Growth, carcass and meat quality characteristics of Small East African goats fed straw based diets

Abstract

Thirty-two castrated male goats of Small East African breed (13.8 kg BW, 12–18 months of age) were used to evaluate the potential of using treated-wheat straw alone or in combination with grass hay as dry season feeds. Animals were allotted into four dietary treatments with eight animals per treatment for 84 days. The dietary treatments were either ad libitum amount of untreated wheat straw (UTS), wheat straw treated with urea and lime (TS), untreated wheat straw with hay (UTSH) or treated wheat straw with hay (TSH). In addition, each animal received 220 g/day (on as fed basis) of a concentrate diet. Dry matter intake from wheat straws was highest (438.1 g/day, P < 0.05) for goats on TS. Daily body weight gain for goats fed TS was nearly two-fold higher than for those fed UTS. Meanwhile, goats fed TSH were more ( P < 0.05) efficient in converting feeds to body tissue as they required 9 kg less feed for one kg body weight gain compared to those fed TS. Goats on TS had the highest commercial dressing percentage (DP), which was about 5% higher than the DP of the other dietary groups. Compared to goats fed UTS, those fed TS had 0.70 and 0.32 kg heavier muscles and fat, respectively. Goats on diets including hay (TSH and UTSH) produced carcasses with higher proportion of fat than those without access to hay (TS and UTS). There was muscle-specific response to straw treatment with respect to cooking loss notably for M. gluteobiceps and M. triceps brachii. Chemical treatment of straws improved potentials for crop residues to sustain goats in the dry season with a minimum level of fattening. However, straw treatment had limited effect on the quality of goat meat. Grass hay complemented the effects of chemical treatment in increased intake and growth performance of goats.