Periparturient Behavior of Beef Cows and Calves
Ramli, Abdullah Sani
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Crossbred and purebred gestating Angus and Hereford cows were monitored during the 1985 and 1986 spring calving seasons (number of calvings = 375). Cows were assigned randomly to one of two treatment groups that were balanced by breed-class, age and expected date of calving. The control group was fed corn silage at 0900 hours, and hay was available free choice. The treated group was fed the same diet but at 2100 hours, and time of access to the hay was restricted to between 2100 and 0900 hours. Each group was kept in a 3.2 ha paddock and observed continuously during the 1985 calving season. During 1986 similar treatments were used, but observations were not continuous. Data recorded were behavioral signs of parturition, times and locations of parturition and behaviors of cow-calf pairs observed continuously until 8 hours post-partum. Group diurnal activity patterns were recorded over 61 consecutive days in 1985. Post-partum behavior variables of the dam were time to first standing and grooming and total time spent standing, lying, grooming, browsing and eating. Calf variables were initial standing, teat seeking, mobility, suckling, total time spent on these activities and body weight at weaning. A significant (P <.05) shift in the diurnal activity patterns of the cows occurred when the feeding schedule was altered, but treatment did not affect (P>.10) the time of day when parturition occurred. The percentage of cows calving between 0600 and 1800 hours were 55 and 60 for the control and the treated groups, respectively. During the first 8 hours post-partum, differences in the time of onset and total time spent on some behaviors were determined to be related to breed of sire and dam, parity and sex of calf. Multiple regression of weaning weight on periparturient behavioral traits resulted in R2 values of 54 and 24% for heifer and bull calves, respectively. It was concluded that night-time feeding does not result in a significant increase in day-time calvings, and there is at least a moderate relationship between cow-calf behavior in the first 8 hours after birth and the calf's weaning weight.