116. A study of mastitis in Irish sheep

Clinical mastitis in ewes; bacteriology, epidemiology and clinical features

“…The very low percentage of M. haemolytica in the clinically affected glands in this study (1.8%) contrasts results of clinical mastitis surveys in meat sheep in the UK and Ireland, where the proportions of cases caused by this organism were found to be approximately 50% and 21%, respectively [ 5 , 18 ]. Enterobacteria, mainly E. coli , were obtained from 7.3% of the clinically affected udder halves, which is similar to the proportions found in other studies on meat sheep [ 5 , 18 , 22 ]. However, the number of clinical cases caused by Gram negative bacteria and A. pyogenes may be underestimated because the samples were frozen before bacteriological analysis [ 34 , 35 ].…”

“…This is in accordance with data from the Norwegian Sheep Recording System [ 36 ]. Likewise, studies in the UK and Ireland found that cases of acute clinical mastitis occurred most frequently during the first week of lactation, while a second peak occurred between the third and fourth week [ 5 ] or the fourth and seventh week [ 18 ] after lambing. Clinical cases around parturition might be newly acquired IMI or aggravations of existing subclinical infections [ 37 ].…”

“…S. aureus has been reported to be the most common causal organism in both meat [ 5 , 15 , 17 - 19 ] and dairy ewes [ 13 , 20 , 21 ]. Mannheimia haemolytica [ 5 , 18 , 19 , 22 ], Escherichia coli [ 13 , 18 , 19 ] and various streptococci [ 15 , 18 , 19 ] are other important causative organisms.…”

Breeding for resistance to mastitis in United Kingdom sheep, a review and economic appraisal

“…In meat sheep, culling due to mastitis in Rambouillet sheep after one lactation in the usa was reported to be 46 per cent (McFarland and others 2000b, Kretschmer and others 2007), and in the uk between 13 per cent and 50 per cent of ewes were reported to have udder lesions indicative of mastitis after inspection at the abattoir (Bocklisch and Wetzstein 1994). In a study of Irish ewes over three years, the incidence of acute clinical mastitis was reported to be 0·53 per cent, and the incidence of chronic subclinical mastitis was 2·8 per cent of ewes (Onnash and others 2003). In the uk , Watkins and others (1991) reported the results from 2092 milk samples that had been collected at three-weekly intervals from 358 ewes.…”

“…A review of five studies, by Bergonier and others (2003), showed that the majority of cases of mastitis occurred from the beginning of machine milking and during the first third of lactation. Other studies have reported mastitis occurring from the first week postpartum (Onnash and others 2003) to three weeks after drying off (Saratsis and other 1998); according to Bergonier and others (2003) mastitis at drying off is unusual, and caused mainly by different pathogens related to poor environmental hygiene.…”