Effect of service and vaginal-cervical anesthesia on estrus duration in dairy goats

The object of this experiment was to study the effect of sterile service and vaginal and cervix anesthesia on estrus duration in dairy goats. During the fall season 21 Nubian goats (9 nulliparous and 12 multiparous) were randomly assigned to 1 of 3 treatment groups (n = 7 animals per group). The following groups were formed: service (SER), vaginal and cervix anesthesia (VCA) and control (CON). Estrus was synchronized using fluorgestone acetate intravaginal pessaries (FGA, 30 mg) over a 14-d period. Estrus was detected using a vasectomized buck at 6-h intervals over 5 d after pessary removal (at 0600, 1200, 1800 and 2400 h). In the SER group the male was permitted to service each female. In the VCA group the vagina and cervix of the does were anesthesied, after which the male was permitted to service the females. Both treatments were done once within the first 12-h initiation of estrus. Does were permitted to be mounted only in the control group (CON). Estrus duration for SER, VCA and CON groups was (mean +/- SD) 24.0 +/- 10.9, 42.0 +/- 15.9 and 40.3 +/- 10.8 h, respectively. The SER group was significantly different from the VCA and CON groups (P < 0.01); however, the VCA group was not different from the CON group (P > 0.05). It is concluded that service shortens the duration of estrus due to the mechanical effect of the penis against the vagina and cervix, and not to the accessory gland fluid.