Factores epidemiológicos en la prevalencia de mastitis subclínica en vacunos lecheros de pequeños productores de la irrigación “San Felipe”- Huaura

Abstract

Using The California Mastitis Test (CMT), 1080 mammary quarters from 270 cows, Holstein (94 %) and Creole or undetermined breed (6 %), and including multiparous and uniparous cows, were evaluated. The prevalence of subclinical mastitis was 21,58 %. The index of sub clinical mastitis (IMSC), an epidemiological indicator, was 0, 84, which was found to be high when compared to the ideal value of 0, 5 for this type of farming; the relationship low risk / high risk was 7, 35, which means that for each quarter at high risk there were 7, 35 quarters at low risk; this value should always be kept high, even higher than 10. Microbiological analyses were performed in 25 milk samples from mammary quarters with subclinical mastitis grade 3 from 12 milking cows. 14 samples (56 %) yielded positive culture and 11 (44 %) gave negative culture. All the microorganisms found were environmental: Staphylococcus albus (43 %), non-hemolytic Streptococcus (21 %), Escherichia coli (29 %), and Enterobacter aerogenes (7 %). A multivariate logistic regression model was used for the analysis of epidemiological variables to obtain the degree of association for the presentation of subclinical mastitis through the Odds ratio (OR) values. The risk factors with the strongest association were wet and very wet soil, which is related to the lack of hygiene in the stables, making them reservoirs of environmental pathogens.