Earlier we found that the puerperal period of ewes lambing in February was finished by day 34 post partum.The aim of this paper was to study the puerperal changes in ewes that lambed in September. Structural changes in the endometrium of the caruncular region were studied in 12 Slovak Merino ewes that lambed in September. The animals were killed on days 7, 17, 25 and 34 post partum. Samples were taken from the caruncular region of their uterine horns. The tissue samples were fixed, dehydrated and embedded in paraffin, and 7-10 mm sections were stained with hematoxylin-eosin. Microscopic analysis was performed using a projection microscope. Simultaneously the collected material was stained with toluidine-blue, and examined on the semi-thin sections. The epithelium above the caruncles was entirely destroyed on day 7. Damaged mitochondria and dilated cisterns of the endoplasmic reticulum were found in the electron micrographs. On day 17, the epithelium covered gradually a sizeable caruncle. The glandular epithelium was considerably degenerated. The caruncle was markedly reduced on day 25, and the endometrium was covered with epithelium. The endometrium was totally covered with epithelium, and cellular ultrastructure was no more damaged on day 34 post partum. The study of micromorphology of endometrial structure in caruncular area revealed that also in ewes that lambed in September, the puerperium is finished by day 34 post partum. Its course and timing did not differ from that seen in ewes lambing in February. The results extend the knowledge of the puerperal changes in different season of the year. Caruncular region, endometrium, ewe, histological structures, post partum, season of the year One of the factors that may unfavourably affect fertility is the course of the involutional and reparatory processes of the uterus in the postpartal period. At the onset of postpartal reproductive activity it is necessary to take into account the breed, the season of the year, nutrition, and the length of suckling (Kudláã 1985; DoleÏel 1989). The macroscopic changes occurring during involution of the sheep uterus were reported by Foote and Call (1969); Crowder et al. (1982); Botha (1976); Van Wyk et al. (1972); Krajniãáková (1990); Greyling and Van Niekerk (1991) in goat, and Massányi (1996) in rabbits. A comprehensive histological study of the sheep uterus post partum was carried out by Uren (1935); and Van Wyk et al. (1972) who found that the involution process of the uterus was completed by day 28 post partum. Botha (1976) reported that both the season and lactation influence epithelisation of the caruncles. The author observed sheep that lambed during the out-of-mating season (August) to have epithelisation in the caruncular region finished on day 34 post partum whereas those that lambed in the lambing season (March) on day 30 post partum.

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KóÀová M., E. Békeová, M. Levkut: The Effects of Chlorine Intake on Some Morphometric Parameters of the Thyroid Gland in Lambs. Acta Vet. Brno 1999, 68: 191-195.The aim of the study was to determine whether drinking water containing two concentrations of chlorine (0.3 mg . l -1 or 1.8 mg . l -1 ) affects morphometric indicators of follicular epithelial cells and the diameter of thyroid gland follicles in young lambs.The height of follicular epithelial cells, the diameter of thyroid gland follicles, the frequency of epithelial cell height categories, and the frequency of follicular diameter categories were studied in two groups of lambs after two treatments: one for four weeks and the other for three months. The first group had access to drinking water with 0.3 mg . l -1 chlorine (short-term intake and low Cl concentration) for four weeks. The second group had access to drinking water containing 1.8 mg . l -1 chlorine (long-term intake and high concentration) for three months.A significant increase (P < 0.01) in follicular epithelial cell height and a significant frequency distribution shift to the higher cellular height categories was observed after intake of chlorinated water (0.3 mg . l -1 ), (P < 0.01 for cell height categories 3.1-4 and 4.1-5 µm) for four weeks. There was also a significant shift (P < 0.01 for cell height categories 4.1-5 and 5.1-6 µm) in lambs receiving 1.8 mg . l -1 chlorine in their drinking water for three months as compared to controls.The diameter of thyroid gland follicles significantly decreased (P < 0.01), and the percent of small thyroid follicles significantly increased (for diameter categories 20.1-40 and 40.1-60 µm P < 0.01 and P < 0.05, respectively) in lambs receiving 1.8 mg . l -1 chlorine in drinking water for three months as compared to controls.Our morphometric findings suggest that chlorine interferes with the thyroid metabolism in lambs, however, with no macroscopically detectable changes of the thyroid.

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