![]() | Only 14 pages are availabe for public view |
Abstract The present study was carried out in Maryout Research Station (32º N Latitude), situated 35 kilometers southwest of Alexandria and belongs to the Desert Research Center (DRC), Ministry of Agriculture and Land Reclamation. The first season of the experiment was conducted throughout the Maintenance Energy Project. This project was supported by the US-Egypt Joint Science and Technology Fund Program Number 404 (2009-2012), under the title ”Effects of Nutritional Plane on the Maintenance Energy Requirement of Goats”, while the second season was done after the project was finished. The study was planned to explain the effect of the environmental stresses (i.e. feed and climatic changes) on the histological and histochemical structures of the Baladi and Shami goats’ skin. The relation between the results of the investigation and the quality and rate of hair production was studied to account for changes in coat structure. It can also drew attention to the impacts of these environmental stresses on the adaption and performance of both Baladi and Shami goats under Egyptian desert conditions.The experiment was concerned with the effects of a limiting nutritional plane in two seasons (summer and winter) on the performance of female goats of the two breeds (i.e. Baladi and Shami). Twenty four adult female goats (twelve Baladi and twelve Shami goats) between 3 and 5 years of age with an average body weight of 32.91 kg ± 3.79 and 32.57 kg ± 6.33, respectively, were used. Animals in each breed were randomly divided into two groups (6 animals for each) according to the feeding levels, 50% or 100% of the maintenance energy requirements. The animals were kept in pens roofed with stainless steel sheets and a semi-open yard surrounded by a wire fence. They were put in two nutritional planes of mixed forage-concentrate diet in which feed intake level was given at 100 or 50% of the maintenance energy requirements, based on body weight and body condition score 3, calculated according to NRC (2007). Ambient temperature, AT and relative humidity, RH were recorded simultaneously twice a week in both seasons. Rectal temperature (RT), skin temperature (ST), coat temperature (CT) and respiration rate (RR) were recorded simultaneously twice a week at 08:00 am and 14:00 pm in both seasons. Hair coat characteristics (Fibre Diameter; FD, Fibre length; FL, S/P ratio and follicles dimensions: external and internal diameter and wall thickness) and histochemical parameters were considered. In addition, blood hormones (thyroid gland, T3 and T4, cortisol, aldosterone and ADH (General arginine vasopressin) were measured. |