title: Performance, nitrogen balance and microbial efficiency of beef cattle under concentrate supplementation strategies in intensive management of a tropical pasture.
abstract: The objective of this study was to evaluate the effect of concentrate supplementation strategies on the nutritional characteristics of beef cattle in intensive management of tropical pasture. Twenty-four Nellore steer at 250 kg body weight (BW) were used, divided into two plots, with 12 animals in each plot. The experimental area consisted of 32 paddocks with 0.25 ha of Panicum maximum cv. Mombaça. The experiment consisted of 96-day experimental periods, with three periods of 32 days. The strategies studied were P = exclusively on pasture and without concentrate supplementation (control), ES = pasture and supplemented with a concentrate low in protein, PS = pasture and supplemented with high protein content, and PES = pasture and supplementation with balanced protein-energy. There was reduced intake of DM in animals of the treatment P in relation to supplemented pasture, regardless of supplementation. Animals fed on ES showed an intake of more nutrients than the animals on PS. The CP and TDN were also lower in P than in pastures where animals received the additional types of concentrate, and the PS animals showed greater digestibility of CP and TDN than the ES animals. However, the animals exhibited similar weight gains. Animals on P ingested smaller amounts of N and had lower fecal excretion compared to the supplemented animals, but there was no difference between treatments in nitrogen balance. Urea nitrogen and urea from the blood were higher in the supplemented animals than in animals fed on pasture; these levels were also higher in PS animals compared to animals receiving ES. Both the purines absorbed and microbial protein production were similar between treatments. However, the animals fed with concentrate supplementation, independent of the strategy involved, showed higher microbial efficiency compared to animals fed exclusively on pasture.
authors.affiliation: School of Veterinary Medicine and Animal Science, Federal University of Bahia, Salvador, Bahia State, Brazil. tiagoticuro@yahoo.com.br.
authors.forename: Tiago Cunha
authors.initials: TC
authors.lastname: Rocha
authors.affiliation: Department of Animal Science, State University of North Fluminense Darcy Ribeiro, Campos dos Goytacazes City, Rio de Janeiro State, Brazil.
authors.forename: Carlos Augusto de Alencar
authors.initials: CA
authors.lastname: Fontes
authors.affiliation: Department of Animal Science, State University of North Fluminense Darcy Ribeiro, Campos dos Goytacazes City, Rio de Janeiro State, Brazil.
authors.forename: Renata Tavares Soares
authors.initials: RT
authors.lastname: da Silva
authors.affiliation: Department of Animal Science, State University of North Fluminense Darcy Ribeiro, Campos dos Goytacazes City, Rio de Janeiro State, Brazil.
authors.forename: Elizabeth Fonsêca
authors.initials: EF
authors.lastname: Processi
authors.affiliation: Department of Animal Science, State University of North Fluminense Darcy Ribeiro, Campos dos Goytacazes City, Rio de Janeiro State, Brazil.
authors.forename: Felipe Roberto Amaral Ferreira
authors.initials: FR
authors.lastname: do Valle
authors.affiliation: Department of Animal Science, State University of North Fluminense Darcy Ribeiro, Campos dos Goytacazes City, Rio de Janeiro State, Brazil.
authors.forename: Cláudio Teixeira
authors.initials: CT
authors.lastname: Lombardi
authors.affiliation: School of Veterinary Medicine and Animal Science, Federal University of Bahia, Salvador, Bahia State, Brazil.
authors.forename: Ronaldo Lopes
authors.initials: RL
authors.lastname: Oliveira
authors.affiliation: School of Veterinary Medicine and Animal Science, Federal University of Bahia, Salvador, Bahia State, Brazil.|Department of Animal Science, Federal University of Piauí, BR 135, Km 03, Bairro Planalto Horizonte, Bom Jesus, Piauí State, Brazil.
authors.forename: Leilson Rocha
authors.initials: LR
authors.lastname: Bezerra
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000822:Animal Husbandry; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001806:Blood Urea Nitrogen; D002417:Cattle / Q000502:physiology*; D004044:Dietary Proteins / Q000378:metabolism; D019587:Dietary Supplements; D002149:Energy Intake; D009584:Nitrogen / Q000378:metabolism; D000069466:Red Meat; D014329:Tropical Climate; D015430:Weight Gain
chemical_list: D004044:Dietary Proteins; D009584:Nitrogen
keywords: Cassava root; Digestibility; Feed supplementation; Intake; Panicum maximum