Last autumn, I was called to look at a mob of 100 rising 1 year old dairy calves that had recently arrived on farm. They were scouring, in poor condition and one animal had died. They had been drenched on arrival and again ten days before my visit but were still scouring and losing condition.

They were a variable mob from 140-180kg, some Jerseys, some Friesians and they were an average Body condition score of 3. They were on grass with no supplementary feed and they were showing signs of Ryegrass staggers so moving them into the race was not so easy!

At least half of the mob was scouring mildly and some showed signs of more severe diarrhoea. When I examined the worst looking calves, I found no further clinical signs of disease (normal temperatures etc.), so I took some blood and faecal samples sent them to the lab for testing.

The blood samples showed increased white blood cells, showing a bacterial infection, low red blood cells (anaemia) and low protein – probably related to loss through the gut in this case.
The faecal samples showed no parasite eggs, low numbers of coccidian oocysts, and no Salmonella growth but did return a positive result for Yersinia.

So what is Yersinia?

It is a bacterium that causes scouring and intestinal damage. It spreads through infectious faeces on the grass and can often be found in wet soil and water, and also is often in the intestine without causing disease. Some farmers find that the same paddocks seem to cause disease year after year. Stress factors such as a feed pinch, being transported or poor weather all increase the chances of clinical signs developing, but yersiniosis can develop in well fed animals too.
Treatment consists of long acting oxytetracycline antibiotics, but management changes such as deceasing stocking rate, putting calves into drier paddocks and supplementary feeding will reduce the effect on sick animals and reduce infection rate.
Often we don’t get called to these cases until much of the mob is affected but earlier intervention with the right treatment gets everyone back on track quicker. Give us a call if you have any concerns!