A MEAT & Livestock Australia-funded on-farm study is investigating a little-known animal health issue - the cause of rib fractures in sheep.
PIRSA's Enhanced Abattoir Surveillance program undertaken at Thomas Foods International's Murray Bridge and Lobethal abattoirs has shown about 0.5 per cent of lambs processed have rib fractures.
The prevalence is closer to 1.5pc for lambs processed from the higher-rainfall Fleurieu Peninsula, Kangaroo Island and the Mid and Lower South East areas.
PIRSA Rural Solutions SA is working in collaboration with veterinarian and agricultural consultant Colin Trengove, who is undertaking his PhD on the issue which peaked at its highest levels in 2013.
Dr Trengove, who first came across rib fractures in lambs more than 30 years ago, said it would be good to get some answers for the industry to address the condition, believed to be a national issue.
"It can be costly in (carcase) weight loss with increased trim but one of the problems is that the loss is not quantified back to the producer," he said.
"The producer may get some feedback saying he has lambs with rib fractures but doesn't think much more about it.
"It is likely to slow growth rates as well as reduce animal welfare," he said.
PIRSA Rural Solutions SA principal livestock consultant Ian McFarland says processors would like to see the problem resolved, with considerable cost associated with slowing their chains to cut out any fractured ribs from carcases.
Literature around the world suggests a range of possible factors, from ewes trampling their lambs or rough handling during lamb marking, but Dr Trengove suggested that the fractures were trace element deficiency related and occurring at birth.
The fractured ribs invariably healed prior to slaughter so had occurred sometime earlier in the life of the lamb.
"We are finding it most on the acidic, duplex soils and is most likely caused by a complex interaction of elements including, copper, molybdenum and sulphur," he said.
More than 25 properties across SA have been involved in the on-farm preliminary study.
Soil and pasture samples along with bone and liver samples are being analysed for mineral levels and then correlated with the incidence of rib fractures.
Rib and long bone samples will also undergo density testing at the SA Health and Medical Research Institute for signs of osteoporosis - a sign of mineral imbalance.
