Impact of abomasal nematodes on roe deer and chamois body condition in an alpine environment

Abomasal helminths were examined from 101 roe deer and 43 chamois, shot or found-dead, in the period July-November 1993-95, in the Parco Naturale Paneveggio Pale di San Martino (Italian Eastern Alps). Twelve helminth species were observed in both roe deer and chamois. For both host species, discriminant analysis, using the abundance of each parasite species in the hosts, failed to distinguish between subjects from each of the three study years. For 44 roe deer and 27 chamois data on body weight, body length, foot length, withers height, thoracic circumference and kidney fat index were also available. Principal Component Analysis was performed on the biometrical data in order to group related variables into a few compound variables. In both host species it was possible to identify two principal components, with an explained variance > 80%: the first component, led by body length, was an expression of skeletal development and the second, led by kidney fat index, of nutritional status. Parasite abundance and richness appeared to be negatively correlated with the scores of both skeletal and nutritional Components in the two host species, although only the correlation between parasite abundance and the scores of the nutritional component in roe deer was statistically significant (Spearman r = -0.411; p < 0.05). These results support the susceptibility of roe deer to abomasal helminths, which could be important considering the spatial and nutritional interspecific competition between domestic and wild ruminants often recorded in alpine environments.