The influence of prepartum feeding strategy on the initiation of parturition in Jersey cows
Dairy farming is a cornerstone of South Africa’s agricultural sector, contributing significantly to food security, employment, and the economy. The industry has shown resilience and adaptability, with a focus on increasing milk yield per cow, driven by advancements in genetics, feed quality, and management practices. Despite a decline in the number of dairy cows and farmers, total milk production has steadily increased, reflecting improved productivity. However, as the number of cows per farm grows, managing the transition period becomes increasingly complex. Globally, dairy producers thus need to investigate potential strategies to optimize supervision during the periparturient period and especially parturition to ensure the health of the cow and calf.
The present study evaluated the potential benefits of an afternoon feeding practice in pre-partum Jersey cows to increase the rate of daytime calving. The potential of the physiological changes associated with parturition to be used as potential bio-indicators of the onset of parturition in dairy cows, was also investigated. Furthermore, the effect of such a feeding strategy on calf health were also investigated. Pre-partum Jersey cows (± 30 days pre-partum) were assigned to either the Morning-fed (MF) treatment group, where cows were fed at 08h00 or the Afternoon-fed (AF) treatment group, where cows were fed at 17h00. The treatment groups were housed adjacent to each other, with access to feed and ad libitum water. This was done over a period of one year, with each treatment group consisting of 506 (MF) and 488 (AF) cows. In addition, to the primary year-long trial, thirty cows from each treatment group were randomly selected for the collection of specific bio-indicators, namely blood glucose levels and rectal temperatures. These were recorded daily from 14 days pre-partum, within two hours after calving, and again three days post-partum. For the purpose of this study, only data of cows that had Jersey heifer calves were included for the analysis of the calf health data. Consequently, the MF and AF treatment groups consisted of 203 and 198 cows, respectively.
The rate of daytime calving for cows in the AF treatment group was significantly higher than that of cows in the MF treatment group. In the AF treatment group, 54.30% of calvings occurred during the daytime and 45.70% at night, compared to 45.45% daytime and 54.55% nighttime calvings in the MF treatment group. Parity number, body conditioning score (BCS) upon entering the steam-up camp and the calf birth weight (BW) relative to the cow where similar between the treatment groups. However, the average live weight (LW) of cows upon entering the steam-up camp and average LW and body BCS at calving differed between the treatment groups. No difference was observed between time of parturition and the following cow parameters; parity number, average LW upon entering the steam up and at calving, BCS at calving, and calf BW relative to cow LW. No interactions were observed between the treatment groups and cow parameters by time of parturition. Generally, no effect between treatment and blood glucose levels or rectal temperature were observed. However, on day 13 and day two pre-partum an association was observed between treatment and blood glucose level. An association between treatment and rectal temperature on day one postpartum was also observed.
Overall, the time of feeding pre-partum Jersey cows had no effect on calf parameters (colostrum quality, colostrum intake (manually), calf birth weight, calf weaning weight and average daily gain). While time of parturition was not analysed as a primary factor, manual colostrum intake was slightly higher in calves born during the daytime, regardless of treatment group, with a notable interaction between treatment and parturition time. Time of feeding did not influence the incidence of neonatal diarrhoea, bovine respiratory disease, or joint-ill, though a significant association was found between the number of joint-ill treatments across the MF and AF treatment groups.
Afternoon feeding could indeed serve as an effective management tool to encourage daytime calving. However, further research is required to explore the effects of feeding time and other factors, such as diet composition, physical activity, photoperiod, and climatological variables, on the timing of parturition. Future studies should also investigate biological and chronobiological parameters that may help elucidate the unresolved physiological mechanisms underlying the impact of afternoon feeding in pre-partum dairy cows. Moreover, it is crucial to examine the broader implications of this feeding strategy on calf health. This can be achieved by analysing calf blood to assess passive immunity transfer and determine subsequent disease susceptibility.
Previous studies have demonstrated that afternoon feeding enhances daytime calving in both dairy and beef cows, a finding that was also observed in this study using pre-partum Jersey cows. It can be concluded that feeding pre-partum Jersey cows in the evening increases the likelihood of daytime calving, however the effect of such a feeding strategy on bio-indicators and calf health was not observed. Future research should prioritize investigating the physiological mechanisms behind this feeding strategy, along with other factors that might influence the timing of parturition. Additionally, it would be valuable for the dairy industry to examine the impact of afternoon feeding on calf health, as calves represent the future productivity of the herd.