We hypothesized that the hoof trimming in sheep in dorsal recumbency implicates a short but intensive stress situation and that the sedation with xylazine causes a decrease in the stress response in this situation. Ten healthy female merino meat sheep were randomly divided into two groups receiving either xylazine hydrochloride (0.1 mg/kg body mass (BM) applied intramuscularly) or a placebo treatment with 0.9% NaCl. Routine hoof trimming was performed in a tilt table and vital signs (rectal temperature (RT), heart rate (HR), and respiratory rate (RR)), 33 different behavioral traits and blood cortisol concentrations were recorded throughout the experiment at six different time points (total of 55 min). The procedure itself elicited a clear stress response (increase in the RR, RT, defensive movements, lip twitching, swallowing, and flight behavior). Parallelly, the blood cortisol concentrations were increased, reaching their maximum with 81.5 ng/ml in the control group when the sheep were tilted back into a standing position. In the sedated sheep, no increase in the RR and RT and a decrease in the HR were observed. In addition, the behavioral signs showed a decrease in flight, defensive, and general stress behavior (decrease in licking, movement of head and legs, and sitting on knees), complemented by the serum cortisol concentrations showing 2.28 times reduced concentration at the end of the procedure, compared to the control sheep. The results confirm our hypothesis and support the conduction of future trials investigating the feasibility and benefit of a sedation of sheep prior to routine hoof trimming under practical circumstances.

The histological and functional changes of 31 corpora lutea of Egyptian buffaloes during the various phases of the oestrous cycle were studied. The volumes of the corpora lutea were calculated, the volume per cell, the cell volume and the volume of the intercellular spaces were estimated from transverse serial sections stained with haematoxylin and eosin, Mallory's triple stain or van Gieson's stain. The nuclear volumes were also determined and the cytoplasmic volume was calculated. The progesterone content was estimated using column absorption chromatography and a counter-current distribution system. It was concluded that the luteal cells increase both in volume and in number due to mitosis. The luteal cells decrease in volume after the 15th day after ovulation, the cells lose their distinct outlines in the regressive stage and disappear completely in the corpus albicans. There was a parallel increase in luteal cell volume and progesterone content until the 15th post \ x=r eq-\ ovulatory day followed by a decrease in the regressive phase and disappearance of the hormone in the corpus albicans. A highly significant correlation (r = +0\m=.\875) was found between the progesterone content and the cytoplasmic volume. Progesterone concentration/g. luteal tissue increased from the corpus haemorrhagicum to the mature corpus luteum, decreased in the regressive corpus luteum and completely disappeared in the corpus albicans.

SUMMARYSkin biopsy samples from imported Merino and ⅝ Merino/⅜ Barki were examined from birth to the age of 1 year. Birthcoat fibre type arrays and fibre-follicle relationships were also studied.Merino lambs had a greater S/P ratio than ⅝ Merino at all ages; values at 1 year of age were 9·98 and 6·87 respectively.The ⅝ Merino lambs showed a wider range of follicle diameters than Merinos from birth to 1 year of age.The ratio of primary to secondary follicle diameters showed higher values in ⅝ Merino than in Merinos. Merino gave lower values of follicle wall thickness than ⅝ Merino.In Merino birthcoat samples, only one array was plain, representing 4%, whereas the rest were saddle. In ⅝ Merino the majority of fibre type arrays were plain, representing 75 %, whereas the rest were saddle and plateau.In Merino, because of the absence of halo hairs and super sickles, only two samples had few super sickle B; primary central follicles were occupied by sickle fibres, medium with large sickle ends as well as curly tips, and primary lateral follicles had mostly medium and fine curly tips, only four samples had sickle fibres, and secondary follicles produced medium and fine curly tips and histerotrichs.In ⅝ Merino primary central follicles produced halo hairs, super sickle A, A', B and occasionally sickle fibres, primary lateral follicles grew super sickle A, A', B, sickle fibres and curly tip fibres, and secondary follicles had medium and fine curly tips and histerotrichs.

In a study of two breed groups, coarse wool Barki and f Merino f Barki, data were obtained on skin histology from birth to the age of 1 year, birthcoat fibre type arrays and fibre-follicle relationship.The | Merino exceeded Barki lambs in the maximum S/P ratio, values of which were 3-40 and 5-64 obtained at 6 and 8 months in Barki and § Merino respectively.Internal diameters of primary follicles ranged from 39-0 to 64-7 and from 41-0 to 56-8 fim; those of secondaries ranged from J9-8 to 34-9 and from 22-6 to 33-3 fim in Barki and f Merino respectively.The ratio of primary to secondary follicle diameters showed high values in both breed groups; averages were 1-89 and 1-71 for internal diameter and 1-86 and 1-71 for external diameter in Barki and f Merino respectively.Birthcoat fibre type arrays were mostly saddle, only 8-3 % were plateau (P 3 ) in both breed groups.