Levels of ground corn supplied to beef heifers at pasture during the rainy season: productive performance, intake, digestibility and microbial efficiency

Abstract

-The objective was to evaluate the effect of four levels of ground corn supply on nutritional parameters, microbial synthesis efficiency and growing performance of beef heifers, at the rainy season. For such, 28 crossbred yearling heifers, with initial age of 16-17 months and initial weight of 255 ± 31.0 kg were distributed into five paddoks of B. decumbens, of 2.0 ha each, with average potentially digestible DM availability of 2,377.0 kg/ha. For each one of the lots, one of the following supplements was daily supplied: mineral mix exclusively or with ground corn at levels 0.25, 0.50, 0.75 or 1.00 kg/day. The experiment was arranged in completely randomized design with five treatments (supplements), five repetitions for the groups receiving exclusive mineral mix or mineral mix plus corn on the level of 0.50 kg/day and six repetitions for those receiving the other supplements. There was a response of 0.092 kg of weight gain for every 1 kg of ground corn supplied to the animals, and no substitution effect was verified on the dry matter intake of pasture. The increase in ground corn levels increased metabolizable energy intake, which is explained by the crescent linear effect on digestible dry matter intake, on apparent digestibility of dry matter and organic matter as well as on the levels of total digestible nutrients of the diet consistent with the increase in intake of the most digestible ingredient, ground corn. In the same way, there was a positive linear effect for apparent digestibility of neutral detergent fiber. The supplementation provided linear positive effect on the flow of microbial nitrogen compounds (MICN) for the small intestine, and did not affect the microbial synthesis efficiency.The supply of energetic supplement for beef heifers, at pasture, during the rainy season increases the use of the forage and consequently, weight gain.

Nutritional Evaluation of Young Bulls on Tropical Pasture Receiving Supplements with Different Protein:Carbohydrate Ratios

“…Even though supplementation provided increases in DM digestibility during the rainy season, all nutritional plans had similar intakes of DM and TDN. Although some authors ( Nascimento et al, 2010 ; Figueiredo et al, 2011 ) observed increases in TDN intake without changes in DM intake due to the many factors that make treatment effects less visible over cattle on pasture condition, other authors ( Figueiredo et al, 2008 ; Barros et al, 2011 ) did find differences.…”

“…Energetic supplements usually increase the amount of total energy intake, mainly by directly supplying energy from supplements, since normally there is no increase in pasture intake ( Figueiredo et al, 2011 ). Thus, the energetic supplement (LPHC, 15% CP) provided lower fiber digestibility with similar TDN intake when compared to the other supplements.…”

Experiencias sobre la suplementación de rumiantes desarrolladas en la Universidad Federal do Río Grande do Sul, Brasil

“…Una de las herramientas nutricionales para optimizar el comportamiento productivo y reproductivo de novillas pastoreando, es la suplementación energética (Lobato, 2009) y el uso de aditivos como el antibiótico virginiamicina, que ha mostrado tener una eficiencia en el control de acidosis en bovinos alimentados intensivamente en corral, con raciones con grano por arriba de la mitad de ración, por lo tanto su utilización, puede promover un mayor rendimiento de ganado criado en pastos (Ferreira et al, 2011). En cuanto a los primeros, cabe destacar la importancia de la sustitución, ya que en general, la suplementación se basa en reemplazar parte de la energía aportada por los pastos disminuyendo el consumo de forraje por animal, a medida que se aumenta el porcentaje de participación del concentrado en la dieta (Figueiredo et al, 2011). El grano de maíz ha sido la materia prima usada por excelencia en Brasil para la fabricación de concentrados energéticos para la producción animal, y su uso se ha visto afectado debido a su diversificación en otros campos como al consumo humano, y uso para fabricación de biocombustibles.…”