Materials and methods The study was sanctioned by the Ethical Com mittee for Animal Experiments, Uppsala, Sweden. Horses Nine Standardbred and nine Icelandic horses were included in the study. The Standard bred horses were owned by the Department of Clinical Sciences and kept in box stalls with a daily turn out in a paddock. The horses were fed a standardized diet con sisting of hay and concentrate and provided water ad libitum. The Icelandic horses were privately owned and mainly in free range in a paddock but were also kept in box stalls on a regular basis. These horses were fed grass haylage and provided water ad libitum. All Standardbreds were sedentary horses whereas eight of the Icelandic horses performed lighter exercise three to five times a week and one was sedentary.
Four of the Standardbred horses and four of the Icelandic horses were included in the transportation study. None of the horses included in the study showed any signs of disease on the clinical examination that was per formed before the start of the study. Blood pressure measurement devices Systolic, diastolic, and mean indirect arterial pressures were obtained with Cardell and HDO oscillometric monitors. For the trans portation study only the HDO device was used. For each monitor, indirect blood pressure was obtained from cuffs Drug_discovery placed at the base of the tail according the manufacturers instructions. The cuff size for the Cardell device was 11 cm and 8 cm for the HDO device. Both devices automatically inflate an occluding cuff and use the oscillometric measurement technique for determination of systolic, diastolic, mean arterial blood pressure and heart rate.
The cuffs were reposi tioned as needed to acquire data acceptable to the in ternal sensor of the monitor. The same cuff size accompanied each device through all measurements. Experimental protocol The blood pressure measurements and the sample col lection were performed between March and April 2011, before the horses had access to summer pasture. The ar terial systemic blood pressure was measured between 6 and 9 am on two separate days. The cuffs were placed on the base of the horses tail while the horse was standing in the box stall. Five consecutive determinations of systolic and diastolic blood pressure were performed on each horse, using both devices. On the first day of the study, the starting order in which of the two blood pressure measurement devices were used was randomized by raffle. The next day the starting orders of the devices were switched. In each horse, blood samples were drawn immediately after both blood pres sure measurements had been completed. Transportation study The horses were transported in a two horse trailer for one hour to a new stable were they stayed overnight.