本试验通过研究饲粮锌水平对生绒期陕北白绒山羊生长性能、产绒性能及绒生长相关激素含量的影响，旨在确定生绒期陕北白绒山羊饲粮适宜的锌水平。采用单因素随机区组设计，将32只体况良好及体重相近的8月龄陕北白绒山羊随机分为4组，每组4个重复，每个重复2只。对照组（Ⅰ组）饲喂基础饲粮（锌水平为28.57 mg/kg DM），3个试验组（Ⅱ、Ⅲ、Ⅳ组）分别饲喂在基础饲粮中添加饲料级硫酸锌的试验饲粮，试验饲粮锌水平依次为50、70和100 mg/kg DM，预试期15 d，正试期6个月。结果显示：1）饲粮锌水平对陕北白绒山羊干物质采食量（DMI）及料重比（F/G）均无显著影响（P>0.05）。Ⅲ组山羊的平均日增重（ADG）最高且与Ⅰ组差异显著（P<0.05），而与其他2组差异不显著（P>0.05）。2）饲粮锌水平对试验初和试验末羊绒细度及产绒量均无显著影响（P>0.05）。试验末羊绒长度Ⅲ组显著大于Ⅰ组（P<0.05），而Ⅳ组则极显著大于Ⅲ组（P<0.01），显著大于Ⅱ组（P<0.05）。Ⅲ组羊绒生长量及羊绒生长率均显著高于Ⅰ组及Ⅳ组（P<0.05），与Ⅱ组无显著差异（P>0.05）。3）随着陕北白绒山羊生绒期的推进，血清褪黑激素（MT）、胰岛素样生长因子-1（IGF-1）及生长激素（GH）含量均呈现增加趋势，而血清催乳素（PRL）含量则呈降低趋势。饲粮锌水平对陕北白绒山羊试验期内血清MT、PRL含量及试验中期GH含量均无显著影响（P>0.05）。试验中期Ⅲ组血清IGF-1含量显著高于Ⅳ组（P<0.05）。试验末期Ⅲ组血清IGF-1含量显著高于Ⅰ组及Ⅳ组（P<0.05）。试验末期Ⅲ组血清GH含量显著高于Ⅰ组（P<0.05）。综上，生绒期陕北白绒山羊饲粮适宜的锌水平为70 mg/kg DM。

This experiment was conducted to study the effects of dietary zinc level on growth performance, cashmere performance and cashmere growth-related hormone contents of Shanbei white cashmere goats during cashmere growing period, in order to determine the optimal dietary zinc level of Shanbei white cashmere goats during cashmere growing period. The experiment was designed in a single factor random block. Thirty-two Shanbei white cashmere goats at 8 months of age with physical fitness and similar weight were selected and divided into 4 groups with 4 replicates per group and 2 goats per replicate. The goats in control group (group Ⅰ) were fed a basal diet containing 28.57 mg/kg DM zinc, and the goats in experimental groups (groups Ⅱ, Ⅲ and Ⅳ) were fed the basal diet supplemented with zinc sulfate (feed grade), and the dietary zinc level of the experimental diets was 50, 70 and 100 mg/kg DM respectively. The pre-test period was 15 days and the formal test period was 6 months. The results showed as follows:1) dietary zinc level had no significant influences on dry matter intake (DMI) and feed/gain (F/G) of Shanbei white cashmere goats (P>0.05). Goats in group Ⅲ had the greatest average daily gain (ADG), and the ADG in group Ⅲ had significant difference compared with group Ⅰ (P<0.05), while had no significant difference compared with groups Ⅱ and Ⅳ (P>0.05). 2) Dietary zinc level had no significant influences on cashmere diameter at initial experiment and last experiment and cashmere production (P>0.05). Cashmere length in group Ⅲwas significantly higher than that in group Ⅰ (P<0.05). Cashmere length at last experiment in group Ⅳ was significantly higher than that in groups Ⅲ and Ⅱ (P<0.01 and P<0.05, respectively). Cashmere growth and cashmere growth rate in group Ⅲ were significantly higher than those in groups Ⅰ and Ⅳ (P<0.05), and no significant difference was observed between groups Ⅲ and Ⅱ (P>0.05). 3) With the succession of cashmere growing period, melatonin (MT), insulin like growth factor-1 (IGF-1) and growth hormone (GH) contents in serum of goats showed increasing trend, and serum prolactin (PRL) content was showed decreasing trend. Dietary zinc level had no significant influences on serum MT and PRL contents in the whole experiment period and GH content in the mid-term experiment (P>0.05). Serum IGF-1 content in the mid-term experiment in group Ⅲ was significantly higher than that in group Ⅳ (P<0.05). Serum IGF-1 content in the last experiment in group Ⅲ was significantly higher than that in groups Ⅰ and Ⅳ (P<0.05). Serum GH content in the last experiment in group Ⅲ was significantly higher than that in group Ⅰ (P<0.05). In summary, the optimal dietary zinc level of Shanbei white cashmere goats during cashmere growing period is 70 mg/kg DM.