日粮蛋氨酸锌水平对奶牛生产性能和血液指标的影响

Effects of dietary levels of Zinc-methionine on performance and blood parameters in lactating cows

选择8头泌乳早期的经产中国荷斯坦奶牛,采用4×4拉丁方设计,其中一组作为对照组,各试验组奶牛日粮中分别添加100、250、400 mg/kg蛋氨酸锌(按日粮干物质计),各组采用相同的基础日粮(含锌34.63 mg/kg干物质),观测其对奶牛生产性能、血液指标的影响。结果表明:试验组(100、250、400 mg/kg组)比对照组产奶量分别提高5.28%、7.79%和7.12%,差异显著(P<0.05),且250 mg/kg和400 mg/kg剂量组与对照组相比达到了极显著水平(P<0.01),但各试验组间无显著差异(P>0.05),试验组乳蛋白含量呈增加趋势(P>0.05),各组间乳脂、乳糖、非脂乳固形物含量均无显著差异(P>0.05),100、250、400 mg/kg组乳体细胞数分别降低10.43%、17.88%(P<0.05)和19.49%(P<0.05);各试验组乳锌、血清锌含量和碱性磷酸酶活性显著提高(P<0.01);蛋氨酸锌各添加组,尿素氮含量均呈下降趋势,但到差异不显著(P>0.05)。

Eight multiparous Holstein cows during early lactation were selected in a 4×4 Latin Square design and fed the identical basic dietary（Zn=34.63 mg/kg DM） to determine the effects of different levels of Zn-Met on performance and blood parameters.One was used as the control group and the remains were used as treatment groups which were added Zn-Met at 100,250,400 mg/kg of dietary DM.The results indicated that： The treatment groups（100,250 and 400 mg/kg） increased by 5.28%（P〈0.05）,7.79%（P〈0.01） and 7.12%（P〈0.01） in milk yields,but no significantly difference（P〉0.05） among the supplemental Zn-Met levels;No difference（P〉0.05） were noted among treatments in milk fat,protein,lactose and solids-not-fat,but the milk protein tended to be higher in supplemental Zn-Met treatments;The 100,250 and 400 mg/kg groups decreased by 10.43%,17.88%（P〈0.05） and 19.49%（P〈0.05） in somatic cell counts（SCC）;The milk Zn,serum Zn and alkaline phosphatase（AKP） activity significantly increased（P〈0.01） in cows fed Zn-Met;BUN tended to be lower in supplemental Zn-Met treatments,but no significantly difference（P〉0.05）.