Age-related linear and nonlinear modelling of semen quality parameters in Miranda donkeys

In endangered donkey populations, reproductive performance is one the most important areas to study, provided its connection with conservation opportunities. Among traits, knowledge on evolution of seminal qualitative and quantitative parameters may achieve a particular relevance given implication improved or more efficient fertility fecundation chances. The aim present study was model gonadosomatic index along age in Miranda donkeys. Forty semen collections from 8 donkeys 2.8 21.6 years age, were fitted eleven linear nonlinear models. Cubic function modelling reported best-fitting properties for almost all variables, except sperm concentration (exponential model). presented slightly higher ability capture interindividual variability than less parametrically complex models computationally models, such as exponential logarithmic. Senility course larger numbers abnormal morphology spermatozoa, also reduced motility.HighlightsTestis reach mature size rapidly which be ascribed breed factor.Age promotes ejaculate volume increase reduction.Reduced motility ascribe increased spermatozoa.Major age-related changes are linked testicular functions degeneration.