Adaptive Capacity of Saidi Sheep and Goats to Heat Stress and Diurnal Variation under the Hot Dry Conditions of Upper Egypt

Document Type : Original Article

Authors

1 Nadi Elseid St.

2 Animal Production Research Institute

Abstract

The present work investigate the adaptive capacity of the indigenous Saidi sheep and Saidi goats (109 and 80 animals, respectively), to the prevailing hot dry condition of Upper Egypt. Heat stressors were; summer heat stress (SHS) ;exercise heat stress (EHS), animals walk for 7 km under solar radiation ; the third stressor was winter cold stress (WCS) outdoor .
Exposing the animals to SHS (THI=103.2), raised significantly respiration rate (RR) of Saidi sheep and goats by 206 and230 %, respectively; with incidence of deep breath. Rectal temperature (RT) and skin temperature (ST) increased significantly (P≤ 0.05) with SHS. Carry on effect , continue up to 8 pm.
Exposing animals to exercise heat stress (EHS) increased RT and ST by 1.9 oC and 4.7oC, for the two species, respectively. Respiration rate, multiplied by more than 5 folds for both Saidi sheep and goats. Changes in the GV, differ in between the two species ,it increased by 575% in sheep and only by175% in goats. Local Saidi sheep and goats response to physical heat stress by vast accelerating their RR; however, Saidi sheep need to go further to deep breath to cope the extra stressors
Winter cold stress at 4am (THI=51), reduced RT of Saidi sheep and goats by 0.7and 0.40C, respectively; from that at its comfortable zone at 2 pm (THI = 62). Skin temperature declined by 3.7 and 3.9oC, with WCS. Changes in respiratory parameters with cold stress were limited, compared to that of the thermal ones.

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