Photoperiod and melatonin treatments for controlling sperm parameters, testicular and accessory sex glands size in male Iberian ibex: A model for captive mountain ruminants

Abstract This study examines whether photoperiod and/or melatonin treatments can improve sperm variables outside the breeding season in the Iberian ibex–a model species for wild mountain ruminants–thus helping in the collection of high quality sperm beyond the normal breeding season for depositing in genetic resource banks. Adult Iberian ibex males ( n =17) were divided into four treatment groups: (1) controls under the natural photoperiod (control group; n =4), (2) treatment with melatonin implants on December 22nd, February 22nd and April 22nd (group WS-M; n =5), (3) treatment with short photoperiod cycles, i.e., 2 months of long days followed by melatonin implants (to emulate 2 months of short days) throughout the year (group PHPld+M; n =4), and (4) treatment with melatonin implants on June 22nd and August 22nd (group SS-M; n =4). The interaction treatment x season had a strong influence on testis size ( P P P P