The structure, distribution and dimensions of skin strata and sweat glands have been investigated in Egyptian buffaloes and cattle. Samples from sixteen body regions were taken from three adult bulls of both species. Identical studies were also made on one buffalo calf and two buffalo embryos. Serial vertical and horizontal sections were cut from each body region using the ‘terpineol paraffin wax’ method. The following results were obtained.1. Buffalo skin is characterized by dermal papillae enclosing papillomatous epidermis. The fibrous structure of the dermis is similar in both species. In buffaloes, the average thickness of skin, main epidermis, papillomatous epidermis, and cornium is 6·5 mm., 50, 115, and 11μ respectively. The epidermis coefficient is 12 for the main epidermis and 18 for the papillomatous epidermis. In cattle, the average thickness of skin, epidermis and cornium layer is 4·3 mm., 51 and 5 μ respectively, while the epidermis coefficient is 8.2. The average number of hair follicles per sq.cm. of skin is 394 in the buffalo and 2633 in cattle. Each hair follicle is accompanied by two large lobulated sebaceous glands in the buffalo, and one small bilobed gland in cattle.3. There is no species difference in the histology of the sweat glands. Each hair follicle is accompanied by one sweat gland in both species. In the buffalo, the body of the sweat gland is oval and convoluted, while the duct is twisted at its attachment to the body. In cattle, the body of the gland is elongated while the duct is straight. The number of sweat glands per sq.cm. of skin is 394 in the buffalo and 2633 in cattle. The dimensions of the sweat glands are larger in buffaloes than in cattle. The length, circumference and sweating surface of the gland is 0·58, 0·47, and 0·276 sq.mm. in the buffalo, and 0·47, 0·26, and 0·124 sq.mm. in cattle respectively. The glandular surface of sweat glands per sq.cm. of skin is 1·07 sq.cm. in the buffalo and 3·08 sq.cm. in cattle.4. The type of sweat gland secretion is apocrine in both species. In the buffalo, successive stages of apocrine secretion are observed, and the merocrinelike form is rare. In cattle, the merocrine-like form prevails and the other stages are very rare. The theory (Findlay & Yang, 1950) of intraluminal transformation, of secretory products from coarse granularity to fluid homogeneity is supported. The effect of locality on the type of sweating activity is stressed.5. There are species differences in the distribution of blood vessels and capillaries. In the subepidermal level, the arterial branches are more frequent and superficial in buffaloes than in cattle. Capillaries are found in the dermal papillae of buffalo skin. The capillary loops encircling the hair follicle are more frequent in cattle than in buffaloes. The blood capillaries supplying the sebaceous glands are more numerous in the buffalo than in cattle. The blood supply of sweat glands is poor in both species.6. There are age differences in the skin histology. The number of hair follicles per sq.cm. of skin in a 5-months-old embryo, calf at birth, and adult buffaloes is 10560, 1248 and 400 respectively. There are no skin glands in the 1-month and 5-months-old embryos. The sweat gland in the calf is small in size and similar in structure to that of the adult. Calves have fewer sweat glands than adults.7. The body conformation and the degree of pigmentation are affected by species, breed and locality.8. The secreting activity of the sweat glands may be affected by the locality.9. It seems that there are species differences in the mechanism of heat convection and radiation, insensible perspiration and sensible perspiration, due to histological differences.

With One Text-figure)The sexual performance of the male is assessed by measuring semen characteristics, by studying the histology of the testis, and by measuring sexual libido (sex drive). There is always a physiological interaction between the testis, accessory sexual organs and anterior pituitary gland. Moreover, the output of the anterior pituitary is controlled by complex factors, mainly season, breed, age and nutrition. Seasonal variations in climatic conditions differ greatly with the locality (latitude). In the subtropics there is more seasonal fluctuation in atmospheric temperature and less variation in daylength than in the temperate zones.The common practice for sheep breeding in Egypt is to arrange the mating season in the summer so that lambing coincides with the winter months when climatic conditions are favourable for vegetation. Some farmers, however, do not follow this practice but permit continuous association of the two sexes, and consequently lambs are dropped throughout the year. Other breeders arrange two mating seasons a year; spring and autumn. Knowledge concerning the breeding season of fat-tailed sheep should provide the necessary background for the successful application of artificial insemination, which may be of special value in fat-tailed sheep where the fat tail handicaps free coitus.This work was an attempt to evaluate semen characteristics in Egyptian fat-tailed sheep under natural conditions. It was also hoped to find out the seasonal variation in semen quality for both Ossimi and Rahmani breeds which are widely distributed in the Delta. MATERIALS AND METHODS (1) Experimental animals and managementTwelve fat-tailed rams of two breeds (nine Ossimi and three Rahmani) were available. The rams of each breed were derived from flocks inbred for over 12 years and kept at the Animal Breeding Research Farm, Giza, Egypt (30° N.). They were from 1-5 to 2-5 years old at the beginning of the experiment which started on 1 March 1951 and lasted for 12 months. The rams were housed in semi-open sheds all in one group. They were allowed to graze 6 hr. a day (from 8 a.m. to 2 p.m.) in the neighbouring fields. During the summer months, they were allowed to graze early in the morning and late in the afternoon so as to avoid the hot weather during midday. On the day of semen collection they were not sent for grazing and were kept near the laboratory.The experimental animals were fed ad lib. on green clover (Trifolium alexandrinum) starting from January until May. During summer months the diet was supplemented with hay ad lib. and 1 lb. of a mixture made of bran, barley, rice polish, horse beans and cottonseed cake in equal parts. A shaded water supply was available all the day long. The animals were shorn twice yearly during May and September.The different seasons were defined as follows(2) Semen tests Semen was collected from all the rams by an artificial vagina (A.V.) every 10 days throughout the experimental period (12 months). The temperature of the A.V. at collection ranged from 40 to 45° C. Colle...

Forty adult (15 months old) fat-tailed Egyptian rams and ewes of the Rahmani and Ossimi breeds were available at the Animal Breeding Research Farm, Giza, Egypt (30° N.). Body temperature and respiration rates were measured twice weekly throughout the year 1953–4. On days of observations, four readings were taken at 10 a.m., 12 noon, 2 p.m. and 4 p.m. Skin temperature was measured once weekly at noon for nine body regions, using a precision bridge thermometer. The effects of docking and pregnancy were also studied.1. There were seasonal variations in body temperature and respiration rate. The maximum values were during summer and the minimum during winter. The seasonal rate of change was greater in respiration rate than in body temperature.2. Body temperature was 39·1 and 39·0° C. for the Ossimi rams and ewes respectively, while it was 38·9° C. for both Rahmani sexes. Respiration rate per minute was 42·0, 39·3, for Ossimi rams and ewes and 38·2 and 35·9 for Rahmani rams and ewes respectively. Body temperature and respiration rate were higher in the Ossimi than in the Rahmani breed, and in the males than in the females. Breed differences may be related to anatomical differences such as body conformation, size of skull and tail, thickness of skin and subcutaneous fat and differences in coat characteristics. Sex differences may be associated with the live weight of the animals as well as differences in the hormonal system.3. Pregnancy had no effect on body temperature and respiration rate in either breed.4. Different experimental groups reacted similarly with respect to diurnal variations in body temperature and respiration rate; the lowest values being at 10 a.m. and the highest at 4 p.m. Maximum body temperature and respiration rate preceded maximum environmental temperature by 2–4 hr. The diurnal rate of change in respiration rate was higher than that in body temperature. The diurnal changes in body temperature and respiration rate of animals were mainly due to the changes in the environmental temperature throughout the day.5. (a) Skin temperature varied from 33·7 to 39·7° C., according to season and body region. Seasonal variations in skin temperature of different body regions showed the same trend.(b) Highest skin temperatures were recorded for middle and upper fat tail, back thoracic and middle scrotum regions, while the lowest were recorded in lower and upper scrotum, lower tail and neck ventral regions. The breast region had an intermediate skin temperature. The different skin temperatures were due to anatomical differences such as the thickness of subcutaneous fat, density of covering wool or to differences in the amount of blood supply.6. Docked rams had a lower skin temperature and respiration rate than controls, denoting better heat regulation. This may be due to metabolic differences or anatomical changes in the body such as the thickness of subcutaneous fat.

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A total of fifty buffaloes, thirty-five Shorthorn and Shorthorn grades and twenty-nine Egyptian (Baladi) cows of different ages were used to study the thermal reaction mechanism by exposing the animals to direct solar radiation followed by shade. The thickness of the skin was also measured in all animals as it is one of the main factors in heat regulation. The results were as follows:1. There were species and breed differences in the thermal reactions. Buffaloes were more hyperthermic when exposed to direct solar radiation than either Shorthorn or Egyptian cattle. The Shorthorns were more affected by ambient heat than Egyptian cattle.2. The skin thickness of the buffalo was double that of the cattle. In all animals the thickness of the skin increased with age.3. It is suggested that the adaptability of farm animals to tropical and subtropical zones is better assessed under shade and under normal husbandry conditions than by exposing them to direct sunlight.