The Viking Hoard doping case, in which a horse was nobbled with an overdose of the tranquilliser acepromazine (ACP) in Ireland in October 2018, concluded on Thursday when the trainer Charles Byrnes lost his appeal against a six-month ban for “inexcusable” negligence when he left his horse unattended for “20 to 25 minutes” before the race. Questions surrounding the case remain, however, not least about “substantial” lay bets on another of Byrnes’s runners at Sedgefield on 2 October 2018, which won an undisclosed amount when the horse, Thosedaysaregone, was pulled up. The Irish Horseracing Regulatory Board’s referrals committee – the equivalent of the British Horseracing Authority’s disciplinary panel – accepted at its initial hearing in January that Byrnes had no direct involvement in the doping of Viking Hoard. The gelding returned a positive test for ACP that was found to be 100 times over the threshold level after being pulled up in a race at Tramore on 18 October 2018. Viking Hoard drifted in the pre-race betting from 4-1 to 8-1 and was also laid heavily on Betfair via an offshore “white label” site. One account, identified as being linked to an individual “in a distant part of the world” with links to match-fixing in other sports, staked €34,889 [£30,200] to win €3,200 [£2,850] if Viking Hoard was beaten, suggesting “substantial confidence”, according to the referrals committee, that the horse would not win. It also emerged during the case that the same account risked €30,279 to win €12,000 before Viking Hoard was beaten in a race at Sedgefield a fortnight earlier, having drifted from 3-1 to 10-1, and also that “another runner from Mr Byrnes’ stable at that meeting was successfully laid against a substantial risk on the exchanges”. Byrnes’s only other runner on the Sedgefield card was Thosedaysaregone, a 5-4 favourite, who was pulled up four out. Kevin Brouder, his jockey, subsequently reported to the stewards that his saddle had slipped, “causing him to lose his irons and so he pulled the gelding up”. The IHRB was initially alerted to the suspicious betting patterns around Viking Hoard’s race at Tramore by the BHA’s integrity department, which monitors activity on Betfair and other exchanges. The BHA’s team also identified the account responsible for the bets against Viking Hoard, which raises the question of whether it was the same account which also placed a substantial bet against Thosedaysaregone an hour earlier. The BHA has a long-standing policy of refusing to offer any comment on either past or ongoing investigations, and stuck to it firmly on Thursday when asked if the races involving Byrnes’s runners at Sedgefield on 2 October 2018 are, or have been, the subject of an investigation. Byrnes, meanwhile, will lose his licence for six months from 4 March, after the IHRB’s appeals panel dismissed his appeal against the penalty imposed on him at the original hearing. In a verdict published on Thursday, the panel said that Byrnes’s behaviour in leaving Viking Hoard unattended before his race at Tramore was “simply inexcusable”. It also ordered that Byrnes should forfeit his €500 deposit, and pay an additional sum of around €1,500 towards the IHRB’s costs. Betfair stopped accepting “lay” bets on racing from white-label sites in 2019.