Effect Of VE Selenium-enriched Lick Bricks On Reproductive Performance And Production Performance Of Lactating Cows

This experiment was designed to study the effect of VE selenium-rich lick bricks on reproductive performance and performance of lactating cows.A total of 662 healthy Holstein lactating cows with similar parity,milk production and lactation days were selected and randomly divided into control group and experimental group.331 lactating cows in the control group were not supplemented with lick blocks;331 lactating cows in the experimental group were supplemented with VE selenium-rich licking bricks.The differences in litter size,milk yield and lactation days between the two groups of lactating cows were not significant by t-test(P>0.05).The results indicated that:(1)Effect of VE selenium-rich lick bricks on reproductive performance of lactating cows:From the day of estrus to day 14 of estrus,the differences in estradiol,luteinizing hormone,follicle stimulating hormone,and progesterone levels were not significant(P>0.05)in the test group compared to the control group;the differences in pregnancy rate and mean number of mating were not significant(P>0.05).(2)Effect of VE selenium-rich lick bricks on serum biochemical indexes of lactating cows:TP and IgG content,ALB,IgM and T4 content on days 31 and 60,with highly significant differences(P<0.01);the difference in IgA content was highly significant(P<0.01)on day 60 and significant(P<0.05)on day 31;T3 and blood selenium levels were highly significantly increased on day 31(P<0.01);the differences in serum VE levels on days 60 and 92 were highly significant(P<0.01);GSH-px activity was highly significant higher on day 0(P<0.01)and on day 31(P<0.05),and blood selenium levels on day 60 were significantly increased(P<0.05);the differences in the other periods of each index were not significant(P>0.05).(3)Effect of VE selenium-rich lick bricks on the performance of lactating cows:Milk yield and DMI were highly significant(P<0.01)higher throughout the period;milk selenium content was highly significant(P<0.01)different on day 31 and 60;urea nitrogen was significantly(P<0.05)different on day 31 and 60;milk VE content was significantly(P<0.05)different on day 60;abortion rate was highly significant(P<0.01)lower and the incidence of uterine infections were significantly lower(P<0.05);the differences in the other periods of each index were not significant(P>0.05).In summary,supplementation with VE selenium-rich lick bricks can increase pregnancy rate,reduce average breeding times and improve reproductive performance of lactating cows to a certain extent;it can significantly increase serum VE,serum selenium content and glutathione peroxidase activity and improve antioxidant capacity of the body;it can significantly increase TP,ALB,IgG,IgM,IgA and T3,T4 content and improve immune capacity of the body;it can significantly increase milk yield,DMI and milk selenium content,significantly reduce abortion rate,significantly reduce urea nitrogen content and the incidence of uterine infection and improve the health of the body.It can significantly increase milk yield,dry matter intake and milk selenium content,significantly reduce the abortion rate,significantly reduce the urea nitrogen content and the incidence of uterine infections,improve the health condition of the cow’s body,improve production performance,and thus improve breeding efficiency.