Producing Dairy Cows Research Articles

Cavitated concentrates as a stimulating factor for the productivity of dairy cows

The article presents the results of the experiment on the positive effect of cavitated concentrates (grain mixture and wheat bran) in the diet of dairy cows of the Red Steppe breed on nutritional value, palatability and bioavailability of nutrients. Biochemical analysis of cavitated grain mixture and wheat bran, in terms of dry matter of the original raw materials indicates that with equivalent energy values, there were some changes in biochemical indicators. Thus, the content of crude protein and crude fat increased by 8.5 and 2.5%; 6.4 and 1.09% in favor of cavitated feeds. The content of crude fiber and starch in the grain mixture decreased by 3.5 and 3.7%, in wheat bran - by 19.4 and 3.9%. The increase for sugars in the grain mixture was 15.2 g, in wheat bran - by 6.2 g. The feed intake of the diet, on average during the experiment compared to the control, was higher in cows of the I and II experimental groups: for roughage - by 2.3 and 3.7%, for succulent - 3.6 and 6.0%. During the record period of the experiment, the milk productivity of cows receiving a diet with traditional concentrate preparation was 2070 kg, which is 22.9% less than that of their peers receiving a cavitated grain mixture with the diet, and 26.2% less than that of animals receiving cavitated wheat bran. At the same time, having small differences in the content of fat and protein in milk (3.48-3.55% and 3.28-3.30%), the increase in milk yield in experimental groups I and II affected the yield of "milk fat" and "protein mass fraction". Thus, these indicators were 72.45 in the control, 90.35 in I and 90.88 kg and 68.1; 84.0; 85.7 kg in II, which is higher in comparison with the control by 24.7 and 23.3%; 25.4 and 25.8%. A positive relationship was revealed between the content of metabolizable energy in the diet and daily milk yield, with an increase in this indicator in the diet by 2.51 and 2.76%, the daily milk yield increased by 22.9 and 26.2%, respectively. A high positive correlation was found between the amount of protein in milk and the sugar content in the diet (r=0.99), indicating a high degree of interdependence. The content of exchange energy in the diet correlated with the amount of fat in daily milk yield (r=0.99).

Effect of medium-chain fatty acids supplementation on feed intake, rumen fermentation, blood profile, and milk production of dairy cows in the transition period.

Medium-chain fatty acids (MCFAs) are rapidly utilized by the liver as an energy source. However, the effects of feeding MCFAs to dairy cows during the transition period and the subsequent effect on postpartum performance is not well clear. Therefore, this study was to evaluate the effects of MCFAs supplementation on feed intake, rumen fermentation, blood profile, and milk production in dairy cows during their transition period. Twenty-one multiparity Holstein cows were randomly assigned to 2 dietary groups: one group received a diet supplemented with MCFAs calcium salts (MCFA-Ca) from 3 weeks relative to expected parturition to 5 weeks postpartum (MCFA; n = 10), and the other group received the same diet without supplements (control; n = 11). MCFA-Ca containing 80% caprylic acid and 20% capric acid were added to the mixed diet at 1.5% dry matter. During the close-up period (from 3 weeks relative to expected parturition until parturition), cows were fed a TMR with restricted intake to provide 100% of the metabolic energy requirement. Subsequently, the cows were fed a TMR ad libitum from parturition to 5 weeks postpartum. The dry matter intake and body weight did not differ throughout the experimental period between groups. Rumen fermentation and protozoa counts remained unaffected during the experimental period. Supplementation of MCFA had no effect on the plasma concentrations of nonesterified fatty acids and total ketone bodies in cows throughout the experimental period. On the other hand, postpartum plasma glucagon concentration was higher in the MCFA group than in the control group, and milk yield tended to increase in the MCFA group. In conclusion, our results suggested that MCFA-Ca supplementation enhances the catabolic state by affecting pancreatic hormone secretion, resulting in an increase in milk yield during the fresh period without an excessive negative energy balance in dairy cows.

Effects of Dietary Starch Concentration on Milk Production, Nutrient Digestibility, and Methane Emissions in Mid-Lactation Dairy Cows

Effects of Dietary Starch Concentration on Milk Production, Nutrient Digestibility, and Methane Emissions in Mid-Lactation Dairy Cows

Heat Stress in Dairy Cows: Impacts, Identification, and Mitigation Strategies-A Review.

Heat stress in animals affects productivity, health, and reproduction, with particularly pronounced effects in dairy cows. Identifying heat stress requires understanding both physiological and environmental indicators, such as increased heart rate, respiratory rate, and rectal temperature, which reflect the animal's thermal condition within its environment. Thermoregulation in cows involves behavioral and physiological adjustments to maintain homeothermy, aiming to stabilize their internal thermal state. To assess the thermal condition of animals, machine learning models have been developed, leveraging both environmental and physiological indicators for more accurate stress detection. Among the various indices of thermal environment, the Temperature and Humidity Index (THI) is the most widely used. Cooling strategies for animals and their environments are essential to mitigate the effects of heat stress. One effective approach involves the use of evaporative adiabatic cooling combined with forced ventilation systems in feeding alleys and pre-milking holding areas. This method enhances evaporative exchanges and facilitates heat dissipation between the animal and its surroundings, thereby alleviating heat stress and improving both the welfare and productivity of dairy cows.

Development and evaluation of optimized PCR and indirect ELISA for the detection of Morganella morganii in dairy cows.

Morganella morganii (M. morganii) is a Gram-negative opportunistic pathogen, whose increasing virulence and antibiotic resistance negatively impact dairy cow health and productivity, raising concerns in livestock health management. To mitigate this risk, rapid and reliable diagnostic methods for detection are essential. Currently, detection methods for M. morganii are underdeveloped, prompting us to develop both pathogenic and serological detection methods, including an optimized PCR technique and an indirect enzyme-linked immunosorbent assay (I-ELISA). The optimized PCR method utilized bacterial suspensions directly as templates, bypassing the need for DNA extraction and thereby allowing the direct detection of M. morganii in fecal samples. Primer concentrations and annealing temperatures were optimized to minimize primer dimer formation, ensuring high specificity. Clinical evaluation was conducted using 771 fecal and nasal fluid samples collected from dairy farms in five regions. The I-ELISA method was developed using M. morganii lipoprotein (LPP) antigen. Parameters such as antigen coating, blocking conditions, and antibody dilution were optimized to improve specificity. Stability and reproducibility were validated through intra- and inter-assay tests. A total of 476 serum samples from dairy cows were tested to assess the method's clinical applicability. The optimized PCR method demonstrated high sensitivity and specificity, achieving a detection threshold of 0.2 CFU/μL. Clinical testing revealed a positivity rate of 1.4% among 771 fecal and nasal fluid samples. The I-ELISA method showed excellent stability and reproducibility, confirmed through intra- and inter-assay consistency. In testing 476 dairy cow serum samples, the positivity rate for M. morganii was 5.9%. These results indicate the utility of I-ELISA as a reliable serological diagnostic tool. The PCR and I-ELISA methods collectively offer practical solutions for the early clinical diagnosis of M. morganii infections in dairy cows. The PCR technique's efficiency and sensitivity make it ideal for pathogen detection in fecal samples, while the I-ELISA method provides a robust platform for serological analysis. Together, these tools enable timely intervention, contributing to improved livestock health management and mitigating the negative impacts of M. morganii on dairy cow productivity. Future research may focus on further refining these techniques and exploring their applications in broader livestock management contexts.

The supply of branched-chain amino acids and branched-chain keto acids alter lipid metabolism, oxidative stress, and apoptosis in primary bovine hepatocytes.

Fatty liver impairs liver function and reduces productivity in dairy cows. Our previous in vivo findings demonstrated that branched-chain amino acids (BCAA) or branched-chain ketoacid (BCKA) improved liver function and lactation performance in dairy cows; however, the underlying mechanisms remain unclear. This study aimed to assess the impact of BCAA or BCKA supplementation on intracellular triglyceride (TG) accumulation, lipid metabolism, antioxidant response, and apoptosis in hepatocytes. Treatments were: control (CON): customized medium with amino acids, volatile fatty acids, fatty acids (FA), glucose, choline, insulin, and albumin concentrations equal to circulating levels in cows 4d postpartum; BCAA: CON + 33% additional BCAA of plasma BCAA 4d postpartum; and BCKA: CON + 33% additional BCKA of plasma BCAA 4d postpartum. Compared to CON, BCAA and BCKA reduced intracellular TG concentration by 32% and 40%, respectively, after 72 h. BCAA and BCKA enhanced the uptake of palmitic acid, but upregulated the expression of genes regulating FA oxidation. Although mitochondrial membrane potential was reduced, oxidative protein damage (protein carbonyl levels) was decreased in BCAA- and BCKA-treated hepatocytes without changes in mitochondrial copy number. Additionally, compared to CON, BCAA and BCKA decreased the expression of executioner caspases (caspase 3 and caspase 7) and reduced the portion of hepatocytes with activated caspase 3/7, suggesting reduced apoptosis. These findings suggest that BCAA or BCKA supplementation improves hepatocyte lipid metabolism, antioxidant defenses, and apoptosis regulation, potentially mitigating the adverse effects of fatty liver. These mechanisms likely underlie the previously observed improvements in liver function and lactation performance.

Influence of Repeated Regrouping on Productivity and Physiological Parameters of Dairy Cows

Influence of Repeated Regrouping on Productivity and Physiological Parameters of Dairy Cows

Effects of including a palmitic acid-enriched supplement in low and high starch diets on milk production and energy partitioning of primiparous and multiparous dairy cows between mid and late-lactation.

The aim of our study was to assess the effects of low or high-starch diets with or without palmitic acid (C16:0) supplementation on the yield of milk, milk components, and energy partitioning of primiparous and multiparous dairy cows between mid and late-lactation. Thirty-two Holstein cows, 12 primiparous ([mean ± SD] 163 ± 33 d in milk) and 20 multiparous ([mean ± SD] 179 ± 37 d in milk), were used in a split-plot Latin square design. Parity was considered the main plot, and within each plot, treatments were then randomly assigned in a replicated 4 × 4 Latin square with 21 d periods and balanced for carryover effects. Treatments were in a 2 × 2 factorial arrangement of dietary starch level and fatty acid (FA) supplementation as main factors. The starch factor comprised either low (LS; 16% of diet dry matter [DM]) or high (HS; 32% of diet DM) dietary starch. Dietary starch was altered by varying the proportion of ground corn, whole cottonseed, and soyhulls, with LS and HS diets containing ∼15 and 18% forage neutral detergent fiber (fNDF) and ∼37 and 25% neutral detergent fiber (NDF), respectively. The FA supplementation factor consisted of either control with no FA supplementation (CON) or a C16:0-enriched supplement at 1.5% of diet DM replacing soyhulls (PALM). Compared with LS, HS increased plasma insulin (0.20 μg/L) and energy partitioning to body reserves (2.04 percentage-units), tended to increase body condition score (BCS) and body weight (BW) change, and decreased dry matter intake (DMI; 1.10 kg/d), milk fat yield (0.04 kg/d) and milk urea nitrogen (MUN; 2.10 mg/dL). Compared with CON, PALM increased energy output to milk (1.10 Mcal/d), the yields of milk fat (0.10 kg/d), 3.5% fat-corrected milk (FCM; 1.90 kg/d) and energy corrected milk (ECM; 1.60 kg/d), and had no effect on BW-related variables. We observed a 3-way interaction between parity, starch, and FA supplementation affecting multiparous but not primiparous cows, where PALM increased plasma insulin concentration (0.14 μg/L) in LS but had the opposite effect in HS by tending to decrease insulin. Our results demonstrate important interactions between parity, starch levels, and FA supplementation. Overall, feeding a low-starch diet to mid and late-lactation dairy cows helped prevent excessive body condition and weight gain while increasing milk fat yield compared with a high-starch diet. Multiparous cows may benefit the most from a low-starch diet as multiparous cows seemed more prone to accumulating body reserves. Feeding a C16:0-enriched supplement increased milk fat yield and ECM without increasing weight gain, regardless of starch level or parity.

The platelet and plasma proteome and targeted lipidome in postpartum dairy cows with elevated systemic inflammation

Unregulated, systemic inflammation negatively impacts health and production in dairy cows. Soluble mediators and platelets have been studied for their expansive role in mediating inflammation. Our objectives were to compare the plasma oxylipin and endocannabinoid profiles, and the platelet and plasma proteomic profiles of healthy cows to cows experiencing elevated systemic inflammation as indicated by plasma haptoglobin (Hp) concentrations. Postpartum cows at 3 DIM with plasma Hp concentrations 0.50 g/L and no clinical disease were enrolled into the high-inflammation group (n = 8). Cows with plasma Hp concentrations 0.1 g/L and no clinical disease were enrolled into the low-inflammation group (n = 8). Targeted lipidomic analysis revealed differences in the plasma oxylipin and endocannabinoid profile between high- and low-inflammation cows. Cows in the high-inflammation group had increased plasma concentrations of the oxylipins 9(S)-HpOTrE, 9(S)-HOTrE, 13(S)-HpOTrE, and 9,10-EpOME, and the endocannabinoid anandamide. In-depth proteomic analysis of platelets between the high- and low-inflammation groups revealed significant differences in protein categories related to platelet granule release and cellular iron uptake. Proteomic outputs from plasma revealed 24 proteins to be different between high and low-inflammation groups, including proteins involved in autophagy and immune mediation. Together, our results indicate that cows experiencing an exacerbated systemic inflammatory response in the postpartum may have impaired disease resistance, and platelets could be contributors to their inflammatory state.

Heat Tolerance-Associated circRNA3685 Regulates Apoptosis and Autophagy in Bovine Mammary Epithelial Cells via Sponging bta-miR-138.

Heat stress negatively affects dairy cow production, and health, leading to significant losses. Identifying mechanisms associated with heat tolerance is crucial for developing breeding strategies. Circular RNAs (circRNAs), a type of noncoding RNA, regulate cell functions like autophagy, apoptosis and proliferation. In this study, dairy cows were classified into heat stress tolerant (HST, n = 15) and heat stress sensitive (HSS, n = 15) groups based on respiratory and drooling score during the heat stress. A significant difference in milk production decline was observed, with the HST group showing less decline, indicating better heat tolerance. Blood transcriptomics analysis identified 166 differentially expressed circRNAs with circRNA3685 being highlighted as a key candidate linked to heat tolerance. Overexpression of circRNA3685 in bovine mammary (MAC-T) cells inhibited autophagy and apoptosis. The circRNA3685 was found to interact with bta-miR-138, targeting HIF1A. These findings provide insights into circRNAs' role in heat stress adaptation in dairy cows.

In vivo evaluation of selenium-tellurium based nanoparticles as a novel treatment for bovine mastitis

BackgroundBovine mastitis is one of the main causes of reduced production in dairy cows. The infection of the mammary gland is mainly caused by the bacterium Staphylococcus aureus, whose resistant strains make the treatment of mastitis with conventional antibiotics very difficult and result in high losses. Therefore, it is important to develop novel therapeutic agents to overcome the resistance of mastitis-causing strains. In this study, novel selenium-tellurium based nanoparticles (SeTeNPs) were synthesized and characterized. Their antibacterial activity and biocompatibility were evaluated both in vitro and in vivo using a bovine model. A total of 10 heifers were divided into experimental and control groups (5 animals each). After intramammary infection with methicillin resistant S. aureus (MRSA) and the development of clinical signs of mastitis, a dose of SeTeNPs was administered to all quarters in the experimental group.ResultsBased on in vitro tests, the concentration of 149.70 mg/L and 263.95 mg/L of Se and Te, respectively, was used for application into the mammary gland. Three days after SeTeNPs administration, MRSA counts in the experimental group showed a significant reduction (P < 0.01) compared to the control group. The inhibitory effect observed within the in vitro experiments was thus confirmed, resulting in the suppression of infection in animals. Moreover, the superior biocompatibility of SeTeNPs in the organism was demonstrated, as the nanoparticles did not significantly alter the inflammatory response or histopathology at the site of application, i.e., mammary gland, compared to the control group (P > 0.05). Additionally, the metabolic profile of the blood plasma as well as the histology of the main organs remained unaffected, indicating that the nanoparticles had no adverse effects on the organism.ConclusionsOur findings suggest that SeTeNPs can be used as a promising treatment for bovine mastitis in the presence of resistant bacteria. However, the current study is limited by its small sample size, making it primarily a proof of the concept for the efficacy of intramammary-applied SeTeNPs. Therefore, further research with a larger sample size is needed to validate these results.

Can dietary palmitic supplementation and milking frequency modify the cheesemaking properties of milk?

Palmitic acid (PA) supplementation and greater milking frequency can increase milk production and fat yield in dairy cows. However, the technological impacts of those practices on cheesemaking still need to be determined. This work aimed to evaluate, with Holstein dairy cows, the effects of dietary PA, thrice-daily milking frequency, and their interaction on cheese yield and composition. Before cheesemaking, milks were standardized to a casein-to-fat ratio of 0.78 ± 0.02 and targets of 3.27 ± 0.03 and 4.20 ± 0.05% wt/wt, for casein and fat concentrations, respectively. Rennet coagulation properties of standardized milk, cheese composition, curd draining properties, free fatty acid (FFA) content, and proteolysis during ripening were analyzed. Dietary PA supplementation modified the milk fatty acid profile but did not affect coagulation and draining properties, cheese composition, and proteolysis. The moisture-adjusted yield and fat and protein recoveries were also similar between treatments. The greater milking frequency did not affect process performance. However, increasing milking frequency led to a significantly higher FFA content in cheese at the end of ripening of 1.4 ± 0.2 vs. 0.8 ± 0.2 mEq/kg of cheese fat for thrice- and twice-daily milkings, respectively. Consequently, dietary supplementation of PA to dairy cows only had a limited effect on the cheesemaking process under the standardized conditions tested. However, the effect of FFA on cheese sensory properties should be considered if the milking frequency is increased.

Effect of phytogenic feed additives (Herb-All- COOL) on milk production and fertility of dairy cows in hot seasons

Effect of phytogenic feed additives (Herb-All- COOL) on milk production and fertility of dairy cows in hot seasons

Biorefined perennial ryegrass press cake as an alternative feed for dairy cows in late lactation and during the dry period: a demonstration

Abstract To investigate the potential application of replacing a proportion of a perennial ryegrass (PRG) silage diet with press cake on productivity and enteric methane (CH4) emissions in late lactation and non-lactating spring-calving dairy cows, a study was undertaken in which control cows (n = 21) were offered PRG silage, while treatment cows (n = 21) were offered a diet consisting of 60% PRG press cake and 40% of the same PRG silage. Although treatment cows had higher group average dry matter intakes (DMI) and produced more enteric CH4, carbon dioxide (CO2), milk solids, protein, fat- and protein-corrected milk yield (FPCM) in late lactation, the magnitude of the difference between treatment and control cows varied from week to week (P &lt; 0.050). When enteric CH4 per kg of milk yield, milk solids and FPCM were considered, there was no significant difference between treatment and control. Absolute enteric CH4 was higher for cows fed press cake during the non-lactating period but this tended to vary from week to week. Similarly, CO2 (P &lt; 0.001) and hydrogen (H2; P = 0.023) differed from week to week for cows offered press cake, and cows offered PRG silage in the non-lactating period. Although there was no significant effect of diet on body weight (BW) and body condition score (BCS), when enteric CH4 was expressed on a per kg BW basis, cows offered press cake tended to produce more enteric CH4 in both late lactation and during the dry period.

Effects of different doses of 3-nitrooxypropanol combined with varying forage composition on feed intake, methane emission, and milk production in dairy cows.

The objective of this study was to investigate the effect of combining different doses of 3-nitrooxypropanol (3-NOP) with varying forage composition on gas emission and production performance of dairy cows. Seventy-two lactating Danish Holstein cows (36 primiparous and 36 multiparous) were enrolled in a continuous randomized block design with an initial 2-week covariate period followed by application of treatments for 12 consecutive weeks. Initial DMI and ECM yield were 23.8 ± 3.34 (mean ± SD) and 38.3 ± 7.12 kg/d, respectively. Cows were blocked according to parity and DIM. Treatments were organized in a 2 × 3 factorial arrangement. The first factor was diet type, reflecting 2 different forage compositions of the diet. Ratio of grass-clover silage to corn silage was 60%:40% of total forage DM in grass-based diets and 40%:60% in corn-based diets. In total, forage constituted 56% of the DM in the partial mixed rations. The second factor reflected 3 doses of 3-NOP: 0, 60, or 80 mg 3-NOP/kg DM. Gas emissions were measured using GreenFeed and feed intake by using Insentec. Weekly averages from the last 10 weeks were analyzed by using a mixed model including fixed effects and interactions among diet type, 3-NOP dose, week, and parity, and included a covariate term and accounted for repeated measures. Methane yield (g/kg DMI) was reduced by 34 and 31%, and CH4 intensity (g/kg ECM) was reduced by 34 and 32% at 60 and 80 mg 3-NOP/kg DM, respectively, and there was no difference in CH4 yield or intensity between the 2 doses. The corn and grass based diets were similar in NDF and starch levels, and there was no interaction between dose of 3-NOP and diet type for CH4 yield or intensity. Total DMI was reduced by 9% in cows fed 80 mg 3-NOP/kg DM across diet types, whereas there was no effect on DMI at 60 mg 3-NOP/kg DM. Similarly, ECM yield was reduced by 5% in cows fed 80 mg 3-NOP/kg DM compared with no 3-NOP supplementation, and these cows had a 42% lower BW increase over the experiment compared with no supplementation. In conclusion, 3-NOP at 60 mg/kg DM was efficient in reducing CH4 without compromising feed intake and milk production, while 80 mg 3-NOP/kg DM negatively affected production performance.

Responses of dairy cows to weekly individualized feeding strategies for dairy cows regarding their metabolic status

In dairy farms, cows are commonly fed a mixture of forages and concentrates ad libitum. To improve the energetic status and productivity of dairy cows, individualized feeding strategies have been proposed. One of this strategy is providing supplemental concentrates to adjust the forage-to-concentrate ratio based on factors like individual milk yield or calculated energy balance. This strategy can affect milk production and cow health, though consistent rules for adjustment are lacking. The objectives of this study were to evaluate the effects of an individualized feeding strategy, adjusted weekly based on the body weight gain of dairy cows, on production performance; and to determine if the metabolic status of the cows could be predicted early in lactation to take it into account into the decisions rules of the strategy. A total of 40 multiparous Holstein cows were involved in a 4-mo trial. The cows entered the experiment individually after calving and were initially fed a standard ration with a fixed 3 kg of extra concentrate per day for the first 8 d (on average). The cows were then paired based on calving date, parity (2 or 3), and body weight gain over the initial week. One cow from each pair was assigned to the Standard Feeding (SF) strategy, which continued receiving the fixed ration, while the other was assigned to the Precision Feeding (PF) strategy, which received a variable amount of extra concentrate adjusted weekly based on body weight gain. Measurements included weekly body weight, daily milk yield, and daily intakes of concentrates and forages. Blood samples were collected to measure metabolites (glucose, BHB, NEFA) for metabolic profiling. The results showed no significant differences in overall body weight gain, milk yield, or intakes (concentrates and/or forages). Two metabolic clusters were identified based on blood metabolites (glucose, BHB, NEFA), predicting cows' metabolic status with 90% accuracy. The balanced cluster had higher milk production, feed intake, and lost more body weight than the imbalanced cluster. Alternative variables like body weight gain and total feed intake can be used to predict metabolic clusters, achieving up to 70% accuracy. To conclude, cows fed this precision feeding strategy had similar performances than those fed the standard feeding strategy. Long-term effect of this strategy should be studied. Metabolic profiling predicted cows' metabolic status suggesting its potential for enhancing individualized feeding decisions.

Accuracy and precision of diets fed to close-up cows on dairy farms and its association with early lactation performance

Ensuring a consistent ration is critical for maximizing lactating cow performance, but this is not known for dry cows. The objectives of this cohort observational study were to: 1) characterize close-up dry cow diets fed on commercial farms in Ontario, Canada, 2) describe the accuracy of the nutrient composition between the formulated close-up diet and the diet offered to the cows, 3) describe the precision of the close-up diets across time, and 4) explore potential associations of that accuracy and precision with blood metabolic parameters and milk yield of cows in early lactation. Forty free-stall dairy farms were visited once every 4 wk, for a total of 6 visits to each farm, from April to October 2022. At each visit, samples of the close-up diet were collected and analyzed for dry matter (DM) content and chemical composition. Close-up diet formulations were also obtained by each farm's nutritionists. During each visit, fresh cows (0 to 14 d in milk [DIM]) had blood samples taken for blood metabolites. The same cows were also monitored for milk yield up to 120 DIM. Multivariable models were used to analyze associations between variability (in relation to the formulated diet and across time) of nutrients in the close-up diet, as measured by coefficient of variation (CV), and outcomes in fresh cows. Corn silage (67.6% of farms) and straw (24.3% of farms) were the predominant primary forage sources used in the close-up dry cow diets. Soybean meal (37.8% of farms) and canola meal (18.9% of farms) were the main ingredients used as primary concentrate sources. Overall, the diets offered did not accurately represent the formulated diets. With the exception of net energy for lactation (NEL), the CVs for the other nutrients were all greater than 5%. Diet variability, both between fed and formulated diets and from visit to visit during the close-up period, was associated with metabolic markers and dairy cow production. Lower variability in non-fiber carbohydrates (NFC) between the fed and formulated diets was associated with better liver health index scores. Visit-to-visit variability in fat% and NFC% were associated with blood β-hydroxybutyrate (BHB) concentrations, while NFC% variability was associated with blood glucose levels. Serum nonesterified fatty acids (NEFA) concentrations were associated with visit-to-visit variability in DM% and CP%. These results underscore the importance of maintaining consistency between diet formulations and feeding practices over time to optimize early-lactation dairy herd performance and health, granted that these diets are correctly formulated to meet the nutritional needs of cows in the close-up period and applied with recommended feeding practices.

Effects of raw and roasted high oleic soybeans on milk production of high-producing dairy cows

Processing method of soybeans has the potential to influence dairy cow production performance, therefore we determined the effect feeding raw or roasted, ground high oleic acid soybeans (HOSB) on production responses of high-producing dairy cows. Thirty-six multiparous Holstein cows (45.6 ± 6.22 kg/d of milk; 110 ± 61 DIM) were randomly assigned to treatment sequences in a 4 × 2 Truncated Latin square design with 35-d periods. Treatments were: 1) control diet containing soybean meal and soybean hulls (CON), 2) 16% roasted and ground HOSB (RST), 3) 16% raw and ground HOSB (RAW-D), and 4) 16% raw and ground HOSB + additional rumen by-pass protein (RAW-U). High oleic acid soybeans replaced conventional soybean meal and hulls in the control diet and rumen by-pass protein replaced soybean meal in RAW-U to maintain diet nutrient composition (%DM) of ∼28.0% NDF, 21.3% forage NDF, 27.3% starch, and 17.8% CP. Fatty acid content of CON, RST, RAW-D, and RAW-U was 1.60, 4.30, 4.36, and 4.34%DM, respectively. Pre-planned contrasts included the overall effect of HOSB inclusion {CON vs. HOSOY [1/3 (RST + RAW-D + RAW-U)]}, the effect of soybean processing {RST vs. RAW [1/2 (RAW-D + RAW-U)]}, and the effect of increasing RUP content within the raw HOSB treatments (RAW-D vs RAW-U). For most variables tested, there were significant interactions between treatment and week, as HOSOY increased production variables compared with CON and RST increased production responses compared with RAW, with only the magnitude of difference varying between weeks. Overall, HOSOY increased DMI and yields of milk, 3.5% FCM, ECM, and milk fat, but did not affect milk protein yield. RST did not impact DMI but increased yields of milk, 3.5% FCM, ECM, milk fat, and milk protein. Compared with RAW-D, RAW-U increased yields of milk and milk protein and tended to increase ECM. Overall, HOSB inclusion of 16% DM increased production responses in high-producing dairy cows, but roasted HOSB had a greater impact than raw HOSB, and the addition of rumen-bypass protein positively affected milk protein response.

Milk production and methane emissions from dairy cows fed silages from different grassland species and harvesting frequencies.

The aim of this study was to examine how silages from different grassland species and harvesting frequencies affect feed intake, milk production, and methane (CH4) emission in dairy cows. We hypothesized that cows consuming silages of more frequent harvest, grass species with greater organic matter digestibility and legumes with lower NDFom concentration would have greater silage dry matter intake and milk yield and thereby lower CH4 yield and intensity. Forty Norwegian Red cows were allocated to 5 treatments in a cyclic changeover design with 4 21-d periods (14 d of adaptation, 7 d of data collection). The 5 treatments evaluated were silages produced from timothy (Phleum pratense L.) in a 3-cut system (T3), timothy in a 2-cut system (T2), perennial ryegrass (Lolium perenne L.) in a 3-cut system (PR3), red clover (Trifolium pratense L.) in a 3-cut system (RC3) and a mix of T3 and RC3 (50:50 on DM basis) (T3/RC3). The treatments were prepared by mixing silages from each crop over the growing season, proportional to the harvested DM yield of each cut. Cows were offered the mixed silages ad libitum supplemented with a fixed level of concentrate. Gas emissions were measured using 2 Greenfeed units. Milk yield was recorded in the milking robot at each visit, and milk samples were collected at 3 consecutive milkings during the last 7 d of each period. Cows were weighed after each milking, and total-tract digestibility of each diet was estimated using acid insoluble ash as internal marker in fecal grab samples. The data were analyzed using the MIXED procedure of SAS with block, period and treatment as fixed effects and animal within block as random effect. Silage and total DMI did not differ between T3 and T2, but total DMI was lower for PR3 than for T3. There was a quadratic effect of increased proportion of red clover, with highest intakes of T3/RC3 and lower intakes of RC3 than of T3. Energy corrected milk (ECM) yield was lower for T2 than T3, and for PR3 than T3. There was a quadratic effect of increased proportion of red clover, with highest ECM yield in T3/RC3 and lower in RC3 than in T3. Organic matter digestibility was lower for T2 than T3, but it did not differ between T3 and PR3. Including red clover in the diet linearly decreased organic matter digestibility. Methane production (g/d) did not differ between T3 and T2, but CH4 intensity (g/kg ECM) was greater for T2 than for T3. There was no difference between T3 and PR3 for CH4 production but yield and intensity were greater for PR3 than T3. Including red clover in the diet linearly increased CH4 production, yield and intensity with greatest intensity in the 100% red clover diet. In conclusion, changing harvesting frequency for timothy from 2 to 3 harvests per year did not affect CH4 production or yield, but CH4 intensity was reduced. Replacing timothy with perennial ryegrass and increased inclusion rate of red clover both increased CH4 yield and intensity.

Reducing dietary crude protein levels while meeting metabolizable protein requirements: Performance of dairy cows over a full lactation period.

A total of 90 Holstein dairy cows (24 primiparous, 66 multiparous, mean parity = 3.0) were fed diets containing either 150, 160, or 170 g CP/kg DM from 8 to 180 DIM, with all diets designed to supply at least 100% MP requirements. On d 181, half of the cows in each treatment changed to a diet containing 140 g CP/kg DM (supplying 100% MP requirements), with the remaining cows continuing to be offered their original treatment diets. This resulted in 6 treatments in the mid-late lactation period (181-280 DIM): 150, 150/140, 160, 160/140, 170, and 170/140 g CP/kg DM. Decreasing dietary CP concentration from 170 to 150 g CP/kg DM did not affect DMI, milk yield, milk fat or protein yield in early lactation (8-181 DIM), but reduced MUN and the ratio of n-6 to n-3 fatty acids in milk, as well as serum albumin, globulin, total protein, and urea concentrations. In addition, reducing dietary CP content from 170 to 160 g CP/kg DM improved N use efficiency (NUE; milk N/N intake), with no further improvement with 150 g CP/kg DM. Treatment had no effect on apparent total-tract ration digestibility in early lactation. Urinary N output decreased with decreasing dietary CP content in early lactation, whereas manure N (fecal N plus urinary N) output increased. Urinary N/manure N decreased from 170 to 160 g CP/kg DM diet, whereas no further reduction was observed with the 150 g CP/kg DM diet. Cows that remained on the 150 g CP/kg DM treatment in mid-late lactation (181-280 DIM) had a lower DMI than those which remained on the diet containing 170 g CP/kg DM. Reducing the dietary CP concentration to 140 g CP/kg DM in mid-late lactation reduced DMI, milk yield, and milk fat and protein yields, compared with offering the 170 or 160 g CP/kg DM diet throughout lactation, possibly reflecting a response to oversupply of MP with the latter treatments, rather than an undersupply of MP with the former, although this is uncertain. Concentrations of C18:2 cis-9,trans-11 and the ratio of n-6 to n-3 fatty acids in milk were lower for cows offered diets containing 140 or 150 g CP/kg DM in mid-late lactation compared with 160 or 170 g CP/kg DM. Reducing dietary CP concentration from 170 to 140 g CP/kg DM improved NUE from 0.28 to 0.34 in mid-late lactation. Nitrogen digestibility was reduced when cows were offered the 140 g CP/kg DM diet compared with the 150 or 160 g CP/kg DM diet. Lowering the dietary CP concentration from 170 to 140 g CP/kg DM in mid-late lactation decreased N output in milk, feces, urine, and manure. These results indicate that a dietary CP content of 160 g CP/kg DM, which met the MP requirement of cows, may be optimal to support performance over a whole lactation, improve NUE, and reduce N excretion, thus contributing to a more sustainable approach to dairy cow production.