MLA and ASHEEP project trials early weaning in cattle

As such, a common perception may be the bigger the calf at weaning, the bigger the pay cheque.

However, Swans Veterinary Services partner Enoch Bergman said this was an assumption which may require more consideration.

And a new producer demonstration site (PDS) project, run in conjunction with Esperance grower group ASHEEP, Swans Veterinary Services and Meat & Livestock Australia (MLA), is looking into exactly that by highlighting the benefits of weaning two months earlier than typical for the district.

As part of the three-year project, eight South West cattle producers agreed to break away from the tradition with half of their herd.

Those involved nominated exactly when they wanted to wean, with Dr Bergman weighing all cows and calves two months before the proposed date, before cows were wet/dried and their body condition score estimated.

He excluded any dry cows from the PDS and managed the weaned calves separately.

"Calves remaining on their dams will be weaned about two months later," Dr Bergman said.

"Everything will be weighed again and the cow's body condition scored.

"Again, they will be wet/dried to ascertain which ones are more likely to have had their calf weaned previously.

"The body condition score and weights of the wet versus dry cows will be compared, excluding the cows that were dry at the first round of weaning."

So what exactly is the PDS trying to demonstrate?

Dr Bergman hopes to show there is "very little difference" between calves weaned earlier and later.

However, he said there should be a measurable difference in the weight and body condition scores of the cows.

The Esperance veterinarian said while cows used considerable amounts of energy to produce milk, only about 40 per cent of that energy was transferred to the calf once they grew too old to adequately digest milk.

Unfortunately, he said there was no way around the significant energy input, as milk is simply an expensive product for a cow's liver to produce.

"Once it is created, we should endeavour to ensure none of that precious resource is wasted," Dr Bergman said.

"Mother Nature has helped in that endeavour, as 90pc of the energy from milk is absorbed by a newborn calf - until the calf becomes a ruminant.

"Once a calf weighs over about 150 kilograms, their rumen develops and they lose some of their ability to digest milk.

"If left on their mothers they would continue to hit the milk bar as long as we, and their mother, would let them."

To put it into perspective, Dr Bergman said calculations showed that a cow with a calf at food needed 15.5 kilograms of dry matter to maintain their own body weight and feed their calf.

If the pair was separated, and left to fend for themselves, only 9.6kgs of dry matter would be needed to maintain the cow and grow her weaned calf to the same extent.

In a nutshell, he said producers could budget on reducing their animal's feed requirements by as much as 38pc once calves had been weaned.

"By getting calves off their mothers a bit earlier, and before the season finishes, better feed resources can be partitioned to go down the throats of calves," he said.

"This is while simultaneously allowing producers to protect the body condition of their breeding females with far less resources, having dropped the dam's dry matter requirements from 15.5kg to a mere 6kg.

"No wonder cows, which fail to raise a calf, struggle to fit through the crush."

Separately, Dr Bergman said weaning calves earlier would also reduce morbidity and mortality rates in the feedlot.

He said one of his lot feeding clients had shown an eight-fold increase in morbidity and seven-fold increase in mortality for calves that had transitioned through the saleyards, when compared to those that had been weaned in the yard and brought through vendors.

"It is madness," Dr Bergman said.

"While some producers which adapt to early weaning may exit them shortly after they wean, a large number are going to carry them through and either grass finish or background them for a little while longer before selling them.

"We believe the rumen in those animals, which have been eating strictly grass and no milk, changes to optimise the ability to extract as much energy as possible from the forages they eat in the form of highly energetic short chain volatile fatty acids.

"However, when there is still milk in the mix the rumen doesn't develop as much surface area to help effectively absorb those volatile fatty acids."

Dr Bergman hopes earlier weaned calves may even be heavier at the end mark, when they are sent to market as a backgrounded or grassfed calf due to their rumens being further developed and better adapted to grass, compared to their siblings who were weaned later.

Additionally, he said if producers start consistently weaning earlier, they could protect their cows' body condition meaning they should be able to conceivably run more cows on the same feed resource.

"We could arguably even reduce our carbon footprint as well, because it is all about how much cellulose goes into the mouth of an animal compared to how much meat goes onto the hook," Dr Bergman said.

"Anything that improves kilograms of beef per hectare also improves our carbon story, which is actually pretty awesome already.

"What our detractors fail to seem to recognise is that if animals don't eat grass, most of that carbon will end up in the atmosphere regardless, whether that be carbon dioxide or methane depending on how it degrades, so putting it through a cow doesn't really change anything - we are inherently carbon neutral."

He added, "the methane our animals produced 12 years ago has degraded, offsetting the methane we produce today.

"We are not the problem, sequestered carbon released into the atmosphere is the driver of climate change, not ruminants," Dr Bergman said.

"But, if we improve our efficiencies, we can still help the rest of the world in the process."