Recent advances in boar management

Abstract Text: Sperm production in boars has both developmental and functional components. Management during the first 60 days of life coincides with active periods of Sertoli cell mitotic activity and has permanent effects on spermatogenesis. Birth weight appears to hold promise as a prospective screening tool for replacement boars as it has a strong positive relationship with adult sperm production. Boars weighing at least 1.5 kg at birth produced 10 billion more sperm per ejaculate compared with their counterparts weighing 1.0 kg or less. Strategic cross-fostering during lactation and socialization to humans between 4 and 8 weeks of age also have been shown to increase spermatogenesis. Ejaculates of boars allowed to nurse in litters of 6 contained more fertile sperm compared with those that were reared in a conventionally-sized litter of 9 or more. Socialization increased training success; libido; and sperm per ejaculate without any negative effects on sperm quality. Management of boars after puberty affects how efficiently sperm are produced by Sertoli cells and their subsequent maturation in the epididymis and has temporary effects on spermatogenesis which can be corrected in most cases. The most common of these include exposure to elevated ambient temperature, poor nutrition, inconsistent collection frequencies, and inadequate housing conditions. There is increasing evidence that most of the stresses in commercial production systems that affect semen quality and quantity appear to be multifaceted and chronic in they that are present at low levels over extended time periods. Consequently, multiple deficiencies that occur simultaneously are common and it is not until their additive effect reaches some presumed threshold that sperm production is compromised. Therefore, successful mitigation strategies to correct these problems that arise during the functional phase require a holistic approach which includes an assessment of all conditions and activities that have the potential to negatively affect sperm production in an additive fashion even though individually their impact may be minimal.

Keywords: Swine, boars, spermatogenesis