Are your calves ready for winter?

With December fast approaching, dairy farmers are being urged to act quickly and ensure that their calf rearing systems are ready to deal with winter’s challenges. We caught up with ForFarmers’ Youngstock Manager, Ann Coombes, to get her advice on what a ‘winter-ready’ calf rearing setup should look like.

Calves in shed Header 2048 1024 px - ForFarmers UK

Calves represent the future of any dairy herd, so ensuring good calf health all year round should always be a key priority. Winter in particular poses unique challenges, with calves coming under increasing health and performance pressures as a result of worsening weather and declining temperatures.

To help mitigate against the negative impact created during the winter period, it’s vital that calf rearing setups are in top order, with producers paying particular attention to feeding, housing and hygiene protocols.

“If we want calves to get off to a good start in life, hit early growth targets and be ready for first calving at 24 months or under, it’s really important they’re properly supported during the winter period,” explains Ann Coombes, ForFarmers Youngstock Product Manager. “Now’s the perfect time for producers to look at their calf rearing setups, identify any weak-points and rectify these before winter hits.”

Housing and bedding

Traditionally, cold stress has been one of the biggest challenges that calves face over the winter period, with declining temperatures forcing a calf’s energy reserves away from growth to focus on keeping warm.

“However, we’re now witnessing a trend of warmer, wet winters, which are starting to make cold stress less of an issue,” explains Ann. “Instead, these changes in weather conditions are increasing the risk of pneumonia, which is the second biggest cause of calf mortality in the dairy sector.

“One of the ways to combat this increased risk is to ensure that calf housing has adequate levels of ventilation to prevent the build-up of stale air and harmful pathogens. It’s important that housing has enough air inlets and outlets to aid natural ventilation, with a goal of helping to keep humidity levels down below 65%.”

Carrying out a smoke bomb test can identify air movement and ventilation ‘dead spots’ in calf housing, as well as any draughts that might be occurring at calf height. The aim is for smoke to keep moving through housing and gradually clear within 40 seconds.

Smoke bomb test CTA Block Text media 1140 wide px

“When there’s an increased risk of pneumonia, it’s also worth lowering stocking densities in calf housing to decrease infection pressure,” continues Ann. “It’s also important to ensure that calf pens are kept clean, with bedding that’s dry and changed regularly. As soon as calf’s get cold and wet, they are far more susceptible to illness or disease.

“To assess whether bedding needs changing, carry out the knee drop test. Producers should kneel in bedding for 30 seconds and when they stand up, if their knees are wet, then the bedding needs changing. Calves should have enough bedding so that they can form a deep nest, completely covering their legs when lying down.”

Ann also recommends that specific cleaning protocols are put in place for calf pens, with disinfectant used to clean housing between batches of calves.

“Identify specific bacterial challenges on farm and then select the right disinfectant to combat these. When it comes to the actual cleaning process, it’s important to use a steam cleaner or power washer, and plan to leave pens empty for seven days between batches of youngstock.

“There are also some fantastic new innovations with heating equipment used in calf housing, but be sure that any areas where this equipment is used are kept clean and dry to avoid the spread of bacteria.”

Knee drop test CTA Block Text media 1140 wide px

Feeding and colostrum management

When temperatures do decline enough for calves to start suffering from cold stress, extra supplementary feeding is key to maintaining good calf performance.

“Cold weather becomes a negative factor in most calves when temperatures hit below 10°c,” continues Ann. “This temperature represents a calf’s Lower Critical Temperature (LCT), where calves will start to divert vital energy away from growth to keeping warm. This LCT changes with age, with calves up to three weeks of age having an LCT of just 20°c and newborn calves exhausting their energy supplies within the first 18 hours of life if constantly exposed to cold temperatures.

“Even in more mature calves, animals can go from strong growth gains into negative energy deficit and declining growth rates in a relatively short timeframe due to cold weather. To combat this, I’d recommend providing extra energy and protein to calves in the form of extra milk replacer. This could be achieved by increasing the litres of milk fed to a calf by 0.5 litres, but if temperatures are below 0°C I would suggest feeding an extra 1 litre per feed. Some farmers prefer just to use an elevated winter feed rate that they implement throughout colder periods, simply increasing the amount of calf milk replacer fed per litre during the winter months - for example increasing from 150g/l to 180g/l.”

Increased litres of milk replacer fed/day according to age/temperature:

Ambient temperature

Below 3 weeks of age (50kg)

Above 3 weeks of age (65kg)





0.5 litres



0.5 litres



1 litre

0.5 litres


2 litres

1 litre


3 litres

2 litres

“Colostrum helps calves battle pathogen and disease threat, colostrum management needs a strong focus over winter when there are more health challenges,” continues Ann. “All colostrum needs to be tested for quality using a refractometer or colostrum balls, with only good quality colostrum fed to calves at a rate of four to five litres in the first hour of life. Ideally that would be colostrum containing at at least 50 g/L of IgG.

“Before the onset of winter, farmers should ensure that they have a clean area to test colostrum, as well as facilities to store excess colostrum, either in a fridge or freezer.”

Don’t overlook the importance of calf weighing

Early signs of poorer calf performance can be difficult to spot, especially in older animals, so Ann recommends regular calf weighing over the winter period.

“Regular weighing is one of the best ways to identify calves that need extra intervention over the winter period,” concludes Ann. “If farmers want their heifers hitting good growth rates so they’re in condition ready for first calving at 24 months or below, then they can’t afford to let calf performance be held back during winter.

“Once calves have been weighed it’s easy to spot those that are falling behind. Speedy intervention with extra feed or health care is then much more cost effective than trying to ‘catch up’ daily growth rates, later down the line. If not in place, I’d strongly recommend that farmers pull together a weighing plan for livestock for the coming winter period – it could make a huge difference to calf performance.”

Calf weighing CTA Block Text media 1140 wide px

Get in touch with our dairy specialists

Contact our dedicated team of dairy specialists for advice and how we can help your business.

CTA block dairy 1140 x 1520 px