Winter Bull Management
Protection from inclement weather is a critical factor in winter herd bull management because of the very real concern of frostbite of the scrotum. While mild frostbite generally has a good recovery rate, severe frostbite can leave a bull infertile. Scarring from frostbite can hinder a bull’s ability to raise and lower the testicles for proper temperature regulation. This regulation depends on coordination of three structures: the tunica dartos muscle in the walls of the scrotum, which relaxes when hot and contracts when cold; the external cremaster muscle within the spermatic cord, which lengthens or shortens to lower or raise the testicles depending on temperature; and the pampiniform plexus, which is a coil of veins that provide an effective countercurrent temperature exchange by cooling arterial blood entering the testicle and transferring its heat to the venous blood leaving the testicle. Normal sperm formation only occurs at 4-5 degrees below body temperature, so any damage to any of these three structures could result in infertility. Pull up that National Weather Service wind chill chart and take a look at some of the effective temperatures we’ve experienced already this winter. The frostbite warning zones aren’t going to be much different for that vital part of bull anatomy than they are human skin. You’ve invested in those herd bulls for the future of your cow herd and sustainability of your ranch. Ensure that bulls have the ability to get out the wind and are not lying on unbedded, frozen ground. Putting testicles on ice is not conducive to fertility.
The article was written by Rachel Endecott (MSU Extension Beef Cattle Specialist). For further information on livestock management, please contact the Chouteau County Extension Office at 622-375, or stop in for a visit in the courthouse basement.
Montana State University U.S. Department of Agriculture and Montana Counties Cooperating. MSU Extension is an equal opportunity/affirmative action provider of educational outreach.
