Significant rising antibody titres to influenza A are associated with an acute reduction in milk yield in cattle.
Sporadic cases of an acute fall in milk production, "milk drop", were investigated in a Holstein Friesian dairy herd in Devon. The investigation was a case control study with two controls per case. Paired blood samples demonstrated that rising antibody titres to human influenza A/England/333/80 (H1N1) and human influenza A/Eng/427/88 (H3N2) were associated with an acute fall in milk production. Rising titres to bovine respiratory syncytial virus (BRSV), bovine virus diarrhoea virus (BVD), infectious bovine rhinotracheitis (IBR) and parainfluenza virus 3 (PI3) were not associated with an acute fall in milk production. Cases with rises in antibody to influenza A had significantly higher respiratory scores and rectal temperatures than their controls. The mean loss of milk production for the cases with rises in antibody to influenza A compared to their controls was 159.9L. This study provides further evidence that influenza A persists in cattle and causes clinical disease.
Crawshaw
Timothy R
TR
Veterinary Laboratories Agency Staplake Mount, Starcross, Exeter, Devon EX6 8PE, UK. t.r.crawshaw@vla.defra.gsi.gov.uk
Brown
Ian H
IH
Essen
Steve C
SC
Young
Stuart C L
SC
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D002417:Cattle; D004739:England; D005260:Female; D009980:Influenza A virus / Q000276:immunology*; D007774:Lactation / Q000276:immunology*; D008892:Milk; D009976:Orthomyxoviridae Infections / Q000276:immunology / Q000662:veterinary*
D000914:Antibodies, Viral