Tropical and subtropical grasses make up the majority of pasture species in northern grazing areas with subtropical species increasingly being introduced to southern grazing systems due to their high productive potential.
While such grasses grow rapidly in the right environment and can supply a vast amount of dry matter, goat producers need to be careful that the nutritional requirements of their goats are being met.
The levels of metabolisable protein and energy contained within such grasses can be low when compared to other temperate pastures and at peak times, such as during pregnancy and lactation, goats may not be able to consume enough of these grasses to meet their nutritional requirements.
While supplementation is one solution, a potentially more cost effective and long term strategy is to lift the feed value of the pasture through the introduction of tropical browse legumes. They can not only help meet the immediate requirements of high demand pregnant and lactating does, but can also result in increased turn-off rates and heavier weight-for-age carcases.
The costs and benefits of this strategy are the focus of a project currently being undertaken by the Meat Goat Research Program at James Cook University (JCU) in Townsville. The project is examining the role which three legumes – desmanthus, gliricidia and leucaena – may play in improving goatmeat production in sub-tropical and tropical Australia.
The results of this project will help goat producers predict the productivity gains associated with the inclusion of legumes in a pasture mix for breeding does and their progeny.
The choice of tropical legumes reflects their suitability for use in northern Australia. The legumes chosen for use in the trial have been selected based on their adaptability and ability to thrive in northern goat producing regions.
Cultivars of desmanthus are particularly well suited for pasture improvement across the cracking clay soils of Australia’s semi-arid rangelands from around Cobar in NSW through to central western and northern Queensland and across into the Northern Territory.
Gliricidia and leucaena are already well utilised in production systems with higher rainfall.
While the research is focussing on these three legume species, the results will be applicable to a range of tropical legumes available to livestock producers grazing sheep or goats across northern Australia.
The project team includes Dr Glen Walker, A/Prof Tony Parker, Mr Christopher Gardener, Prof Lee Fitzpatrick from JCU, Alice Wingfield from Cardiff University and Daniel Nogueira, visiting researcher from EMBRAPA (Brazilian Agricultural Research Corporation).