Detective work begins to find cause of dwarfism in Scottish beef herds

Beef farmers are being asked to provide information that may help to solve a disease in cattle that has baffled the veterinary profession for several decades.

No-one knows how many calves are born suffering from dwarfism. The short legs of the severely affected cases are easily recognised, but there can be a range in severity, with some calves being only very slightly affected.

The worst-affected calves may not be able to stand or suck and need to be put down, but for those that can get around and feed there is a dilemma for the farmer. Will they survive to produce a saleable carcase or should they too be culled to cut the losses?

It is mostly, but not uniquely, found in beef herds, with a few cases coming from the dairy sector.

George Caldow, regional veterinary adviser with the Scottish Agricultural College based in St Boswells, said yesterday it was time that the agricultural industry tackled the disease which has been around for the past 30 or so years.

"We need to find out more about it so that we are better equipped to deal with it," he stated, comparing the lack of action over dwarfism with the positive and quick action taken last year when bleeding calf syndrome emerged as a problem.

So far what is known about dwarfism is that it looks very similar, but not identical, to livestock that suffer from manganese deficiency, but Scottish cases appear to have normal levels of manganese in their body.

The condition has been linked to the feeding of silage during the pregnancy of the cow and one control method has been limiting the amount of silage fed during pregnancy to less than 70 per cent of the dry matter by diluting the ration with straw.

"Initially we saw it exclusively where cattle had access to grass silage that was made in the pit and we didn't find it where cows were fed on big bale silage but that point of differentiation is no longer true."

Looking for a solution, he commented yesterday: "It does seem that the problem is always greater in the year after better quality silage has been made, and it has been suggested that in those years the silage contains a compound that could be locking up an essential factor for normal bone development."

Work was carried out in Ireland last year following an increase in numbers of calves affected by the problem. The researchers there suggested that it might be caused by a fungal infection but Caldow thought this didn't quite fit with the Scottish experience where good, rather than spoiled silage has usually been fed.