The effect of large doses of thiamine on the horse

Abstract

Extract

Thiamine, in common with other vitamins, has been used to treat conditions other than those knownto arise from specific vitamin deficiency. Recently, Mackay (1961) has claimed for this substance the previously unnoticed property of tranquillization, and has also found it to be of value in horses showing abnormal electrocardiographs. The writers have studied the complete paper submitted by Mackay to the New Zealand Racing Conference from which these conclusions were drawn. In his experiment a the number of animals was small, no controls were used, and some of the animals could be regarded as initially abnormal, a combination of factors which made his conclusions of doubtful validity. In an attempt to provide acceptable scientific proof or otherwise of Mackay's claims, a double blind experiment was conducted, in which each animal was medicated twice, once with thiamine and once with an inert substance, thus providing its own control. Because the assessment of the tranquillizing effect of a drug is largely a matter of personal observation, it was felt that the validity of the experiment would be enhanced if trained observers were used who did not know which medication the horse had received until after the observations had been completed.