Incidence and Treatments of Bovine Mastitis and Other Diseases on 37 Dairy Farms in Wisconsin

Abstract

The aim of this research was to describe the incidence and treatments of mastitis and other common bovine diseases using one year of retrospective observational data (n = 50,329 cow-lactations) obtained from herd management software of 37 large dairy farms in Wisconsin. Incidence rate (IR) was defined as the number of first cases of each disease divided by the number of lactations per farm. Clinical mastitis (CM) remains the most diagnosed disease of dairy cows. Across all herds, the mean IR (cases per 100 cow-lactations) was 24.4 for clinical mastitis, 14.5 for foot disorders (FD), 11.2 for metritis (ME), 8.6 for ketosis (KE), 7.4 for retained fetal membranes (RFM), 4.5 for diarrhea (DI), 3.1 for displaced abomasum (DA), 2.9 for pneumonia (PN) and 1.9 for milk fever (MF). More than 30% of cows that had first cases of CM, DA, RFM, DI, and FD did not receive antibiotics. Of those treated, more than 50% of cows diagnosed with PN, ME and CM received ceftiofur as a treatment. The IR of mastitis and most other diseases was greater in older cows (parity ≥ 3) during the first 100 days of lactation and these cows were more likely to receive antibiotic treatments (as compared to younger cows diagnosed in later lactation). Cows of first and second parities in early lactation were more likely to remain in the herd after diagnosis of disease, as compared to older cows and cows in later stages of lactation. Most older cows diagnosed with CM in later lactation were culled before completion of the lactation. These results provide baseline data for disease incidence in dairy cows on modern U.S. dairy farms and reinforce the role of mastitis as an important cause of dairy cow morbidity.

Keywords: antibiotic; antimicrobial; dairy; disease; epidemiology.

Figure 1

The median incidence rate (cases per 100 cow-lactations) of bovine diseases from 37 WI dairy herds in 2017. Incidence rate was defined as the number of first cases of each disease divided by the number of lactations per farm. CM = clinical mastitis; ME = metritis; KE = ketosis; RFM = retained fetal membranes; FD = foot disorders; DA = displaced abomasum; PN = pneumonia; MF = milk fever and DI = diarrhea.

Figure 2

Incidence rate of diseases (clinical mastitis, displaced abomasum, diarrhea and foot disorders) with interaction of parity and stage of lactation for 37 WI dairy herds in 2017. Different superscripts letters (e.g., a–h) indicate comparisons among stages of lactation within parity and disease were significant (p < 0.004).

Figure 3

Frequency of retention in the herd after a disease case (clinical mastitis, displaced abomasum, and diarrhea) with interaction factor of parity and stage of lactation for 37 WI dairy herds in 2017. Different letters mean the comparison among stages of lactation within parity and disease were significant (p < 0.003).