kenny thomas wrote:
http://articles.extension.org/pages/393 ... eproducing
kenny thomas wrote:The very first sentence says it all. Twin to a heifer. Should have been castrated soon after birth.
Do you mind explaining a little more? We used a bull that was twin to a heifer for 6 years without ANY issues. He bred every cow that he had with him, they calved unassisted, and weaned decent. We have quite a few of his daughters in production, and have sold sons to folks from Oklahoma to Georgia.
The likeliness of reduced fertility of a male twin born co-twin to a heifer is a subject that still needs more investigation. There have been several small studies done over the last few decades and they've been largely inconclusive. Results range from a 58% reduction in fertility, to no discernible loss of fertility. Reduced scrotal circumference has been observed in one study, but not noted in any others that I could find. Sample sizes are all small due to a lack of subjects. While the research done thus far may be limited, the general consensus seems to be that the bull is safe to use if he passes a breeding soundness exam. Interestingly, among the studies performed in the seventies and eighties, there was a lot of interest in the sex ratios of among the progeny of the bulls, but none of the studies noted an imbalance and that was pretty much the end of research interest in the bull twins.
It seems to me that we're a ways off from being able to safely say one way or another if the bull twins are likely to have reduced fertility or not. I would personally lean towards castrating all bulls born co-twin to a heifer. The potential for reduced fertility, performance loss from being a twin, and the genetic predisposition to twinning are all concerns.