Advice on step-down weaning for calves to avoid setbacks

Feeding high volumes of milk to calves during their most efficient and cost-effective growth phase needs a step-down protocol to ensure a smooth transition through weaning.

Without it, the two to four weeks post-weaning can be a series of setbacks: disease, scour, acidosis, or a reduction in daily liveweight gain.

All these issues counteract the benefit of feeding more milk to meet the calf’s biological needs.

See also: Advice on feeding calves for good rumen development

Planning weaning is, therefore, an important part of the rearing strategy, according to vet and youngstock consultant Kat Hart, of the George Veterinary Group in Malmesbury, Wiltshire.

She says weaning calves off high milk volumes is a challenge. “It should be possible to get the average group of calves to have a smooth transition, although there will always be outliers,” she adds.

Kat Hart © George Veterinary Group

Milk replacer feeding regimes from the 1970s were based around saving money, so advocated just two litres twice a day and weaning abruptly at six to seven weeks of age.

There was no understanding that calves could not physically digest enough concentrates at that stage of life.

“Now we better understand from research that it’s best for lifetime performance if we invest in giving the volume and quality of milk powder in those early weeks,” says Kat.

Peak milk intake

The downside of increasing milk volumes to high levels (8-10 litres-plus) or ad-lib is that it takes time to reach peak intake.

Litres must then be slowly reduced to ensure that calves are eating enough concentrates to replace their milk diet, as well as to avoid digestive upsets.

“When you suddenly stop feeding milk there is a stress impact on the calf.  Immunity is hit and you are likely to get disease.

Concentrate intakes won’t be high enough and without milk feed there is no nutrition going into the calf – its guts and microbiome are not yet ready for the post-weaning diet,” explains Kat.

As a result, weaning age must be dictated by how long the calf is at peak milk. Kat says this means a more “normal” weaning age of nine to 10 weeks.

“If you are ad-lib feeding at week four of age, then it takes five weeks to step down and wean. Dairy farms feeding eight litres a day should wean over a minimum of three weeks.

“And really high volumes of 10 litres-plus will need to extend to 12 weeks and will be feeding once a day for the last three weeks,” she explains.

This longer weaning phase means shed space also has to be reconsidered (because of the extra housing period) to allow sufficient time for rest and cleaning between batches of calves.

Kat advocates drawing up a written weaning protocol with the farm’s vet and youngstock staff, particularly for manual feeding systems, as “things can slide” if other jobs take priority.

Automated weaning

Farms that have installed automatic feeding systems mostly have an in-built weaning program, she says.

The computer gradually reduces the amount of milk fed each day, and while this is a low-stress method, she thinks it can be too subtle for some calves.

“It reduces milk feeding by 0.2 litres/day. Some calves don’t eat enough concentrates to compensate and, instead, try to drink more frequently.

“It means there is a five-day lag in their concentrate intakes, and they never quite catch up.”

It is easier to follow a step-down weaning regime in a manual bucket or teat feeder system, says Kat. A whole pen of calves by can be weaned by reducing the litres fed week by week.

For instance, she says that 3 litres fed twice a day can be dropped to 2 litres twice daily the next week, and the week after that to 2 litres fed once a day.

The calf is not stressed by this, as the big steps down in milk are replaced by big steps up in concentrate intakes.

© MAG/Shirley Macmillan

For success, it is essential that there is a corresponding greater intake of starter feed as milk feed is being reduced.

Each calf should be eating 3kg/day of an 18% protein for three consecutive days prior to weaning, says Kat.

This is achievable, she maintains, but points out this is why it is important to offer starter feed and water from day one. In the early days, a calf will take only grams.

However, they are learning what hard feed tastes like, and by five to seven weeks, they are eating higher volumes.

Drinking water

Lack of water availability limits starter intakes – Kat likens it to humans eating dry crackers.

“They need three to four times the volume of water [to starter feed], so this means about 10-12 litres of water for each calf every day.

“A group of five calves on Wydale feeders will be drinking at least 40 litres a day – especially in hot weather.”

Palatability of water is also crucial: young calves must be given mains or treated borehole water because untreated sources can be tainted or have mineral imbalances, which puts calves off drinking.  

To physically encourage them to drink, there must be sufficient trough space (or multiple bowls) to allow group drinking without being bullied.

Nipple drinkers are now being used on some farms, although Kat points out that calves have to learn how to press the nipple drinker to access water.

All sources of water must be at an accessible height so that calves can reach, she says. Because this tends to also be the height at which they can muck into them, regular cleaning is essential.

Getting weaning wrong often results in some form of disease that is more noticeable than a check on growth rates, particularly when youngstock are not regularly weighed.

Coccidiosis and pneumonia are common two weeks after weaning, says Kat. “Or calves may look OK and survive, but you are not getting the most out of growth that there could be.

Then they might be moving sheds, mixing in large social groups, and perhaps with more staff and less experienced stockmanship, there is more risk of setbacks going unnoticed.”

Post-weaning scour

Scour is also possible, although there can be multiple causes of this at weaning.

These range from diseases such as coccidiosis to nutritional upsets caused by the gut biome not having had time to stabilise, the introduction of grass silage in a post-weaning diet, and acidosis.

She says hungry calves will gorge on starter feed, then go off it because they feel ill, before returning to gorging again. This triggers acidosis and leads to scour.

Supplying feed ad-lib and fresh at all times will help prevent this happening. “There is an art to having a little bit left in the trough and it is still fresh, not old and stale,” she adds.

Discussing a structured milk feeding plan with the vet, which includes a calculated step-down weaning, will maintain those efficient, cost-effective liveweight gains generated by feeding more milk, says Kat.

In turn, this prevents losses in welfare, setbacks in performance and extra rearing costs.