Qi K, Lu C D, Owens F N, Lupton C J
Agricultural Research and Extension Programs, Langston University, OK 73050.
J Anim Sci. 1992 Sep;70(9):2828-37. doi: 10.2527/1992.7092828x.
Eight castrated male Angora goats were used in a repeated, simultaneous 4 x 4 Latin square designed experiment to evaluate metabolic and mohair responses of Angora goats to sulfate supplementation. Goats had ad libitum access to isonitrogenous diets containing a .16 (basal), .23, .29, or .34% S (DM basis), which yielded N:S ratios of 12.7, 8.3, 6.8, or 5.5:1. Feed intakes were not affected (P greater than .20) by dietary S level. Quadratic increases (P less than .05) to S supplementation were observed in grease and clean mohair production, grease and clean staple strength, and staple length. Mohair diameter, med fiber, kemp fiber, S, and cysteine contents were not affected (P greater than .05) by supplemental S. Averaged across the prefeeding, 2, 4, and 6 h postprandial sampling times, ruminal pH, ammonia N, total S, organic S, protein S, and plasma urea N and organic S concentrations were quadratically increased (P less than .05) by supplemental S. Ruminal sulfate S, total sulfide S, and plasma sulfate S were linearly increased (P less than .05) by supplemental S. Retention of N and mohair S yield exhibited quadratic increases (P less than .05), but S retention exhibited a linear increase (P less than .001) with increased S intake. Calculated by regression, the optimum dietary S concentration for maximum clean mohair production was .267% of dietary DM for a N:S ratio of 7.2:1, suggesting that the National Research Council N:S ratio of 10:1 is inadequate for Angora goats. The optimum level of digestible S was calculated to be .18% of the diet DM.
选用8只去势的雄性安哥拉山羊，按照重复、同步的4×4拉丁方设计进行试验，以评估安哥拉山羊对补充硫酸盐的代谢和马海毛反应。山羊可自由采食含硫量分别为0.16%（基础水平）、0.23%、0.29%或0.34%（干物质基础）的等氮日粮，相应的氮硫比分别为12.7、8.3、6.8或5.5:1。日粮硫水平对采食量没有影响（P>0.20）。随着硫补充量的增加，含脂马海毛产量、净马海毛产量、含脂毛丛强度、净毛丛强度和毛丛长度呈二次增加（P<0.05）。补充硫对马海毛直径、髓质纤维、死毛纤维、硫和半胱氨酸含量没有影响（P>0.05）。在预饲期、餐后2小时、4小时和6小时的平均采样时间，瘤胃液pH值、氨氮、总硫、有机硫、蛋白质硫以及血浆尿素氮和有机硫浓度随着硫补充量的增加呈二次增加（P<0.05）。瘤胃硫酸盐硫、总硫化物硫和血浆硫酸盐硫随着硫补充量的增加呈线性增加（P<0.05）。氮的保留量和马海毛硫产量呈二次增加（P<0.05），但硫保留量随着硫摄入量的增加呈线性增加（P<0.001）。通过回归计算，最大净马海毛产量的最佳日粮硫浓度为日粮干物质的0.267%，氮硫比为7.2:1，这表明美国国家研究委员会推荐的10:1的氮硫比对于安哥拉山羊来说是不够的。计算得出可消化硫的最佳水平为日粮干物质的0.18%。
