MARTHEN LUTHER MULLIK1, PUTRI EYANOER2, DENNIS POPPI3, STUARD MCLENNAN4
1University of Nusa Cendana, Department of Animal Nutrition, Indonesia
2North Sumatera University, Medicine, Indonesia
3The University of Queensland, Food and Land Sciencies, Australia
4Queensland Beef Research Institute, Australia
To achieve market standard weight at younger age requires a higher growth rate of grazing steers either in the wet and the dry season. The present experiment aimed at maximising wet season growth rates by providing extra energy and protein to steers grazing good quality tropical pasture during the wet season. Twenty-five Brahman crossbred steers (2034.2kg) were allocated to 5 treatments, namely control (Con; grazing only), Con + molasses/urea (3% urea) at an intake of 0.5% liveweight (W) (5MU) or 1.0% W (10MU), and Con + mixture of molasses/urea (55%), fish meal (25%) and whole cottonseed (WCS; 20%) at an intake of 0.5% W (5MWF) or 1.0% W (10MWF). All steers grazed fertilised Pangola grass pasture (Digitaria eriantha cv Steudal) for 84 d between January and April (wet season). Total dry matter (DM) for all paddocks was maintained at >1.9tha-1. Mean green leaf yield was 1.9tDMha-1. In vitro dry matter digestibility was 64% and crude protein content was 15%. Control steers gained weight at 960gd-1. Providing molasses/urea did not increase liveweight gain (LWG) but inclusion of fishmeal and whole cottonseed markedly increased (p < 0.05) daily LWG above control by 34% and 39% for 5MWF and 10MWF, respectively. There was no statistical difference in the LWG response between the levels of supplement feeding. It was concluded that provision of molasses/urea as rumen fermentable energy and protein alone will not increase LWG of steers grazing good quality Pangola grass pasture, but the inclusion of whole cottonseed and fishmeal will significantly increase LWG, most probably as a result of the higher bypass protein and energy intake from the MWF supplement.
Keywords: Energy bypass protein, grazing, Pangola grass pasture, steers, tropical pasture