The Effect Of Feeding Condition On Growth Performance And Four Hormone Levels In Blood Of Veal Calves

In order to determine the effect of diets on their growth performance, 48 fall-born Holstein male calves (the distance of the date of their birth less than 10 days) were separated into 4 groups(Ⅰ,Ⅱ,Ⅲ,Ⅳ) and fed with exclusively milk, milk apposition with concentrated feed, milk replacer and exclusively concentrated feed respectively after weaned at their 1 months of age. Body measurement and body weight were recorded and blood samples were collected when they were 2, 3, 4, 5, 6 months of age. The shape indexes and daily gains in each month were calculated. The concentration of 3'-triiodothyronine(T3), tetraiodothyronine(T4), insulin(INS) and growth hormone(GH) in blood serum were determined by radio immune assay(RIA). The result showed that:1. The body weight of calves in groupⅠwere 94.83kg, 141.58kg, 162.33kg, 193.00kg and 245.50kg at the age of 2～6 months, and greater than groupⅢandⅣ(P<0.01); Mostly, the body height and other indicators of body size in groupⅠwere greater than groupⅢandⅣ(P<0.05 or P<0.01). It is implied that the calves fed with milk exclusively have the best growth state. Calves in groupⅢhad lower body weight than groupⅣand other groups at their age of 2～4 months(P<0.05), and had lower level body length, body length, heart girth, thurl width, rump length and ham girth than groupⅣ(P<0.05). At their age of 5 and 6 months all studied indicators of body size on groupⅢwere not different with groupⅣ(P>0.05), and some of indicators were not different compare with groupⅠandⅡ(P>0.05). Body weight when 1～2 months of age and average daily gain during the time from 1 to 2 months in groupⅢwere lower than that in other three groups. but at the periods of their age from 4 to 5 months and from 5 to 6 months, the average daily gain of groupⅠwere 0.95 kg/d and 1.35kg/d, and it not different compare with the average daily gain of 1.09kg/d and 1.39kg/d in groupⅠ(P>0.05), and greater than groupⅣ(P<0.05). It is implied that calves fed with milk replacer might be competent to be growing at the level of fed by milk exclusively.2. Trunk index in each group were not different (P>0.05). There was no different heart girth between each two groups when they are 6 months of age (P>0.05), no different chest-thurl width index, limb length index and cannon circumference index between groups when they are 5, 6 months of age, and rump height index were not different between groups when they are 4～6 months of age, and no difference between groups on buttocks point height index when they are 3～6 months of age.3. Body length index, chest-rump width index, trunk index and heart girth index rose with the increase of their age in month mainly during 2～6 months of age, and limb length index, bottocks point height index and rump height index were on the contrary. Rump width index declined and was lowest when they were 4 or 5 months of age. Chest width index fluctuated in an extent. As the increase of the age of calves in month, they were growing follow the low approximately that lengthening faster than heightening, and thickening faster than lengthening. At the period from their 2 to 6 months of age, the relative length of limb decreased gradually, and bone thinningzed relatively, and the growth of fore part of body was more intensively than rear part on height and width.4. In this research, body weight in 2 months of age is related with level body length, ham girth and body length and hearth girth, etc. The indicator most related with body weight at 3 months of age is ham girth, the second and the third one is thurl width and hearth girth respectively. There are heart girth, body length, ham girth have a high correlation coefficient with body weight at their 4 months of age. At their 5 months of age, the most related indicator with body weight is ham girth. And at 6 months of age, the correlation coefficient of body weight with body height, height at hip cross, and ham girth are great relatively. Ham girth contributes the heaviest to the first principal component at the age of 2, 3, 5 mongths. And body weight contributes the heaviest to the first principal component at the age of 4, 6 mongths. From the age of 2 to 6 months, the heaviest contributors onto the second principal component are circumference of cannonbone of calves, average gain, heart girth, hip width, and average daily gain. As the result of analysis of variance of the fist principal component at each month of age, the value of the first principal component in groupⅠandⅡgreater than in groupⅢandⅣ(P<0.05). It is reasonable to regard the ham girth as an important indicator to the feed states and nutrition level of Holstein male calves.5. Body weight and all studied body size indicators are correlated with the T3 and GH level in serum very significantly (P<0.01). T3 level in serum is correlated with body length index, chest-thrul width index, chest width index, limb length index and heart girth index significantly (P<0.05 or P<0.01). GH level in serum is correlated with body length index, chest-thrul width index, chest width index, limb length index, heart girth index and buttock bones height index significantly (P<0.05 or P<0.01). T4 level in serum is correlated with level body length, body length, body length index, chest-thrul width index, heart girth index and rump width index significantly (P<0.05). INS level in serum is correlated with body length, heart girth, hip width, body length index, chest-thrul width index, chest width index, heart girth index and buttock bones height index significantly (P<0.05 or P<0.01). Calves in groupⅠhave the higher T3 level in serum than that of groupⅣat their age of 2～6 months (P<0.05), and except at 6 months of age, have higher T3 level than that of groupⅢ. GH level in serum is the same as each groups at their age of 2～6 months (P>0.05). The T3 level in serum may be an important signal of the status of growth performance and nutrition in veal calves.