FACTORS ASSOCIATED WITH MASTITIS IN ONTARIO DAIRY HERDS - A CASE CONTROL STUDY

  • 1 January 1980
    • journal article
    • research article
    • Vol. 44  (4) , 351-357
Abstract
Data from Ontario dairy cattle herds which had a high average milk gel index for 1978 (cases) and from other herds which had a low average during the same period (controls) were collected and analyzed using case-control techniques. The purpose of the study was to contrast factors of husbandry and management between the 2 groups and to determine the relative contribution of each of these factors on mastitis (as determined indirectly by the milk gel index) at the herd level. Control herds had higher average production levels than did case herds, shipping 1807 l more milk/cow per year. Milk from control herds averaged 0.06% higher in butterfat, 0.19% higher in lactose and 0.05% lower in total protein. Many factors can influence production, therefore these latter differences in both shipped milk and composition, cannot be attributed solely to differences in the prevalence of mastitis between the 2 groups. Control herds were more likely to use teat dip, receive regular veterinary service, use dry cow antiboitic preparations and have knowledge concerning subclinical mastitis than were case herds. Control herds also tended to raise more of their own replacements, have a higher culling rate for reasons of low production and have a more modernized dairy operation. Case herds were more likely to scrutinize foremilk, use more milking units per operator and wait longer between the start of stimulation and attachment of the milking unit. The study confirms, under natural field conditions, the importance of integrated mastitis control practices and also reaffirms the relative importance of practices such as the use of teat dips and dry cow antibiotic preparations.