Factors Affecting the Efficient Production of Boar Sperm.

Efficient sperm production in boars has developmental and functional components. Factors affecting the developmental phase influence Sertoli cell mitosis, appear to be mostly stimulatory and have permanent effects on production of sperm. Birthweight appears to hold promise as a prospective screening tool as it appears to have a strong positive relationship with adult sperm production. Strategic cross-fostering shortly after birth and socialization to humans between 4 and 9 weeks of age are strategies during the developmental phase that have been shown to increase spermatogenesis in adults. Factors affecting the functional phase influence the release of sperm by Sertoli cells and their subsequent maturation in the epididymi, appear to be mainly inhibitory and have temporary effects on spermatogenesis which can be corrected. The most common of these include exposure to elevated ambient temperature, nutrition, photoperiod, collection frequency and housing. Multiple deficiencies in several of these areas are common in commercial studs and have additive, negative effects on sperm production. However, there also is evidence that enhancements in one of these areas may be capable of offsetting deficiencies in others.