Age and treatment on the day of embryo transfer in recipient mares affect likelihood of pregnancy.

Objective: This retrospective evaluation of data from a large commercial embryo transfer facility aimed to determine the extent to which age and treatment on the day of embryo transfer in recipient mares influence the likelihood of pregnancy.

Material And Methods: Embryo recovery was carried out on days 8-10 post-ovulation using transcervical uterine flushing. Recipient mares grouped according to their age were treated once on the day of embryo transfer (Day 3-8 post ovulation) and were assigned randomly to 1 of 3 groups: Mares in Group A (n=101) received antispasmodic, antimicrobial, and anti-inflammatory drugs.

Equine produced blastocysts: relationship of embryo morphology, stage and speed of development to foaling rate.

Context: Information on factors associated with developmental competence of equine in vitro -produced (IVP) blastocysts is lacking.

Aims: To determine the relationships of stage, grade, day of development, and specific morphological parameters of equine IVP blastocysts, to pregnancy and foaling rates.

Methods: Photomicrographs of 316 IVP embryos with known pregnancy outcomes were scrutinised individually by four observers.