半胱胺盐酸盐对泌乳奶牛生产性能和血清激素水平的影响

Effects of Cysteamine Hydrochloride on Performance and Serum Hormone Levels of Lactating Dairy Cows

本试验旨在确定半胱胺盐酸盐（cysteamine hydrochloride,CSH）在中国荷斯坦奶牛饲粮中的适宜添加量.选择产奶量、泌乳日龄、胎次相近的荷斯坦泌乳奶牛48头,分为6组,每组8头,分别在饲粮中添加0（对照组）、15、30、75、150和300 g/d的CSH,预试期14d,正试期56 d,测定奶牛生产性能和血清激素水平.结果表明：奶牛的平均日采食量、平均日产奶量和4％标准乳产量在CSH添加量为75 g/d时最高,之后随着CSH添加量的升高而逐渐下降,且15～150 g/d组平均日采食量与对照组相比无显著差异（P＞0.05）,300 g/d组平均日采食量最低;乳脂率和乳总固形物含量在CSH添加量为75 g/d时最高,且其他试验组和对照组相比差异不显著（P＞0.05）;乳尿素氮含量随着CSH添加量的升高而逐渐下降,且添加量为300 g/d时最低.当CSH添加量为15 g/d时,血清生长激素和甲状腺素含量显著高于对照组（P＜0.05）,添加量为30 g/d时,血清生长激素和三碘甲状腺原氨酸含量显著高于对照组（P＜0.05）.综上所述,在中国荷斯坦奶牛饲粮中CSH的添加量以15～ 75 g/d为宜.

The objective of this study was to determine the optimal supplemental level of cysteamine hydrochloride （CSH） in diets for lactating Holstein dairy cows.Forty-eight healthy Holstein dairy cows,similarly in milk yield,days in lactation and parity,were allocated into six groups in a randomized complete block design with eight cows per group.Cows were supplemented with CSH at 0 （control group）,15,30,75,150 and 300 g/d in the basal diet.The pre-experimental period lasted for 14 days,and the experimental period lasted for 56 days.The performance and serum hormone levels of cows were detected.The results showed that average daily feed intake （ADFI）,average daily milk production and 4％ fat corrected milk yield were the highest when supplemented with 75 g/d CSH,then those indices were decreased with the increase of CSH supplemental level,while there was no significant difference in ADFI between 15 to 150 g/d groups and control group （P＞0.05）,and 300 g/d group had the lowest ADFI; milk fat percentage and milk total solids content were the highest when supplemented with 75 g/d CSH,and there were no significant differences between other experimental groups and control group （P＞0.05） ; milk urea nitrogen content was decreased with the increase of CSH supplemental level,and 300 g/d group was the lowest.When supplemented with 15 g/d CSH,serum growth hormone （GH） and thyroxine contents were significantly higher than those in the control group （P＜ 0.05） ; and when supplemented with 30 g/d CSH,serum GH and triiodothyronine contents were significantly higher than those in control group （P＜0.05）.In conclusion,the optimal supplemental level of CSH for Chinese Holston dairy cows is 15 to 75 g/d.