The relationship between inbreeding and melanoma status (graded from 0 to 4) was analysed by various regression models. Analysed data referred to 296 grey Lipizzan horses originating from five state-owned studs (Austria, Croatia, Hungary, Slovakia and Slovenia) and with average inbreeding coefficient (F=0.107) calculated from extremely informative pedigrees (98% and 76% of horses had completely full pedigree in generation 10 and 20, respectively). In all regression models, in addition, the effects of stud (fixed) and age (covariate) were included. When all data were treated as one population, the estimates from linear and ancestral inbreeding models were not significant. Total inbreeding effect estimates (at F=0.125 and Fa=0.57) were 0.26 and 0.30 for the ancestral inbreeding and linear regression models, respectively. Heterogeneity among state-owned studs in inbreeding effects was also tested for both models and weak statistical significance was obtained for the interaction model with ancestral inbreeding (P=0.049). However, observed effect in the model with interaction was not consistent, did not yield in better model fitting and the obtained significance is probably just a statistical artefact. In general, although some indications about the relationship between ancestral inbreeding and melanoma were present, inbreeding does not appear to be a factor that substantially influences the expression of melanoma in Lipizzan horses.Regresijskim modelima analizirana je povezanost stadija melanoma (na skali od 0 do 4) i inbreedinga. Analizirani podaci odnose se na 296 sivih lipicanskih konja iz pet državnih ergela (Austrija, Hrvatska, Mađarska, Slovačka i Slovenija). Prosječna razina inbreedinga (F=0.107) izračunata je na temelju izuzetno informativnog pedigreea (98% jedinki imalo je potpuno poznat pedigre u generaciji 10, a 76% jedinki imalo je potpuno poznat pedigree u generaciji 20). U svim modelima uvažen je i utjecaj ergele (fiksni utjecaj) te starosti konja (kovarijabla). Kada se analiza koeficijenta regresije (regresija stadija melanoma na koeficijent inbreedinga) odnosila na populaciju kao jednu cjelinu, procjena linearnog koeficijenta regresije za inbreeding kao i za inbreeding predaka nije bila signifikantna. Kod razine inbreedinga F=0.125 i Fa=0.57, ukupna procjena linearnog utjecaja inbreedinga bila je 0.30, a utjecaja inbreedinga predaka bila je 0.26. Analizirana je i heterogenost utjecaja inbreedinga između državnih ergela i za interakcijski model sa inbreedingom predaka dobivena je slaba signifikantna interakcija (P=0.049). Ipak, dobiveni utjecaj u model sa interakcijom nije bio konzistentan, nije bolje objašnjavao nerazjašnjenu varijabilnost modela te je dobivena signifikantnost vjerojatno posljedica slučajnosti. Iz navedenog se može zaključiti, premda postoji indicija o povezanosti inbreedinga predaka i melanoma, da kod lipicanskih konja inbreeding nije čimbenik koji utječe na pojavu melanoma
