ABSTRACT The objective of this study was to evaluate the production performance and carcass traits of feedlot steers fed a high-energy diet supplemented with doses of an enzyme complex (0, 2.5, 5.0, and, 7.5 g animal−1 day−1). Thirty-two ½ Angus ½ Nellore crossbred steers at an average age of 12 months and an average initial weight of 422 kg, were kept in a feedlot for 77 days. The roughage-free diet was composed of a mixture of whole corn grain and a protein-mineral-vitamin mix at a constant ratio of 85:15, on a dry matter basis. A completely randomized block design was adopted, consisting of four treatments and four replicates, in which each replicate was represented by a stall with two animals. Each gram of product added to the diet led to a decrease of 0.0818 kg in daily dry matter intake (DMI), whereas fat thickness at the ribs and at the hindquarter increased by 0.3850 and 0.080 mm, respectively. Feed efficiency increased by 0.0054 kg BW kg DMI−1 per gram of enzyme added. Apparent dry matter digestibility had a quadratic response, with maximum digestion manifested at the dose of 4.78 g animal−1 day−1. The gradual inclusion of enzyme complex reduces the DMI but increases feed efficiency and carcass fat cover of feedlot steers.

O objetivo deste trabalho foi avaliar o desempenho de bezerros holandeses nas fases de aleitamento e pós-desmame, manejados intensivamente na fase de aleitamento com ausência ou presença de feno. Foram utilizados 24 bezerros holandeses machos, com média de idade de 15 dias e peso inicial 43 kg. O delineamento estatístico foi o inteiramente casualizado, constituído de dois tratamentos e seis repetições. Os tratamentos foram: 1) aleitamento com substituto lácteo + concentrado inicial para bezerros, ad libitum + feno de gramínea temperada (aveia e azevém), ad libitum; 2) aleitamento com substituto lácteo + concentrado inicial para bezerros, ad libitum. Não houve diferença significativa entre os tratamentos para ganho de peso e conversão alimentar. Entretanto, o fornecimento de feno causou aumento do consumo diário de matéria seca (2,127 vs 1,894 kg). A ingestão de feno promoveu maior estímulo ao consumo de concentrado e maior peso ao desmame.

The objective of this work was to evaluate the performance of Holstein calves in suckling and post-weaning phases, intensively managed during suckling in the absence or presence of hay. Twenty-four male Holstein calves, at an average age of 15 days and initial weight of 43 kg were used in the experiment. The experimental design was completely randomized, consisting of two treatments and six replications. The treatments were as follows: 1) suckling with milk substitute + initial concentrate for calves, ad libitum + temperate grass hay (oat/ryegrass), ad libitum; 2) suckling with milk substitute + initial concentrate for calves, ad libitum. No significant difference was found between treatments for weight gain and feed conversion. However, the supply of hay caused an increase in daily dry matter intake (2.127 vs 1.894 kg). The intake of hay promoted greater stimulus to consumption of concentrate and greater weight at weaning.