High-producing Dairy Cows Research Articles

Increasing the prepartum dose of rumen-protected choline: Effects on milk production and metabolism in high-producing Holstein dairy cows

Peripartum rumen-protected choline (RPC) supplementation is beneficial for cow health and production, yet the optimal dose is unknown. In vivo and in vitro supplementation of choline modulates hepatic lipid, glucose, and methyl donor metabolism. The objective of this experiment was to determine the effects of increasing the dose of prepartum RPC supplementation on milk production and blood biomarkers. Pregnant multiparous Holstein cows (n = 116) were randomly assigned to one of 4 prepartum choline treatments that were fed from -21 d relative to calving (DRTC) until calving. From calving until +21 DRTC, cows were fed diets targeting 0 g/d choline ion (control, CTL) or the recommended dose (15 g/d choline ion; RD) of the same RPC product that they were fed prepartum. The resulting treatments targeted: (1) 0 g/d pre- and postpartum [0.0 ± 0.000 choline ion, percent of dry matter (%DM); CTL]; (2) 15 g/d pre- and postpartum of choline ion from an established product (prepartum: 0.10 ± 0.004 choline ion, %DM; postpartum: 0.05 ± 0.004 choline ion, %DM; ReaShure, Balchem Corp.; RPC1RD▸RD); (3) 15 g/d pre- and postpartum of choline ion from a concentrated RPC prototype (prepartum: 0.09 ± 0.004 choline ion, %DM; postpartum: 0.05 ± 0.003 choline ion, %DM; RPC2, Balchem Corp.; RPC2RD▸RD); or (4) 22 g/d prepartum and 15 g/d postpartum from RPC2 [prepartum: 0.13 ± 0.005 choline ion, %DM; postpartum: 0.05 ± 0.003 choline ion, %DM; high prepartum dose (HD), RPC2HD▸RD]. Treatments were mixed into a total mixed ration, and cows had ad libitum access via a roughage intake control system (Hokofarm Group). From calving to +21 DRTC, all cows were fed a common base diet and treatments were mixed into the total mixed ration (supplementation period, SP). Thereafter, all cows were fed a common diet (0 g/d choline ion) until +100 DRTC (postsupplementation period, postSP). Milk yield was recorded daily and composition analyzed weekly. Blood samples were obtained via tail vessel upon enrollment, approximately every other day from -7 to +21 DRTC, and at +56 and +100 DRTC. Feeding any RPC treatment reduced prepartum dry matter intake compared with CTL. During the SP, no evidence for a treatment effect on energy-corrected milk (ECM) yield was found, but during the postSP, RPC1RD▸RD and RPC2RD▸RD treatments tended to increase ECM, protein, and fat yields. During the postSP, the RPC1RD▸RD and RPC2RD▸RD treatments tended to increase, and RPC2HD▸RD increased, the de novo proportion of total milk fatty acids. During the early lactation SP, RPC2HD▸RD tended to increase plasma fatty acids and β-hydroxybutyrate concentrations, and RPC1RD▸RD and RPC2RD▸RD reduced blood urea nitrogen concentrations compared with CTL. The RPC2HD▸RD treatment reduced early lactation serum lipopolysaccharide binding protein compared with CTL. Overall, peripartum RPC supplementation at the recommended dose tended to increase ECM yield postSP, but no evidence was seen of an additional benefit on milk production with an increased prepartum dose of choline ion. The effects of RPC on metabolic and inflammatory biomarkers support the potential for RPC supplementation to affect transition cow metabolism and health and may support the production gains observed.

Effects of grazing management and concentrate supplementation on intake and milk production of dairy cows grazing orchardgrass

In pasture-based dairy systems, grazing management strategies have focused mainly on achieving a high herbage harvest per hectare, whereas strategies oriented to maximizing the intake rate of herbage have been recently explored. The objectives of the study were (i) to evaluate the herbage nutritional value, intake and milk production per animal and per hectare of mid-lactation Holstein dairy cows grazing orchardgrass (Dactylis glomerata) in response to grazing management strategies that prioritize either herbage harvest per hectare or herbage intake rate, and (ii) to assess whether concentrate supplementation affects this response. The experiment was conducted in Uruguay using twenty-four mid-lactation Holstein dairy cows grazing orchardgrass under rotational stocking over an 81-day period. The experimental design was a randomized complete block with a 2 × 2 factorial arrangement consisting of two grazing management strategies [i.e. “high intake rate” (HIR) with pre- and post-grazing sward target heights of 21 and 13 cm, respectively, vs. “high herbage harvest per hectare” (HHH) with a pre-grazing target of 3.5–4 leaves per tiller and a post-grazing target of minimum leaf area corresponding to sward heights between 7 and 11 cm] in combination with concentrate supplementation levels of 0 (CS0) or 4 (CS4) kg of dry matter/cow per day. Sward height, number of leaves, herbage morphological and chemical composition, body weight (BW), body condition score (BCS), feed intake, and milk production per cow and per hectare were measured. Statistical analyses were performed using linear mixed models. Compared to cows under HHH, cows under HIR grazed herbage with greater nutritional value and achieved a greater feed intake and greater milk production per cow (P < 0.05), regardless of concentrate supplementation level. Conversely, under HHH milk production per hectare was marginally greater (P < 0.10) and milk solids production per hectare was greater (P < 0.05). Yet, cows under HHH lost BCS when were managed without supplementation (P < 0.05). In conclusion, HIR grazing management is an effective option for grazing dairy production systems that seek to maximize individual productivity of high-producing cows. On the other hand, HHH grazing strategies remain relevant to dairy farm businesses in which profit is driven by production per hectare. Yet, high producing dairy cows under this strategy are likely to lose BCS if not supplemented.

Dynamics of chewing and eating behavior, lying behavior, and salivary characteristics associated with duration of high grain feeding in cows with or with no phytogenic supplement

This study evaluated the adaptive changes in chewing and eating behavior, lying behavior, and salivary properties due to the switch from forage to high grain and the duration of high grain feeding in cows, with or without a phytogenic feed additive. Nine non-lactating cannulated Holstein cows were used in a cross-over design with two experimental periods. Each period included one week of forage feeding, one week of diet transition, and four weeks of high grain feeding (35:65 forage to concentrate ratio; DM basis). Cows were either not supplemented (CON) or supplemented with a phytogenic additive (PHY) characterised by menthol, thymol and eugenol. Switching to high grain decreased (P < 0.01) rumination time compared to forage feeding; however, compared to week 2, rumination time increased (P < 0.01) by 73.8 and 53.21 min/d in weeks 3 and 4 on high grain, respectively. In week 4 on high grain, the PHY-supplemented cows tended (P = 0.08) to ruminate (263 vs. 204 min/d) and chew (406 vs. 347 min/d) longer compared to CON counterparts. The change to high grain increased (P < 0.05) sorting for long and medium size feed particles compared to forage diet, and there was a further increase (P < 0.05) in sorting for long and medium size feed particles in week 3 and 4 on high grain compared to the initial stage of the high grain challenge. Interestingly, PHY supplementation contributed to a more uniform intake of the diet by reducing (P < 0.05) the sorting of both medium and fine particles. Compared to week 1, lying time increased (P < 0.05) by 50 min/d in week 3 on high grain. High grain diet decreased (P < 0.05) salivary pH in week 1, while PHY supplementation helped maintaining this variable at physiological level during this initial grain challenge. Salivary bicarbonate was lower (P < 0.05) in weeks 3 and 4 compared to week 2 on high grain. Overall, the switch to high grain and the duration of feeding influenced chewing and eating behavior, lying behavior and salivary characteristics. Effects were still found 3 or 4 weeks after the diet switch; whereas PHY supplementation contributed to a more uniform nutrient intake by decreasing sorting behavior, which was reflected in stabilized salivary pH at the beginning of the grain challenge, and a tendency for increased chewing activity. However, more research is warranted to evaluate the positive role of PHY supplementation in decreasing feed sorting on metabolic health status and welfare of high-producing dairy cows, which are commonly affected due to high grain feeding.

A network meta-analysis of the impact of feed-grade and slow-release ureas on lactating dairy cattle

A network meta-analysis was conducted to determine the effects of feeding feed-grade urea (FGU) or slow-release urea (SRU) as a replacement for true protein supplements (control; CTR) in high-producing dairy cattle diets. Research papers were selected (n = 44) from experiments published between 1971 and 2021 based on the following criteria: dairy breed, detailed description of the isonitrogenous diets fed, provision of FGU or SRU (or both), high-yielding cows (>25 kg/cow per day), and results that included at least milk yield and composition, but data on nutrient intake, digestibility, ruminal fermentation profile, and N utilization were also considered. Most studies compared only 2 treatments, and a network meta-analysis approach was adopted to compare the effects among CTR, FGU, and SRU. Data were analyzed using a generalized linear mixed model network meta-analysis. Forest plots of milk yield were used to visualize the estimated effect size of treatments. Cows included in the study produced 32.9 ± 5.7 L/d of milk, 3.46 ± 5.0% of fat, and 3.11 ± 0.2% of protein with an intake of 22.1 ± 3.45 kg of dry matter. Average diet composition was 1.65 ± 0.07 Mcal of net energy for lactation, 16.4 ± 1.45% CP, 30.8 ± 5.91% neutral detergent fiber, and 23.0 ± 4.62% starch. Average supply of FGU was 209 g/cow per day, whereas the average supply of SRU was 204 g/cow per day. With some exceptions, feeding FGU and SRU did not affect nutrient intake and digestibility, N utilization, and milk yield and composition. However, the FGU reduced the acetate proportion (61.6 vs. 59.7 mol/100 mol) and the SRU reduced the butyrate proportion (12.4 vs. 11.9 mol/100 mol) compared with CTR. Ruminal ammonia-N concentration increased from 8.47 to 11.5 and 9.3 mg/dL in CTR, FGU, and SRU, respectively. Urinary nitrogen excretion increased from 171 to 198 g/d in CTR versus the 2 urea treatments, respectively. The use of moderate doses of FGU in high-producing dairy cows may be justified based on its lower cost.

Observational study on dry period length and its associations with milk production, culling risk, and fertility in Italian dairy farms

From an initial data set involving 84,189 lactations, this research evaluated the relationship between dry period length (DPL) and milk production, culling risk, and fertility. The data set included a total of 48,297 multiparous cow lactation records, with a calving event occurring in 2019 and 2020, belonging to 62 Italian herds with at least 150 cows. The DPL was classified into 5 categories (<40, 40-49, 50-60, 61-70, and >70 d) and these categories were used to establish the association between DPL and the outcome variables. All data obtained were assessed with simple and multiple linear regressions and Cox proportional hazard models. Cumulative milk production at 60 d in milk (DIM) was the highest in DPL categories of 61 to 70 d (2,480.29 kg/cow) and 50 to 60 d (2,474.39 kg/cow), and the lowest in <40 d (2,281.29 kg/cow). Similarly, DPL categories 61 to 70 d (10,830.94. kg/cow) and 50 to 60 d (10,817.48 kg/cow) had the highest 305-d milk production, whereas the <40 d (10,200.96 kg/cow) had the lowest one. The groups with a DPL of 40 to 49 d and >70 d had slightly, but significant, lower milk production both as cumulative 60 DIM and predicted 305-d milk production. Culling risk had a curvilinear behavior, with DPL <40 d and DPL >70 d showing significantly higher odds for culling during the first 60 DIM compared with DPL of 50 to 60 d [relative risk (RR): 1.53; RR: 1.46]. Within the same comparison, DPL of 61 to 70 d also had a slightly higher risk for culling (RR: 1.13). The DPL was associated also with fertility, with DPL of 40 to 49 d and 50 to 60 d having the greatest odds for pregnancy within the first 200 DIM. The DPL of <40, 61 to 70, and >70 d were negatively associated with fertility and showed pregnancy risks of 0.87, 0.95, and 0.94, respectively. This paper reinforces the importance of DPL as we demonstrated its association with milk production, culling, and fertility. Despite being attractive for high production dairy cows, very short dry periods are at the same time also associated with higher culling risk, lower milk production and fertility. Long DPL is detrimental, especially regarding culling and fertility. In summary, reducing variability in DPL and avoiding extremes by improving reproductive performance, maximizing late lactation milk production and making wise decisions on dry-off timing, may lead to better performances and lower early culling under Italian dairy conditions.

Genomic and transcriptomic analyses enable the identification of important genes associated with subcutaneous fat deposition in Holstein cows

Subcutaneous fat deposition has many important roles in dairy cattle, including immunological defense and mechanical protection. The main objectives of this study are to identify key candidate genes regulating subcutaneous fat deposition in high-producing dairy cows by integrating genomic and transcriptomic datasets. A total of 1654 genotyped Holstein cows are used to perform a genome-wide association study (GWAS) aiming to identify genes associated with subcutaneous fat deposition. Subsequently, weighted gene co-expression network analyses (WGCNA) are conducted based on RNA-sequencing data of 34 cows and cow yield deviations of subcutaneous fat deposition. Lastly, differentially expressed (DE) mRNA, lncRNA, and differentially alternative splicing genes are obtained for 12 Holstein cows with extreme and divergent phenotypes for subcutaneous fat deposition. Forty-six protein-coding genes are identified as candidate genes regulating subcutaneous fat deposition in Holstein cattle based on GWAS. Eleven overlapping genes are identified based on the analyses of DE genes and WGCNA. Furthermore, the candidate genes identified based on GWAS, WGCNA, and analyses of DE genes are significantly enriched for pathways involved in metabolism, oxidative phosphorylation, thermogenesis, fatty acid degradation, and glycolysis/gluconeogenesis pathways. Integrating all findings, the NID2, STARD3, UFC1, DEDD, PPP1R1B, and USP21 genes are considered to be the most important candidate genes influencing subcutaneous fat deposition traits in Holstein cows. This study provides novel insights into the regulation mechanism underlying fat deposition in high-producing dairy cows, which will be useful when designing management and breeding strategies.

Effects of fresh-cow grouping strategy and rumen-protected glucose on production performance, reproductive variables and risk of culling in Holstein cows.

The interaction effects of duration of stay in fresh-cow diet and supplementation with rumen-protected glucose (RPG) on productivity of dairy cows are largely unknown. We hypothesised that a faster transition from fresh-cow diet (higher forage:concentrate) to lactation-cow diet (lower forage:concentrate), combined with supplementation of fresh-cow diet with RPG will have positive effects on production and health of dairy cows. To investigate the immediate and long-term effects of length of stay in fresh-cow diet and supplementation with RPG on productive and reproductive performance of high-producing dairy cows. A total of 264 multiparous Holstein cows (average parity ± standard deviation = 3.2± 1.3, ranging from 2 to 6) were used in a 2 × 2 factorially arranged trial. Treatments were the feeding duration of a fresh-cow diet for 14 or 21 days, each combined by daily supplementation of the fresh-cow diet with ground corn grain or RPG product top dressed at 500g/day/head. The earlier transition from fresh-cow to lactation diet resulted in greater milk production from 15 through 21 days in milk (DIM; by 2.28kg/day), and also fat-corrected milk production on 30 and 60 DIM, respectively. Corn grain or RPG supplementation did not affect the average milk production (1 to 21 DIM), as well as milk production and composition on 30 and 60 DIM. Although extent of body condition loss at transition tended to be lesser in cows switching faster to lactation diet, these cows lost more body condition from 30 to 90 DIM. Survival analysis on calving-to-conception interval and time to removal from herd did not find any significant difference across treatments. The positive effects of earlier transition from fresh-cow to lactation diet were evident by greater milk production from 15 through 21 DIM, and fat-corrected milk production (30 and 60 DIM), at the expense of body condition in high-producing dairy cows. A daily topdress of RPG on fresh-cow diet had no immediate or carryover effects on production of dairy cows.

Association between biochemical parameters and ultrasonographic measurement for the assessment of hepatic lipidosis in dairy cows

Hepatic lipidosis (HL) is a serious metabolic disorder that affects transient high-producing dairy cows. However, there are many laboratory methods could help in the assessment of HL in dairy cows, the definite diagnosis of the disease under field conditions remains a challenge because of the non-specificity of clinical parameters. The aim of the study was to investigate the utility of serum biomarkers, and ultrasonography (US) measurement to diagnose HL in dairy cows. Forty Holstein dairy cows underwent physical examination and were divided into three groups: non-HL, mild HL, and severe HL groups based on US findings, and the concentrations of beta-hydroxybutyric acid (BHBA) and nonesterified fatty acids (NEFAs). Ultrasound images showed hyperechoic lesions and increased pixel intensity (PI) values of liver echotexture in the HL groups. A significant increase was observed in mild and severe HL groups in the activity of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT), BHBA, NEFAs, malondialdehyde (MDA), and nitric oxide (NO) while the concentrations of triglyceride (TG), glutathione (GSH), and total antioxidant capacity (TAC) were significantly decreased. The classification accuracy was in the interest of NEFAs (cut off 0.62 mmol/L, sensitivity 82.6%, specificity 91.7%, and an AUC of 0.913) and BHBA (cut off 1.35 mmol/L, sensitivity 91.31%, specificity of 86.4%, and an AUC 0.812) as important diagnostic parameters. This study offers new insights into the importance of serum biochemical parameters and oxidative stress biomarkers especially, AST, NEFAs, BHBA, and GSH with the digital values of US images for prompt use of minimally invasive techniques to diagnose HL under farm conditions. HIGHLIGHTS Serum metabolites and oxidative stress indices could diagnose hepatic lipidosis in dairy cows NEFA and BHBA concentrations and ultrasound digital values can use as a non-invasive way to the classification of hepatic lipidosis degrees in cows under farm condition.

Effects of exogenous amylolytic or fibrolytic enzymes inclusion on in vitro fermentation of lactating dairy cow diets in a dual-flow continuous-culture system

The objective of this study was to determine the effects of including exogenous amylolytic or fibrolytic enzymes in a diet for high-producing dairy cows on in vitro ruminal fermentation. Eight dual-flow continuous-culture fermentors were used in a replicated 4 × 4 Latin square. The treatments were control (CON), a xylanase and glucanase mixture (T1), an α-amylase mixture (T2), or a xylanase, glucanase, and α-amylase mixture (T3). Treatments were included at a rate of 0.008% of diet dry matter (DM) for T1 and T2 and at 0.02% for T3. All treatments replaced the equivalent amount of soybean meal in the diet compared with CON. All diets were balanced to have the same nutrient composition [30.2% neutral detergent fiber (NDF), 16.1% crude protein (CP), and 30% starch; DM basis], and fermentors were fed 106 g/d divided into 2 feedings. At each feeding, T2 was pipetted into the respective fermentor and an equivalent amount of deionized water was added to each fermentor to eliminate potential variation. Experimental periods were 10 d (7 d for adaptation and 3 d for sample collection). Composite samples of daily effluent were collected and analyzed for volatile fatty acids (VFA), NH3-N, and lactate concentrations, degradability of DM, organic matter, NDF, CP, and starch, and flow and metabolism of N. Samples of fermentor contents were collected from each fermentor at 0, 1, 2, 4, 6, and 8 h after feeding to determine kinetics of pH, NH3-N, lactate, and VFA concentrations over time. All data were analyzed using PROC GLIMMIX of SAS (SAS Institute Inc.), and the repeated variable of time was included for kinetics measurements. Treatment did not affect mean pH, degradability, N flow and metabolism, or the concentrations of VFA, NH3-N, or lactate in the effluent samples. Treatment did not affect pH, acetate:propionate ratio, or the concentrations of lactate, NH3-N, total VFA, acetate, propionate, butyrate, isobutyrate, valerate, or caproate. However, the concentration of total VFA tended to change at each time point depending upon the treatment, and T2 tended to have a greater proportion of 2-methylbutyrate and isovalerate than CON, T1, or T3. As 2-methylbutyrate and isovalerate are branched-chain VFA that are synthesized from branched-chain amino acids, T2 may have an increased fermentation of branched-chain amino acids or decreased uptake by fibrolytic microorganisms. Although we did not observe changes in N metabolism due to the enzymes, there could be changes in microbial populations that utilize branched-chain VFA. Overall, the tested enzymes did not improve in vitro ruminal fermentation in the diet of high-producing dairy cows.

Presence of antibodies against Mycobacterium avium subspecies paratuberculosis in Brazilian high-producing dairy herds.

This study aimed to determine the presence of antibodies against Mycobacterium avium subspecies paratuberculosis (MAP) in high-producing dairy cows, the presence of the pathogen in the feces, and the risk factors associated with the disease. Blood and fecal samples were collected from 708 dairy cows over 2years from 54 herds located in five municipalities of Paraná, Brazil. The serum samples were evaluated for the presence of antibodies against MAP using enzyme-linked immunosorbent assay (ELISA). Fecal samples from 100 cows (69 seropositive and 31 seronegative) were assessed using real-time PCR (qPCR) for IS900 of MAP. The herd prevalence of antibodies against MAP was 61.1% (33/54; 95% CI 46.88-74.08), ranging from 12.5 to 80% across the municipalities, and the prevalence in the animals was 9.8% (69/708; 95% CI 7.77-12.15); it ranged from 0 to 87.5% per herd. Only one of the 69 (1.45%) fecal samples from the seropositive cows was positive for the qPCR. The factors associated with the occurrence of paratuberculosis in herds were the use of compost barn system and the type of bed, whereas only the type of bed was associated with the infection of cows. The only risk factor (OR = 2.45; 95% CI 1.03-5.85) associated with the occurrence of paratuberculosis was the introduction of animals purchased from other dairy farms. The prevalence of active infection was low; however, our results demonstrate the presence of MAP in high-producing dairy herds in Paraná state, Brazil.

Effects of Sugar Beet Silage, High-Moisture Corn, and Corn Silage Feed Supplementation on the Performance of Dairy Cows with Restricted Daily Access to Pasture.

Simple SummarySeasonal variations in herbage growth rate and nutrient composition result in low herbage intake which is insufficient to meet the nutritional requirements of cows and limits milk production. The main opportunities for increasing milk production per cow and per ha are a careful pasture management to ensure adequate herbage high-quality and strategic low-cost and high-energy feed supplementation. Supplementation strategies include different combinations of level, type, and processing of supplemental feeds. This study evaluates the effect of supplementation with sugar beet silage, corn silage, or high-moisture corn (HMC) on dairy performance, rumen, and plasma metabolites in dairy cows under conditions of restricted grazing in spring. We found that the supplementation with sugar beet silage allowed milk production, live weight, and fat concentration similar to corn silage and HMC, but with a lower concentration of milk protein than HMC. Results suggest that sugar beet silage can be used as an alternative supplement for high-producing dairy cows under conditions of restricted grazing in the current experiment.A study was undertaken to assess the effect of supplementation with sugar beet silage, corn silage, or high-moisture corn on dairy performance, rumen, and plasma metabolites in dairy cows under conditions of restricted grazing in spring. Eighteen multiparous Holstein Friesian cows, stratified for milk yield (39.4 kg/day ± 3.00), days of lactation (67.0 days ± 22.5), live weight (584 kg ± 38.0), and number of calves (5.0 ± 1.5), were allocated in a replicated 3 × 3 Latin square design. Treatments were as follows: SBS (10 kg DM of permanent pasture, 7 kg DM of sugar beet silage, 4 kg DM of concentrate, 0.3 kg DM of pasture silage, 0.21 kg of mineral supplement); corn silage (10 kg DM of permanent pasture, 7 kg DM of corn silage, 4 kg DM of concentrate, 0.3 kg DM of pasture silage, 0.21 kg of mineral supplement), and HMC (10 kg DM of permanent pasture, 5 kg DM of high-moisture corn, 4.5 kg DM of concentrate, 1.2 kg DM of pasture silage, 0.21 kg of mineral supplement). Pasture was offered rotationally from 9 a.m. to 4 p.m. Between afternoon and morning milking, the cows were housed receiving a partial mixed ration and water ad libitum. The effect of treatments on milk production, milk composition, body weight, rumen function, and blood parameters were analyzed using a linear–mixed model. Pasture dry matter intake (DMI) was lower in SBS than CS (p < 0.05) and similar to HMC, but total DMI was higher in HMC than SBS (p < 0.05) and similar to CS. Milk production for treatments (32.6, 31.7, and 33.4 kg/cow/day for SBS, CS, and HMC, respectively), live weight, and fat concentration were not modified by treatments, but milk protein concentration was lower for SBS compared with HMC (p < 0.05) and similar to CS. B-hydroxybutyrate, cholesterol, and albumin were not different among treatments (p > 0.05), while urea was higher in SBS, medium in CS silage, and lower in HMC (p < 0.001). Ruminal pH and the total VFA concentrations were not modified by treatments (p > 0.05), which averaged 6.45 and 102.03 mmol/L, respectively. However, an interaction was observed for total VFA concentration between treatment and sampling time (p < 0.05), showing that HMC produced more VFA at 10:00 p.m. compared with the other treatments. To conclude, the supplementation with sugar beet silage allowed a milk response and composition similar to corn silage and HMC, but with a lower concentration of milk protein than HMC. In addition, sugar beet silage can be used as an alternative supplement for high-producing dairy cows with restricted access to grazing during spring.

Evaluating Oxidative Stress Parameters, Pepsinogen, and Insulin-like Growth Factor-1 in Dairy Cows with Displacement of Abomasum

Introduction: Displacement of the abomasum (DA) frequently occurs in high-producing dairy cows. It is a multifactorial disease and has an economic impact on dairy farms. This study aimed to investigate the levels of pepsinogen, Insulin-Like Growth Factor-1, and oxidative stress parameters (malondialdehyde and nitric oxide) in DA cases. Materials and methods: Blood samples were taken from 51 dairy cows suspected of DA, referring to the Veterinary Clinic of Shiraz University, Shiraz, Iran, in the summer of 2021. Twenty of them had Left DA (LDA), 6 had Right DA (RDA), 13 had LDA with clinical signs of ulcer of the abomasum, 3 had RDA with clinical signs of ulcer of the abomasum, and 9 of them (3-5 years old) were clinically healthy as control. The serum concentration of pepsinogen, Insulin-Like Growth Factor-1, malondialdehyde, and nitric oxide were measured. Results: The result of the current study showed that the concentration of pepsinogen was higher in cows with DA compared to healthy cows. The concentrations of malonaldehyde, nitric oxide, and IGF-1 were higher in LDA with the abomasal ulcer, compared to other groups. Conclusion: Pepsinogen can be suggested as a predictor parameter for DA. Malonaldehyde, nitric oxide, and IGF-1 can be considered biomarkers in LDA with the abomasal ulcer. However, further studies are needed to find other effective parameters for predicting DA.

Efficiency of Two Protocols of Resynchronization of Estrus and Ovulation in High-Producing Dairy Cows at Peak Lactation

Abstract The reproductive efficiency of the cows was monitored after two resynchronization protocols: Ovsynch (OVS) and Double Ovsynch (DOS). The research initially included 70 HF cows who entered the first synchronization protocol – Presynch. Cows that did not conceive after the first synchronization were divided into two groups and introduced to two resynchronization protocols. In the first group of cows (n=35), the DOS protocol began with the application of GnRH on day 22 after the Presynch TAI (Timed Artificial Insemination), and seven days later pregnancy check-up was done and PGF2α was applied only to non-pregnant cows (n=23), which remained in the study. In the second group of cows, the OVS protocol started on day 32 after Presynch TAI only in non-pregnant animals (n=20). Progesterone (P4) concentration was determined at the time of application of GnRH1, PGF2α and GnRH2 in both groups of cows, and then 30 days after Resynch TAI, ultrasound pregnancy diagnosis was done. A higher percentage of pregnant cows were recorded in the OVS group compared to the DOS group (45% and 35%, respectively). The concentration of P4 in the serum of cows in the DOS group during the first measurement (GnRH1) was significantly higher than the value in cows that did not conceive (p&lt;0.05), while in the third measurement (GnRH2) the average concentration of P4 in conceiving cows was significantly lower (p&lt;0.001) compared to cows that did not coincive. The open days period was significantly longer in pregnant cows that were resynchronized using the DOS protocol compared to cows from the OVS protocol. In conclusion, the OVS protocol of estrus resynchronization in dairy cows proved to be more successful than the DOS protocol. However, considering the advantages the OVS, it is needed to determine which day of the sexual cycle is the best to start resynchronization.

Preliminary Investigation of the Effects of Rosemary Extract Supplementation on Milk Production and Rumen Fermentation in High-Producing Dairy Cows.

Rosemary extract (RE) has been used as an antioxidant in cosmetics and food additives, indicating its potential as a feed additive to improve adaptation in high-producing dairy cows. Here, we investigated the effects of RE supplementation on lactation performance and rumen fermentation in high-producing dairy cows. Thirty multiparous cows were blocked into 15 groups based on milk production and were randomly assigned to one of two treatments: 0 or 28 g/d of RE supplementation to the basic diet per cow. The experiment was conducted over a 74-day period, which included an initial two-week adaptation period. We observed significant increases in milk and milk lactose yields following RE supplementation. Somatic cell count tended to decrease by treatment. Additionally, superoxide dismutase concentration significantly increased and malonaldehyde level decreased after RE supplementation. Sequencing of 16S rRNA revealed that RE supplementation significantly affected the microbial composition and decreased the richness of the microbiota. Specifically, the abundance of the genus Prevotella was significantly decreased by RE supplementation and was correlated with volatile fatty acids in the Mantel test, whereas no significant correlation was found for other genera. Our findings provide fundamental information on the potential for RE as a feed additive for dairy cows to improve antioxidant status and enhance propionate generation.

Superovulation of high-producing Holstein lactating dairy cows with human recombinant FSH and hMG

Superovulation of high-producing dairy cows is a challenging subject in dairy farms with respect to the cost, dose and type of gonadotropin. The objectives of this study were to compare three gonadotropin products: Folltropin-V® (highly purified FSH with porcine origin), Cinnal-f® (recombinant human FSH) and Menotropins® (hMG) for superovulation in high-producing Holstein lactating dairy cows and to investigate the pregnancy outcomes achieved following transferring embryos recovered from donors treated with different gonadotropins. Healthy high-producing Holstein lactating dairy cows (n = 30; milk production: 46.35 ± 8.78 kg; parity: 2–4; days in milk: 80–130 days) without any puerperal problems were selected as donors. On Day 10 after estrus (Day 0 of superovulation), donors (10 cows in each experimental groups) received Folltropin-V® (400 mg NIH, dissolved in 20 ml), Cinnal-f® (20 vials; each vial of 1 ml contains 75 IU Follitropin alfa) and Menotropins ® (20 ampules; each ampule of 1 ml contains 75 IU FSH and 75 IU LH), administered twice daily, in decreasing doses (4,4; 3,3; 2,2; 1,1 ml), over 4 days. On Day 2 of superovulation, donors received 3 doses of prostaglandin F2α analogue, 6 h apart. They were inseminated twice with a frozen semen at 12 and 24 h after standing estrus. Concurrent with the second insemination, donors received 2500 IU hCG (Karma Pharmatech GmbH, Germany). On Day 7 after standing estrus, superovulatory responses (number of CLs, total ova/embryos and transferable embryos) were recorded and Code 1 embryos, recovered from each treated donors, were transferred to synchronized heifers. Pregnancy was detected on Day 30 and 60 after AI. Gestation length, the number and weight of live births were recorded. Data were analyzed using Proc GLM, Proc Mixed and Proc Genmod of SAS. The respective number of corpora lutea, total number of ova/embryos and transferable embryos were not different among donors received Cinnal-f (25.5 ± 3.01, 11.2 ± 2.77, 5.1 ± 0.86), Menotropins (24.0 ± 3.21, 9.0 ± 2.04, 6.3 ± 1.74) and Folltropin-V (20.3 ± 3.21, 8.9 ± 1.90, 5.1 ± 1.16; P > 0.05). Pregnancy rates on Day 30 was similar among treatment groups (P > 0.05). However, pregnancy rates on Day 60 and the number of calves born healthy was less in heifers that received embryos from Cinnal-f treated donors (P < 0.05). In conclusion, Cinnal-f and Menotropins could provide similar superovulatory response to Folltropin-V for superovulation of high-producing Holstein lactating dairy cows.

Metabolic and antioxidant status during transition is associated with changes in the granulosa cell transcriptome in the preovulatory follicle in high-producing dairy cows at the time of breeding

In this study, we hypothesized that early postpartum (pp) metabolic and oxidative stress conditions in dairy cows (particularly those with severe negative energy balance, NEB) are associated with long-term changes in granulosa cell (GC) functions in the preovulatory follicle at the time of breeding. Blood samples were collected at wk 2 and wk 8 pp from 47 healthy multiparous cows. Follicular fluid (FF) and GC were collected from the preovulatory follicle after estrous synchronization at wk 8. Several metabolic and antioxidant parameters were measured in blood and FF, and their correlations were studied. Subsequently, 27 representative GC samples were selected for RNA sequencing analysis. The GC gene expression data of LH-responsive genes and the estradiol:progesterone ratio in FF were used to identify pre- and post-LH surge cohorts. We compared the transcriptomic profile of subgroups of cows within the highest and lowest quartiles (Q4 vs. Q1) of each parameter, focusing on the pre-LH surge cohort (n = 16, at least 3 in each subgroup). Differentially expressed genes (DEG: adjusted P-value < 0.05, 5% false discovery rate) were determined using DESeq2 analysis and were functionally annotated. Blood and FF β-carotene and vitamin E concentrations at wk 2, but not at wk 8, were associated with the most pronounced transcriptomic differences in the GC, with up to 341 DEG indicative for lower catabolism, increased oxidoreductase activity and signaling cascades that are known to enhance oocyte developmental competence, increased responsiveness to LH, and a higher steroidogenic activity. In contrast, elevated blood NEFA concentrations at wk 2 (and not at wk 8) were associated with a long-term carryover effect detectable in the GC transcriptome at wk 8 (64 DEG). These genes are related to response to lipids and ketones, oxidative stress, and immune responses, which suggests persistent cellular stress and oxidative damage. This effect was more pronounced in cows with antioxidant deficiencies at wk 8 (up to 148 DEG), with more genes involved in oxidative stress-dependent responses, apoptosis, autophagy and catabolic processes, and mitochondrial damage. Interestingly, within the severe NEB cows (high blood NEFA at wk 2), blood antioxidant concentrations (high vs. low) at wk 8 were associated with up to 194 DEG involved in activation of meiosis and other signaling pathways, indicating a better oocyte supportive capacity. This suggests that the cow antioxidant profile at the time of breeding might alleviate, at least in part, the effect of NEB on GC functions. In conclusion, these results provide further evidence that the metabolic and oxidative stress in dairy cows early postpartum can have long-term effects on GC functions in preovulatory follicles at the time of breeding. The interplay between the effects of antioxidants and NEFA illustrated here might be useful to develop intervention strategies to minimize the effect of severe NEB on fertility.

A Prospective Cohort Study on the Periparturient Muscle Tissue Mobilisation in High Producing Dairy Cows.

Simple SummaryThe objectives of this study were to (i) investigate the changes in muscle tissue reserves in high producing dairy cows before and after calving, (ii) identify factors associated with these changes, and (iii) describe their possible associations with cattle reproductive performance. Data were collected from 455 cows on three different UK farms. Holstein cows mobilise both fat and muscle tissue reserves before and after calving. Significant differences in the amount of muscle mobilised were identified between farms; this could have been associated with pre calving diets. Higher genetic merit for milk yield was associated with lower muscle tissue reserves. An increased time to first service was described for those animals that mobilised more muscle tissue.Excessive periparturient fat mobilisation and its association with dairy cattle health and fertility is well documented; however, the role of muscle mobilisation has not been studied extensively. The objectives of this study were to (i) investigate the changes in the thickness of the longissimus dorsi muscle in high producing dairy cows during the periparturient period, (ii) identify factors associated with these changes, and (iii) describe their possible associations with cattle reproductive performance. Data were collected from a total of 500 lactations from 455 cows on three different UK farms. Muscle thickness (MT) (Longissimus dorsi) and back fat thickness (BFT) measurements were collected at three different time-points during the periparturient period using ultrasonography. Body condition score (BCS) was also assessed at the same time-points and blood samples were collected for the measurement of non-esterified fatty acids. Farm fertility records were used and genomically estimated breeding values were also available. Associations between variables were analysed with the use of multivariable linear and logistic regression models; Cox proportional hazard analysis was used for fertility outcomes. Muscle thickness decreased pre- to post-calving on all three farms, though they were notable between farm differences. Those animals with a lower BCS pre-calving had a higher MT loss; significant fat mobilisation occurred between the calving and early lactation period. Muscle thickness changes and fat mobilisation were not associated in this study. An increased time to first service was described for those animals that mobilised more muscle tissue. Our study advances the understanding of periparturient muscle tissue mobilisation in dairy cattle and highlights its potential associations with cattle fertility.

The Effect of Early or Late Breeding on Milk Production in High Producing Lactating Dairy Cows

The objective of this study was to compare the effect of early or late breeding on milk production in high producing dairy cows. In this aim, the cows with previous average peak milk yield above 45 kg/d (n = 48) were divided into two groups; Group1 (early bred) included the cows (n = 21) were inseminated between 45 to 75 days in milk (DIM) and Group2 (n = 27; late bred) were inseminated between 76 to 124 DIM. The cows that became pregnant at their first insemination following first estrus selected for the study. Milk yield was recorded every 5 days after calving for the first 45 days then continued for every 15 days for every each cow. Average DIM in early and late bred cows at insemination were 66 (min, 45; max, 75) and 99 (min, 76; max, 124), respectively. Average milk yield up to 271 d was similar between groups, however, average milk yield from 227 to 271 d was lower (P &amp;lt; 0.04) in early bred cows with 26.7 kg/d compare to late bred cows with 30.3 kg/d. Even, there was no relationship between average milk yield up to 271 d, peak milk yield and day of insemination, it may be concluded that milk yield continues with more pronounced stability through the end of lactation in late bred high yielding cows.

Feed intake, rumen fermentation and performance of dairy cows fed diets formulated at two starch concentrations with either conventional urea or slow-release urea

This study evaluated the effects of high and moderate starch diets by substituting corn grain with wheat and rice bran in diets containing slow-release urea (SU, protected into lipids matrix microencapsulation) or conventional urea (CU) on the performance of high producing dairy cows. Twenty-four multiparous (days in milk = 83 ± 14; milk yield = 47 ± 4.5 kg/d) and sixteen primiparous (days in milk = 83 ± 12; milk yield = 37.5 ± 2.5 kg/d) Holstein dairy cows were randomly assigned to 1 of 4 treatments in a 2 × 2 factorial arrangement of treatments with 2 dietary starch concentrations [moderate starch (MS; 260 g/kg of dry matter, DM) vs. high starch (HS; 320 g/kg of DM)] and two sources of urea (SU vs. CU). The experiment lasted 52 days (d), consisting of 10 d for covariate period, 21 d for adaptation, and 21 d for sampling. In a preliminary in vitro gas test, the gas production was higher for SU than CU at 0.5, 1, 2, 6, and 24 h post-incubation (P < 0.01). There were interactions between urea source and starch level for dry matter intake (DMI, P < 0.01), propionate proportion (P = 0.04), milk urea nitrogen (MUN, P = 0.09) and rumen NH3-N (P = 0.07) concentrations; the DMI (P = 0.01) was higher and propionate proportion (P = 0.05), MUN (tendency, P = 0.08) and rumen NH3-N (tendency, P = 0.06) were lower with high than moderate starch level in CU diet, but it was not different between the two starch levels in SU diet. Furthermore, the urea source and starch level interaction was significant for butyrate proportion (P = 0.04); the butyrate proportion (P = 0.03) was lower with high than moderate starch level in SU diet, but it was not different between the two starch levels in CU diet. Cows fed CU had greater milk fat (P < 0.01) and protein (P = 0.04) yield and milk fat content (P = 0.05) and tended to have a greater 35 g/kg fat corrected milk yield (P = 0.09) than cows fed SU. The total volatile fatty acids concentrations (P = 0.04) and milk protein content (P < 0.01) were greater in HS-fed cows than in MS-fed cows. Blood urea nitrogen concentration was higher at 2 (P = 0.02) and 4 (P = 0.03) h after feeding in CU-fed cows than in SU-fed cows. Apparent digestibility of starch was greater in HS-fed cows than in MS-fed cows (P < 0.01) and in CU-supplemented cows than in those who received SU (P = 0.05). Overall, the SU product used in this study reduced the rate of ruminal nitrogen release compared to CU; however, no advantages are observed with the addition of SU when compared with CU on high-production dairy cow performance. Moreover, the results suggest that the performance of high-producing dairy cows can be maintained when wheat and rice bran are used instead of corn grains at 150 g/kg of DM.

Inadequate Hepatic Biotransformation of Choline to Phospholipids Contributes to Lipid Disorders in Early Lactation of Contemporary Holstein Cows

ObjectivesContemporary Holsteins (CH) producing more milk than unselected Holsteins (UH), but they are also more susceptible to lipid disorders, especially hepatic steatosis in early lactation. The objective of this study is to investigate the metabolic events underlying the susceptibility of genetically selected cows to lipid disorders.MethodsSerum and liver samples from periparturient CH and UH cows (n = 12/genotype) were examined by biochemical, metabolomics, and transcriptomic analyses. Serum samples were collected weekly from −5 to + 10 weeks of lactation, and the liver samples were collected on day −14, +3, +14, and + 42 of lactation. Data were analyzed by two-way ANOVA with genotype and time as two factors.ResultsThe postpartum increases of blood serum non-esterified fatty acids (NEFAs) was greater in CH cow. Serum triacylglycerols (TAGs) concentration remained comparable to those of the UH cows but the postpartum accumulation of hepatic TAG was greater in CH than in UH cows. This imbalanced lipidome in CH cows was further reflected by a greater decrease of hepatic phosphatidylcholines (PCs), which are responsible for packaging TAGs into the very-low-density lipoproteins (VLDLs). Hepatic choline content did not differ between UH and CH cows, but less phosphocholine and glycerophosphocholine were present in the liver of CH cows. Transcriptomic analysis indicated that, in the CH cows, the expression of CPT and CEPT genes in the CDP-choline pathway, the major PC biosynthesis pathway, were decreased, while the expression of BHMT and PEMT genes in the minor PC biosynthesis pathway, were increased in early lactation.ConclusionsInadequate hepatic biotransformation of choline to phospholipids contributes to PC deficiency and hepatic steatosis in the CH cow. Efforts to elevate PC synthesis could enhance hepatic VLDL export, reduce hepatic steatosis, and improve metabolic health of high-producing dairy cows in early lactation.Funding SourcesUSDA grant.