不同物理形态开食料对犊牛生长发育、瘤胃发酵及血液指标的影响

Effects of Starters in Different Physical Forms on Growth and Development,Rumen Fermentation and Blood Parameters of Dairy Calves

本试验在湿热条件下,探究饲喂不同物理形态的开食料对犊牛生长发育、瘤胃发酵及血液指标的影响。试验采用36头荷斯坦母犊牛,随机分为3组(每组12头),分别自由采食颗粒状开食料(PSA)、粉末状开食料(PSB)和多颗粒状开食料(TS)。试验期63 d,其中1~42日龄为正常饲喂牛奶时期(断奶前期);43~49日龄为断奶期;50~63日龄为断奶后期。开食料从犊牛5日龄开始自由采食。在1、42、49以及63日龄晨饲前进行采血和称重,49和63日龄晨饲前胃管法采集瘤胃液。试验期间每天记录采食量和温湿度指数。结果表明,在湿热环境下:1)断奶期和断奶后2周TS组开食料干物质采食量、平均日增重和重料比高于PSA和PSB组,PSB组最低,但差异不显著(P>0.05)。2)TS组犊牛初次反刍时间较PSA组提前3.8日龄,较PSB组提前4.7日龄,差异均显著(P<0.05)。63日龄时,TS组瘤胃液氨氮含量显著低于PSA组(P<0.05)。3)42日龄时PSA组犊牛血液免疫球蛋白G含量显著高于TS组(P<0.05)。4)TS组犊牛初始腹泻时间较PSA和PSB组分别晚0.44和1.75日龄,但无统计学差异(P>0.05),TS组腹泻率最低。综合得出,湿热环境下,多颗粒状开食料较颗粒状开食料和粉末状开食料更能促进犊牛的生长发育,使犊牛尽早产生反刍行为。

The objective of this study was to determine whether the physical forms of starters could influence growth and development, rumen fermentation and blood parameters of dairy calves under hygrothermal envi- ronment. Thirty-six Holstein female calves were randomly assigned to 1 of 3 groups with following starters differing in physical forms ： pelleted starter （ PSA group, n = 12）, fine powder starter （ PSB group, n = 12 ） and texturized starter （ TS group, n = 12 ）. The whole experiment lasted for 63 days with a 42-d milk feeding period （pre-weaning period）, a 6-d weaning period and a 14-d post-weaning period. Calves were fed starters since 5 days of age. At 1, 42, 49 and 63 days of age before morning feeding, blood sample was collected, and body weight was measured; at 49 and 63 days of age before morning feeding, rumen fluid was collected by the method of gastric canal. Feed intake and temperature-humidity index （THI） were recorded everyday. The re- suits showed that under hygrothermal environment： 1 ） at weaning period and after being fully weaned for 2 weeks, TS group had higher start dry matter intake, average daily gain and gain-to-feed ratio than PSA and PSB groups, and PSB group had the lowest values, but the differences were not significant （P〉0.05）. 2） Calves in TS group exhibited rumination behavior 3.8 days earlier than that in PSB group and 4.7 days earlier than that in PSA group （P〈 0.05 ）. TS group had a significantly lower ammonia nitrogen content than PSA group at 63 days of age （P〉0.05）. 3） PSA group had a significantly higher immunoglobulin G content than TS group at 42 days of age（P〈0.05）. 4） The initial diarrhea time of PSA and TS groups showed 0.44 and 1.75 days later than PSA and PSB groups, but there was no significant difference （P〉0.05）. It is concluded that under hygrothermal environment, compared with pelleted starter and fine powder starter, texturized starter can promote calf growth and development, early exhibition of rumination behavior, and complete of rumen function.