摘要: |
为研究去势和热应激对筠连黄牛生产性能、瘤胃发酵和血液生化指标的影响,本研究选用18头16月龄、体重相近((292.35±28.71) kg)的不同去势程度筠连黄牛(全去势FCG、半去势HCG、假手术SOG),分为3组,每组6个重复,每个重复1头牛,根据试验期间牛舍温湿度指数(THI),分为热应激期(7、8月)和非热应激期(9月),分析去势和热应激对黄牛各指标的影响。结果表明:1)与非热应激期相比,热应激期牛舍THI、肉牛呼吸频率和直肠温度均显著提高(P<0.05)。2)去势和热应激均显著提高血清热休克蛋白70、高密度脂蛋白(HDL-C)、低密度脂蛋白(LDL-C)和雌二醇浓度(P<0.05),而睾酮、甲状腺素(T4)、胰岛素和游离脂肪酸浓度显著降低(P<0.05),且除血清葡萄糖、T4和LDL-C外,去势和热应激对其他血清指标存在显著互作效应(P<0.05)。3)全去势和热应激均显著降低肉牛平均日增重(ADG),且存在显著互作效应(P<0.05)。4)热应激期,去势显著降低粗蛋白、酸性洗涤纤维和钙表观消化率以及血清总抗氧化能力(T-AOC)(P<0.05),而热应激消除后,去势显著提高了T-AOC含量(P<0.05)。5)去势和热应激均显著提高瘤胃pH(P<0.05),显著降低氨态氮(NH3-N)、乙酸(AA)和总挥发性脂肪酸(TVFA)浓度(P<0.05),且去势和热应激对瘤胃pH、NH3-N、AA和TVFA浓度存在显著互作效应(P<0.05)。综上,公牛去势和热应激均会影响机体性激素分泌和养分表观消化率,从而降低生产性能,为热应激期肉牛饲养管理提供科学依据。 |
关键词: 筠连黄牛 热应激 去势 生产性能 表观消化率 血液生化指标 |
DOI:10.11841/j.issn.1007-4333.2024.01.12 |
分类号:S823 |
基金项目:四川省科技计划项目(2021YFYZ0001);财政部和农业农村部:国家现代农业(肉牛牦牛)产业技术体系项目(CARS-37);临沧市肉牛改良与产业化发展关键技术研究与示范项目(202104AC100001-A04) |
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Effects of castration and heat-stress on production performance, rumen fermentation and blood biochemical indexes of Junlian cattle |
YUE Ziqi1, YAO Xiaohe1, WANG Zhisheng1*, HU Rui1, ZOU Huawei1, XIAO Jianxin1, ZUO Zhicai2, PENG Quanhui1, LIANG Xiurong1, DENG Wensong3, WANG Cheng4, ZUO Jiaxue5
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1.Key Laboratory of University in Cattle Low Carbon Breeding and Safety Production in Sichuan Province/Animal Nutrition Institute, Sichuan Agricultural University, Chengdu 611130, China;2.College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China;3.Junlian County Agricultural and Rural Department, Yibin 645250, China;4.Junlian County Animal Husbandry and Fisheries Service Center, Yibin 645250, China;5.Lincang Animal Husbandry and Veterinary Technology Promotion Center, Lincang 677099, China
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Abstract: |
The purpose of this study was to study the effects of castration and heat stress on production performance, rumen fermentation and blood biochemical indexes of yellow cattle. Eighteen 16-month-old Junlian yellow bulls of similar weight ((292.35±28.71) kg) with different degree of castration (Full-castration group: FCG, hemi-castration group: HCG and sham-operation group: SOG) were selected and divided into three groups, with 6 replicates in each group and 1 bull in each replicate. Then divided into heat stress (July and August) and non-heat stress (September) periods according to the changes of the thermal-humidity index (THI) during the experiment. Then the impact of castration and heat stress on indicators of yellow cattle was analyzed The results showed as follows: 1) Compared with the non-heat stress period, bulls in the heat stress period had significantly higher THI, respiratory rate and rectal temperature (P<0.05).2) During the whole test period, the castration and heat stress significantly increased serum heat-shock protein 70, high-density lipoprotein (HDL-C), low-density lipoprotein (LDL-C) and estradiol concentrations (P<0.05); while serum testosterone, thyroxine (T4), insulin, and free fatty acids concentrations were significantly decreased (P<0.05); Besides serum glucose, T4 and LDL-C, castration and heat stress had a significant interaction effects on other serum index (P<0.05). 3) The full-castration and heat stress significantly decreased dry matter intake and average daily gain (ADG), and there was a significant interaction effect (P<0.05). 4) During the heat stress period, the castration significantly decreased crude protein, acid detergent fiber and Ca apparent digestibility, and serum total antioxidant capacity (T-AOC) (P<0.05), but significantly increased T-AOC in the non-heat stress period (P<0.05). 5) The castration and heat stress both significantly increased rumen pH (P<0.05), significantly decreased ammonia nitrogen (NH3-N), acetic acid (AA), and total volatile fatty acid (TVFA) concentrations (P<0.05); and both had significant interaction effects on rumen pH, NH3-N, AA and TVFA concentrations (P<0.05). In conclusion, castration and heat stress in bulls can affect the secretion of sex hormones concentrations and nutrient apparent digestibility, thereby reducing production performance, which provide a scientific basis for feeding management of beef cattle during heat stress periods. |
Key words: Junlian cattle heat stress castration production performance apparent digestibility serum biochemical indexes |