How Long Can Cows be Locked-up without Affecting Milk Production?
Research has shown that restraining cows in headlocks for four hours did not affect milk yield, milk fat percentage, somatic cell count or daily dry matter intake (Bolinger, et al., 1997), but milk protein percentages were slightly lower. The only major behavioral change observed to cows locked up for four hours was their acts of aggression were elevated during periods following restraint. Arava et al. found that lock-up was more stressful, as measured by blood cortisol increase, during hot summer days than during cooler spring weather. Based on these results and personal observations, it is felt that every effort should be made to minimize the amount of time cows are locked. Herd milking and animal treatment schedules should be coordinated so headlocks can be used without affecting milk production within reasonable stocking rate limits.
