Keep calf performance on track this winter

Ensure calf housing is well ventilated and aim to keep humidity below 65%. Calves should be housed in clean, dry, disinfected pens with plenty of bedding. There should be sufficient straw bedding for calves to ‘nest’ and completely cover their legs, and straw should be changed regularly.

Producers should consider providing younger calves with calf jackets and lowering stocking densities in calf housing to reduce overall infection pressures.

Good colostrum management protocols need to be in place because high-quality colostrum will help calves to develop passive immunity, enabling them to fight off disease. Colostrum must be tested before feeding, with only good-quality colostrum (at least 50g/litre of IgG) fed to calves at a rate of between four and five litres in the first hour of life.

To hit early growth targets and calve for the first time at 24 months old, youngstock must also be supported nutritionally during the winter period, and particularly during cold weather.

When temperatures drop below 10°C this represents most calves’ lower critical temperature (LCT), where their performance will be negatively affected as they divert energy away from growth to keeping warm. This LCT changes with age. Calves up to three weeks old have an LCT of just 20°C.

To combat the negative impact of low temperatures, producers should offer calves additional energy and protein in the form of higher volumes of calf milk replacer. Typically, calves should be fed an extra 0.5 litres of calf milk replacer for every 5°C below its LCT.

Table 1: Increased litres of milk replacer fed per day according to age/temperature

Producers could also implement a winter-feed rate to cover the colder months to maintain consistent feeding. This could mean feeding up to 180g/litre as a feed rate during the colder months to accommodate a range of low temperatures.