On 16 March 2017, the European Medicines Agency EMA) concluded its assessment of the benefit-risk balance of veterinary medicines containing zinc oxide that are administered orally to pigs. The assessment, which was conducted by the EMA expert group, the Committee for Medicinal Products for Veterinary Use (CVMP), concluded that overall the benefit-risk balance for the products concerned is negative, as the benefits of zinc oxide for the prevention of diarrhoea in pigs do not outweigh the risks for the environment. The CVMP acknowledged that there is also a risk of co-selection for antimicrobial resistance associated with the use of zinc oxide. However, at the present time, that risk is not quantifiable.
The CVMP has recommended to the EU Commission that all existing marketing authorisations for products concerned by this procedure be withdrawn in a phased basis, to allow farmers and other stakeholders to adapt to the new situation. A final decision in respect of the CVMP recommendation was taken on 19 June 2017, following a meeting between the European Commission and Member State governments in Brussels. That decision was to withdraw the products concerned throughout the European Union, over a maximum of 5 years, i.e. before June 2022.
Serial Or Batch Number And Expiry Date:
In Ireland, the following products containing zinc oxide have been authorised by the HPRA for use in pigs:
- Gutal premix, VPA 10782/16/1 (Huvepharma Ltd)
- Pigzin premix, VPA 10443/1/1 (DSM Nutritional Products Ltd)
- Zincotec premix, VPA 10446/1/1 (Provimi Ltd)
Problem Or Issue:
Zinc is relatively poorly absorbed and is eliminated in the faeces. When excreted by pigs, it is presented to the environment in pig slurry. Zinc is very toxic to aquatic organisms and can cause toxic effects in both aquatic and terrestrial animals. Zinc is persistent in soils and may accumulate in sediments. Toxicity will depend on environmental conditions, soil types and amount added to the environment through use in pigs.
Although only authorised for the control of diarrhoea in piglets by the HPRA since 2013, zinc oxide has traditionally been favoured by veterinary practitioners as an alternative to antibiotics.
The premix is normally incorporated into finished piglet feed to give a dosage of 2300 to 2500 mg elemental zinc /kg bodyweight and fed for up to 14 days during the high risk weaning period.
The products concerned are extensively used, with most animals receiving the product during the period post-weaning.
Actions To Be Taken:
Pending the withdrawal of the marketing authorisations for the products concerned, in accordance with the decision of the EU, medicines containing zinc oxide remain authorised and veterinary practitioners can continue to prescribe these products until June 2022. For the control of diarrhoea in piglets there are a range of potential therapeutics and vaccines authorised for use. Users should discuss their needs with their veterinary practitioners, who will also advise on other disease control measures including biosecurity, husbandry and nutrition.
As use of the products continues, veterinary practitioners and farmers are advised to closely follow the existing recommendations regarding the environment and medicines containing zinc oxide.
In particular, it is currently recommended that manure from treated pigs should not be spread on vulnerable soils, identified as free draining, acidic (pH < 6), sandy soils. Manure from treated pigs should be diluted with those of untreated animals or sows, so that the amount of treated piglet manure is as low as possible and never exceeding 40% when manure from weaned piglets and sows is stored together. Manure containing zinc should not be spread on the same area of land in successive years to avoid accumulation of zinc which may cause adverse effects in the environment. When spreading manure from treated animals, the minimum buffer distance from water courses is at least 3 metres.