Effect of new and used cidr devices on ovarian follicular growth and fertility in seasonally anestrous crossbred ewes and ewe lambs

The aim of the present study was to examine the effect of progesterone priming with new or used controlled internal drug release (CIDR) device for 14 days on ovarian follicular growth and fertility traits in Rahmani x Romanov crossbrede wes and ewe lambs during the non-breeding season. Fourteen ewes and ten ewe lambs were divided randomly into four groups based on their age and body weight. First group (GI) was treated with a new CIDR device containing 300mg one (n=7 ewes), and the second group (G2) received a previously used CIDR (n=7 ewes). The CIDRs were left in situ for 14 days Both groups (GI +G2) were given 750 IU i.m. injection of pregnant mare serum gonadotropin (PMSG) at CIDRs. withdrawal. The third group (G3) received a new CIDR device containing 300mg progesterone (n=5 ewe lambs) and fourth group (G4) received a previously used CIDR (n=5 ewe lambs). Both groups (G3+G4) were given 4pg i.m.injection of GnRFI at CIDR removal. Estrus was detected using normal rams with crayon markers. Blood samples were collected from the animals at days 0 (CIDR removal), +1 from ewe lambs, +3 from ewes, and +10 from both ewes and ewe lambs. Ovarian structures were recorded by ultrasonography (US) at the same pervious times. Ewes that received either new or used CIDR had more (P0.05) total number of follicles (TNF) on d +3 ultrasound scanning (US2) than d 0 (US1). New and used CIDRs had no effect on the number of small follicles (¡Ü3mm) either in ewes or ewe lambs. Therefore, ewes had more (P0.01) large follicles (mm) on d +3 (US2) than d 0 (USI). However, type of CIDR had no effect on the diameter of large follicles (DLF) either in ewes or ewe lambs. Conception rates were similar (71 %) for ewes treated with either new or CIR devices. Similar trend was found in ewe lambs with conception rates of about 40%. No significant differences in progesterone concentrations were found at the time of CIDR removal in all animal groups. At d +10 after CIDR removal ewes had higher (P0.01) concentrations of serum progesterone, greater number (PO.05) of CLs, and greater(p0.05) mean area of CLs compared with ewe lambs. Results indicate that the re-use of CIDR for 14 days to induce estrus durig non-breeding season in sheep is avalid choice and increases the economic return with no negative effects on the ovulatory follicles and conception rates.