Poor weight gains a geniune beefJuly 23, 2014
Many Tasmanian beef producers have reported that animals appear to underperform during the summer/autumn period, and this is supported by data from on-farm trials at two locations in Tasmania. U
nderperformance is expressed primarily through cattle not putting on the expected live weight given the apparent quality and quantity of feed on offer. Autumn ill-thrift is a phenomenon recognised globally in temperate regions as affecting liveweight gains of both cattle and sheep. Whilst to some extent the causes of ill-thrift are multifactorial and can be difficult to determine, three key factors have been identified as being clearly linked with ill-thrift: 1. mycotoxins (produced by endophytes in pasture and cereal species); 2. pasture quality; and 3. parasites. The Tasmanian beef industry is dominated by perennial ryegrass pastures (80% of pastures are ryegrass) and very little use is made of fodder crops.
There is high prevalence of ryegrass staggers (64%) and of photosensitation (47%) reported by Tasmanian producers – these conditions are symptoms of mycotoxins. It is likely that subclinical effects of mycotoxins (underperformance) are even more prevalent than reported. Ryegrass pastures are also known to be poor quality in autumn, which is supported by the fact that improvements in grazing/feed management do assist with managing ill-thrift. Further work to understand fully the extent of mycotoxins and the effects they are having on Tasmanian beef production is recommended.