Speaking at a workshop for veterinary surgeons at the farm of Will Corrie and Sons, Crossnamuckley Road, Newtownards, Aurelie Moralis, veterinary surgeon with Zoetis said: “The UK has approximately ten million cattle and each year 1.9 million of these are affected by respiratory disease. Bovine Respiratory Disease (BRD) or calf pneumonia is the largest known cause of mortality in calves from 1 to 12 months of age on the island of Ireland.”
She added:“When you consider the cost of vaccination to protect respiratory health compared to other production costs then it is surprising that many farmers do not avail of this protection.
“The percentage of variable costs of milk production which can be attributed to feed is 53% while the cost of herd replacements is 16.8%.
“Compare this to 4% for miscellaneous costs, of which veterinary medicines are only a small part, and you can see that the cost of protection against a disease which has such an impact on the herd is money well spent.”
Poor respiratory health has both immediate and long term costs.
The immediate cost of disease has been estimated at £43 per calf. This includes the cost of weight loss during and immediately after the disease outbreak.
The long term effect on productivity is a result of an increased age at first calving, a reduction in lactation yields and a reduced longevity by up to 109 days less in milk.
Bovine Respiratory disease is caused by a variety of infectious agents, but the majority of outbreaks start with a virus.
The key respiratory viruses in young dairy calves are BRSv and PI3v. These viruses can act individually or in combination to cause significant lung and airway damage and also reduce the animal’s resistance to secondary bacterial infections.
In order to maximise heifer potential and reduce the risk of pneumonia in young calves certain aspects of heifer management cannot be overlooked.
The objective of achieving good growth rates should begin from day one with a minimum of three litres of first milking colostrum within the first two hours of life and ideally followed by a further litre fed at six hours of age.
The essential factors in terms of housing are:
Maintenance of gutters and downpipes, mending leaking water troughs and ensuring urine drains away from the bedding will reduce overall moisture levels.
The viability of bugs is negatively affected by clean fresh air.
Control of airspeed
Whilst it is essential that fresh air is available in a building, all possible steps must be taken to avoid wind chill, particularly in calf housing. A draught will increase stress levels and lead to depressed immunity, leaving the calf more susceptible to disease.
In very young calves the lower critical temperature of 15°C is another important factor, since below this calves have to utilise energy to stay warm
Key considerations for vaccination are:
Cover most likely pathogens for the full risk period
Calves can be vaccinated against the two key respiratory viruses BRSv and PI3v from nine days of age with Rispova IntraNasal which will protect them for 12 weeks, ensuring calves are covered through the critical pre-weaning period when poor respiratory health can impact growth rates, age at first calving and subsequent milk yields.
Where required there is the option for ongoing protection against BRSv and PI3v as well as IBR and BVDv from 12 weeks of age with Rispoval®4.
Vaccinate all calves in the same airspace
By vaccinating a group of calves against viral pneumonia it will not only increase the individual calf’s immunity, but will also reduce the amount of virus the calves breathe out, hence reducing viral levels in the shed.
This will decrease overall challenge levels and reduce the risk of a pneumonia outbreak.
Get immunity in place before the challenge and avoid vaccinating during periods of impaired immune response.