Prominent Australian horseman and Aushorse chairman John Messara says that legalization of artificial insemination for Thoroughbreds would have negative long-term genetic and commercial consequences. Messara's comments on AI were made during his participation as part of an international panel during the Asian Thoroughbred Breeders' Conference in Bangkok. Aushorse is an industry association representing commercial Thoroughbred breeders of Australia.
Messara, who operates Arrowfield Stud, acknowledged it appears there are some to AI, including greater efficiency of stallion use and control of venereal disease. But he added that those benefits are more than outweighed by disadvantages.
"Australia has a Thoroughbred mare population of some 30,000 but only an estimated 11,000 mares are commercially viable, and these are the mares who visited stallions standing at a fee of $A5,000 or more in the 2000 breeding season," said Messara, according to a press release from Aushorse that included his comments. "Imagine if one dominant stallion inseminated 500-plus mares in a season and five or six of his best sons were similarly prolific. This would lead to a significant proportion of our commercial broodmare population being inseminated by one sire line, causing a serious narrowing of the gene pool. This is not a far-fetched scenario. Even without AI, I fear this very thing is happening in Australia right now, due to the resounding success of the Danzig sire line via Danehill and sons of Danehill."
Messara noted there are 46 sons of Danehill at stud in Australia, including three at Arrowfield.
"The fact is that the owners of the commercial broodmare band of, say, 11,000 mares, have used 32 Danzig/Danehill line stallions in the year 2000 and between them they covered one-third of he commercial broodmare band. Thus, due to the success of the Danzig/Danehill sire line, you can see that even on the basis of an average southern hemisphere stallion book of around 100, with the maximum single book last season being 181 mares, we are already in the advanced stages of compromising the diversity of our gene pool in Australia, simply through market forces, despite the limitation imposed by a regime of natural service."
Messara said that trend would accelerate with AI.
"The integrity of our gene pool would be seriously put at risk if AI were introduced without a restriction on numbers per stallion with a serious loss of hybrid vigor, and other negative effects which may not be exposed for a number of years," Messara said
He added, however, that such limitations would be a restraint of trade and potentially open to a legal challenge, unless it could be firmly proved that such a restriction was reasonable and that the purpose of such a restriction was to protect genetic integrity of the Thoroughbred breed.
Messara said the most appropriate approach was to devote any further resources to developing the defensible reasons for maintaining the ban and/or properly investigating the case for restricting the size of stallion books should the ban ever be successfully challenged.
"Furthermore, the horse industry is global, and if restrictions on numbers per stallion were not capable of being legally enforced in any one member country of the International Stud Book Committee (ISBC) then I would suggest that lifting the AI ban would not be contemplated by any of the others."
Also, Messara said artificial insemination would also lead to a few select stallions inseminating a disproportionately large number of mares each breeding season, forcing some smaller operations to cease stallion activities and also leading to less demand for new stallions.
"Perhaps horses like Sir Tristram and Danzig may never have been given a chance had AI been in place at the time. This is not in the best interests of the breed, or the industry. There would be a devaluation of certain industry assets and could lead to job losses on our farms. But while it appears on the surface to be easy to purchase a semen straw and inseminate a mare at home, in practice it is not as simple as that, as other equine breeds have discovered.
"Evidence indicates there is a wide disparity in fertility rates using fresh, frozen or cooled semen and I understand that pregnancy rates from cooled or frozen semen lag behind those from fresh semen," Messara continued. "Among the mysteries to be solved is the question of why semen from one stallion will withstand freezing while semen from another will be destroyed. With AI, broodmare owners naturally would have a higher expectation of conception but AI technology is still fraught with difficulties. I accept that inseminating mares artificially with fresh semen may create greater efficiency in stallion use, better management of older and less fertile stallions, better fertility and more cost effective stud operations. But Aushorse holds the strong view that lifting the ISBC ban on AI without a legally enforceable and irrevocable limit on numbers per stallion is simply too great a risk for us to take."