We aimed to evaluate the effects of organic herbal preparations containing rumen-protected choline (RPC) in dairy cow milk’s BHB and progesterone (P4) concentration changes, reproduction, and production performances. Cows were divided into the following two groups: The CHOL (n = 60) cow diet was supplemented with 10 g/day RPC from 20 days pre-calving to 20 days post-calving, and CONT (n = 60) were fed a conventional diet. BHB and P4 concentrations were measured at 5–64 DIM and 21–64 DIM, respectively, with DelPro 4.2. BHB was lower in the CHOL group at 5–64 DIM than CONT p > 0.05. The first post-calving P4 peak, p < 0.001, was determined earlier in the CHOL group, and the P4 profile during 21–64 DIM was similar, p > 0.05. The insemination rate was lower, and the interval between calvings was shorter. The first insemination time was earlier in the CHOL group, p < 0.05. Milk yield was higher in the CHOL group at 21–64 DIM, p > 0.05. The CHOL group had more fat in their milk at 31–60 DIM, p < 0.05. There were no significant differences in protein and SCC between the groups, p > 0.05. Based on our results, we concluded that the supplementation of RPC pre- and post-calving had statistically significant effects on the first peak of P4, and benefited the reproduction performances, milk yield, and milk fat during the early postpartum period.

The objective of this study was to evaluate the impact of cows’ calving ages and newborn calf body weight on the pre-weaning growth rates of calves under the farming conditions of a northeastern European country. The females were purebred Charolais cows that calved between 2019 and 2022. A total of 130 calves (bulls = 76; heifers = 54) were observed during the evaluation. The investigation showed that, based on gender, bulls had a 4.28% higher birth weight than heifers (p < 0.05). The gender of the calves affected their weight, indicating that newborns bulls were significantly heavier. Calf gender affected calf growing performance. Male calves’ weight gain was higher than that of females in the time before weaning (210 days). The highest gain of bulls was observed from 211 days to 365 days after birth. The average daily weight of male calves during this period was 6.16% (p < 0.001) higher compared to the period up to 210 days after birth. Heifers had a higher daily weight in the period up to 210 days after birth, and the daily weight gain was 12.9% (p < 0.001) higher in this period compared to the period from 211 to 365 days after birth. We observed a higher weight gain in calves from mothers with a higher number of calvings. Being born from cows with four or more calvings had a significant effect on the weight gain of calves in the period up to 210 days (p < 0.05). In the period up to 210 days, the weight gain of calves born from cows with two calvings was the lowest and was 9.79% lower compared to calves born from cows with four and more calvings (p < 0.05). The best weights were obtained from calves born in the spring and autumn seasons. Calves born in spring, summer, and autumn differed in weight by 0.37 kg. The calves of cows that were inseminated in the autumn season had the highest gain in the period up to 210 days and also from 210 to 365 days (p < 0.05). In our study, significantly higher average birth weight of calves was detected in autumn compared to summer and winter (p < 0.05). Also, the highest gain was found from 211 to 365 days after birth in the summer season, but the difference was only 1.47% (p < 0.05).

The objective of this study was to determine the effectiveness of mycotoxin management with feed additive by monitoring biochemical blood parameters, reproduction status and udder health in cows. During the first 1-12-months, the reproduction performance was assessed. The cows were fed only total mixed ration (TMR) with naturally contaminated mycotoxins (ZEN;DON;AFB1;OTA) and the cows were regarded as a control group (CG). In months 13-15, two groups were created: control (CG)(n=30) and experimental (EG)(n=60). The CG was fed with contaminated TMR and the EG was fed with the same TMR+40g/cow mycotoxins management feed additive (TMXL1000). During this period, blood indicators and udder health were studied. Beginning with months 16-24, all cows were fed with contaminated TMR+40 g/cow (TMXL1000) and regarded as the EG. The IgA concentrations in the CG decreased in the 15th month (p<0.05). The concentrations of cortisol decreased by two times (p<0.05) in the EG. Ovarian cyst treatment was more effective by 14.98% (p<0.05) in the EG than in the CG (p<0.05). The EG performed an effective (18.02%) (p<0.05) response to applied ovsynch protocol compared with the CG. According to the obtained results, it can be concluded that feed additive for mycotoxins management had a positive impact on dairy cow health.

Hyperketonemia is a very common metabolic state in dairy cows, which result in lower milk production, impaired fertility, and increased frequency of other diseases. In this study, we aimed to determine the influence of season, parity, and milk yield of cows on beta-hydroxybutyrate (BHB) concentration in the second week of lactation (WK 2) and establish the relationship between BHB concentration in WK 2 and reproduction performance traits such as insemination rate and first insemination day of Lithuanian Black and White dairy cows. The study included clinically healthy Lithuanian Black and White cows (n = 692). Blood BHB concentration was measured using capillary blood samples collected after morning milking when cows were 7–10 DIM. The impact of WK 2 blood BHB concentration on the insemination rate and first insemination day were investigated. The effect of BHB was evaluated according to the season, parity, and milk yield per lactation (305 DIM). Significant differences were observed in BHB concentration in WK 2 due to season and parity, but no statistically significant differences were observed for milk yields (305 d). Increased blood BHB concentration in WK 2 negatively affected insemination rate (p < 0.001) and first insemination day (p < 0.001). The study findings indicate that BHB concentration in WK 2 depends on season and parity, while the milk yield is not associated with BHB concentration. High BHB concentration in WK 2 increases insemination rate and delays the first insemination day for high milk-yielding Lithuanian Black and White dairy cows.