Effects Of Different ?-carotene Supplementation On Reproductive Performance,hormones And Antioxidant Index Of Holstein Dairy Cows

With the improvement of milk production,the reproductive performance of dairy cows declined,which restricts the development of daily industry.How to improve the reproductive performance of dairy cows is one of the most important issues in the dairy industry.This paper was to study the effects of differnt amounts of ?-carotene on the production performance,hormones and antioxidant capacity of dairy cows,to provide scientific basis to improve the reproductive performance of dairy cows.Experiment 1 The effects of differnt ?-carotene supplementation on the reproductive performance of dairy cows.60 periparturient Holstein cows which had similar parity,body condition score and calving date were selected and divided into 3 groups.All cows were fed basal diet,and control group,group 1 and group 2 added respectively 0,200 and 400 mg/head/d ?-carotene during the postpartum 0?90 days,the effects of differet ?-carotene supplement on the productive performance of dairy cows were studied.The results showed that the addition 400mg/kg ?-carotene reduced the numbers of services per conception(P<0.05),shorten the first oestrus time,the first breeding time and empty pregnant period,increased the oestrun fecundation rates,reduced the incidence of postpartum reproductive disease(P>0.05).The effects of adding 400 mg/head/day ?-carotene were better than that adding 200 mg/head/day ?-carotene.Experiment 2 The effects of differnt ?-carotene supplementation on serum hormone concentrations of dairy cowsThe selection and groupingof experimental animal,experimental design and feeding management were same as the experiment 1,the effects of differet ?-carotene supplement on serum hormone concentrations of dairy cows were studied.The results showed that the addition P-carotene increased the concentration of progesterone in serum,but had no effect on the levels of FSH,LH and estradiol in serum(p>0.05).In the conclusions,the dairy cows of adding ?-carotene 200mg/head/day were higher levels of LH and estradiol in serum than that adding 400mg/head/day(p<0.05),the dairy cows of adding ?-carotene 200mg/head/day were also slightly higher levels of FSH and progesterone in serum than that of adding 400mg/head/day(p>0.05).Experiment 3 The effects of differet ?-carotene supplementation on antioxidant capacity of dairy cowsThe selection and groupingof experimental animal,experimental design and feeding management were same as the experiment 1,the effects of adding p-carotene on antioxidant capacity of dairy cows were studied.The results showed that,with the ?-carotene supplement increased,the serum levels of GSH-PX and SOD were raised,the serum levels of MDA were decreased,and the serum levels of T-AOC?GSH-PX of adding ?-carotene groups significantly higher than that no adding ?-carotene group(p<0.05).The serum levels of GSH-PX?SOD?MDA of groups of addition 400 mg/head/day?-carotene were higher than that of addition 200 mg/head/day(P>0.05),and the serum levels of T-AOC of adding 400 mg/head/day ?-carotene group was lower than of adding 200 mg/head/day(P>0.05).