PSX-13 Effects of the dietary concentrate level and harvest weight on growth performance and harvest traits of Boer and Kiko growing kids.

Abstract Goat meat production is affected by different factors such as breed, age, and diet. The aim was to determine the effects of dietary concentrate level and harvest weight on growth performance and harvest traits of Boer and Kiko growing goats. Seventy-two kids (36 Boer and 36 Kiko, one-half wethers and one-half doelings, 5 mo of age and 20.3±0.51 kg BW) were used. Diets with 30% (30C) and 70% (70C) concentrate were used, with lespedeza hay as the only forage source. In the first 64 days, all kids were fed the 30C diet, after which 24 kids were slaughtered (D1=30C, 64 days). The last 76 days, 24 kids from each breed were kept on the 30C diet (D2=30C, 140 days) and the other 24 were fed the 70C diet (D3=70C, 140 days), after which harvest traits were determined. Data were analyzed as a 2×3 factorial arrangement of treatments. Dry matter intake (DMI) was similar among dietary treatments (P >0.05; 78.6, 74.3, and 77.4 ± 1.89 g/kg BW0.75 for D1, D2, and D3, respectively) and greater (P< 0.01) for Boer than for Kiko (81.1 and 72.4 ± 5.51 g/kg BW0.75, respectively). Average daily gain differed among dietary treatments (P< 0.05; 60.1, 56.1, and 93.8 ± 3.48 g/day for D1, D2 and D3, respectively). There was an interaction (P< 0.01) between breed and diet for body weight gain (WG) and carcass weight (CW). There was no difference (P >0.05) between Boer and Kiko kids on D1, but Boer kids performed better (P< 0.01) when fed D2 and D3 for both variables with the greatest value for D3 in Boer goats (WG: 4.88, 9.52, and 15.54 kg for Boer and 3.45, 6.27, and 10.78 ± 0.584 kg for Kiko; CW: 9.59, 12.86, and 17.40 kg for Boer and 9.55, 11.58, and 14.81 ± 0.499 kg for Kiko on D1, D2 and D3, respectively). Dressing differed (P< 0.05) among diets (39.5, 43.0, and 48.5 ± 0.64 % for D1, D2, and D3, respectively. Carcass protein content was similar (P >0.05) for D1 and D3 (18.0 and 17.5 ± 0.40 %) but was higher (P< 0.05) for D2 (18.8 ± 0.04), and there were no differences (P >0.05) between breeds (18.5 and 17.7 ± 0.53 %, respectively). The carcass fat content was highest (P< 0.01) for D3 and similar (P >0.05) for D1 and D2 (20.0, 16.0, and 14.8 ± 0.63 %, respectively). The carcass of Kiko contained higher fat percentage than Boer goats (17.9 and 16.0 ± 0.52, respectively). In conclusion, DMI was not affected by concentrate level and BW gain was higher by extending the feeding period, and Boer kids were heavier than Kiko but carcass fat content was higher in the latter.