Abattoir survey of acquired reproductive abnormalities in ewes

Abnormalities of the reproductive tract of female sheep were studied by exa mining 9970 reproductive tracts from cull ewes and 23,536 tracts from nulli parous sheep (prime lambs) over a period of 12 months in abattoirs in south -west England. Overall, 3.37 per cent of the tracts were pregnant (8.11 per cent of cull ewes, and 1.36 er cent of nulliparous sheep), with a peak inc idence between September and December. A total of 655 ewes (6.57 per cent) and 459 nulliparous sheep (1.95 per cent) had acquired abnormalities of the reproductive tract. Within these totals, abnormalities of the ovaries acco unted for 3.51 per cent (for the ewes) and 10.68 per cent (for the nullipar ous sheep) of all the abnormalities, and abnormalities of the ovarian bursa and uterine tube accounted for 42.1 per cent (for the ewes) and 5.23 per c ent (for the nulliparous sheep). In addition, uterine lesions (hydrometra a nd metritis) accounted for 9.92 per cent (for the ewes) and 13.51 per cent (for the nulliparous sheep); lesions of the cervix and vagina (total of 1.4 4 per cent) and Cysticercus tenuicollis cysts associated with the reproduct ive tract (total of 3.05 per cent) were less common. Among the ewes the mos t common ovarian lesions were ovulation tags, and follicular cysts were the most common in nulliparous animals. Lesions such as bursitis, parametritis and abscesses of the reproductive tract were much more common in cull ewes than in nulliparous sheep, probably having arisen from peripartum infectio ns. Hydrosalpinx and hydrometra, in which the intraluminal fluid was clear, were present at relatively high incidence in nulliparous animals, but not in cull ewes. The proportion of tracts containing macerated fetal remnants (2.14 per cent of all abnormalities in cull ewes) was lower than expected. It was considered that the functional significance of many of the lesions, such as ovulation tags and C tenuicollis cysts, was likely to be low, altho ugh in some cases of the latter calcification of the cyst had occluded the uterine tubes. Other lesions, notably hydrosalpinx, bursitis and metritis w ere likely to have made the affected animals sterile. The acquired abnormal ities were therefore more significant in terms of individual animal inferti lity than as a major cause of infertility in flocks.