Resumo

ITURRALDE-GARCIA, RD et al. Activity of three essential oils on the mortality of Rhyzopertha dominica (F.) in stored wheat. Biotecnia [online]. 2022, vol.24, n.1, pp.79-86.  Epub 13-Jun-2022. ISSN 1665-1456.  https://doi.org/10.18633/biotecnia.v24i1.1552.

The objective of this study was to determine the prevalence of subclinical mastitis in dual-purpose cattle under grazing conditions through milk microbiology, and its association with serum levels of vitamins E and A in ranches located in the central region of Sonora México, during the summer where temperatures exceed 40 ° C. Milk samples were collected from the four quarters of 126 cows, for microbiological culture, including evaluation of catalase, coagulase, and oxidase activity. The isolates were tested for antimicrobial sensitivity by the Kirby-Bauer method (disk-diffusion on agar). Vitamin A and E were analyzed by HPLC. Temperature and relative humidity index (THI) were measured by relating ambient temperature and relative humidity. Mastitis prevalence was 65.80%, and the presence of Gram-positive species in clusters, coagulase and catalase-positive and oxidase negative, suggests the presence of Staphylococcus sp. Furthermore, the highest resistance found was against the ceftriaxone antibiotic. Serum values of vitamin A and E, 0.59 and 5.58 µmol/L respectively, were lower than normal values, and did not correlate with mastitis. The animals were under moderate heat stress (THI ≥80). We conclude a high prevalence of subclinical mastitis not associated with vitamins and deficiencies of vitamins E and A in summer.

Palavras-chave : Mastitis; Vitamin A; Vitamin E; Milk Microbiology; Summer.

        · resumo em Espanhol     · texto em Espanhol     · Espanhol ( pdf )