摘要
为比较热应激与喷淋-风扇系统对热应激期不同泌乳期奶牛生理、生产性能、发病率的影响,将泌乳牛按泌乳时间分为新产牛(0~21 d)、泌乳前期(22~120 d)、泌乳中期(121~200 d)、泌乳后期(201~305 d)奶牛,分别随机选择体况、年龄、泌乳时间相近的健康经产(2~4胎)各泌乳阶段奶牛10头,共计40头作为试验对象。按养殖场日常饲养和管理方式,不做人工干预,热应激期采用喷淋-风扇系统降温。每日测定牛舍温度、相对湿度、风速、直肠温度、呼吸频率、日产奶量、日大缸奶乳成分、日新发肢蹄病、酮病、临床型乳房炎和隐性型乳房炎等。结果表明:喷淋-风扇系统下,热应激期牛舍内温度接近30℃,相对湿度为82%,风速达1.35 m·s^(-1),湿热指数处于中度热应激。热应激期,各泌乳期奶牛直肠温度平均分别升高0.9、0.7、0.6、0.5℃,呼吸频率平均分别上升32.9、29.1、29.3、28.5次·min^(-1),较非热应激期均极显著(P<0.01)升高;新产牛、泌乳前期和中期奶牛日单产均极显著(P<0.01)下降,降幅分别为9.17%、18.97%和13.23%,而泌乳后期奶牛无显著变化(P>0.05),新产牛泌乳启动时奶产量下降,各阶段泌乳牛泌乳峰值均降低;全群泌乳牛乳脂率、脂蛋比均极显著(P<0.01)下降,乳蛋白显著(P<0.05)降低,乳脂率、脂蛋比、乳蛋白含量分别降低0.29百分点、5.23%和1.61%;全群泌乳牛肢蹄病、酮病、临床型乳房炎和隐性型乳房炎发病率分别升高5.77、0.78、2.60和5.77百分点。结果说明:喷淋-风扇系统对舍内热环境改善不显著;热应激影响新产牛和泌乳前期、中期奶牛直肠温度和呼吸频率,使新产牛泌乳启动时产奶量下降,各阶段泌乳牛产奶峰值降低;全群泌乳牛乳品质降低,发病率升高。
To investigate the influence of heat stress period and spray-fan cooling system on physiology,milk production and morbidity of dairy cows(in different lactation stages),lactating cows were divided as late perinatal(0-21 d),the early lactation(22-120 d),the mid lactation(121-200 d),and the late lactation(201-305 d)according to days in milk.Ten healthy cows(with similar body condition,ages,lactation and 2-4 parities)were selected in each lactation stage(the total was 40)in this study.All cows were managed as usual without manual intervention,spray-fan cooling system was used during the heat stress period.Temperature,relative humidity,wind speed of the cowshed,rectal temperature,respiratory rates,milk production,milk composition,new cases of hoof disease,ketosis,clinical mastitis and subclinical mastitis were recorded or measured every day during experiment.The results were as follows:Average temperature in cowshed during the heat stress period was nearly 30℃ under spray-fan cooling system,relative humidity was 82%,wind speed was 1.35 m·s^(-1) and temperature humidity index(THI)was within the range of moderate heat stress;The average rectal temperature of cows in each lactation stage increased by 0.9℃,0.7℃,0.6℃ and 0.5℃,respectively,and respiratory rate increased by an average of 32.9,29.1,29.3 and 28.5 times per minute,respectively,which was significantly higher than those in non-heat stress period(P<0.01);Average daily milk yields in late-perinatal,early-lactation and mid-lactation decreased significantly(P<0.01)during heat stress period(with a decrease of 9.17%,18.97% and 13.23%,respectively),whereas there was no significant change in late lactation stage(P>0.05);Initial milk yield of late-perinatal cows decreased,peak value of milk production decreased in all stages.Milk-fat percentage and milk fat/protein of all cows decreased significantly(P<0.01),milk protein also decreased significantly(P<0.05),the decreases were 0.29 percent,5.23% and 1.61%,respectively;Incidence of hoof disease,ketosis,clinical mastitis and subclinical mastitis of all cows increased by 5.77,0.78,2.60 and 5.77 percent,respectively.In conclusion,spray-fan cooling system could not significantly improve the thermal environment of cowshed.Heat stress greatly impacted the rectal temperature and respiratory rate of late-perinatal cows,early-lactation cows and mid-lactation cow,leading to the decrease of initial milk production,peak milk yield of cows in all lactation stages and milk quality,and the increase of morbidity.
作者
沈留红
程李杰
尤留超
雍康
罗正中
陈久兵
骆巧
余树民
曹随忠
SHEN Liuhong;CHENG Lijie;YOU Liuchao;YONG Kang;LUO Zhengzhong;CHEN Jiubing;LUO Qiao;YU Shumin;CAO Suizhong(The Key Laboratory of Animal Disease and Human Health of Sichuan Province/The Medical Research Center for Cow Disease,College of Veterinary Medicine,Sichuan Agricultural University,Chengdu 611130,China;College of Animal Science and Technology,Chongqing Three Gorges Vocational College,Chongqing 404155,China)
出处
《浙江农业学报》
CSCD
北大核心
2021年第9期1602-1610,共9页
Acta Agriculturae Zhejiangensis
基金
四川省科技厅科技计划(2019YJ0650)
国家重点研发计划(2018YFD0500900)
四川农业大学本科科研兴趣培养计划(KY2021140)。
关键词
喷淋-风扇系统
奶牛
热应激
生理参数
产奶性能
spray-fan cooling system
dairy cows
heat stress
physiological indexes
milk production
