Testicular sperm reserve of Sokoto red and Sahel bucks from Mubi main slaughter house Adamawa state, Nigeria

Abstract

The study was conducted to evaluate testicular sperm reserve of red Sokoto and Sahel bucks in relation to effects of year, season, breed, age, live weight and body condition score. A total of 32 bucks of 12 months old comprising 16 from each breed were obtained from small scale subsistence
farmers at Mubi livestock market. These animals were raised across four seasons, early dry, late dry, early wet and late wet for the period of two years. Animals were aged by dentition method, weight determined by clinical weighing scale and body condition scores determined using Scale six grades 0 – 5. Scrotal circumference was determined in cm using a flexible metric tape before the animals were slaughtered. Testicular measurements were carried out post-mortem and the testes preserved in an ice box before being taken to the laboratory. The gonadal and epididymal sperm reserve were determined. The results revealed that, there were no significant differences (p>0.05) among variables RTSR, LTSR and PTSR for year 2008 and 2009. But significant (p<0.001) seasonal effect was observed, with early dry season having the highest values followed by late wet season and early wet season having the least values among the variables. Least sperm reserve values for right, left and paired testes were observed during the early wet season. Also, a significant
(p<0.001) breed difference was observed with respect to testes sperm reserves, with largest volume in Sahel bucks, while the values in Sokoto Red were lower. Age group variability significantly (p<0.001) influenced sperm production ability of bucks. Age group >3 years recorded highest sperm reserves. Correlation matrix showed significant (p<0.001) positive correlation (r=0.58, 0.75, 0.69, 0.77, 0.76, 0.67, 0.77, and 0.78,) between live weight, BCS, SC, WLTLG,WLTVL, WLTWT, WRTLG, WRTVL, and WRTWT. Very highly significant (p<0.001) negative correlations (r-values) were observed between age, Season and humidity and all testicular
parameters measured. Testicular variables and testicular sperm reserves showed very highly significant (p<0.001) correlation (r-values) between live weight and all other variables, and highly significant (p<0.001) negative correlation (r-values) between age, humidity and the rest of the variables. It is concluded that, goats are very conscious of seasonal variation in the quality, availability of crop residues and liberty to select, scavenge with aversion to high humidity. These affect their general performance in life. Livestock producers are advised to take note of these findings to enable them plan adequately in order to achieve their targets.

Keywords: Sperm Reserve, Sokoto Red, Sahel, Bucks, Mubi, Adamawa State, Nigeria