Cattle disease here, deal with it
Given the poor success rate of eradicating invasions of exotic organisms in New Zealand, it is highly unlikely that Mycoplasma bovis will be wiped out or even contained.
Are we in danger of overreacting to the discovery in July last year of the cattle disease Mycoplasma bovis?
The bacterial disease causes a range of serious conditions including mastitis pneumonia, arthritis and late-term abortions. It does not infect humans and presents no food safety risk. Until the discovery, only two countries, New Zealand and Norway, were free of the disease. Other countries have learned to manage it in the same way that other animal disorders are managed.
The disease seems to have been contained to Hawke’s Bay and South Island dairy farms, where it was first discovered. Other farms which may have received cattle from the infected farms have been put on movement notice by the Ministry for Primary Industries.
The discovery sent ripples of fear and uncertainty through farming communities with cattle sections of A & P shows being cancelled and buyers at stock sales unwilling to bid on cattle from regions where the disease exists. No one really knows how long it has been here but it could probably only have come in through imported cattle or live cattle tissue.
Our border controls are designed to prevent these invasions but a close examination of some of these controls is cause for alarm. The Ministry for Primary Industries guidance document for importing semen and embryos, dated August 10, 2017, gives strict rules for some importations but almost none for others.
The rules state that donors can only come from a herd that is free from bovine tuberculosis in accordance with the veterinary authority of the exporting country.
However, the book also states that the donors can come from herd that has ‘‘never recorded a positive test for Mycoplasma bovis’’. If the herd has never been tested there is no positive or negative test and there are suggestions that this loophole could have been exploited to avoid the significant cost of testing at least eight years ago.
Antibiotic treatment of cattle tissue is rarely completely successful.
A further cause for concern is the abysmal enforcement of the National Animal Identification and Tracing programme (NAIT) by the Ministry for Primary Industries. This requires all cattle and deer to be fitted with an electronic ear tag and every movement of stock on and off farms must be logged on a central database. At the outset of the discovery it was clear that many farmers had not complied with those requirements. As a consequence no one knew with any certainty where potentially infected cattle had gone. They still don’t.
The disease could have been here for many years but only developed into an epidemic when dairy cows were housed closely together for several weeks in South Island winter barns. Under those conditions the disease could have spread rapidly as the human flu virus did in the trenches of World War I.
Given the poor success rate of eradicating invasions of exotic organisms in New Zealand, it is highly unlikely that Mycoplasma bovis will be wiped out or even contained. We still have rabbits, deer, possums and Tb, and we failed to eliminate the more recent invasions of varroa bee mite and didymo.
Waiting in the wings of this unhappy saga is the dreadful possibility that one day we might be faced with a genuinely serious invasion like foot and mouth disease. Given the performance of MPI to date, there are serious questions to be asked about our border security and the advisability of ever setting up the organisation in the first place. In spite of its hard work and dedication, MPI appears to be understaffed, underfunded and overloaded with far too many heavy responsibilities for a single organisation. If so, that leaves us exposed to too many unmanageable risks.
Culling 22,000 cows from the national herd of about 6.7 million may not seem to be a huge threat to the national economy but it will hit North Otago, South Canterbury and Hawke’s Bay rural communities very hard.
It will cost taxpayers about $38 million in compensation, Fonterra has contributed a further $11m to the project, and it will take at least three years for dairy herd numbers to recover. That does not take into account the distress of dairy farmers, who have done nothing wrong, but who must send their cows to slaughter.
Perhaps it would be better in the long run to accept that Mycoplasma bovis is here to stay, that it must be managed, and that there is no need to cull productive dairy cows or put everyone to so much expense and stress.