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/Eng/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 159.9 litres. This study provides further evidence that influenza A persists in cattle and causes clinical disease.
|Number of pages||5|
|Publication status||Published - 01 Nov 2007|