Effects of castration on the behaviour of male llamas (Lama glama)

Abstract

Objective: The aim of the study was to prove the effects of castration on behaviour and hormone levels in sexually mature and immature Llama males. Material and methods: The study comprised six sexually mature and six sexually immature llama males. Their social and sexual behaviour was observed before and after castration. Testosterone levels were analysed regularly. Results: The percentage of low social distances was significantly lower in mature males and increased in both groups after castration as well as the number of direct body contacts. Short agonistic interactions and the percentage of fights with clear result (one male was the winner or looser) decreased after castration in mature males. In both groups order of rank changed after castration. Before castration all mature males mated the female without breaks. After castration they interrupted copulations several times and total time of mating was decreased. Immature males showed short mating times with many interruptions before castration. The testosterone level changed between the months of observation in the mature male group. In the mature male group blood testosterone level was 4.1 ng/ml (+/- 2.8), and in the immature group it was 1.1 ng/ml (+/- 1.0). There were no correlations between testosterone level and order of rank. Conclusion and clinical relevance: Mature and immature males differed significantly in behaviour and hormone levels. Castration did improve social behaviour as the number and intensity of agonistic interactions decreased. Sexual behaviour was also significantly affected by castration in mature males. It can be concluded that keeping and handling of geldings is less problematic. Therefore, castration can be recommended as a management tool after 12 months of age, but before sexual maturity.