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Improved understanding of mastitis in sheep

Research in the School of Life Sciences has increased understanding of the causative agents of, and risk factors for, mastitis in suckler ewes. Results disseminated to farmers highlight the importance of maintaining udder health and the role of nutrition during pregnancy and lactation. Current work aims to build on this by comprehensively reviewing risk factors for mastitis, developing interventions to reduce the incidence of mastitis, and characterising within-flock transmission patterns.

Background

Mastitis is usually caused by bacterial infection of the mammary gland that causes inflammation; heat, swelling and pain . Mastitis is an endemic disease, with impacts on farm sustainability and livestock health and welfare. Estimates suggest mastitis costs the UK sheep industry in excess of £120million per annum in direct and indirect costs; and it is ranked as the most important disease of suckler ewes.

Mastitis and intra-mammary infections result in reduced milk yield and quality, loss of udder function, premature culling and occasionally death of affected ewes. It impacts on the growth rate of lambs and reduces farm viability.

Impact

More than 30 bacterial species have been associated with intra-mammary infections and chronic mastitis, and the potential for transmission between affected and unaffected glands of the same and different ewes has been revealed (Smith et al., 2015). Further analysis has demonstrated the presence of a complex and dynamic microbial community (microbiome) within each gland of the udder (Monaghan 2015).

The impact of nutrition on mastitis has been identified. Insufficient protein in pregnancy increased the risk of acute mastitis four fold and feeding insufficient energy in both pregnancy and lactation doubled the risk of intramammary masses (chronic mastitis). Other factors associated with mastitis include poor udder and teat conformation (Huntley et al., 2012), housing and stocking density.

Future

AHDB Beef & Lamb are currently funding a PhD studentship at Warwick to investigate within-flock transmission routes and develop practical mastitis control mechanisms. Ultimately, the aim is to improve management of mastitis and so improve sustainability of sheep farming through reduced economic impact of disease and increased ewe longevity by improved health and welfare.


References:

Huntley, Selene J., Cooper, S., Bradley, Andrew J. and Green, Laura E.. (2012) A cohort study of the associations between udder conformation, milk somatic cell count, and lamb weight in suckler ewes.
Journal of Dairy Science, Vol.95 (No.9) 5001-5010 (PDF Document)

Monaghan, E. M. (2015) Microbial ecology of the sheep mammary gland. PhD thesis, University of Warwick

Smith, Edward M., Willis, Zoë N., Blakeley, Matthew, Lovatt, Fiona, Purdy, Kevin J. and Green, Laura E.. (2015) Bacterial species and their associations with acute and chronic mastitis in suckler ewes.
Journal of Dairy Science, Vol.98 7025-7033

Sheep Udder
Healthy udder


Research led by Professor Laura Green