Effect of graded levels and sources of protein on scrotal circumference and semen profile of Yankasa rams

Abstract

The effect of graded levels and sources of protein on scrotal circumference and semen profile in Yankasa rams were investigated in a 96 day study. Twenty Yankasa rams aged 18-24months and weighing 21-30 kg with clinically normal genitalia were divided into 4 groups (A, B, C and D) of 5 rams each. All animals were fed Digitaria hay as a basal diet ad libitum and supplemented with the formulated ration at 2% of their respective live-weights. Iso caloric rations (10.50 MJ/kg DM ME) were formulated using non-conventional protein source (maize offal and dry layer litter) to contain 12.11% CP, 14.96% CP, and 17.94% CP and fed to groups A, B and C respectively. Another ration was formulated using conventional protein source (maize, wheat bran, groundnut cake, bone meal, vitamin premix and salt) to contain 12.26% CP and fed to group D (control group). Semen was collected every two weeks with the aid of a battery powered electroejaculator and then evaluated. Rams on 12.11% CP had significantly higher scrotal circumference than those on 17.11% C. and control. Significantly higher (P<0.05) semen volume was recorded for group B when compared with control group, but other groups showed no significant difference in volume of semen (P>0.05). Rams fed 14.96% CP diet had significantly higher semen concentration when compared with rams on 17.94% CP and control (P<0.01). Percentage gross motility, sperm morphology, sperm output and sperm viability were not influenced by level and source of protein (P>0.05). Thus, it is evident from this study that dry layer litter and maize offal compete favorably with conventional protein sources in improving scrotal circumference and semen concentration of Yankasa rams.

Keywords: Dry layer litter, protein, rams, semen, scrotal circumference.