Influence Of Calf Milk Replacer Feeding Time On Growth Performance,Serum Biochemical,Immune-Related Indicators In Dairy Bull Calf

The experiment studied that different milk replacer feeding time on growth traits,serum biochemical,immune-related indicators in dairy bull calf,using a single factor completely randomized,healthy,disease-free 20 finished feeding colostrum(3~7d)of male calves,according to body weight divided into experimental group A,group B,group C and control groups,each group of five repeat.Group A,B,C group were fed milk replacer to 45 d,60 d,75 d,after fed to90 d,control group was fed milk replacer until 90 d.The heart girth,withers height,body length,and body length of all the calves were measured on 45,60,70 and 90 day-old before morning meal and calculates the corresponding weight gain.While recording food intake for each group of calves,the number of deaths and diarrhea.For each group of calves take jugular blood 10 ml,measured serum biochemical,immunity and hormone parameters.The results are as follows:1.Impact on performance: the effects of different calf milk replacer feeding time on production performance are different.The heart girth,withers height,body length,daily gain,and body length of all the calves increased with the age.The effect of control group> 60 days group>75 days group> 45 days group.Compared with the control group,every calf of milk replacer fed to75 days,60 days,45 days save feed 180 yuan,360 yuan,540 yuan,respectively.2.Impact on serum biochemical:milk calf replacer feeding time effected serum biochemical parameters were not significant(p> 0.05).The content of aspartate transaminase reduced by age.The AST of calves of milk replacer fed to 60 days lower than other test groups in the experiment.The Cerealthirdtransaminase(ALT)and alkaline phosphatase(AKP)content change in milk replacer feeding time;The ALT,AKP of calf of milk replacer fed to 60 days lower than other test groups at 90 days.The total protein and albumin increases with age,60 days group higher than other test groups at 90 days.The cholesterol levels were reduced with age,but the triglycerides were increased with age,and calfves of milk replacer fed to 60 days group lower than other test groups since 60 d.3.Impact on immune:each group serum CD4+ influence was not significant(p> 0.05),CD8+at 45 days were significantly different(p <0.05),other phases were not significant(p> 0.05).Milk replacer feeding 60 d can improve CD4+,but not CD8+.4.Impact on hormone parameters:each group serum hormone were not significant(p> 0.05).serum growth hormone,thyroid hormone of calves of milk replacer fed to 60 days significantly higher than other experimental groups at 90 d.In summary,the calf milk replacer feed calves can increase heart girth,withers height,body length,daily gain,and body length.changing serum biochemical parameters,promoting the body’s metabolism,enhancing the immune function,reducing the cost,which fed 60 d for the best effect.