Early antibiotic treatment is effective in clearing up the bacterial component of pneumonia, but deciding when antibiotic treatment is required can be difficult.
Clearly calves that stop eating and show increased respiratory effort need treatment, but many others will experience only a mild illness lasting a few days.
The concern for those working with an outbreak is that they may misinterpret the signs of advancing illness and fail to treat calves soon enough.
There are two commonly used strategies to address this.
First, where the handling facilities are good and there is adequate labour, the group of affected calves can be led through the crush and temperatures taken.
Calves with a temperature of 39.5C or above should be treated with antibiotic.
This procedure is repeated daily until no more cases of pneumonia are detected and the outbreak is deemed over.
This level of husbandry may stretch labour, but it does have the advantage that the calves’ needs are seen to and the use of antibiotics is beyond reproach.
The alternative approach is termed metaphylaxis.
When the unit is in the midst of a significant outbreak of pneumonia a decision is taken to treat the entire group of calves with antibiotic.
Suitable antibiotics have two or preferably more days of action after one treatment.
The entire group may be treated for a second time depending on the antibiotic selected.
The group is then monitored and any calves still ill are treated again.
Not all calves make an uneventful recovery.
Where there has been significant lung damage, treatment with antibiotic may be required for prolonged periods.
Some affected calves may benefit from medicines that reduce pain and overcome some of the adverse effects of the body’s response to the disease.
No matter whether the farm’s vet advises daily assessment and treatment for individual animals or group metaphylaxis or treatment, there should be clear written guidelines to ensure the outbreak is managed to maximise calf welfare.
Once the outbreak is under control a proper assessment of the role the various contributory factors have played must be made.
This will involve a full review of calf management to embrace feeding, group size and group makeup, how stressors were managed and an assessment of building ventilation.
The unit’s vet will be familiar with the techniques for assessing adequacy of ventilation.
Before the next pneumonia season or next group of calves come into the system a pneumonia prevention plan should be in place.
Vaccination is a key part of that plan.
Vaccination for respiratory syncytial virus (RSV) is essential in all systems and parainfluenza 3 (Pi3) is required for younger calves.
When calves are bought, then infectious bovine rhinotracheitis (IBR) vaccination is also required.
Many of the multi-agent vaccines also include cover for bovine viral diarrhoea (BVD) and this is required in a unit where cattle are bought or the adult herd is not vaccinated against BVD.
Ultimately, the unit’s vet will be able to advise on the best vaccination programme.
Whatever vaccine is used it is important to complete the course before the pneumonia season begins.
This may be difficult for dairy-bred or late autumn-born beef calves.
Strategies are available to help in this respect, but the challenge of controlling pneumonia is greatest in these younger calves.
With proper planning severe pneumonia outbreaks can be prevented and calf health and welfare maximised, with a clear and beneficial effect on unit productivity.