HEAT STRESSHZ2热应激.ppt

热应激对奶牛的影响Effects Of Heat Stress On Dairy CattleDr. Mark KujawaDiamond V Mills 报告的内容Topics to Present 热应激是什么？ What is heat stress? 热产自哪里？ Where is heat produced? 奶牛如何应对热应激？ How does the cow manage it? 什么是热应激？What Is Heat Stress? 舒适区Comfort Zones 温度和湿度均可以引起热应激Heat Stress Is Caused By Both Temperature And Humidity 温度和湿度很高时生产性能下降Production Decreases When Temperature and Humidity Are High 产热Heat Production 代谢产热The Metabolic Furnace 如果产热大于热量的散失……… If Heat Gain Is Larger Than Heat Loss……… 内部体温增加…….. Internal Body Temperature Increases…….. ……..能量需要增加 …….. Energy Requirements Increase 热量的散失Heat Dissipation 干物质采食量下降Dry Matter Intake Decreases 对瘤胃的影响Rumen Effects 对瘤胃的影响Rumen Effects 对瘤胃的影响Rumen Effects 对瘤胃的影响Rumen Effects …………产奶量和乳脂下降…………Milk Production And Milk Fat Declines 维持能量需要增加 Maintenance energy requirements increase 干物质采食量下降 Dry matter intake decreases 产奶量会下降多少？How Much Does Milk Production Decrease? 产奶量下降12-50% 12-50% Decrease In Milk Production 采食量会下降多少？How Much Does Feed Intake Decline? 采食量和会下降约40%或更多！ Feed Intake Can Reduce by 40% or More! 犊牛出生重受热应激影响 Calf Birth Weight Is Affected By Heat Stress 出生重约下降15% Birth weight can drop by 15% 热应激对瘤胃有显著影响 Hest Stress Has A Significant Affect On The Rumen 热应激引起能量需要量的变化 Heat Stress Causes Changes in Energy Requirements 热应激时瘤胃功能发生变化 Rumen Function Changes In Heat Stress 谢谢！Thank You! Without understanding heat stress and developing effective strategies to maintain comfort, cows quickly loose production as they move towards a heat stress condition. When cows become stressed, milk production declines due to an increase in the maintenance energy required to eliminate excess heat while dry matter intake declines. Without taking relative humidity into consideration in this example, as temperature increases from 50o to 104°, the energy requirement increases by 32% units over the requirements at the thermal neutral zone. About 50 perce