Emerging ‘summer scour’ syndrome causing dairy calf deaths

An emerging syndrome has been noted across Europe – including in Ireland and the UK – which is causing the deaths of dairy calves at pasture, according to the Department of Agriculture, Food and the Marine.

The syndrome, according to the authority, is known as “summer scour of dairy calves at pasture”, among other terms.

The department has assured that, overall, the disease prevalence and impact has been low, except on a small number of severely affected farms and, even on those, deaths are not common.

The disease causes scour in calves, usually affecting animals at grass about a month after weaning; the defining feature is that there is no evidence of the typical causes of such a scour.

Regional veterinary labs received reports of the disease last September following a flush of grass after the severe summer drought ended.

“Some thought has been given to whether it is associated with poor ruminal development, and there has been debate about other dietary influences, but these suggestions are largely speculative. So far no one factor seems to cover all cases,” the department said in a statement.

It was noted that the syndrome could appear one year before disappearing and not returning the following year, with no change in feeding routines.

“It is not clear whether this syndrome is infectious or dietary in origin, but there appears to be an epidemiological association with early weaning and early grazing on lush monoculture pastures,” the department added.

So far no infectious agent has been linked with it, but it is important that coccidiosis, parasitic gastroenteritis, copper deficiency etc. are well controlled before suspecting that this syndrome is involved.

At present, this condition is largely diagnosed by a combination of the history, the post mortem findings, and careful exclusion of conventional causes.

An informal trans-boundary research group across some European countries, including Ireland, has developed a case definition and is actively seeking notifications of outbreaks to investigate the disease.

The efforts to better define the syndrome and develop standardised and evidence-based advice is still in the early stages.

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