摘要
本试验旨在研究饲粮添加不同类型及水平的过瘤胃脂肪对荷斯坦奶牛生产性能和乳中脂肪酸组成的影响。试验选用产奶量及分娩期相近的荷斯坦奶牛40头,按随机单位区组法将奶牛分为5组,第1组饲喂以全株玉米青贮、苜蓿干草及精补料组成的基础饲粮;第2组和第3组分别在基础饲粮中添加4%和5%的过瘤胃不饱和脂肪,第4组和第5组分别在基础饲粮中添加4%和5%的过瘤胃饱和脂肪,每组8头。试验包括7 d的预试期和60 d的正试期。结果表明:1)第5组的干物质、非纤维碳水化合物与粗蛋白质采食量均显著高于第2组和第3组(P<0.05),粗脂肪采食量极显著高于其他组(P<0.01),第1组和第5组的中性洗涤纤维采食量极显著高于第3组(P<0.01),显著高于第2组(P<0.05)。2)第1组的4%乳脂校正乳产量显著低于第2、4和5组(P<0.05),乳糖产量显著低于第4和5组(P<0.05),乳蛋白产量显著低于第3、4和5组(P<0.05),而体细胞数(SCC)则显著高于第3、4和5组(P<0.05)。第3组乳蛋白率极显著高于第1、2组(P<0.01)。3)第4组的血清谷草转氨酶活性极显著高于第2组和第5组(P<0.01),血清白蛋白含量显著低于其他各组(P<0.05);第3组血清低密度脂蛋白胆固醇含量显著高于第4组(P<0.05);第5组血清总胆固醇含量显著高于其他组(P<0.05)。4)第2组和第3组乳中总不饱和脂肪酸及总单不饱和脂肪酸含量极显著高于第5组(P<0.01),而总饱和脂肪酸含量显著低于第5组(P<0.05),共轭亚油酸含量显著高于第5组(P<0.05);第5组总多不饱和脂肪酸含量极显著高于第1组和第4组(P<0.01)。综上所述,奶牛饲粮中添加过瘤胃脂肪可以提高产奶量和乳蛋白率,降低乳中体细胞数,且添加过瘤胃不饱和脂肪可以显著提高乳中总不饱和脂肪酸、总单不饱和脂肪酸及共轭亚油酸的含量,有效改善乳品质。综合来看,以添加5%的过瘤胃不饱和脂肪对于泌乳盛期的奶牛效果最佳。
This experiment was conducted to investigate the effects of different types and supplemental levels of rumen-protected fat on performance and fatty acid composition of milk in Holstein dairy cows.Forty Holstein dairy cows in early lactation were selected and divided into 5 groups with 8 cows per group by random unit block according to parity,milk yield and days in milk.Group 1 was fed a basal diet consisting of whole corn silage,alfalfa hay and concentrate supplement.Groups 2 and 3 were supplemented with 4%and 5%rumenprotected unsaturated fat in the basal diet,respectively.Groups 4 and 5 were supplemented with 4%and 5%rumen-protected saturated fat in the basal diet,respectively.The experiment consisted of a pre-feeding period of 7 days and a trial period of 60 days.The results showed as follows:1)dry matter,non-fiber carbohydrates and crude protein intake in group 5 were significantly higher than those in groups 2 and 3(P<0.05),ether extract intake in group 5 was significantly higher than that in other groups(P<0.01),neutral detergent fiber intake in groups 1 and 5 was significantly higher than that in group 3(P<0.01),and was significantly higher than that in group 2(P<0.05).2)The 4%fat corrected milk yield in group 1 was significantly lower than that in groups 2,4 and 5(P<0.05),the milk lactose production was significantly lower than that in groups 4 and 5(P<0.05),the milk protein production was significantly lower than that in groups 3,4 and 5(P<0.05),and the somatic cell count was significantly higher than that in groups 3,4 and 5(P<0.05).The milk protein rate in group 3 was significantly higher than that in groups 1 and 2(P<0.01).3)The serum glutamic oxaloacetic transaminase activity in group 4 was significantly higher than that in groups 2 and 5(P<0.01),the albumin content was significantly lower than that in other groups(P<0.05);the low density lipoprotein cholesterol content was significantly higher than that in group 4(P<0.05);and total cholesterol content in group 5 was significantly higher than that in other groups(P<0.05).4)Total unsaturated and total monounsaturated fatty acid contents in groups 2 and 3 were significantly figher than those in group 5(P<0.01),total saturated fatty acid contents were significantly lower than those in group 5(P<0.05)and conjugated linoleic acid content was significantly higher than that in group 5(P<0.05);total polyunounsaturated fatty acid content in group 5 was significantly higher than that in groups 1 and 4(P<0.01).To sum up,the addition of rumen-protected fat in dairy diet can effectively improve the milk production and milk protein rate,reduce the somatic cell count,adding rumen-protected unsaturated fat can significantly increase the total unsaturated fatty acid,total monounsaturated fatty acid and conjugated linoleic acid contents in milk,and effectively improve the quality of milk.The addition of 5%rumen-protected unsaturated fat is the best for dairy cows.[Chinese Journal of Animal Nutrition,2022,34(3):1580-1591]
作者
许鹏
杨致玲
曹名玉
段增亮
马晓强
王苗苗
张拴林
刘强
郭刚
XU Peng;YANG Zhiling;CAO Mingyu;DUAN Zengliang;MA Xiaoqiang;WANG Miaomiao;ZHANG Shuanlin;LIU Qiang;GUO Gang(College of Animal Science,Shanxi Agricultural University,Taigu 030801,China)
出处
《动物营养学报》
CAS
CSCD
北大核心
2022年第3期1580-1591,共12页
CHINESE JOURNAL OF ANIMAL NUTRITION
基金
健康功能畜产品生产技术研究与应用(201703D211001-05-04)
山西省科技攻关项目(20140311022-2)
山西现代农业牛产业技术体系(19-05)。
