Depending on feed levels, producers with autumn calving cows may be considering weaning calves earlier than normal.
Early weaning is an immediate way to reduce feed requirements on farm, according to Agriculture Victoria livestock development officer, Nick Linden.
“By separating the cow and calf there is a potential reduction in daily feed intake of up to 24 per cent,” Mr Linden said.
“As an example, a six month pregnant cow with a 250kg calf at foot will consume in the order of 15kg of feed per day (150 MJ of energy) – if we split the cow and calf into two individual units, the dry cow could maintain herself on about 6kg DM per day (64 MJ of energy), and the calf would be gaining 0.5kg per day consuming 5kg DM (50 MJ of energy) per day.”
He said the exact amount of feed required/saved depended on the quality of the feed on offer – but the principle remained the same.
“As soon as the calf is removed from the cow, she will partition energy back to her own requirements, enabling the higher quality feed to be prioritised to the calf.
“Weaned calves can then become the priority mob for feeding.
“If you have a limited supply of high-quality feed, it doesn’t have to be processed through the cow into milk for the calf to perform.
“It may be more efficient to offer it directly to the calves, without having to maintain the mature cow.
“Poorer quality pasture can then be offered to the dry cows – which can result in significant savings.”
Mr Linden said while cow condition was often a key determinant of whether to early wean, calf condition was also important to consider – calves with dry, coarse coats are most likely not receiving enough milk from their mothers and may be better off having direct access to higher quality feed.
“In most situations when early weaning you would aim to have calves at least 12 weeks of age or around 100kg live weight,” he said.
“However, if cow condition and survival is a significant risk, calves can be weaned as light as 80kg. If needing to wean calves at these lighter weights, it is recommended you seek specific advice from your veterinarian.”
If supplementing calves after weaning, he said it was good practice to expose the calves to the supplement prior to weaning.
“This not only helps educate the weaners to what they will be eating, but it also gives the rumen bacteria time to adjust to a change in diet.
“It’s worth remembering that weaners have specific requirements.
“The younger or lighter they are, the greater their protein requirement will be – as an indication, weaners are likely to need feed that is 16 per cent crude protein.
“Depending on the size of the weaners, the physical capacity of the rumen may also be an issue – so all feed needs to have a high concentration of energy.
“Feed for weaners will need to be at least 11 megajoules of energy per kg DM.
“If you don’t know how much protein or energy is in your feed – doing a feed test is the best way to be sure your animals are getting fed the nutrition they need.”
Mr Linden said to aim for a calf growth rate of at least 0.6kg/day until they are heavier than 250kg, which will also ensure later growth rates are not compromised.
Weaners are highly susceptible to internal parasites and the risk of parasites increases when cattle have been grazing short pastures.
While cattle growth rates give a good indication, a worm egg count taken 14 days after drenching is a useful way to assess the effectiveness of the drenching program.
Vaccination for clostridial diseases is also important for weaners.
“While early weaning is an option to reduce overall feed requirements and look after cow condition, it’s not for everyone,” Mr Linden said.
“It does require more intensive management and works best for producers that have a shorter more condensed calving period.”
If considering weaning calves earlier than normal, it’s well worth doing a feed budget/plan to ensure there are adequate feed and resources on hand.
“If you haven’t early weaned before, consider doing it with one mob initially,” he said. “Cow mobs under the most pressure may include the first calf heifers or the oldest cows – so either of these groups could be suitable candidates.
“Whether early weaning or weaning at the usual time, there are lots of things to consider – what are the feed and animal health requirements? How will I wean – cold turkey separation at either ends of the farm, in the yards or along a fence line?
“Weaning is a critical point to get right and set animals up for future productivity.”
