Sperm Production Rate, Gonadal and Extragonadal Sperm Reserves of West African Dwarf Rams in the Southern Guinea Savannah of Nigeria

Abstract

Five healthy West African Dwarf (WAD) rams, 1.5 to 2.5 years of age and weighing between 15 kg to 20 kg were used to determine daily sperm production, gonadal and exragonadal sperm reserves. Gonadal and extragonadal sperm reserves were estimated by the haemocytometric method, while the daily sperm production was estimated from the gonadal sperm reserves. Daily sperm production x10⁹ and daily sperm production per gram testis x 10⁷ were 0.60 ± 0.01 and 0.94 ± 0.02 respectively. Mean gonadal sperm reserves x 10⁹ was 2.15 ± 0.11; mean caput, corpus, cauda and ductus deferens reserves x10⁸ were 1.79 ± 0.13, 0.75 ± 0.10, 3.77 ± 0.24 and 0.22 ± 0.06, respectively. The gonadal and extragonadal sperm reserves and daily sperm production values obtained in this study were lower than those reported for exotic breeds. High correlations were found between testis weight and daily sperm production (r = 0.81; P < 0.05), testis and testicular sperm reserves (r = 80; P < 0.05), caput weight and caput sperm reserves (r = 0.66; P < 0.05) corpus weight and corpus sperm reserves ( r = 0.54; P < 0.05), cauda weight and cauda sperm reserves ( r = 57; P < 0.05). This study has identified several important relationships among testicular characteristics and epididymal reserves that may be of value in improving breeding soundness examination of WAD rams.