Luginbuhl J M, Poore M H, Conrad A P
Department of Crop Science, North Carolina State University, Raleigh 27695-7620, USA.
J Anim Sci. 2000 Jun;78(6):1677-83. doi: 10.2527/2000.7861677x.
Twenty-four purebred Boer (Capra hircus hircus) and 12 male kids of 1/2 Boer breeding (initial BW 21 +/- .5 kg) were used in a randomized complete block design to study the effects of increasing level of whole cottonseed (WCS) on ADG, serum urea N, plasma gossypol, live grades, and intake of DM, CP, NDF, ADF, hemicellulose, cellulose, lignin, ether extract, and free gossypol. A subgroup of 16 purebred goats was used to determine digestibility using a 5-d total fecal collection. Goats were blocked by BW and then assigned at random to one of four diets containing 0, 8, 16, or 24% WCS. All diets contained 71% chopped orchardgrass (Dactylis glomerata L.) hay and 29% concentrate; WCS replaced corn and soybean meal to maintain calculated TDN and CP concentrations at 68 and 15% of DM, respectively. Concentrations of NDF in diet DM were 52.4, 55.9, 59.3, and 62.1% with increasing WCS, and the Ca:P ratio was maintained at 2:0. Goats were given ad libitum access to feed and water. Over the 90-d performance phase, DMI (P < .05), CP intake (P < .02), and ADG (P < .01) decreased linearly with increasing WCS in the diet, whereas ether extract (EE) intake increased in a cubic fashion (P < .01). Gain:feed decreased linearly (P < .02) with increasing level of WCS. Addition of WCS resulted in linear decreases in apparent digestibility coefficients of DM (P < .02) and NDF (P < .05), a linear increase in total plasma gossypol (P < .01), and a quadratic increase in serum urea N (P < .04). Apparent digestibility of CP was not affected by WCS level. At the 16 and 24% WCS levels, EE constituted 4.2 and 4.8% of total DMI, respectively. Adding WCS to diets for growing goats had detrimental effects on animal performance, and, based on the possible negative effects of dietary EE and NDF rather than gossypol, economics should dictate whether to use WCS in feeding programs.
选用24只纯种布尔山羊（Capra hircus hircus）和12只1/2布尔山羊杂交公羔（初始体重21±0.5千克），采用随机完全区组设计，研究全棉籽（WCS）添加水平增加对平均日增重（ADG）、血清尿素氮、血浆棉酚、胴体等级以及干物质（DM）、粗蛋白（CP）、中性洗涤纤维（NDF）、酸性洗涤纤维（ADF）、半纤维素、纤维素、木质素、乙醚提取物和游离棉酚摄入量的影响。选取16只纯种山羊组成一个亚组，采用5天全粪收集法测定消化率。山羊按体重进行分块，然后随机分配到四种日粮之一，日粮中WCS含量分别为0%、8%、16%或24%。所有日粮均含有71%的切碎果园草（鸭茅）干草和29%的精料；WCS替代玉米和豆粕，以使计算得出的总可消化养分（TDN）和CP浓度分别维持在干物质的68%和15%。随着WCS含量增加，日粮干物质中NDF浓度分别为52.4%、55.9%、59.3%和62.1%，钙磷比维持在2:0。山羊可自由采食饲料和饮水。在90天的生长性能期内，随着日粮中WCS含量增加，干物质采食量（DMI，P<0.05）、CP摄入量（P<0.02）和ADG（P<0.01）呈线性下降，而乙醚提取物（EE）摄入量呈三次方增加（P<0.01）。料重比随着WCS添加水平增加呈线性下降（P<0.02）。添加WCS导致DM（P<0.02）和NDF（P<0.05）的表观消化率系数呈线性下降，血浆总棉酚呈线性增加（P<0.01），血清尿素氮呈二次方增加（P<0.04）。CP的表观消化率不受WCS水平影响。在WCS含量为16%和24%时，EE分别占总DMI的4.2%和4.8%。在生长山羊日粮中添加WCS对动物生产性能有不利影响，基于日粮中EE和NDF可能产生的负面影响而非棉酚，经济因素应决定是否在饲养方案中使用WCS。
