| The purposeof based on the combination of the seasonal changes of Forage Nutrition in the grazing production system of WULAGAI grassland in Inner Mongolia and the balance of annual nutritional needs of beef cows for warm season grazing and cold season house feeding,the purpose of this study was to explore the effects of warm season grazing and cold season feed composition on the reproduction and growth performance of Huaxi cows grazing in WULAGAI grassland in three different pastoral areas,It is expected to clarify the precise nutrition and feed composition of grazing beef cows calves in WULAGAI grassland in different production cycles,so as to provide a scientific basis for improving the reproduction of grassland beef cows and the growth and development of calves,promoting the coupling of grass and livestock,and implementing the precise nutrition balance regulation.The results showed that:1 The breeding period of female cattle is divided into two stages: grazing period and house feeding period.Three different grazing areas(control group,trial group I and trial group II)were selected,with 20 weaned female calves in each group.The pre-test was carried out after grazing for 3 months.The positive test began with feeding total mixed ration(TMR)in the house feeding period in the cold season.According to the nutritional value and feed combination effect of natural hay and Artificial Forage in three different grazing areas,three TMRs with different feed composition were prepared to study the effects of three TMRs on growth performance,feed conversion efficiency,digestibility and blood biochemical indexes of heifers,the results show that the apparent digestibility of trial group I cows was significantly higher than that of the other two groups(P<0.05).There were significant differences in average dry gain,dry matter intake and body size between trial group I cows and the other two groups(P<0.05);During the house feeding period,the feed weight ratio of trial group I cows was significantly lower than that of the other two groups(P<0.05),the blood glucose content of trial group II cows was significantly lower than that of the other two groups(P<0.05),and the cholesterol content of trial group I cows was significantly lower than that of the other two groups(P<0.05).In conclusion,trial group I grazing forage and TMR can improve the feed conversion efficiency and blood immune function of cows in breeding period,and promote the growth and development of cows in breeding period.2 Cows were in the warm season grazing period of WULAGAI grassland during the whole pregnancy.Through the analysis of forage nutrients,in vitro rumen fermentation,mineral element content,cow growth and development,blood biochemical indexes and production performance in three different grazing areas.The results show that the nutritional value of grazing forages in trial group I was significantly higher than that of the other two groups(P<0.05),and the forages in trial group I were rich in mineral elements.The content of selenium was not detected in the forages in control group and trial group II.the gas production,dry matter and neutral detergenta fiber digestibility in trial group I were significantly higher than those in the other two groups(P<0.05),The concentrations of serum albumin and total protein in group ⅱ were higher than those in the other two groups(P<0.05),and there was no significant difference in the content of serum blood urea nitrogen among the three groups(P<0.05).In conclusion,the nutritional value of grazing forage in trial group I was higher than that in the other two groups.The mineral content could meet the nutritional needs of pregnant cows,reduce the loss of nitrogen,and improve the growth performance and production performance of pregnant cows.3 According to lactating cows nutritional needs and combined with the feed combination effect,three different TMRs were designed in three different grazing areas and their forage species.They were fed in the shed in the cold season and then grazing in the warm season.Through the analysis of the growth performance,reproductive performance,serum biochemical indexes and growth performance of calves,the results show that the first estrus time and conception rate of cows in trial group I were significantly higher than those in the other two groups(P<0.05).The concentration of serum cholesterol in the three groups during lactation was higher than that in other periods,and the concentration of albumin was significantly lower(P<0.05).There was no significant difference in various body size indexes of cows during lactation(P<0.05)The average dry gain of three-month old and weaned calves was significantly higher than that of the other two groups(P<0.05).In conclusion,cows have strong energy and protein metabolism during lactation.TMR in trial group I can shorten the postpartum interval of lactating cows,improve reproductive performance and increase the birth weight of calves.In conclusion,there are significant differences in the effects of Forages on the growth and development of cows in different grazing areas.The forages in trial group I can significantly improve the production performance of cows.Different feeding methods TMR had significant effects on the reproductive performance of cows.During the breeding period,the feeding methods of group I could improve average dry gain and dry matter intake and reduce the feed weight ratio.During lactation,the feeding method of group I can shorten the postpartum estrus time of lactating cows,improve the postpartum body condition of cows,shorten the fetal spacing,and improve the reproductive performance of cows in the next season.Appropriate feed combination can reduce the breeding cost of farmers and herdsmen and improve the production performance of beef breeding cows in grassland grazing system. |
