The effects of seasons of birth on body and testis growth of large white and large white X IND F₁ crossbred boars in a humid tropical environment

Abstract

This study was conducted to find out the effects of season of birth (SOB) on body and testis growth in the Large White (LW) and Large White x Indigenous (LWXIND F₁) crossbred boars in a humid tropical environment. 21 weaner boars of each genotype born in the Dry season (DS) and rainy season (RS) were used and their body and testis growth monitored by determining body weight and linear body and testis measurements at regular intervals from 8-36 weeks of age. The results obtained showed significant effects (P<0.05) of season of birth (SOB) on body weight, feed intake, feed/gain and linear body measurements of LW boars but no significant (P>0.5) effects of SOB on these traits in the crossbreds. The Genotype x SOB interaction effects on body weight were significant (P<0.05). Also, all testis measurements were significantly (P<0.5) affected by SOB in both LW and LW x IND F1 boars. The interaction effects (Genotype x SOB) on testis measurements were significant (P<0.05). These results indicate that body growth in LW boars is sensitive to elevated environmental temperature that characterizes the dry season in tropical climate, while the crossbred boars are resistant to such condition. The results also showed that boars of both genotypes reared in the DS had lower testis growth than those reared in RS which results may have far-reaching implications on the reproductive performance of boars in this climate.

Keywords:Season, testis, boars, growth, humid tropics.

> Agro-Science Vol. 6 (1) 2007: pp. 98-105