Frost on Bull Testicles 

Extreme cold in the preceding winter can result in frost damage to bulls testicles. Consider reviewing your breeding programs and plans, especially if there are any concerns about the soundness of your present bull battery.

Frostbitten testicles can have a significant effect on bull fertility, due to testicular damage and impaired sperm cell production. To accurately assess the damage due to frostbite, producers should have their bulls put through a breeding soundness evaluation.

Severe frost damage may be detectable on physical examination of the scrotum and testicles, and some bulls may indeed be culled on this basis alone. More moderate frost damage will show up as abnormalities in sperm morphology. A complete bull evaluation, including a examination of all sexual organs, a measurement of scrotal circumference, and a detailed semen evaluation will determine if the frost damage has had a significant, and permanent effect on the bull's fertility. Based on the results of the evaluation, your veterinarian will predict whether the bull has had damage, if and when the bull will recover, and whether the bull should be culled.

It makes good sense to contact your local veterinarian and discuss a bull evaluation. Bull sales are rapidly approaching, and although breeding season may seem far away, it is better to know if you have a problem now than to find out later and have to rush your bull purchases.

Consider the effect that an unsound bull can have on your gross revenue next fall: if your breeding season is 83 days (four heat periods) and your bull does his best job with no problems, resulting in a 70-20-10 settling rate on 100 cows (70% of the cows bred in the first 21 days, 20% of the cows bred in the second 21 days, etc.) a calf growth rate of 2.65 lbs/day, and weaning at 200 days, you would end up with 59,440 lbs of weaned calf, or an average of 594 lbs of weaned calf per cow exposed next year.

If your bull has a problem, and is not capable of servicing the cows for a portion of the breeding season due to disease, frost damage, lameness or too many cows to service, and you end up with a 40-10-40-10 settling rate on your cows, you will end up with only 54,820 lbs of weaned calf or an average of 548 lbs of weaned calf per cow, a difference of 46 lbs of weaned calf per cow.

Contact: Melinda German and Terry Whiting, Manitoba Agriculture, Food and Rural Initiatives