Energy and protein requirements of crossbred cattle in feedlot

Abstract

The objective of this study is to predict the energy and protein requirements of crossbred dairy cattle in feedlot. The study was conducted at the Unidade Acadêmica de Serra Talhada, Universidade Federal Rural de Pernambuco, Brazil with 30 bulls with a body weight of 339.1 ± 35.4 kg. Five animals were slaughtered at the end of the adaptation period to serve as the reference group; the remainder of the animals was slaughtered after 112 days. The latter group was randomly allocated to receive five treatments: 0, 17, 34, 51 and 68% of concentrate in the feed using a completely randomized design. The dietary intake of the animals that were not given concentrate was restricted to 1.5% of their body weight; these animals composed the group fed for maintenance. The body composition and empty body weight (EBW) were estimated by means of the comparative slaughter method and full dissection of a half-carcass. The results showed that for crossbred dairy bulls in confinement, the net and metabolizable energy requirements were 86.49 and 138 kcal EBW -0.75 day -1 , respectively, and the efficiency of use of metabolizable energy for maintenance and gain were 62.67% and 31.67%, respectively. The net energy (NE g ) and net protein (NP g ) requirements for gain can be estimated using the following equations, respectively: NE g = 0.0392*EBW e PLg = 242,34 × GPCVZ -23,09 × ER, respectivamente. A eficiência do uso da proteína metabolizável para ganho foi de 25,8% enquanto que as exigências de proteína para mantença foram 2,96 g PCVZ -0,75 dia -1 . A proteína degradável no rúmen pode suprir 62,44% das exigências em proteína bruta de bovinos mestiços leiteiros, machos não castrados, em confinamento, com peso corporal de 450 kg e ganho de 1 kg dia -1 . Palavras-chave: Composição corporal. Ganho de peso. Mantença.

<b>Cuts of dairy-origin cattle fed mesquite pod meal in replacement of corn

“…This assertion can be corroborated with results found by Neves et al (2016), who reported similarity in the nutritional requirements of dairy-origin male bovines when compared to Nelore and its crossbreeds. This means that dairy-origin bovines (Holstein-Zebu) present organs + viscera weight, carcass characteristics and cut weights similar to those of Nelore and its crossbreeds, which directly reflects on the parity of nutritional requirements.…”