Mycoplasma: the unknown disease
Despite indentifying over 80,000 cows on the ICBF database that would meet the EBI criteria for UCD's new demonstration herd, researchers failed to assemble more than 47 due to disease issues encountered in the vast majority of target herds.
While UCD's veterinary advisor, Luke O'Grady had a list of diseases that he wanted source herds to be screened for, it was mycoplasma that ruled out most animals.
"We were determined to avoid herds with Johnes, TB, brucellosis or neospora, but we found that mycoplasma was the biggest problem during the screening process, turning up in at least 50pc of the herds tested," said Mr O'Grady.
"We knew that we could vaccinate for diseases such as leptospirosis, BVD, IBR, rotacorona, RSV and salmonella, but mycoplasma is a bit like Johnes in that it is hard to test for and very difficult to get rid of. There's no vaccine or bulk milk tank test for it, so you can only pick it up through blood samples," he said.
Part of the reason for the lack of awareness about the condition is the variety of symptoms associated with the disease that are often ascribed to other common conditions.
"It results in high culling rates through incurable mastitis, high SCCs, lameness from swollen joints, head-tilt in calves, along with pneumonia-like symptoms and an incessant cough," said Mr O'Grady. It is spread mainly by respiratory transmission, or in milk, and is resistant to many antibiotics.