Effects Of Diets With Different Nutritional Leves On The Weight Gain And Reproduction Of Breeding Cow And Calbes Growth And Development

According to the feeding standard of beef cattle(NY / t815 ? 2004),the diets with different nutrition levels were designed according to the nutritional requirements of the cows at different production stages,including gestation and lactation stages,with Simmental cattle and Angus cattle as experimental breeds,the effects of different nutrition levels on body weight gain,calving and birth weight of simmental pregnant cows,the effects of different nutrition levels during lactation on the growth and development of simmental cows,and the effects of different nutrition levels during lactation on the reproduction of Angus cows and the growth and breeding of calves were studied,through analyzing the data of cow weight change,reproduction and calf growth,the suitable nutrition level of diet in different production stages was determined to provide technical guidance for scientific feeding management of large-scale cow farm and increase breeding benefit.The findings are as follows:1.Considering the effects of dietary energy and protein levels on pregnancy weight gain,calving difficulty,calf birth weight and feeding cost of simmental cows,the optimal nutrition level of simmental cows during pregnancy was determined as follows: first stage: comprehensive net energy 26.05 MJ / D,crude protein 463.6 G / D,The second stage: Comprehensive Net energy 33.66 MJ / D,crude protein 671.03 G / d.2.Considering comprehensively the influence of dietary nutrition level on calf growth and development,and cow feeding costs,the appropriate nutritional level of Simmental cows during lactation is determined as follows: milk production 6.0 kg,dry matter 8.7 kg/d,comprehensive Net energy can be 41.24MJ/d,crude protein 959g/d.3.Considering comprehensively the impact of dietary nutrition level on weight gain,reproduction and calf growth and breeding of the cow industry,the appropriate nutritional level of the Angus cows during lactation is determined to be: milk production 3.0 kg,dry matter 9.57 kg /d,total digestible nutrients 60.69%,crude protein 8.95%.