Influence of heat stress on the quality of sperm production of boars-producers of different breeds and its fertilizing ability

Abstract

The primary purpose of this work is to study the heat stress on the quality of sperm production in boars of different breeds (Large White, Landrace, Duroc, Maxgro). The authors found that heat stress affects the activity of pigs. The desire to reduce heat production leads to sedentary, passive animals, accompanied by decreased appetite, shortness of breath and inhibition of sexual reflexes in individuals. Against this background, the disturbances arising in the body, reinforced by a local increase in scrotal temperature, harm semen quality. The authors observed a tendency for decreased ejaculate volume and a decrease (statistically significant in most breeds) in the sperm concentration in the ejaculate by 11.47-34.96%. But at the same time, the organoleptic values (colour, consistency, smell) did not change. Heat stress hurts the fertility of pigs, reducing the probability of successful embryo implantation. The fertility of sow inseminated with semen from boars during heat stress decreased by 10.3-23.7%. And also, the fertility of the sow did not reach pre-stress levels until the end of the observation. Based on the study results, the authors found that, depending on the breed, pigs can tolerate heat stress in a more severe or milder form. The species Large White and Maxgro are less sensitive to increased ambient temperature (they had fewer changes in general condition, semen and fertility) than Duroc and Landrace pigs.