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Embryo transfer

272. In recent years, the desire to increase rapidly the genetic production index has led to a growing acceptance in the industry of embryo transfer. The procedure is currently undertaken on a relatively small, albeit increasing, scale.

273. The procedure in cattle is mainly carried out by superovulation and non-surgical recovery and involves the transfer of embryos which may have been fertilised in vivo or in vitro . Ovaries may also be collected from dead animals in the abattoir and the ova grown-on and fertilised in the laboratory before transfer. These embryos may be transferred directly or frozen for storage and future use. The procedure for transferring single embryos to carefully selected recipients does not normally cause welfare problems. The continued use of superovulatory drugs can result in subsequent fertility problems.

274. Embryo transfer has now been simplified with the advent of new knowledge which allows frozen embryos to be thawed very quickly and transferred immediately to recipient females. As embryo transfer is carried out at seven days after the onset of oestrus, the technique is more difficult than AI and requires considerable training and experience. Caution must be exercised if this practice is to become widely available in the commercial field, as embryos fertilised in vitro have been implicated in the production of oversize calves. The technique must be carried out using epidural anaesthesia. If a non-veterinarian is administering the epidural, that person must be trained and certified as competent and be a member of an approved bovine embryo team headed by a veterinary surgeon.

275. These procedures are regarded by the industry as part of the normal array of reproductive techniques and welfare concerns are, by and large, addressed by The Bovine Embryo (Collection, Production and Transfer) Regulations 1995 and the Royal College of Veterinary Surgeons' Code of Practice for Embryo Collection and Transfer in Cattle. Invasive techniques of this nature should not be undertaken lightly. In particular, the transfer of embryos which are likely to produce calves of a size or shape which will cause problems at calving, or increased likelihood of caesarean section, is unacceptable. We have recommended previously that the Belgian Blue should not be used on maiden heifers, either as semen or by embryo transfer.

Recommendations

276. The effects of repeated administration of superovulatory drugs and repeated epidural anaesthesia should be kept under review. The industry should maintain records of problems caused and report findings annually to the Agriculture Departments (see also paragraph 285).

277. The requirements of the Bovine Embryo (Collection, Production and Transfer) Regulations 1995 must be carefully adhered to at all times.

278. The recipient mother should be able to carry the chosen embryo to term and to calve normally, without recourse to caesarean section. Caesarean section must not become a routine part of the procedure.

279. A record of caesarean sections resulting from embryo transfer should be maintained and submitted annually to the Agriculture Departments who should monitor the situation.

280. Embryo transfer which does not fulfil these criteria should be regarded as causing unnecessary pain and unnecessary distress.