PARENT SESSION

(T191) PUBERTY AND SEXUAL BEHAVIOR IN THE CASPIAN MINIATURE COLTS.

Dordari, Shahram¹, Amini, Fereydoon², Rezaie, Morteza¹, ¹ Agricultural Research & Education Organization, Tehran, Iran² Animal Science Institute, Karadj, Iran

ABSTRACT- The Caspian miniature horse is an ancient breed of horse, which was thought to be distinct for many years. This breed is a charismatic versatile little horse, existing only in small numbers, has now been recognized as holding an ancestral position in the history of the modern horse breeds, in all probability preceding that of the Arab horse. On the other hand Caspian horse is the only breed with the odd Chromosome numbers that means it may be the mixture of Equus Przewalski and Equus Caballus. The objectives of this study were to: 1-Determine age of puberty 2-Characterize seminal characteristics and sexual behaviors Puberty was studied using 7 colts of Caspian miniature horse Phenotype. .The evaluation was performed during two years on a completely healthy group of colts. Data for sexual behavior represented all 7 colts at puberty. Seminal collection were attempted every 2 weeks from 50 to 140 weeks .For all collections, times to erection, mount and ejaculation and seminal characteristics were recorded. Age at puberty was defined as the first ejaculate containing 50 million spermatozoa with >10% motile. The age at puberty averaged 24.6 months (12-34 months).Sexual behavior and seminal characteristics differed (p>0.05) between puberty and 2 years, except for time to erection,time to mount and percentage of motile spermatozoa. In this study the differences and similarities between this breed and the ponies were determined. Puberty, as determined by seminal characteristics, occurred between 11.5 and 14.5 months in Welsh pony stallions and between 12 and 23.6 months in quarter horse colts. As the other researches show, Puberty in horses varies a lot with breed. It can occur from 8-24 month and in pony breeds its shorter than other horse breeds. The average age of puberty on E.Przewalski is 31 and in E.Caballus is 12 months. The Caspian miniature horse was called Caspian pony for many years and shows the physiological similarities to horse breeds than ponies and to E Przewalski than E.Caballus.

KEY WORDS: Caspian horse, puberty, Sexual behaviuor, Colt ,stallion