Why a simple, repeatable system is key for calf rearing

Attention to detail and consistency are the keys to success with calves, according to consultant vet Tommy Heffernan.

It sounds simple, he says, but in practice, remains hard to achieve for many farmers.

“We know everything we need to know about rearing calves, yet we still don’t get to optimise it or improve it.

See also: Benefits of dedicated calf rearer for split block-calver

“Goals are fine, but you have to create habits. The main thing is to create a simple, repeatable system – it has to be as easy as possible if it’s going to work,” he says.

“With calf health, you’re always trying to do two things: drive up immunity and drive down infection pressure.

“Perfection is not achievable, but what about progress? A small change each year is impactful.”

While the benefits of colostrum – the building block for immunity – are well known, not all farmers realise how variation in a cow’s feed rations will affect colostrum quality.

Changing from one silage clamp to another is a particular risk area, he says.

Stress also has an impact, with heifers “extremely prone” to producing poor-quality colostrum.

“This isn’t fluffy animal welfare – stress has a very negative influence on the immune system and so on colostrum quality,” he points out.

Keep it clean

The young calf gut is primed and ready to take in immunoglobulins provided by colostrum.

But colostrum’s high fat and protein content is also attractive to bugs, which will thrive if it is not promptly refrigerated or frozen after harvest, or if hygiene standards are substandard during collection and storage, Tommy says.

Dump buckets are particularly prone to harbouring bacteria, he adds. They should receive the same attention to detail as the milking machine when cleaning.

Stomach tubes and milk lines in automated calf feeders are other risk areas.

To avoid a biofilm developing in calf feeding equipment, it should first be rinsed with cool water to remove any milk residue.

Then it should be washed with detergent and water above 60C, and hung upside down on an indoor hook to drain.

Tommy advises testing water for coliform count as poor water quality can also add to disease pressure.

Biofilms are at risk of developing in systems with a lot of pipework or poor flow rates, and during warm weather.

Calf sheds supplied by header tanks are particularly vulnerable, he says, as are calves fed milk replacer made with poor-quality water.

How much milk?

As well as quality, the quantity of feed has a direct impact on calf immunity.

Tommy recommends a minimum of 3 litres twice a day but says at times, even this is not enough.

“In a cold spring, 3 litres twice a day is not really doing it,” he suggests, adding that he anticipates ad-lib feeding becoming much more widespread.

He points out that as well as priming the immune system, heifer calves are also laying down mammary cells for the future.

“There is no negative impact of feeding more,” he says. “And don’t worry so much about [whether a milk replacer is based on] skim or whey – the quality of protein and fat is key.”

Warm and dry

Another factor in reducing disease risk is making sure calves are warm enough.

“We underestimate the impact of the cold, but I’m not a great fan of calf jackets – they’re complicated, and there’s the cost,” says Tommy.

As calves spend 85% of their time lying down, he advises keeping a digital thermometer in the calf shed because below 15C, they have to start walking around to keep warm.

He prefers a simple system with more milk to drink and more straw to nest in.

“Get down where the calf is. Is it warm and dry? You can’t beat extra straw, it’s an incredible insulator,” he says.

“At 10C, I’d think about giving more straw, and at 0C, action is needed with extra milk or calf jackets. If you know there’s a cold snap coming, you can add 0.5-1 litre/day, 48 hours ahead.”

Cold, damp straw, by contrast, as well as cold concrete and water spilling from troughs, take heat from the air, and therefore from calves.

“Bugs also like damp, moist conditions, so get the moisture out of the shed,” Tommy stresses.

Fresh air helps keep conditions dry and kills pathogens, but draughts must be avoided.

“The position of the yard will dictate the flow of air, so there is no one-size-fits-all system. Use your nose – if you can smell ammonia, there’s a problem.”

Room to move

Providing enough space for each calf is also critical as a lower stocking density means less disease pressure.

“It’s the biggest factor, so invest in space: you need 2sq m a calf” Tommy explains.

Tommy Heffernan was speaking at the recent Positive Farmers Conference in Ireland.