01984naa a2200265 a 450000100080000000500110000800800410001910000200006024500660008026000090014652012870015565000150144265000170145765000150147465000140148965000170150365000170152065000100153765000140154765300170156165300190157865300210159770000190161877300810163720729552023-04-28       1971    bl uuuu     u00u1 u    #d1 aFLETCHER, I. C.  aEffect of rams on the duration of oestrous behaviour in ewes.  c1971  aThe effect of rams on the duration of oestrous behaviour was studied with oestrogen-treated spayed ewes. Different degrees of association between ewes and rams influenced the duration of oestrus in two ways. First, the duration of oestrus measured by teasing ewes with active rams once every 4 hr was shorter when ewes and rams remained together than when they were kept apart between observations. Continuous contact with rams appeared to limit the duration of oestrus by inhibiting the neural mechanism controlling the expression of oestrous behaviour. Second, the duration of oestrus measured by teasing ewes individually every 4 hr and keeping them with rams between observations was longer than that measured when ewes were kept in continuous uncontrolled association with rams. Regular teasing probably resulted in a longer duration of oestrus because it eliminated competition between ewes and rams and overcame the apparent unwillingness of rams to continue to mate with the same ewes for the full duration of their oestrus. The incidence, time of onset, and duration of oestrous behaviour all responded linearly to increasing doses of oestrogen, but the slopes of these dose-response relationships were not affected by the different methods of measuring oestrous behaviour.  aCastration  aPharmacology  aPhysiology  aPregnancy  aProgesterone  aReproduction  aSheep  aEstradiol  aDrug effects  aOestrous cycle  aSexual behaviour1 aLINDSAY, D. R.  tJournal of Reproduction and Developmentgv. 25, n. 2, p. 253-259, May. 1971.