异位酸对泌乳牛产奶性能和饲料消化率的影响

Effects of branched chain volatile fatty acids supplementation on milk performance and nutrient digestibility in dairy cows

为研究异位酸对泌乳牛采食量、产奶量、乳成分、日粮养分消化率和血液代谢产物的影响,选用48头荷斯坦泌乳牛,按随机区组设计分成4组(对照、LBFA、MBFA和HBFA组),分别在日粮中添加异位酸0、30、60和90 g/d,进行110 d的饲养试验和10 d的消化试验。结果显示,MBFA和HBFA组干物质采食量显著高于LBFA和对照组(P<0.05);各组奶牛体重变化差异不显著;MBFA和HBFA组产奶量和乳脂率显著高于对照组(P<0.05);异位酸添加组乳蛋白率显著高于对照组(P<0.05),饲料转化率显著低于对照组(P<0.05)。异位酸添加组干物质、有机物、蛋白质和中性洗涤纤维消化率显著高于对照组(P<0.05);MBFA和HBFA组酸性洗涤纤维消化率显著高于LBFA和对照组(P<0.05)。异位酸添加组血浆葡萄糖、总蛋白质、生长激素释放激素、生长激素和胰岛素样生长因子浓度显著高于对照组(P<0.05);各组游离脂肪酸浓度无显著差异;MBFA和HBFA组乙酰乙酸和β-羟丁酸浓度显著高于LBFA和对照组(P<0.05)。综上可知,异位酸提高了泌乳牛采食量、产奶量和饲料养分消化率;其最佳添加量为60 g/d。

The objective of the study was to evaluate the effects of branched chain volatile fatty acids(BFA)on dry matter intake,milk yield,milk components,nutrient digestibility and blood metabolites in dairy cows.Forty eight Chinese Holstein cows were assigned to one of four groups in a randomized block design.Four treatments were control,low BFA(LBFA),medium BFA(MBFA)and high BFA(HBFA)with 0,30,60 and 90 g BFA per cow per day.Experimental period was 110 days with 20 d of adaptation followed by 90 d of data collection.The results showed that dry matter intake was higher(P<0.05)for MBFA and HBFA than for LBFA and control.Body weight changes were similar among treatments.Milk yield and milk fat percentage were higher(P<0.05)for MBFA and HBFA than for control.Milk protein percentage was higher(P<0.05)and feed conversion rate was lower(P<0.05)for BFA supplementation than for control.Digestibility of dry matter,organic matter,crude protein and neutral detergent fibre were higher(P<0.05)for BFA supplementation than for control.Digestibility of acid detergent fibre was higher(P<0.05)for MBFA and HBFA than for LBFA and control.Serum concentrations of glucose,total protein,growth hormone releasing hormone,growth hormone and insulin like growth factor 1 were higher(P<0.05)for BFA supplementation than for control.Serum non-esterified fatty acid was similar among treatments.Serum acetoacetate andβ-hydroxybutyrate were higher(P<0.05)for MBFA and HBFA than for LBFA and control.These data indicated that supplementation of BFA increased feed intake,milk yield and feed nutrient digestibility,and the optimum supplemental dose of BFA was 60 g per cow per day.