培育方式对和牛犊牛健康及生长发育的影响

本试验旨在研究在寒冷地区不同培育方式对和牛犊牛健康及生长发育的影响。选取20头健康、初生的和牛犊牛,采用单因素随机分组设计,分为2组。对照组采用母牛带犊自然哺乳方式培育犊牛,试验组采用人工哺乳方式培育犊牛。试验期为180 d,定期测定犊牛体重和体尺指标,观察犊牛健康状况。结果显示,犊牛在3月龄断奶时,试验组犊牛断奶体重及日增重显著高于对照组（P<0.05）;试验组6月龄时体重及日增重显著高于对照组（P<0.05）;对照组犊牛粪便指数、腹泻率、腹泻频率及死亡率均高于试验组的犊牛,其中腹泻率与腹泻频率两组间差异显著（P<0.05）。对照组犊牛呼吸系统疾病发病率、发病频率及死亡率也均高于试验组犊牛,且均差异显著（P<0.05）。结果提示,人工饲养培育和牛犊牛提高了和牛犊牛成活率,降低了犊牛腹泻和犊牛呼吸道疾病等的发病率,可充分发挥提高犊牛断奶体重的潜力,不仅降低了养殖和牛的经济成本,也提高优质肉牛的经济效益。     

复合微生态制剂对犊牛生长性能、粪样微生物和血液指标的影响

旨在研究复合微生态制剂对犊牛生长性能、粪样微生物数量、腹泻率和血清指标的影响。选取3~5月龄犊牛20头,按性别、体重基本一致的原则将犊牛分为对照组和试验组,每组10头犊牛,对照组犊牛饲喂基础日粮,试验组犊牛基础日粮中添加含有酿酒酵母菌、枯草芽胞杆菌和乳酸菌的复合微生态制剂,饲喂试验共30d。记录犊牛在试验开始和结束时的体重,计算并比较2组犊牛在试验期间的总增重和平均日增重;分别收集犊牛在试验开始和结束时的粪便样本,检测并比较2组犊牛在饲喂试验前后的粪样微生物数量;记录2组犊牛在试验期间的腹泻情况,计算并比较2组犊牛的腹泻率;试验结束时采集犊牛的血液样本,测定并比较2组犊牛的主要血液指标。结果表明,饲粮中添加复合微生态制剂对犊牛生长性能无显著影响(P>0.05);饲喂复合微生态制剂的犊牛粪样中乳酸菌的数量显著高于对照组(P<0.05),粪样乳酸菌数达到2.28×10^7CFU/g,试验组犊牛粪样中大肠菌群的数量显著低于对照组(P<0.05),且犊牛腹泻率也低于对照组;试验组犊牛的血清生化指标与对照组相比均无显著差异(P>0.05)。综上所述,饲粮中添加复合微生态制剂能有效改善犊牛肠道菌群并且降低犊牛的腹泻率。     

Effect of Pasteurized Colostrum on Growth Performance and Development of Gastrointestinal Tract of Calves

The effects of pasteurized colostrum on growth performance and development of the gastrointestinal tract of calves were studied in this test. Twenty healthy newborn Holstein calves with similar body weight were randomly divided into two groups. The calves in control group were fed non-pasteurized colostrum while that in experimental group were fed on pasteurized colostrum. The experiment lasted for 90 days. The body weight,average body gain (ADG),average daily feed intake (ADFI),F/G and diarrhea rate were determined and at 0,30,60 and 90 days old,the body indexes were measured. The results showed that compared with control group,the ADFI and ADG of calves at 90 days old in experimental group were increased 1.74% and 2.33% (P> 0.05),and cannon circumference and body length were increased 2.68% and 1.41% (P> 0.05),while the diarrhea rate and F/G were decreased 0.67% and 2.40% (P> 0.05).There was no significant effect of pasteurized colostrum on the complex stomach weight,small intestine weight and small intestine length (P> 0.05). However,the ratio of complex stomach weight to body weight in control group was significantly higher than that of experimental group (P< 0.05). In conlusion,the pasteurized colostrum had a positive impact on growth performance for calves in 90 days old.     

巴氏初乳对犊牛生长性能及胃肠道发育的影响

试验旨在研究初乳巴氏杀菌与否对犊牛生长性能及胃肠道发育的影响。选取体重相近、健康状况良好的20头新生荷斯坦牛犊牛,随机分为2组,对照组犊牛饲喂未经过巴氏杀菌的初乳,试验组犊牛饲喂经过巴氏杀菌的初乳,试验期90 d。试验期间测量两组犊牛体重、平均日增重（ADG）、平均日采食量（ADFI）及料重比（F/G）,同时观察犊牛腹泻情况,在0、30、60及90日龄测量两组犊牛体尺指标。结果显示,在90日龄时,与对照组相比,试验组犊牛的平均日采食量和平均日增重分别增加了1.74%和2.33%（P> 0.05）,试验组犊牛管围和体斜长分别增加了2.68%和1.41%（P> 0.05）,而腹泻率和料重比却分别降低了0.67%和2.40%（P> 0.05）。初乳巴氏杀菌与否对犊牛复胃重、小肠重及小肠长度的影响不显著（P> 0.05）,但显著降低了犊牛复胃重与活体重比（P< 0.05）。综上所述,巴氏初乳对90日龄内犊牛的生长发育有一定促进作用。     

Effect of Different Carbohydrate Sources on Growth Performance,Body Size Indexes andNutrients Apparent Digestibility of Beef Calves

The objective of this study was to determine the effect of different carbohydrate sources on growth performance, body size indexes and nutrients apparent digestibility of beef calves. Twenty newborn Black Angus calves were randomly divided into 4 treatments,5 replications per treatment and 1 calve per replication. The calves in control group fed with milk,while that of groups A,B and C fed with glucose,whey powder and ripened corn powder as the main carbohydrate source of milk replacer,respectively. The test was start when the calves were 30 days of age,and the trial period lasted for 45 days. The body weight and body indexes of calves were measured at 30,45,60 and 75 days of age. Two digestion tests were arranged at 35-43 and 65-73 days of age,in addition,the incidence of diarrhea was documented daily. The results showed that the effect of different carbohydrate source on the calves was obvious in the first period. At 30-45 days of age,the average daily gain of group C was extremely significantly lower than that of control group (P< 0.01),and significant lower than groups A and B (P< 0.05),while that of group A was significantly lower than that of control group and group B (P< 0.05).The DM apparent digestibility rate of group C was significantly lower than that of groups A and B (P< 0.05),the apparent digestibility of CP was significantly lower than that of group A (P< 0.05) and extremely significantly lower than that of group B (P< 0.01),diarrhea rate was also high in this period. After 45 days of age,this influence decreased,the average daily gain of groups A and B began to increase,and there was no significant difference compared with control group (P> 0.05). The growth rate of group C increased rapidly,and there was no significant difference of average daily gain compared with group A at 75 days of age (P> 0.05).The nutrient apparent digestibility were improved in the second digestible test,and the diarrhea rate began to decrease which was 0 at the end of the test. During the whole experiment,the different carbohydrate source had little effect on the body indexes. In conclusion,whey powder showed the best effects in the experiment,flowed by glucose and the effect of ripened corn powder was poor in the early,but it became better with the increase of calves' age.     

新疆褐牛犊牛补饲试验效果分析

[目的]为探讨新疆褐牛犊牛补饲对其生长发育以及经济效益的影响,[方法]试验选取新疆褐牛犊牛20头,分为试验组和对照组,试验组犊牛在哺乳的基础上补饲精料,4月龄断奶,对照组分阶段饲喂,6月龄断奶。同时测定4月龄、6月龄的体高、体斜长、胸围、管围、体重并计算日增重和经济效益。[结果]结果表明,与对照组相比,4月龄试验组在体高、体斜长有着明显的提高,6月龄试验组在体斜长、胸围、管围、体重和日增重也有着明显的提高,但均为达到显著水平(P0.05)。经济效益分析结果表明,通过犊牛早期补饲可明显提高农牧民收入,节约饲养成本,相比传统饲喂方式每头犊牛饲养至6月龄可节约成本342元。[结论]综上,早期补饲对可提高新疆褐牛犊牛的生长性能,对改善养殖经济效益,提高经济收入有着显著的效果。     

初乳饲喂次数对娟姗犊牛生产性能的影响

为研究探讨初乳饲喂次数对娟姗犊牛生产性能的影响,试验选取初生重接近的健康娟姗犊牛20 头,随机分为4 组,分别为对照组、试验I组、II组和III组,每组5 头犊牛,试验期为60 天。4 组犊牛出生当日饲喂两次初乳,首次初乳量按照体重的10.0%进行灌服,第2次初乳于出生后6~8 h按照体重的5.0%进行饲喂。4 组犊牛出生当日在产房饲养,2日龄时均转为室外犊牛岛单栏饲养。2日龄后,对照组每天上午06:00和下午16:00时各饲喂常乳1次,2~6日龄每次饲喂1.50 L,7~20日龄每次饲喂1.80 L,21~35日龄每次饲喂2.50 L,36~60日龄每次饲喂3.00 L,自7日龄开始犊牛自由采食颗粒料。试验Ⅰ组、Ⅱ组、Ⅲ组分别继续饲喂初乳至犊牛2日龄、4日龄、6日龄后再饲喂常乳,饲喂时间和饲喂量与对照组一致。结果表明:(1)在饲喂初乳后48 h、72 h、96 h,试验组与对照组犊牛血清免疫球蛋白g(IgG)均差异显著(p<0.05),120 h、144 h、168 h,试验Ⅰ组与对照组比较,犊牛血清IgG含量差异不显著(p>0.05),试验Ⅱ组、Ⅲ组血清IgG含量与对照组相比,差异极显著(p<0.01)。(2)随着初乳饲喂次数的增加,可有效降低犊牛20日龄内腹泻发生率,试验Ⅰ组、Ⅱ组、Ⅲ组较对照组比较犊牛腹泻发生率分别降低9.5%、22.5%、36.5%,治疗犊牛腹泻总成本较对照组分别下降12.0 元、43.2 元、76.8 元,3 组试验组犊牛成活率为100.0%。(3)初乳饲喂次数的增加,使0~60日龄娟姗犊牛平均日增重(ADG)升高,试验组与对照组相比较,日增重均差异极显著(p<0.01),分别增加16.7 g、33.3 g、80.0 g。试验Ⅱ组、Ⅲ组较试验Ⅰ组ADG差异也极显著(p<0.01)。综合考虑,建议娟姗犊牛饲喂初乳至6日龄,可降低犊牛腹泻发生率、减少治疗费用,提高犊牛成活率及ADG。     

不同糖源对肉用犊牛生长性能、体尺指数及营养物质表观消化率的影响

试验旨在研究不同糖源代乳料对肉用犊牛生长性能、体尺指数及营养物质消化率的影响。选取20头新生黑安格斯犊牛,随机分为4组,每组5头。对照组随母牛饲喂,A、B、C组分别饲喂以葡萄糖、乳清粉和熟化玉米粉为主要糖源的代乳粉,30日龄时开始正式试验,试验期为45 d。分别在犊牛30、45、60、75日龄时进行空腹称重,测量体尺,每天观察记录犊牛的腹泻情况。在35~43和65~73日龄进行两期消化试验,采集样品,测定表观消化率。结果显示,试验前期不同糖源对各试验组犊牛影响明显,30~45日龄时C组平均日增重显著低于A、B组（P< 0.05）,并极显著低于对照组（P< 0.01）,A组日增重显著低于对照组和B组（P< 0.05）;C组DM表观消化率显著低于A、B组（P< 0.05）;CP表观消化率显著低于A组（P< 0.05）,极显著低于B组（P< 0.01）;犊牛腹泻率在这一时期也偏高。45日龄后这种影响逐渐减小,A、B组犊牛日增重开始增加,与对照组差异不显著（P> 0.05）,C组犊牛生长速度也快速增加,到75日龄时平均日增重与A组差异不显著（P> 0.05）;第二期消化试验中各试验组犊牛营养物质的表观消化率均明显提高,犊牛腹泻率也开始降低,试验后期降至为0。而在整个试验期不同糖源对各组的体尺及体尺指数影响不大。综上,在试验中乳糖效果最好,葡萄糖次之,熟化玉米粉则在前期效果不佳,但随着犊牛日龄的增加效果逐渐改善。     

不同营养水平代乳料对夏南牛犊牛生长发育的影响

[目的]通过补饲代乳料提高夏南牛犊牛生长发育速度,培育优质健康犊牛,实现犊牛早期断奶。[方法]犊牛随机挑选并随机分成2个组,试验组使用B配方的饲料,对照组使用A配方的饲料,两组牛分圈饲喂,犊牛与母牛隔离饲养。代乳颗粒料自由采食,采取少给、勤给、逐渐增多的饲喂方法。试验期内测量犊牛体尺、体重,观察不同代乳料的适口性,记录疾病发生种类、次数和频率。[结果]试验组比对照组平均日增重提高17.78%,但差异不显著(P>0.05)。试验组比对照组体高、体斜长、胸围3项体尺分别增加了0.67 cm,1.04 cm和2.05 cm,差异不显著(P>0.05)。腹泻发病率试验组23.08%,对照组22.22%,两组均没有发生其他疫病和死亡。[结论](1)A、B两种代乳颗粒料均可以取代代乳粉,作为夏南牛犊牛的补饲料。(2)较高营养水平的代乳颗粒料,可以提高夏南牛犊牛日增重。试验用代乳颗粒料优于犊牛精料补充料。(3)B配方的代乳颗粒料适口性较好。     

不同饲养模式对哺乳犊牛消化道形态学结构的影响

为了研究不同饲养模式对犊牛消化道形态学结构的影响,试验选择20头体重相近的荷斯坦哺乳犊牛,采用完全随机试验设计,将犊牛分为2组,分别为对照组和试验组,对照组喂颗粒精料+牛奶,试验组饲喂颗粒精料+牛奶+优质牧草。结果表明:对照组犊牛瘤胃乳头数量和长度显著高于试验组(P<0.05),瘤胃厚度低于试验组(P<0.05)。说明添加牛奶和精料可以促进犊牛的瘤胃乳头发育,而添加牛奶、精料和干草则可促进瘤胃容积和组织的发育。     

天然纤维浓缩物对犊牛生长发育的影响

为研究在牛奶（或液体代乳）中添加天然纤维浓缩物VITACEL对犊牛早期生长发育（体重、体高、体斜长、胸围、腹泻情况）的影响,选用6日龄荷斯坦母犊22头,依据出生日期、体重相近的原则随机分为2组,试验组在牛奶中添加1%天然纤维浓缩物VITACEL,试验期39d。结果表明,试验组的平均体重、日增重、体高、体斜长和胸围在试验结束时均显著或极显著（P〈0.05或P〈0.01）高于对照组;试验组犊牛的腹泻率比对照组降低48.03%。     

呼伦贝尔短尾羊产前补饲精喂对家畜个体特征及生产效益的影响

在内蒙古草原牧区,冬季对绵羊补饲精喂的研究具有重要的意义。为研究产羔前对母畜舍饲精料后,呼伦贝尔短尾羊体重、体尺及经济效益的变化,本研究选取60对待产的呼伦贝尔短尾母绵羊作为试验对象,在母畜产羔前一个月,试验组母畜舍饲精料,对照组仅补饲干草,分析100日龄内家畜体重、体尺及经济效益变化。利用方差及偏最小二乘回归法,分析产前补饲对家畜个体、生产效益的影响及影响家畜体重的主要体尺权重,结果显示,100 d时间段内,母畜体重呈先减少后增加的趋势;仔畜出生后一个月左右的时间段,试验组仔畜的胸围、胸宽、体高、胸深、体长和体斜长显著高于对照组(P<0.05)。影响呼伦贝尔短尾羊体重的主要体尺指标为:胸围、胸宽、体高和胸深,影响权重达到50%以上。补饲使得仔畜的成活率、出售价格显著高于未进行补饲的对照组(P<0.05)。通过补饲母畜不仅可以影响仔畜体重和体尺指标,而且对提高仔畜成活率和经济效益具有重要的作用,这为今后后备母羊的选育、家畜的精准淘汰提供了理论基础。     

Optimizing the growth and immune system of dairy calves by subdividing the pre-weaning period and providing different milk volumes for each stage

In systematically considering the advantages and disadvantages of complementarity in high or low milk feeding, novel milk feeding schemes involving altering the volume of supplied milk in different stages of the pre-weaning period but maintaining the total milk feeding volume were tested. Twenty-seven newborn male Holstein calves were selected and randomly assigned to 3 treatments. Calves in the control (CON) group were fed 7 L of milk daily from 4 to 66 d of age. Calves in the low-high (LH) group were fed 6 L of milk daily at the beginning, and then the daily feeding volume was later increased to 7 to 8 L of milk, which served as the early-period low-volume feeding group. The calves in the high-low (HL) group were fed 7 to 8 L daily at the beginning, and then the daily feeding volume was decreased to 6 L of milk, which served as the early-period high-volume feeding group. Then all calves were fed 3 L of milk daily from 67 to 70 d of age, weaned at 70 d of age, and then fed starter feed to 100 d of age. All calves had access to the starter feed from 15 to 100 d of age. The diarrheal condition of calves was recorded daily and the growth performance including the starter feed intake and body weight of calves was recorded at 70 and 100 d of age. Then, five 100-d-old calves from each treatment were sampled for measurement of plasma indices, ruminal morphology, and volatile fatty acids. When compared with the CON and LH groups, calves in the HL group exhibited a significantly increased body weight and lower diarrhoeal rate. When compared with the CON group, calves in the HL group exhibited a significantly increased average daily feed intake, ruminal epithelium papillae length, total volatile fatty acids, and percentages of propionate and butyrate. Moreover, the significantly increased plasma immunoglobulin G (IgG) content and a trend of decreased tumor necrosis factor-α (TNF-α) content (P = 0.083) were also identified in the HL group when compared with the CON group. Overall, the early-period high-volume feeding for calves produced greater body weight gain and a lower incidence of diarrhea.     

科尔沁肉牛早期补饲饲养模式试验研究

[目的]通过试验探究科尔沁肉牛犊牛最佳的饲养模式,为后续科尔沁肉牛早期补饲的推广和普及提供理论支持。[方法]选取体型相近,初生体重在34～50 kg之间健康的科尔沁肉牛犊牛60头,分为对照组、补饲组1、补饲组2,每组20头,补饲组按试验方案进行早期补饲,对照组按传统饲养模式饲养,对比6月龄各项数据及试验牛母牛产后发情情况,进行分析总结。[结果]补饲组与对照组相比,犊牛生长发育效果差异显著,试验母牛产后恢复明显加快,产后90 d内发情母牛占比显著提高。[结论]科尔沁肉牛犊牛早期补饲更利于犊牛后期生长发育,促进母牛早发情提高繁殖能力,结合数据分析得出早期补饲至6月龄是更为适合科尔沁肉牛犊牛的饲养模式。     

早期补饲对规模养殖条件下平凉红牛犊牛体重的影响

[目的]为了探索早期补饲对规模养殖条件下平凉红牛犊牛体重发育的影响,[方法]选取分娩日期接近的妊娠母牛18头,分为试验组和对照组,早期补饲试验组犊牛,分析各月龄体重数据。[结果]结果表明在规模化养殖条件下,与传统养殖方式相比,对平凉红牛犊牛采取早期补饲,犊牛在3月龄到6月龄时体重差异显著（P<0.05）。[结论]因此,在实际生产中应重视犊牛早期的隔栏补饲工作,有利于提高肥牛生产效率和经济效益。     

Effect of Different Addition Schemes of Mannan Oligosaccharide on Growth Performance,Fecal Microorganism and Serum Immune Indexes of Calves

This experiment was conducted to study the effects of mannan oligosaccharides with different adding schemes on growth performance, fecal microorganism and serum immune indexes of calves.Twenty newborn Holstein calves were randomly divided into 4 groups with 5 replicates per group.The claves in group Ⅰ（control group）were not fed the mannan oligosaccharide.The calves in group Ⅱ were fed 5 g mannan oligosaccharide added into the milk,and that of group Ⅲ were fed 5 g mannan oligosaccharide added into the starter diet while calves of group Ⅳ were fed 2.5 g mannan oligosaccharide added into the milk and the starter diet,respectively.The feeding trial lasted for 56 days.The results showed as follows:①During the whole experiment period,body length an body structure of calves had no significant difference between the groups（P>0.05).②During the whole experiment period,the average daily dry matter intake（ADMI）and average daily gain（ADG）in the experiment groups was higher than the control group,the F/G was lower than the control group,and group Ⅱ was the best of the three experiment groups.③On 21th day,the number of Bifidobacterium in feces of the calves in the group Ⅰ was significantly lower than that in other groups（P<0.05),and that of group Ⅱ was the highest;The number of E.coli in feces of the calves in the group Ⅰ was significantly higher than that in other groups（P<0.05),and the group Ⅱ was the lowest.On 56th day,the number of Bifidobacterium of experimental groups were higher than that of control group.The change of E.coli number of four groups were as the same as 21th day.④On 21th day,the serum IgA content of experimental groups were higher than group Ⅰ,and that of group Ⅱ were significantly increased（P<0.05);IgG had a similar change with the IgA;The serum IgM content of group Ⅳ was significantly higher than group Ⅰ（P<0.05), while that of group Ⅲ was lower than control group;On 56th day,the serum immune indexes of experimental groups were all higher than control group（P>0.05).In conclusion,adding mannan oligosaccharides could promote calf growth performance,gut health and immunity,while adding mannan oligosaccharide to milk had better effects.     

怀孕后期补饲浓缩料后对牦牛犊牛出生重的影响

[目的]为了增加高原生态环境下犊牦牛的初生重,提高犊牦牛成活率。[方法]本研究采取了在母牦牛怀孕后期补饲的方法,在怀孕后期,母牦牛自然放牧回圈后,每晚每头母牦牛补饲250g母牦牛浓缩精料补充料,连续补饲3个月。[结果]表明,试验组犊牦牛的初生重显著大于对照组(P0.01);而且母牦牛产后掉膘少,产后发情率高。[结论]对地处高海拔地区的自然放牧母牦牛围产期补饲母牦牛浓缩精料补充料后,能有效提高犊牦牛的初生重。     

含β-内酰胺类药物有抗奶对犊牛生长发育和血液免疫指标的影响

试验旨在研究饲喂含β-内酰胺类药物有抗奶对荷斯坦公犊牛生长发育和血液免疫指标的影响。选用3日龄、体重（42.64 kg±1.16 kg）相近的公犊牛18头,随机分为2组。对照组饲喂正常牛奶,试验组饲喂有抗奶,犊牛60日龄断奶,试验期为180 d。试验第10、20、30、40和50天分别采集正常牛奶和有抗奶,测定乳成分、大肠杆菌数和乳中抗生素含量。试验第30、60、90和180天逐头空腹称重,测量体尺,并计算平均日增重（ADG）。试验第7、15、30、60、90和180天于晨饲前对公犊牛空腹静脉采血,制备血清,测定血清免疫指标。结果显示：①试验牛场有抗奶中β-内酰胺类抗生素含量为268.65 μg/L,且有抗奶的乳蛋白含量、体细胞数（SCC）和大肠杆菌数显著高于正常牛奶（P<0.05）;②饲喂有抗奶显著降低公犊牛第30天时的体重和试验60 d内的ADG（P<0.05）,显著降低公犊牛第90天时的体长及第60和90天时的胸围（P<0.05）;③与对照组相比,试验组公犊牛IgA在第30、60和90天时显著升高（P<0.05）,IgM在第7天时显著升高（P<0.05）,IgG在第30和60天时显著升高（P<0.05）;IL-2和TNF-α在第15和30天时均显著升高（P<0.05）。结果提示,饲喂有抗奶明显降低犊牛哺乳前期日增重,且在一定程度上提高犊牛断奶前后的血清免疫指标水平。     

高寒地区中国荷斯坦犊牛早期断奶方案对犊牛生长发育、腹泻与培育成本的影响

[目的]研究高寒地区中国荷斯坦犊牛早期断奶方案的推广价值。[方法]选取1周内新生、体重相近的犊牛16头,采用对照的试验方法将16头犊牛随机分为试验组和对照组,每组8头。试验组为早期断奶方案,对照组为常规断奶流程,试验期为90 d。[结果]试验组在60日龄与90日龄的日增重均显著高于对照组（P〈0.05）。试验组90日龄增重显著高于对照组（P〈0.05）。对照组犊牛30日龄内腹泻发病率为100%,重复发病率为75%;试验组30日龄内腹泻发病率为50%,重复发病率为50%。试验组与对照组相比节约成本32.52%。[结论]高寒地区中国荷斯坦犊牛可实行早期断奶方案,且能够提高企业和养殖户的经济效益,具有较好的推广价值。     

暖季放牧补饲对新疆褐牛公犊日增重及其血液激素水平的影响

试验旨在研究暖季放牧加补饲对褐牛公犊生长过程中不同时期血清激素水平变化的影响。选取10月龄新疆褐牛公犊70头,分为对照组(放牧)和试验组(放牧加补饲),分别于0、30、60、90和120 d时,测定公犊体重,并采集血样进行生长激素(growth hormone,GH)、睾酮(testosterone,T)、胰岛素(insulin,INS)、生长抑制素(somatostatin,SS)、甲状腺素(T4)、三碘甲腺原氨酸(T3)及糖皮质激素(corticosteroid,CORT)含量的检测。结果表明,在试验全期,两组公犊牛血清中GH含量差异均不显著(P>0.05);在90 d时,试验组公犊牛血清中T含量显著高于对照组(P<0.05),30、60和120 d时,两组差异均不显著(P>0.05);在60和90 d时,试验组公犊牛血清T4含量极显著高于对照组(P<0.01);在30、60和120 d时,两组公犊牛T3含量差异均不显著(P>0.05),90 d时,试验组公犊牛血清T3含量显著高于对照组(P<0.05)。提示,暖季天然草场放牧新疆褐牛公犊为其补饲合理的蛋白质和能量等营养物质能极显著提高公犊牛的日增重(P<0.01)。