Diet Of Cows Research Articles

Liver Transcriptomic Profiles of Ruminant Species Fed Spent Hemp Biomass Containing Cannabinoids.

The inclusion of spent hemp biomass (SHB), an extracted byproduct from industrial cannabidiol (CBD) production, in the diets of dairy cows and lambs appears to be safe with minor effects on the metabolism, including a decrease in circulating cholesterol and increase bilirubinemia, both associated with liver metabolism. Those effects could be consequence of the presence of cannabinoids, particularly Δ9-tetrahydrocannabinol (THC) and CBD in the SHB. This study aimed to study the transcriptional profile of the liver of dairy cows and lambs fed SHB. Dairy cows received SHB or alfalfa pellet for four weeks of intervention (IP) and four weeks of withdrawal periods (WP). Finishing lambs were fed a control diet (CON), 10% (LH2), or 20% (HH2) SHB for 2 months or 1 month followed by 1-month SHB withdrawal (LH1 and HH1, respectively). RNA sequencing was performed, and the mRNA was annotated using the latest reference genomes. The RNAseq data were filtered, normalized for library size and composition, and statistically analyzed by DESeq2. The bioinformatic analysis was performed by using DAVID, Gene Set Enrichment Analysis (GSEA), and the Dynamic Impact Approach. Using a 0.2 FDR cut-off, we identified only ≤24 differentially expressed genes (DEG) in the liver by feeding SHB in dairy cows and a larger number of DEGs in lambs (from 71 in HH1 vs. CON to 552 in LH1 vs. CON). The KEGG analysis demonstrated that feeding SHB in dairy cows and lambs had relatively minor to moderate metabolic alterations in dairy cows and lambs mainly associated with amino acids and lipid metabolism whereas cholesterol synthesis was overall activated in lambs. GSEA identified activation of the PPAR signaling pathway only in dairy cows. We found an opposite effect on activation of metabolism of drug and xenobiotics by cytochrome P450 enzymes in dairy cows and lambs receiving less SHB but an inhibition in HH2 lambs. Immune system-related pathways were inhibited by feeding SHB in lambs, but the impact was minor. Cumulatively, inclusion of SHB containing cannabinoids in dairy and lambs demonstrate very little effects on the alteration of transcriptomic profile of the liver.

Urea in the Diets of Dairy Cows

In most farms of the Nakhchivan Autonomous Republic, the basis of the feed balance of cattle consists of roughage, straw, hay, relatively less succulent feed and a very small part - fresh grass and fortified feed. That is why animals on these farms in winter stall conditions consume less digestible protein by an average of 40-55 g or more per unit of feed. On farms, urea was used to provide sufficient protein for cattle. During the experiment, cows of both groups (experimental and control) were fed in stall conditions and received the same number of feed shares according to their nutritional value. The only difference was that each cow in the experimental group was given an additional 80 g of urea per day. The results of our experience show that the daily milk yield of each cow that received 80 g of urea in the feed ration is on average 1,15 kg or 29,9% more compared to cows that did not receive urea, and the fat content of milk is from 0.1 up to 0,39%. The live weight of each cow receiving urea (over 123 days of experiment) was on average 17,47 kg greater than that of cows not receiving urea. The use of urea in livestock farming not only increases milk and meat productivity, but also reduces the cost of production.

Influence of dietary mulberry (Morus alba L.) leaf supplementation on production performance, blood metabolites, rumen fermentation characteristics and ruminal bacteria community in lactating dairy cows

The purpose of this study was to determine the effect of mulberry (Morus alba L.) leaf (ML) supplementation on the productivity, blood metabolism, rumen fermentation characteristics and rumen microbial population in lactating dairy cows. Twelve healthy multiparous Holstein dairy cows (initial characteristics: body weight = 442.83 ± 86.87 kg; milk yield = 12.55 ± 1.91 kg/d; days in milk = 150.0 ± 47.0 d) were randomly allocated to two treatment groups of six cows each. The cows were fed two different diets: a control diet (basal diet without ML; CTRL group) and a ML-supplemented diet (basal diet + 300 g ML; ML group). The trial lasted for a total of 28 d after an adjustment period of 14 d. The total rumen volatile fatty acid (VFA) levels (p = .063) and the propionate level (p < .05) were increased in the ML group, whereas the ratio of acetate to propionate was significantly decreased (p < .05). A microbiome study demonstrated that the dietary treatments significantly influenced the composition of rumen bacteria. The ruminal populations of Paludibacter propionicigenes, Ruminococcus sp. JE7A12 and Prevotella oris were greater (p < .05) in ML group than in CTRL group, while Enterococcus faecalis numbers significantly decreased (p < .05) in the ML group. Supplementing a dairy cow diet with 300 g ML has the potential to alter the microbial community and fermentation in the rumen, leading to an increase in propionate synthesis.

Rumen metagenome reveals the mechanism of mitigation methane emissions by unsaturated fatty acid while maintaining the performance of dairy cows

Dietary fat content can reduce the methane production of dairy cows; however, the relevance fatty acid (FA) composition has towards this inhibitory effect is debatable. Furthermore, in-depth studies elucidating the effects of unsaturated fatty acids (UFA) on rumen function and the mechanism of reducing methane (CH4) production are lacking. This study exposed 10 Holstein cows with the same parity, similar milk yield to two total mixed rations: low unsaturated FA (LUFA) and high unsaturated FA (HUFA) with similar fat content. The LUFA group mainly added fat powder (C16:0 > 90%), and the HUFA group mainly replaced fat powder with extruded flaxseed. The experiment lasted 26 d, the last 5 d of which, gas exchange in respiratory chambers was conducted to measure gas emissions. We found that an increase in the UFA in diet did not affect milk production (P > 0.05) and could align the profile of milk FAs more closely with modern human nutritional requirements. Furthermore, we found that increasing the UFA content in the diet lead to a decrease in the abundance of Methanobrevibacter in the rumen (|linear discriminant analysis [LDA] score| > 2 and P < 0.05), which resulted in a decrease in the relative abundance of multiple enzymes (EC:1.2.7.12, EC:2.3.1.101, EC:3.5.4.27, EC:1.5.98.1, EC:1.5.98.2, EC:6.2.1.1, EC:2.1.1.86 and EC:2.8.4.1) during methanogenesis (P < 0.05). Compared with the LUFA group, the pathway of CH4 metabolism was inhibited in the HUFA group (|LDA| > 2 and P < 0.05), which ultimately decreased CH4 production (P < 0.05). Our results illustrated the mechanism involving decreased CH4 production when fed a UFA diet in dairy cows. We believe that our study provides new evidence to explore CH4 emission reduction measures for dairy cows.

Grape seed oil in the diet of primiparous Jersey cows before and after parturition: effects on performance, health, rumen environment, and milk quality.

The objective of the study was to determine whether adding grape seed oil (GSO) to the diet of primiparous Jersey breeds during the transition period would improve animal health by measuring effects on the rumen environment, serum biochemistry, oxidative response, and the composition and quality of milk. We used 14 Jersey heifers, weighing an average of 430kg and 240days of gestation. The animals were divided into two groups and offered a basal diet, including GSO in the concentrate for the GSO group (dose of 25mL per animal day) and the same dose of soybean oil (SO) for the control group. The animals were allocated and maintained in a compost barn system, receiving an anionic diet (pre-partum) and a diet for postpartum lactating animals. Dry matter intake (DMI), milk production, serum biochemistry, serum and milk oxidative stability, ruminal fluid and milk fatty acid profile, milk qualitative aspects, and ruminal parameters such as pH, bacterial activity, and protozoan count were evaluated. The addition of GSO had a positive effect on the health of the cows, especially on the oxidative stability of the cows, by increasing total thiols (P = 0.03), higher plasma ferric reducing capacity (FRAP) (P = 0.01), and total antioxidant capacity (TAC) (P = 0.01). In the oxidative stability of the milk produced by the treated animals, there was also an increase in TAC (P = 0.05) and FRAP (P = 0.03). Discreet changes were observed in the ruminal environment with a decreasing trend in pH (P = 0.04) but an increase in bacterial activity (P = 0.05) and protozoa counts (P = 0.07) in cows that consumed the additive. GSO consumption affected the fatty acid profile in milk, increasing saturated fatty acids (SFA) (P = 0.05) and reducing unsaturated fatty acids (UFA) (P = 0.03). The oil did not affect milk production or efficiency in the postpartum period. Based on this information, it is concluded that the addition of GSO positively affects the cow's antioxidant system.

Feeding nanoparticles of copper oxide coated with lysine with or without added antagonists affects the copper status but not performance of Holstein dairy cows

The apparent absorption of copper (Cu) in ruminants is low, with between 0.01 and 0.07 g/g absorbed from sources such as copper oxide (CuO) under typical feeding conditions, resulting in high levels of excretion. Improving the bioavailability of Cu could reduce the supplemental amount required to maintain Cu status and reduce excretion, particularly in the presence of dietary antagonists such as sulfur (S) and molybdenum (Mo). The objective of our study was to determine the Cu status of cows when fed nanoparticle CuO coated with Lys compared with conventional CuO when fed without or in combination with antagonists to Cu absorption (S and Mo) in the diet of dairy cows. Fifty-six multiparous Holstein-Friesian cows that were 48 d ± 17.4 (mean ± SD) post calving and yielding 40.6 ± 6.9 kg milk/d were used in a 2 × 2 factorial design. The 4 treatment groups were; CuO (O-), CuO with added antagonists (O+), nano CuO with a lysine coating (N-), and nano CuO with a Lys coating with added antagonists (N+), fed for 16 wks. We formulated the diets to contain approximately 17 mg Cu/kg dry matter (DM) and diets with antagonists contained an additional 1 g S/kg DM and 6 mg Mo/kg DM, with Lys added to O- and O+ to provide the same daily supply as N- and N+. Blood samples were collected at wk 0, 2, 4, 6, 10 and 16, and liver biopsy samples at wk 0 and 16. We found no effect of dietary treatment on DM intake, milk yield, live weight or body condition score, with mean values of 23.3 kg/d, 40.1 kg/d, 646 kg and 2.68, but milk SCC was higher in cows fed conventional compared with non CuO, or with added antagonist. We also found no effect of treatment on blood activity of gamma glutamyl transferase, superoxide dismutase or ceruloplasmin, hematology profile, or plasma Cu and iron concentration. We found that plasma Mo concentration was increased from 0.36 µmol/L in cows fed O- or N- to 0.80 µmol/L in those receiving O+ or N+. Additional dietary antagonists also decreased the concentration of Cu in the liver of cows fed conventional CuO (C+) over the study period by 1.3 mg/kg DM/d, but in cows fed dietary antagonists and nano CuO coated with Lys (N+), liver Cu concentration was increased by 1.1 mg/kg DM/d. Our study is the first to demonstrate that reducing the particle size of CuO into the nano scale with a lysine coating improves the bioavailability of CuO in the presence of dietary antagonists in dairy cattle, and we did not observe any negative effects on performance or health.

Multispecies pasture diet and cow breed impacts on milk composition and quality in a seasonal spring-calving dairy production system

In recent years, there has been significant emphasis on the composition of pasture-based cow feed and the potential benefits of incorporating multispecies swards to improve sustainability and biodiversity. This study compared the effects of a conventional perennial ryegrass (PRG) monoculture supported by high chemical nitrogen (N) usage with a low chemical N application multispecies sward system (MSS) on the composition and quality of milk across lactation using spring-calving Holstein-Friesian (HF) and Jersey Holstein-Friesian (JFX) cows. Bulk milk samples (n = 144) were collected from each group at morning and evening milking on a weekly basis (n = 36) throughout lactation and analyzed for gross composition and physico-chemical properties. Cow breed had a significant impact on milk profile, with milk from HF cows having significantly smaller milk fat globule (MFG) size, higher instability index values, higher yield, and lower total solids levels, compared with JFX cows. Notably, HF cows had increased milk total solids and fat levels when fed on MSS, as opposed to the PRG-fed HF cows. Feeding MSS pasture increased creaming velocity values in mid and late lactation, and resulted in similar milk gross composition to PRG. In comparison to PRG, MSS-fed groups showed significantly increased total solids yield, including higher levels of protein and fat yield. In late lactation, MSS feeding was associated with reduced MFG size. All physicochemical properties studied (MFG size, creaming velocity, instability index) showed decreasing values from early to late lactation stage. Overall, these findings demonstrate the significant effects of cow diet, breed and stage of lactation on compositional and physico-chemical characteristics of milk, with important implications for milk processing and dairy product quality.

Lactational performance, ruminal fermentation, and enteric gas emission of dairy cows fed an amylase-enabled corn silage in diets with different starch concentrations

This study investigated the effects of feeding an amylase-enabled corn silage (ACS) on the performance and enteric gas emissions in lactating dairy cows. Following a 2-wk covariate period, 48 mid-lactation Holstein cows were assigned to 1 of 3 treatments in a 10-wk randomized complete block design experiment. Treatments were diets containing the same proportion of corn silage (40% of dietary DM) as follows: (1) a conventional hybrid corn silage control (CON), (2) ACS replacing the control silage (ADR), and (3) the ADR diet replacing soybean hulls with ground corn grain to achieve the same dietary starch concentration as CON (ASR). Control corn silage and ACS were harvested on the same day and contained 40.3% and 37.1% DM and (% of DM): 37.2% and 41.0% NDF and 37.1% and 30.0% starch, respectively. Enteric gas emissions were measured using the GreenFeed system. Two cows were culled due to health-related issues during the covariate period. Ruminal fluid was collected from 24 cows (8 per treatment) using the orogastric ruminal sampling technique. When compared with CON, cows fed ADR had increased DMI during experimental wk 3, 4, and 9, but treatment did not affect milk or ECM milk yields (39.0 kg/d on average; SEM = 0.89). Compared with CON, feed efficiency (per unit of milk, but not ECM) tended to be lower for ADR, whereas milk true protein concentration (a tendency) and yield were lower for ASR. Milk urea N was decreased by both ADR and ASR diets relative to CON. Compared with CON, daily CH4 emission and emission intensity were increased by ADR but not ASR. Total protozoal count tended to be increased by both diets formulated with ACS when compared with control corn silage. Total-tract digestibility of dietary NDF was greater for ASR, and that of ADF was greater for both ADR and ASR versus CON. The molar proportion of acetate (a tendency) and acetate-to-propionate ratio were increased by ADR, but not ASR, when compared with CON. Replacement of CON with ACS (having lower starch concentration) in the diet of dairy cows increased DMI during the initial weeks of the experiment, maintained ECM, tended to decrease feed efficiency, and increased enteric CH4 emissions, likely due to increased intake of digestible fiber, compared with CON.

Optimization of Sodium-Potassium Ratio in Cow Diets

In the conditions of the Nakhchivan Autonomous Republic, research has been carried out on the prevention of metabolic disorders and optimization of the sodium-potassium ratio in the feed ration of cows. The diets were identical in composition and nutritional value, but the ratio of sodium and potassium in the groups was different due to different amounts of table salt. During the stall period of the experiment, the ratio of sodium and potassium in group I was 0.36, in group II — 0.43, and in group III — 0.48. It should be noted that this attitude in groups II and III contributed to a greater consumption of roughage and succulent feed than in the control group. During the grazing period, cows of all groups also received the same rations. However, the ratio of sodium and potassium in them was different. Thus, in group II it was 0.32, in group III — 0.41 versus 0.24 in the control. In group I for 1 feed units sodium accounted for 5.7 g, in II — 7.6 and III — 10.0 g. Cows of groups II and III consumed more grass on pasture by 4.8 and 9.6%, and green fertilizer by 3.2 and 7.6% compared to control. The amount of grass eaten on pasture was determined using the reverse calculation method. On average, per lactation in groups II and III there was 1.4 and 3.0 g more sodium per feed unit, respectively, than in group I. The nutritional value of the diets corresponded to the needs and level of productivity of the animals. Thus, optimizing the sodium-potassium ratio in the diets of highly productive cows by increasing the rate of sodium chloride by 40% in the stall and by 100% in the grazing periods with excess potassium in the diets ensures improved mineral metabolism, increases the use of nutrients and increases milk yield by 4%. Fat content by 8,8% on average per lactation.

Dietary supplementation of rumen native microbes improves lactation performance and feed efficiency in dairy cows

Objectives were to determine the effects of 2 dietary microbial additives supplemented to diets of Holstein cows on productive performance and feed efficiency. One-hundred and 17 Holstein cows were enrolled at 61 d (31 to 87 d) postpartum in a randomized complete block design experiment. Cows were blocked by parity group, as nulliparous or multiparous cows and, within parity, by pre-treatment energy-corrected milk yield. Within block, cows were randomly assigned to one of 3 treatments administered as top-dress for 140 d. Treatments consisted of either 100 g of corn meal containing no microbial additive (CON; 15 primiparous and 25 multiparous), 100 g of corn meal containing 5 g of a mixture of Clostridium beijerinckii and Pichia kudriavzevii (G1; 4 × 107 cfu of C. beijerinckii and 1 × 109 cfu of P. kudriavzevii; 14 primiparous and 24 multiparous), or 100 g of corn meal containing 5 g of a mixture of C. beijerinckii, P. kudriavzevii, Butyrivibrio fibrisolvens, and Ruminococcus bovis (G2; 4 × 107 cfu of C. beijerinckii, 1 × 109 cfu of P. kudriavzevii, 1 × 108 cfu of B. fibrisolvens, and 1 × 108 cfu of R. bovis; 15 primiparous and 24 multiparous). Intake of DM, milk yield, and BW were measured daily, whereas milk composition was analyzed at each milking 2 d a week, and body condition was scored twice weekly. Milk samples were collected on d 60 and 62 in the experiment and analyzed for individual fatty acids. The data were analyzed with mixed-effects models with orthogonal contrast to determine the impact of microbial additive (MA; CON vs. 1/2 G1 + 1/2 G2) and type of microbial additive (TMA; G1 vs. G2). Results are described in sequence as CON, G1, and G2. Intake of DM (22.2 vs. 22.4 vs. 22.4 kg/d), BW (685 vs. 685 vs. 685 kg) and the daily BW change (0.40 vs. 0.39 vs. 0.39 kg/d) did not differ among treatments; however, feeding MA tended to increase BCS (3.28 vs. 3.33 vs. 3.36). Supplementing MA increased yields of milk (39.9 vs. 41.3 vs. 41.5 kg/d), ECM (37.9 vs. 39.3 vs. 39.9 kg/d), fat (1.31 vs. 1.37 vs. 1.40 kg/d), total solids (4.59 vs. 4.75 vs. 4.79 kg/d), and ECM per kg of DMI (1.72 vs. 1.76 vs. 1.80 kg/kg). Furthermore, cows fed MA increased yields of pre-formed fatty acids in milk fat (>16C; 435 vs. 463 vs. 488 g/d), particularly unsaturated fatty acids (367 vs. 387 vs. 410 g/d), such as linoleic (C18:2 cis-9, cis-12; 30.9 vs. 33.5 vs. 35.4 g/d) and α-linolenic acids (C18:3 cis-9, cis-12, cis-15; 2.46 vs. 2.68 vs. 2.82 g/d) on d 60 and 62 in the experiment. Collectively, supplementing G1 and G2 improved productive performance of cows with no differences between the 2 MA.

Effects of Sweet and Forge Sorghum Silages Compared to Maize Silage without Additional Grain Supplement on Lactation Performance and Digestibility of Lactating Dairy Cows.

This study investigated the effects of replacing maize silage (MZS) with high-sugar sorghum silage (HSS) or forage sorghum silage (FSS) without additional grain supplement in the diets of dairy cows on nutrient digestibility, milk composition, nitrogen (N) use, and rumen fermentation. Twenty-four Chinese Holstein cows (545 ± 42.8 kg; 21.41 ± 0.62 kg milk yield; 150 ± 5.6 days in milk) were randomly assigned to three dietary treatments (n = 8 cows/treatment). The cows were fed ad libitum total mixed rations containing (dry matter basis) either 40% MZS (MZS-based diet), 40% HSS (HSS-based diet), or 40% FSS (FSS-based diet). The study lasted for 42 days, with 14 days devoted to adaptation, 21 days to daily feed intake and milk production, and 7 days to the sampling of feed, refusals, feces, urine, and rumen fluid. Milk production was measured twice daily, and digestibility was estimated using the method of acid-insoluble ash. The data were analyzed using a one-way ANOVA in SPSS 22.0 according to a completely randomized design. Dietary treatments were used as fixed effects and cows as random effects. The results indicate that MZS and HSS had greater crude protein but less neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), and a lower pH than FSS (p ≤ 0.04). High starch contents in MZS and water-soluble carbohydrate (WSC) contents in HSS were observed (p < 0.01). While the highest starch intake was observed for the MZS-based diet, the highest WSC intake was noted for the HSS-based diet, and the highest NDF, ADF, ADL intake was observed for the FSS-based diet (p ≤ 0.05). The diets, including MZS and HSS, had greater digestibility than that of FSS (p ≤ 0.03). Feeding MZS- and HSS-based diets increased the yield, fat, and protein content of the milk, as well as feed conversion efficiency (p ≤ 0.03). However, feeding the MZS- and HSS-based diets decreased the contents of milk urea N, urinary urea N, and urinary N excretion more than the FSS-based diet (p ≤ 0.05). The N use efficiency tended to increase relative to diets containing MZS and HSS compared with FSS (p = 0.06 and p = 0.09). Ruminal ammonia-N and pH were lower, but total volatile fatty acids, acetate, and propionate were higher in cows fed the HSS- and MZS-based diets compared to those fed the FSS-based diet (p ≤ 0.03). It appears as though replacing MZS with HSS in the diet of cows without additional grain supplements has no negative influence on feed intake, milk yield, N utilization, or ruminal fermentation.

Energy and protein levels in dairy cow diets to recover milk ethanol stability

The objective of this study was to evaluate the effect of energy and protein in the diet on the recovery of milk ethanol stability (MES) induced by feed restriction. Twelve Holstein and Holstein x Jersey crossbred cows with an average of 146 ± 50 d in milk, 575.4 ± 70 kg of body weight, and 18.93 ± 5.46 kg/d of milk yield were distributed in a 3x3 Latin square design with 3 treatments and 3 experimental periods. Each experimental period lasted 24 d, comprising 3 phases: a 13-d adaptation phase (100E+100P), a 4-d induction phase for milk ethanol instability (50E+50P), and a 7-d recovery phase for MES (3 treatments). The 3 treatments during the recovery phase consisted of 3 diets aiming to meet the requirements of energy and protein (100E+100P), only energy (100E+50P), or only protein (50E+100P). The diet during the adaptation and induction phases was common for all cows. The energy and protein levels to meet each cow's requirements were based on the group average. Restriction of energy and protein reduced dry matter, crude protein, and total digestive nutrient intake for cows fed 100E+50P and 50E+100P. The lowest body weight was observed for cows fed 50E+100P, with no difference for body condition score. During the induction phase, MES "was" reduced by 9 percentage units. Cows fed 100E+100P recovered MES in the first days of the recovery phase, while 100E+50P slightly improved MES, and 50E+100P had a constant decrease in MES. Cows fed 100E+50P and 50E+100P produced, respectively, 3.6 and 5.9 kg less milk than those fed 100E+100P. The 50E+100P treatment exhibited the highest milk fat content and somatic cell score, along with the lowest milk lactose content. Protein content was higher in the 100E+100P treatment. Cows fed 50E+100P showed higher serum albumin levels compared with those on the 100E+100P treatment, not differing from the 100E+50P treatment. We concluded that the complete recovery of MES in cows with feed restrictions is possible only by supplying both the energy and protein requirements in the cows' diet. However, restricting energy intake poses a greater limitation on MES recovery compared with restricting protein.

Assessing the effects of live yeast supplementation to diets containing high starch of dairy cows on rumen fermentation and methane production in vitro

Abstract This study was conducted to evaluate the effects of live Saccharomyces cerevisiae yeast (LY) supplementation on high-starch diets for dairy cows. Using a 2 × 2 factorial design, four treatment groups were examined: adequate starch without LY (AS-control), AS with LY (AS-LY), high starch without LY (HS-control), and HS with LY (HS-LY). LY was added at 2.9 × 106 CFU/200 mg DM or without yeast. In vitro gas and methane (CH4) production, organic matter (OM) digestibility, rumen fermentation, and metabolizable energy (ME) were analyzed. The Hohenheim Gas Test apparatus was used, and total gas volumes were measured at various incubation hours. Results showed no significant effects of LY or dietary starch ratio on gas kinetics, total gas, or CH4 production. Similarly, OM digestibility, fermentation kinetics, and ME were unaffected. In conclusion, LY supplementation did not alter in vitro gas, CH4 production, OM digestibility, rumen fermentation, or ME. Further research could investigate the underlying mechanisms, such as rumen microbial population influences.

Alpine grazing management, breed, and diet effects on coagulation properties, composition, and microbiota of dairy cow milk by commercial mountain-based herds

Cow milk microbiota has received increased attention in recent years, not only because of its importance for human health but also because of its effect on the quality and technological properties of milk. Several studies, therefore, have investigated the effect of various production factors on the microbial composition of milk. However, most of the previous studies considered a limited number of animals from experimental or single farm, which could have biased the results. Therefore, this study aimed to understand the effect of different alpine production systems on the compositional and microbiological quality of milk, considering commercial herds with different feeding intensities and cattle breeds. The results obtained in this work indicated that the month/season of sampling (July for summer or February for winter) more than farm, breed and cow diet exerted significant effects on cow milk parameters and microbiota. In particular, significant differences were observed for urea content in milk between sampling seasons. Differences in milk fat were mainly related to breed specific effects. From a microbiological point of view, statistically significant differences were found in presumptive lactic acid bacteria counts. Based on a culture-independent method, milk obtained in February harbored the highest number of Firmicutes (e.g., Lactobacillus) and the lowest number of Actinobacteria (e.g., Corynebacterium). Moreover, bacterial richness and diversity were higher in July/summer during alpine pasture season indicating a significant effect of pasture feed on the growth of bacterial communities. The results of this study highlighted the effect of month/season mainly related to differences in feeding management (e.g., access to pasture during vegetation period, concentrates supplementation) on composition and microbiota in milk.

Zinc Supplementation Improves Texture, Oxidative Stability of Caciotta Cheese and Reduces Biogenic Amines Production.

Zinc is essential for animals, playing a vital role in enzyme systems and various biochemical reactions. It is crucial to ensure a sufficient intake of zinc through the diet to maintain efficient homeostasis. Only few studies on zinc effect in cow lactating diet evaluated the effects on milk and cheese quality, with conflicting findings. 24 cows of the Friesian breed were divided into two groups (CTR: control and TRT: treated group). Cows were selected for age, body weight, parity and phase of lactations (mid lactation, 140-160 days). CTR diet contained 38 mg/kg of Zn and TRT diet was supplied with 120 mg/kg of complete feed for 60 days. The objective of current investigation was to evaluate the impact of a dietary Zinc Oxide (ZnO) integration of lactating Friesian cows on chemical composition, zinc content, fatty acid and proteic profile, ammine content, pH, aw, texture, and sensory profile of cheese and to improve the chemical-nutritional quality of milk and cheese. The results showed that ZnO supplementation reduced mesophilic aerobic bacteria and Presumptive Pseudomonas spp. growth, proteolysis, biogenic amines content, lipid oxidation, odour intensity and sour and increased hardness, gumminess, chewiness, elasticity of cheese. Biogenic amines are considered an important aspect of food safety. ZnO integration in cow diet could represent a promising strategy for improving the quality, the safety and shelf-life of caciotta cheese.

Evaluation of a novel palm-free fat supplement to reduce the carbon footprint of diets for dairy cows

Most fat supplements added to dairy diets are derived from palm acid oil or palm fatty acid distillate. There are environmental concerns about palm oil production due to deforestation and high greenhouse gas (GHG) emissions. The objective of this study was to evaluate a palm-free fat supplement, Envirolac. Envirolac contains vegetable oils, marine oils and glycerine encapsulated within a cellulosic fibre-clay mineral carrier matrix. The carrier matrix has small particle size to facilitate rapid rumen passage and minimal interference with rumen digestion. Fifty cows were divided into two balanced groups of 25 cows. Each group received Control (calcium soap of palm fatty acid distilate, 0.5 kg/d) and Envirolac (0.5 kg/d) diets in a crossover design with two feeding periods of four weeks duration, so that each cow received both diets. Envirolac has a lower total fat concentration than the calcium soap, so the feeding rate delivered less total fat. When fed on Envirolac, cows yielded more milk 40.7 v 40.1 kg/d), energy-corrected milk (ECM; 42.9 v 41.3 kg/d) and milk components (1605 v 1514 g fat, 1239 v 1199 g protein, 1871 v 1839 g lactose, per day), and produced milk with higher concentrations of fat (40.1 v 38.6 g/kg) and protein (30.7 v 30.1 g/kg), than when fed on Control. When fed on Envirolac, cows produced milk with higher concentrations of fatty acids (FA) synthesised de novo in the mammary gland (25.5 v 23.6 g/100 g total FA), lower concentration of palmitic acid (35.5 v 37.2 g/100 g total FA), and higher concentrations of some long-chain fatty acids (C20:0, C20:1, C20:3n3, C21:0, C22:0, C22:6n3 and C23:0), than when fed on Control. There was no effect of treatment on dry matter intake (DMI; mean 23.4 kg/d), so feed efficiency was higher (1.83 v 1.76 kg ECM/kg DMI) for Envirolac than Control. There was no effect of treatment on dry matter digestibility (0.73), methane production (433 g/d), methane yield (19.3 g/kg DMI) or methane intensity (10.9 g/kg ECM). Feed carbon footprint of Envirolac was calculated to be 1028 g CO2eq/kg DM, which is 0.46 of the value for a calcium soap (2830 g CO2eq/kg DM), and reduced feed carbon footprint per kg ECM milk production by 11 %. This study demonstrates that Envirolac can replace palm-based fat supplements in dairy diets to improve feed efficiency and reduce the carbon footprint of milk production.

Farm-level risk factors associated with increased milk β-hydroxybutyrate and hyperketolactia prevalence on farms with automated milking systems

The objectives of this study were to determine the farm-level hyperketolactia (HKL) prevalence, as diagnosed from milk β-hydroxybutyrate (BHB) concentration, on dairy farms milking with an automatic milking system (AMS) and to describe the farm-level housing, management, and nutritional risk factors associated with increased farm-average milk BHB and the within-herd HKL prevalence in the first 45 DIM. Canadian AMS farms (n = 162; eastern Canada n = 8, Quebec n = 23, Ontario n = 75, western Canada n = 55) were visited once between April to September 2019 to record housing and herd management practices. The first test milk data for each cow under 45 DIM were collected, along with the final test of the previous lactations for all multiparous cows, from April 1, 2019 to September 30, 2020. The first test milk BHB was then used to classify each individual cow as having HKL (milk BHB ≥ 0.15 mmol/L) at the time of testing. Milk fat and protein content, milk BHB, and HKL prevalence were summarized by farm and lactation group (all, primiparous, and multiparous). During this same time period, formulated diets for dry and lactating cows, including ingredients and nutrient composition, and AMS milking data were collected. Data from the AMS were used to determine milking behaviors and milk production of each herd during the first 45 DIM. Multivariable regression models were used to associate herd-level housing, feeding management practices, and formulated nutrient composition with first test milk BHB concentrations and within-herd HKL levels separately for primiparous and multiparous cows. The within-herd HKL prevalence for all cows was 21.8%, with primiparous cows having a lower mean prevalence (12.2 ± 9.2%) than multiparous cows (26.6 ± 11.3%). Milk BHB concentration (0.095 ± 0.018 mmol/L) and HKL prevalence for primiparous cows were positively associated with formulated prepartum DMI and forage content of the dry cow diet while being negatively associated with formulated postpartum DMI, the major ingredient in the concentrate supplemented through the AMS, and the PMR-to-AMS concentrate ratio. However, multiparous cows' milk BHB concentration (0.12 ± 0.023 mmol/L) and HKL prevalence were positively associated with the length of the previous lactation, milk BHB at dry off, prepartum diet nonfiber carbohydrate content, and the major forage fed on farm, while tending to be negatively associated with feed bunk space during lactation. This is the first study to determine the farm-level risk factors associated with herd-level prevalence of HKL in AMS dairy herds, thus helping optimize management and guide diet formulation to promote the reduction of HKL prevalence.

Asparagopsis taxiformis inclusion in grass silage-based diets fed to Norwegian red dairy cows: Effects on ruminal fermentation, milk yield, and enteric methane emission

Efforts to mitigate enteric methane (CH4) emission from ruminants by using the red macroalgae Asparagopsis taxiformis (AT) have demonstrated promising results both in vitro and in vivo. We assessed the effects of wild harvested and freeze-dried AT inclusion in the grass silage-based diets of Norwegian Red dairy cows on feed intake, milk yield and composition, rumen fermentation and CH4 emission. Fifteen (9 rumen cannulated and 6 intact) multiparous cows with an average (±SD) covariate period milk yield (MY) of 33.0 (3.8) kg/day were used in the experiment. The cows were divided into three groups (n = 5) after blocking for cannulation, and initial MY. After feeding on a common diet for 21 days (i.e., Covariate period), the groups were randomly allocated to three treatments: Control (no seaweed), 0.125%AT (Control + 0.125%AT, on organic matter (OM) basis) and 0.25%AT (Control + 0.25%AT, on OM basis). The cows were adapted to their diets for 13 days, followed by 39 experimental days for data collection. Inclusion of AT at 0.125% level did not affect dry matter intake (DMI, kg/d) but signicantly reduced both MY and energy corrected milk yield (ECM, kg/d) (P < 0.05) with a tendency for lower CH4 production (g/d) relative to the control group. Dry matter intake, ECM and CH4 production were reduced (P < 0.05) by 0.25%AT inclusion relative to the Control group. Apparent total tract nutrient digestibility (%), ECM per kg DMI, CH4 yield (g CH4/kg DMI) and CH4 intensity (g CH4/kg ECM) were not affected by AT inclusion. Inclusion of AT, at both levels, significantly reduced (P < 0.05) ruminal fluid total short chain fatty acids and molar proportions of actate, while increasing (P < 0.05) the molar proportion of propionate and isovalerate. Inclusion of AT decreased contents (%) of milk fat (P = 0.018) and protein (P = 0.010) resulting in significanly lower fat and protein yields. Lactose content (%) was higher for the AT groups (P = 0.021) but this did not compensate for lower MY resulting in lower milk lactose yield. Milk iodine content increased in a dose dependent manner with AT inclusion. In conclusion, AT inclusion at 0.25% level reduced CH4 emission from dairy cows with a grass silage-based diets. However, the reduced DMI for the 0.25%AT group along with reduced MY and elevated milk iodine content for both AT groups, for this particular harvest of AT, would suggest possible constraints for large scale inclusion of AT in dairy cow production.

Effect of dietary protein source and Saccharina latissima on nutritional and safety characteristics of milk.

Wheat distillers' grains (WDG) and seaweeds are recommended as alternative protein sources and enteric methane mitigators in dairy cow diets, respectively, but little is known about their impact on milk quality and safety. In the present study, 16 cows in four 4 × 4 Latin squares were fed isonitrogenous diets (50:50 forage:concentrate ratio), with rapeseed meal (RSM)-based or WDG-based concentrate (230 and 205 g kg-1 dry matter) and supplemented with or without Saccharina latissima. Replacement of RSM with WDG enhanced milk nutritional profile by decreasing milk atherogenicity (P = 0.002) and thrombogenicity (P = 0.019) indices and the concentrations of the nutritionally undesirable saturated fatty acids - specifically, lauric (P = 0.045), myristic (P = 0.022) and palmitic (P = 0.007) acids. It also increased milk concentrations of the nutritionally beneficial vaccenic (P < 0.001), oleic (P = 0.030), linoleic (P < 0.001), rumenic (P < 0.001) and α-linolenic (P = 0.012) acids, and total monounsaturated (P = 0.044), polyunsaturated (P < 0.001) and n-6 (P < 0.001) fatty acids. Feeding Saccharina latissima at 35.7 g per cow per day did not affect the nutritionally relevant milk fatty acids or pose any risk on milk safety, as bromoform concentrations in milk were negligible and unaffected by the dietary treatments. However, it slightly reduced milk concentrations of pantothenate. Feeding WDG to dairy cows improved milk fatty acid profiles, by increasing the concentrations of nutritionally beneficial fatty acids and reducing the concentration of nutritionally undesirable saturated fatty acids, while feeding seaweed slightly reduced pantothenate concentrations. However, when considering the current average milk intakes in the population, the milk compositional differences between treatments in this study appear relatively small to have an effect on human health. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Эффективность препарата «МАСТИБЛОК® гель» при лечении мастита у коров в период лактации

The purpose of the research was to study the effectiveness of a new medicinal product for veterinary use «MASTIBLOCK gel» in the treatment of mastitis in cows during lactation. 5 groups (10 animals each) of lactating cattle with various forms of mastitis were formed: group 1 – subclinical mastitis; group 2 – acute serous mastitis; group 3 – chronic serous mastitis; group 4 – acute catarrhal mastitis; group 5 – chronic catarrhal mastitis. For the 1st, 2nd and 4th groups, therapy was carried out for 7 days, for the 3rd and 5th – for 14 days. The drug was used externally for all animals, by applying a uniform layer of 50 g 2 times a day to the surface of the udder. At the beginning and end of treatment, blood was taken in each group for general blood test; milk was taken to assess bacterial contamination and assess the number of somatic cells. The clinical assessment of the condition of the animals was carried out daily. All the animals were kept in the same conditions. The diet of cows of all groups corresponded to the norms for this type and technological use of animals. The presence of pathology and the effectiveness of the drug were evaluated based on the results of a clinical examination of animals, the results of bacteriological analysis, a general blood test and a milk test for the number of somatic cells. As a result of the work carried out, based on the results of the study, it was found that the drug showed high therapeutic efficacy in various forms of mastitis caused by opportunistic microflora in lactating cows, and also helps to restore the qualitative characteristics of milk and reduce somatic cells in them.