3 key areas to consider for a successful winter housing period

It is hard to believe that autumn is only around the corner and that it is already time for farmers to put measures in place to prevent pneumonia during the winter period.

Pneumonia is one of the most common health problems affecting cattle and can have a lifetime impact on future production.

Therefore, protecting the respiratory health of youngstock is vital to protecting the future performance of the herd, whether beef or dairy.

Key areas to consider prior to housing are listed below.

Buildings

To ensure buildings function properly and the disease risks from winter housing are minimised, we need to consider ventilation, moisture and wind speed.

1. Ventilation (fresh air)

Viruses and bacteria do not survive well in fresh air. Ensuring good air quality in cattle buildings reduces infectious burdens and promotes lung defences.

To get fresh air into buildings you need:

  • Inlet- somewhere for fresh air to get in;
  • Outlet-somewhere for stale air to get out.

Natural ventilation uses heat generated by cattle inside a building to drive the ‘stack effect’, whereby warm air rises, leaves through the building ‘outlet’, and creates a negative pressure which draws fresh air into the building through the ’inlet’.

During the winter housing period, even on a very still day, the heat produced by the housed cattle should be sufficient to drive the stack effect, ensuring a constant movement of fresh air into the building.

The inlet area is ideally spread across both sidewalls and needs to be at least twice, but, preferably, four times the outlet area.

The outlet in the roof will allow warm, moist, foul air to escape. The rule of thumb is the outlet area needs to 0.1m² per growing or adult animal¹.

2. Moisture

High levels of moisture in a building increases both the survival time and spread of pathogens, both in the air and in the bedding. Moisture also increases requirements for bedding.

Some obvious areas to look at addressing include repairing leaky downpipes, and broken leaky/overflowing water feeders, and ensuring pens are sloped so they can drain adequately.

During the winter housing period, when cattle are inside, avoid using excess water to clean feed areas as this raises moisture and humidity levels in the shed.

3. Wind speed (draughts)

Whilst good ventilation and fresh air are vital, this air flow needs to be uniform and draughts must be avoided particularly when housing young calves.

Too much air speed is associated with excessive energy losses which can lead to the need for higher feed intakes or low production rates in addition to health problems. At the other end of the scale too little airflow can also have adverse health effects.

As a short-term measure, large straw bales can be provided to offer some shelter from draughts. For longer term measures, investment in permanent windbreaks should be considered. Windbreaks must be kept clean for them to function as an effective inlet – if the gaps become blocked with dirt or vegetation, ventilation will be affected.

Now is the time for farmers to appraise their buildings with a critical eye and pose the question: Are they truly fit for purpose?

If not, what changes can be made to reduce the risk of disease in their animals during the winter housing period? In some cases, small and inexpensive alterations can have a very positive impact on animal health.

Parasite control

Another area to consider prior to housing is how to control parasites, specifically fluke and worms. All parasites have a negative effect on the cattle’s immune system and lungworm, in particular, can damage the lungs and increase the risk and severity of bovine respiratory disease (BRD).

Treatment for lungworm ahead of housing allows time for dead worms to be coughed up. The benefit of this pre-housing dose is that all the worms can be removed from the animal, and the lungs can fully recover from the damage that the worms inflicted while they are still out in clean fresh air.

When they are housed they will have a clean, healthy set of lungs to combat the dust and viral infections they will encounter in the shed.

Moxidectin (Cydectin) and doramectin (Dectomax) offer persistency against re-infection by stomach worms (ostertagia) and lungworm (dictyocaulus) of five weeks from a single dose.

Therefore, animals treated with either Cydectin or Dectomax five weeks before housing will not need to receive another dose at housing.

Vaccination

Vaccination plays an important role in protecting respiratory health; it shouldn’t however be viewed as the silver bullet to solving all health problems. Vaccination must be combined with good farm-management practices like those listed above.

Viruses such as RSV, Pi3 and IBR can act individually or in combination to cause significant lung and airway damage, reducing the animal’s resistance to secondary bacterial infection.

These three viruses are the most important primary pathogens. Once the viruses have caused the primary damage, the bacteria can enter as secondary invaders resulting in extensive damage to the lungs.

BVD virus can act as an important trigger because it suppresses the immune system and opens the door for the other agents that multiply and cause disease.

So, by protecting against the four key viruses, we can significantly reduce the number of pneumonia outbreaks.

Rispoval 3 protects animals against RSV, Pi3 and BVD. Protection lasts for up to six months.

For cattle over three months-of-age two doses of vaccine should be given 3-4 weeks apart and, ideally, weanlings should complete the vaccination course at least three weeks before any stressful event such as housing.

For more information on Rispoval 3 click here

For a quicker onset of immunity cattle can be vaccinated with an intranasal vaccine. Rispoval RS +Pi3 IntraNasal protects against RSV and Pi3 within five to 10 days. Protection from a single dose lasts for 12 weeks.

For more information on Rispoval RS +Pi3 IntraNasal click here

Rispoval IBR-Marker live gives protection against IBR for up to six months. Given intranasally it is licensed for cattle at immediate risk of IBR (followed by an intramuscular injection 3-5 weeks later).

For more information on Rispoval IBR-Marker live click here

Alternatively, a single intramuscular injection given three weeks prior to housing will ensure cattle are protected throughout the housing period

Poor respiratory health can impact both growth rates and feed conversion efficiency, resulting in losses through, for example, increased feed costs, increased finishing times, reduced sale weights, or increased age at first calving in breeding animals.

Winter is coming, and now is a good time for farmers to put the appropriate measures in place to help keep their animals healthy throughout the winter housing period and avoid the long-term drain on performance.

Reference

¹Jamie Robertson presentation Livestock Northwest