Thirty-two farms (n=535cows) located in the state of Guanajuato, Mexico, were sampled. Pathogens from bovine subclinical mastitis (SCM) and clinical mastitis (CLM) were identified by 16S rDNA and the sensitivity to both antibiotics and bacteriocins ofBacillus thuringiensiswas tested. Forty-six milk samples were selected for their positive California Mastitis Test (CMT) (≥3) and any abnormality in the udder or milk. The frequency of SCM and CLM was 39.1% and 9.3%, respectively. Averages for test day milk yield (MY), lactation number (LN), herd size (HS), and number of days in milk (DM) were 20.6 kg, 2.8 lactations, 16.7 animals, and 164.1 days, respectively. MY was dependent on dairy herd (DH), LN, HS, and DMP<0.01, and correlations between udder quarters from the CMT were around 0.49P<0.01. Coagulase-negative staphylococci were mainly identified, as well asStaphylococcus aureus,Streptococcus uberis,Brevibacterium stationis,B. conglomeratum, andStaphylococcus agnetis. Bacterial isolates were resistant to penicillin, clindamycin, ampicillin, and cefotaxime. Bacteriocins synthesized byBacillus thuringiensisinhibited the growth of multiantibiotic resistance bacteria such asS. agnetis,S. equorum,Streptococcus uberis,Brevibacterium stationis, andBrachybacterium conglomeratum, but they were not active againstS. sciuri, a microorganism that showed an 84% resistance to antibiotics tested in this study.

Guzmán-Rodríguez JJ, et al. J Vet Sci. 2019 Oct;21:e77. https://doi.org/10.4142/jvs.2020.21.e77

Dirofilaria repens is the causative zoonotic agent of subcutaneous dirofilariosis. Although the American continent is considered currently free of D. repens infections, in the past few years there have been some reports suggesting the presence of this agent in the Americas. In Guanajuato, Mexico, there is a report of the presence of D. repens. To determine whether this parasite is really present in Guanajuato, a total of 177 EDTA blood samples from dogs were tested using the modified Knott's technique. Using this technique, we found 15 positive samples, which were then analyzed using the PCR technique, with a panfilarial set of primers and a specific primer pair for D. repens. In one sample, the expected band was present and the corresponding amplicon, sequenced, displayed a 100% identity to D. repens, confirming the presence of this exotic and zoonotic filarial species in the municipality of Silao, Guanajuato, Mexico.

Se presentan los principales parámetros productivos, reproductivos y de manejo de los tres principales tipos de sistemas de producción bovinos lecheros que existen en México. La importancia de mostrar el valor con número de cada parámetro permitirá al lector observar que existen diferencias en la forma de producir leche de bovino en México. Además, cada sistema se adapta a la región agroecológica donde se localiza. La información del presente manuscrito compara los sistemas de producción de leche de bovinos. Las diversas estrategias de manejo alimenticio y reproductivo en estos sistemas permiten producir de manera eficientemente para ser competitivos dentro de una economía mundial globalizada, enfrentando el reto de ser sustentables, por otro lado, mitigar los efectos que la ganadería en el cambio climático.