Not a lot of work had been done to figure out why sheep go lame, but some Alberta researchers are working to change this.
“We would like to develop a strategy to diagnose lame sheep which can later be used to inform best management practices to treat these animals,” said Wiolene Montanari Nordi, at the recent AGM of the Alberta Lamb Producers.
Montanari Nordi, a post-doctoral fellow from Brazil, is working with Karen Schwartzkopf-Genswein’s research group at Agriculture and Agri-Food Canada’s Lethbridge research centre. Their work, focused on lameness in feedlot lambs and ewe flocks, involves assessing lambs and ewes and then following up with post-mortems after slaughter. (The group is about halfway through the study but is still looking for producers with ewe flocks who would like to participate.)
When lame animals are found, they are scored as mildly, moderately, or severely lame. The researchers then document risk factors for lameness, including what breed and sex; how muddy the pens are; how long the animal has been on feed; and whether it has been previously lame and what treatment was given. Pen density, bunk space, diet, weather, and environmental factors are also considered. Foot rot and digital dermatitis are the focus, with infrared photos taken to assess inflammation.
“We bring this information together collected with risk factors,” said Montanari Nordi. “We use all this information to help us understand how lameness develops.”
During feedlot assessments, the scientists have been seeing many cases of lameness, brought on by injuries, she said. In some cases, animals have broken legs.
“We have been seeing cases of joint infection,” added Montanari Nordi.
Other problems include broken hooves, club feet, overgrown hooves, and laminitis. Poor conformation in the legs and hoof is a major cause of lameness, and others are infection driven, such as digital dermatitis or foot rot that are caused by specific bacteria.
In digital dermatitis, the infection is concentrated between the toe, when mud has accumulated in the pen. In foot rot, the bacteria overruns both the hoof and the sole.
“When we have five per cent of the animals with foot rot or digital dermatitis in a pen, we call it an outbreak,” she said.