I will assume for purposes of discussion that we are not dealing with a legal requirement that commits the veterinarian to secrecy, such as a contractual agreement, although even in the this case there is still an ethical question about keeping the contract.
Let us recall some fundamental features of veterinary ethics: veterinarians have distinct and sometimes conflicting moral obligations to animals, owners, society, peers, and self. Plugging these concepts into this case can help us with its resolution.
Clearly the obligations to all parties listed above militate in favor of the veterinarian sharing the information at a meeting. The animals will be better off if the disease is managed, as will animal owners and fellow veterinarians, who can now better deal with the problem. Society will be better off if it does not need to expend resources on the disease in question, and the veterinarian will be acknowledged for his or her role in disease management.
On the other hand, there is clearly something to the owner's concerns. He did pay for the relevant research. I would argue, however, that compensation to the owner should be indirect and come from the veterinarian's disseminating the fact that the owner paid for the research. This ramifies to the farm owner's benefit by virtue of good publicity — he will be seen as a leader in the industry and as producing a quality product. The existence of organizations to promote, for example, the swine industry in general illustrates the point that the competition that obtains across different producers is not a cut-throat Hobbesian war of each against all, where I benefit if and only if you fail, but rather leaves room for innovations that better the image, health status, and public acceptability of products of all producers across the industry.
Thus, the veterinarian, in my view, should report the results but be sure to lavish praise, both in the meeting and to the press, on the owner's progressive management, concern for the industry, and pioneering status in the field.
Such a move may well placate the owner — it would not be good for him to be seen as so mean-spirited as to refuse to help others with disease control. The veterinarian should also point out to him that, in his own management system, he has benefitted from the public dissemination of countless previous innovations. If it does not sway the owner, the veterinarian has little choice but to seek another job, while explaining that she cannot continue to work in a context where innovations that benefit all the parties cited above cannot be shared.