Horses have inhabited Iberia (present-day Spain and Portugal) since the Middle Pleistocene, shaping a complex history in the region. Iberia has been proposed as a potential domestication centre and is renowned for producing world-class bloodlines. Here, we generate genome-wide sequence data from 87 ancient horse specimens (median coverage = 0.97X) from Iberia and the broader Mediterranean to reconstruct their genetic history over the last ~26,000 years. Here, we report that wild horses of the divergent IBE lineage inhabited Iberia from the Late Pleistocene, while domesticated DOM2 horses, native from the Pontic-Caspian steppes, already arrived ~1850 BCE. Admixture dating suggests breeding practices involving continued wild restocking until at least ~350 BCE, with IBE disappearing shortly after. Patterns of genetic affinity highlight the far-reaching influence of Iberian bloodlines across Europe and north Africa during the Iron Age and Antiquity, with continued impact extending thereafter, particularly during the colonization of the Americas.

Horses (n=35) underwent orchidectomy in a single institution with a re‐sterilised LSA as sole means of haemostasis. During the surgery, the gross quality of the seal, the stickiness of the forceps to the tissues, bleeding/oozing from the stump and the need for a subsequent application in already severed spermatic cord were assessed for haemostasis quality. After surgery, physical parameters (appearance of the mucous membranes, quality of the peripheral pulse, heart rate, respiratory rate, rectal temperature and blood dripping from the incisions), haematology or packed cell volume and total protein were monitored to assess signs of bleeding or any other condition. For cleanliness and asepsis assessment, signs of surgical infection were recorded. Complications during surgery were mild degree of sticking of the LSA forceps to the tissues and dulling of the blade. There was no need to reapply LSA a second time except in one horse. This means a haemostasis complication rate of 2.85 per cent of the horses. No postoperative bleeding was detected. Only two horses with fever had associated signs of surgical site infection. This means an infection rate of 5.71 per cent of the horses.