11 January 2008

4 minute read

Some farmers accept that calves will inevitably go through a prolonged growth check after weaning, however this does not need to happen. Steps taken to improve calf welfare at weaning will also improve the lifetime performance of the animal and boost enterprise profitability.

What are the stresses that affect calves around weaning? It is important to see things from the calf’s perspective.

Stressors

• Transport or travel from field.
  
• Treatment in handling pens.
  
• Change of environment – field to pen.
  
• Mixing with calves from other groups.
  
• Loss of contact with dam.
  
• Big change of diet – used to 6 litres of milk per day, accounting for 25% of its energy intake.
  
• Unfamiliar feeds – unused to forage and sometimes cereals.
  
• Respiratory problems from poor ventilation.
  
• Exposure to transfer of disease from older animals.

What can we do to minimise stress?

Some of these stresses are unavoidable but others can be reduced or spread over a longer period to reduce the overall impact. The following are techniques that can be used to reduce stress.

Heavier calves cope with stress better than lighter calves

How do you get heavier calves, without changing calving date or age at weaning? Improve suckler herd fertility and ensure that two thirds of your calves are born in the first 3 weeks of calving. A calf born in week 2 of calving is 28 days older than one born in week 6 and is likely to be 30kg heavier at weaning. Information on tightening the calving spread can be found in the QMS publication “Improving Suckler Herd Fertility”, available through all SAC Offices.

Delaying weaning is not really a solution, since this will often pull down the condition score of the cow, affecting its welfare and future fertility.

Creep feed reduces stress and risk of pneumonia

Young calves, reared on a diet of milk and grass have a limited rumen capacity at weaning. This limits their forage intake and places a higher reliance on growth off concentrates. This transition is best handled by offering creep feed, either for a minimum of 6 weeks before weaning, or ideally 10 weeks before weaning. The 10 week option is likely to increase weaning weights by 25kg, and post weaning gains by at least 10kg, at a time when feed conversion is at its most efficient at around 5kg feed per kg liveweight gain. Creep fed calves will suffer less stress at weaning because they have already adjusted to a concentrate diet, and will be less susceptible to pneumonia. Gradually mix the housing concentrate in with the creep so that calves are on their post weaning concentrates two weeks before weaning.

Offering roughage before housing/weaning

Offering either silage or straw as a supplement to cows and calves pre-weaning helps calves get used to eating conserved forage before housing.

Gradual weaning techniques

I have seen a number of these systems used on farm with good success. The easiest of these methods is to wean most of the calves at housing but to leave a few of the fitter cows that can afford to lose a bit of condition in with the calves for a week or so after weaning. This helps calm the calves.

Those with a reasonable amount of shed space can set up creep areas in the shed and gradually shut the calves in the creep pen for longer periods over a two week period. The calves will gradually wean themselves.

Another technique involves removing a third of the cows from the cow and calf group every week. Removing 12 cows from a group of 35 cows and calves, means that 23 calves will still be with their mothers and behaving normally which tends to calm the weaned calves. By the time the next 12 cows are removed from the group, the first weaned calves should be calm, and so on. This works well when weaning co-incides with housing.

Pecking order

Weaning usually involves the stress of mixing calves from different groups to form batches of steers and heifers. The key thing is to form even batches because it is always the smallest calves in the group that will either be bullied or feel intimidated about going to feed, and be most susceptible to stress. These problems are greatest in big groups so limiting group size initially can also help. Again, if you have a compact calving your calves will be a more evenly sized and pecking order problems will be limited.

Housing

Always house your newly weaned calves in a separate shed to avoid contact and spread of respiratory disease from older to younger animals. Weaned calves should be housed in your best ventilated shed. Calves should always be housed when coats are dry, preferably at a low stocking rate.

Treatments

Try to spread out treatments to avoid too many treatments at weaning – worming and respiratory treatments can be phased in before housing. Veterinary treatments are covered in a separate section. Calves should be castrated using rubber rings shortly after birth – the belief that leaving male calves entire improves their growth rates up to weaning is completely wrong. Delayed castration causes a severe growth check.

January 2008