Characterisation of inflammation and pain thresholds to mechanical stimulation in dairy cows with clinical mastitis and the effect of treatment with meloxicam

Recognition, alleviation and control of pain are central to ensuring good welfare in food producing animals. An intervention trial was conducted on 117 dairy cows with naturally-occurring, mild or moderate, clinical mastitis in a single quarter in order to investigate the effect of the administration of the non-steroidal anti-inflammatory drug, meloxicam (Metacam, Boehringer Ingelheim Animal Health GmbH) used in conjunction with an intramammary antibiotic infusion of cefquinome (Cephaguard LC Intramammary, Intervet UK Limited, Milton Keynes). Clinical and laboratory parameters were investigated to assess their usefulness as objective markers of pain. Measuring the cows’ response to a mechanical stimulus assessed altered pain processing. Heart rates, respiratory rates and rectal temperatures of cows were higher in moderate cases compared to milk cases of clinical mastitis (p0.05). On bacteriological examination to the recruited cases, 30% of isolates yielded S uberis, 24% yielded no growth, 22% E coli, 11% Staph aureus, six per cent other microbiological species, four per cent A pyogenes and three per cent S dysgalactiae. When compared with mild cases of mastitis the moderate cases had a greater proportion of isolations of S uberis (p<0.01) and a smaller proportion of no growths (p<0.01). There was no effect of mastitis on the fat percentage of milk, as judged by the comparison of affected quarters to diagonally opposite quarters and to normal cows. The protein content of milk increased with mastitis and the lactose content decreased. The most common somatic cell type in quarters affected with mild and moderate mastitis on the day of recruitment to the study were polymorphonuclear cells, whereas large mononuclear cells were the predominant cell type in normal animals. The concentration of haptoglobin in milk from the affected quarters of cows with moderate mastitis was greater (p<0.01) than that in milk from affected quarter of cows with mild mastitis. Mammary-associated serum amyloid A concentrations were higher in the affected quarter of cases of milk and moderate clinical mastitis than in normal cows (p<0.001). Concentrations of the inflammatory mediator, prostaglandin E2 in milk were lower in mild cases of clinical mastitis compared to moderate cases (p