Supply levels of multiple supplements for beef heifers on pasture during the dry season: Intake and digestibility of nutrients

Abstract Text: This research aimed to evaluate the effect of levels of multiple supplements for beef heifers that were restricted grazing during the dry season on intake and digestibility of nutrients. Five Nellore heifers were used, with age and initial weights average of 20 months and 344.0 kg, respectively. The pastures were divided into five paddocks of 0.25 ha each, consisting of  Brachiaria brizantha cv. Marandu. The experiment was divided into 5 x 5 Latin square design, composed by five experimental periods of 20 days each and five animals. The strategy adopted was to provide multiple supplements (soybean hulls + ground corn grain + soybean meal + sunflower + urea and mineral mix) at levels of 2, 4, 6, and 8 kg/animal/day. The animals were fed in two fixed hours: 50% of the daily amount at 10 o'clock in the morning and 50% at 3 o'clock in the afternoon, the mineral mixture was offered ad libitum(control).To estimate feed intake, chromium oxide was used as an external marker and indigestible NDF was used as an internal marker.The faeces’ collection were made in 3 days in different collection times. The availability of total dry was 2.29 ton/ ha.  The intake dry matter, organic matter, crude protein (CP), non-fiber carbohydrates (NFC) and total digestible nutrients, and total apparent digestibility of dry matter, crude protein , total carbohydrates and NFC increased linearly (P<0.0001) and the dry matter intake of forage decreased (P<0.0001) with supplementation levels,it indicates that there was replacement effect. We conclude that providing supplement for grazing cattle in the dry season enhances the digestion of nutrients from forage.

Keywords: Brachiaria brizantha, replacement effect, nutrients intake