Interactions among monensin, soybean oil and nitrogen source on feedlot performance of Aberdeen Angus steers

Quarenta novilhos Aberdeen Angus foram usados para avaliar o efeito da monensina, óleo de soja e fontes de nitrogênio (farelo de soja ou uréia) sobre o desempenho de novilhos em dietas com 90% de concentrado. A monensina diminuiu o consumo de matéria seca em dietas contendo farelo de soja e o peso corporal aos 56 e 112 dias. O óleo diminuiu o ganho de peso nos períodos de 57-112 dias e 1-112 dias, enquanto a monensina diminuiu o ganho de peso nestes períodos nas dietas contendo farelo de soja como fonte de nitrogênio. O óleo de soja piorou a eficiência alimentar em todos os períodos e o farelo de soja, comparado com dietas com uréia, nos períodos de 57-112 dias e 1-112 dias. A monensina melhorou a eficiência alimentar em 7,4% para as dietas contendo farelo de soja, na ausência de óleo de soja, mas não alterou a eficiência alimentar para as dietas contendo uréia. Por outro lado, a monensina piorou a eficiência alimentar em 13% para as dietas contendo farelo de soja e óleo de soja.Fourty Aberdeen Angus steers were used to evaluate the effects of monensin, soybean oil and nitrogen source (soybean meal or urea) on feedlot performance of steers fed 90% concentrate diets. The monensin decreased dry matter intake of soybean meal supplemented diets and decreased the body weight at 56 and 112 days. The soybean oil decreased the average daily gain from days 57 to 112 and 1 to 112. While, monensin showed a decreased on the average daily gain in these periods in the diets containing soybean meal as nitrogen source. The soybean oil decreased feed efficiency on all periods and soybean meal, as compared to urea diets, in the days from 57 to 112 and 1 to 112 periods. The monensin increased feed efficiency in 7.4% for the diets containing soybean meal, without soybean oil, but it did not change the feed efficiency for diets containing urea. In contrast, monensin decreased feed efficiency in 13% for the diets containing soybean meal and soybean oil