Effect of storage period on the chemical composition and beta-carotene concentration in estilosantes hay varieties for feeding equine

Abstract

During dry seasons, equines are traditionally fed hay. However, if not prepared under favourable climatic conditions and if not well stored, hay does not preserve its nutritional value. The aim of this study was to evaluate the nutritional composition and beta-carotene concentration in Stylosanthes guianensis cv. Mineirão and Estilosantes Campo Grande hay varieties used to feed equines and assess the alterations that may occur during storage time. The leguminous plants were cultivated in a 1.5 ha plot and harvested after 127 days. The sun-dried products had humidity between 12 and 15% when transported into the storage shed. The samples were taken every 45 days over 225 days for analyses of dry matter (DM), mineral matter (MM), calcium (Ca), phosphorus (P), crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF), acid detergent insoluble nitrogen (ADIN), lignin, and beta-carotene. The treatments were Stylosanthes guianensis cv. Mineirão and Estilosantes Campo Grande hay varieties which were assessed at six moments of storage: 0, 45, 90, 135, 180, and 225 days. A completely randomized split-plot design was used. Once compared, there were differences (P<0.05) for DM, ADIN, ADF, and lignin. The storage period altered (P<0.05) the concentrations of DM, Ca, and CP in both varieties of hay. The concentrations of beta-carotene in the leguminous plants did not decline (P>0.05) throughout a period of 225 storage days. Storing hay, when well executed, maintains its levels of beta-carotene for at least 225 days, allowing for its use in equine feed, with no need for vitamin A supplementation. The nutritional composition suggested Estilosantes Campo Grande as the most appropriate hay to be used in equine diets.