Zinc oxide withdrawal and post-weaning diarrhoea: a priority innovation challenge
What changed and what did not
The EMA review concerned veterinary medicinal products containing zinc oxide administered orally to food-producing species. The agency describes a typical medicinal use in piglets as 100 mg/kg bodyweight/day for 14 days, equivalent to 2,500 ppm zinc in feed. It concluded that the benefit–risk balance was negative because the benefit in preventing diarrhoea did not outweigh environmental risk; it also acknowledged a potential co-selection risk for antimicrobial resistance that was not quantifiable at the time.
This is an important precision point for client communications. The change should not be described as a ban on zinc as a nutritional trace element, nor as evidence that every post-weaning diet must perform poorly. It means that pharmacological veterinary ZnO is no longer the routine post-weaning safeguard it once was in EU pig production. Consequently, farms, feed businesses, veterinarians and technology suppliers need prevention systems that are validated in the conditions in which they will be used.
Why PWD is an innovation problem
PWD is multifactorial. It commonly occurs during the first 14 days after weaning, when piglets experience dietary change, altered feed intake, stress and changes in intestinal function and immunity. Enterotoxigenic Escherichia coli (ETEC), including F4/K88-associated disease, is a major cause, but a farm’s risk profile also depends on pathogen exposure, hygiene, weaning management, diet, water, temperature, mixing, density, batch quality and other herd-specific factors.
Teagasc’s Irish ZincO project states that high-level ZnO had been used to control diarrhoea in early-weaned pigs and that removing it can be associated with mortality and growth delays. Its purpose is to investigate the pig microbiome, resistome and immune response under commercial conditions, and to develop effective approaches that enable viable removal. Teagasc’s research update also reports variability between batches, which is a strong reason to treat PWD control as a data-led, farm-specific challenge rather than an additive-selection exercise.
| The incorrect simplification | The more defensible position |
| “Removing ZnO causes diarrhoea.” | Withdrawal removes a historically effective tool; PWD outcomes depend on pathogen, piglet, nutritional, environmental and management factors. |
| “Replace ZnO with a single additive.” | No universal substitute should be assumed. Interventions require herd-specific veterinary/nutritional assessment and evidence under commercial conditions. |
| “Lower antibiotic use is always the target.” | Responsible antimicrobial stewardship must protect health and welfare; diagnosis, prevention and appropriate treatment protocols remain essential. |
| `“Every diet trial is R&D.” | A standard ration comparison is ordinarily routine. R&D requires a stated technical uncertainty, systematic experimental work and an advance beyond readily available knowledge. |
Practical response: build a ZnO-free resilience system
A resilient post-weaning system begins before weaning. It considers sow and piglet quality, colostrum and early-life management, pre-weaning feed familiarity, batch structure, water availability and hygiene. It then integrates a digestibility-appropriate starter strategy, room and pen environment, pathogen and diarrhoea surveillance, staff response protocols, and post-event review. The exact mix should be designed with veterinary and nutrition advisers, using the farm’s own disease and performance history.
This is a promising area for properly designed R&D where a business cannot rely on an established answer. Examples may include developing and validating a diet-response model that accounts for ingredient variability and farm-specific ETEC risk; testing a multi-sensor early-warning system for feed, water, faecal-score and climate changes; or creating cleaning-verification and batch-flow controls that reduce recurrent PWD risk without increasing antimicrobial exposure. The work must be systematic and must test an unresolved scientific or technological question—not merely purchase an existing feed additive or equipment package.
InnoFund perspective. The ZnO transition creates a case for joined-up innovation: biological robustness, gut-health management, feed science, environmental control, diagnostics, data and staff workflow must be tested as one operating system.
When Ireland’s R&D Corporation Tax Credit may apply
Ireland’s R&D Corporation Tax Credit is relief available to innovative agricultural businesses within the charge to Irish tax that undertake qualifying activity.
Potentially eligible entities include:
- Private Limited Companies (LTDs)
- Designated Activity Companies (DACs), including DACs limited by guarantee
- Companies Limited by Guarantee (CLGs)
- Public Limited Companies (PLCs)
- Unlimited companies: ULCs, PUCs and PULCs
- Investment companies
- Societas Europaea (SEs) registered or tax-resident in Ireland
- Foreign-incorporated companies that are Irish tax-resident
- Non-resident companies carrying on a trade through an Irish branch or permanent establishment, where the relevant expenditure and activities fall within the Irish Corporation Tax charge
- Other incorporated bodies, potentially including certain co-operative or registered societies, if they constitute a body corporate and are actually within the Corporation Tax charge
Entities that are normally excluded are:
- Sole traders, because they pay Income Tax rather than Corporation Tax
- Ordinary partnerships and most limited partnerships
- Individuals and unincorporated associations
- Charities, pension schemes, investment funds or other bodies whose relevant income is exempt from Corporation Tax, although their precise position depends on their legal form and tax treatment
Importantly, merely paying or registering for Corporation Tax is insufficient. The entity must also:
- Conduct qualifying scientific or technological R&D in Ireland, the EEA or UK
- Seek an advancement in science or technology
- Address scientific or technological uncertainty through systematic investigation or experimentation
- Incur qualifying expenditure that is not deductible in another country
- Make its claim through the CT1 within 12 months of the relevant accounting-period end
- Comply with the 90-day pre-filing notification where it is a first-time claimant or has not claimed during the preceding three years
Revenue’s current manual requires the activity to be systematic, investigative or experimental; in a field of science or technology; directed to scientific or technological advancement; and intended to resolve scientific or technological uncertainty. Revenue’s prescribed fields include Agricultural Science, including agriculture and animal husbandry, with veterinary medicine separately listed.
Common areas of qualifying R&D activities
- Precision feeding and feed efficiency
Develop adaptive phase-feeding systems, alternative ingredients, enzyme combinations and amino-acid strategies that improve FCR while reducing cost and nutrient excretion. - Early disease detection
Combine drinking, feeding, movement, sound, temperature and camera data to identify disease before conventional clinical signs appear. - Biosecurity and pathogen control
Develop improved cleaning validation, pathogen-exclusion systems, vaccination strategies and risk-prediction tools suitable for commercial Irish units. - Tail-biting prevention and welfare
Test integrated solutions involving enrichment, genetics, stocking density, feeder access, ventilation and behavioural monitoring. - Intelligent ventilation and climate control
Develop pen-level airflow and climate controls that balance temperature, humidity, ammonia, dust, animal welfare and energy consumption. - Antimicrobial-use reduction
Create diagnostics and decision-support systems that enable earlier, more targeted treatment while maintaining health and welfare outcomes. - Slurry treatment and ammonia reduction
Develop separation, acidification, storage, nutrient-recovery and low-emission application systems that are safe and commercially viable. - Piglet survival and early-life performance
Investigate maternal nutrition, farrowing environments, colostrum management, neonatal monitoring and interventions that reduce mortality and weight variation. - Genetics for robustness and lifetime efficiency
Develop phenotypes and breeding methods for disease resilience, feed efficiency, survival, maternal ability, welfare and reduced environmental impact. - Labour-saving automation and integrated data
Develop reliable automated weighing, drafting, cleaning and monitoring systems, supported by a shared data platform connecting feed, health, housing and carcass results.
| Question | What stronger evidence looks like | What does not qualify by itself |
| Is there a technical uncertainty? | The business can explain what a competent professional could not readily resolve using publicly available knowledge or routine practice. | Commercial uncertainty |
| Is the work systematic? | A protocol, hypothesis, comparison, defined endpoints, documented changes and conclusions. | Unstructured trial-and-error |
| Is an advance sought? | A new or improved capability in nutrition, engineering, health monitoring, data or environmental control. | Buying a proven feed sensor, ventilation system, software product or feed formulation by themselves. |
| Can the costs be evidenced? | Contemporaneous project records, cost allocation, payroll/time evidence, invoices, trial materials and results. |
Costs Claimable
For accounting periods with a specified return date on or after 23 September 2027—generally, accounting periods ending 31 December 2026 or later—the credit is 35% of allowable expenditure.
Qualifying revenue expenditure is limited to statutory categories of expenditure incurred wholly and exclusively in carrying on qualifying R&D (as documented in the image to the right).
Revenue’s manual permits just-and-reasonable apportionment for plant and machinery used for both qualifying R&D and non-R&D production.
What if I have already received a grant?
A project that is grant-funded can still be claimed under the R&D Scheme. Where a project is grant-funded, only the self-funded portion of the grant is in scope to be claimed as an eligible R&D cost.
Companies intending to claim for the first time, or after a three-accounting-period gap, may be subject to pre-filing notification. Where it applies, Revenue says the prescribed notification must be submitted at least 90 days before the claim is made.
In the next post we will cover ‘Where credible R&D may rise in the pig sector‘ , ‘Building credible on-farm innovation‘, ‘Collaboration and funding routes‘, and ‘From project activity to innovation value‘.