Cattle make the most of dual-purpose crops

A Future Farmers Network webinar on the subject held by Charles Sturt University senior lecturer in agronomy Dr Jeff McCormick had 254 registrations last Thursday.

"People are interested because there's an opportunity, we've had a remarkable start to the season in many areas of the state, which means potentially we're growing a lot of feed," Dr McCormick said.

He said most farmers growing dual-purpose crops had sheep on their properties but he was suggesting there was the opportunity to introduce cattle on an agistment or trading basis.

"Commonly during winter the sheep on farm tend to be either pregnant ewes or ewes with very young lambs, so there is a limited supply of growing sheep to take advantage of dual-purpose crops," Dr McCormick said.

"In comparison, there are often large numbers of yearling cattle in southern Australia that are hand fed over winter achieving very little live-weight gain.

"The availability of large amounts of high quality forage through dual-purpose wheat and canola crops could transform a period of feed deficit for beef systems into a period of production."

Dr McCormick said his trials had shown cattle grazed on wheat with mineral supplements gained 2.5 kilograms a day.

While, cattle grazed on canola gained 1.75kg per day overall, weight gain improving the longer they were on the crop.

"In the first week that cattle were introduced to canola, some cattle put on 750 grams, other cattle didn't put on any weight," Dr McCormick said.

"After that their weight gain increased to just under 2kg per day for the next week, then it got to 2-2.5kg each day per head.

"Cattle need to be put on canola for at least four to five weeks to make up for that initial lag phase of their adaption."

He said there was little animal health risks when grazing cattle on wheat, but canola did pose issues.

"People are concerned about nitrate toxicity, PEM, related to high sulfur content, and also bloat, which I think is one of the largest risks," Dr McCormick said.

"Ideally cattle should have a short adaptation period where they are watched closely.

"Cattle grazing canola is not a system where you just leave them on and forget about them, that's when we can run into trouble."

Simon and James Finlay run a mixed-farming enterprise at Morven with their wives Sarah and Erin.

They predominantly run sheep but have been grazing cattle on dual-purpose crops for around 15 years.

"We introduced cattle mainly because in terms of biosecurity you can get cattle in easier for agistment and cattle are more likely to pay with backgrounding on a dollars per kilo, weight gain basis," Mr Finlay said.

He said the biggest animal health issue they had encountered grazing cattle on canola was bloat.

"We've found that bloat is very related to frost events," Mr Finlay said.

"If we get consecutive frosts, normally three in a row, they have a lot of trouble."

Mr Finlay explained a big frost could freeze the crop until lunchtime and as the cattle didn't like eating it when it was frozen they could go hungry.

"They'll start eating it that afternoon, but if you get another frost the next day the same thing happens, so each day they're emptying themselves out and by the time you get to the third day they gorge themselves," Mr Finlay said.

He said to combat this issue they fed them straw and even took them off the crop if they knew there was a cold week coming up.

"We put them into a paddock that's only 60 to 70 per cent arable with hills and gullies," Mr Finlay said.

"Or we have a refuge paddock next door and we swing the gates open and let them go in there."

However, minimal losses due to bloat were countered by the weight gains they saw with canola, cattle putting on between 1.3kg to 2kg per day.

He said they also tried to move their cattle between the different crops roughly every five weeks to ensure they retained around 1000kg of dry-matter per paddock.

"We get better recovery if we do that and also once you get over 3000 to 4000kg of dry matter you get some spoilage so you don't want to waste it," Mr Finlay said.

The Finlays either sell into the feedlots or over the hook.

"They'll go into clover paddocks at 380-400kg if we want to do another 100kg in the Spring flush to finish them," Mr Finlay said.