Effects of supplemental feeding amino acids on growth and blood biochemical indices of lactating foals under grazing conditions
[Objective]The purpose of this experiment is to investigate the effects of amino acid supplementa-tion on lactating mares under grazing conditions with a view of promoting the growth and development of lactating foals and blood biochemical indexes by improving milk yield and milk quality,and providing reference for the healthy growth of lactating foals under the condition of female milking.[Methods]Twenty-four Yili mares with similar foaling date(May)and 30 days of lactation were selected.They were 7-9 years old with 4-5 parities.The average daily 8 h milking volume from foaling to 30 days was(2.79±0.02)kg.The average weight of the 24 foals was(71.36±14.3)kg,8 females and 16 males.According to the sex of the foals,24 foals were randomly divided into 4 groups with 6 mares(2 females and 4 males)in each group,which were control group,trial groupⅠ,trial groupⅡand trial groupⅢ,respectively.The foal groups were corresponding to the mares.Under the same grazing condi-tions(grazing time,drinking time,milking time and grazing pasture were the same),the control group was not fed any amino acid supplement,trial groupⅠwas fed lysine 40 g/(d·horse),+threonine 20 g/(d·horse),trial groupⅡwas fed lysine 60 g/(d·horse),+threonine 40 g/(d·horse).Test groupⅢwas supplemented with ly-sine 80 g/(d·horse)+threonine 60 g/(d·horse).The supplementary feeding experiment lasted for 120 days.[Results](1)In terms of body weight and body size,compared with the control group,trial groupⅠand trial groupⅡcould significantly increase the body weight at 60 days,body height at 60 days and 90 days,total increase,and body skew length at 30 days and 120 days of nursing foals increased by 8.37％,4.44％,4.27％,24.22％,5.31％,5.20％and 6.25％,4.05％,4.09％,22.14％,5.55％,6.22％(P<0.01),respectively.At the same time,experi-mental groupⅠcould significantly increase the breast circumference and total breast circumference of lactating foals at 60,90 and 120 days by 6.34％,9.38％,9.52％and 33.83％,respectively(P<0.05).Experimental groupⅢcould only significantly increase the body height at 60 days,chest circumference at 61-90 days and 91-120 days,which were increased by 3.53％(P<0.01),25.17％(P<0.05)and 21.26％(P<0.05),respectively.There were no significant differences in tube circumference related indexes between experimental groups and control group(P>0.05).(2)In terms of blood biochemical indicators,The levels of Glu,ALT,AST and ALP in the blood of nursing foals in experimental groups were significantly increased by 13.08％,33.91％,26.93％,6.19％,17.08％,38.18％,26.69％,9.43％and 13.08％,respectively,compared with the control group 12.02％,38.14％,18.38％,6.35％(P<0.01),meanwhile,The contents of TP,UA,T-Bil,γ-GT and Ca2+in blood of nursing foals in trial groupsⅠandⅡwere significantly increased by 6.19％,23.44％,29.89％,15.47％,15.02％and 15.02％,respectively 6.67％,31.18％,30.07％,20.02％,14.00％(P<0.01).[Conclusion]Supplementing lysine and threonine can signifi-cantly promote the growth of body weight and body size of lactating mares under grazing conditions,increase the con-tents of TP,ALB,GLB,Glu and Ca2+in blood of lactating mares,increase the activity of ALT,AST and ALP,thus promoting the growth and development of foals.Supplementation of 40-60 g/(d·horse)lysine and 20-40 g/(d·horse)threonine to lactating mares can promote the growth and development of foals and body health.
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万方数据
维普
