Problem Or Issue:
The use of flukicides in dairy cows may, if withdrawal periods are not observed, result in detection of drug residues in milk and the milk being rejected as unfit for consumption. Currently, there are seven active substances that are contained in veterinary medicines that may be used to treat fluke, but only two of these substances (i.e. albendazole and oxyclosanide) are for use in lactating dairy cows producing milk for human consumption. A list of products containing these substances, as the sole active ingredient, and authorised for use in dairy cows is attached as Appendix 1. Note that there are also veterinary medicines which contain these substances but in combination with others. Use of such combination products in dairy cows is dependent on whether the products have been authorised for such use by the IMB, following the conduct of residue studies and confirmation that residues of all substances are permitted in the European Union.
Since 2012, approved residue limits (so-called ‘maximum residue limits’ (MRLs) have been established in the European Union for milk for four of the five remaining substances (i.e. clorsulon, closantel, nitroxinil and triclabendazole). A list of products containing these substances, as well as products containing rafoxanide, as the sole active ingredient is attached as Appendix 2. Even though an MRL has been established, for most veterinary flukicides containing these substances, the advice of the IMB remains as was – follow the directions for use stated on the product labelling and Summary of Product Characteristics (SPC; available elsewhere on the website). In the case of pregnant animals and maiden heifers, the following table outlines the precise position for use:
| Substance | Species | Route of administration | Use in pregnant maiden animals |
| Clorsulon | Cattle | Subcutaneous | Not relevant as used in combination products only |
| Closantel | Cattle | Oral | Do not use during the second half of pregnancy |
| Closantel | Cattle | Subcutaneous | Do not use during the last trimester of pregnancy |
| Closantel | Cattle | Pour-on | Not relevant as used in combination products only |
| Closantel | Sheep | Subcutaneous | Do not use within one year prior to the first lambing |
| Closantel | Sheep | Oral | Do not use within one year prior to the first lambing |
| Nitroxynil | Cattle | Subcutaneous | Do not use during the last trimester of pregnancy |
| Nitroxynil | Sheep | Subcutaneous | Do not use within one year prior to the first lambing |
| Nitroxynil | Goats | Subcutaneous | Do not use within one year prior to the first kidding |
| Rafoxanide | Cattle | Oral | Do not use during the last trimester of pregnancy |
| Rafoxanide | Sheep | Oral | Do not use within one year prior to the first lambing |
| Triclabendazole[1] | Cattle | Oral | Do not use during the last trimester of pregnancy |
| Triclabendazole | Sheep | Oral | Do not use within one year prior to the first lambing |
| Triclabendazole | Goat | Oral | Do not use within one year prior to the first kidding |
| Triclabendazole | Cattle | Pour-on | Do not use in cattle of any age intended to produce milk for human consumption |
[1] Excludes Fasinex 240 (Novartis), Endofluke 100mg/ml Oral Suspension and Fasifree 10% w/v Oral Suspension (Cross Vetpharm Group Ltd.).
Fasinex 240, VPA 10825/004/002, which contains triclabendazole, has been authorised by the IMB in 2012 for use in the treatment of mature, immature and early immature fluke in dry cows (subject to a withdrawal period of 35 days plus 48 hours).
On 21 and 26 November 2013, Endofluke 100 mg/ml Oral Suspension, VPA 10960/046/001 and Fasifree 10% w/v Oral Suspension, VPA 10960/043/001 respectively, both also containing triclabendazole were authorised for use in the treatment of mature, immature and early immature fluke in dry cows (subject to a withdrawal period of 45 days plus 48 hours for both products).
The position of other veterinary medicines may change should new residue data be submitted that would allow the
IMB to authorised an appropriate withdrawal period. In such an event, the
IMB will upload the new SPC to the list of authorised veterinary medicines on the website and the labelling of the product is amended. New stock will bear the updated labelling from the date of the new production run.
A composite chart to assist users to identify which products are most suitable for use in pregnant and lactating dairy animals has been developed between the IMB and the Animal Health industry to help users identify which product types can be used. The chart can be viewed
here.