Review of the impact of heat stress on reproductive performance of sheep  

作　　者：William H.E.J.van Wettere Karen L.Kind Kathryn L.Gatford Alyce M.Swinbourne Stephan T.Leu Peter T.Hayman Jennifer M.Kelly Alice C.Weaver David O.Kleemann Simon K.Walker 

机构地区：[1]The University of Adelaide,School of Animal and Veterinary Sciences,Davies Livestock Research Centre,Roseworthy Campus,Mudla Wirra Rd,Roseworthy,South Australia 5371,Australia [2]The University of Adelaide,Robinson Research Institute,Adelaide Medical School,North Terrace,Adelaide,South Australia 5000,Australia [3]The University of Adelaide,School of Agriculture,Food and Wine,Waite Research Institute,Urrbrae,South Australia 5064,Australia [4]South Australian Research and Development Institute,Primary Industries and Regions SA,Government of South Australia,Climate Applications,Waite Research Precinct,Urrbrae,South Australia 5064,Australia [5]South Australian Research and Development Institute,Primary Industries and Regions SA,Reproductive Biology,Livestock Sciences,Turretfield Research Centre,129 Holland Rd,Rosedale,South Australia 5350,Australia

出　　处：《Journal of Animal Science and Biotechnology》2021年第3期859-876,共18页畜牧与生物技术杂志（英文版）

基　　金：This review was funded as part of a Meat&Livestock Australia Ltd.tender entitled The effects of heat stress and predicted climate change scenarios on reproductive performance of the Australia sheep flock(Project code:L.LSM.0024).

摘　　要：Heat stress significantly impairs reproduction of sheep,and under current climatic conditions is a significant risk to the efficiency of the meat and wool production,with the impact increasing as global temperatures rise.Evidence from field studies and studies conducted using environmental chambers demonstrate the effects of hot temperatures(≥32℃)on components of ewe fertility(oestrus,fertilisation,embryo survival and lambing)are most destructive when experienced from 5 d before until 5 d after oestrus.Temperature controlled studies also demonstrate that ram fertility,as measured by rates of fertilisation and embryo survival,is reduced when mating occurs during the period 14 to 50 d post-heating.However,the contribution of the ram to heat induced reductions in flock fertility is difficult to determine accurately.Based primarily on temperature controlled studies,it is clear that sustained exposure to high temperatures(≥32℃)during pregnancy reduces lamb birthweight and will,therefore,decrease lamb survival under field conditions.It is concluded that both ewe and ram reproduction is affected by relatively modest levels of heat stress(≥32℃)and this is a concern given that a significant proportion of the global sheep population experiences heat stress of this magnitude around mating and during pregnancy.Despite this,strategies to limit the impacts of the climate on the homeothermy,behaviour,resource use and reproduction of extensively grazed sheep are limited,and there is an urgency to improve knowledge and to develop husbandry practices to limit these impacts.

关 键 词：FERTILITY Heat stress OOGENESIS PREGNANCY SHEEP SPERMATOGENESIS 

分 类 号：S826[农业科学—畜牧学]