Respiratory Conditions In Older Cattle

Over the last couple of months I have seen some severe respiratory conditions in older cattle. Usually, we think of calves as being most vulnerable but there are a few problems that can crop up in older animals this time of year.

Fog fever is one, which can be tricky to diagnose since it has similar clinical signs to lungworm (which is far more common). It’s been a bad year for lungworm, so testing any older animals you see coughing and scouring is well worth it, particularly if they have seen limited grazing or heavy wormer use.

Grass during the autumn regrowth can have higher levels of a protein, which is converted into a toxin in the rumen. This leads to the typical signs of sudden onset, severe respiratory distress and increased effort such as grunting and frothing. Treatment is not very successful and prevention is much more economical.

The best way to prevent fog fever is to graze pastures before they become too lush, or to introduce the new diet slowly and give animals’ rumens time to adapt. Just don’t forget to rule out more common conditions like IBR or lungworm first!

Some welcome extra grass growth has extended the grazing season for some farms. But sooner or later most herds will come indoors and enter an environment with its own challenges from a health perspective. Pneumonia takes advantage of the stocking density, humidity, reduced ventilation and other stressors associated with winter, such as diet changes and cold weather.

Controlling the above factors as much as possible is essential, alongside ensuring effective colostrum transfer to newborns. Other measures we take, such as vaccination, will be less successful until we get the management right. However, an increasing number of suckler herds are vaccinating against pneumonia, and the different products can all be beneficial if used in the right circumstances. I would always recommend doing some testing before vaccinating (on either live animals or postmortems), to ensure we select the right one for your herd.

The table below summarises the commonly used vaccines. The important thing to note (for anyone needing protection at the start of housing), is the duration between the first injection and immunity actually developing- start too late and you may see pneumonia during the transition.

IBR Marker Live

Adults can suffer from IBR as well as calves, and some herds are vaccinated every year. Clinical signs include nasal discharge, coughing, conjunctivitis and a fever which can lead to abortions. A second intranasal or injected dose will prolong immunity for up to 6 months.

Respi 3 & 4

Respi 3 will cover for the viruses PI3 and RSV and the bacteria Mannheimia. Respi 4 protects against the same bugs as Respi 3 but also provides cover against BVD, which is useful in systems that buy in calves from sources with unknown BVD status. A further vaccine after 6 months will prolong immunity.

Bovalto Intranasal

IBR Marker takes two weeks to give proper immunity, and Respi 3 and 4 a total of five weeks from the first injection. This can be significant if pneumonia appears suddenly or too quickly for other vaccines to be effective e.g. within a few weeks of buying in. Bovalto Intranasal gives immunity within ten days. The shorter 3 months duration may be enough if housing is your main risk period.

Other infectious agents are possible, including other bacteria (particularly in finishing units) and Mycoplasma. Vaccines for Mycoplasma and the combination of Histophilus and Mannheimia are available if these have been a specific problem in the past.

Talk to your vet if you have any questions about vaccination or would like to do some diagnostic testing first- remember, the Animal Health and Welfare Pathway grant would be an excellent way of establishing which bugs are on farm to inform vaccine choice and avoiding costly pneumonia outbreaks over winter.