Effects of method of offering broiler litter and level of prairie hay intake on growth of Boer × Spanish wethers

Thirty-four <F>Boer×Spanish</F> wethers (<F>18±0.3</F> kg initial BW; 5 months of age) were used in a 12-week experiment (<F>2×2+1</F> factorial arrangement of treatments) to determine effects of ad libitum consumption of broiler litter (B) alone or mixed with corn (60% B; BC) and of ad libitum versus restricted (R) prairie hay intake on feed intake and growth performance. Treatments were: Control: ad libitum intake of hay plus an average of 26 g per day of a mineral-based supplement; AH-B: ad libitum intake of hay and B offered separately; AH-BC: ad libitum intake of hay and BC; RH-B: restricted intake of hay (approximately 1% BW; DM basis) and ad libitum intake of B; RH-BC: restricted intake of hay and ad libitum intake of BC. Average corn DM intake (DMI) was 179 and 170 g per day for AH-BC and RH-BC, respectively, and B DMI was similar among supplement treatments (<F>P>0.05</F>; 258, 271, 299 and 258 g per day for AH-B, AH-BC, RH-B and RH-BC, respectively). Hay DMI averaged 494, 442, 336, 175 and 160 g per day (<F>S.E.=16.7</F>), and total DMI was 516, 700, 782, 474 and 585 g/d (<F>S.E.=26.2</F>) for Control, AH-B, AH-BC, RH-B, and RH-BC, respectively. Overall ADG ranked (<F>P<0.05</F>) <F>AH-BC>AH-B</F> and <F>RH-BC>Control</F> and RH-B (-6, 34, 79, 3 and 50 g), and the ratio of ADG:DMI ranked (<F>P<0.05</F>) AH-BC and <F>RH-BC>AH-B>Control</F> and RH-B (-13, 49, 97, 5 and 85 g/kg) for Control, AH-B, AH-BC, RH-B and RH-BC, respectively. Total tract OM digestibility in period 2 ranked (<F>P<0.05</F>) <F>Control<AH-B</F>, AH-BC and <F>RH-B<RH-BC</F> (34.0, 46.6, 49.8, 50.0 and 63.7% for Control, AH-B, AH-BC, RH-B and RH-BC, respectively). Ruminal fluid ammonia N concentration was lowest among treatments (<F>P<0.05</F>) at 2 and 6 h after supplementation for Control (e.g., 6 h: 4.0, 19.5, 17.2, 38.2 and 25.8 mg/dl for Control, AH-B, AH-BC, RH-B and RH-BC, respectively; <F>S.E.=2.69</F>). The ratio of acetate:propionate was greatest among treatments (<F>P<0.05</F>) at 0, 2 and 6 h for Control (e.g., 6 h: 5.27, 4.04, 3.28, 3.64 and 3.10 for Control, AH-B, AH-BC, RH-B and RH-BC, respectively; <F>S.E.=0.218</F>). In conclusion, depending on production goals and availability of high-quality feedstuffs such as cereal grains, free-choice consumption of B may be a simple and useful method of supplementing low-quality forage. [Copyright &y& Elsevier]