Longitudinal study of the effect of sporidesmin toxicity on lamb production and serum biochemistry in a flock of 46 Romney ewes using a standardised measure of liver damage.

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dc.contributor.authorLawrence KE
dc.contributor.authorFlay KJ
dc.contributor.authorMunday JS
dc.contributor.authorAberdein D
dc.contributor.authorThomson NA
dc.contributor.authorVignes M
dc.contributor.authorRidler AL
dc.date.available2022-03-01
dc.date.issued2022-07
dc.descriptionCAUL Read and Publish Agreement.
dc.description.abstractAIMS: To evaluate the effect of sporidesmin toxicity on production outcomes and serum biochemistry analytes in mixed age Romney ewes, using a standardised measure of liver damage. METHODS: This was a prospective longitudinal study following 46 mixed age Romney ewes from sporidesmin intoxication in April 2019, to slaughter 8 months later. The ewes were blood-sampled up to eight times, with a panel of serum biochemistry tests performed on the final six samples. However, only gamma-glutamyl transferase (GGT) activity was measured in the first two samples collected at the end of sporidesmin intoxication and 2 weeks later. Body condition score, ewe weight and production data were also recorded. Using a standardised liver score, based on histology of liver samples collected at slaughter, ewes were assigned to one of three liver disease categories (LDC); low, middle, and high. These were then used as the outcome or predictor variables for statistical analyses. Finally, two separate decision tree models, using recursive partitioning (RP), were fitted to the biochemistry data and to the GGT data collected at FE outbreak, to predict ewes in the low LDC. RESULTS: There was no evidence of a difference for the effect of LDC on ewe weight (p = 0.86) with ewes, on average, gaining weight to weaning. Weaning percent, lamb rearing percent and ewe flock efficiency were lower in ewes with high LDC, and scanning-to-weaning lamb loss was significantly higher in sheep with high LDC (p = 0.02). Serum activities of GGT and glutamate dehydrogenase and concentration of globulin were significantly lower in sheep with low LDC than in sheep with middle or high LDC (p < 0.05). However, there was no evidence of a difference for the effect of LDC on other biochemistry variables (p > 0.05). The final RP model for the biochemistry data categorised ewes as low LDC if their GGT was <122 IU/L, 3 months after sporidesmin intoxication, or if their GGT was <514 IU/L, <18 days after sporidesmin intoxication. CONCLUSIONS AND CLINICAL RELEVANCE: Sheep with gross and histological evidence of severe sporidesmin-induced liver damage were able to maintain or gain body weight, suggesting that sporidesmin intoxication alone is not causative of poor body condition. Similarly, many of the serum biochemistry tests were not associated with evidence of liver damage. Lamb production was reduced in ewes with evidence of severe liver damage and the decision tree model showed promise as a basis to select ewes for culling.
dc.description.publication-statusPublished
dc.identifierhttp://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000765621800001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=c5bb3b2499afac691c2e3c1a83ef6fef
dc.identifier.citationNEW ZEALAND VETERINARY JOURNAL, 2022
dc.identifier.doi10.1080/00480169.2022.2042414
dc.identifier.eissn1176-0710
dc.identifier.elements-id451181
dc.identifier.harvestedMassey_Dark
dc.identifier.issn0048-0169
dc.relation.isPartOfNEW ZEALAND VETERINARY JOURNAL
dc.rights(c) The author/s CC BY CC BY-NC-ND
dc.subjectSheep
dc.subjectNew Zealand
dc.subjectFacial Eczema
dc.subjectSporidesmin
dc.subjectLiver damage
dc.subjectGamma-glutamyl transferase
dc.subject.anzsrc0707 Veterinary Sciences
dc.titleLongitudinal study of the effect of sporidesmin toxicity on lamb production and serum biochemistry in a flock of 46 Romney ewes using a standardised measure of liver damage.
dc.typeJournal article
pubs.notesNot known
pubs.organisational-group/Massey University
pubs.organisational-group/Massey University/College of Sciences
pubs.organisational-group/Massey University/College of Sciences/School of Mathematical and Computational Sciences
pubs.organisational-group/Massey University/College of Sciences/School of Veterinary Science
pubs.organisational-group/Massey University/Other
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