title: A cross-sectional study of 329 farms in England to identify risk factors for ovine clinical mastitis.
abstract: The aims of this study were to estimate the incidence rate of clinical mastitis (IRCM) and identify risk factors for clinical mastitis in suckler ewes to generate hypotheses for future study. A postal questionnaire was sent to 999 randomly selected English sheep farmers in 2010 to gather data on farmer reported IRCM and flock management practices for the calendar year 2009, of which 329 provided usable information. The mean IRCM per flock was 1.2/100 ewes/year (CI:1.10:1.35). The IRCM was 2.0, 0.9 and 1.3/100 ewes/year for flocks that lambed indoors, outdoors and a combination of both, respectively. Farmers ran a variety of managements before, during and after lambing that were not comparable within one model, therefore six mixed effects over-dispersed Poisson regression models were developed. Factors significantly associated with increased IRCM were increasing percentage of the flock with poor udder conformation, increasing mean number of lambs reared/ewe and when some or all ewes lambed in barns compared with outdoors (Model 1). For ewes housed in barns before lambing (Model 2), concrete, earth and other materials were associated with an increase in IRCM compared with hardcore floors (an aggregate of broken bricks and stones). For ewes in barns during lambing (Model 3), an increase in IRCM was associated with concrete compared with hardcore flooring and where bedding was stored covered outdoors or in a building compared with bedding stored outdoors uncovered. For ewes in barns after lambing (Model 4), increased IRCM was associated with earth compared with hardcore floors, and when fresh bedding was added once per week compared with at a frequency of ≤2 days or twice/week. The IRCM was lower for flocks where some or all ewes remained in the same fields before, during and after lambing compared with flocks that did not (Model 5). Where ewes and lambs were turned outdoors after lambing (Model 6), the IRCM increased as the age of the oldest lambs at turnout increased. We conclude that the reported IRCM is low but highly variable and that the complexity of management of sheep around lambing limits the insight into generating hypotheses at flock level for risks for clinical mastitis across the whole industry. Whilst indoor production was generally associated with an increased IRCM, for ewes with large litter size indoor lambing was protective, we hypothesise that this is possibly because of better nutrition or reduced exposure to poor weather and factors associated with hygiene.
authors.affiliation: School of Life Sciences, University of Warwick, Coventry CV4 7AL, England, United Kingdom. Electronic address: selin.cooper@warwick.ac.uk.
authors.forename: S
authors.initials: S
authors.lastname: Cooper
authors.affiliation: School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Leicestershire LE12 5RD, England, United Kingdom.
authors.forename: S J
authors.initials: SJ
authors.lastname: Huntley
authors.affiliation: School of Life Sciences, University of Warwick, Coventry CV4 7AL, England, United Kingdom.
authors.forename: R
authors.initials: R
authors.lastname: Crump
authors.affiliation: School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Leicestershire LE12 5RD, England, United Kingdom.
authors.forename: F
authors.initials: F
authors.lastname: Lovatt
authors.affiliation: School of Life Sciences, University of Warwick, Coventry CV4 7AL, England, United Kingdom.
authors.forename: L E
authors.initials: LE
authors.lastname: Green
mesh_terms: D000818:Animals; D003430:Cross-Sectional Studies; D004739:England / Q000453:epidemiology; D005260:Female; D015994:Incidence; D008413:Mastitis / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D012189:Retrospective Studies; D012307:Risk Factors; D012756:Sheep; D012757:Sheep Diseases / Q000453:epidemiology* / Q000382:microbiology
keywords: Incidence rate; Ovine mastitis; Poisson regression; Risk factor
references.citation: J Dairy Sci. 1999 Aug;82(8):1643-54
references.pmid: 10480089
references.citation: J Dairy Res. 1999 Nov;66(4):489-99
references.pmid: 10612048
references.citation: J Dairy Sci. 2000 Sep;83(9):1957-65
references.pmid: 11003224
references.citation: Scand J Public Health. 2003;31(6):411-7
references.pmid: 14675932
references.citation: J Anim Sci. 1992 Jun;70(6):1677-81
references.pmid: 1634391
references.citation: Prev Vet Med. 2008 Jan 1;83(1):52-64
references.pmid: 17688961
references.citation: Acta Vet Scand. 2007 Sep 24;49:23
references.pmid: 17892567
references.citation: J Dairy Sci. 2008 Apr;91(4):1366-77
references.pmid: 18349229
references.citation: Vet Rec. 2008 Mar 22;162(12):369-76
references.pmid: 18359930
references.citation: Prev Vet Med. 2008 Nov 17;87(3-4):229-43
references.pmid: 18514940
references.citation: Prev Vet Med. 2008 Nov 17;87(3-4):373-93
references.pmid: 18656275
references.citation: Vet Microbiol. 2009 Feb 16;134(1-2):89-94
references.pmid: 18945561
references.citation: Br Vet J. 1991 Sep-Oct;147(5):413-20
references.pmid: 1959012
references.citation: J Dairy Sci. 2010 Apr;93(4):1578-86
references.pmid: 20338435
references.citation: J Dairy Sci. 2012 Sep;95(9):5001-5010
references.pmid: 22916904
references.citation: Br Vet J. 1990 Jan-Feb;146(1):43-9
references.pmid: 2306602
references.citation: Prev Vet Med. 2013 Jun 1;110(2):232-41
references.pmid: 23253147
references.citation: Am J Vet Res. 1989 Feb;50(2):207-14
references.pmid: 2541640
references.citation: Prev Vet Med. 2016 May 1;127:27-36
references.pmid: 27094137
references.citation: J Dairy Sci. 1988 Sep;71(9):2584-606
references.pmid: 3053815
references.citation: J Anim Sci. 1978 Jan;46(1):1-8
references.pmid: 565347
references.citation: Prev Vet Med. 1998 Jan;33(1-4):171-81
references.pmid: 9500172
references.citation: Age Ageing. 1998 Jan;27(1):35-40
references.pmid: 9504364
references.citation: Prev Vet Med. 1998 Dec 1;37(1-4):173-83
references.pmid: 9879590