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stant-sheep-the-focus-of-phd-thesis-13-05-2008>

Disease resistant sheep the focus of PhD thesis

The ability to breed sheep resistant to paratuberculosis, a chronic
disease which leads to production loss, is the goal of PhD student Rao
Dukkipati. The disease, while not fatal, makes sheep lose weight and
produce less wool.

Studies estimate around 70 per cent of New Zealand’s 40 million sheep are
infected with the disease, costing the industry about $10 million a year.

Dr Dukkipati, who graduated yesterday, identified genetic markers for
immune responses to paratuberculosis vaccination in 900 merino sheep in
Australia.

Six genotypes and four alleles at six marker loci were found to be either
“probably” or “most likely” to be associated with immune responses to
vaccination, he says.

“The presence of a particular marker genotype or allele may lead to a
lower or higher response to the vaccine. It is likely that they will
behave similarly to the natural disease.”

Identifying the markers could lead to the selective breeding of disease
resistant animals.

“These animals would be bred exclusively to improve genetic resistance to
paratuberculosis.”

Dr Dukkipati came to Massey from India in 2002 and completed his PhD at
the Insitute of Veterinary, Animal and Biological Sciences last year. His
wife, Kavitha Kongara, is also working on her doctoral thesis in clinical
veterinary science at Massey.

The couple have become New Zealand citizens and Dr Dukkapati is now
employed at the institute as a researcher.

“We were hoping to graduate at the same time, however she will defend her
thesis later this month and graduate at the next ceremony,” he says.

“I’m working now on a sub-vaccine which will work against
paratuberculosis. At the moment there are a number of commercial vaccines,
but none protect the animals completely.”

Created: 13/05/2008 | Last updated: 13/05/2008