Associations between small ruminant lentivirus infection and total milk yield and somatic cell count in a dairy sheep flock

Davies, Peers ORCID: 0000-0001-6085-9763, Jones, Scott, Dunham, Stephen and Tarlinton, Rachael EE (2023) Associations between small ruminant lentivirus infection and total milk yield and somatic cell count in a dairy sheep flock. VETERINARY RECORD, 192 (11). e2731-.

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Official URL: http://dx.doi.org/10.1002/vetr.2731

Abstract

<h4>Background</h4>Small ruminant lentiviruses (SRLVs) are lentiviruses of sheep and goats, formerly known as maedi-visna (MV) in sheep and caprine encephalitis and arthritis in goats. In sheep, SRLVs commonly cause progressive pneumonia, wasting and indurative mastitis. SRLVs have a long latent period, and chronic production losses are often not recognised until very late. Few studies quantifying the production losses in ewes have been published, and none have been published under UK flock husbandry conditions.<h4>Methods</h4>Production records of milk yield and somatic cell count (SCC) from a dairy flock of 319 milking East Friesian × Lacaune ewes identified as MV infected via routine serological screening for SRLV antibodies were used in multivariable linear regression modelling to estimate the impact of SRLV status on total milk yield and SCC.<h4>Results</h4>Milk yield was reduced in seropositive ewes by 8.1%-9.2% over an entire lactation. SCC counts were not significantly different in SRLV-infected and unifected animals.<h4>Limitations</h4>Further parameters, such as body condition score or clinical mastitis, that were not available may have clarified the underlying cause of milk yield drop.<h4>Conclusions</h4>The study demonstrates substantial production losses in an SRLV-affected flock and highlights the impact of the virus on a farm's economic viability.

Item Type:	Article
Uncontrolled Keywords:	Maedi-Visna, milk, sheep, small ruminant lentivirus
Divisions:	Faculty of Health and Life Sciences Faculty of Health and Life Sciences > Institute of Infection, Veterinary and Ecological Sciences
Depositing User:	Symplectic Admin
Date Deposited:	03 May 2023 14:57
Last Modified:	26 Jul 2023 13:18
DOI:	10.1002/vetr.2731
Open Access URL:	https://doi.org/10.1002/vetr.2731
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3170128