Means of alleviating summer heat stress on Friesian cows for promoting milk production
Abstract: This study was executed under a subtropica1 region with summer temperatures commonly over 30°C. Twenty postpartum lactating Friesian cows were used to determine the combined effect of the natural environmental conditions (NEC) on physiological and lactational performance during winter and summer seasons (4 months each). In addition to evaluate two different means of heat stress amelioration during summer. Cows were divided into 4 similar groups (5 of each). Four groups were conducted under (NEC), one in winter and three in summer seasons.
The 1st and the 2nd trials were executed under the NEC of winter (G1) and summer (G2) seasons without any artificial trials. Summer heat load was alleviated by two different trials, cooling system for the 3rd group (G3) and by feed additives of an enzymatic compound (ZADO product) for the 4th group (G4). All cows were kept under the same managerial practice.
Ambient temperature (AT), relative (RH) and temperature humidity index (THI) averaged 16.6 °c, 63.1 % and 61.1 during winter (cool period) and 32.5 °c, 60.2% and 83.4 during summer (hot period). THI was strongly and positively correlated with body temperature (0.6) and respiration rate (0.6) (0.6) and negatively with milk yield (0.60). Summer heat stress declined daily milk yield (DMY) by about 4.8 kg/day (28.5%) in G2 compared with G1. Milk performance of these Friesian cows as expressed by DMY (kg/day) and milk constituents (g/day) were reduced due to summer heat stress by about 28 to 38 %. When heat stress of summer was alleviated, milk production performance was improved and increased greatly by using cooling mean (20 to 30%) and by using feed additives mean (25 to 39%). It is clear that the later mean was better than the former mean by about 3-7%. However, both means failed to maximize the milk performance of stressed cow (G3 and G4) as obtained by cows under comforted conditions (G 1). There were insignificant differences between G1 and G4 cows in milk production performance. Environmental conditions should target the effect of high AT and should be modified at the critical times during the day in summer season when the cows are stressed.
Keywords: Heat Stress, Friesian Cows, Milk Production
Publication year 2008
Pages 117-130
Availability location معهد بحوث الانتاج الحيوانى- شارع نادى الصيد- الدقى - الجيزة
Availability number
Organization Name
City طابا
serial title Sixth Scientific Conference. Taba.
Author(s) from ARC
External authors (outside ARC)
    جمال عاشور حسن جامعة القاهرة
    منصور محمد احمد الجمهورية العربية السورية
    ربيع رجب صادق جامعة القاهرة
Agris Categories Animal physiology - Nutrition
AGROVOC
TERMS		 Cows. Heat stress. Milk production.
Publication Type Conference/Workshop
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