THE use of hormone growth promotants is no longer acceptable for many beef cattle markets, resulting in graziers being on the lookout for something that will give similar improvements in animal growth rates.

In this year’s Gympie Carcass Classic feedlot ration a yeast-based product has been used with some success.
Animal nutritionist Natalie Temple explained how the animal rumen process works and how it can be improved.

“The rumen is host to an incredible number of different organisms, all having a specific task in enabling the digestion of high cellulose food,” she said.

“A specially selected yeast product, known as levucell, can positively moderate rumen conditions.”

She said in high energy diets the risk of developing acidisosis with potentially fatal results could be high.

“The faster a feed passes through the rumen, the greater the risk of there being acid build up problems,” Ms Temple said.

“Grains such as wheat, pass through relatively rapidly and the increase in acidity reduces the number and type of bugs in the rumen.”

Ms Temple said if the rumen bugs changed, an animal might suffer gastric upsets and have a greatly reduced feed intake with resultant weight loss.

“If animals are on poor quality high fibre rations, such as some hay or silage, the use of the yeast supplement can improve use,” she said.

“The supplement is also helpful in getting more out of the grain content in corn silage.”

Ms Temple said sub-acute acidosis did not display symptoms but could reduce growth rates by as much as 25% and lower.

“The sub-acute form can be hard to diagnose but should be considered as a possible if the above conditions are prevalent in your herd,” she said.

In a dairy herd 0.5g of supplement a day costs about 8.5 cents and can give a litre of milk a day extra production per cow.

In beef herds a convenient method of delivery is in the process of being developed but trials have shown weight gain and the ability for calves to go onto hand feeding, for exaple for strategic early weaning, more efficiently.