Pneumonia: predict and prevent
It must be the weather! We have seen a massive increase in pneumonia in calves and youngstock over the last month. Even some adult cattle have been affected. The weather certainly plays a part: cold damp air is stressful to cattle, but very hospitable to the organisms that are involved in Bovine Respiratory Disease (BRD).
BRD is a complex disease, involving several viruses, mycoplasmas and bacteria that often work in combination to create disease. These organisms do not survive long outside the animal, so disease is perpetuated and spread from carriers, which are often symptomless. A clean environment such as a disinfected shed is of little use in preventing respiratory disease.
The organisms spread from carrier animals to susceptible ones by contaminated air, with water droplets contained in it being the perfect vehicle for transmission. Cold, damp air containing infectious water droplets in a confined space is a perfect combination to spread pneumonia pathogens: such conditions should be predictable and preventable.
- Pathogens survive longer in colder environments. Carrier animals that are shedding organisms are much more infectious in cold conditions.
- Cold air has much less capacity to evaporate moisture, so cold air is generally damp air, giving organisms a vehicle to transmit between calves.
- Young calves are stressed by cold: air temperatures below 9oC will stress calves unless they can create their own microenvironment to keep warm. Many sheds fall below this temperature, particularly at night.
- A lot of water goes into a calf shed: ten pre-weaned calves consuming just 10 litres of milk per day will put one tonne of water into the shed in just ten days. If it can’t drain out, it will inevitably create moisture in the air and water droplets to transmit organisms. Evaporation rates are very low on cold damp days.
- Leaking gutters, horizontal rain, overflowing water troughs add to the moisture load.
- Bedding only absorbs and holds the moisture: it does not get rid of it.
- Beware of straw choppers and mechanical bedders: these create dust, often contaminated with mould spores, which destroys the animals’ natural defences against respiratory pathogens and can themselves cause respiratory disease.
- Close confinement makes transmission easier, creates more moisture and increases the pathogen load in the air:
- Ventilation must not be confused with draft: every building needs ventilation to allow foul air out and clean air in, but without chilling the calves.
- Specific floor and air space requirements and the size of ventilation gaps required for any sized shed are available on myhealthyherd.com
Predict and prevent BRD:
- BRD is preventable. Predict when and how it is going to happen and take action before it starts. Once it is established, carrier animals persist and continually re-infect susceptible ones.
- Treat early at the first signs to reduce the number affected and reduce the infective load: get advice on what to treat, and how to treat. Consider using prophylactic treatment on animals in contact or in very early stages of the disease.
- Keep calves warm: deep dry bedding is essential, and in cold shed, the bedding should be deep enough so that the calves’ legs are not visible when they are lying down (and calves spend 90% of their time lying down).
- If you can’t keep the bedding deep, use calf jackets to keep calves warm.
- Consider vaccination to increase the animals’ resilience to infection: vaccination may not prevent all pneumonia, but it dramatically reduces the effects and damage.
There has been a manufacturing fault with a batch of Synulox Lactating Cow mastitis tubes. The entire production has been recalled, and a replacement product is as yet unavailable. We have contacted all those that have purchased the relevant batches (which has justified our onerous recording system). Please return the product and we will provide a suitable replacement. This might provide an opportune time to review first and second line mastitis treatments to make the best use of the available products.
Sheep issues: neonatal lamb losses
Almost everything that goes wrong with a sheep happens around lambing. Dead lambs are a dreadful waste of all the effort and resource that has gone into getting them to the point of birth. Neonatal mortality is preventable and often predictable.
E.coli is an opportunist organism that tends to build up in the environment from faecal contamination. New-born lambs rely entirely on colostrum for protection against pathogenic strains of the organism, and so E.coli infections in all their guises such as watery mouth, septicaemia, scour etc, can be prevented by high quality colostrum and good hygiene.
E.coli infections can be predicted by watching for:
- Build-up of infection in a contaminated environment – dirty lambing pens!
- Poor quality colostrum – inadequate nutrition of pregnant ewes
- Contaminated udders – dirty sheep
The solution to E.coli is not mass medication, but reducing the challenge and increasing the resilience of the new born lamb. If antibiotics are needed, we may require some samples before prescribing the appropriate drug to reduce the risks of resistance and increase the effectiveness of treatment.
Watch out for:
- Joint ill and septicaemia, caused by streptococcus or erysipelas
- Toxoplasma and Enzootic abortion, nutrition and mineral deficiencies – causing premature lambs, poor colostrum and weak lambs
At the Farmer Meeting in February, we will give some guidance on making a diagnosis using basic examination pre and post mortem, so that you can be sure of what is going on.
Many farmers use ruminal magnets to protect their cows from “wire disease”. These are a simple way of preventing traumatic reticulitis, as most cows are at risk.
Administering the magnets is simple, and cheap. They generally remain in situ for the animal’s lifetime, and we can check if they have been lost simply by using a small compass!
Here is one that was removed from a cow at post mortem: the collection of nails and wires shows what cows manage to eat!