We have received some questions about the appropriate weight to breed crossbred heifers. At Virginia Tech, we have used 650 lbs as the minimum body weight to breed HJ or JH heifer, while limits of 550 and 750 lbs are used for Jersey and Holstein heifers.
The purebred limits work well, and the 650 lb limit is successful for the HJ and JH animals. Our HJ and JH crosses have been bred to Brown Swiss and Swedish Red bulls for the past three years. We have established a 750 lb minimum for Brown Swiss sired heifers, but have settled on a 700 lb minimum for Swedish Red sired heifers, as the SRB is a somewhat smaller breed than Brown Swiss. We tried 650 lbs for the BS and SRB sired heifers at first
They conceived well enough at that weight, but the half dozen or so of BS and SRB sired heifers bred at 650 lbs entered the herd at 21 - 22 months, and seemed to struggle a bit. Our HJ and JH heifers were just a bit older when bred at the same weight were ready to go when they first freshened as young cows. Bottom line - my recommendations for weight at first breeding:
- Holstein - 750 lbs
- Jersey - 550 lbs
- Jersey - 550 lbs
- SRB sired heifers out of HJ or JH dams - 700 lbs
- BS sired heifers out of HJ or JH dams - 750 lbs
Today, all crossbred animals in the Virginia Tech herd are mated to Holstein and Jersey bulls, as we return to two pure breeds following the crossbreeding trial. We intend to manage all of those backcross heifers, regardless of breed composition, as purebreds of the backcross breed as they approach breeding age. This will simplify heifer management initially, and will be the appropriate strategy in succeeding generations as the percentage of the backcross breed increases.
By Bennet Cassell, Extension Dairy Scientist
Dairy Pipeline newsletter (April 2009) - Virginia Cooperative Extension