A Study On Soy Protein In Place Of Partial Milk Protein In Calf Milk Replacers

In order to reduce the milk of rearing calf, decrease the cost and do not affect the growth of calves, the experiment was conducted to study the effects of different soy proteins on performance, nutrient apparent digestibility, blood biochemical parameter, growth of organs, change of VFA and NH₃-N, health condition and economic benefit, Eighteen Holstein calves were allocated to three groups randomly, the milk replacers (MR) which calves in A, B group were fed came from dehulled soybean meal (DSM), full fat soybean (FFS), the calves fed milk in C group. The results were:1 the soy protein had definitely impacted on early body weight and body measurement. The body weight and ADG were not significant during whole experiment(P>0. 05). At 365d, body weight in A, B were higher than C, heart girth in A, B, C was 157. 00, 155.33, 154.67cm respectively, circunference of canon bone, wither height, body lenth were similar.2 Soy protein can cause gut hypersensitivity reaction to calves before 36d, the small intestinal villi had partial atrophy and became shorter, which induced drawback of digestibility and assimilation. The height of small intestinal villi in A, B were 46. 31%, 56. 66% compared with C respectively, likewise, the CP digestibility in A, B (53. 75%, 54.95%) were significantly lower than C (89.07%) (P<0.05), N retention (52.67%, 54.16%) also significantly lower than C (88.22%) (P<0. 05). The height of small intestinal villi in A, B were 107. 17%, 94. 91% compared with C, indicated that after a transitional period, the unhealthy stimula of soy protein to small intestinal villi had almost disappeared.3 Soy protein probably had negative affection to liver before 36d. ALP, T-BIL, D-BIL, I-BIL, ALT, AST å’Œ Y-GT in A, B were higher than C, and ALP (173U/L) inB was significantly higher than C (P<0. 05).4 The intakes of forage in A, B, C were 811. 16kg , 743.27kg, 688.04 kg respectively,similarly,, volume of rumen + reticulum in A, B were larger than C (P>0. 05) at 96d, and were 17.02%, 14. 16% compared with C respectively, demonstrated that forage can effectively stimulate the rumen growth.5 The VFA fluctuated within 2. 32⁴. 13mmol/100ml at 46d, 66d, 96d, there was no obvious rule on VFA and the ratio between acetate, propionate, butyrate, and similar as NH₃—N, the difference was not significant(P>0. 05).6 The calves probablely have a trasitional period to adapt soy protein. During the trasitional period(7-36d), the frequency of diarrhea and soft feces in A was 27, and the diarrhea was more severe, that of B was least(12).7 Two of MR can reduce cost greatly, the cost of each calf in A, B were 51. 61%, 52. 78% compared with C, A was slightly superior than B, the economic benefit were respectable.8 From above all , It got best effect from calves fed MR from FFS.