Block of mineral salt in the diet of sheep and lambs and their effects on health and performance

Abstract

Sheep farming is growing worldwide (FAOSTAT, 2016), including in tropical areas, where production of dry forage is high; however, it has a lower content of nutrients in comparison with forage of temperate climates. Overcoming nutritional deficiency of animals fed tropical forages is a challenge, especially during dry seasons. The grazing method is used to maximize forage production and reduce feeding costs. However, due to the high nutritional needs of lambs in the growing stage, they can be stall-fed at finishing, as they are slaughtered young and have a greater nutritional need than ewes do. Supplements to grazing sheep are used to enhance animal performance, as well as to improve animal health (PEREIRA et al., 2017). Supplementation with minerals is critical to animal performance and health due to mineral deficiencies in the soil-plant system, which directly affect animal nutrition. Mineral deficiency negatively influences animal growth, reproduction, immune system, cellular replication, skeletal progress, and energetic metabolism (WANG et al., 2009; HAENLEIN; ANKE, 2011; OVERTON; YASUI, 2014). The mineral supplementation is traditionally offered as powder, which limits its adequate use due to its hygroscopic characteristics. Multi-nutritional block is an alternative for mineral supplementation for sheep production systems. The use of minerals in block influence positively parameters, such as feeding efficiency, milk production, reproductive performance (KIOUMARSI et al., 2011; WANG et al., 2016). The use of mineral blocks is easy and efficient, and sheep can receive the necessary requirements of oligoelements to ensure health and optimum productivity, with reports of various benefits for reproduction, reduction of mortality rate, greater economic return (WANG et al., 2016). We hypothesized if sheep and lambs have good intake of mineral salt in block and if its consumption is beneficial to their health, performance and skeletal quality. The objective of this study was to assess the effects of mineral supplementation in a block format salt on the consumption, performance, skeletal characteristics and hematological and biochemical parameters of sheep and lambs reared under tropical conditions. MATERIAL AND METHODS The experiment protocol for the present experiment was approved by the Animal Ethics and Well-being Committee of the University of São Paulo, No. 8755210515, issued on July 7, 2015. The study was divided into two experiments. The first experiment comprised pregnant sheep reared under the grazing system and the second with stall-finished lambs. Both were conducted in the Faculty of Animal Science and Food Engineering of the