[Laryngeal hemiplegia in warmblood horses--a study of stallions, mares and their offspring].

Laryngoscopic examination during sedation was performed on 24 stallions and on their offspring (240 foals and 474 adult horses). Additionally the dams (n = 308) of 35 foals and 216 horses were examined. With the bilateral comparison of the arytaenoid movements the function of the abductory and adductory laryngeal muscles were evaluated and the left abductory dysfunction (idiopathic laryngeal hemiplegia, ILH) was divided into six degrees. The incidence and degree of ILH depended on age and the occurrence of the same dysfunction in the parents. Foals suffered in significantly lower number (24.7 per cent) than adult horses (49.7 per cent). The progeny of unaffected parents suffered significantly less from ILH (8.9 per cent of the foals, 39.6 per cent of the adult offspring) than did comparable progeny of affected parents (41 per cent of the foals, 60.9 per cent of the adult offspring). There was no correlation between the occurrence of ILH and sex. 120 horses were examined laryngoscopically and during work to get an information about the correlation between a visible ILH and the appearance of a typical inspiratory noise. 54.3 per cent of the horses with ILH had a typical inspiratory noise. 80.9 per cent of the horse with a typical inspiratory noise showed ILH.