Mineral requirements of hair sheep in tropical climates

Abstract

RESUMEN Los ovinos de pelo juegan un papel importante en la producción animal en las regiones tropicales; sin embargo, sus requerimientos nutricionales no se han determinado en la misma medida que los de las razas de lana. Debido a las condiciones ambientales de las regiones tropicales (clima, calidad y disponibilidad de alimentos), es razonable la hipótesis de que los requerimientos de energía metabolizable (EM) y la eficiencia de utilización de la EM pueden ser diferentes entre los ovinos de razas de pelo y de lana. La información disponible en ovinos de pelo muestra una gran discrepancia en cuanto a las necesidades de energía. Con base en datos de la literatura disponible para hembras ovinas, el requerimiento de EM para mantenimiento (EM m) fue de 419±129 kJ/kg PC 0.75 (media ± desviación estándar) y para machos fue 388±123 kJ/kg BW 0.75. El requerimiento de energía neta para la ganancia de peso (EN g) varió de 8.75 a 14.06 kJ/g (11.63±1.86 kJ/g). Las eficiencias de utilización de la EM para el mantenimiento (k m) y la ganancia de peso (k g) fueron de 0.66±0.023 y 0.42±0.044, respectivamente. Esta revisión también indicó que la información es escasa para ovejas adultas en diferentes etapas fisiológicas (mantenimiento, lactancia y gestación). Se requiere más trabajo de investigación con relación a la estimación de las necesidades de energía de los ovinos de pelo, con el fin de hacer ajustes a los modelos existentes de alimentación, con el objetivo de predecir la respuesta de los animales con la condición que prevalece en los trópicos (tipo de animal, medio ambiente y alimentos disponibles). PALABRAS CLAVE: Ovinos de pelo, Requerimientos de energía, ABSTRACT Breeds of hair sheep play an important role in animal production in tropical regions; however, their nutrient requirements have not been determined to the same extent as those of wool breeds. Due to the environmental conditions of the tropical regions (climate, quality and availability of feedstuffs), it is reasonable to hypothesize that energy requirements and efficiency of utilization of metabolizable energy (ME) may be different between hair and wool breeds of sheep. Information available on hair sheep shows a large discrepancy regarding energy requirements. Based on available literature data for female sheep, ME requirement for maintenance (ME m) was 419±129 kJ/ kgBW 0.75 (mean ± standard deviation) and for the male 388±123 kJ/kg BW 0.75. The requirement of net energy for gain (NE g) ranged from 8.75 to 14.06 kJ/g (11.63±1.86 kJ/g). The efficiency of ME utilization for maintenance (k m) and gain (k g) were 0.66±0.02 and 0.42±0.04, respectively. This review indicated also that information is scarce for adult ewes at different physiological stages (maintenance, lactation, or pregnancy). More work is required regarding estimates of nutrient requirements of hair sheep in order to develop adjustments to existing nutrition models to predict animal's response under the conditions prevailing in the tropics (animal type, environment and feedstuffs available).

Dorper × Santa Ines F1 crossbred lambs under different grazing times and supplement levels in tropical regions: performance and macromineral requirements

“…The concentrations of Na and K in Dorper  Santa Ines F1 crossbred lambs found in this study are similar to those reported by the NRC (2007). The decrease in K is mainly due to higher accumulation of fat and reduction in muscle tissue (Pereira et al 2014;Pereira et al 2016). The estimated macromineral concentrations in this study are less than those recommended by the ARC (1980), which are fixed gain compositions of 0.41 g Mg/kg EBW, 1.8 g K/kg EBW and 1.1 g Na/kg EBW, respectively.…”

“…Mineral requirements in animals can be influenced by inherent characteristics of the feed or diet, such as organic or inorganic mineral fractions and element availability and chemical form in ingredients, as well as inherent factors of the animal, such as rate of production and previous nutrition, as well as factors related to antagonistic and agonistic interactions among minerals (Pereira et al 2016). Among the minerals, approximately 99% of calcium and 80% of phosphorus are found in bones, and the net requirements for gain are highly related to skeletal growth.…”

“…These two minerals promote animal growth, as observed in the estimation of body composition and gain (Table 5). One of the factors that affects body mineral composition is the proportion of minerals in fat, that is, when the deposition of fat increases, the proportion of minerals decreases (Ara ujo et al 2010;Pereira et al 2016).…”

“…There is a general paucity of literature concerning the nutritional requirements of crossbred hair sheep, and in Brazil, few studies on this subject have been conducted (Costa et al 2013;Regadas Filho et al 2013;Zhang et al 2015;Pereira et al 2016), and most describe protein and energy requirements . All animal tissues and feeds have varying quantities and proportions of mineral elements (Pereira et al 2016).…”

“…All animal tissues and feeds have varying quantities and proportions of mineral elements (Pereira et al 2016). Although the majority of natural mineral elements can be found in animal tissues, several of these minerals are purely derived from the diet and serve no essential functions in animal metabolism (McDonald et al 2010).…”