Technical Day: All aspects of calf health up for discussion in Co. Kildare

Peter Byrne’s farm, located just outside Castledermot, Co. Kildare, was the chosen farm for a recent Teagasc Green Acres Calf to Beef Programme technical day.

The main topic up for discussion was calf health and the key messages were delivered by well-known vet, Martin Kavanagh.

Kicking off the talk, Martin noted that the use of antibiotics in Ireland is going to become more limited, and farmers will have to look beyond treatment and focus more on preventative measures.

“If we’re looking at calves coming in and pneumonia; it’s really about the interaction of the calves themselves, the environment and the bacteria and viruses that are involved.

“The problem is that we are taking a calf that has gone through stress at some point – they may not have got enough colostrum resulting in a poorer defense mechanism,” he explained.

Realistically, we will have to start looking at what happens on the home farm, otherwise you will be getting calves that are not fit for purpose.

In terms of financial costs associated with a pneumonia outbreak, Martin highlighted that affected calves could lose up to 200g/day in growth, and that slaughter date could be delayed by up to 60 days.

“Calves have a very small lung area compared to other animals; so, if you knock out some of their lungs, their ability to eat as they get older decreases, so dry matter intake (DMI) is less – resulting in less thrive,” he added.

Calf arrival management

The number of farms from where the participating farmers in the programme sourced their calves in 2019 varied. Some purchased calves directly off-farm, more attended marts and some used the services of calf buyers.

Ideally, calves should only be purchased from known sources, with direct off-farm purchasing preferable. This is one aspect that the participants will work on going forward.

Martin outlined a number of management practices that should be carried out when the calves land on the farm. These include:

  • Eye and skin test – to see if they are dehydrated;
  • Calves should be kept in the same group;
  • Deep, warm straw bed;
  • If it’s cold, heat should be added for young calves.

“If a calf is hydrated, it should have a full, bright eye. The skin test involves pulling back the skin; if it bounces back the calf is hydrated. If it is slow to do so, or folds, electrolytes are needed.” Martin said.

Calf environment

Providing the correct housing environment is central for a calf to reach its genetic potential and to avoid stress and health issues. Inadequate housing can be linked to increased incidents of respiratory disease and scours.

“If you have 100% fresh air on calves, it’s 10-20 times better at killing the viruses than 50% fresh air. Fresh air actually deals with viruses; they cannot survive for a long time in air that is being refreshed all the time,” he explained.

“We have to be able to take all of the air volume out of the house and it has to be replaced with fresh air 4-5 times/hour.”

However, discussing the challenges with calf housing in particular, he said:

“Calves don’t produce enough heat and the level of air lifting up through the top of the shed is low. They should spend 80% of their time lying down.

“Draughts and down draughts lead to chills. Calves up to three weeks-of-age grow best between 15º and 25º.

“If we have draughts and a calf’s temperature drops below 4-5º, they start to burn a huge amount of energy to keep themselves warm, and that’s where we get significant pneumonia problems because they are running out of energy.

“This draught is a real problem if you have an 8ft shutter, which is the way most sheds are built. The air ‘falls’ over at high speed – the higher the wall, the faster the air will over the top of it.

“So, your standard calf shed is either no air moving at all, or too much air creating problems,” he added.

Pointing to University College Dublin (UCD) research, he explained that air has high levels of bacteria at bed level and it is this air – at calf level – that is the problem.

Offering solutions, Martin provided at number of options, including:

  • Yorkshire boarding;
  • Vent sheeting;
  • Dry straw lie;
  • 1:20 sloped floor;
  • Adequate space. 

“We can slow down the air speed with yorkshire boarding or vent sheeting. Yorkshire boarding is 25% open and it slows down the wind speed. However, if you are on a very exposed site it can lead to a lot of draughts.

Yorkshire boarding won’t fix every house.

“Vent sheeting is 10% open, so this can be used on a very exposed side and take it off at the leased-exposed side, because it doesn’t let in or out enough air.

“Vent sheeting can be useful, but in general it is very poor on calf sheds – particularly when its on top of an 8ft shutter.

“You have to be careful that one size does not fit all; it all depends on the way the shed is orientated. This is the problem; one plan will not build a calf shed – you can’t do it that way.”

Touching on space requirements, he said: “For young calves – up to three weeks-of-age – 1.5m² is enough, but when they get older they need more space. With automatic feeders, you need 3-4m² and with teat feeding systems you need 2.5m²/calf.”

Feeding calves

Martin also discussed how to feed calves in detail.

“Firstly, a good-quality milk replacer, well-acidified and clean equipment is essential.

“Mixing milk replacer at the wrong temperature is a big big issue – it’s inconsistent. Feeding it warm in the morning and cold in the evening won’t work.

“A 22-23% protein replacer at 18% fat, with protein and energy coming from milk sources is going to be OK.

“At weaning, calves should be eating 1.5kg of concentrate at least, and to do this they need a body weight 85-90kg plus.

“At eight weeks-of-age, we need the calves to be double their birth weight – and that’s why we need to weigh on arrival. If you double the birth weight at eight weeks, you can start to reduce milk and add more concentrate,” he explained.

“We don’t want calves on milk for 12-13 weeks; there’s no need and it’s too expensive. However, if we miss out on the early milk growth stage, we actually end up in trouble at the other end in terms of finishing.

“The milk phase is where we get the highest feed efficiency and growth rate – its the cheapest growth you can put on, even though you have the most expensive feed.”


There are several pneumonia vaccines on the market today. Some are for the common bacteria that cause pneumonia, such as Mannheimia (formerly known as Pasteurella) and others are for respiratory viruses that cause pneumonia (IBR, BVD, PI3, BRSV).

There are also intranasal vaccines that can be used in young calves to prevent pneumonia and are a benefit to many calves.

When it comes to buying in calves, ideally I’d like vaccination to be done on the dairy farm that they are coming from.

“However, if not, I’d leave 24 hours to get them in and warmed up, get them fed and go with intranasal,” he added.

Responding to the question – is all vaccination needed if housing and management practices are good, he said: “I think if you can get a lot of the system right, a lot of the vaccines become unnecessary, but the problem we have in Ireland is that a lot of these diseases are endemic.

“What I say is, start with the basics, get an RSV, Pi3 vaccine in at a minimum – get that into the calves; after that, it’s down to diagnosis – what have you actually got,” he said.

He also noted that de-horning and vaccination at the same time should not be practiced.

Why is cleaning equipment important?

Commenting on hygiene in the calf house, he said: “With feeders, the first thing to do is wash the milk out of the feeder with cold or lukewarm water; that will take a lot of the milk out, but it won’t take the fat off it.

“If you use 70-80º water, you will burn all of the fat and protein onto the plastic; you will create a bio-film – super hot water directly onto milk is not a good idea.

“I’d then get a large barrel, fill it with cold water and put peracetic acid into it and drop the feeder in and leave it for three-to-four hours; the peracetic acid disappears after approximately four hours. You can take it directly out and feed calves again.

Continuing, he said: “You also have to look at teat quality; once you start to get wear on teats, you have to change them because you get a lot of bacteria on the teat – this cuts down on the level of bugs.

“You might think that these things are not important. However, you can knock 50g of growth out of them by just exposing them to bacteria. These small practices give the advantage; they make expensive replacers work better,” he concluded.