Boar sperm production in a tropical environment

Abstract

In a tropical environment, sow productivity is strongly associated with boar sperm production. Regular monitoring
of semen quality in boars that produce semen for artificial insemination is important. The objective of the present study
was to investigate the boar sperm production in an evaporative cooling system in a tropical environment in association
with breed and season. A total of 2878 ejaculates from 68 boars were collected from a boar stud in the western region
of Thailand. The breeds consisted of 22 Duroc, 22 Yorkshire, 18 Landrace and six hybrid boars. Seasons were classified
as cool, hot or rainy. Semen volume, sperm concentration, total sperm production and extended semen doses per
ejaculate were evaluated. The data were analysed by a general linear mixed model procedure. On average, the semen
volume, sperm concentration, total sperm production and extended semen doses per ejaculate were 256.2 ± 95.1 mL,
294.6 ± 125.0 × 106 sperm/mL, 70.2 ± 28.9 × 109 sperm/ejaculate and 16.2 ± 5.8 doses/ejaculate, respectively. In Duroc
boars, the semen volume, total sperm production and extended semen doses per ejaculate in the cool season were
higher than in the hot and rainy seasons (P < 0.05). However, most semen production traits did not differ significantly
among season in Landrace, Yorkshire and hybrid boars. In conclusion, seasons influenced the semen traits of Duroc
boars kept in an evaporative cooling system in Thailand.