| The aim of this study was to investigate the effects of different proportions of whole corn silage,millet straw and Leymus chinensis combined diet fed in the dry cows during the first phase of the dry period on its performance,rumen fermentation and blood indexes in perinatal period.Forty-five healthy and well-constrained dry cows were selected according to the principle of weight,parity and expected date of birth(P>0.05).The cows were randomly divided into test group A,group B and group C,with fifteen replicates per group,one cow per replicate.The concentrates to roughage ratio of the groups was the same,and the roughage were fed with the ratio of whole corn silage,millet straw and Leymus chinensis at 24:30:30,24:45:15 and 24:60:0.The all test cattle were transferred to the perinatal herd 2 weeks before the calving,and the three test cows began to be fed the same diets in the pre-perinatal and post-perinatal period.The test period was 88 days.The results showed that:(1)dry matter intake(DMI)and cow body condition scoring(BCS): Compared with group C,the dry matter intake(DMI)in group B was increased by 17.25%(P<0.05),10.46%(P<0.05),7.79%(P<0.05)and 5.65%(P<0.05)respectively on the 21 st day before delivery,the 7th day after delivery,the 14 th day after delivery and the 21 st after delivery,respectively.There was no significant difference between group A and C(P> 0.05).On the 14 th day after delivery and the 21 st day after delivery,the BCS in group B was 6.60% higher than that of group C(P<0.05)and 9.06%(P<0.05).There was no significant difference between group A and group B(P>0.05).The calf birth weight and the quality of colostrum(IgG): There was no significant difference in the birth weight of calves in each experimental group(P>0.05).But compared with group C,group A had an increasing trend,the IgG content of colostrum in group A and B was 10.82%(P<0.01)and 18.07%(P<0.01),respectively.The difference between group A and group B was not significant in the IgG content of colostrum(P>0.05).milk performance: Compared with group C,the milk yield of group B increased by 9.00%(P<0.05),the rate of non-fat solids increased by 2.83%(P<0.05),and the milk protein rate increased by 10.59%(P<0.05),the lactose rate increased by 5.64%(P < 0.05).(2)Blood biochemical indicators: On the day of delivery and the 21 st days after delivery,the serum triglyceride in group B was significantly lower than that in group A and C(P<0.05),and the urea nitrogen was significantly lower than that in group C(P<0.05).There was no significant difference in urea nitrogen between group A and group B(P>0.05).Leptin in group B was 12.11%(P<0.05),9.37%(P<0.05)and 8.70%(P<0.05)higher than that in group C on 21 days,7 days and delivery day,respectively.NEFA in group B was 7.93%(P>0.05),24.20%(P<0.05)and 19.26%(P < 0.05)lower than that in group C on 21 days,7 days and delivery day,respectively.Compared with group C,the blood glucose in group B was significantly increased by 22.09%(P<0.05).There was no significant difference in insulin and insulin-like growth factor I between the two groups(P>0.05).)from 7 days before delivery to 21 days after delivery,serum blood glucose showed a continuous upward trend.At 21 days before calving,albumin in group B was significantly higher than in group C(P<0.05).There was no significant difference in total protein between groups(P>0.05).Day 7 before delivery,day 21 after delivery and day 21 after delivery,Albumin in group A and Bwas significantly higher than that in group C(P<0.05).On the day of calving,total protein in group B was significantly higher than those in group A and group C.At day 21 postpartum,total protein in group B was significantly higher than that in group C.AST and ALT in group B were significantly lower thanthat in group C(P<0.05).The AST in group B was significantly lower than that in group C(P<0.05).The ALT in group A and group B was significantly lower than that in group C(P<0.05).At day 21 postpartum,AST and ALT in group B were significantly lower than those in group A and C(P<0.05).There was no significant difference between group A and groupC(P>0.05).(5)Blood Immune Indicators:Compared with group C,IgA and IgG in group B increased by 20.28%(P<0.05)and 11.90%(P<0.05),respectively.On the 7th day before calving,compared with group C,IgA in group A and group B was increased by 18.28%(P<0.05)and 20.97(P<0.05),IgM in group B increased by 13.06%(P<0.05),and IgG in group B increased by 7.65%(P<0.05).On the day of delivery,IgA in group B was higher than group A and group C by 12.5%(P<0.05)and 21.15%(P<0.05),respectively.IgM in group A and B was higher than group C by 4.51%(P<0.05)and 29.10%(P<0.05),respectively.IgM in group B was 23.53% higher than that in group A.IgG in group A and B increased by 13.50%(P<0.05)and 18.78%(P<0.05)respectively compared with group C..IgG in group B was 14.90% higher than that in group A(P<0.05).At 21 days postpartum,IgM and IgG in group B were significantly higher than those in group A and C(P<0.05).(3)Apparent digestibility of nutrients: The apparent digestibility of crude protein in group B was significantly higher thanthose in group A and C(P<0.01),which was 9.4%(P<0.01)and 14.1% higher than those in group A and C,respectively(P<0.01).The apparent digestibility of ether extract,neutral detergent fiber,acid detergent fiber,calcium and phosphoruswas not significantly different between the groups(P>0.05).(4)Rumen fermentation index: There was no significant difference in rumen fluid pH between groups A,B and C(P>0.05),but compared with group B,both groups A and C showed an increasing trend.The rumen liquid ammonia nitrogen,microbial protein,acetic acid,butyric acid and total volatile fatty acids in the test group A,B and C were not significantly different(P>0.05),but the group B was higher than the other groups.Compared with the group C,the propionic acid concentration in the group B increased by 18.75%(P<0.05),but the value of acetic acid propionic acid decreased by 11.65%(P<0.05).The propionic acid in group A and group B and C was decreased.There was no significant difference in propionic acid concentration and acetic acid/propionic acid value between group A and group B and C(P>0.05).(8)Rumen microflora: Species observation index,Simpson index,Zhao index,ACE index,library coverage were not significantly different(P>0.05)among the groups.There were significant differences in Shannon index between group A and group B(P<0.05)and no significant changes compared with group C.There were no significant differences in Bacteroidetes,Firmicutes and Proteobacteria between the three groups(P>0.05),and group A and B showed a marked upward trend compared with group C.In conclusion,the appropriate combination of whole corn silage,millet straw and Leymus chinensis was 24:45:15,which can improve the performance of perinatal dairy cows,the apparent digestibility of nutrients,and improve the stability of the internal environment of rumen fermentation. |
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