Winter Infertilty.

Winter Infertilty.
Boar with winter infertility, one of 50 housed out of doors in Northern Iowa. Most boars had infertile semen and soft, small testicles. No frost bite per se. The problem was associated with stress and positioning the testicles up tight against the body. Several hundred boars exhibited this problem. Most regained fertility in 3 to 4 months.

Evans LE (2009)