Investigating the effects of concentrate supplement level and type on milk fat production and animal performance of spring-calving grazing dairy cows

The objective of this experiment was to investigate the effect of concentrate supplement level and type on the milk fat production of grazing dairy cows in early to mid-lactation during a high-risk period for reduced milk fat synthesis. Eighty Holstein Friesian dairy cows averaging (mean ± SD) 55 ± 14 DIM were blocked based on their pre-experimental milk production and parity and randomly assigned to 1 of 5 dietary treatments: a pasture-only (P) control supplemented with 0.27 kg of DM/cow per day of a mineral and vitamin pack (P0); P supplemented with 2 kg of DM/cow per day of an industry-standard concentrate (P2); P supplemented with 4 kg of DM/cow per day of an industry-standard concentrate (P4); P supplemented with 4 kg of DM/cow per day of a concentrate containing 10% sodium hydroxide-treated straw (P4S); and P supplemented with 4 kg of DM/cow per day of a concentrate containing 5% calcium salts of fatty acids (P4F). The experiment consisted of an initial 2-wk covariate period, 1 wk of diet acclimatization, and a 12-wk period of data collection. Concentrate supplement level and type had no effect on milk fat concentration. Increasing the concentrate supplementation level linearly increased milk yield, ECM yield, fat yield, protein yield, lactose yield, and milk solids yield. Cows fed P4F had greater milk yield and lactose yield but lower milk protein concentration compared with cows fed P4 and P4S. Compared with the P4S diet, cows fed the P4F diet had greater milk fat yield and tended to produce greater milk solids yield. Cows fed P4F had lower proportions of de novo and mixed fatty acids (FA), as well as greater proportions of preformed FA compared with cows fed P4 and P4S. Cows fed P2 and P4 increased DM and OM intake compared with cows fed P0; however, cows fed P2 and P4 were similar. The total FA intake of cows fed P4 was greatest (400 g/d), cows fed P2 was intermediate (370 g/d), and cows fed P0 was lowest (330 g/d). Changing the concentrate type had no effect on the intakes of total DM, pasture DM, and OM. These results suggest that, although concentrate level and type can affect milk fat yield, they do not affect the milk fat concentration of grazing dairy cows within the conditions investigated in this experiment. Further research is required to determine the nutritional and non-nutritional factors responsible for reducing milk fat concentration in pasture-based systems during the high-risk period.

A large multisite lipidomic investigation of parity and aging in dairy cows

Efforts to optimize the longevity of dairy cows are hindered by the increased risk of adverse health events, culling, or dying on farm with increased parity. Lipidomics provides a platform to help identify important biomarkers and biological pathways associated with increased parity and associated aging. A large multisite (15 pasture-based, 15 TMR farms) cross-sectional study collected plasma samples from nonlactating, late pregnant, dry cows (n = 696, ∼27 d prepartum) and peak milk cows (n = 796, ∼58 DIM) in a disproportionate stratified random sampling frame (parity: 0, 1, 2, >2 for dry cows; 1, 2, 3, >3 for peak milk cows). A total of 185 lipid species, comprising the lipids classes of phospholipids, sphingomyelins (SM) and triacylglycerols, were quantified in a targeted, liquid chromatography-MS approach. Dry and peak milk cohorts were analyzed separately throughout. Variation in lipid profiles were mostly attributed to farm of origin (36%-41% of variation), with feeding system explaining 13% to 21% and parity explaining 6% to 9%, according to ANOVA simultaneous component analysis modeling. Multiple linear regression and orthogonal partial least squares (O-PLS) investigated the association of the lipid profile with age (d), whereas discriminant analysis compared first parity with >3 parity cows in O-PLS discriminant analysis, random forest, and support vector machine models. Rankings of the most important lipid species for each model type were compared. Phospholipids with 40 carbon atoms and 6 double bond equivalents (40:6) were consistently decreased with increasing parity and age across both dry and peak milk cohorts. These lipids most likely contained stearate (18:0) and docosahexaenoic acid (DHA, C22:6n-3), an n-3 fatty acid. Additionally, phospholipids with 40:5 and 38:6, lysophosphatidylcholine (17:0), SM(35:1), and SM(35:2) were commonly identified lipids that decreased in concentration with parity and age. Docosahexaenoic acid has been associated with improved cattle health, reproduction, and milk production and quality. This study raises the hypothesis that reduced DHA levels in older cows may be an important factor increasing susceptibility to adverse health events, reduced reproductive performance, and herd removal. Studies that supplement DHA or its precursors can test this hypothesis and may be important in optimizing longevity of cows.

Conjugated linoleic acid in cheese: A review of the factors affecting its presence

Several health benefits of conjugated linoleic acid (CLA) have been documented. The present work is aimed to review data on the various factors affecting the CLA content in cheese of studies accomplished in the last decade and also indicating the factors that increase the CLA levels. The CLA content in cheese depends on CLA levels present in milk, since the lipids with the CLA are transferred from milk into the cheese. Feed types rich in α-linolenic and linoleic acids such as pasture grass, plant oils, cereals rich in oil, or fish oils can affect the CLA level in milk. In contrast to findings of previous reviews made in previous decade, which stated that the CLA levels in cheese were stable during ripening time, the present review reveals that certain lactic acid bacteria, that is, probiotic Lactiplantibacillus plantarum, Lactobacillus acidophilus, or Lacticaseibacillus casei, as well as Bifidobacterium lactis can increase the CLA levels in cheese by converting linoleic acid during ripening time. These bacteria starters increased the CLA levels by 1.19, 1.6, and 6.6 times as much as the control in Ovine model, Miniature, and Cheddar cheese, respectively. Lipid oxidation due to factors like fluorescent light or aerobic conditions can decrease the CLA levels during storage.

Variations in the milk lipidomic profile of lactating dairy cows fed the diets containing alfalfa hay versus alfalfa silage

Alfalfa is primarily stored as silage or hay in livestock production. Previous research has shown that the storage method of grass significantly influences milk composition. This study aimed to investigate milk production performance and lipid composition in dairy cows fed diets consisting of alfalfa hay or alfalfa silage as roughage. Forty-two mid-lactation Holstein dairy cows were selected and randomly divided into three groups, each receiving a total mixed ration consisting of alfalfa hay (AH), 50% alfalfa silage + 50% alfalfa hay (AHAS), or alfalfa silage (AS). The results showed that milk fat content (P = 0.049) and milk fat yield (P < 0.001) were significantly higher in the AH and AHAS groups compared to the AH group. With increased supplementation of alfalfa silage in the diet, ω-3 polyunsaturated fatty acid content increased significantly (P < 0.001), while ω-6 polyunsaturated fatty acid content (P = 0.007) and the ratio of ω-6 to ω-3 polyunsaturated fatty acids decreased (P < 0.001). The contents of sphingomyelins, phosphatidylserines, phosphatidylethanolamines, and phosphatidylglycerols in the AHAS and AS samples were higher than in the AH samples, although the differences were not statistically significant. Additionally, the content of phosphatidylcholines was significantly higher in the AS group compared to the AH group (P = 0.032). In conclusion, feeding dairy cows a diet consisting of alfalfa silage can increase the major phospholipid content and polyunsaturated fatty acid composition in raw milk, which is more conducive to human health. These findings provide valuable insights into the benefits of alfalfa silage for dairy cows.

Potential strategies to enhance conjugated linoleic acid content of milk and dairy products: A review

Conjugated linoleic acid (CLA) is a general term for all the geometric and positional isomers of linoleic acid. The cis-9, trans-11 CLA and trans-10 cis-12 CLA are considered to be the most abundant and essential isomers associated with health benefits. Though milk and dairy products are considered to be the major sources of CLA, the CLA content found in regular milk and dairy products is relatively low for effective health benefits in human beings. Thus, for effective health benefits, increasing the concentration of CLA in milk and dairy products is beneficial. Dietary supplementation with PUFA-rich lipid sources such as oilseeds and/or vegetable oils, fish meal, fish oil and microalgae and grass-based feeding can enhance the content of CLA in milk and dairy products. Application of CLA-producing bacterial strains during the fermentation process and ripening/storage are considered as potential strategies for enhancing the CLA content of fermented dairy products. Alternatively, the CLA content of milk and dairy products can be improved using genetic factor. In this paper, the latest scientific studies regarding CLA enrichment in milk and dairy products are reviewed, giving an overview of the effectiveness of the different CLA enrichment strategies and their combinations.

Accounting for minimum data required to train a machine learning model to accurately monitor Australian dairy pastures using remote sensing

Precision in grazing management is highly dependent on accurate pasture monitoring. Typically, this is often overlooked because existing approaches are labour-intensive, need calibration, and are commonly perceived as inaccurate. Machine-learning processes harnessing big data, including remote sensing, can offer a new era of decision-support tools (DST) for pasture monitoring. Its application on-farm remains poor because of a lack of evidence about its accuracy. This study aimed at evaluating and quantifying the minimum data required to train a machine-learning satellite-based DST focusing on accurate pasture biomass prediction using this approach. Management data from 14 farms in New South Wales, Australia and measured pasture biomass throughout 12 consecutive months using a calibrated rising plate meter (RPM) as well as pasture biomass estimated using a DST based on high temporal/spatial resolution satellite images were available. Data were balanced according to farm and week of each month and randomly allocated for model evaluation (20%) and for progressive training (80%) as follows: 25% training subset (1W: week 1 in each month); 50% (2W: week 1 and 3); 75% (3W: week 1, 3, and 4); and 100% (4W: week 1 to 4). Pasture biomass estimates using the DST across all training datasets were evaluated against a calibrated rising plate meter (RPM) using mean-absolute error (MAE, kg DM/ha) among other statistics. Tukey's HSD test was used to determine the differences between MAE across all training datasets. Relative to the control (no training, MAE: 498 kg DM ha-1) 1W did not improve the prediction accuracy of the DST (P > 0.05). With the 2W training dataset, the MAE decreased to 342 kg DM ha-1 (P < 0.001), while for the other training datasets, MAE decreased marginally (P > 0.05). This study accounts for minimal training data for a machine-learning DST to monitor pastures from satellites with comparable accuracy to a calibrated RPM which is considered the 'gold standard' for pasture biomass monitoring.

Near-infrared spectroscopy analysis of blood plasma for predicting nonesterified fatty acid concentrations in dairy cows

During the transition period, dairy cows are often exposed to negative energy balance (NEB), leading to lipid mobilization from adipose tissue into nonesterified fatty acids (NEFA), a common indicator of heightened illness risk. This study aimed to use blood near-infrared (NIR) spectra data to classify NEB into high or low categories, based on early-lactation cow NEFA thresholds. We collected a total of 186 plasma samples from 100 Holstein cows. The samples were categorized into critical thresholds, based on previous literature, of ≥0.60 and ≥0.70 mEq/L for identifying high NEB. Spectral data were preprocessed before the development of the predictive modes, which included the implementation of multiplicative scatter correction, standard normal variate (SNV), and first and second derivatives. The classification was performed using partial least square discriminant analyses (PLS-DA), and predictive performance was assessed using leave-one-out cross-validation. Predictive quality for each class was evaluated through specificity, precision, sensitivity, and F1 score. The study showed promising results, with the SNV technique achieving higher F1 scores. The model found 72.7% specificity, 78.9% precision, 80.8% sensitivity, and 79.8% F1 score to classify animals with NEFA levels of ≥0.60 mEq/L, and 82.1% specificity, 78.7% precision, 80.8% sensitivity, and 79.7% F1 score to classify animals with NEFA levels ≥0.70 mEq/L. These results indicate that NIR spectroscopy could serve as a tool for detecting cows under severe NEB, also showing potential for broader application across the entire transition period, as the spectral signal carried relevant information regarding cow metabolism. Furthermore, the combination of predictors derived from plasma spectra and other cow-level information can lead to more accurate disease alerts, given their relationship with the NEB.

Can the Inclusion of Forage Chicory in the Diet of Lactating Dairy Cattle Alter Milk Production and Milk Fatty Acid Composition? Findings of a Multilevel Meta-Analysis

In traditional ryegrass/white clover (Lolium perenne L./Trifolium repens L.) pastoral systems, forage herbs such as chicory (Cichorium intybus L.) present an opportunity to fill feed deficits during late spring and summer. Although multiple research publications have evaluated the efficacy of chicory for enhancing milk production and milk fatty acid (FA) profile, no publication has quantitatively synthesised the body of research. This systematic review and meta-analysis examined the effect of chicory on milk production and composition, as well as on the milk fatty acid composition of dairy cattle. A total of 29 comparisons from 15 unique research publications involving 597 dairy cattle were used to develop a dataset for analysis. Three-level random-effect and robust variance estimator models were used to account for the hierarchical structure of the data and the dependency of effect sizes within publications. Chicory inclusion increased milk yield when compared to grass-based diets {weighted mean difference (WMD) = 1.07 (95% CI 0.54-1.60) kg/cow/d, p < 0.001}, but it provided a similar milk yield when compared to other forages such as legumes and herbs {dicots; WMD = -0.30, (95% CI -89-0.29) kg/cow/day, p = 0.312}. Increases in milk yield were congruent with differences in DM intake (p = 0.09) and ME intakes (p = 0.003), being similar in chicory-fed and dicot-fed cows but higher than grass-fed cows. Chicory feeding's effect on milk solids was twice as high during mid lactation {154 days in milk; WMD = 0.13, (95% 0.081-0.175) kg/cow/day, p < 0.001} as during late lactation {219 days in milk; WMD = 0.06, (95% 0.003-0.13) kg/cow/day, p = 0.041}. In line with milk yield, greater and more significant effect sizes were found for alpha linolenic acid {ALA; WMD = 0.20 (95% CI 0.06-0.35) g/100 g FA, p = 0.011} when chicory was compared to grass species only. Comparing chicory with dicots suggests that chicory inclusion did not impact ALA concentrations {WMD = 0.001 (95% CI -0.02-0.2) g/100 g FA, p = 0.99}. There were no differences in conjugated linoleic acid concentration in the milk of cows fed chicory or control diets. The study provides empirical evidence of chicory's efficacy for improved milk production and milk fatty acid composition.

Caciocavallo Podolico Cheese, a Traditional Agri-Food Product of the Region of Basilicata, Italy: Comparison of the Cheese's Nutritional, Health and Organoleptic Properties at 6 and 12 Months of Ripening, and Its Digital Communication

Traditional agri-food products (TAPs) are closely linked to the peculiarities of the territory of origin and are strategic tools for preserving culture and traditions; nutritional and organoleptic peculiarities also differentiate these products on the market. One such product is Caciocavallo Podolico Lucano (CPL), a stretched curd cheese made exclusively from raw milk from Podolian cows, reared under extensive conditions. The objective of this study was to characterise CPL and evaluate the effects of ripening (6 vs. 12 months) on the quality and organoleptic properties, using the technological "artificial senses" platform, of CPL produced and sold in the region of Basilicata, Italy. Additionally, this study represents the first analysis of cheese-related digital communication and trends online. The study found no significant differences between 6-month- and 12-month-ripened cheese, except for a slight increase in cholesterol levels in the latter. CPL aged for 6 and 12 months is naturally lactose-free, rich in bioactive components, and high in vitamin A and antioxidants and has a low PUFA-n6/n3 ratio. The "artificial sensory profile" was able to discriminate the organoleptic fingerprints of 6-month- and 12-month-ripened cheese. The application of a socio-semiotic methodology enabled us to identify the best drivers to create effective communication for this product. The researchers recommend focusing on creating a certification mark linked to the territory for future protection.

N-3 Polyunsaturated Fatty Acids as a Nutritional Support of the Reproductive and Immune System of Cattle-A Review

This paper focuses on the role of n-3 fatty acids as a nutrient crucial to the proper functioning of reproductive and immune systems in cattle. Emphasis was placed on the connection between maternal and offspring immunity. The summarized results confirm the importance and beneficial effect of n-3 family fatty acids on ruminant organisms. Meanwhile, dietary n-3 fatty acids supplementation, especially during the critical first week for dairy cows experiencing their peripartum period, in general, is expected to enhance reproductive performance, and the impact of its supplementation appears to be dependent on body condition scores of cows during the drying period, the severity of the negative energy balance, and the amount of fat in the basic feed ration. An unbalanced, insufficient, or excessive fatty acid supplementation of cows' diets in the early stages of pregnancy (during fetus development) may affect both the metabolic and nutritional programming of the offspring. The presence of the polyunsaturated fatty acids of the n-3 family in the calves' ration affects not only the performance of calves but also the immune response, antioxidant status, and overall metabolism of the future adult cow.

Impact of varying levels of pasture allowance on the nutritional quality and functionality of milk throughout lactation

The objective of this study was to examine the impact of increasing proportions of grazed pasture in the diet on the composition, quality, and functionality of bovine milk across a full lactation. Fifty-four spring-calving cows were randomly assigned to 1 of 3 groups (n = 18), blocked on the basis of mean calving date (February 15, 2020 ± 0.8 d), pre-experimental daily milk yield (24.70 ± 3.70 kg), milk solids yield (2.30 ± 0.27 kg), lactation number (3.10 ± 0.13), and economic breeding index (182 ± 19). Raw milk samples were obtained weekly from each group between March and November 2020. Group 1 (GRS) consumed perennial ryegrass and was supplemented with 5% concentrates (dry matter basis); group 2 was maintained indoors and consumed a total mixed ration (TMR) diet consisting of maize silage, grass silage, and concentrates; and group 3 consumed a partial mixed ration diet (PMR), rotating between perennial ryegrass during the day and indoor TMR feeding at night. Raw milk samples consisted of a pooled morning and evening milking and were analyzed for gross composition, free amino acids, fatty acid composition, heat coagulation time, color, fat globule size, and pH. The TMR milks had a significantly higher total solids, lactose, protein, and whey protein as a proportion of protein content compared with both GRS and PMR milks. The GRS milks demonstrated a significantly lower somatic cell count (SCC), but a significantly higher pH and b*-value than both TMR and PMR milks. The PMR milks exhibited significantly lower total solids and fat content, but also demonstrated significantly higher SCC and total free amino acid content compared with GRS and TMR. Partial least squares discriminant analysis of fatty acid profiles displayed a distinct separation between GRS and TMR samples, while PMR displayed an overlap between both GRS and TMR groupings. Variable importance in projection analysis identified conjugated linoleic acid cis-9,trans-11, C18:2n-6 cis, C18:3n-3, C11:0, and C18:2n-6 trans as the largest contributors to the variation between the diets. Milk fats derived from GRS diets exhibited the highest proportion of unsaturated fats and higher unsaturation, health-promoting, and desaturase indices. The lowest proportions of saturated fats and the lowest atherogenic index were also exhibited by GRS-derived milk fats. This work highlights the positive influence of grass-fed milk for human consumption through its more nutritionally beneficial fatty acid profile, despite the highest milk solid percentages derived from TMR feeding systems. Furthermore, this study demonstrates the proportional response of previously highlighted biomarkers of pasture feeding to the proportion of pasture in the cow's diet.

Phenotypic variation in milk fatty acid composition and its association with stearoyl-CoA desaturase 1 (SCD1) gene polymorphisms in Gir cows

Individual variation in milk fatty acid (FA) composition has been partially attributed to stearoyl-CoA desaturase 1 (SCD1) gene polymorphisms in taurine breeds, but much less is known for Zebu breeds. This study investigated the phenotypic variation in milk FA composition, and the influence of SCD1 variants on this trait and on milk fat desaturase indices (DI) in Gir cows. The functional impact of SCD1 variants was predicted using bioinformatics tools. Milk and blood samples were collected from 312 cows distributed in 10 herds from five states of Brazil. SCD1 variants were identified through target sequencing, and milk FA composition was determined by gas chromatography. Phenotypic variation in milk FA composition fell within the range reported for taurine breeds, with SCD18 index showing the lowest variation among the DI. Fourteen SCD1 variants were identified, six of which not previously described. Regarding the A293V polymorphism, all cows were homozygous for the C allele (coding for alanine), whereas all genotypes were detected for the second SNP affecting the 293 codon (G > A), with compelling evidence for functional effects. Significant associations (based on raw p-values) were found between this SNP and C12:0, cis-9, trans-11 CLA and short-chain FA, and between another SNP (rs523411937) and C15:0 and odd-chain linear FA. A new SNP on Chr26:21277069 was associated with trans-11 C18:1, cis-9, trans-11 CLA, C18:3 n-3 and n-3 FA. These findings indicate that SCD1 polymorphisms also contributes to the phenotypic variation in milk FA composition of Gir cows, with potential use in their breeding programmes.

Effects of herbal supplements on milk production quality and specific blood parameters in heat-stressed early lactating cows

The present study explored the influence of supplemental herbal mixtures on cow milk production, quality, and blood parameters in dairy cows under high ambient temperatures. Thirty Holstein cows were randomly assigned into three experimental groups of 10 each. The first control group was supplied with the commercial basal diet, whereas two treatment groups were provided with the commercial basal diet supplemented with 50 and 100 g/head/day of the herbal mixture, respectively. The results showed that the mixture of herbal supplementation did not influence weekly milk production. Milk total fat, triglyceride, and total protein values were not affected (p < 0.05) in cows fed on basal diets supplemented with herbal mixture; however, milk cholesterol was decreased significantly by 100 mg/head/day of the herbal mixture. On the other hand, lactose has increased significantly by adding 100 mg/head/day of herbal mixture. Furthermore, the total cholesterol level in serum was decreased by adding 100 mg/head/day of the herbal mixture, while plasma prolactin, cortisol, GOT, and GPT were unaffected. Regarding fatty acids (C18, C18:1 (c9), 18:1 (c11), 18:2 (c9, c12), 18:2 (t9, t12), and CLA (c9, t11)), there was no significant variation between the groups. Meanwhile, both C19:00 and 18:3 (c6, c9, and c12) were noticeably higher (p < 0.05) in the group that received 100gm, followed by 50 mg, compared to the control. In conclusion, the supplement with a herbal mixture positively affected milk quality by decreasing total cholesterol and increasing lactose, milk fatty acid profile by increasing unsaturated fatty acids content, and plasma cholesterol levels.

Abomasal infusion of essential fatty acids and conjugated linoleic acid during late pregnancy and early lactation affects immunohematological and oxidative stress markers in dairy cows

Oxidative stress and inflammation, as natural parts of metabolic adaptations during the transition from late gestation to early lactation, are critical indicators of dairy cows' metabolic health. This study was designed to investigate the effects of abomasal infusion of essential fatty acids (EFA), particularly α-linolenic acid, and conjugated linoleic acid (CLA) on plasma, erythrocyte, and liver markers of oxidative stress in dairy cows during the transition period. Rumen-cannulated German Holstein cows (n = 38) in their second lactation (11,101 ± 1,118 kg milk/305 d, mean ± standard deviation) were abomasally infused with one of the following treatments from d -63 antepartum until d 63 postpartum (PP): CTRL (n = 9; 76 g/d coconut oil); EFA (n = 9; 78 g/d linseed plus 4 g/d safflower oil); CLA (n = 10; isomers cis-9,trans-11 and trans-10,cis-12 CLA; 38 g/d); and EFA+CLA (n = 10; 120 g/d). Hematological parameters as well as markers of oxidative status were measured in plasma, erythrocytes, and liver before and after calving. Immunohematological parameters, including erythrocyte number, hematocrit, hemoglobin, mean corpuscular hemoglobin, leukocytes, and basophils, were affected by time, and their peak levels were observed on the day after calving. The oxidative stress markers glutathione peroxidase 1 and reactive oxygen metabolites in plasma and erythrocytes were both affected by time, exhibiting the highest levels on d 1 PP, whereas β-carotene, retinol, and tocopherol were at their lowest levels at the same time. Immunohematological parameters were only marginally affected by fatty acid treatment in a time-dependent manner. As such, lymphocyte and atypical lymphocyte counts were both significantly highest in the groups that received EFA at d 1 PP. Moreover, EFA supplementation increased the mean corpuscular volume and showed a trend for induction of mean corpuscular hemoglobin compared with the CLA group during the transition period. The PP mean thrombocyte volume was higher in the EFA than in the CLA group (except for d 28) and both EFA and CLA reduced number of thrombocytes and thrombocrit at distinct time points. Hepatic mRNA abundance of markers related to oxidative status, including glutathione peroxidase (GPX-1) and catalase (CAT), was lower (P < 0.05) in EFA-treated than non-EFA-treated cows at d 28 PP. Dairy cows at the onset of lactation were characterized by induced markers of both oxidative stress and inflammation. Supplementing EFA and CLA had minor and time-dependent effects on markers of oxidative stress in plasma, erythrocytes, and liver. A comparison of EFA supplementation with CLA or CTRL showed higher immunohematological response at d 1 PP and lower hepatic antioxidant levels by d 28 PP. Supplementation with EFA+CLA had only a minor effect on oxidative markers, which were more similar to those with the EFA treatment. Altogether, despite the time-dependent differences, the current findings show only minor effects of EFA and CLA supplementation in the prevention of early lactation-induced oxidative stress.

Different Conditions during Confinement in Pasture-Based Systems and Feeding Systems Affect the Fatty Acid Profile in the Milk and Cheese of Holstein Dairy Cows

The diet of dairy cows influences the fatty acid (FA) profiles of their milk and cheese, but how these are affected by different conditions during confinement in a mixed system (MS:grazing + total mixed ration:TMR) is not known. The aim of this study was to compare the FAs of the milk and cheese from MS in a compost-bedded pack barns (CB-GRZ) versus an outdoor soil-bedded pen (OD-GRZ) during confinement, and with a confinement system (100%TMR) in a compost-bedded pack barns (CB-TMR). Individual milk samples (n = 12 cows/group), cheese, and pooled milk (MilkP) samples were collected. The saturated FA percentages in the milk and the omega 6/omega 3 ratio in the MilkP and cheese were greater for the CB-TMR (p < 0.0001), while the unsaturated and monounsaturated FA percentages in the milk were lower for the CB-TMR than the MS (p < 0.001). The milk n-3, C18:3, and conjugated linoleic acid percentages were lower for the CB-TMR than the MS (p < 0.001). The milk n-3 and C18:3 were higher for the CB-GRZ than the OD-GRZ (p < 0.01), but no differences were observed between the MS in the MilkP and cheese. In conclusion, CB-GRZ cows during confinement produced better quality milk compared to OD-GRZ cows. However, the FA profiles of the milk, MilkP, and cheese were affected to a greater extent by the feeding management than by the conditions during confinement.

Can botanically-diverse pastures positively impact the nutritional and antioxidant composition of ruminant meat? - Invited review

A desire for more sustainable pasture-based ruminant feeding systems has led to growing interest in utilising botanically-diverse pastures (BDP) over monoculture pastures. Research suggests that, from a human consumption viewpoint, grass-based ruminant feeding leads to more nutritionally desirable fatty acid (FA) and antioxidant concentrations in meat compared with concentrate feeding, which can affect meat quality. The FA, antioxidant and secondary metabolite content of plants differ, depending on species, maturity and seasonality, offering the potential through targeted feeding of BDP to produce meat with superior nutritional and antioxidant profiles. This review explores the effect, if any, that grazing ruminants on BDP has on the FA profile, fat-soluble vitamin, and antioxidant content of meat. The input-output relationship between forage and red meat constituents is complex and is likely affected by species diversity, forage consumption patterns and modulation of rumen fermentation processes. Further investigation is required to fully understand the effect that BDP may have on the composition and quality of ruminant meat.

Comparison of milk and grass composition from grazing Irish dairy herds with and without milk fat depression

BACKGROUND

This study investigated the factors relating to pasture chemical and fatty acid (FA) composition that influence the milk fat percentage of spring calving, grazing dairy cows. The relationship between milk fat percentage and FA composition of the milk in these herds was also investigated.

RESULTS

Milk protein percentage, milk casein percentage and cheddar cheese yield were increased in milk from HMF herds. Cows from LMF herds did not have negatively altered milk processability including rennet coagulation time (RCT), pH and ethanol stability. Crude protein, NDF, ADF, ether extract and total FA content of pasture was not different between LMF and HMF herds. Milk fat concentration of conjugated linoleic acid (CLA) t10, c12 was not different between HMF and LMF herds. Pre-grazing herbage mass and pasture content of crude protein, neutral detergent fibre (NDF) and total FA were similar between HMF and LMF herds. Pasture offered to LMF herds had a higher concentration of monounsaturated fatty acids (MUFA). A strong negative relationship (r = -0.40) was evident between milk fat percentage and pasture crude protein content for MMF herds (3.31-3.94% milk fat).

CONCLUSIONS

This research reports improved milk protein percentage, milk casein percentage and cheddar cheese yield from HMF herds compared to LMF herds. Milk processability was not impacted by low milk fat percentage. Pasture NDF and total fatty acid content was similar in HMF herds and LMF herds. Milk fat percentage had a strong negative association (r = -0.40) with pasture crude protein content in MMF herds (MF 3.31-3.94%). Correlation values between pasture chemical and FA composition and milk fat percentage in LMF herds and HMF herds were low, indicating that diet is not the only causative factor for variation in milk fat of grazing dairy cows. Comparison of milk fatty acid composition from herds with and without milk fat depression suggests that there may be other fatty acids apart from CLA t10, c12 that contribute to the inhibition of milk fat synthesis during milk fat depression in grazing herds.

Effect of Using Faba Bean and/or Italian Ryegrass in Total Mixed Rations to Dairy Cows

The livestock sector must find solutions to reduce the feeding costs and meet the challenge for a more sustainable production system in line with the European Green Deal requirements. The aim of this study was to evaluate the effect of including legume silage on voluntary intake in dairy cows, milk production, and composition. Three total mixed rations (TMR) based on faba bean (FB), Italian ryegrass (IR), or faba bean-Italian ryegrass intercrop (FBIR, 60:40) silages were used in feeding trials of dairy cows during two consecutive years. Nine Friesian cows were randomly allocated in three groups, following a 3 × 3 Latin square design with three diets for three periods. TMR were offered ad libitum in addition to eighteen hours of grazing daily and extra concentrate during milking. No differences were observed in dry matter intake. Diets did not affect milk production or composition, except for urea content, with a higher urea excretion in FB diet. Fatty acid profile was different in milk from cows feeding FB, with a significantly lower content of saturated fatty acids and a higher content of conjugated linoleic acid than milk produced with FBIR and IR diets.

Dairy Sheep Grazing Management and Pasture Botanical Composition Affect Milk Macro and Micro Components: A Methodological Approach to Assess the Main Managerial Factors at Farm Level

Simple Summary

Studies on the management factors that affect milk components at the farm level are important for understanding how to transfer the results from experimental study. Plant phenological stages and partially fresh herbage intakes affect the lactose and milk fatty acid profile. The botanical composition of the grassland partially affects the milk’s phenol content. A few small relationships between plant phenols and milk colour could be of interest to explain the changes in milk colour parameters.

Abstract

The fatty acid profile, vitamins A and E, cholesterol, antioxidant power colour and the phenols profile of Sarda sheep milk from 11 commercial sheep flocks managed under permanent grassland were investigated. In each farm, the structural and managerial data and milk samples were collected during four periods (sampling dates, SD): January, March, May, and July. Data from the milk composition (fat, protein, casein, lactose, and somatic cell count), 68 fatty acids, 7 phenols, 1 total gallocatechin equivalent, ferric reducing antioxidant power, vitamins A and E, cholesterol, degree of antioxidant protection, and the colour (b *, a * and L *) were analyzed by multivariate factorial analysis using a principal component analysis approach. A proc mixed model for repeated measurement to point out the studied factors affecting significant macro and micro milk composition was also used. Only the first five components were detailed in this paper, with approximately 70% of the explained variance detected. PC1 presented the highest positive loadings for milk lactose, de novo FA synthesis and the BH intermediate, whereas OBCFA had negative loadings values. The PC2, LCFA, UFA, MUFA, vitamins E, and DAP showed positive loadings values, while SFA had a negative value. The PC3 showed a high positive loading for total phenols and non-flavonoids. PC4 presented a high positive loading for the milk macro-composition and negative values for n-3 FAs. The PC5 is characterized by high positive loadings for the a * and L * colour parameters whereas negative loadings were detected for the milk flavonoids content. These preliminary results could help to establish future threshold values for the biomarkers in milk sourced from grazing dairy sheep in natural, permanent pasture-based diets.

The Effect of Sustainable Feeding Systems, Combining Total Mixed Rations and Pasture, on Milk Fatty Acid Composition and Antioxidant Capacity in Jersey Dairy Cows

This study was carried out to assess the effect of using pasture combined with total mixed ration (TMR) on milk production and composition, fatty acid (FA) profiles, fat-soluble antioxidant content, and total milk antioxidant capacity (TAC). In addition, the effect of milk pasteurization and storage at 2 °C for 4 days, lipophilic antioxidants and TAC were assessed. Two homogeneous groups of Jersey cows (n = 8) were constituted, which were randomly assigned to one of the two treatments: TMR (without access to pasture), or partial mixed diet (pTMR: grazing 8 h/day + TMR indoors). To establish FA profiles and lipophilic antioxidants’ changes in milk during the grazing period, in case of the pTMR group the experimental period was spilt in three grazing periods: P1 (May), P2 (June), and P3 (June/July). Milk yielded from cows having limited access on pasture (pTMR diet) showed an improved FA profile, with higher concentrations of FAs considered benefic for human health (vaccenic acid (VA), conjugated linoleic acid (CLA), omega-3 FA (n-3 FA)) (p < 0.01) and a lower concentration of FAs with hypercholesterolemiant potential (C12:0, C14:0, and C16:0) (p < 0.05), compared to that of the TMR diet. This change in FA profile was correlated with improved sanogenous lipid indices of milk fat (n-6/n-3 FA atherogenic index and thrombogenic index). Milk yielded during the P1 grazing period had higher concentrations of VA, CLA, and n-3 FA (p < 0.05) and lower concentrations of C14:0 and C16:0 (p < 0.01); it exhibited the best values for the main sanogenous fat lipid indices of fat. Moreover, pTMR milk showed a higher α-tocopherol, retinol, and β-carotene content (p < 0.05), positively correlated with TAC values in milk (P1 ˃ P2 ˃ P3). By comparison, cows fed using the TMR diet yielded a higher quantity of milk (p < 0.05), but a lower fat and protein content (p < 0.01), and also a higher saturated FAs and n-6 FA content (p < 0.05) together with a lower concentration of lipophilic antioxidants in milk. Thermal treatment showed no effect on α-tocopherol and retinol content in milk, but their concentrations decreased during the storage, at the same time a TAC decrease. The results of this study prove the positive effect of using pasture combined with TMR on FA profiles, milk antioxidant content, and antioxidant capacity, with beneficial effects on nutrition and health in humans.

Milk Fatty Acid Profile of Holstein Cows When Changed from a Mixed System to a Confinement System or Mixed System with Overnight Grazing

This study is aimed at comparing the milk fatty acid profile (FAP) of cows that changed from a mixed system (MS) of double grazing plus total mixed ration (TMR) to a total confinement system (TCS, 100% TMR) with cows that changed to another MS with one overnight grazing plus TMR and compare with cows that were kept unchanged in TCS. The diet change was made in the second month of lactation. The milk samples were collected at one (M1-spring) and three months of lactation (M3-summer). Three treatments are as follows (each n = 10): confined cows fed with TMR throughout the period (GTMR), cows that changed from MS with double grazing plus TMR in M1 to TCS in M3 (GCHD), and cows that changed from a MS with double grazing plus TMR in M1 to a MS with overnight grazing plus TMR in M3 (GTMR+P). Unlike GTMR+P, GCHD improved milk production after change (increased 14% from M1 to M3), but milk FAP was impaired. In M3, conjugated linoleic acid (C18 : 2-CLA) in GTMR and GCHD was lower than GTMR+P (p < 0.05), and linolenic (C18 : 3-n-3) was lower in GCHD than GTMR+P. Maintaining grazing in summer overnight sustained milk fat quality, evidenced by higher C18 : 3 (n-3); C18 : 2 (CLA); and n-6/n-3 ratio than cows that changed to TCS.

Pregnancy status predicted using milk mid-infrared spectra from dairy cattle

Accurate and timely pregnancy diagnosis is an important component of effective herd management in dairy cattle. Predicting pregnancy from Fourier-transform mid-infrared (FT-MIR) spectroscopy data is of particular interest because the data are often already available from routine milk testing. The purpose of this study was to evaluate how well pregnancy status could be predicted in a large data set of 1,161,436 FT-MIR milk spectra records from 863,982 mixed-breed pasture-based New Zealand dairy cattle managed within seasonal calving systems. Three strategies were assessed for defining the nonpregnant cows when partitioning the records according to pregnancy status in the training population. Two of these used records for cows with a subsequent calving only, whereas the third also included records for cows without a subsequent calving. For each partitioning strategy, partial least squares discriminant analysis models were developed, whereby spectra from all the cows in 80% of herds were used to train the models, and predictions on cows in the remaining herds were used for validation. A separate data set was also used as a secondary validation, whereby pregnancy diagnosis had been assigned according to the presence of pregnancy-associated glycoproteins (PAG) in the milk samples. We examined different ways of accounting for stage of lactation in the prediction models, either by including it as an effect in the prediction model, or by pre-adjusting spectra before fitting the model. For a subset of strategies, we also assessed prediction accuracies from deep learning approaches, utilizing either the raw spectra or images of spectra. Across all strategies, prediction accuracies were highest for models using the unadjusted spectra as model predictors. Strategies for cows with a subsequent calving performed well in herd-independent validation with sensitivities above 0.79, specificities above 0.91 and area under the receiver operating characteristic curve (AUC) values over 0.91. However, for these strategies, the specificity to predict nonpregnant cows in the external PAG data set was poor (0.002-0.04). The best performing models were those that included records for cows without a subsequent calving, and used unadjusted spectra and days in milk as predictors, with consistent results observed across the training, herd-independent validation and PAG data sets. For the partial least squares discriminant analysis model, sensitivity was 0.71, specificity was 0.54 and AUC values were 0.68 in the PAG data set; and for an image-based deep learning model, the sensitivity was 0.74, specificity was 0.52 and the AUC value was 0.69. Our results demonstrate that in pasture-based seasonal calving herds, confounding between pregnancy status and spectral changes associated with stage of lactation can inflate prediction accuracies. When the effect of this confounding was reduced, prediction accuracies were not sufficiently high enough to use as a sole indicator of pregnancy status.

Characterization of Fat Quality in Cow Milk from Alpine Farms as Influenced by Seasonal Variations of Diets

Simple Summary

Milk produced in Alpine farms under pasture- and-grass-based feeding systems is characterized by beneficial nutritional traits, which are linked to its high fat quality. In this study, milk samples collected in two alpine farms set in the Italian Piedmont region were analyzed together with samples of feedstuffs (pasture, fresh grass, concentrates and total mixed ration) furnished to cows during summer and winter, when the feeding strategy was modified. The results suggested a favorable fat composition of all samples analyzed, with some differences detected between the seasons and the farms. The milk obtained following a pasture- or fresh-grass-based feeding strategy (during summer) showed a higher fat quality, which was characterized by higher amounts of beneficial fatty acids. Particularly, a distinctive fat composition of milk samples coming from cows exclusively fed on pasture during the summer season was evidenced. The outcomes obtained in this study contributed toward evaluating and promoting alpine dairy products from the Alpine region as products associated with an added value, with beneficial effects for both producers and consumers.

Abstract

The production systems linked to mountain animal husbandry have had an environmental, social and cultural role in recent years. Zootechnical systems based on feeding strategies, such as pasture grazing and grass-fed strategies, contribute to a significant increase in the relative amounts of favorable fatty acids (FAs) in animal products, indicating their ability to improve the long-term health of consumers. In this study, we compared different feeding strategies in two small mountain farms in the Piedmont Alpine region, Italy. Particularly, during the summer season, the two farms were distinguished by the exclusive employment of Alpine pasture (farm A), assumed as the best way to improve the quality of the FA profile in milk vs. the supply of daily fresh cut mountain grass plus a reduced implementation with hay and concentrates directly in the barn (farm B). The milk fatty acid profile was analyzed using gas chromatography. The results showed the high quality of alpine milk collected in the two farms. Even with some differences, particularly evidenced when comparing the summer diets, the milk FA profiles in farm A and farm B were favorable from a nutritional point of view in both seasons. Milk samples obtained using the exclusive employment of alpine grazing during summer were represented by an FA profile of higher quality (lower saturated FAs, higher branched FAs and monounsaturated FA, favorable n6/n3 ratio). However, milk obtained using the integrated strategy (fresh grass plus concentrates in the barn farm B) resulted in a more homogenous composition during the summer season, with a higher concentration of polyunsaturated FAs. These outcomes suggested that the integrated strategy, even if related to a lower ability in improving milk FA profile, could represent a valid and cost-effective alternative for mountain farmers to obtain an overall superior quality of milk, which was not strictly linked to the grazing practice. The multivariate analysis showed that information contained in the milk FA profile may provide a valuable tool that can distinguish mountain-grass-based diet.

Influence of the Type of Silage in the Dairy Cow Ration, with or without Grazing, on the Fatty Acid and Antioxidant Profiles of Milk

Dairy systems based on grass and forages are widely spread throughout the European Atlantic Arc and they have an influence on milk quality. Likewise, legumes are a key element in the farms to improve cows’ diet and farm feed self-sufficiency. The aim of this study was to evaluate the effect of the legumes in the diet and the feeding system (pasture-based vs. confined) on milk production and composition. An assay was performed with 18 Friesian cows randomized into two management groups (grazing or confined). Three total mixed rations based on Italian ryegrass, faba bean or field pea silages were offered ad libitum for nine continuously housed cows or during two hours after each milking for another nine grazing cows. Regardless of type of silage, grazing cows had higher dry matter intake and milk production than confined cows. Likewise, grazing cows produced milk with a lower concentration of protein and urea than confined cows. The dairy cows fed total mixed rations based on both legume silages had a milk fat with a higher proportion of unsaturated fatty acids, especially with the inclusion of faba bean silage in the diet. The results demonstrate that the profile of fatty acids and antioxidants is related to the feeding system in dairy cows. Grazing directly influenced the composition of milk, decreasing the proportion of saturated fatty acids and increasing the content of unsaturated fatty acids, as CLA, and the antioxidants, as lutein and β-cryptoxanthin.

Multivariate modelling of milk fatty acid profile to discriminate the forages in dairy cows' ration

Although there are many studies on the importance of fatty acids (FA) in our diet and on the influence of dairy diets on FA metabolism, only a few investigate their predictive capacity to discriminate the type, amount and conservation method of farm forages. This research quantifies differences in milk FA concentrations and, using a supervised factorial discriminant analysis, assesses potential biomarkers when replacing maize with other silages, grass/lucerne hays or fresh grass. The statistical modelling identified three main clusters of milk FA profiles associated with silages, hays and fresh grass as dominant roughages. The main implication of a dairy cow feeding system based on poliphytic forages from permanent meadows is enhancing milk’s nutritional quality due to an increase in beneficial omega-3 polyunsaturated FA, conjugated linoleic acids and odd chain FA, compared to feeding maize silage. The study also identified a small but powerful and reliable pool of milk FA that can act as biomarkers to authenticate feeding systems: C16:1 c-9, C17:0, C18:0, C18:3 c-9, c-12, c-15, C18:1 c-9, C18:1 t-11 and C20:0.

In vitro Fermentation Profile and Methane Production of Kikuyu Grass Harvested at Different Sward Heights

Highly digestible forages are associated with an in vitro low-methane (CH4) rumen fermentation profile and thus the possibility of reducing CH4 emissions from forage-based systems. We aimed to assess the in vitro ruminal fermentation profile, including CH4 production, of the top stratum of Kikuyu grass (Cenchrus clandestinus - Hochst. ex Chiov) harvested at different sward heights (10, 15, 20, 25, and 30 cm). Herbage samples (incubating substrate) were analyzed for their chemical composition, in vitro organic matter digestibility (IVOMD), and morphological components. In vitro incubations were performed under a randomized complete block design with four independent runs of each treatment. Gas production (GP), in vitro dry matter digestibility (IVDMD), CH4 production, total volatile fatty acid (VFA) concentration, and their acetate, propionate, and butyrate proportions were measured following 24 and 48 h of incubation. Herbage samples had similar contents of organic matter, neutral detergent fiber, and crude protein for all treatments. However, a higher acid detergent fiber (ADF) content in taller sward heights than in smaller sward heights and a tendency for metabolizable energy (ME) and IVOMD to decrease as sward height increased were found. Similarly, the stem + sheath mass tended to increase with increasing sward height. Amongst the nutrients, ME (r = −0.65) and IVDMD (r = −0.64) were negatively correlated with sward height (p &lt; 0.001) and ADF was positively correlated with sward height (r = 0.73, p &lt; 0.001). Both the GP and IVDMD were negatively related to the sward height at both incubation times. Sward heights of Kikuyu grass below 30 cm display an in vitro profile of VFAs high in propionate and low in acetate, with a trend toward lower methane production of CH4 per unit of IVDMD. These findings are important to aid decision-making on the optimal sward height of Kikuyu grass and manage animal grazing with the opportunity to reduce CH4 production.

Mineral Concentrations in Bovine Milk from Farms with Contrasting Grazing Management

Thirty conventional and twenty-four organic dairy farms were divided into equal numbers within system groups: high-pasture, standard-pasture, and low-pasture groups. Milk samples were collected monthly for 12 consecutive months. Milk from high-pasture organic farms contained less fat and protein than standard- and low-pasture organic farms, but more lactose than low-pasture organic farms. Grazing, concentrate feed intake and the contribution of non-Holstein breeds were the key drivers for these changes. Milk Ca and P concentrations were lower in standard-pasture conventional farms than the other conventional groups. Milk from low-pasture organic farms contained less Ca than high- and standard-pasture organic farms, while high-pasture organic farms produced milk with the highest Sn concentration. Differences in mineral concentrations were driven by the contribution of non-Holstein breeds, feeding practices, and grazing activity; but due to their relatively low numerical differences between groups, the subsequent impact on consumers' dietary mineral intakes would be minor.

Daytime Grazing in Mountainous Areas Increases Unsaturated Fatty Acids and Decreases Cortisol in the Milk of Holstein Dairy Cows

The effects of grazing lactating cows in mountainous areas for 12 and 24 h compared with the confined indoor system were evaluated by examining the overall milk fatty acid and cortisol. Twenty-one dairy cows were allocated to three treatment groups: (1) control (confined management system in a free-stall barn; TMR based), (2) grazing for 12 h (12 hG; TMR plus grazing pasture), and (3) grazing for 24 h (24 hG; pasture-based feeding system). Dry matter intake was higher in the control and 12 hG groups than in the 24 hG group. The yields of total milk and the 3.5% fat-corrected milk were the lowest in the 24 hG group. Milk fat was the highest in the 24 hG group and higher in 12 hG compared with the control group. Milk protein and lactose levels were the highest in the 12 hG group. The highest somatic cell count was observed in the 24 hG group. The saturated fatty acid levels were higher in the control group compared with the 12 hG and 24 hG groups. There was no difference in overall mono-unsaturated fatty acids between 12 hG and 24 hG groups. Poly-unsaturated fatty acids were higher in the 12 hG group compared with the control and 24 hG groups. There was no difference in omega-6 (ω-6) fatty acids among the groups, and omega-3 fatty acids were higher in the 12 hG group than in the control group. Milk cortisol was the highest in the 24 hG group and higher in the control group compared with the 12 hG group. Taken together, grazing for 12 h is advisable for farms that have access to mountainous areas to improve the milk fatty acid profile and decrease the stress levels in high-yielding Holstein lactating cows.

Effects of Pasture Type on Metabolism, Liver and Kidney Function, Antioxidant Status, and Plant Secondary Compounds in Plasma of Grazing, Jersey Dairy Cattle During Mid-lactation

Some pasture species are rich in phytochemicals, able to improve milk yield and quality and to reduce the environmental impacts of livestock farming. The phytochemicals interact with the different gene networks within the animal, such as nuclear factor erythroid 2-related factor 2 (NRF2), but their overall impact on animal health remains to be fully understood. The objective of this study was to identify the effects of pasture Legumes and non-leguminous Forbs containing high bioactive compounds on metabolism and activity of the liver, antioxidant response, kidney function, and inflammation of dairy cows using a large array of blood parameters associated with metabolism and the innate immune system. For this purpose, 26 parameters and the concentration of certain bioactive compounds were assessed in blood plasma, collected from the Jersey cows grazing either Grass, Legume, or Forb-based pastures. In addition, serum collected from all the cows was utilized to detect the changes in NRF2 activation in bovine mammary alveolar cells (MACT) and hepatocytes. Compared with Grass, the cows that grazed both Forb and Legume pastures had lower β-hydroxybutyric acid (BHB) and creatinine and larger vitamin E and the ferric reducing ability of the plasma, supporting an improved antioxidative status for these animals. Compared with both Grass and Legume, the cows that graze Forb pasture had lower urea and urea to creatinine ratio, and lower creatinine, indicating a better kidney function. The cows grazing Legume pasture had greater hematocrit, bilirubin, cholesterol, albumin, β-carotene, retinol, and thiol groups but lower ceruloplasmin, paraoxonase, and myeloperoxidase (MPO) than those grazed Grass and Forb pastures, indicating a positive effect of Legume pasture on the liver, oxidative stress, and red blood cells. The plasma of cows in the various pastures was enriched with various isoflavonoids, especially the cows grazed on Forb and Legume pastures, which likely contributed to improving the antioxidative status of those cows. However, this effect was likely not due to the higher activation of NRF2. Overall, these results indicate that Forb and Legume pastures rich in secondary metabolites do not strongly affect the metabolism but can improve the status of the liver and the kidney and improve the efficiency of N utilization and antioxidant response, compared with the Grass pasture.

A quantitative review of on-farm feeding practices to enhance the quality of grassland-based ruminant dairy and meat products

In the last decades, a large body of evidence has highlighted the major role of feeding management practices in improving specific nutritional, technological and sensory quality traits of ruminant products. However, results have been mostly obtained under controlled conditions, and have been rarely validated on-farm. Therefore, a quantitative review was conducted to quantify the effects of on-farm feeding management practices on carotenoids, fat-soluble vitamins, colour, fatty acids (FAs), terpenes and sensory properties in the main animal product categories (PCs): dairy products from cattle (DC), sheep (DS) and goat (DG), and meat from cattle (MC) and sheep (MS). Four feeding scenarios were selected according to the consistency of on-farm studies in the literature: (a) feeding "Fresh herbage" instead of conserved forages; (b) ban any form of silage ("Silage-free"); (c) ban maize silage ("Maize silage-free"); (d) feeding forages from permanent grasslands rich in species or plant secondary metabolites (PSMs) ("PSM-rich permanent grassland"). Feeding fresh herbage increased the concentration of carotenoids, fat-soluble vitamin, n-3 FA, rumenic acid, and branched chain FA (BCFA), and reduced the concentration of saturated FA, for all PC, with overall stronger effect for dairy products than for meat. The texture of meat and dairy products was marginally affected, whereas feeding fresh herbage decreased lactic and increased vegetal notes in DC. The "Silage-free" feeding scenario resulted in increased vaccenic acid, rumenic acid, BCFA, and C18:3n-3 in DC. The "Maize silage-free" feeding scenario lowered n-6 FA whereas increased n-3, rumenic acid and BCFA concentrations in DC. Feeding ruminants with forages from "PSM-rich permanent grasslands" increased monounsaturated FA, n-3 FA and rumenic acid and decreased n-6 FA in dairy products, and only marginally affected meat FA composition. The DC from "PSM-rich permanent grasslands" showed higher intense, spicy and animal notes. Overall, the differences between feeding management practices observed on farm were smaller than those observed under controlled trials. Several confounding factors, not controlled when operating under on-farm conditions, could be at the origin of these divergences (i.e. mixed diets, forage characteristics, animal-related factors). This review confirmed that farming practices may differently affect several quality traits of ruminant products. It also highlighted the uneven knowledge on the effect of feeding management depending on the PC: larger for milk than for meat and decreasing when moving from cattle to sheep and from sheep to goat.

Nutrient utilization, performance, and milk fatty acid composition of grazing cows fed supplements with babassu coconut

This study evaluated the effects of dietary inclusion of cracked babassu coconut (CBC) in the supplement on nutrient utilization, performance, and milk fatty acid (FA) composition of dairy cows grazing Megathyrsus maximus cv. Mombasa. Five multiparous Holstein × Zebu mid-lactation cows (125 ± 16.5 days in milk) were assigned to five dietary treatments (replacement of 0%, 20%, 40%, 60%, and 80% of ground corn with CBC, on a dry matter (DM) basis) in a 5 × 5 Latin square design. The intake of DM from the supplement, crude protein (CP), non-fiber carbohydrate (NFC), fat (ether extract (EE)), and total digestible nutrients (TDNs) decreased linearly (P < 0.05), while the intake of DM from forage increased linearly (P < 0.05), with the increase in CBC inclusion in the supplement. Conversely, total DM intake was unaffected (P > 0.05). The DM, NFC, EE, and TDN digestibility decreased linearly (P < 0.05), while organic matter (OM) digestibility decreased in a quadratic fashion (P < 0.05), as CBC inclusion in the supplement increased. Nevertheless, digestibility of CP was unaffected (P > 0.05). Milk yield and composition (lactose, fat, protein, casein, and majority of FA) showed a linearly decreasing pattern (P < 0.05) with the increasing of CBC inclusion. However, proportions of trans-vaccenic acid, rumenic acid, total monounsaturated FA, and odd- and branched-chain FAs increased linearly (P < 0.05). On the opposite, total saturated FA (SFA) and the n-6:n-3 FA ratio in milk fat decreased linearly (P < 0.01). Hence, replacement of corn meal with CBC up to 80% in the supplement decreases nutrient intake and digestibility, as well as milk yield response in grazing dairy cows. However, CBC inclusion may enhance the nutritional properties of milk fat.

The effect of feeding whole-crop barley or black oat silage in the fatty acid content of milk from cows in small-scale dairy systems in the highlands of Mexico

Diets have an important effect on the fatty acid (FA) content in milk from dairy cows so that feeding strategies may modify the FA profile. There is little information on the fatty acid contents of whole-crop barley (BLY) and black oat (BKO) silages and on milk from cows fed these silages that are an alternative forage for small-scale dairy systems (SSDS). Given the growing interest in foods with favourable health attributes, the objective was to identify the FA content of milk from dairy cows fed whole-crop BLY and BKO silages in small-scale systems. Three inclusion levels of BLY and BKO silage were assessed in nine lactating cows at pasture for 8 h/day and supplemented with 4.6 kg/DM/cow/day commercial concentrate. Treatments were BLY: 10 kg DM/cow/day BLY silage; BKO: 10 kg DM/cow/d BKO silage; and BLY/BKO: 5 kg BLY and 5 kg DM/cow/d BKO silages (50:50). A 3 × 3 Latin square design repeated three times with nine cows and 14-day periods was utilised. Variables evaluated were the content of fatty acids present in feeds and milk. Contents of linoleic (C18:2n-6) and linolenic (C18:3n-3) acids, as precursors of polyunsaturated fatty acids, were 46 in BLY and 50 BKO g/100 g, lower than for multispecies pasture (61 g/100 g). There were statistical differences in the content of short-chain fatty acids in milk (P < 0.05), being lower for BLY (18.9 g/100 g) compared with BKO (20.4 g/100 g) and BLY/BKO (20.6 g/100 g), the saturated fatty acids and linoleic acid (C18:2n-6c) were higher in BLY/BKO in relation to BLY and BKO. Content of health-promoting polyunsaturated fatty acids in milk was higher in BLY/BKO (P < 0.05). There were no differences (P < 0.05) in the atherogenic index, with values within reports. Small-grain cereal forages may produce milk with a favourable fatty acid content for human health.

Carvalho PC. Low-Intensity, High-Frequency Grazing Positively Affects Defoliating Behavior, Nutrient Intake and Blood Indicators of Nutrition and Stress in Sheep

The intensity and frequency of grazing affect the defoliating strategy of ruminants, their daily nutrient intake, thus nutrition and physiological status. Italian ryegrass (Lolium multiflorum Lam.) pastures were grazed by sheep either under a low-intensity/high-frequency grazing strategy (Rotatinuous stocking; RN) with nominal pre- and post-grazing sward heights of 18 and 11 cm, respectively, or under a high-intensity/low-frequency strategy (traditional rotational stocking; RT) with nominal pre- and post-grazing sward heights of 25 and 5 cm, respectively. Treatments were arranged under a complete randomized design and evaluated over two periods, in different years. In 2017, the aim was to depict the type of bites that sheep perform during the grazing-down and associate them to the grazing management strategy according to their relative contribution to the diet ingested. In 2018 we estimated the total nutrient intake and evaluated blood indicators of the nutritional status and immune response to stress of sheep. The bite types accounting the most for the diet ingested by RN sheep were those performed on the "top stratum" of plants with around 20, 15, and 25 cm, whereas the type of bites accounting the most for the diet of RT sheep were those performed on "grazed plants" with around 10, 5, and ≤ 3 cm. In 2018, the RN sheep increased by 18% the total organic matter (OM) intake and by 20-25% the intake of soluble nutrients (i.e., crude protein, total soluble sugars, crude fat), digestible OM and of metabolizable energy, and had 17.5, 18, and 6.1% greater blood concentration of glucose, urea nitrogen (BUN) and albumin, respectively, but 17% lower blood neutrophil-to-lymphocyte (N:L) ratio. Sheep grazing vegetative Italian ryegrass pastures under the low-intensity/high-frequency grazing strategy (RN) ingested a diet of better quality from bites allocated on the top stratum of plants, had greater intake of soluble nutrients and blood parameters positively associated with nutritional status and immune response to stress.

Metabolomic and Lipidomic Approaches to Evaluate the Effects of Eucommia ulmoides Leaves on Milk Quality and Biochemical Properties

Eucommia ulmoides leaves (EUL) contain a variety of natural bioactive compounds including chlorogenic acid, geniposide acid, and aucubin. These bioactive chemicals improve immune function and regulate lipid metabolism. The aim of this study was to investigate the effects of EUL on the biochemical properties of milk. Twenty Holstein dairy cows were randomly allocated to two groups fed a control (CTR, diet without EUL, n = 10) or EUL (diet containing 3% EUL, dry matter, n = 10) diet for 55 d. At the end of the experimental period (d 55), milk samples were collected and analyzed to determine their composition. Though levels of milk fat, protein, lactose, and total milk solids were similar between the groups, small molecules, metabolites, lipids, and cytokines differed. Compared with the CTR group, the EUL group had an improved cluster of differentiation (CD)4/CD8 ratio (P < 0.05) and lower interleukin (IL)-8 and IL-6 content (P < 0.05). Metabolomics analysis identified 14 metabolites including 7Z, 10Z, 13Z, 16Z, 19Z-docosapentaenoic acid (FC = 3.129), adrenic acid (FC = 2.830), and eicosapentaenoic acid (FC=1.685) as having significantly increased in the EUL group (P < 0.05) while 11 metabolites, including indole-2-carboxylic acid (FC = 0.636), cholic acid (FC = 0.430), and creatine (FC = 0.784) had significantly decreased (P < 0.05). Based on a constructed metabolome map, linoleic acid metabolism had the highest impact value for EUL. A total of 21 lipid classes and 1,094 lipid species were detected in the milk by lipidomic analysis, among which 40 differed significantly between the CTR and EUL groups. The present findings showed that the EUL altered milk composition. Correlation analysis showed that 7Z, 10Z, 13Z, 16Z, 19Z-docosapentaenoic acid, adrenic acid, and eicosapentaenoic acid levels were negatively correlated with those of the inflammatory factors IL-6 and IL-8 (P < 0.05), indicating that EUL improved milk quality by reducing inflammatory factors and increasing the CD4/CD8 ratio. Overall, our data demonstrate that EUL had positive effects on milk antioxidant parameters, immune indices, and micro-composition metabolism, thereby improving milk quality.

Corn-Soybean Intercropping Improved the Nutritional Quality of Forage Cultivated on Podzols in Boreal Climate

Intercropping systems could be a potential source of nutrient-rich forage production in cool climates on podzolic soils common in boreal ecosystems. In this study, we evaluated the effects of corn-soybean intercropping (IC) on the nutritional quality of forage. Two silage corn varieties were cultivated as monocropping (MC) or were intercropped with three forage soybean varieties using a randomized complete block design. IC significantly increased the crude protein (22%) and decreased the acid detergent (14%) and neutral detergent (6%) fibers. Forage net energy, total digestible nutrients, ash, dry matter intake, digestible dry matter and relative feed value were also significantly increased (p ≤ 0.05) in the IC treatments compared to corn MC. The macro and micro nutrients were higher in IC than corn MC. Intercropping increased the omega 3 fatty acid (FA) contents (67%) compared to corn MC. IC also increased the active microbial community in the plant root zone, which may contribute to the improvement in forage nutritional quality because the active soil microbial community composition showed significant correlations with soluble sugars, soluble proteins and potassium contents of the forage. These results demonstrate that corn-soybean IC could be a suitable cropping system to increase the nutritional quality of forage cultivated on podzols in boreal climates. The resultant forage has the potential to be a source of high-value animal feed for livestock production in cool climate regions of the world.

Invited review: A 2020 perspective on pasture-based dairy systems and products

Grazing pasture is the basis for dairy production systems in regions with temperate climates, such as in Ireland, New Zealand, parts of Australia, the United States, and Europe. Milk and dairy products from cows on pasture-based farms predominantly consuming fresh grazed grass (typically classified as "grass-fed" milk) have been previously shown to possess a different nutrient profile, with potential nutritional benefits, compared with conventional milk derived from total mixed ration. Moreover, pasture-based production systems are considered more environmentally and animal welfare friendly by consumers. As such, there is significant potential for market capitalization on grass-fed dairy products. As competition in this space increases, the regulations of what constitutes as grass-fed vary between different regions of the world. With this in mind, there is a need for clear and independently accredited grass-fed standards, defining the grass-fed criteria for labeling of products as such, subsequently increasing the clarity and confidence for the consumer. This review outlines the numerous effects of pasture production systems on dairy product composition, nutritional profile, and sustainability, and highlights potential future methods for authentication.

Milk fatty acid profile in cows as influenced by diet supplementation with rapeseed pomace and extruded full-fat soya in different feeding periods

The aim of the study was to estimate the effect of rapeseed pomace and extruded full-fat soya in the diets of dairy cows on changes in the milk fatty acid (FA) profile. The experiment was carried out on 30 dairy cows and divided into two periods: the indoor feeding period and the grazing period. Control diet cows were fed the farm’s total mixed ration (TMR); cows of experimental group 1 (ES) cows were fed the farm’s TMR supplemented with extruded full-fat soya; cows of experimental group 2 (RP) were fed the farm’s TMR supplemented with rapeseed pomace. The total content of saturated fatty acids (SFAs) tended to be lower in the RP and ES groups than in the control group during both feeding periods. Our results suggest that supplementing diets with rapeseed and soybean products are both effective in improving the fatty acid proportion of desirable (hypocholesterolaemic) FAs, mainly oleic acid (18:1n-9), linoleic acid (18:2n-6) and conjugated linoleic acid (CLAcis9trans11). The study showed that during the indoor feeding period, the unsaturated fatty acid (UFA) contents were significantly higher in the ES group compared to the control group (P < 0.05). The nutritional value of milk from the feeding groups in which rations were supplemented with ES or RP was better due to a quartile reduction of the atherogenicity index (AI) and the significantly increased spreadability index (SI) of the butter manufactured during the indoor feeding period (P < 0.01).

Kikuyu grass in winter-spring time in small-scale dairy systems in the highlands of central Mexico in terms of cow performance and fatty acid profile of milk

The work herein reported closes the evaluation of the role of kikuyu grass in small-scale dairy systems in the highlands of Mexico. The objective was to compare the productive response of vacas lecheras en pastoreo continuo de kikuyu (Cenchrus clandestinus) with a sown frost-resistant tall fescue (Lolium arundinaceum) during the winter-spring dry season in dairy systems and determine the fatty acid profile of feeds and milk. An on-farm double cross-over experiment with three periods the 14 days each was undertaken with eight Holstein cows randomly assigned to treatments sequence. Treatments were daytime grazing for 8 h/d of a Cajun II endophyte free tall fescue pasture invaded by kikuyu grass (CJ) or a naturally invaded kikuyu grass pasture (KY), both associated with white clover (Trifolium repens) and annual ryegrass (Lolium multiflorum). Cows were supplemented in pens with 6.0 kg DM/cow/day with maize silage and 4.6 kg DM/cow/day of commercial concentrate. The fatty acid profiles of feeds and milk were determined by gas chromatography. There were differences (P<0.05) for net herbage accumulation and chemical composition between pastures, but not for in vitro digestibility or estimated metabolizable energy. In animal variables, protein content in milk was higher in KY (P<0.05). There were significant differences (P<0.05) among experimental periods for milk fat content and milk urea nitrogen with the highest values in Period 3. Pasture DM intake was lowest (P<0.05) in Period 3. In terms of fatty acid content, there were significant interactions (P<0.05) for vaccenic acid (C18:1t11) and linoleic acid (C18:2c9c12) with the highest values in Period 3. Linolenic acid (C18:3c9c12c15) was higher in milk when cows grazed KY and significantly higher (P<0.05) in Period 3. It is concluded that kikuyu pastures complemented with maize silage and concentrates in winter-spring perform as tall fescue pastures in the season of herbage scarcity. Milk from cows grazing kikuyu grass pastures complemented with maize silage and concentrates has a higher content of linolenic fatty acid and an atherogenic index favorable for human health.

Effects of full-time v. part-time grazing on seasonal changes in milk coagulation properties and fatty acid composition

For this research communication our objective was to investigate to what extent milk coagulation properties and milk fatty acid (FA) composition were affected by different feeding systems, season and their interaction. Eighteen cows in total were subjected to one of three different feeding system treatments: full-time grazing or part-time grazing combined with indoor feeding of fresh grass with low or high concentrate supplementation. Milk was sampled in spring, summer and autumn. Milk coagulation time was 15.0, 19.0 and 17.7 min, coagulation dynamics 1.67, 3.41 and 1.79 min, and curd firmness 52.7, 32.4 and 47.0 mm in spring, summer and autumn, respectively. Thus, milk coagulation properties of the milk were lower during summer. There were strong seasonal effects on milk FA proportions, but there were not always changes with progressing season, or changes were different with respect to the impact of the feeding systems (system × season interaction). The milk fat was favourably rich in oleic acid, conjugated linoleic acid and α-linolenic acid and had a low n-6/n-3 fatty acid ratio in all systems. Factors like seasonal variations in grass composition and the energy balance of the cows were considered relevant for the milk FA composition. Overall, seasonal variations in milk quality were less pronounced with part-time grazing with fresh grass indoors as compared to full-time grazing without concentrate.

The Impact of Seasonality in Pasture-Based Production Systems on Milk Composition and Functionality

Seasonal calving, pasture-based dairy systems are widely practiced in countries with a temperate climate and plentiful rainfall such as Ireland and New Zealand. This approach maximizes milk production from pasture and, consequently, is a low-cost, low-input dairy production system. On the other hand, the majority of global milk supply is derived from high input indoor total mixed ration systems where seasonal calving is not practiced due to the dependence on ensiled silages, grains and concentrated feeds, which are available year-round. Synchronous changes in the macro and micronutrients in milk are much more noticeable as lactation progresses through early, mid and late stages in seasonal systems compared to non-seasonal systems-which can have implications on the processability and functionality of milk.

Challenges and Tendencies of Automatic Milking Systems (AMS): A 20-Years Systematic Review of Literature and Patents

Over the last two decades, the dairy industry has adopted the use of Automatic Milking Systems (AMS). AMS have the potential to increase the effectiveness of the milking process and sustain animal welfare. This study assessed the state of the art of research activities on AMS through a systematic review of scientific and industrial research. The papers and patents of the last 20 years (2000-2019) were analysed to assess the research tendencies. The words appearing in title, abstract and keywords of a total of 802 documents were processed with the text mining tool. Four clusters were identified (Components, Technology, Process and Animal). For each cluster, the words frequency analysis enabled us to identify the research tendencies and gaps. The results showed that focuses of the scientific and industrial research areas complementary, with scientific papers mainly dealing with topics related to animal and process, and patents giving priority to technology and components. Both scientific and industrial research converged on some crucial objectives, such as animal welfare, process sustainability and technological development. Despite the increasing interest in animal welfare, this review highlighted that further progress is needed to meet the consumers' demand. Moreover, milk yield is still regarded as more valuable compared to milk quality. Therefore, additional effort is necessary on the latter. At the process level, some gaps have been found related to cleaning operations, necessary to improve milk quality and animal health. The use of farm data and their incorporation on herd decision support systems (DSS) appeared optimal. The results presented in this review may be used as an overall assessment useful to address future research.

Changes in Physicochemical and Microbiological Properties, Fatty Acid and Volatile Compound Profiles of Apuseni Cheese during Ripening

The evolution during ripening on the quality of Apuseni cheese was studied in this research. The cheese samples were controlled and evaluated periodically (at 4 months) during 16 months of storage (at 2–8 °C) for physicochemical parameters (pH, moisture, fat, fat in dry matter, total protein, ash, NaCl), microbiological (total combined yeasts and molds count (TYMC), total viable count (TVC), Escherichia coli, Staphylococcusaureus, Salmonella, lactic acid bacteria (LAB)), fatty acids (FA) and volatile compounds. For better control of the quality of the cheese, the storage space was evaluated for TYMC and TVC. The ripening period showed improved effects on the quality of the cheese, showing lower values for moisture and pH and an increase in macronutrients. Both the cheese samples and the storage space were kept within the allowed microbiological limits. Lipids are predominant, the predominant FAs being saturated fatty acids (SFAs), which decrease, while monounsaturated fatty acids (MUFAs) increase. During ripening, the microbiological and chemical changes result in the development of flavor. Major volatile compounds such as 2-heptanone show accumulations, while acetophenone, limonene, or thymol show a decrease. In conclusion, Apuseni ripening cheese clearly involves a complex series of transformations, leading to a ripening cheese with improved nutritional and aromatic characteristics.

Development of Machine Learning Models to Predict Compressed Sward Height in Walloon Pastures Based on Sentinel-1, Sentinel-2 and Meteorological Data Using Multiple Data Transformations

Accurate information about the available standing biomass on pastures is critical for the adequate management of grazing and its promotion to farmers. In this paper, machine learning models are developed to predict available biomass expressed as compressed sward height (CSH) from readily accessible meteorological, optical (Sentinel-2) and radar satellite data (Sentinel-1). This study assumed that combining heterogeneous data sources, data transformations and machine learning methods would improve the robustness and the accuracy of the developed models. A total of 72,795 records of CSH with a spatial positioning, collected in 2018 and 2019, were used and aggregated according to a pixel-like pattern. The resulting dataset was split into a training one with 11,625 pixellated records and an independent validation one with 4952 pixellated records. The models were trained with a 19-fold cross-validation. A wide range of performances was observed (with mean root mean square error (RMSE) of cross-validation ranging from 22.84 mm of CSH to infinite-like values), and the four best-performing models were a cubist, a glmnet, a neural network and a random forest. These models had an RMSE of independent validation lower than 20 mm of CSH at the pixel-level. To simulate the behavior of the model in a decision support system, performances at the paddock level were also studied. These were computed according to two scenarios: either the predictions were made at a sub-parcel level and then aggregated, or the data were aggregated at the parcel level and the predictions were made for these aggregated data. The results obtained in this study were more accurate than those found in the literature concerning pasture budgeting and grassland biomass evaluation. The training of the 124 models resulting from the described framework was part of the realization of a decision support system to help farmers in their daily decision making.

Determination of changes in the microbial and chemical composition of Țaga cheese during maturation

Țaga cheese is a traditional Romanian smear-ripened cheese made from bovine milk and identified with the name of the village and caves where it is produced. As no previously reported microbiological and chemical studies have been undertaken on this product, this research aimed to investigate the microbiological and biochemical characteristics which ensure the uniqueness of Țaga cheese during the ripening process, to inform producers as to key quality determinants. Cheese samples, consisting of retail blocks, were collected on days 2, 5, 12, 18, and 25 of the ripening process. The evolution of lactic microbiota during the production and maturation of traditional cheeses involves isolating lactic acid microorganisms present in cheese. Cheese samples were analyzed for pH, fat, NaCl, fatty acids, and volatile compounds. The microbial ecosystem naturally changes during the maturation process, leading to variation in the microorganisms involved during ripening. Our results show that specific bacteria were identified in high levels during the entire ripening process and may be responsible for milk fat lipolysis contributing directly to cheese flavor by imparting detailed fatty acid flavor notes, or indirectly as precursors formation of other flavor compounds.