No abstract

Parasites are one of the most important threats to domesticated livestock worldwide. For several decades, their control has been based only on therapeutic interventions using chemical products at fixed intervals throughout the year. Results have demonstrated that dependence on these chemical products, as a single form of control, is not economically and ecologically sustainable. The problem has been augmented due to the emergence of endoparasite and ectoparasite populations resistant and multiresistant to the primary families of chemical products used to control them. Yet, these chemicals continue to be overused as the primary method for parasite control. Even more, their toxicity to animals, environmental contamination, and economic cost are of increasing concern. This limited approach to parasite control has environmental consequences with likely negative impacts to human and animal health. For example, most endectocides used to control parasites (endoparasites and ectoparasites) in domesticated animals are eliminated in the milk produced by females. Thus, there is strong concern regarding human consumption of dairy products containing such chemicals. Currently, market demands focus on healthy livestock production with emphases on the high standards in animal health and welfare based on quality production practices. The sustainable production of domesticated livestock needs strong changes, such as considering agroecologically oriented as well as novel approaches for parasite control. Thus, the use of existing drugs should be more strategically implemented and combined with other nonchemical alternatives for ruminant livestock. New strategies for controlling parasites in ruminant livestock should begin with the premise of not eliminating or eradicating parasitic organisms, but instead basing actions on economic thresholds (similar to IPM strategies for agricultural crops). In this review, we discuss the problem and current situation regarding parasites and their control using ranching operation methods. We discuss regions where the problem of chemical resistance is of strong concern and include the ecological and socioeconomic effects of parasite control (or lack therefore). We present information about novel approaches such as improving the nutritional status of the host and biological control methods for integration with domestic livestock in order to decrease the use of and reliance on chemical products.

Introducción. El uso de antihelmínticos (AH) para el control de nematodos gastrointestinales (NGI) en caprinos se ve amenazado por el surgimiento de cepas de NGI resistentes a AH. No existe información de la presencia de NGI resistentes en rebaños caprinos de México y Yucatán. El objetivo fue determinar la presencia de NGI resistentes a bencimidazoles (BZ), imidazotiazoles (LEV) y lactonas macrocíclicas (LM) en un rebaño caprino de Yucatán, México, mediante la prueba de reducción de cuentas de huevos fecales. Material y métodos. La presencia de nematodos resistentes a BZ, LEV y LM fue determinada mediante la prueba de reducción de cuentas de huevos fecales. La técnica de conteo de huevos fecales de McMaster modificada se utilizó para seleccionar sesenta cabras adultas con más de 150 huevos por gramo de heces (HPG). Estos animales fueron distribuidos al azar en cuatro grupos de 14 ó 15 animales. El grupo 1 permaneció sin tratamiento AH (T). El grupo 2 fue tratado con BZ (7.6mg/kg de peso vivo (PV) de albendazol per os). El grupo 3 con LEV (12mg/kg de PV de levamisol por vía subcutánea) y el grupo 4 con LM (0.2mg/kg de PV de moxidectina por vía subcutánea). Los animales fueron pesados individualmente y las drogas fueron administradas de acuerdo al peso. Los animales fueron aislados de alimento durante 16 horas antes del tratamiento AH. Todos los animales fueron muestreados nuevamente el día 12 post-tratamiento. Los resultados de HPG del segundo muestreo se usaron para determinar el porcentaje de reducción de HPG (%R) y el intervalo de confianza 95% (IC95%). Se realizó un cultivo fecal por cada grupo estudiado para identificar los géneros de larvas en una muestra de cincuenta larvas infectantes de cada grupo. Resultados. No se encontró resistencia contra LM en el rebaño estudiado. Se encontraron NGI resistentes a BZ (%R=89, IC95%=77-94) y LEV (%R=82, IC95%=59-92). Haemonchus spp. fue el género de NGI resistente a BZ. Los géneros resistentes a LEV fueron Trichostrongylus spp. (96%) y Oesophagostomun spp. (4%). Discusión. La presencia de NGI resistentes a LEV y BZ pudo ser causada por varios años de uso de dosis sub-terapéuticas de ambos AH en el rebaño. Estas dosis sub-terapéuticas fueron obtenidas de la etiqueta de las drogas utilizadas. La falta de rotación anual de drogas en el rebaño pudo haber contribuido al desarrollo de resistencia.

This study was conducted to identify the information acquisition sources of backyard chicken production practices amongst rural women in Yucatan. Focus group discussions (FGDs) and face-to-face individual interviews with a predesigned questionnaire were employed for collecting data from two rural villages. Within each village, three focus group sessions of Mayan women were held involving 10-12 participants each. Participants were selected according to their skills level of backyard chicken practices. The results revealed that family, friends/neighbors, own-personal experience and feed suppliers were significantly the most important information sources used by rural women. Concerning the preferred sources by participants; extension agents, trainers/ specialists, family, demonstrations methods, veterinarian and friends/neighbors were significantly the most preferred sources. The technical areas of backyard chicken production which women received information about were feeds and feeding, housing systems, diseases control, marketing and reproduction. Findings also showed that unavailability of extension agents and cost of veterinary services were the most important constraints affecting information acquisition. The most important recommendations were the need for extension services and training programs as modern information sources for improving their managerial skills and knowledge on backyard chicken production practices.Key words: backyard chicken, group discussions, information acquisition sources, production practices. resumenEste estudio se llevó a cabo para identificar las fuentes de adquisición de información sobre las prácticas de producción de pollo entre las mujeres rurales en Yucatán. Se utilizaron discusiones en grupos de foco (DGF) y entrevistas individuales frente a frente con un cuestionario prediseñado para recolectar datos de dos pueblos rurales. Dentro de cada pueblo, se realizaron tres sesiones de grupo de foco con mujeres mayas, involucrando a 10-12 participantes en cada una. Las participantes se seleccionaron con base en su nivel de habilidad en las prác-ticas de producción de pollo de traspatio. Los resultados revelaron que la familia, los amigos/vecinos, su propia experiencia personal y los proveedores de alimento fueron las fuentes de información más importantes utilizadas por las mujeres rurales. Respecto a las fuentes preferidas por las participantes, los agentes de extensión, los capacitadores/especialistas, la familia, los métodos de demostración, los veterinarios y los amigos/ vecinos fueron las fuentes más preferidas, significativamente. Las áreas técnicas de producción de pollo de traspatio sobre las que las mujeres recibieron información fueron alimentos y alimentación, sistemas de alojamiento, control de enfermedades, mercadotecnia y reproducción. Los resultados también mostraron que la poca disponibilidad de los agentes de extensión y el costo de los servicios veterinarios fueron los limitantes más importantes que afectaron la adquisición de información. Las recomendacione...

SummaryThe objective was to highlight the role of supplementary feeding on resilience and resistance of browsing small ruminants against natural gastrointestinal nematode (GIN) infections. GIN infections have a negative impact on productivity of browsing Criollo kids especially during the wet season of Yucátan. Epidemiological studies have demonstrated the threat of GIN infectivity in the native vegetation available for browsing goats. Control of GIN in browsing ruminants is threatened by the emergence of anthelmintic resistant nematodes strains in the local flocks. Browsing trials with kids and lambs have shown that supplementary feeding (100–108g/day) improved resilience and resistance of Criollo kids against GIN. Supplements used successfully include sorghum:soybean meal (74:26 respectively), maize:soybean meal (74:26) and maize only (108g/day). The later result showed that animals might benefit from supplementation with rumen fermentable energy that could improve utilization of available browsing legumes by the goats. Wet season trials showed that, in spite of supplementation, infected animals have lower productivity compared to non-infected animals. However, the combined use of supplementation and copper oxide wire particles or tactic anthelmintic treatment, can improve growth rate of infected kids to maximum production levels. Short-term supplementation strategies have shown to be less effective than long-term strategies in achieving better resilience against GIN in kids. Lambs are more resistant but less resilient against GIN infections than kids. Improved resistance of lambs seemed to require more nutrients than in goats. In conclusion, supplementary feeding can play an important role in improving both resilience and resistance of growing small ruminants in the tropics but it can be further improved through the complementary use of other strategies leading to a more sustainable integrated parasite control strategy.