El objetivo del estudio fue caracterizar los componentes del sistema de producción (SP) bovino doble propósito (DP) en el Distrito de Desarrollo Rural (DDR) 151 y determinar la tipología de las unidades de producción (UP) dentro del SP DP, usando variables sociales, económicas y tecnológicas. Se analizó información de 46 UP del SP DP que participaron en el programa soporte de la Secretaría de Agricultura, Ganadería, Desarrollo Rural, Pesca y Alimentación (Sagarpa) 2013-2014. A través del uso de análisis de conglomerado y análisis de varianza fueron identificados y caracterizados tres tipos de UP: Tradicional (44%), Transición (30%) y Empresarial (26%). Las UP Empresarial se diferenciaron (p < 0.05) de las de tipo Tradicional y en Transición por poseer mayor superficie, número de vacas, volumen de producción de leche e índice tecnológico, circunstancias que les permitieron obtener mayores ingresos por venta de leche y becerros.

Introduction: The cow-calf system consists of the production of calves, which will then be fattened for meat production. The state of Tabasco a high percentage of farmers are engaged in this activity, however, most of the technology transfers are focused on the dual purpose system, which has not allowed to make significant improvements in the productive variables of the cow-calf system. The objective of this study was to characterize the cow-calf system and identify the factors that affect the production of calf in the State of Tabasco.                     Method: Therefore, 342 farmers were interviewed through a structured survey to get information about the farmer date, social characteristics, infrastructure, herd structures, management practices and productive. To identify the types of farmers, a cluster analysis was performed by the Ward method and Euclidean square distance, and to identify the variables that explain the production of calves, a linear regression analysis.Results: The cluster analysis identified three types of farmers (small, medium, and large). 63.40% of the farmers were classified as small (<of 14 cows in production), 29.0% as medium (between 15 and 34 cows in production) and 7.60% as large producers (between 35 and 80 cows in production). In the three types of farmers the number of cows in production, index of adoption of technology and quantity of concentrated feed explain the production of calf.Discussion or Conclusion: The characterization of the cow-calf system of tropical regions is important because more than half of the livestock in these regions use this system of production. In addition, knowing the factors that determine the production of calf can help generate strategies for the support of this type of farmers and improve the productive variables of the system.

Milk fat from bovine milk contains fatty acids that may have favourable properties for human health, for example, conjugated linoleic acid (CLA) has nutraceutical activity. This research aimed to know the effects of genotype, days of lactation and climatic factors on the fatty acids (FA) profile of milk and particularly the content of CLA in milk fat. Seventeen first-calving milking cows in early lactation were used for the assessment of milk; 12 were Gyr and five were F1 (Holstein/Gyr) crosses. Sampling was carried out every 15 days, from the beginning to the end of lactation (300 days). Fatty acids were analyzed employing gas chromatography. The genotype did not influence the content of the fatty acid groups: saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA) and CLA. The highest MUFA and PUFA contents were recorded at 100 days of lactation (32.334 and 3.553 g/100 g of FA, respectively), while SFA and CLA had their highest production at 200 days of lactation (63.238 and 1.378 g/100 g of FA, respectively). Regarding the climate, the highest temperature caused a decrease in the CLA content, because temperatures above 30 °C caused a decrease in the grazing time.

El isómero trans-10, cis-12 del ácido linoleico conjugado se asocia con disminución en la concentración de grasa láctea. Lo cual es perjudicial para la industria lechera debido a un menor rendimiento de subproductos, por lo que el productor recibe un pago menor por la venta de leche. Sin embargo, complementar la dieta de vacas lactantes con dosis controladas del isómero trans-10, cis-12 del ácido linoleico conjugado podría reducir la demanda de energía en momentos en que la ingesta de nutrientes es insuficiente. De tal manera que la energía no utilizada para la síntesis de grasa láctea, fuese usada para mejorar el balance energético de la vaca, y ello derivará en aumento en la producción o cambios en componentes de la leche.

Objective. To determine the prevalence of antibodies against Neospora caninum (PSA) in beef and dual-purpose cattle from the Central and Southern Gulf of Mexico regions, as well as to evaluate its association with the reproductive status (RS) of the cow (pregnant, not pregnant). Materials and methods. Blood samples were taken from 422 cows. Antibodies were detected with a commercial ELISA kit. PSA was analyzed with a logistic regression model that included state, township nested within state, and ranch nested within township. Results. The states of Tabasco, Puebla and Veracruz had similar PSA (p>0.05). The mean PSA for the three states was 24.0%. The PSA varied from 7.8 to 43.3% across townships. In Puebla, the PSA in cattle from San José Acateno township was more than two-fold greater than that in cattle from Hueytamalco and Nauzontla townships (p<0.05). In Tabasco, Cunduacán, Huimanguillo and Ranchería El Puente townships showed similar (p>0.05) PSA. In Veracruz, cows from Cotaxtla and Medellín de Bravo townships presented higher (p<0.05) PSA than those from San Rafael township. The RS of seropositive females was similar (p>0.05) to that of seronegative females. Conclusions. The three states had similar PSA. All the herds had antibodies against N. caninum, suggesting that this parasite is amply distributed in the three states. In addition, great variation existed among herds and among townships; finally, the presence of N. caninum antibodies was not associated with the RS of the cow.