title: Nutritional Performance of Cattle Grazing during Rainy Season with Nitrogen and Starch Supplementation.
abstract: The objective of this work was to evaluate the effects of supplementation with nitrogen and starch on the nutritional performance of grazing cattle during the rainy season. Five rumen cannulated Nellore steers, averaging 211 kg of body weight (BW), were used. Animals grazed on five signal grass paddocks. Five treatments were evaluated: control (forage only), ruminal supplementation with nitrogen at 1 g of crude protein (CP)/kg BW, ruminal supplementation with starch at 2.5 g/kg BW, supplementation with nitrogen (1 g CP/kg BW) and starch (2.5 g/kg BW), and supplementation with nitrogen (1 g CP/kg BW) and a mixture of corn starch and nitrogenous compounds (2.5 g/kg BW), thereby resulting in an energy part of the supplement with 150 g CP/kg of dry matter (DM). This last treatment was considered an additional treatment. The experiment was carried out according to a 5 ×5 Latin square design following a 2×2+1 factorial arrangement (with or without nitrogen, with or without starch, and the additional treatment). Nitrogen supplementation did not affect (p>0.10) forage intake. Starch supplementation increased (p<0.10) total intake but did not affect (p<0.10) forage intake. There was an interaction between nitrogen and starch (p<0.10) for organic matter digestibility. Organic matter digestibility was increased only by supplying starch and nitrogen together. Nitrogen balance (NB) was increased (p<0.10) by the nitrogen supplementation as well as by starch supplementation. Despite this, even though a significant interaction was not observed (p>0.10), NB obtained with nitrogen plus starch supplementation was greater than NB obtained with either nitrogen or starch exclusive supplementation. Supplementation with starch and nitrogen to beef cattle grazing during the rainy season can possibly improve digestion and nitrogen retention in the animal..
authors.affiliation: Department of Animal Science, Universidade Federal de Viçosa, Viçosa, MG CEP 36570-000, Brazil.
authors.forename: Ísis
authors.initials: Í
authors.lastname: Lazzarini
authors.affiliation: Department of Animal Science, Universidade Federal de Viçosa, Viçosa, MG CEP 36570-000, Brazil.
authors.forename: Edenio
authors.initials: E
authors.lastname: Detmann
authors.affiliation: Department of Animal Science, Universidade Federal de Viçosa, Viçosa, MG CEP 36570-000, Brazil.
authors.forename: Sebastião
authors.initials: S
authors.lastname: de Campos Valadares Filho
authors.affiliation: Department of Animal Science, Universidade Federal de Viçosa, Viçosa, MG CEP 36570-000, Brazil.
authors.forename: Mário Fonseca
authors.initials: MF
authors.lastname: Paulino
authors.affiliation: Department of Animal Science, Universidade Federal de Viçosa, Viçosa, MG CEP 36570-000, Brazil.
authors.forename: Erick Darlisson
authors.initials: ED
authors.lastname: Batista
authors.affiliation: Department of Animal Science, Universidade Federal de Viçosa, Viçosa, MG CEP 36570-000, Brazil.
authors.forename: Luana Marta
authors.initials: LM
authors.lastname: de Almeida Rufino
authors.affiliation: Department of Animal Science, Universidade Federal de Viçosa, Viçosa, MG CEP 36570-000, Brazil.
authors.forename: William Lima Santiago
authors.initials: WL
authors.lastname: Dos Reis
authors.affiliation: Department of Animal Science, Universidade Federal de Viçosa, Viçosa, MG CEP 36570-000, Brazil.
authors.forename: Marcia
authors.initials: M
authors.lastname: de Oliveira Franco
keywords: Beef Cattle; Digestibility; Intake; Metabolism; Nellore Steers; Nitrogen Retention