Report lamb deaths and profit

Project leader John Ryan

At a glance

• Report deaths early to prevent further losses.
• Leading causes of lamb deaths in 2009–2010 were starvation and mismothering.
• Barber's Pole worm is rife this season.
• New lamb/kid death reporting system to be developed.

Farmers are being urged to report lamb and kid deaths as soon as they occur to prevent further stock losses and aid new research into the causes of mortality.

DPI project leader of the Lamb and Kid Mortality Surveillance Project, Dr John Ryan, said notifying the department and/or local vets of deaths as soon as they happened enabled all farmers to find out the causes.

Dr Ryan said diagnosing the cause of death early made the data from the project more reliable. Early in the project, he said many of the cases DPI were called out to had been dead too long for the cause of death to be accurately determined.

"You can put a tentative diagnosis, but you're really making an educated guess and not getting a proper diagnosis," he said.

"These have decreased in number. As the project has progressed and as we've educated farmers in what DPI are doing and the need for quick reports, we've improved the reliability and accuracy of the diagnosis.

"The main point about any disease investigation is if you can work out the factors that are causing it, the majority of the time you can change these factors.

"Changing one management or food-related factor may be all that's needed in the short-term. You stop the disease then work out how to prevent it in the future."

Dr Ryan said it also enabled DPI to detect early any new or emerging infectious or exotic diseases that could otherwise cause significant problems down the track.

"We go out to the farm, come up with a diagnosis and make recommendations on what the producer can do," Dr Ryan said.

Different years, different diseases

Dr Ryan said the vastly different climatic conditions experienced over the past two years had produced two diverse sets of data.

"If you look at the first year, internal parasites were not a big problem. This year, with the wet conditions over last summer, Barber's Pole worm has been rife," he said.

"Every second lamb case you were looking at had Barber's Pole worm infections.

"The moist and humid conditions had also led to high numbers of joint and gut infections."

Dr Ryan said navel ill infections — caused by bacteria entering through the umbilical cord and iodine deficiencies — were also on the rise this year.

"This year we had 7–8 cases of iodine deficiencies, ranging from one or two affected on a property to 75 on another.

"Last year, we didn't get anywhere near that."

In the project's first year, Dr Ryan said most lamb deaths related to nutritional issues, but diseases such as pulpy kidney continued to occur. In the second year worms, weeds and flies have been some of the leading causes of death.

What does the data reveal?

The project's report for 2009–2010 revealed that DPI and participating private veterinarians investigated 197 incidents and performed autopsies on 1443 lambs and kids. Almost half of the diseases identified were infectious, while another quarter of deaths related to poor nutrition (see Figure 1).

Figure 1: Proportion of diseases diagnosed by disease category

The cause of death was largely identified through laboratory results and autopsies, with winter identified as the worst time for lamb and kid deaths (see Figures 2 and 3).

Figure 2: Basis of disease diagnosis by disease category

Figure 3: Diagnosis of disease according to disease category and according to season

The primary cause of death was starvation and mismothering, which Dr Ryan said was not restricted to perinatal deaths and also involved older lambs following ewe deaths or mastitis. The next most common causes (see Table 1) were navel ill (omphalitis), internal parasites (helminths), trauma and enterotoxaemia (pulpy kidney).

For goats there were 34 clinically affected kids involved and 14 deaths from a total at risk population of 512. Similarly, for sheep there were 358 clinically affected lambs involved and 510 lamb deaths from a total at risk population of 8424.

The locations of the investigations are shown in Figure 4.

Figure 4: Investigations carried out throughout Victoria in comparison to the density of sheep populations in the state (the darker colours represent denser sheep populations)

Internal parasites accounted for about half the sheep deaths investigated (see Figure 5). Helminths — internal parasites — were found predominately in north-central and north-eastern Victoria.

Figure 5: Proportion of diseases diagnosed by disease

Next steps

Dr Ryan said the project team now planned to develop a reporting system about lamb and kid mortality for farmers that would notify them as particular diseases and conditions developed and provide targeted advice on how best to respond.

Although he stressed the need for farmers to get a professional diagnosis on lamb and kid deaths, Dr Ryan said there were certain precautions that they could take to improve survival rates.

"Look at pastures that are sheltered and out of the wind, so that when the lambs and kids are sheltering, they're warmer and drier.

Dr Ryan said ewes should be vaccinated coming up to lambing to increase maternal antibodies. Farmers should also ensure the ewes have ample feed available because this would keep them close to where they lamb or kid.

"Research shows the further ewes have to move away from the lamb or kid the more likely they are to forget where they left it."