PS10-28. Performance and Harvest Traits of Boer and Boer x Spanish Growing Goats Fed Diets with Different Concentrate Levels.

Abstract The objective was to evaluate the performance and harvest traits of Boer (B) and Boer x Spanish (BxSp) growing goat fed diets with different concentrate levels. Two diets were used: 30% and 70% concentrate, with lespedeza hay as forage source. Seventy-two kids (36 B and 36 BxSp), including 18 intact males and 18 wethers per breed, with 4.5 months of age and 18.46±2.89 kg of body weight (BW) were used. All kids were fed the 30C diet for the first 76 days, after which 24 kids were slaughtered (T1=30C, 76 days). The following 70 days, 24 kids from each breed continued on the 30C diet (T2=30C, 146 days), whereas the other 24 were fed the 70C diet (T3=70C, 146 days), after which harvest traits were determined. Dry matter intake was higher (P < 0.01) for T1 but similar between T2 and T3 (3.76, 2.97, and 2.81 ± 0.049 % BW, for T1, T2 and T3, respectively), and similar (P > 0.05) between genders (3.16 vs 3.19 ± 0.604 % BW, for intact males and wethers, respectively). Daily gain (DG) and feed efficiency (FE) were greater (P < 0.01) for T3 than for T1 and T2 (DG: 109, 109, and 138 ± 5.8 g/day; FE:127, 137, and 173 ± 5.1 g/kg DM, for T1, T2, and T3, respectively). Carcass weight (CW) and dressing percentage differed (P < 0.01) among treatments (11.2, 15.8, and 18.0 ± 0.38 kg; 41.9, 44.4, and 46.9 ± 0.43%, for T1, T2 and T3, respectively). CW was greater (P < 0.01) for BxSp than B goats (15.7 vs 14.0 ± 0.31 kg) and for intact than wether goats (15.4 vs 14.2 ± 0.31 kg). Protein content in carcass was highest (P < 0.01) in T2 than in T1 and T3 (18.6, 19.1, and 18.4 ± 0.10%, for T1, T2, and T3, respectively), but breed performed similarly (P > 0.05) (18.6 vs 18.7 ± 0.08% for B and BxSp, respectively). Carcass of intact males had greater (P < 0.01) protein content than wethers (19.0 vs 18.3 0.08%, respectively). Carcass fat content was lowest in T2 than T1 and T3 (15.6, 13.2, and 16.1 ± 0.48%, for T1, T2 and T3, respectively), higher in BxSp than B (15.9 vs 14.0 ± 0.39%), and lower for intact than wether goats (13.3 vs 16.0 ± 0.34%). Although DMI was lower for T3 than T1 and T2; DG, FE, CW and dressing were greater for the former. Lengthening the feeding period and increasing concentrate level in the diet increased CW and dressing; however, the higher concentrate level negatively affected meat quality.