Effects of intravaginal progesterone devices on reproductive performance ofArabian ewes during non-breeding season.

摘要

The effects of intravaginalprogesterone devices on reproductive performance of Arabian ewes during a non-breedingseason is reported. Groups of 19 Arabian ewes each were given 0.3g medroxy acetateprogesterone (MAP) by intravaginal controlled internal drug release (CIDR) devicesconsisting of a nylon core surrounded by a silicone elastomeric impregnated with P4, orsponges embedded with 60 mg MAP for 14 days. Controls were not treated. Ewes givenprogesterone were injected 600 IU eCG upon withdrawal of devices. Fertile rams were thenmated with 5 of the treated ewes. No significant differences were found in fertility (60% vs.50%), lambing rates (60% vs. 50%) or litter size (1.0 vs 1.0) with progesterone treatments.However the estrous response with CIDR (95.2%) and sponge (91%) treatments was highercompared with controls (5.26%: P<0.05). The mean time of estrous onset in ewes given CIDRwas 34.74h compared with MAP sponge treatments (45.23h: h P<0.05). The highestincidence of estrus after removal of the devices in CIDR ewes was 24 to 36h (52.38%)whereas with sponges occurred at 48 to 60h (40.91%). Gestation length in ewes treatedwith sponges was 153.4d which was higher (P<0.05) compared with those given CIDR (148day). In treated ewes, progesterone serum cocentrations rose 3 days after insertion ofdevices. However, at 1 and 50d after insertion, after mating there were no differences inserum progesterone levels between treatments.