PREVALENCE OF SUBCLINICAL MASTITIS AND ASSOCIATED RISK FACTORS IN DOUBLE-PURPOSE COWS OF SMALL-SCALE PRODUCERS IN THE MEXICAN TROPICS

• DOI: https://doi.org/10.22533/at.ed.9735725291010

• Palavras-chave: risk factors, mastitis, cows.

• Keywords: risk factors, mastitis, cows.

• Abstract:

  The objective was to determine the prevalence of subclinical mastitis and associated risk factors in dual-purpose cows on small farms.  Twenty farms were studied, of which 50% (10) used manual milking and the remainder used mechanical milking, with between eight and 63 cows per producer.  The California Mastitis Test (CMT) was applied once per quarter just before milking to identify healthy and diseased animals.  The CMT was performed on 501 cows to assess prevalence. The results were: negative, 1, 2, and 3. A 2×2  contingency table was used, using the Chi-square test (P≤0.05). Mastitis positivity was taken as the independent variable and the following as the dependent variables: ranch, udder quarters, type, number of milkings, and breed. Simultaneously, the odds ratio was calculated with a 95% confidence interval. A prevalence of 9.5% was detected in manually milked cows compared to 31.4% in mechanically milked cows (P≤0.05).  Risk factors associated with subclinical mastitis were number and type of mechanical milkings per day (odds ratio: OR= 2.8 to 4.3), right anterior udder quarter (OR=1.46), farms with more than 60 milking cows (OR=1.9), and Holstein cows (OR=2.8).  Therefore, good management practices should be taken into account as control and prevention measures.