It is well recognised when dealing with problems on the farm to start with the premise that “common things are common”.

So at this time of year when we see dairy calves going backwards on grass we will be very suspicious of worms or coccidiosis. This is particularly the case with symptoms such as scouring, appetite and weight loss.

Most farmers will first respond with a worm dose and follow up with a coccidiosis treatment. When the response is not what might be expected, samples may be taken and this is where I’ve seen these cases to fall into the remit of “summer scour syndrome”.

With weaned dairy calves scouring and going backwards on grass, the main differentials will be roundworms, lungworm or coccidiosis.

With lungworm you would expect to hear a cough and probably would not expect scouring.

With coccidiosis, you can see calves losing weight, scouring and they often have a bloody or black appearance. I have seen calves with pneumonia to pine and go backwards over the first months of grazing.

Other more obscure conditions can be giardia (parasite) or molydebenmoisis (too much molybdenum causing copper to be locked up). Sometimes mineral issues can also cause a lack of thrive, in particular high molybdenum locking up copper. These calves can often have poor dull coats and are scouring.

However, over the last four to five years, I see an increased number of dairy calves with none of above conditions but pining away at grass.

There are a number of theories why this might be occurring from poor and early weaning to some issues with lush grass on the young, developing rumen

This week, I heard of two farmers reporting these symptoms, dairy calves scouring going backwards, with some presenting with ulcers in their mouths. What is happening if these calves are not thriving and are scouring but not responding to the usual treatments?

Weight

A lot of the calves will keep losing weight and will eventually die if we don’t intervene. When we examine these cases, they can have ulcers in the mouth and often on post mortem the rumen papillae are not fully developed.

I have often used rumen buffers on these calves combined with rehousing and younger calves going back on milk. Some of these calves never quite recover, but those that have early intervention usually recover slowly.

Very sick calves require fluids, painkillers but even with aggressive supportive therapy, they can be very difficult to save.

It is difficult to figure out what might be happening, when not all calves are affected, or farms are only sporadically affected.

When I see these cases now, I’ll bring younger calves back in on milk if recently weaned and in older calves I treat them according to the symptoms I see, which is usually acidosis.

There are a number of theories why this might be occurring from poor and early weaning to some issues with lush grass on the young, developing rumen. The confusing part seems to be why it occurs quite sporadically.

Grass growth

Last year, I saw several cases in late August when grass began growing rapidly after the drought. There is no doubt in my mind that this condition has something to do with poor weaning and the inability of the young rumen to digest very lush grass.

Lush grass can be low in fibre, high in oils and sugars. This may contribute in some cases to the clinical symptoms of acidosis these calves present with.

So, for farms faced with the issue, I have found rumen buffers for a couple of days to work well. The weaker calves are brought in and some are put back on milk. My own experience is to supplement calves with injectable B12 weekly until they recover.

In the long term, the age of weaning and stepping out weaning seems to help, as does being careful around turnout to very lush pasture during May and July.

With many farmers not seeing issues, this is very much a condition we need to keep monitoring.