cholesterol, TG, HDL, BHB and NEFA concentrations before lactation; while insulin and glucose levels were higher in primiparous cows than multiparous cows at this period. None of the factors showed any significant difference between multiparous and primiparous cows after lactation. Serum NEFA concentration were increased after parturition, while Apelin-36, insulin and glucose concentrations were decreased after parturition in primiparous and multiparous cows. Significant correlations were observed between serum Apelin and insulin (P = .041, r = 0.672), NEFA (P = .027, r = -0.808) and glucose (P = .037, r = 0.757). In conclusion, our results showed that serum Apelin-36 concentration decreased after parturition in dairy cow. Alteration of Apelin-36 secretion after parturition may represent an endocrine adaptation in dairy cow during the lactating period.

Bovine dopamine type-2 receptor SNP has no effect on growth, semen characteristics and prolactin concentrations in beef bulls treated with a dopamine agonist

A dopamine type-2 receptor (DRD2) SNP, previously found to be correlated with serum prolactin (PRL) concentrations in cattle, was evaluated for impact on growth traits, serum prolactin concentration, and semen quality. Over a four-year period, yearling beef bulls were allowed diets containing or lacking ergot alkaloids (EA). Every 21 or 28 d semen was collected for semen motility and morphology assessment and blood samples were collected to measure serum PRL concentrations. In addition, body condition score and scrotal circumference were evaluated. Serum PRL concentrations were assessed using a radioimmunoassay. In the first year, all bulls were sacrificed at the end of a 126-day study. Testicles and epididymis were collected at the end of the study or 60 days after removal from treatment. Immunohistochemistry was performed on testis, epididymis, and sperm cells, incubated with or without a primary antibody for DRD2 and counterstained with DAPI. Isolation of DNA was performed on sperm pellets using DNAzol (Thermo Fisher Scientific, Waltham, MA, USA) methods. Polymerase chain reaction was performed to amplify the region of the DRD2 gene containing the SNP of interest. The products were subjected to restriction fragment length polymorphism analysis. Further, all samples were subjected to genotyping using a custom Taqman genotyping assay (Applied Biosystems, Foster city, CA, USA). The presence of DRD2 was detected in the testis, epididymis, and sperm cells. The DRD2 genotype was not associated with semen quality, serum PRL, or growth traits. Consumption of EA resulted in lesser PRL serum concentrations but had no effect on values for other variable examined.

Effect of passive transfer of immunity on growth performance of preweaned dairy calves

The primary objective of this observational study was to examine the association between passive transfer of immunity and growth performance in preweaning calves. A secondary objective was to evaluate the utility of a heart girth tape (HGT) to estimate body weight (BW) in preweaning calves. A total of 142 Holstein calves were enrolled in this study. Blood samples were collected 24 to 48 hours after birth and serum immunoglobulin G (IgG) concentration for each calf was measured by radial immunodiffusion assay. Calf BW was determined at birth, at 21 days, and at weaning using an electronic scale (ES) and HGT. A significant positive association was detected between serum IgG and both BW at 21 days and average daily gain (ADG) from 0 to 21 days of life. Additionally, ADG from 0 to 42 days of life showed a trend toward an improved rate of gain as IgG concentration increased. The Pearson correlation coefficient between BW obtained from ES and HGT was 0.81 at birth, 0.86 at 21 days, and 0.83 at weaning. The mean differences between BW obtained from ES and HGT were -3.1 kg at birth, -3.2 kg at 21 days, and -7.7 kg at weaning. In conclusion, serum IgG concentration in neonatal calves is an important contributing factor for the variation in growth performance of preweaning calves. The HGT can be used to estimate the BW of preweaning calves but has a tendency to overestimate weight, especially at weaning compared to birth and 21 days of age.

Correlation between estrogen plasma level and miRNAs in muscle of Piedmontese cattle

A loss-of-function mutation of the myostatin gene has a very high prevalence in the Piedmontese cattle breed. The effect of such mutation is a double-muscle phenotype because of hypertrophy. However, differences in muscle mass development can still be detected in individuals of this breed. Such differences must be generated by other factors controlling skeletal muscle development. MicroRNAs are short noncoding RNA molecules that modulate gene expression at a post-transcriptional level. MicroRNAs have been demonstrated to be involved in skeletal muscle development, and some of them are controlled by steroid hormone signaling. Data on estrogen signaling are lacking, whereas more studies have been carried out on the effect of androgens. We aimed at identifying putative estrogen responsive miRNAs that might be involved in skeletal muscle development. At a slaughterhouse, we collected muscle samples from longissimus dorsi and blood samples. Blood 17β-estradiol concentration was assessed, and RNA was extracted from muscle samples. The animals we sampled were divided into groups according to estrogen blood concentration, and through qPCR expression, levels of 7 muscle-related miRNAs were evaluated. We found that miR-26b (P < 0.01), miR-27a-5p (P < 0.05), miR-27b (P < 0.05), and miR-199a-3p (P < 0.01) were differentially expressed among experimental groups. Expression levels of miR-26b were reduced approximately 50% in samples with a low blood estrogen concentrations, and the other miRNAs showed a tendency to increase their expression levels when blood estrogen levels were higher. The variations of the circulating concentrations of estrogen in Piedmontese cattle might influence muscle mass development through miRNAs and thus contribute to individual variability in a breed with a high prevalence of a myostatin point mutation.

Acid-base assessment of post-parturient German Holstein dairy cows from jugular venous blood and urine: A comparison of the strong ion approach and traditional blood gas analysis

Evaluating acid-base status is important for monitoring dairy herd health. In a field study, we aimed to compare the acid-base status measured by net acid-base excretion (NABE) in urine with results of venous blood analysis in clinically healthy, but possibly metabolically burdened cows in their transition period. For this, we sampled blood from the jugular vein and urine from 145 German Holstein cows within 1 to 76 days post-partum. In blood, the metabolic parameters non-esterified fatty acids (NEFA) and β-hydroxybutyrate (BHB), as well as numerous parameters of the acid-base status were measured. The traditional approach, based on bicarbonate concentration, base excess (BE) and anion gap (AG), was compared to the strong ion approach variables, e.g. acid total (Atot), measured strong ion difference (SIDm), strong ion gap (SIG), and unmeasured anions (XA), respectively. Results of both approaches were set against the outcome of urine analysis, i.e. the NABE, base-acid ratio and pH of urine, in a cluster analysis, which provided 7 moderately stable clusters. Evaluating and interpreting these 7 clusters offered novel insights into the pathophysiology of the acid-base equilibrium in fresh post-partum dairy cows. Especially in case of subclinical acid-base disorders, the parameters of the strong ion difference theory, particularly SIDm, Atot and SIG or XA, provided more in-depth information about acid-base status than the traditional parameters BE, bicarbonate or AG in blood. The acid-base status of fresh cows with protein aberrations in blood could be differentiated in a much better way using the strong ion approach than by traditional blood gas analysis or by the measurement of urinary excretion. Therefore, the strong ion approach seems to be a suitable supplement for monitoring acid-base balance in dairy cattle.

Metabolomics Reveals that Crossbred Dairy Buffaloes Are More Thermotolerant than Holstein Cows under Chronic Heat Stress

Heat stress (HS) threatens the worldwide dairy industry by decreasing animal production performance and health. Holstein cows and dairy buffaloes are the most important dairy animals, but their differences in the metabolic mechanism of thermotolerance remain elusive. In this study, we used serum metabolomics to evaluate the differences in thermotolerance between Holstein cows and crossbred dairy buffaloes under chronic heat stress (HS) and thermal-neutral conditions. In response to HS, the body temperatures and respiratory rates were increased more for Holstein cows than for dairy buffaloes (38.78 vs 38.24 °C, p < 0.001; 43.6 vs 32.5 breaths/min, p < 0.001). HS greatly affected serum metabolites associated with amino acids, fatty acids, and bile acids. The enriched metabolic pathways of these serum metabolites are closely related to HS. We demonstrated that buffaloes adapt to HS by adopting a metabolism of branched-chain amino acids and ketogenic amino acids and gluconeogenesis, but Holstein cows decrease the effect of HS with citrulline and proline metabolism. Both physiological parameters and serum metabolic profiles indicate that dairy buffaloes are more thermotolerant than Holstein cows, providing the feasibility to vigorously develop the buffalo dairy industry in tropical and subtropical regions.

Seroprevalence and risk factors of brucellosis among slaughtered indigenous cattle, abattoir personnel and pregnant women in Ngaoundéré, Cameroon

BACKGROUND

Brucellosis is a neglected debilitating zoonosis with a high prevalence in many developing countries. Bovine brucellosis is widespread in Cameroon but the epidemiological situation of human brucellosis is not known. A cross sectional study was carried to determine the seroprevalence and factors associated with bovine and human Brucellosis among abattoir personnel and pregnant women in Ngaoundéré, Cameroon.

METHODS

Serum sample from 590 abattoir cattle and 816 plausible occupational risk and vulnerable humans to brucellosis (107 abattoir personnel and 709 pregnant women) were collected and screened for anti-brucella antibodies using Rose Bengal Plate Test (RBPT) and ELISA tests. Structured questionnaires were used to collect data on socio-demographics and risk-factors. The differences in proportions between seropositive and seronegative reactors were tested using odds-ratio and χ2tests.

RESULTS

Bovine brucellosis seroprevalence was at 3.40% (n = 590; 3.4% for RBPT, 5.93% for i-ELISA). Human Brucella seroprevalence was at 5.6% among abattoir personnel (n = 107; 5.6% for RBPT, 12.15% for Brucella IgG ELISA) and 0.28% in pregnant women (n = 709; both tests). Breed (P < 0.00001) was associated with increased risk of brucellosis in cattle and the seroprevalence was highest among the Djafoun (OR = 16.67, 95%CI: 4.49-28.85) and Akou (OR = 16.96, 95% CI: 0.10-23.91) cattle compared to the other breeds. There was a moderate positive correlation (R2 = 0.5025) of Brucella IgG concentrations (> 200 U/ml) and clinical data for Brucella IgG ELISA seropositive humans. Several potential factors were associated (P > 0.05) with increased risk of human brucellosis seroprevalence among the abattoir personnel. The abattoir personnel were essentially males; the seropositive respondents were male and did not use protective equipment at work. Handling of foetus and uterine contents (OR = 13.00, 95%CI: 1.51-111.88) was associated with increased risk of human brucellosis.

CONCLUSIONS

Antibrucella antibodies are prevalent in cattle (3.40%), among abattoir personnel (5.60%) and in pregnant women (0.28%) in Ngaoundéré, Cameroon. The study reports the first evidence of human brucellosis in Cameroon and therefore, an indication of a real public health problem. Public awareness campaigns and health education especially among livestock professional and in agropastoral communities should be highlighted to disseminate knowledge, associated risk factors and control measures of brucellosis.

Bioavailability of Quercetin from Onion Extracts after Intraruminal Application in Cows

The aim of the present study was to investigate the bioavailability of quercetin from onion bulb (OB) and onion skin (OS) extracts in ruminants. Three non-lactating cows equipped with a permanent rumen fistula intraruminally received equimolar amounts of quercetin as either aglycone, rutin, or OB or OS extract, respectively, at a dose of 50 mg of quercetin equivalents/kg of body weight. Blood samples were drawn before and frequently within the 24 h period after application of the respective substance. Quercetin and quercetin metabolites with an intact flavonol structure (kaempferol, isorhamnetin, and tamarixetin) were analyzed in plasma samples by high-performance liquid chromatography with fluorescence detection. All quercetin sources administered resulted in a fast increase of the plasma concentrations of quercetin and total flavonols (sum of quercetin and its metabolites), followed by a rapid decline, whereby significant higher concentrations occurred with OB extract and rutin compared to quercetin aglycone and OS extract, respectively. The results clearly demonstrate a higher systemic availability of quercetin from OB extract and rutin. Taken together, OB extract with a high content of quercetin glucosides is an interesting source for the application of quercetin to ruminants.

Effect of dietary nitrogen level and source on mRNA expression of urea transporters in the rumen epithelium of fattening bulls

This paper aims to study the effect of the dietary treatments on mRNA expression of urea transporter B (UT-B) and some aquaporins (AQP) in rumen epithelium of Italian Simmental young bulls. Eighty animals allocated to 16 pens were fed from about 500 to 650 kg body weight with four experimental diets, which resulted from the combination of two crude protein levels (125 and 110 g/kg dry matter, diets M and L, respectively) and two nitrogen sources (soybean meal (SBM) or SBM partly replaced by an isonitrogenous mixture of corn and urea; diets -U and +U, respectively). At slaughtering samples of blood and rumen epithelium were collected from six bulls for each diet. Blood samples were analysed for haematological parameters and quantitative PCR was carried out on the mRNA extracted from the rumen epithelium samples. The bulls fed diets M had lower plasma concentrations of aspartate aminotransferase than those receiving diets L (78.9 vs. 88.3 U/l, p = 0.04). Plasma urea was higher (p = 0.03) for diets M and lower for diets +U (2.0 vs. 2.5 and 1.73 vs. 2.00 mmol/l, respectively, in M and L diets, p = 0.04). The effect of dietary treatments on rumen UT expression were limited to AQP3, which was down regulated (p = 0.01) in diets +U. Finally, a high positive correlation (R2 = 0.871) between the expressions of AQP7 and AQP10 was found. In conclusion, the AQP3 appears very responsive to dietary treatments and therefore it is a candidate to be further studied in rumen metabolism experiments. The close relationship between mRNA expression of AQP7 and AQP10 indicates a similar function of these two proteins.

Nulliparous and primiparous cows produce less fertile female offspring with lesser concentration of anti-Müllerian hormone (AMH) as compared with multiparous cows

Nutritional partitioning to fetal development differ among nulliparous, primiparous and multiparous cows, leading to birth of smaller calves to nulliparous and primiparous than multiparous dams. The prenatal nutritional state could influence ovarian reserve and fertility in the adult offspring. The effect of maternal parity on ovarian reserve and reproduction of female offspring, however, has not been investigated in cattle. Accordingly, a retrospective research was conducted to study reproductive variables in nulliparous- (n = 310), primiparous- (n = 236) and multiparous-born (n = 323) female offspring during the first four lactation periods in dairy cows. Additionally, anti-Müllerian hormone (AMH), as a reliable marker of ovarian reserve, was measured in a subset of nulliparous- (n = 51), primiparous- (n = 51) and multiparous-born (n = 49) female offspring. Birth weight in multiparous-born calves was greater than that in nulliparous- and primiparous-born calves (P <  0.01). Days to first service was shorter in multiparous-born female offspring as compared with nulliparous- and primiparous-born female offspring (P <  0.05). First service conception rate, proportion of repeated breeders, service per conception and calving to conception interval were greater in multiparous-born than nulliparous-born cows (P <  0.05). Cumulative culling rate was greater in primiparous-born cows than nulliparous- and multiparous-born cows (P <  0.05). The AMH concentration was greater in multiparous-born than nulliparous- and primiparous-born cows (P <  0.05). In conclusion, the present study revealed that in comparison with multiparous cows, nulliparous and primiparous cows, particularly nulliparous cows, produce female offspring with lesser reproductive performance and smaller size of ovarian reserves.

Effects of monensin on growth performance of beef heifers consuming warm-season perennial grass and supplemented with sugarcane molasses

The objective of this study was to evaluate the effects of monensin on performance of beef heifers fed warm-season forages. Brangus heifers (n = 24) were stratified by BW and BCS, and randomly assigned into 1 of 12 bahiagrass pastures (1.2 ha and 2 heifers/pasture). Heifers were offered 14 kg of sugarcane molasses and 3.5 kg of cottonseed meal weekly from day 0 to 84. Treatments were randomly assigned to pastures (6 pastures/treatment) and consisted of heifers supplemented with or without 200 mg/day of monensin. On d 85, heifers were allocated to individual drylot pens, provided free choice access to bermudagrass hay, and received their respective treatment for 10 d of adaptation and 11 d of data collection. Monensin did not impact (P ≥ 0.13) heifer BW, BCS, overall ADG, bahiagrass IVDOM, CP, herbage mass, and allowance. Supplement disappearance after 10 and 34 h of supplementation was greater for control vs. monensin heifers (P = 0.04) and tended to be greater for control vs. monensin heifers 24 h post-supplementation (P = 0.07). Plasma concentrations of glucose, IGF-1, and BUN (P ≥ 0.24) did not differ between treatments. From d 85 to 106, forage and total DM intake, in vivo DM digestibility, and heifer growth performance did not differ between treatments (P ≥ 0.12). Therefore, adding monensin to sugarcane molasses-based supplements decreased supplement consumption rate, but did not impact growth and blood parameters of heifers grazing warm-season grasses with limited nutritive value.

Metabolomics Profiling of Serum and Urine in Three Beef Cattle Breeds Revealed Different Levels of Tolerance to Heat Stress

This study was to determine differences in the global metabolic profiles of serum and urine of Xuanhan yellow cattle, Simmental crossbred cattle (Simmental × Xuanhan yellow cattle), and cattle-yaks (Jersey × Maiwa yak) under heat stress (temperature-humidity index remained above 80 for 1 week). A total of 55 different metabolites associated with the three breeds were identified in the serum and urine samples by gas chromatography-mass spectrometry. The metabolic adaptations to heat stress are heterogeneous. Cattle-yaks mobilize a greater amount of body protein to release glucogenic amino acids to supply energy, whereas the tricarboxylic acid cycle is inhibited. Simmental crossbred cattle mobilize a greater amount of body fat to use free fatty acids as an energy source. In comparison with Simmental crossbred cattle and cattle-yaks, Xuanhan yellow cattle have higher glycolytic activity and possess a stronger antioxidant defense system and are, in conclusion, more adapted to hot and humid environments.

Lactation-related changes in tissue expression of PEDF in dairy cows

Pigment epithelium-derived factor (PEDF) is evolving as metabolic regulatory protein. Albeit mostly considered in only pathological conditions related to excess energy intake resulting in obesity and insulin resistance, PEDF is likely to be involved in other physiological processes such as the homeorhetic adaptation of metabolism to lactation. We aimed to characterize the expression of PEDF and its association to the concomitant mobilization of body reserves during lactation in nonobese subjects. This mobilization is particularly distinct in dairy cows, and we therefore assessed the mRNA expression of PEDF and its putative receptors in different tissues in 2 trials with dairy cows fed with or without conjugated linoleic acids (CLAs). Conjugated linoleic acids depress milk fat synthesis and may thus reduce the drain of energy via milk. In pluriparous cows, the serum PEDF concentrations and the mRNA abundance in subcutaneous adipose tissue (scAT), as well as the hepatic and scAT mRNA abundance of the putative receptors, adipose triglyceride lipase, and laminin receptor 1, changed over time of sampling (day -21 until day 252 relative to calving). Conjugated linoleic acid treatment was associated with reduced PEDF concentrations in serum and lower PEDF mRNA abundance in scAT on day 21 postpartum. Comparing different tissues from primiparous cows, PEDF mRNA was highest in the liver, followed by scAT, visceral adipose tissue (AT), and mammary gland, and lowest in the muscle. Significant changes in PEDF expression with time of sampling were limited to AT in primiparous and pluriparous cows. Our data support a regulatory role for PEDF. The similarities between the time course of the serum concentrations of PEDF and its mRNA abundance in scAT may point to a regulatory role for AT rather than the liver for PEDF in dairy cows.