‘No evidence’ imported frozen semen cause of mycoplasma outbreak
MPI has confirmed no evidence that of resistance to mycoplasma in imports of bovine semen.
World Wide Sires – marketing arm of the largest dairy farmer owned cooperative in the world Select Sires/Accelerated Genetics – reinforce all bulls and semen free of the disease.
The New Zealand arm of the largest dairy farmer owned cooperative in the world – and one of the globe’s major semen companies – is pleased MPI has confirmed there is no evidence that resistance has developed to mycoplasma in imported bovine semen*.
World Wide Sires New Zealand General Manager, Hank Lina, said the company – along with other importers of bovine semen – have been working with MPI to isolate and identify the source of the outbreak.
“We sell more than 19m straws of semen to 80 countries around the world and, over several decades, have developed semen production and processing procedures which are amongst the most rigorous in the world. They need to be because farmer confidence is at stake and we would never jeopardise that trust – they have to know that our product is safe.
“MPI’s validation that imported semen was not the cause of the mycoplasma outbreak is bitter sweet – we’re naturally delighted to have this confirmation of our standards and systems but our hearts go out to the Van Leeuwen family who are living through a farmer’s worst nightmare.”
Hank Lina said Select Sires initiated research on fresh semen programmes nearly two decades ago.
“At the time, we were frustrated at the variability, which existed among laboratories, in their ability to grow and culture mycoplasma and the long interval necessary for results when it was assessed by culture.
“Around seven years ago we were fortunate to come into contact with Kristina McDonald, a microbiologist of some renown, who wanted to make the identification of M.bovis the central theme of her PhD because that is one of the more pathogenic strains of microplasma. Select Sires sponsored that research.
“Dr McDonald’s PhD made use of modern PCR based techniques to detect mycoplasma bovis in semen. She developed efficient methods for growth, culture, DNA extraction, and PCR based detection.
“No evidence of mycroplasma bovis was found in any of Select Sires’ 1700 bull team either during the research programme, or since.”
“The extender we use for frozen semen is made from homogenized, pasteurised whole milk and glycerol. Antibiotics including Gentamicin, Tylosin, Lincomycin, and Spectinomycin provide a secondary line of defense against seminal contamination as well as primary action against mycoplasma, ureaplasma, and Haemophilus somnus.
Hank Lina commended MPI on the depth of the investigation they were undertaking to identify and isolate the outbreak.
“Along with other semen companies, we were required to provide batch numbers and details of all bovine semen imported to New Zealand and potentially supplied to the Leeuwen group. No stone was left unturned meaning their eventual validation was well received – but the investigation also provided insight to the disciplines and expertise which exist in this country to protect our industry from incursions of disease which have affected so many other countries around the world,” Hank Lina said.
Email from Angela Snell, Senior Advisor for MPI’s Animal Imports Team (dated 3 August) -
“the Animal Imports team has reassessed the risk of Mycoplasma bovis entry in imported semen. The rapid spread of this organism to many countries during the 1970s to 1990s is considered to have been due to the movement of infected animals, and there has been little recent research on other potential routes of transmission. There is a strong international view that semen can become contaminated if infection is present on the bull’s reproductive tract at the time of collection. However, when standard collection hygiene is practised, reports indicate that bacteria are not observed in semen. While there are several references in the literature that show that M. bovis can be demonstrated in semen and that it can remain viable when frozen for long period, there is little scientific information suggesting this as a route of transmission to cows.
Our trading partners export semen from
that have long standing practices, operating under strict standards, to control for all sources of contamination. Various combinations of antibiotics have been demonstrated to kill Mycoplasma contaminants in semen. These combinations are recommended by the World Organisation for Animal Health (OIE), and are reflected in the regulatory systems of our trading partners. Alternate antibiotic combinations are permitted when they are demonstrated to achieve equivalent control. Mycoplasmas are notoriously difficult to treat with antibiotics, and antibiotic resistance must be considered; however, New Zealand has been importing semen for many decades without incident and at this time there is no evidence that resistance has developed or that standard hygiene practices have been breached.
There are no biosecurity controls in place on imported semen or embryos and importation continues under the existing requirements of the negotiated veterinary certificates.”