Songklanakarin Journal of Science and Technology (SJST) (Mar 2007)
Effects of protein levels in concentrate and rice straw or urea-treated rice straw on growth performance, carcass characteristics and consumer acceptance of meat from goat and sheep
Abstract
The objectives of this research were to study the effect of protein levels in concentrate and rice straw or urea-treated rice straw on growth performance, carcass characteristics and consumer acceptance of meatfrom goat and sheep. Sixteen male goats and sixteen male sheep, with the initial weight of 20-25 kg, were randomly assigned to an individual pen and received the experimental diets. A 2x2x2 factorial experiment in completely randomized design (CRD) was applied with 4 replicates per treatment. The treatments werecombined by two animal species (goat and sheep), two levels of crude protein (CP) in concentrate (14 or 16% CP) and two types of roughages (rice straw or 5% urea-treated rice straw). The diets were fed ad libitum foreach animal and the feeding trial lasted for 91 days. The results showed that average daily gain among treatment groups were not significantly different (P>0.05) but that of goat and sheep receiving urea-treated ricestraw was higher (P0.05) across treatments. Total feed intake of sheep was higher than of goat (964.5VS 749.9 g/d). Total feed intake of goat and sheep receiving urea-treated rice straw were higher than those receiving rice straw (90.1.7 VS 817.4 g/d). Digestion coefficients of dry matter (DM) and nutrients weresignificantly different among treatments (P0.05). Percentage of shank and heart in goat (29.4 and 0.63%) were higher than that in sheep(24.6 and 0.56%); however, its skin percentage was lower than in sheep (13.87 VS 16.83%). Most wholesale cuts of all treatments were not significantly different (P>0.05). However, percentage of neck cut, shouldercut and shank cut in goat (8.22, 24.07 and 7.77%, respectively) was higher than that in sheep (6.79, 21.63 and 5.68%, respectively). Percentage of loin cut and leg cut in sheep (9.64 and 33.24%) were higher than that ingoat (7.33 and 29.02%). Carcass length, back fat thickness, shear force and loin eye area of all treatments were not significantly different (P>0.05). Back fat thickness of sheep was higher than that of goat (0.24 VS0.13 inch). Chemical compositions of meat were not significantly different (P>0.05) among treatments. Moisture and protein of chevon (73.96 and 76.37%) were higher than mutton (71.61 and 70.69%). However,fat percentage from mutton was higher than that of chevon (21.37 VS 16.29%). Consumer acceptability test of all treatments revealed that mutton was more tender, juicier, tastier and received a higher level of acceptancethan chevon (P<0.01). These results would be due to the unaccustomed odor of the chevon by Thai consumers.
