This trial evaluated the effect of maize supplementation on the ingestive behavior, nutrient intake and the resilience against gastrointestinal nematode (GIN) infection of hair sheep in a silvopastoral system containing tropical grasses and legume trees. In addition, it attempted to determine the metabolic cost of the natural GIN infection in supplemented and non-supplemented animals. Twenty-nine 3-month-old lambs (male and female), raised nematode free, were allocated to four groups: I-NS (infected, not supplemented, n = 8), I-S (infected, supplemented with maize at 1.5% live weight (LW), n = 7), T-NS (treated with moxidectin 0.2 mg/kg LW every 28 days, and not supplemented, n = 7) and T-S (treated with moxidectin and supplemented with maize at 1.5% LW, n = 7). During the 70-day trial, fodder intake, fodder selection, LW change (LWC), red blood cell counts (RBC), hemoglobin (Hb), hematocrit (Ht) and eggs per gram of feces (EPG) were measured every 14 days. Supplement consumption was recorded daily. Metabolizable energy (ME) and protein (MP) consumption from the feeds were estimated. Maize supplementation helped to improve the resilience of hair sheep lambs against GIN infections. The I-S and T-NS groups showed similar LWC, RBC, Hb and Ht (P > 0.05) and both were higher than those in the I-NS group (P < 0.05). No difference was found in EPG between the I-NS and the I-S groups (P > 0.05). No effect of sex was observed in the different variables. Although all groups showed low dry matter intake (DMI) (< 2% LW), supplemented groups (T-S and I-S) showed higher total DMI (fodder + maize; P < 0.05), hence higher ME and MP intakes than the non-supplemented groups (T-NS and I-NS). All groups showed similar fodder selection patterns. The estimated metabolic cost of parasitism was ME = 0.70 MJ/day and MP = 9.2 g/day in the I-S animals. Meanwhile, the cost in the I-NS animals was ME = 1.46 MJ/day and MP = 12.71 g/day. Maize supplementation was an economically viable strategy to control GIN compared with no intervention.
El objetivo del estudio fue describir los sistemas intensivos de engorda de corderos en el Estado de Yucatán, México. El estudio se desarrolló de marzo a junio de 2013. Se aplicó una encuesta a productores o responsables de 34 granjas, seleccionadas por conveniencia. La información fue analizada a través de tablas de frecuencias, medidas de tendencia central y análisis de varianza obtenidos con el paquete estadístico STATGRAPHICS® Centurion XV. Los resultados mostraron que los sistemas intensivos de engorda de corderos se diferencian básicamente por dos tipos de alojamiento: a) corrales a nivel del suelo (SICS) y b) corrales elevados con piso de rejilla (SICE). Los genotipos están formados por la cruza de razas Pelibuey, Dorper y Katahdin, principalmente (93.94 %). La alimentación se basa en la utilización de concentrados de marcas comerciales (47.06 %), elaborados en la granja (47.06 %) y elaborados por proveedores informales (5.88 %). El manejo sanitario consiste en la vacunación (79.41 %) y desparasitación de los animales (100 %). Se encontró, un mejor comportamiento productivo de los corderos de engorda en SICE comparado con aquellos de SICS. La venta de corderos en pie (91.18 %) es la principal fuente de ingresos económicos, con un precio de $29.75/kg. La mayoría de los productores (67.65 %) comercializan a sus animales en la unidad de producción. Es necesario hacer una evaluación prospectiva de los SICE y los SICS desde el punto de vista productivo y económico.
Palabras clave: Ovinos, crecimiento, sistemas de alojamiento, corrales elevadosRecepción: 05-06-201505-06- Aceptación: 19-09-2015
AbstractThe aim of this study was to describe lamb fattening intensive systems in the State of Yucatan, Mexico. The study was carried out from March to June 2013. Thirty four surveys were applied to either owners or managers at the farms, selected by convenience. The information gathered was analyzed throughout frequency tables, central tendency measures, and ANOVA using the prospective studies on both productive and economic aspects of these systems.
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