Early season nutritional disorders causing livestock deaths

District vets from the Hume Livestock Health and Pest Authority are seeing a rapidly increasing number of early season metabolic disorders in local sheep and cattle.

Steve Whittaker, Hume LHPA senior district vet, says this season is shaping up as one of the worst in years for pregnancy toxaemia (lambing sickness) and calcium deficiency in ewes. Deaths from grass tetany and calcium deficiency in cattle have also been confirmed.

"These problems are occurring much earlier in the season than we would normally expect, and we’re already seeing significant mortality rates in some affected flocks and herds," Mr Whittaker said.

"Unusual seasonal conditions have been a significant factor in causing these problems. Most stock have been running on green and plentiful pastures that are often deceptive in their nutritional value – low in energy, fibre and essential minerals such as calcium and magnesium.

"Ironically most of these cases are occurring in fat pregnant ewes and cows that are in excellent body condition with young calves at foot.

"Heavily pregnant ewes (and particularly those with twins) are often unable to ingest sufficient lush green feed to maintain their energy needs and the symptoms of pregnancy toxaemia set in – lethargy, separating off from the mob, not eating and inevitably death without very early treatment.
 
"Problems with pregnancy toxaemia have also been compounded by severe foot abscess and lameness this year which has affected the ability of ewes to get around and graze.

"On the other hand, lactating ewes and cows also have a very high demand for calcium and magnesium and these minerals are invariably low in the fresh, grass dominant pastures that we have at present. Hence there is a need for roughage and mineral supplementation in their diet.

"Stress factors such as the movement and yarding of ‘at risk’ stock, whose energy and mineral levels are already in a marginal state, are also triggering off a number of these nutritional disorders.

"Late shearing of ewes close to lambing, due to wet weather having delayed shearing schedules, has been a particular problem."

Strategies to prevent nutritional disorders include:

• feeding grain to late pregnant ewes;
• providing some high quality roughage;
• providing calcium and magnesium supplements to high risk classes of stock; and
• minimising movement of ‘at risk’ stock.

For more information on management of nutritional disorders contact your local LHPA district vet or livestock officer.

Media contact: Kylie Dunn 6391 3720 / 0428 465 378