Risk to livestock emerging due to 'green drought'

01 Dec 2023

A sudden change of feed can result in pulpy kidney, a disease in cattle, sheep and goats caused by the overgrowth of clostridial organisms or bacteria in the gut due to the consumption of high carbohydrate feed. Animals being supplemented with heavy grain feeding or moving onto fresh green pasture are at high risk of the disease, which often manifests in young, fast growing livestock that are unweaned or recently weaned and are without a full vaccination history. Pulpy kidney is fast acting and there are often no prior signs of sickness in livestock.

Andrew Biddle, District Veterinarian, recommends a vaccination program of two doses of 5-in-1, dosed 4-6 weeks apart initially followed by a quarterly booster to achieve lasting protection against pulpy kidney.

“More frequent boosters are required in high-risk conditions like that we are currently experiencing, he said. “It is also important to provide pregnant or lactating livestock with a mineral lick as animals are more susceptible to metabolic diseases such as pregnancy toxaemia, grass tetany and milk fever during these conditions”, said Dr Biddle.

While ‘green pick’ is a great sign of pasture growth and a reduced reliance on supplementary feed, new green growth also has a water content of up to 90%, making it impossible for animals to eat enough to satisfy their nutritional needs if they do not also have access to other types of feed. It can take between 3 – 8 weeks before pastures offer a useful quantity of feed, with growth depending on the species of pasture and the height and density of these pastures before the rain event. Grazing pastures with a high water content (70-90% water) and short height (30-90mm) means livestock will expend more energy grazing for many hours, but can also set pasture recovery back significantly.

“Producers should continue to provide supplementary feed for livestock until pastures mature and the water content drops”, said Dr Biddle.

A good rule of thumb before grazing is that pastures should be at a starting point of 10cm height or over, providing at least 1200kg Green DM/Ha (Green Dry matter per Hectare). Livestock are best fed in smaller paddocks where they can’t chase green pick while those paddocks recover. Another strategy can be to slow down the paddock rotations, giving recovering pastures longer to grow while producers supplementary feed.

The Drought and Supplementary Feed Calculator can be a useful tool to assist in decision making around feeding livestock.

For more information about livestock health, contact your Local Land Services District Vet or Livestock Officer on 1300 795 299.