Islandshästar med hosta och/eller prestationsnedsättning : skiljer de sig åt jämfört med andra raser?

Abstract: The purpose of the study was to investigate whether or not Icelandic horses are less severely affected in clinical symptoms of cough or decreased performance than other breeds of horses. A breed variation in chronic respiratory disease severity was suspected based on clinical experience at the Institution for surgery & medicine, large animal, SLU Uppsala. A retrospective journal study of 17 Icelandic horses and 17 Swedish Standardbred horses with chronic problems with cough and/or decreased performance compared several measurements of disease severity. The clinical signs, physical examination and laboratory testing results compared were respiratory rate, abdominal breathing, lung auscultation, endoscopy results, broncho-alveolar lavage (BAL) results and the blood gases pO2 and pCO2. All parameters were available for all 34 individuals except for the blood gases, which were analysed, in only four Icelandic horses and four Swedish Standardbred horses. The only parameters that appeared different between the two groups were respiratory rate and pO2. The four Icelandic horses, which had blood gases analysed, had more severe hypoxemia. But all had a greater inflammatory process in the lower airways as shown by the increased neutrophils in the BAL results compared to the 4 Standardbred horses. There was no difference between the 2 breeds of horse in the number of neutrophils in the BAL tests when all 17 horses in each group were compared, therefore it is likely that if one compared Icelandic horses with Standardbred horses having similarly severe inflammation there may not have been a difference. We did not have the opportunity to compare blood gases among individuals with equally severe inflammation as good controls. The difference in hypoxemia in only 4 horses with especially severe disease was thus not considered good proof of a difference between the 2 breeds. The mean respiratory rate was different between the two groups. Mean respiratory rate among the 17 Icelandic horses were 31,0 ± 9,7 compared with 16,8 ± 4,3 among the 17 Swedish Standardbred horses. In order to further consider this difference, the respiratory rate was measured in 23 clinical healthy Icelandic horses housed outside. The mean result was 16,4 ± 3,6. This is above than range accepted as the normal respiratory rate for horses of 8-16 per minute. This suggests Icelandic horses appear to have a higher respiratory rate normally and this may be exaggerated when they are examined inside where it is warmer. The higher respiratory rate among the 17 Icelandic horses in this study may only be mainly a breed variation and not necessarily indicate that they are more severely affected during chronic respiratory problems. Our conclusion was that there was insufficient proof found in a more controlled study to indicate that Icelandic horses are less severely affected by chronic respiratory disease that appeared as the clinical problems of cough or decreased performance. Further studies on respiratory rate and blood gas analysis may be useful in understanding the two differences noted in our study.