World on brink of cow TB breakthrough

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COWS could be bred with natural resistance to Tuberculosis (TB), scientists believe.

The Roslin Institute at Edinburgh University, behind Dolly the cloned ewe, has spent five years searching for the bits of genetic code which allow some cows to stay uninfected when bovine TB hits a herd. And results have been “promising”.

The institute got £500,000 from the British Biotechnology and Biological Sciences Research Council to look into the possibilities, but Roslin team leader Liz Glass revealed yesterday that they had run out of money on the brink of a breakthrough.

They believe that they have identified significant “markers” in the genetic coding of TB-resistant Holstein Friesians.

This means that animals could be selected to breed resistant offspring. But they needed to check their findings.

Professor Glass said: “Promising is a fair summary of the position we are at.”

With the help of Queen’s University, Belfast, the research took place in Northern Ireland, which has a lot of bTB, like much of southern England and Wales.

Samples were taken from cows in infected herds and those which failed TB tests were compared with similar animals which passed.

About 800,000 possible variations in genotype were looked at by the researchers in each case, and the similarities and differences sifted until the likeliest ones had been pinned down.

Prof. Glass added: “It is a complex disease and we are never going to achieve animals which are completely resistant.

“But we could offer a useful additional tool for controlling it, which would have an accumulative effect over the years.”

She said the Holstein findings would not necessarily translate into rules for other breeds but should be a helpful indicator of where to start looking.