Parity Cows Research Articles

Comparative prevalence assessment of subclinical mastitis in two crossbred dairy cow herds using the California mastitis test

The study was conducted on two herds of Jersey crossbred dairy cows. Samples were taken from two dairy farms to conduct the California Mastitis Test (CMT) during milking. A total of 115 animals were sampled, with 65 animals from Farm 1 and 60 animals from Farm 2. Milk samples were collected from all four quarters of each cow. The study analyzed a total of 460 quarters from the collected milk samples. Among these quarters, 132 quarters (28.69%) were found to be infected. The prevalence of mastitis was 45% in Herd 1 and 25% in Herd 2. The study found that only one quarter of the udder was more affected in both herds. The CMT score (likely a measure of mastitis severity) increased during late lactation. Infected cows had an average milk yield/day of 3.6 liters. Inflammatory (within or under the mammary gland) infections were more common in the first and second parity cows (cows that had given birth to one or two calves, respectively). This could be ascribed to the fact that dairy cows in their starting lactations are more vulnerable to the environmental pathogens because they might not have built up their immunity yet. Overall, this study provides insights into the prevalence, severity, and patterns of mastitis in Jersey crossbred dairy cows located at two different farms. The study highlights factors such as the stage of lactation, parity, and herd differences that can influence the occurrence and severity of mastitis in these animals.

Effects of supplementing rumen-protected arginine on performance of transition cows

An experiment was conducted to determine the effects of supplementing rumen-protected arginine (RPA) on productive performance in dairy cows. One-hundred and 2 cows were blocked by parity and then by energy-corrected milk (ECM) yield. Within block, cows were randomly assigned to control (CON) that received 200 g/d of a mixture of hydrogenated soybean oil and heat-treated soybean meal to supply 30 g of metabolizable protein (MP), or 200 g/d of a product containing 30 g of metabolizable arginine (RPA), which increased the dietary arginine from 5.7 to 7.5% of the MP from 250 d of gestation to 21 d postpartum. After 21 d postpartum, cows were fed the same diet and data were collected until 84 d postpartum. Cows fed RPA produced an additional 2.5 kg of colostrum (5.3 vs. 7.8 ± 1.0 kg) and 220 g more immunoglobulin G (526 vs. 746 ± 93 g) than CON cows. Supplementing RPA increased the yields of milk (32.8 vs. 34.9 ± 1.0 kg/d), ECM (37.8 vs. 40.9 ± 1.2 kg/d), and milk total solids (4.48 vs. 4.86 ± 0.14 kg/d) in the first 21 DIM. The benefits of RPA extended beyond the period of supplementation, with a 6.4% increase in yield of ECM per kg of dry matter consumed in all cows (1.88 vs. 2.00 ± 0.05 kg/kg) and an increase in ECM yield, but only in parous cows (44.2 vs. 48.5 ± 1.5 kg/d). Feeding RPA increased the concentrations of urea N in plasma pre- (12.5 vs. 13.9 ± 0.4 mg/dL) and postpartum (11.6 vs. 13.2 ± 0.4 mg/dL), and in milk during the first 21 d postpartum (11.0 vs. 12.0 ± 0.3 mg/dL). Treatment did not affect the concentrations of AA in plasma prepartum, but feeding RPA tended to increase citrulline (72.5 vs. 77.5 ± 2.7 μM), whereas RPA either tended to decrease isoleucine (129.5 vs. 120.9 ± 5.7 μM) or decreased the concentrations of leucine (181.3 vs. 170.2 ± 6.4 μM) and valine (293.2 vs. 276.7 ± 10.4 μM) postpartum. Feeding RPA increased the relative expression of transcripts involved in AA transport (SLC38A4), urea cycle (ARG1), and gluconeogenesis (PC, PEPCK, and G6PC) in hepatic tissue. Feeding diets to supply additional arginine as RPA during the transition period benefited productive performance in dairy cows that extended beyond the period of supplementation despite minor changes in plasma AA concentrations.

PSVII-14 Influence of dam parity and weaning strategy in previous lactation on feedlot performance of Nellore steers

Abstract In tropical beef cattle production systems, the impact of seasonality may be particularly challenging for young cows (primiparous or secondiparous) due to their increased nutritional requirements, encompassing maintenance, growth, gestation, and, in the case of secondiparous cows, lactation. Literature indicates that extending the duration of lactation during gestation is associated with decreased performance of progeny in their postnatal life. Therefore, implementing an early weaning approach can be an effective strategy to alleviate the nutritional demands of lactation in dams, thereby allocating more nutrients for fetal growth. This study aimed to evaluate the effect of early weaning on the feedlot performance of progeny that were in utero at the time of weaning intervention. To create experimental units, secondiparous and multiparous Nellore cows were assigned to one of two weaning strategies, where suckling calves were either; 1) early weaned 150 d (EW); or 2) conventional weaned at 240 d (CW). All calves were weaned at 150 d of lactation in 2022. Three bulls were used: Bull 1: had 13 calves with multiparous cows, had 7 calves with secondiparous cows, comprising 11 EW and 9 CW; Bull 2: had 10 calves with multiparous cows, had 6 calves with secondiparous cows, comprising 6 EW and 10 CW; and Bull 3: had 7 calves with multiparous cows, had 15 calves with secondiparous cows, comprising 11 EW and 11 CW. All cows were managed similarly after weaning, and through parturition, and weaning of subsequent calf, with resulting calves used for the current experiment. Nellore bulls (n = 57) with an initial body weight (BW) of 417.23 ± 9.12 kg and 18 mo of age were allocated to feedlot pens (equipped with Intergado equipment) and fed a common total mixed ration (80:20; concentrate:corn silage) for 97 ± 1.60 d. Bulls were distributed in a randomized complete block in a 2 × 2 factorial arrangement, considering dam weaning strategy in the previous lactation (EW and CW) and dam parity at subsequent calving (multiparous or secondiparous cows, MC and SC, respectively). Data were analyzed using PROC MIXED of SAS 9.4, with a model including the effects of dam weaning strategy, dam parity, and their interaction. Data were considered significant when P values were less than 0.05 and indicated a trend when 0.05 < P ≤ 0.10. There was an interaction between weaning strategy and cow parity, with calves born to SC-CW having reduced initial (P = 0.04) and final BW (P = 0.01) compared with all other groups (Figure 1 and 2). Steers from MC had greater dry matter intake (P = 0.003), and greater biological efficiency (P = 0.03; Table 1). Early weaning improved the final BW of steers born to secondiparous cows, suggesting it could be a strategy to enhance the performance of offspring and the reproductive performance of both secondiparous and multiparous cows.

261 Vitamin A administration in pregnant cows or newborn calves: Growth performance and carcass traits

Abstract This study aimed to evaluate the effects of Vitamin A (VA) injection on the growth performance and carcass traits of Nellore × Angus crossbred steers and heifers. For that, the same sire inseminated Nellore cows from two artificial insemination (AI) groups were randomly assigned to one of three treatments at 250 d of gestation: no VA injection (Control); VA injection in pregnant cows at 250 d of gestation (VAcow; 2,000,000 IU single dose); VA injection in newborn calves at birth and 60 d of age (VAcalf; 200,000 IU each dose). Cow-calf pairs were kept in the same paddock, and calves received creep-feeding supplementation from 90 d of age to weaning. After weaning, steers and heifers [n = 36; body weight (BW) 213 ± 25.7 kg] were stratified by treatment and BW and allotted into 16 pens. After 207 d of feeding (77 d of growing diet + 130 d of finishing diet), steers and heifers were slaughtered at a commercial abattoir. Data were analyzed using the MIXED procedure of SAS 9.4 with fixed effects of VA injection, sex, and VA injection*sex interaction. The random effects were animal, AI group, and cow parity. Average daily gain before weaning (P < 0.01) and final BW in the finishing phase were greater (P = 0.04) in VAcow steers compared with heifers from all treatments (Table 1). Vitamin A had a positive impact on weaning BW of male calves and a negative impact on heifers (P < 0.01). There was no treatment difference (P = 0.35) in feedlot average daily gain (ADG), but steers had greater (P = 0.03) ADG compared with heifers. Moreover, VAcow steers had greater dry matter intake (DMI) in the feedlot (P = 0.04) compared with other treatments, and there was no effect of VA on DMI of heifers. On the other hand, feedlot feed efficiency tended to be greater (P = 0.07) in Control steers compared with other treatments, with no VA effect on heifers too. The ribeye area was greater (P = 0.04) in VAcow steers than in Control steers and heifers from all treatments. Intramuscular fat content was greater (P = 0.04) in VAcow steers than in Control and VAcalf steers. However, there was no effect of VA on heifers and VAcow steers. In addition, VAcow treatment tended (P = 0.08) to increase backfat thickness. In conclusion, VA injection in pregnant cows can be a strategy to improve marbling in steers, but there is no effect on intramuscular fat in heifers. Additionally, VA injection in pregnant cows produced intramuscular content in beef of steers, similar to heifers.

10 Awardee Talk: Pregnancy losses in Bos indicus-influenced cowherds

Abstract Pregnancy loss is recognized as a major reproductive challenge in beef cattle operations. Most pregnancy losses are associated with early embryonic mortality, but limited research evaluated pregnancy losses throughout the gestation period. Research is warranted to address this gap in knowledge, particularly fetal losses in Bos indicus-influenced females. This subspecies predominates in tropical regions of the planet, which contain more than 80% of the world’s cattle population and supply a major portion of the global demand for beef products. Our group recently evaluated pregnancy losses from d 30 of gestation to calving in 4,926 Nelore females assigned to an ovulation synchronization + fixed-time artificial insemination (FTAI) protocol. Pregnancy loss was greater (P < 0.01) from d 60 to 150 of gestation (10.2%) compared with d 30 to 60 of gestation (6.0%) and with d 150 of gestation to calving (7.4%) and differed (P = 0.04) between these latter two periods. Pregnancy loss from d 30 to 60 of gestation did not differ (P = 0.26) among cow parities (nulliparous, primiparous, and multiparous), whereas total pregnancy losses (d 30 to calving) were greater (P < 0.01) in precocious (28.4%) and conventional (27.1%) heifers compared with primiparous (16.4%) and multiparous (13.0%) cows. In a second experiment, pregnancy losses from fixed-time embryo transfer (FTET) to calving were evaluated in 4,366 FTET events using Nelore × Angus recipient heifers. Pregnancy losses were greater (P < 0.01) from FTET to d 32 of gestation compared with d 32 to 100 and with d 100 to calving (58.7, 39.5, and 36.7%, respectively), and did not differ (P = 0.56) between these latter periods. Recipients that lost the pregnancy from FTET to d 32 gained less (P < 0.01) body condition score after FTET compared with recipients that maintained the pregnancy. Pregnancy losses from d 32 to calving were greater (P < 0.01) in recipients reared in drylots and moved to pastures on d 32 compared with recipients reared on pasture. Collectively, these results provide novel information about pregnancy losses in Bos indicus females, with a substantial proportion of losses occurring as fetal mortality.

Social interactions of dairy cows and their association with milk yield and somatic cell count

The social environment experienced by livestock can have implications for their health, welfare, and subsequently, their productivity. Changes in the dairy industry have led to larger herd sizes and altered management of cows, which has impacted their social environment. Studies have shown that mixing of animals can lead to social instability of groups and expansion of herds can lead to high stocking densities resulting in social stress and negative effects on production. Yet few studies have assessed the putative impact of positive cow-cow interactions, such as proximity to preferred herd mates and engaging in grooming, on milk production and udder health. To address this, we used cattle proximity as a proxy for affiliative interactions between cows in three dairy herds in south-west England over one week study periods. We created proximity networks of dairy cows and measured cow-cow associations according to milk yield, somatic cell count (SCC; an indicator of mastitis), parity (number of lactations in the cow’s lifetime), and lactation stage (grouped by days in milk for current lactation). We then assessed associations between social factors and production and health measures (milk yield and SCC). In all three herds, cows interacted more with cows in the same parity, suggesting early social bonding may be evident later in life and that grouping animals in terms of parity might encourage affiliative interactions. Cows did not associate according to milk yield, SCC, or lactation stage. There was no significant association between milk production or SCC and the total time spent in social contact with other cows, the mean time spent with the four closest herd mates, or the number of closest herd mates of the same parity. We suggest that further research on positive social environments for dairy cattle is warranted in the interests of improving welfare and enabling a more robust assessment of the putative effects on production and health parameters

Milk component ratios and their associations with energy balance indicators and serum calcium concentration in early-lactation spring-calving pasture-based dairy cows

Indirect assessment of metabolic status using milk samples provides a non-invasive and objective tool for cow-level health monitoring. Milk fat-to-protein ratio (FPR) has been commonly evaluated as an indirect measure for negative energy balance (EB) in confined dairy cows. However, milk component ratios have not been explored for their association with pasture-based cows' metabolic status. The objectives of this observational study were to 1) describe milk component ratios from 0 to 45 d postpartum, 2) evaluate the associations between milk component ratios [FPR, fat-to-lactose (FLR), protein-to-lactose (PLR)] and indicators of EB (serum β-hydroxybutyrate (BHB) concentration at 5-45 d postpartum and body condition score (BCS) change during the transition period), and 3) evaluate the associations between milk component ratios and serum Ca concentration 0-4 d postpartum in spring-calving dairy cows from pasture-based commercial farms. Milk component ratios were determined on samples collected before AM or PM milkings from 548 cows at 0-45 d postpartum (n = 970). Serum BHB and Ca determinations were performed in blood samples collected at the time of milk sample collection at 5-45 d postpartum (n = 918) and 0-4 d postpartum (n = 50), respectively; and BCS change was calculated using BCS assigned between 29 d prepartum and 45 d postpartum (n = 851). Cows' calving date, parity (1st, 2nd-3rd or ≥ 4th) and breed (Holstein-Friesian or dairy crossbred) information was obtained from the farm records. Data was analyzed by multiple linear regression. Average milk FPR, FLR and PLR were 0.70, 0.53 and 0.72, respectively. Milk FPR linearly increased while milk FLR linearly decreased postpartum both at a rate of 0.004 units per day; milk PLR decreased 0.05 units per day for the first 30 d postpartum and moderately increased afterward. Milk FPR and FLR were 0.71 and 0.52 units lower before AM than PM milking, respectively; while milk PLR was similar before AM and PM milking. Milk FPR and FLR were 0.07 to 0.10 units higher for 2nd-3rd compared with 1st and ≥ 4th parity cows. Milk PLR was 0.03 units greater for ≥ 4th compared with 2nd-3rd and 1st parity cows. Further, crossbred cows had 0.07, 0.08 and 0.03 higher milk FPR, FLR and PLR than Holstein-Friesian cows, respectively. Moderate to high P-values along with moderate to small estimated slopes and wide 95% confidence intervals were observed for the associations between milk component ratios and indicators of EB. A positive linear association was observed between milk FPR and serum Ca concentration within 4 d postpartum; milk FPR increased 0.31 units per each mmol/L increase in serum Ca concentration. Cows with low serum Ca concentration within 4 d postpartum had 0.27 units lower milk FPR compared with cows at or above the threshold (2.12 mmol/L), and tended to have 0.15 units lower milk FPR compared with cows at or above the threshold (2.00 mmol/L). In conclusion, further research is needed to reach conclusions on the association between milk component ratios determined before milking and EB indicators. The potential of milk FPR for monitoring blood Ca status warrants further investigation in early-lactation pasture-based dairy cows.

Prepartum anti-inflammatory therapies in Holstein dairy cows blocked by parity and body condition score group: Effects on metabolic stress, systemic inflammation, performance, and health

The objective of this study was to assess the effects of prepartum administration of anti-inflammatory therapies on body condition score (BCS), β-hydroxybutyrate (BHB) concentration, haptoglobin (HP) concentration, milk yield, milk components, rumination time, clinical health events and reproductive performance in Holstein dairy cows. At 14 d before the expected calving date, cows (PAR; n = 170) and heifers (nulliparous [NUL]; n = 63) were blocked by BCS group (optimal = 3-3.5 [OPT]; over-conditioned cows [OVERC; BCS ≥ 3.75 pts.]) and parity (NUL; PAR) and randomly allocated to one of 3 treatment groups: 1) ASA (n = 78): receive one oral administration of acetylsalicylic acid (4 boluses; 480 grain/bolus); 2) MEL (n = 76): receive one oral administration with meloxicam (1mg/kg of BW), or 3) PLC (n = 77): receive one oral treatment with gelatin capsules filled with water. Body condition score was assessed, and blood samples were collected, weekly starting one week before treatment until 3 weeks after calving. Daily milk yields and daily rumination times were collected from on-farm computer records. Dairy Herd Improvement Association (DHIA) monthly test data were collected to assess milk yield, somatic cell counts, and milk components. Furthermore, health events, culling rate, and reproductive performance data were collected from on-farm computer records. The data were analyzed using MIXED, GLIMMIX, and LIFETEST procedures of SAS as a randomized complete block design. On average, MEL-NUL cows produced 4.77 ± 0.93 kg/d and 4.81 ± 0.92 kg/d more milk from wk 6 to wk 21 of lactation compared with ASA-NUL and PLC-NUL cows, respectively. Similarly, there was a week by treatment by body condition group interaction (P = 0.01), where OVERC cows treated with MEL produced more milk from wk 10 to wk 15 of lactation compared with ASA- OVERC and PLC-OVERC cows. Parous cows treated with ASA had lower BCS compared with PAR cows treated with MEL or PLC. A lower percentage of OVERC cows treated with ASA became sick in the first 60 DIM compared with MEL- OVERC and PLC- OVERC cows (ASA = 23.88 ± 7.26%, MEL = 46.36 ± 8.57%; PLC = 46.74 ± 8.53%; P = 0.04). Parous cows treated with ASA had (P = 0.03) a higher hazard ratio to become pregnant by 300 DIM compared with PAR MEL cows. Although the study was not sized for finding treatment differences in blocking criteria groups, these results suggest that treatment with prepartum anti-inflammatory therapies may have positive effects on milk yield and postpartum health in specific groups of cows, such as NUL and OVERC cows, while it may not be recommended for other animal categories, such as parous cows and cows with optimal BCS. Larger studies are needed to strengthen the associations observed in this study.

Effects of Early Lactation Milking Frequency in an Automated Milking System on Cow Performance.

Automated milking systems (AMS) are increasingly adopted for dairy cow production, promoting individualized cow management dependent on factors like lactation stage, age, and productivity. The study objective was to investigate the effects of early lactation milking frequency on cows milked via AMS. Multiparous Holstein cows blocked by parity and due date were randomly assigned to treatments (n = 8 per treatment): three (3X) or six (6X) milkings per day (MPD). The experimental phase (EXP) was defined as 4 to 29 days in milk (DIM). The AMS settings were programed so 3X cows were limited to three MPD while 6X cows were allowed six MPD. Afterwards was the carry over phase (CO) ranging from 30 to 90 DIM; all cows were allowed up to six MPD. Measurements by the AMS included bodyweight, milk yield (MY), and pellet intake. Weekly composite milk samples were analyzed for macronutrient composition and fatty acid (FA) profile. Coccygeal blood was sampled at 3, 8 ± 1, and 13 ± 1 DIM; concentrations of blood plasma analytes were quantified. Greater MPD was achieved for 6X cows versus 3X cows during EXP, but similar during the CO. Daily MY was non-separable during the EXP while 6X cows in their third or greater lactation group (3 + LG) had greater MY than 3X cows of the same LG during the CO. Milk fat content and 4% fat-corrected MY were both greater for 6X, 3 + LG cows during the EXP compared to 3X, 3 + LG cows. Milk FA methyl esters (FAME) proportions were different between MPD groups, with 6X, 3 + LG cows having the lowest short, even-chain FA from de novo or post-absorptive origin. Differences in analytes indicated that 6X, 3 + LG cows experienced metabolic stress and incorporated greater FA from adipose tissue. Greater early lactation MPD in AMS may shift cow nutrient partitioning to support greater production in 3+ parity cows.

Estimations of prepartum feed intake and its effects on transition metabolism and subsequent milk production

The objectives of this study were to identify factors associated with prepartum DMI, evaluate the performance of linear models to estimate prepartum DMI using different classes of predictors, and investigate the consequences of different levels of prepartum DMI on transition metabolism and lactation performance. Individual feed intake of nulliparous (n = 100) and parous cows (n = 173) was measured by automatic feeding bins from d -35 to 98 relative to calving. Rumination and physical activities were monitored by wearable sensors. Blood metabolites were measured on d -21, -10, -3, 0, 3, 7, 10, 14, and 21. Body weight (BW) and body condition score (BCS) were assessed throughout the study. The average prepartum DMI as percentage of BW (DMIpBW) was calculated for each cow and used as dependent variable of linear models. Parity, prepartum BCS and BW, milk production in the previous lactation (M305) and at dry-off (MYDO), and length of the dry period were associated with DMIpBW and explained 41% of the variation in all cows, and 49% in parous cows. Estimations of DMIpBW were improved when data on prepartum rumination and blood metabolites were added in the predictive models. In the latter, the adjusted R-Sq increased to values between 47 and 61%, and selected models performed consistently in a 5-fold cross-validation analysis. To evaluate the implications of DMIpBW to transition metabolism and performance, cows were ranked within parity and classified into terciles as low (LFI), moderate (MFI), or high feed intake (HFI). The mean DMI was 1.44, 1.70, and 1.91 ± 0.01% of BW, respectively. No differences in BW were observed in nulliparous cows, but all 3 groups of parous cows differed (LFI = 892, MFI = 849, HFI = 798 ± 8 kg). The proportion of cows with BCS > 3.5 at enrollment differed among all groups, and averaged 67.4, 55.1, and 36.5 ± 6%, respectively. For parous cows, M305 and MYDO differed among all groups and averaged 9,808, 10,457, and 11,182 ± 233 kg, and 18.1, 23.1, and 26.2 ± 1 kg/d, respectively. After calving, DMI (LFI = 20.9, MFI = 21.9, and HFI = 22.1 ± 0.2 kg/d) and milk yield (LFI = 36.7, MFI = 38.2, and HFI = 38.3 ± 0.4 kg/d) was lower in LFI cows compared with the other 2 groups. Postpartum EBAL differed among all groups and averaged -2.79, -1.63, and -0.66 ± 0.3 Mcal/d for LFI, MFI, and HFI, respectively. During the transition period, LFI cows had higher serum concentrations of NEFA, BHB, Cl (prepartum only), and AST (postpartum only), and lower serum concentrations of cholesterol, P, GLDH, GGT (prepartum only), AST (prepartum only), urea (parous only), and SOD activity (parous only). In conclusion, a low level of prepartum DMI was associated with fatter and heavier cows, lower milk production in previous lactation, important adjustments in energy metabolism, and moderate losses in DMI and milk yield in the subsequent lactation. Moreover, the inclusion of prepartum rumination activity and target blood metabolites into predictive models improved the estimations of prepartum DMI.

Magnitude of change in prepartum feed intake: Estimations using multiple classes of predictors and associations with transition metabolism, health, and milk production

The objectives of this study were to identify factors associated with the relative change in prepartum DMI (RCDMI) of 273 cows fed individually, evaluate the performance of linear models to estimate RCDMI using different classes of predictors, and characterize the implications of RCDMI to transition metabolism, health, and subsequent milk production. Two periods of interest were established. Period 1 comprised d -21 to -12 relative to calving, when DMI was stable. Period 2 comprised d -4 to -1, when average DMI was distinctly declined. The RCDMI from period 1 to 2 was calculated as a percentage value, which ranged from -75% to 15% and averaged -18.1% (± 15.0%). Season, parity, body fatness, body weight, milk production in the previous lactation and at dry-off, and length of dry period were associated with RCDMI and explained 11% of the variation in all cows, and 19% when only parous cows were considered. Performance of linear models to predict RCDMI was improved when data on rumination and physical activities and target blood metabolites were added. The adjusted R2 increased to values between 0.45 and 0.55, and selected models performed consistently in cross-validation analyses. To evaluate the implications of RCDMI, cows were ranked within parity according to RCDMI and classified into terciles as large decline (LDec), moderate decline (MDec), or small decline (SDec). By design, DMI did not differ between tercile groups in period 1 (13.3 ± 0.2 kg/d), but differed substantially in period 2 (LDec = 8.8; MDec = 11.2; SDec = 12.7 ± 0.2 kg/d), creating important differences in RCDMI among groups (LDec = -33.8; MDec = -16.2; SDec = -3.4% ± 0.8%). At enrollment, cows in the LDec and MDec groups were heavier (LDec = 788; MDec = 775; SDec = 750 ± 7 kg), and the proportion of cows with BCS >3.5 was higher in LDec (LDec = 63%; MDec = 47%; SDec = 38%). An interaction between group and time was observed for postpartum DMI, which started lower in LDec than in SDec cows, equaled by the end of transition, and inverted at wk 13 and 14 after calving. Yields of ECM were greater in LDec than in SDec cows, and both groups did not differ from MDec (LDec = 41.0; MDec = 40.3; SDec = 39.0 ± 0.5 kg/d). The LDec cows had decreased energy balance and greater concentrations of nonesterified fatty acids, β-hydroxybutyrate, and aspartate aminotransferase in serum, and greater glutathione peroxidase activity in plasma than SDec cows. Larger declines in prepartum DMI were also associated with increased risk for postpartum disease, although the associations were only weak to moderate. In conclusion, a large decline in prepartum DMI of cows fed ad libitum was associated with important adjustments in the energy metabolism and antioxidants activities, and greater milk production in the subsequent lactation. These findings indicate that feed intake decline close to parturition is likely a normal response to physiological adaptations at the onset of lactation when cows are fed ad libitum.

The prevalence and factors associated with mastitis in dairy cows kept by small-scale farmers in Dodoma, Tanzania

Bovine mastitis is among the major diseases of economic importance in the dairy industry worldwide. Hygienic conditions during milking and housing are important determinants of mastitis infections. However, arid and semi-arid areas have a scarcity of water, which is an essential component of cleanliness. Thus, the study determined the prevalence of mastitis and associated factors in Dodoma, a semi-arid region in Tanzania. Three hundred and sixty-eight lactating cows were selected randomly from 114 farms in the Dodoma urban district for mastitis determination based on clinical signs and the California Mastitis Test. About 59.8 % of the cows had mastitis, and the subclinical type dominated. Factors associated with mastitis prevalence were cleanliness (hand and udder washing before milking), farmers' awareness of mastitis, the cow's parity and lactation stage, and herd size. Milk yield was not associated with the mastitis status of the cow but was related to the breed of the cow, whether warm or cold water was used to wash the cow's udder, parity, and lactation stage. Improvement in education on the importance of hygiene is necessary, as 38.6 % of the farmers were unaware of mastitis. Further detailed studies on microbiology, such as bacteriologic culture and polymerase chain reaction, are recommended to formulate interventions.

The Correlation of Heat Tolerance Coefficient (HTC) and Temperature Humidity Index (THI) with Milk Production of Dairy Cows in Bangun Lestari Farm, Tulungagung

Determining the relationship between environmental adaptability and milk production across various parities using HTC and THI values was the aim of this study. Purposive sampling was employed to choose thirty dairy cows of parity 1 and 2, for the study. For this investigation, a case study was employed. The temperatures and humidity of the barn environment were used to measure the THI value, which was determined by the HTC value, the milk production of mothers with varying parities, and the rectal temperature and respiratory frequency. Research results demonstrated a negative connection between the two independent variables—the THI and HTC values—and milk production at parities 1 and 2. This suggests that either environmental stressors or higher HTC or THI values resulted in lower milk production. At parity 1, there was a poor correlation, and at parity 2, a moderate correlation between the HTC value and milk production. The correlation coefficients for parity 1 and parity 2 were, respectively, r = 0.410, R2 = 0.168, and r = 0.370, R2 = 0.137. There was just a slight association observed between the THI value and milk production at parities 1 and 2. The correlation coefficient for parity 1 was (r = 0.220; R2 = 0.049), but the correlation coefficient for parity 2 was (r = 0.227; R2 = 0.51). According to the study's findings, milk production in parities 1 and 2 is only marginally correlated with HTC and THI values.

Correlation of Body Condition Score and Parity in Dairy Cows that Experienced Repeated Breeding in Sendang, Tulungagung

Repeat breeding is a syndrome which affected the reproduction and production efficacy of dairy cattle. Dairy cow is one of an animals which produce milk. This syndrome may cause high economic losses in dairy cattle farm. This research was conducted from February to March 2023. The aim of this research was to determine the correlation of body condition score and parity of repeat breeding on the dairy cow at Tani Wilis Cooperation, Sendang, Tulungagung. A total of 46 dairy cows that contributed to the repeat breeding were used in this study. Sampling was done by purposive sampling with the following condition the date AI and the date of parturition. This research was conducted in a survei with primary and secondary data collection. Primary data retrieval is done by interviewing farmers, body condition score of each dairy cow, and direct observation. As for the secondary data obtained by recording the card Artificial Insemination (AI) owned by inseminator. Data were analyzed using correlate statistics followed by Spearmann Test. The result of the research indicated that no significant difference (P>0,05) in body condition score and parity.

Effect of carbohydrate type in silages and concentrates on feed intake, enteric methane, and milk yield from dairy cows

Dietary carbohydrate manipulation can be used to reduce enteric CH4 emission, but there is a lack of studies on the interaction of different types of carbohydrates that can affect feed intake and ruminal fermentation. Understanding this interaction is necessary to make the most out of CH4 mitigation feeding strategies using different dietary carbohydrates. The aim of this study was to test the effect on enteric CH4 emission, feed intake and milk production response when cows were fed either grass-clover (GCS) or corn silage (CS) as the sole forage source (55% of dry matter, DM), in combination with either barley (BAR) or dried beet pulp (DBP) as a concentrate (21.5% of DM). Twenty-four (half first and half second parity) cows were used in a crossover design with 2 periods of 21 d each, receiving 2 of 4 diets obtained from a 2 × 2 factorial arrangement of the experimental diet. Feed intake, CH4 emission metrics and milk production were recorded at the end of the experimental periods. The diets had NDF concentrations between 258 and 340 g/kg of DM, and starch concentrations between 340 and 7.45 g/kg of DM (CS-BAR and GCS-DBP, respectively). The effects of silage and concentrate on dry matter intake (DMI) were additive, with the highest feed intake in cows fed COR-BAR, followed by cows fed COR-DBP, GCS-BAR, and GCS-DBP (21.2, 19.9, 19.1, and 18.3 kg/d). Energy corrected milk (ECM) yield was not affected by silage source in first parity cows, but it was higher for cows fed CS than cows fed GCS in second parity. The effects of silage and concentrate on CH4 production (g/d), yield (g/kg of DMI) and intensity (g/kg of ECM) were not additive as cows fed GCS had similar responses regardless of the concentrate used, but cows fed CS had lower CH4 production, yield and intensity, when fed BAR instead of DBP. The lower CH4 production, yield and intensity in cows fed CS-BAR compared with other diets could be partially explained by the nonlinear relationship between ruminal VFA and carbohydrates (NDF and starch) concentration reported in literature, however, we observed a linear relationship between acetate:propionate ratio and CH4 yield, suggesting possible other effects. The effects of silage and concentrate on the ruminal VFA were additive in first parity cows, but not in second parity cows. The interaction between dietary CHO type and parity might indicate an effect of feed intake or the energy balance of the cow. Feeding cows silage and concentrate both rich in starch can result in the lowest enteric CH4 emission.

Effect of oxytocin use during colostrum harvest and the association of cow characteristics with colostrum yield and immunoglobulin G concentration in Holstein dairy cows

Our objectives were to determine the effect of oxytocin use during colostrum harvest on colostrum yield and IgG concentration in Holstein dairy cows on a commercial dairy in New York and to describe associations of cow characteristics with these outcomes. Animals were enrolled between July and October 2023 using a randomized block design, with day of enrollment as the unit of randomization. A median (range) of 10 (3-19) cows were enrolled per day. Treatments were (1) 40 IU oxytocin (OXY40), (2) 20 IU oxytocin (OXY20), and (3) an untreated control group (CNTR). Oxytocin was administered i.m. ∼45 s before unit attachment in a rotary parlor. Colostrum weight was measured using the colostrum bucket-embedded scale or a platform scale when the yield was less than the smallest bucket scale. The concentration of IgG ([IgG]) in colostrum was determined using radial immunodiffusion and used to calculate total IgG, and DM (%) was determined by oven drying. Individual cow characteristics such as parity, calf sex, weight, dystocia score, stillbirth, and milk production in wk 4 of lactation; additionally, for multiparous cows, dry period length and previous lactation dry-off linear SCS were collected. Data were analyzed separately for primiparous and multiparous cows using backward stepwise elimination. To produce final mixed effects ANOVA models, primiparous cows (n = 201) were randomized to 35.8% (n = 72) OXY40, 32.8% (n = 66) OXY20, and 31.3% (n = 63) CNTR. Multiparous groups (n = 435) were randomized to 34.7% (n = 151) OXY40, 29.7% (n = 129) OXY20, and 35.6% (n = 155) CNTR. The median (range) colostrum yield was 6.0 (0-20.6) kg and [IgG] was 98.5 (0.1-293.6) g/L in the study population. In primiparous cows, OXY40 had a higher colostrum yield (LSM [95% CI]) of 5.4 (4.9-5.9) kg compared with both OXY20 (4.1 [3.5-4.7] kg) and CNTR (3.8 [3.3-4.3] kg). In multiparous cows, OXY40, OXY20, and CNTR did not differ in colostrum yield (5.9 [5.3-6.5], 5.7 [5.1-6.3], and 5.4 [4.8-6.0] kg, respectively), but colostrum yield was greater in parity 2 compared with all other parities, cows giving birth to male calves, cows with the highest milk production at wk 4 of lactation, and cows with a dry period of >65 d. Oxytocin use did not affect [IgG] in either primiparous or multiparous cows, but [IgG] was highest in cows in parity ≥4 and lowest in cows dry >65 d. In summary, oxytocin use at 40 IU i.m. was associated with a higher colostrum yield in primiparous cows only and no change in [IgG]. Oxytocin use likely addressed disturbed milk ejection and therefore increased colostrum yield in heifers milked for the first time in a rotary parlor. This study confirms cow characteristics associated with colostrum production within a single herd.

Comparison of 3 mathematical models to estimate lactation performance in dairy cows

Milk yield dynamics and production performance reflect how dairy cows cope with their environment. To optimize farm management, time series of individual cow milk yield have been studied in the context of precision livestock farming, and many mathematical models have been proposed to translate raw data into useful information for the stakeholders of the dairy chain. To gain better insights on the topic, this study aimed at comparing 3 recent methods that allow one to estimate individual cow potential lactation performance, using daily data recorded by the automatic milking systems of 14 dairy farms (7 Holstein, 7 Italian Simmental) from Belgium, the Netherlands, and Italy. An iterative Wood model (IW), a perturbed lactation model (PLM), and a quantile regression (QR) were compared in terms of estimated total unperturbed (i.e., expected) milk production and estimated total milk loss (relative to unperturbed yield). The IW and PLM can also be used to identify perturbations of the lactation curve and were thus compared in this regard. The outcome of this study may help a given end-user in choosing the most appropriate method according to their specific requirements. If there is a specific interest in the post-peak lactation phase, IW can be the best option. If one wants to accurately describe the perturbations of the lactation curve, PLM can be the most suitable method. If there is need for a fast and easy approach on a very large dataset, QR can be the choice. Finally, as an example of application, PLM was used to analyze the effect of cow parity, calving season, and breed on their estimated lactation performance.

Use of rumination time in health risk assessment of prepartum dairy cows

The objectives of this observational cohort study were to evaluate the associations of rumination time (RT) in the last week of pregnancy with transition cow metabolism, inflammation, health, and subsequent milk production, reproduction, and culling. Pregnant nulliparous (n = 199) and parous (n = 337) cows were enrolled 21 d before the expected calving. RT and physical activity were monitored automatically by sensors from d -21 to 15 relative to calving. Blood samples were collected on d -14, -5, 4, 8, and 12 ± 1 relative to calving. Diagnoses of clinical health problems were performed by researchers from calving to 15 d in milk (DIM). In classification 1, cows were ranked based on average daily RT in the last week of pregnancy and classified into terciles as short RT (SRT), moderate RT (MRT), or long RT (LRT) for association analyses. In classification 2, RT deviation from the parity average was used in a receiver operating characteristic curve to identify the best threshold to predict postpartum clinical disease. Cows were then classified as above the threshold (AT) or below the threshold (BT). Compared with cows with LRT, cows with SRT had greater serum concentrations of NEFA (0.47 vs 0.40 ± 0.01 mmol/L), BHB (0.58 vs 0.52 ± 0.01 mmol/L), and haptoglobin (0.22 vs 0.18 ± 0.008 g/L) throughout the transition period, and reduced concentrations of glucose, cholesterol, albumin, and magnesium in a time-dependent manner. Parous cows with SRT had higher odds of postpartum clinical disease (adjusted odds ratio [AOR]: 3.7; 95% confidence interval [CI]: 2.1-6.4), lower odds of pregnancy by 210 DIM (AOR: 0.34; CI: 0.15-0.75), and lower milk production (46.9 vs 48.6 ± 0.5 kg/d) than parous cows with LRT. Deviation in prepartum RT had good predictive value for clinical disease in parous cows (area under the curve [AUC]: 0.65; CI: 0.60-0.71) but not in nulliparous (AUC: 0.51; CI: 0.42-0.59). Separation of parous cows according to the identified threshold (≤-53 min from the parity average) resulted in differences in serum concentrations of NEFA (AT = 0.31 ± 0.006, BT = 0.38 ± 0.014 mmol/L), BHB (AT = 0.49 ± 0.008, BT = 0.53 ± 0.015 mmol/L), and globulin (AT = 32.3 ± 0.3, BT = 34.8 ± 0.5 g/L) throughout the transition period, as well as in serum cholesterol, urea, magnesium, albumin, and haptoglobin in a time-dependent manner. BT parous cows had higher odds of clinical disease (AOR: 3.7; CI: 2.1-6.4), reduced hazard of pregnancy (AHR: 0.64, CI: 0.47-0.89), greater hazard of culling (AHR: 2.1, CI: 1.2-3.6), and lower milk production (46.3 ± 0.7 vs 48.5 ± 0.3 kg/d). External validation using data from 153 parous cows from a different herd and the established threshold in RT deviation (≤-53 min) resulted in similar predictive value, with the odds of postpartum disease 2.4 times greater in BT than AT (37.5 vs 20.1%). In conclusion, RT in the wk preceding calving was a reasonable predictor of postpartum health and future milk production, reproduction, and culling in parous cows but not in nulliparous cows.

Association between production and reproduction parameters based on parity and breed of dairy cows in the Czech Republic

Abstract. Milk production and the efficiency of dairy cow breeding are significantly influenced by reproductive factors. The purpose of our research was to examine the relationships between selected milk production and reproductive parameters. We evaluated 659 dairy cows, including 444 purebreds from the Czech Fleckvieh and Holstein breeds and 215 crossbreds. Our primary objective was to assess the impacts of breed and parity on specific milk production and reproductive parameters. The study revealed significant results regarding the interaction between certain breed groups and parity. In particular, there was a noticeable increase in milk yield with parity. Furthermore, it was also evident that the highest milk yield values were related to the milk content. Breed group H, which represents cows with a more than 50 % Holstein bloodline, had the highest values of the monitored milk content. Our findings show that first-lactation crossbred Czech Fleckvieh cows had a reduced milk yield, decreased fat, and lactose content in milk. However, they had a more favourable calving interval when compared to purebred Czech Fleckvieh and higher-parity Holstein crossbreds. Crossbred H, in comparison to C100 and C50, whether purebred or crossbred with Czech Fleckvieh, showed a relatively higher content of some milk components. The results for service periods and calving intervals were not statistically significant. The findings of this study highlight the promising potential of higher-parity Holstein crossbred cows in terms of milk yield and the advantages of lower-parity ones concerning milk contents.

Exploring factors influencing machine milk yield of dairy cows in cow-calf contact systems: Cow behavior, animal characteristics, and milking management

The objective of this study was to explore factors contributing to low machine milk yield of cows with cow-calf contact. Danish Holstein dairy cows were assigned to 1 of 3 cow-calf contact treatments: full-time with the calf (n = 24), part-time with the calf between morning (a.m.) and afternoon (p.m.) milking and separated overnight (n = 23), or separated from the calf at birth (n = 23). Behavior of cows (stepping and kicking in the parlor) and milking procedures (teat or udder stimulation frequency, preparation duration) were recorded at a.m. and p.m. milking on 2 d during wk 4 and 6 of the treatment period (8 milkings per cow). Full-time cows had the lowest machine milk yields (mean ± SE; 6.1 and 6.0 ± 0.7 L at a.m. and p.m. milking, respectively), whereas part-time cows had similar yield to no-contact cows at a.m. milking (19.6 ± 0.7 L) and similar yield to full-time cows at p.m. milking (6.4 ± 0.7 L). Lower machine milk yields in cows with calf contact could not be fully attributed to milk consumption by the calf; however, they also could not be explained by differences in cow parity, calf sex, milking procedures (stimulation frequency; preparation duration), or stepping and kicking (restless) behavior at milking. All cows showed more restless behavior at p.m. milking, which weakly negatively affected machine milk yield, but this was unrelated to stimulation frequency in cow-calf contact cows, indicating that there may be other sources of discomfort or stress at the time of milking for these cows. Part-time versus full-time calf contact improved daily machine milk yields, but low machine milk yield issues merit further research so that cow-calf contact systems can be sustainable for producers.