Nutritional effects on growth and carcass characteristics of Ankole, Nganda and Ankole x friesian crossbred bulls

Abstract

The study investigated the effect of protein supplementation on growth and carcass characteristics of grazing Ankole, Ankole x Friesian and Nganda bulls. Seventy two bull calves, 24 of each breed-type were randomly assigned to one of the three dietary treatments; the control of grazing alone (GZ), grazing followed by a 17.6% crude protein (CP) supplement (GZ + MD) and grazing followed by a 19.4% CP supplement (GZ + HG). The bulls were weighed fortnightly, and at the end of the feeding period all the bulls were slaughtered. Before slaughter, the live weight of each animal was taken, carcasses weighed hot, scored for grade and their dressing percentages determined. No significant (> 0.05) breed-type effects were observed in average daily gain (ADG). Significant variation (P <0.05) attributable to diet in ADG was observed. The supplementary diets (GZ+ MD and GZ+ HG) produced higher (P < 0.05) ADGs than the grazing alone diet. However, there were no significant (P>0.05) differences observed between the two supplementary diets. Significant variation (P <0.05) attributable to diet and breed-type in hot carcass weight, carcass grade and dressing percentage was observed. The (GZ + HG) bulls exhibited the highest (P < 0.05) dressing percentages, heaviest (P < 0.05) hot carcass weights and the highest (P < 0.05) carcass grades. The grazing alone diet averaged poorest and was significantly different (P < 0.05) from all the carcass measurements. Under the (GZ + HG) diet, the Ankole bulls possessed the highest (P <0.05) carcass grades and the heaviest (P < 0.05) hot carcass weights.