A new inherited disease that causes ptosis, intellectual disability, retarded growth and mortality (PIRM) in Ayrshire calves has been discovered.
Of 129 tested Ayrshire artificially inseminated bulls recently used in Finland, 17% carried the mutation.
The mutation may be connected to Ayrshire haplotype 1, which is associated with reduced fertility and has a carrier frequency of 26.1% in the North American Ayrshire population. The phenotype has been defined as PIRM syndrome according to its typical features, which include intellectual disability and retarded growth.
However, the most noticeable symptom of affected calves is the ptosis. The large upper eye lid gives a characteristic sleepy appearance in affected animals.
Some affected calves also suffered from feeding problems, minor structural changes of the head and muscular hypotonia.
PhD student Heli Venhoranta, said: “The results of this study can be utilised in bovine breeding programs.
“With the successful prevention of PIRM syndrome, the animal welfare can be increased and at the same time the financial losses for farmers and breeding companies can be reduced.”
In humans, mutations in UBE3B gene are associated with Kaufman oculocerebrofacial syndrome with similar pathological findings as in PIRM syndrome.
Furthermore, mice engineered to lack UBE3B expression were reported having increased lethality.
The study was published in full in the BMC Genomics journal.