The Generative Brain

Real Decreto 21/2013, Spanish national programme of genetic selection for TSE resistance in sheep

Real Decreto 21/2013 of 18 January 2013 is the Spanish royal decree that runs the national programme for breeding sheep that resist transmissible spongiform encephalopathies (TSEs), above all classical scrapie. It works through the sheep prion protein gene, PRNP: animals are typed at codons 136, 154 and 171, the ARR allele is favoured, and animals carrying VRQ, the allele linked to the highest susceptibility, are kept out of breeding in participating flocks. Taking part is voluntary for any sheep holding, but once a flock joins, all breeding rams must be genotyped and VRQ carriers must go to slaughter. Results are held in ARIES, a ministry database, and flocks can be officially recognised at three levels of resistance. The decree replaced Real Decreto 1312/2005, which had made participation compulsory for pedigree flocks and carried subsidy rules. Its original article 14 named the Laboratorio Central de Veterinaria at Algete as national reference laboratory for sheep PRNP analysis. From 1 October 2026 Real Decreto 682/2026 rewrote article 14 to point to the ministerial designation order, and that order, Orden PJC/1015/2026, again names Algete for PRNP analysis in this programme. The decree concerns sheep only and plays no part in human CJD testing or care. Information only, not legal, medical or veterinary advice.

Key facts

  • The decree is dated 18 January 2013, was published in BOE no. 33 on 7 February 2013 and came into force on 8 February 2013; it was issued by the then agriculture, food and environment ministry under final provision 5 of the animal health law, Ley 8/2003.
  • It applies on a voluntary basis to all sheep holdings in Spain; flocks that take part must follow the rules in annex II.
  • Article 4 lists five parts of the programme: breed selection programmes where TSE resistance is a breeding goal, certification and classification of breeding males by genotype, official recognition of resistant flock status, the ARIES database, and designation of a national reference laboratory plus authorised laboratories for sheep genotyping.
  • An allele is defined by the amino acids at PRNP codons 136, 154 and 171; annex I lists eight alleles (ARR, AHQ, ARH, ARQ, VRQ, ARK, ALQ, AHK), with ARR meaning alanine, arginine, arginine and VRQ meaning valine, arginine, glutamine.
  • Breeding males in participating flocks fall into three groups: group I is ARR/ARR, group II carries one ARR and no VRQ, group III carries neither; breeders' associations certify the genotype and group in the pedigree record using ARIES data, and certificates are valid across Spain.
  • Annex II requires every breeding male to be genotyped before use; males with any VRQ allele may not be used for breeding or semen and must go to slaughter, and the same applies to genotyped females with a VRQ allele; rare breeds can be exempted if their breed programme justifies it.
  • Annex III sets three flock resistance levels (level I: all animals ARR/ARR; level II: lambs only from ARR/ARR rams and ewes that are neither ARQ/ARQ nor VRQ carriers; level III: lambs only from rams with one ARR and no VRQ and ewes without VRQ), with random sampling of home-bred future breeders every year for level II and every two years for level I, sized from all animals in flocks of up to 25 to 59 animals in flocks over 1200.
  • Recognised resistance status is granted by the autonomous community, is valid nationwide, and is expressly not proof that a flock is free of TSEs; authorities must check every flock with status over a four-year cycle.
  • ARIES is a ministry-run internet and intranet application on the ministry's central server, holding at least animal identity, breed, holders, users, samples and results; animals not in a breed herdbook are recorded as crossbred.
  • Article 15 lets autonomous communities authorise public or private laboratories for sheep PRNP analysis and requires that programme genotyping be done only at the national reference laboratory or at designated authorised laboratories, which form part of ARIES.
  • The original article 14 designated the Laboratorio Central de Veterinaria at Algete (Madrid) as national reference laboratory for sheep PRNP analysis. Final provision 10 of Real Decreto 682/2026 of 26 August 2026 (BOE no. 241, 30 September 2026) replaced it with a reference to the ministerial order designating national reference laboratories, in force from 1 October 2026.
  • Orden PJC/1015/2026 of 28 September 2026, effective 1 October 2026, designates the Algete laboratory for PRNP gene analysis within this programme (heading II, item M.1, under animal and plant molecular genetics), and separately for TSEs (item C.1).
  • The decree repealed Real Decreto 1312/2005 of 4 November 2005 (BOE no. 278, 21 November 2005), which had made participation compulsory for high genetic value flocks, named the Algete central animal health laboratory as reference laboratory, and set subsidies such as up to 50 percent of costs for selection programmes and up to 450 euros per VRQ male removed from breeding. The 2013 decree contains no subsidy rules.
  • The preamble ties the programme to EU law: Commission Decision 2003/100/EC on minimum requirements for sheep TSE resistance breeding programmes (since repealed by Regulation 727/2007) and article 6a of Regulation 999/2001, added by Regulation 1923/2006. Article 6a lets member states introduce sheep breeding programmes for TSE resistance, which may include a framework for recognising flock resistance status.
  • Final provision 3 allows the minister, by order, to make breeding programmes compulsory for pedigree associations and flocks where EU law requires it and breed numbers allow.
  • The BOE analysis page lists only one later change to the decree, the 2026 rewrite of article 14, and no court rulings.
  • A ministry page, seen only as a search excerpt, says the Algete laboratory runs the programme's analyses under a procedure accredited by ENAC to UNE-EN ISO/IEC 17025.

Timeline

  1. 2003Commission Decision 2003/100/EC sets minimum requirements for sheep TSE resistance breeding programmes.
  2. 2004NEIKER publishes PRNP codon 136, 154 and 171 genotypes for 1297 Basque Latxa and Carranzana sheep, with ARR/ARR at 5 percent in Latxa.
  3. 2005Real Decreto 1312/2005 published, setting up the first national programme with compulsory participation for pedigree flocks; in force the next day.
  4. 2006Regulation 1923/2006 inserts article 6a on breeding programmes into Regulation 999/2001.
  5. 2013Real Decreto 21/2013 signed.
  6. 2013Published in BOE no. 33.
  7. 2013In force; Real Decreto 1312/2005 repealed.
  8. 2014End of the one-year window for existing flocks to apply for resistance status and for breed associations to say whether their programmes continue.
  9. 2026BOE no. 241 publishes Real Decreto 682/2026 and Orden PJC/1015/2026.
  10. 2026New article 14 in force; the designation order names Algete for PRNP analysis in the programme.
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