Effects Of Different Seasons And Vitamin Supplementation In Winter On Production Performance,Milk Quality And Antioxidant Performance Of Holstein Dairy Cows

Aiming at the effects of region,season and vitamin supplementation on production performance,milk quality and antioxidant index of dairy cows,the production performance and milk quality of Holstein dairy cows in different seasons during three years in Laiwu area were studied,and the effects of vitamin supplementation in winter on production performance,milk quality and antioxidant index of Holstein dairy cows were studied.The effects of different seasons on production performance and milk quality of Holstein dairy cows in Laiwu area were studied.Laiwu Jerry dairy farm was selected as the experimental animal.The milk performance and milk quality of Holstein dairy cows with similar parity and health were recorded for three years in 2016,2017 and 2018.From 2016 to2018,the number of lactating cows was 225,240 and 215,respectively.The different seasons in Laiwu area are divided into spring(March-May),summer(June-August),autumn(September-November)and winter(December-February)according to natural months.The results showed that:(1)the average monthly milk yield in summer of 2016-2018 was the highest and significantly higher than that in winter of the same year(p < 0.05),the lowest monthly milk yield in winter was not significantly different from that in autumn(p > 0.05);the total milk yield in different seasons of 2016-2018 showed a trend of first increasing,then decreasing and then increasing;(2)the milk yield of Holstein dairy cows in different seasons of Laiwu region from 2016 to 2018.The change rule of milk quality: milk fat rate in spring and winter of 2016 and 2017 was significantly higher than that in summer and autumn(p <0.05),milk fat rate in summer and autumn was not significantly different(p > 0.05),milk fat rate in winter of 2018 was significantly higher than that in summer and autumn(p < 0.05),milk fat rate in summer and autumn was not significantly different(p > 0.05).The milk protein rate in winter of 2016-2018 was significantly higher than that in spring,summer and autumn(p < 0.05);the effect of non-milk non-fat solids was significantly higher in winter of2017 and 2018 than that in spring,summer and autumn(p < 0.05);the effect of total bacterial count in milk was not significantly different between 2016 and 2018(p > 0.05),but in autumn of 2017 was significantly higher than that in spring and winter(p < 0.05).< There was no significant difference between summer and summer(p > 0.05).Effects of vitamin supplementation in winter on production performance,milk quality and antioxidant index of Holstein dairy cows.A total of 150 Holstein multiparous dairy cows(with 4-5 parities,body weight 650 ± 50 kg,lactation period 20 ± 3 weeks and healthy lactation period)were randomly divided into 5 treatments,each with 3 replicates and 10 replicates.Group I was the control group,fed basic diet(containing: vitamin A 4000 IU/kg,vitamin D 1500 IU/kg,vitamin E,10 mg/kg),group II was supplemented with vitamin A(VA)4500 IU/kg,group III was supplemented with vitamin D(VD)1500 IU/kg,group IV was supplemented with vitamin E(VE)10 mg/kg,group V was supplemented with basic diet.Compound B vitamins are added.The experimental period was 12 weeks.The results showed that:(1)Adding compound VB,VA and VD to the basic diet could increase milk production of dairy cows,and the milk production of dairy cows with compound VB in the basic diet was significantly higher than that of the basic diet formula,the basic diet with 4500 IU/kg VA and the basic diet with 10 mg/kg VE(p < 0.05);(2)Adding 4500 IU/kg VA to the basic diet,1500IU/kg to the basic diet and the basic diet with 1500 IU/kg VE(p < 0.05).The solid content of non-fat milk in the group with 10 mg/kg VE and the group with compound VB was significantly higher than that in the group with basic diet(p < 0.05),which increased by 0.1%,0.33%,0.31% and 0.36% respectively;the milk in the group with 4500 IU/kg VA,the group with 1500 IU/kg VD,the group with 10 mg/kg VE and the group with compound VB in the basic diet were finer than those in the group with basic diet(p < 0.05).The total cell count was significantly lower than that of the basal diet(p < 0.05),which decreased by 17.6million/mL,20.9 million/mL,21.9 million/mL and 32.7 million/mL,respectively.Increase VE in the diet to increase the milk fat rate.The addition of compound VB in the diet increased the freezing point value of milk.Increasing dietary vitamin level had no significant effect on milk acidity,protein rate and total bacterial count(p > 0.05).(3)The content of malondialdehyde(MDA)in milk and blood in the basal diet supplemented with 4500 IU/kg VA,1500 IU/kg VD,10 mg/kg VE and compound VB was significantly lower than that in the basal dietsupplemented with compound VB(p < 0.05),indicating that the increase of VA,VD,VE and compound VB in the diet could reduce the content of malondialdehyde(MDA)in milk and blood.The content of superoxide dismutase(SOD)in milk of 10 mg/kg VE group was significantly higher than that of 1500 IU/kg VD group and compound VB group(p < 0.05),indicating that the antioxidant effect of VE was better than that of VA,VD and compound VB group;4500 IU/kg VA group(group II)and 10 mg/kg VE group(group IV)were added to basic diet.The serum superoxide dismutase(SOD)content in group V with compound VB was significantly higher than that in group I with basic diet and group III with 1500IU/kg VD(p < 0.05),but there was no significant difference between group I with basic diet and group III with 1500IU/kg VD(p > 0.05).The levels of glutathione peroxidase(GSH-Px)in milk of1500 IU/kg VD group and 10 mg/kg VE group were significantly higher than those of basal diet group(p < 0.05),and increased by 13.68 U/ml,15.46 U/ml and 18.67 U/ml,respectively.The basal diet supplemented with compound VB group was higher than basal diet group,but the difference was not significant(p > 0.05);the basal diet supplemented with 10 mg/kg VE group(group IV)cows.The highest activity of serum glutathione peroxidase(GSH-Px)was115.08 U/ml,which was significantly higher than that of basal diet group(group I),basal diet supplemented with 4500IU/kg VA(group II),basal diet supplemented with 1500IU/kg VD(group III)and basal diet supplemented with compound VB(group V)(p < 0.05),which were66.99 U/ml,55.94 U/ml,63.67 U/ml,52.42 U/ml,respectively.The activity of glutathione peroxidase(GSH-Px)in serum of dairy cows fed 1500IU/kg VD group(group III)was higher than that of basal diet group(group I),but the difference was not significant(p > 0.05).