The synchronization of oestrus and subsequent fertility in ewes following treatment with a synthetic prostaglandin analogue (ONO 453)

The effect of treatment by prostaglandin analogue (ICI–80, 996) or progestagen (SC-9880) on ovulation and fertilization in cyclic ewes

“…Lightfoot et al (1976) have presented results clearly demonstrating that fertility is depressed in ewes mated at the first oestrus after treatment with Cloprostenol. Hughes et al (1976), on the other hand, have reported essentially normal lambing rates follow-ing the use of a synthetic analogue (ONO 453) with natural service as the method of breeding.…”

“…The progestagen sponge has been employed in this country to practical advantage (Gordon, 1975). It has been suggested that prostaglandins may provide an alternative to progestagens as agents for synchronizing oestrus in cyclic ewes (Haresign, 1976;Hughes, Lucas & Notman, 1976). Cloprostenol (I.C.I.…”

Synchronisation of oestrus and fertility in sheep treated with progestagen-impregnated implants, and prostaglandins with or without intravaginal sponges and subcutaneous pregnant mare's serum

“…The low conception rates in the PG group, less than half that observed in untreated ewes and roorer than either progestagen treatment, indicates that PGs are unlikely to be used in preference to progestational techniques as a means of oestrus synchronisation. Some workers have found high fertility after using PGs (Haresign et al 1976;Hughes et al 1976), but generally fertility is lower. (Fairnie et al 1976;Lightfoot et al 1976; J.…”