Many co-ops have experienced a "very substantial reduction" in veterinary medicine sales since new regulations came into effect.
This is according to the Irish Co-operative Organisation Society (ICOS).
From December 1, 2025, all antiparasitic medicines for food producing animals are no longer available to purchase without first having a veterinary prescription.
ICOS livestock and environmental services executive, Ray Doyle said since the introduction of the new veterinary medicine regulations, cooperatives across the country have experienced a "significant change" in how veterinary medicines are supplied to farmers.
"The transition to electronic prescribing has generally worked well and systems such as VetPal have proven efficient, with prescriptions being processed quickly and reliably," Doyle told Agriland.
"However, while ICOS fully supports the objective of promoting responsible medicine use and reducing the risk of antimicrobial and antiparasitic resistance, the commercial impact on cooperative retailers has been significant.
"Many co-ops have experienced a very substantial reduction in veterinary medicine sales since the regulations came into effect, although this has been influenced to some extent by farmers purchasing stock ahead of the December 1 implementation date."
Doyle highlighted that increased costs associated with the prescribing process, combined with reduced sales volumes, have "significantly eroded" retail margins.
"Without changes to the current system, there is a real and genuine concern that many cooperative stores will no longer be in a position to continue retailing veterinary medicines over the coming years," Doyle said.
"ICOS believes there is an opportunity to strengthen Ireland's animal health strategy by improving access to vaccines.
"While antiparasitic treatments should continue to be used carefully to help combat resistance, greater emphasis should be placed on disease prevention through vaccination."
Doyle said that vaccines should be made available to farmers through the same prescribing protocol that now exists for antiparasitic medicines.
"This would support higher vaccine uptake," he continued.
"This in turn would improve herd and flock health, help reduce disease pressures and ensure farmers continue to benefit from the convenience, competition and advice provided through their local cooperative network."
ICOS said it is "committed to working constructively" with the Department of Agriculture, Food and the Marine and industry stakeholders to ensure the regulations "continue to meet animal health objectives".
However, "there must also be fairness and competitiveness in the system for farmers and merchants", Doyle added.