Type 2 ostertagiasis – Is there an impact and are we missing it?

We have had a few submissions, case reports and post-mortem examinations recently regarding scour in groups of older cattle that grazed last year.

In these cases we have either suspected or confirmed type 2 ostertagiasis, based on the history and clinical signs, gross pathology at post-mortem and clinical pathology findings of high pepsinogen and low albumin levels with or without a patent worm egg count.

The disease is caused by the maturation and emergence of L4/L5 larvae that have been inhibited over the winter in the gastric glands in the abomasal mucosa. If maturation and emergence is synchronous then severe clinical disease can be seen. If  emergence occurs over a longer period of time then the disease may be less severe or not evident at all. However, this presentation will still result in significant pasture contamination for the forthcoming season.

Clinical signs can include scour of varying severity, significant weight loss and, in chronic cases, oedema associated with hypoproteinaemia. The severe cases, group outbreaks and deaths are easy to identify, but the milder cases may go unnoticed with any scour being thought to be due to a diet change and lush spring grass. The abomasal mucosal damage can be significant in surviving animals and therefore chronic ill thrift can be a feature. Monitoring body condition and weight gains are particularly important tools.

It is worthwhile considering the risk of type 2 ostertagiasis in grazing cattle just now so that wormer strategies and grazing management in the autumn can be reviewed.

Posted by SRUC Veterinary Services on 06/06/2022