Managing calves through summer
While steps are often taken to reduce heat stress in milking dairy cows, it is important not to forget the impact of heat on calves.
Acalf’s thermoneutral zone is between 10-25degC and, while they tend to cope better with heat than adult cattle, they will become heat stressed if the temperature rises above this level.
This can increase the risk of dehydration, reduce feed intake and cause stress, lowering immunity. All of this can impact on average daily weight gain, risk of disease and even mortality. Longer term, this can also affect breeding size and age at first calving.
High humidity and poor airflow can increase the chance of pneumonia and, in heavily stocked buildings, can cause heat stress in cooler months as well as in summer.
Kirsty Ranson, of Westmorland Vets, says: “One of the real challenges is managing calves if the weather is fluctuating between extremes with cold nights and very warm days, particularly if you are using calf jackets, so it is important to monitor calves and their environment closely.
“In hot weather, it is critical calves take on enough fluid so they do not become dehydrated.
“They have a very strong sense of smell and taste, so it is vital to ensure water is not tainted and is clean, fresh and palatable at all times. Make sure you have a good fly control practice in place, as not only do they spread disease, if calves are bothered by flies, it will suppress their appetite.
“In summer, it may be possible to move calves to better ventilated buildings which have been vacated by older cattle providing they have been thoroughly cleaned, disinfected and left to dry beforehand. This will give the chance to thoroughly clean and disinfect calf housing and leave it empty for a while, which will help reduce disease challenge for future months.”
SIGNS OF HEAT STRESS IN CALVES
- Reduced movement
- Faster breathing
- Panting
- Decreased feed intake
- Increased water intake
ENVIRONMENT
- If calves are housed in hutches outside, open as many vents as possible; propping up the back edge of the hutch will allow for increased airflow
- Make sure hutches are well spaced out so air can circulate between; if calves are outside, they must have access to shade
- Make sure any buildings housing calves are well ventilated and consider using fans if necessary, but ensure there are no draughts at calf level
- While roof lights can reduce the need for artificial lighting, they can increase the heat in a building if fitted on a south-facing aspect; it is therefore recommended that roof lights are fitted to the north-facing aspect of a livestock building
- Make sure bedding is clean and dry at all times, as warm, damp, soiled areas will encourage the growth of bacteria; similarly, clean and disinfect all feeding equipment daily
TOP TIPS
- Monitor temperature in the calf housing daily at calf level
- Monitor calves for sweating, panting and drinking excessively
- Change water frequently and keep out of sunlight
- Reduce stocking rate
- Increase airflow in housing being careful to avoid draughts
- Provide shade
- Control flies to reduce disease spread risk
- Routine procedures, such as vaccinating, should be carried out in the cool early morning or evening
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