摘要
【目的】探讨南方夏季高温高湿气候条件下,横向交互送风系统对肉牛舍温热环境、肉牛生理生化指标及生产性能的影响,以期评价此肉牛防暑环境调控系统的技术经济效果。【方法】试验采用单因子完全随机设计,选择健康、体重相近((290.05±7.60)kg)的8月龄西门塔尔公牛30头,随机区组饲养于2栋相邻且构造相同的钟楼式棚舍中,试验组所在牛舍加装横向交互送风系统,对照组所在牛舍采用自然通风。试验期为2019年6月30日至7月16日,共17 d,其中预试期为前3 d,正式期为后14 d。正式试验期内前7 d,于每日的5:00、10:00、14:00、18:00、22:00测定舍内风速、干球温度和湿球温度,计算温湿指数和体感温度,并同时测定肉牛的直肠温度和呼吸频率。在全部正式试验期间,每天记录每圈栏的投料量,并于次日上午6点对剩料进行清理和称重,计算采食量。于正式试验期内第1和14天的上午7:00-8:00,对所有试验牛进行空腹称重,记录始末体重,用于计算平均日增重和料重比等生产性能指标并进行经济效益评估;同时采集血液及粪便样本,用于测定血清中的无机离子、生化指标、激素水平及粪便中的皮质醇水平。【结果】(1)试验组的横向交互式送风系统处理可显著提高舍内风速(P<0.01),从而极显著的降低试验组肉牛的体感温度、肉牛在10:00、14:00、18:00、22:00的直肠温度以及肉牛在10:00、14:00、18:00的呼吸频率(P<0.01);与对照组肉牛相比,试验组肉牛直肠温度和呼吸频率随环境温度升高的增幅分别减少45%和42%;试验组与对照组的舍内干球温度、相对湿度及温湿指数差异不显著(P>0.05)。(2)试验结束时,试验组肉牛血清中钙离子含量显著低于对照组(P<0.05),钾离子、钠离子、镁离子及氯离子含量均差异不显著(P>0.05);血清生化指标结果显示,试验组肉牛血清中的热应激蛋白70、总蛋白、甘油三酯、葡萄糖含量均显著高于对照组(P<0.05),血清白蛋白、球蛋白及总胆固醇含量差异不显著(P>0.05);激素水平测定结果显示,试验组肉牛的粪便及血清中皮质醇水平均显著低于对照组(P<0.05),三碘甲状腺原氨酸和甲状腺素在试验组和对照组间差异均不显著(P>0.05)。(3)生产性能测定显示,试验组与对照组肉牛的初始体重及结束体重均差异不显著(P>0.05),但试验组肉牛的平均日增重(P<0.01)及平均干物质采食量(P<0.05)显著高于对照组,料重比显著低于对照组(P<0.05),利润可提高10.68%。【结论】横向交互送风可以显著增加舍内空气流速,降低体感温度,改善西门塔尔牛代谢,提高生产性能,增加高温高湿环境下肉牛生产的经济效益。
【Objective】This study was conducted to explore the effects of cross-ventilation system on cowshed thermal environment,physiological and biochemical indexes,and production performance of beef cattle under the high temperature and humidity climate in summer of southern China,to evaluate the technical and economic effects of the environment control system for beef cattle heatstroke prevention.【Method】One-factor completely randomized design was introduced in this study.Thirty healthy 8-month-old Simmental bulls with similar body weight((290.05±7.60)kg)were randomly assigned into two adjacent sheds with the same structure.The experimental group was equipped with the cross-ventilation system,and natural ventilation was used in the control group.The experimental period was from June 30 to July 16,2019,a total of 17 days,in which the pre-test period was the first 3 days,and the formal period was the last 14 days.The wind speed,dry-bulb temperature and wet-bulb temperature were measured at 5:00,10:00,14:00,18:00 and 22:00 every day in the first 7 days of the formal test period.The temperature-humidity index and sensible temperature were calculated.Meanwhile,the rectal temperature and respiratory rate of beef cattle were measured.During the whole formal period,the feeding amount was recorded every day,and the remaining materials were cleaned and weighed at 6 a.m of the next day to calculate the feed intake.From 7:00 to 8:00 in the morning on the first day and the fourteenth day of the formal test period,all cattle were weighed before feeding to calculate the average daily gain,feed weight ratio and other production performance indicators,and the economic benefit was evaluated.Simultaneously,the blood and fecal samples were collected for determination of inorganic ions,biochemical indexes and hormone levels in serum and cortisol levels in feces.【Result】The results showed that:(1)in the experimental group,the cross-ventilation system could significantly increase the wind speed in the shed(P<0.01),thus significantly reduced the sensible temperature,the rectal temperature at 10:00,14:00,18:00,22:00,and the respiratory rate of beef cattle at 10:00,14:00,18:00(P<0.01).Compared with the control group,with the increase of ambient temperature,the increase of rectal temperature and respiratory rate in the experimental group decreased by 45%and 42%,respectively.There was no significant difference in dry-bulb temperature,relative humidity and temperature-humidity index between the experimental group and the control group(P>0.05).(2)At the end of the experiment,the serum calcium content in the experimental group was significantly lower than that in the control group(P<0.05),while no difference was found concerning the contents of potassium ion,sodium ion,magnesium ion and chloride ion(P>0.05).The results of serum biochemical indexes showed that the contents of heat stress protein 70,total protein,triglyceride and glucose in bovine of the experimental group were significantly higher than those in the control group(P<0.05),and no significant difference was observed for the contents of serum albumin,globulin and total cholesterol(P>0.05).The results of hormone levels showed that the levels of cortisol in feces and serum of the cattle in experimental group were significantly lower than those in control group(P<0.05),and triiodothyronine and thyroxine had no significant difference in cattle between the experimental group and the control group(P>0.05).(3)The production performance test showed that there was no significant difference in initial body weight and end body weight between the experimental group and the control group(P>0.05),while the average daily gain(P<0.01)and average dry matter intake(P<0.05)of the experimental group were significantly higher than those of the control group,the feed-to-weight ratio of the experimental group was significantly lower than that of the control group(P<0.05),and the profit in the experimental group was increased by 10.68%.【Conclusion】The cross-ventilation system could significantly increase the air velocity of the shed,reduce the sensible temperature,improve the metabolism of Simmental cattle,promote the production performance,and increase the economic benefits for beef cattle production in high temperature and humidity environment.
作者
房昊源
杨亮
王洪壮
曹锦承
任万平
魏胜娟
颜培实
FANG HaoYuan;YANG Liang;WANG HongZhuang;CAO JinCheng;REN WanPing;WEI ShengJuan;YAN PeiShi(College of Animal Science and Technology,Nanjing Agricultural University,Nanjing 210095;College of Animal Science,Xinjiang Agricultural University,Urumqi 830052)
出处
《中国农业科学》
CAS
CSCD
北大核心
2022年第5期1025-1036,共12页
Scientia Agricultura Sinica
基金
江苏省农业科技自主创新资金(CX(21)3136)
中央高校基本科研业务费专项资金(KYYJ202102)
国家重点研发计划(2018YFD0501706)
国家自然科学基金(31501930)。
关键词
横向送风
肉牛
体温调节
生理生化指标
生产性能
经济效益
the cross-ventilation
beef cattle
thermoregulation
physiology and biochemistry indexes
production performance
economic benefit
