饱和脂肪酸对泌乳中期热应激奶牛血液CO2、离子浓度和离子平衡的影响

选择产后150~210 d的中国荷斯坦奶牛48头,根据产奶量、分娩时间和胎次分为对照组(SFA0)、1.5%(SFA1.5)和3.0%(SFA3)饱和脂肪酸试验组,来研究饱和脂肪酸对高温环境条件下泌乳中期奶牛血液CO₂、离子浓度和离子平衡的影响,旨在为合理利用饱和脂肪酸及其缓解奶牛热应激提供理论依据。结果表明,日粮添加饱和脂肪酸,奶牛血清中CO₂的平均含量对照组、1.5%饱和脂肪酸组和3%饱和脂肪酸组分别为20.92,21.82和21.31 mmol/L,1.5%饱和脂肪酸组显著高于对照组(P<0.05),日粮添加饱和脂肪酸对热应激奶牛血液K、Na、Cl、Ca离子和离子平衡无显著影响,日粮添加饱和脂肪酸显著提高产奶量、乳脂和干物质含量(P<0.05)。说明饱和脂肪酸具有改善热应激奶牛生产性能,缓解热应激奶牛血液CO₂下降的作用。

Effect of supplemental saturated fatty acids on blood CO2, ions concentration and cation-anion balance of mid-lactating dairy cows during heat stress

The objective of this study was to investigate the effect of supplemental saturated fatty acids on blood CO₂, ions concentration and cation-anion balance of mid-lactating dairy cows under heat stress. Forty eight Chinese Holstein cows (150-210 days) were divided into three groups according to random block design with milk yield, DIM (days in milking) and parity. The animals were fed with diets contained 0, 1.5% and 3.0% saturated fatty acid for group 1(control), group 2(SFA1.5) and group 3(SFA3.0), respectively. The minimum THI (temperature-humidity index) was normally more than 72 during experimental period. Blood CO₂ concentration was 20.92, 21.82 and 21.31 mmol/L in cows fed with control, SFA1.5 and SFA3 diet, respectively. The blood CO₂ concentration was higher in SFA1.5 cows than control (P<0.05). There were no effects of treatment on ions concentration and cation-anion. The milk yield, milk fat content and total solid were improved by supplemental saturated fatty acid (P<0.05). In summary, supplemental saturated fatty acids improved milk yield and milk components and lessened blood CO₂ concentration decrease in mid-lactation heat-stressed dairy cows.