动物营养学报Issue(1)：103-111,9.DOI:10.3969/j.issn.1006-267x.2015.01.014
饲粮能量水平对热应激奶牛营养物质表观消化率及血液生化指标的影响
Effects of Dietary Energy Level on Nutrients Apparent Digestibility and Blood Biochemical Indices of Dairy Cows under Heat Stress
摘要
Abstract
In order to investigate the effects of dietary energy level on milk production, nutrients apparent di-gestibility and blood biochemical indices of dairy cows under heat stress, a single factor experimental design was used. Twenty-five healthy Chinese Holstein dairy cows in mid-lactation were allocated to 5 groups ( 5 cows in each group) corresponding to 5 isonitrogenous dietary treatments with net energy levels [ net energy for lac-tation (NEL), dry matter basis] of 6.15 (group 1), 6.36 (group 2), 6.64 (group 3), 6.95 (group 4) and 7.36 MJ/kg ( group 5) , respectively. The experiment lasted for 45 days, including a 15-day pre-experimental period followed by a 30-day experimental period. The results showed as follows: 1) the improving of dietary energy level reduced respiratory frequency, groups 4 and 5 were extremely significantly lower than groups 1 and 2 ( P<0.01) , and had no significant difference compared with group 3 ( P>0.05) . 2) There was a signifi-cant negative correlation between dry matter intake and dietary energy level (R2=0.983 3, P=0.017), and group 5 was significantly lower than the other groups (P<0.05 or P<0.01); milk yield in group 4 was the highest, and was increased by 9% compared with that in group 1 ( group 1 had the lowest value) , the differ-ence was extramely significant ( P<0.01) . 3) Apparent digestibility of nutrients ( excepted calcium, phosphor-us and gross energy) reached the maximum in group 1 and the minimum in group 5, the differences were sig-nificant or extramely significant ( P<0.05 or P<0.01) . 4) In group 4, serum cortisol concentration was signifi-cantly or extramely significantly lower than that in groups 1, 2 and 5 (P<0.05 or P<0.01), serum lipopo-lysaccharide concentration was significantly or extramely significantly lower than that in the other groups ( P<0.05 or P<0.01) , and serum glucose concentration was significantly higher than that in groups 1 and 5 ( P<0.05); the activity of serum creatine kinase in groups 1 and 4 was significantly or extramely significantly high-er than that in groups 2, 3 and 5 ( P<0.05 or P<0.01) , and group 4 increased by 32.87% and 25.40% com-pared with groups 2 and 3, respectively; the activities of serum cereal third transaminase and aspertate amin-otransferase showed group 1>group 2>group 4>group 3>group 5. Comprehensive analysis on the effects of di-etary energy level on milk production, nutrients apparent digestibility and blood biochemical indices indicates that under conditions in the present study, the optimal dietary NEL level is 6. 95 MJ/kg of dairy cows under heat stress.关键词
能量水平/热应激/奶牛/表观消化率/血液生化指标Key words
energy level/heat stress/dairy cow/apparent digestibility/blood biochemical indices分类
农业科技引用本文复制引用
闫方权,薛白,达勒措,宋良荣,王立志,卜登攀..饲粮能量水平对热应激奶牛营养物质表观消化率及血液生化指标的影响[J].动物营养学报,2015,(1):103-111,9.基金项目
国家科技支撑计划(2012BAD12B02) （2012BAD12B02）
