Abstract

To determine the prevalence of mastitis in hill-country ewes, 1824 mixed-age Romney ewes in one flock were examined after weaning. Ninety-one (5%) had clinical mastitis and, of these, 18 (1%) had hard udder. Defects detected by ultrasound scanning (later confirmed by gross and histopathological examination) included abscesses and fluid accumulations in gland cisterns. Four months after weaning (2-3 months after diagnosis with mastitis) udders of 57 of the 91 culled mastitic ewes, randomly selected, were examined. Teat and gland parenchyma from 50 of these were later assessed histopathologically. Common findings were abscesses involving gland parenchyma and teats, pus in teat cisterns, mucosal polyps associated with lymphocytic inflammation in teat cisterns leading to stenosis or atresia, and mild-to-moderate lymphocytic inflammation in the gland interstitium. Results indicate that a significant proportion of ewes with severe and/or permanent mastitis damage such as hard udder can be identified by palpation and ultrasound soon after weaning, but some signs, notably hard udder, had disappeared by the time of post-mortem 2-3 months later.

SW, Peterson, MG Collett, EBG Kennedy, AJ Molenaar, and B Nieper

New Zealand Journal of Animal Science and Production, Volume 82, Online, 57-63, 2022