饲粮中添加不同脂肪来源对围产后期奶牛生产性能和瘤胃发酵的影响

The effect of adding different fat products to the diet on the production performance and rumen fermentation of dairy cows in the late perinatal period

为研究脂肪来源对围产后期奶牛生产性能、瘤胃发酵、血液参数的影响,本试验选取胎次[(2.95±0.1)胎]、体况和上一胎次平均产奶量[(31.4±0.4)kg]相近的健康中国荷斯坦奶牛60头,采用完全随机试验设计,分为三组,每组20头奶牛,分别饲喂泌乳净能和粗蛋白质含量一致,但脂肪(酸)来源不同的日粮,三组分别为基础饲粮组(A组)、脂肪酸钙组(B组)、棕榈酸脂肪粉组(C组)。试验期为母牛分娩当天(0 d)至产后21 d。试验结果表明:(1)干物质采食量:除泌乳天数10~12 d干物质采食量,B组较其他两组有下降的趋势(P=0.06)外,其他各阶段B组奶牛的干物质采食量显著低于A组和C组(P<0.05),全期干物质采食量B组较A组和C组下降18.78%和14.56%(P<0.01)。(2)产奶量方面:整个试验期,B组产奶量均低于A组和C组(P<0.05),但A组和C组差异不显著(P>0.05),全期产奶量B组较A组和C组下降13.41%和12.48%(P<0.05)。(3)瘤胃发酵参数方面:血液β-羟丁酸浓度(BHBA)在产后7、14 d差异不显著(P>0.05),产后21 d C组奶牛血液BHBA浓度较A组和B组下降16.44%和25.96%(P<0.05),A组和B组差异不显著(P>0.05);血液非酯化脂肪酸(NEEF)浓度在产后7 d和14 d差异不显著(P>0.05),而在产后21 d C组较A组和B组下降31.49%和31.06%(P<0.05);总胆固醇(TC)、甘油三脂(TG)、葡萄糖(GLU)、胰岛素生长因子(IGF-1)、牛瘦素(Lep)、尿素氮(BUN)检测产后0、7、14、21 d组间差异不显著(P>0.05)。(4)血液肝脏指标代谢方面:在肝损代谢中谷丙转氨酶和谷草转氨酶虽然在产后0、7、21 d差异不显著(P>0.05),但是产后14 d谷丙转氨酶C组较A组和B组下降28.98%和35.32%(P<0.05),谷草转氨酶下降28.66%和10.62%(P<0.05)。A组和B组差异不显著。碱性磷酸酶、高密度脂蛋白胆固醇、低密度脂蛋白胆固醇产后0、7、14、21天差异不显著(P>0.05)。综上所述,在本试验条件下,饲粮中添加脂肪粉可提高围产后期奶牛采食量和产奶量,缓解奶牛体脂动员程度,提高血清GLU浓度,降低NEFA和BHBA浓度,缓解奶牛能量负平衡(NEB),并且效果好于脂肪酸钙组。

This experiment was conducted to study the effects of fat sources on production performance,rumen fermentation and blood parameters of dairy cows in late perinatal period.In this experiment,60 healthy Chinese Holstein cows with similar parity[(2.95±0.1)parity],body condition and average milk yield of the previous parity[(31.4±0.4)kg]were selected and divided into three groups by completely randomized experimental design.Each group had 20 cows.They were fed diets with the same net energy of lactation and crude protein content,but different sources of fat(acid).The three groups were basal diet group(group A),fatty acid calcium group(group B),palmitic acid fat powder(group C).The test period was from the day of delivery(0 d)to 21 d postpartum.The results showed that:(1)Dry matter intake:In addition to the dry matter intake of lactation days 10~12 d,the dry matter intake of group B was lower than that of the other two groups(P=0.06).The dry matter intake of group B was significantly lower than that of group A and group C(P<0.05).The dry matter intake of group B was 18.78%and 14.56%lower than that of group A and group C in the whole period(P<0.01).(2)Milk yield:During the whole trial period,the milk yield of group B was lower than that of group A and group C(P<0.05),and the milk yield of group B was 13.41%and 12.48%lower than that of group A and group C(P<0.05).(3)Rumen fermentation parameters:There was no significant difference in bloodβ-hydroxybutyrate concentration between 7 days and 14 days postpartum(P>0.05).The bloodβ-hydroxybutyrate concentration of group C was 16.44%and 25.96%lower than that of group A and group B on 21 days postpartum(P<0.05),while at 21 days after delivery,group C decreased by 31.49%and 31.06%compared with group A and group B(P<0.05)at 0 day,7 days and 21 days after delivery,but alanine aminotransferase in group C decreased by 28.98%and 35.32%(P<0.05)compared with group A and group B,glutamic oxalacetic transaminase decreased by 28.66%and 10.62%(P<0.05)at 14 days after delivery.There was no significant difference between group A and group B.There was no significant difference in alkaline phosphatase,high density lipoprotein cholesterol,low density lipoprotein cholesterol postpartum on 0,7,14,21 days(P>0.05).In conclusion,under the condition of this experiment,adding dietary fat powder could improve the feed intake and milk yield of dairy cows in the late perinatal period,alleviate the body fat mobilization of dairy cows,increase serum GLU concentration,reduce NEFA and BHBA concentration,alleviate NEB of dairy cows,and the effect was better than that of fatty acid calcium group.