This study compared the effects of intravaginal and intravenous routes of oxytocin (OT) administration in 46 oestrous-induced Santa Inês ewes (6-day treatment with progestin-releasing intravaginal sponges and a single injection of 200 IU of eCG at the time of sponge removal) that underwent transcervical embryo recovery 6-7 days after oestrous onset and mating. All ewes received 37.5 μg of d-cloprostenol via latero-vulvar route, and 1 mg of oestradiol benzoate i.m. 16 hr before and 50 IU of OT 20 min before non-surgical embryo recovery (NSER), with OT being administered intravenously (n = 21) or intravaginally (n = 21). An overall oestrous response was 95.6% (44/46), and adequate cervical retraction could be accomplished in 78.6% (33/42) of ewes. The percentage of successful NSER procedures was 57% (24/42) or 72.7% (24/33) of animals with sufficient cervical retraction. The duration of NSER procedure averaged 28 min (range: 17-40 min) and ~96% of flushing fluid could be recovered (range: 85%-100%). Out of 18 ewes that could not undergo NSER, 12 (66.6%) presented various anatomical barriers, whilst the other 33.4% did not present these barriers and still could not be traversed. Excluding the ewes with those anatomical features, the overall success rate of NSER was 80% (24/30). The route of OT administration had no effect on NSER efficiency or the ease with which transcervical embryo flushing was performed. Both routes of OT administration can be used for cervical dilation protocol. Discarding ewes with anatomical features precluding cervical penetration is highly recommended to increase the efficacy of NSER in sheep. K E Y W O R D S cervical relaxation, sheep, transcervical embryo collection, uterine flushing | 1231 PRELLWITZ ET aL. How to cite this article: Prellwitz L, Zambrini FN, Guimarães JD, et al. Comparison of the intravenous and intravaginal route of oxytocin administration for cervical dilation protocol and non-surgical embryo recovery in oestrousinduced Santa Inês ewes. Reprod Dom

Antimetastatic activity, high selectivity and cytotoxicity for human tumor cell lines make ruthenium(ii) complexes attractive for the development of new chemotherapeutic agents for cancer treatment.

This study assessed the efficiency of cervical relaxation protocol using none, half or full dose (1.0 mg) of oestradiol benzoate in Dorper ewes subjected to non‐surgical embryo recovery (NSER). Thirty‐six pluriparous ewes received progestogen sponge (60 mg) for 9 days plus eCG administration (300 IU i.m.) 24 hr before sponge removal. Ewes were not mated and were randomly assigned to receive at 16 hr before NSER 37.5 µg d‐cloprostenol i.m. and different doses of oestradiol benzoate: 0.0 mg (0EB group; n = 12); 0.5 mg (0.5EB group; n = 12) or 1.0 mg of oestradiol (1.0EB group, n = 12). All ewes received oxytocin (50 IU) i.v. 20 min before NSER, which was performed 8 days after sponge removal. Corpora lutea were counted by transrectal ultrasonography 24 hr before NSER. After procedure, the ewes were kept in natural breeding period to check their post‐NSER fertility. NSER was performed in 91.7% (33/36) of the animals with overall fluid recovery efficiency over 97% (p > .05). The cervical transposing with Hegar dilator was longer (p < .05) in 0EB (4.2 ± 0.3 min) compared to 0.5EB (1.7 ± 0.3 min) and 1.0EB group (1.5 ± 0.3 min). The cervical transposing with mandrel/catheter was longer (p < .05) in 0EB (2.4 ± 0.5 min) than 1.0EB group (1.3 ± 0.5 min). Overall duration of uterine flushing was 25.4 min with structure recovery rate of 43.5%, with no difference among groups (p > .05). The post‐NSER fertility was higher (p < .05) in 0.0EB (90%) than 0.5EB group (36.4%). In conclusion, NSER can be successfully performed in Dorper ewes by using a cervical relaxation protocol without oestradiol benzoate.

We report on the effect of postgrowth annealing on the magnetic anisotropy of Fe31Co69 thin epitaxial films, 1–9 nm thick, and grown on GaAs(001) substrates. Hysteresis curves obtained by means of the magneto-optical Kerr effect reveal an in-plane uniaxial magnetic anisotropy with the easy axis typically along the [110] substrate direction. The effective in-plane and perpendicular anisotropy constants, Kueff and K⊥eff, exhibit a steep quasilinear increase with the annealing temperature. Annealing a 1.9-nm-thick film for 10 min at 300 °C results in an increase in Kueff from the as-grown value of 8.9×103 to 1.1×105 J/m3. The slope of Kueff versus annealing temperature increases approximately as the inverse of the film thickness. These observations can be accounted for by a thermally induced structural modification occurring in the ferromagnet-semiconductor interface. Film-strain measurements performed by x-ray grazing-incidence diffraction indicate that the postgrowth annealing evolution of Kueff and K⊥eff are not predominantly induced by a magnetoelastic effect associated with strain changes in the thin film, but rather by modifications of the interface atom bonding, leading to an enhanced magnetocrystalline anisotropy at the ferromagnet-semiconductor interface.

This paper reports results obtained on exchange-biased IrMn/Al2O3/Co films deposited by magnetron sputtering, where the thickness of the non-magnetic insulator layer, tAl2O3, was varied. Ferromagnetic resonance and static magnetization measurements were used to study the exchange interaction between the antiferromagnet (IrMn) and ferromagnet (Co) layers. X-ray diffractometry and x-ray reflectometry as well as high-resolution transmission electron microscopy were employed for structural characterization of the films. It was found that the IrMn/Co exchange coupling decreases very abruptly with tAl2O3 being the exponential decay length at least four times smaller than the values previously reported for exchange-bias systems. Such a rapid suppression of the coupling is explained in terms of the prompt loss of the direct contact between the antiferromagnet and the ferromagnet with tAl2O3.