Feeding behavior of Nellore heifers grazing during the dry season of the year supplemented with mineral salt and urea types

• Main Authors: Aléx Schio Resende, Fabiano Ferreira da Silva, Evely Giovanna Leite Costa, Robério Rodrigues Silva, Dicastro Dias de Souza, Antonio Ferraz Porto Junior, Bismarck Moreira Santiago, Eli Santana de Oliveira Rodrigues, Edvaldo Nascimento Costa, Jemima Fialho Muricy
• Format: Article
• Language: English
• Published: Universidade Estadual de Londrina 2018-08-01
• Series: Semina: Ciências Agrárias
• Subjects: Consumo; Diferimento; Nitrogênio não proteico; Ruminante.
• Online Access: http://www.uel.br/revistas/uel/index.php/semagrarias/article/view/31660
• ISSN: 1676-546X; 1679-0359

In this study, the feeding behavior of Nellore heifers receiving supplements containing mineral salt, conventional urea and slow release urea during the grazing stage at Brachiaria brizantha-based pastures during the dry period of the year was evaluated. Fifty-six heifers with approximately 284.72 ± 27.48 kg of body weight were used, distributed in a completely randomized design with four different treatment types: mineral salt; Urea - supplementation with 8.18% conventional urea; Mixed urea - supplementation with 4.09% conventional urea and 4.39% slow release urea and slow urea - supplementation with 8.78% slow release urea. Animals supplemented with mineral salt had longer grazing times compared to those supplemented with mixed urea, slow urea and regular urea. The dry matter intake, neutral detergent fiber and total digestible nutrients presented a similar effect, with higher values for heifers consuming supplements containing regular urea and slow urea compared to those of mixed urea. However, when the efficiency of hourly intake was evaluated, the animals that received urea supplement were more efficient in relation to the other treatments. The number of grazing periods for heifers receiving slow urea supplementation was higher compared to heifers receiving salt and mixed urea. The duration of grazing and rumination periods was longer for heifers receiving salt supplementation and mixed urea than those receiving regular urea and slow urea. It is recommended to use supplements at the level of 0.3% of body weight for heifers receiving conventional urea.