Mastitis Control Program: Effect on Milk Production

Abstract

A 3-year study of 24 commercial dairy herds measured the value of hygiene (teat dipping in 4% chlorine) and dry cow therapy (1 million units penicillin, 1 gram dihydrostreptomycin) in the reduction of infection and change in milk production. Infection dropped from 28.1% to 7.1% of the quarters. Herds on the mastitis control program produced an average of 477 kg of milk per cow more per year for each of the 3 years than the average New York Dairy Herd Improvement herd after adjustment for differences in initial production. A least squares analysis determined factors associated with mastitis that have the greatest effect on milk production. Presence of organisms in the udder caused the greatest decrease in milk production while the genus of organism affected the loss. Quarters infected with Staphylococcus aureus produced approximately 760 kg less milk per lactation than uninfected quarters. Quarters harboring other organisms, including some regarded as nonpathogenic, produced more than 500 kg of milk less per lactation than uninfected quarters. Quarters infected with more than one pathogen at the same time had an additional decrease in production. Reduction in milk production was most severe when infections began during early lactation. However, infections that lasted less than 40 weeks caused a greater decrease in milk production than those lasting longer.