When observing free-ranging jacks, insertion latency, the number of thrusts and the total time mounted has been described as similar to that of stallions. However, in a hand-mating situation and in particular in situations of mule production (jacks breeding with mares) our experience has been that all jacks take an extremely long time until erection and mounting, but once mounting is achieved, ejaculation is generally easily obtained (Tibary ''et al'', 2005; Tibary, 2006). | When observing free-ranging jacks, insertion latency, the number of thrusts and the total time mounted has been described as similar to that of stallions. However, in a hand-mating situation and in particular in situations of mule production (jacks breeding with mares) our experience has been that all jacks take an extremely long time until erection and mounting, but once mounting is achieved, ejaculation is generally easily obtained (Tibary ''et al'', 2005; Tibary, 2006). |