Reproduction in Domestic Animals - Facultad de Ciencias Veterinarias

16 t h International Congress on Animal Reproduction
Poster Abstracts 91
unsexed sperm was not statistically different in terms of cleavage rate
(sexed 50.5% versus unsexed 50.9%, P>0.05) and blastocyst
development rate (sexed 15.3% versus unsexed 19.1%, P>0.05). Of
the embryos produced in OPU-IVEP system, nine out of 34 sexed
fresh embryos (26.5%) and 5 out of 43 sexed frozen embryos (11.6%)
transferred to recipients established pregnancies, while 7 out of 26
unsexed fresh embryos (26.9%) and 6 out of 39 unsexed frozen
embryos (15.4%) transferred to recipients established pregnancies.
Among embryos produced by sexed spermatozoa, eleven buffalo
calves were delivered (10 females and 1 male) and 3 abortions (2
females and 1 male) recorded following embryo transfer. Among
embryos produced by unsexed spermatozoa and following their
transfer into suitable recipients, ten calves were delivered (6 females
and 4 males) and 3 abortions (3 males) were recorded. These data
would suggest that fresh as well as frozen-thawed embryos produced
from OPU derived oocytes have similar viability, together with a
similar potential to implant into the uterus and to establish
pregnancies. Finally, the birth of sex-preselected buffalo calves
indicated the full developmental competence of embryos produced in
OPU-IVEP system using sexed sperm. This work was jointly
supported by National Science and Technology Supporting Program
(No. 2006BAD04A18.), Guangxi Key Technology R&D Programs
(No. 0537001-1 and 0447001) and Guangxi University Key Program
(No. 2005ZD05).
P190
Serial ovarian ultrasonography in wild-caught wood bison
(Bos bison athabascae)
McCorkell, R*
Department of Veterinary Biomedical Sciences, Western College of
Veterinary Medicine, Canada
The Committee on the Status of Endangered Wildlife in Canada has
defined the wood bison (Bos bison athabascae) as a threatened
species. One method to ensure bison conservation is the
cryopreservation of gametes and embryos. To do this, a detailed
understanding of female bison reproductive physiology is required.
This study’s objectives were to determine if wood bison are amenable
to daily examination and to characterize ovarian function during the
non-breeding season. Ten two-year-old wood bison heifers obtained
from Elk Island National Park were placed in a corral adjacent to a
handling system designed for restraining bison. The handling system
was left open to the corral allowing the bison to freely explore it for 2
months. Active acclimation followed for a 2-week period during
which the bison were herded daily through the handling system and
rewarded with whole oats. Finally, the bison were restrained in the
handling system and then rewarded with whole oats upon release.
Once conditioned, daily transrectal examination of the ovaries was
successfully completed in 100% of attempts for 30 days (January-
February) using a B-mode scanner with a 5-10 MHz linear-array
transducer (SonoSite Titan, Markham, Ontario). Follicle size and
numbers were recorded, and individual follicles were identified
serially. Blood samples were collected daily and the serum was
analyzed for FSH and cortisol concentrations. In 3 bison, ovarian
follicles did not exceed 5 mm in diameter during portions of the study,
2 had elevated serum cortisol concentrations relative to the others and
the third had the lowest body weight of the 10. Therefore, data from 7
animals was used. There were non-random changes (P