پديد آورنده :
كريمي، محمدتقي
عنوان :
تاثير كاهش تنش حرارتي در طول اواخر دوره آبستني بر عملكرد گاوهاي شيري هلشتاين
مقطع تحصيلي :
كارشناسي ارشد
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده كشاورزي
صفحه شمار :
ده،66ص.: مصور،جدول،نمودار
يادداشت :
ص.ع.به فارسي و انگليسي
استاد راهنما :
غلامرضا قرباني
استاد مشاور :
محمد خوروش، حميدرضا رحماني
توصيفگر ها :
شاخص دمايي-رطوبتي
تاريخ نمايه سازي :
21/11/92
استاد داور :
رحمان جهانيان، صبيحه سليمانيان زاد
چكيده فارسي :
به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي
چكيده انگليسي :
Effects of Heat Stress Abatement During Late Gestation on Holstein Dairy Cows Performance Mohammad Taqi Karimi mtkarimi3849@yahoo com Date of Submission December 17 2013 Department of Animal Science Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor G R Ghorbani ghorbani@cc iut ac irAbstractThe objective of this present study was to evaluate the effects of heat stress during the last 3wk of gestation on performance of multiparous Holstein cows n 20 Dry cows randomlyassigned to treatments approximately 21d before expected calving date based on matureequivalent milk production and parity Treatments were only imposed during the last 3 wk ofgestation and included heat stress HT n 10 or cooling CL n 10 The stall areas for CLcows equipped with sprinklers and fans that turned on at 0700 to 1900 h After parturient allcows were housed in a barn with cooling devices Air temperature and relative humidity ofeach pen were recorded every 15 min and temperature humidity index THI was calculated The average temperature humidity index during the last 3 wk of gestation was similar and notdifferent between treatments 69 66 and 69 82 respectively for CL and HT Heat stressedcows had higher rectal temperature P 0 0001 greater respiration rates P 0 0001 whencompared with CL cows Gestation length P 0 29 and dry period length P 0 3 was notdifferent between treatments Heat stress during the last 3 wk of gestation decreased DMI ofthe cows P 0 05 compared with cooling but not with postpartum P 0 03 In addition atendency of treatments by time interaction was observed P 0 07 Relative to HT cows CLcows had greater milk production P 0 05 No treatments effects on milk fat protein andSNF concentration P 0 62 P 0 054 P 0 053 Calf BW was 2 7 kg lighter for calvesborn from HT cows P 0 05 Colostrum density of HT and CL cows was 1 05 and 1 06g cm3 respectively P 0 01 The number of insemination for each conception for CL andHT cows was 1 9 and 2 2 respectively P 0 09 CL cows tended to have higher eating andchewing time P 0 13 and P 0 06 and their ruminating time were higher than HT cows P 0 03 In contrast standing time of CL cows were lower than HT cows P 0 01 Ingeneral results of this study indicate that heat stress abatement during late gestation behindof cows welfare improves dairy cows performance n the subsequent lactation Key words dairy cows heat stress gestation period temperature humidity index
استاد راهنما :
غلامرضا قرباني
استاد مشاور :
محمد خوروش، حميدرضا رحماني
استاد داور :
رحمان جهانيان، صبيحه سليمانيان زاد
