Sexual behaviour of bull : A review

Abstract

The reproductive activity of bulls depends on internal (genetical, physiological) and external (social environment, sexual stimulation) factors, explaining important interindividual variations of sexual efficiency and semen production. During the development period (prepubertal period), important social deprivation (rearing in individual pens or absence of heterosexual contact) has no unfavorable effect on later sexual behaviour of the bull, unlike in other species (notably in the ram). In fattening bulls, homosexual behaviour can have notable negative economical consequences (injuries, prejudicial to growth). In adulthood, socio-sexual relationships within a group of bulls is mainly dependant on age and population density. This kind of rearing, depending on the age of meeting, can influence the intraspecific aggressivity and hierarchical stability, which are related to the efficiency of bulls in sexual competition in natural mating. Fertility in natural mating depends on the semen quality and on the sexual efficiency of bulls. Regarding artificial insemination, the techniques used for rearing bulls and for their sexual stimulation at the time of semen collection are well understood, as are the risks of interspecific aggressivity (man- animal relationships). The lay-off during the expecting of results of testage have not unfavorable consequences on later sexual behaviour, neither on semen production. This technic allows an important economy. Many studies about the sexual behaviour of bulls and its consequences allow an optimum use of sire, in natural mating like in artificial insemination, and adapted rearing conditions for fattening bulls.