Abstract

Fifteen WAD bucks aged 10 - 12 months and weighing between 14.0 and 16.5 kg were used to determine the relationship between scrotal circumference (SC), in situtesticular measurements and sperm reserves. The in situ testicular measurements were testis length (TL) and testis width (TW) and these were compared with ex situmeasurements (in excised testes). The results showed no significant (P>0.05) differences between in situ and ex situ measurements of TL and TW. SC had highly significant (P<0.01) correlation with testis (0.86) and whole epididymal (0.78) sperm reserves. SC was also significantly correlated with TL (0.72) and TW (0.65), while TL and TW (in situ) were correlated respectively with testis sperm (0.70 and 0.55) and epididymal sperm (0.74 and 0.50) reserves. It was concluded that measurements of SC, TL or TW would provide a reliable guide to sperm production capacity of testis in WAD bucks and that these measurements can be applied by farmers in selecting bucks for breeding purposes.

Key words: Bucks, testicular measurements, sperm reserves, scrotal circumferences.