Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/15/2005
Publication Date: 10/29/2005
Citation: Blackburn, H.D., Mcallister, J.M., Purpera, M., Landry, A., Olcott, B., Bondioli, K., Bushnell, S., Godke, R.A., Loetz, E. 2005. Collection and freezing of angora embryos for the usda animal germplasm repository. ASAS Southern Section Meeting, February 4-8, 2006. Journal of Animal Science. 84(Supl 2):24-25. Interpretive Summary: The efficiency of developing germplasm collections for all species is dependent upon using protocols that can maximize the collection efforts. For Angora goats it is critical that semen and embryos be collected for the repository due to the difficulty that would be encountered in regenerating the fiber characteristics of this breed from semen only. Therefore, this study evaluated the effect of Gonadotropin Releasing Hormone (GnRH) on corpora lutea (CL) and number of embryos harvested from 18 Angora does. The does were randomly divided into two treatment groups, with Treatment A receiving 50 micrograms of GnRH intramuscularly at the time of the first natural mating and Treatment B not receiving GnRH at breeding (Control group). Day-7 embryos were surgically collected via mid-ventral laparotomy. Recovered embryos were evaluated, assigned embryo quality scores and cryopreserved using a standard laboratory procedure. No significant differences were found between the control and GnRH treatment indicating that this procedure did not increase embryo harvest efficiency.
Technical Abstract: The objective of this study was to evaluate the effect of administering Gonadotropin Releasing Hormone (GnRH; Cystorelin) to caprine does at the time of breeding on the number of corpora lutea (CL) and embryos at the time of collection. During the regular breeding season (December), 18 randomly cycling mature Angora does and two mature bucks were assigned to this study. To synchronize estrus into weekly embryo collection groups, a polymer-based progesterone implant (Crestar) was placed subcutaneously in the ear of does for 7 days and then they were given 15 mg of prostaglandin F-two-alpha (Lutalyse) 24 hours before the implant was removed. FSH was administered intramuscularly in eight decreasing doses (1.5, 1.5, 1.5, 1.25, 1.25, 1.0, 1.0, and 1.0 ml) (0.88 mg/ml) 12 hours apart beginning 48 hours prior to Crestar implant removal. The does were randomly divided into two treatment groups, with Treatment A receiving 50 micrograms of GnRH intramuscularly at the time of the first natural mating and Treatment B not receiving GnRH at breeding (Control group). Day-7 embryos were surgically collected via mid-ventral laparotomy. Recovered embryos were evaluated, assigned embryo quality scores and cryopreserved using a standard laboratory procedure. The embryos were then transported via over night courier to the USDA Animal Germplasm Repository at Ft. Collins, Colorado for storage. In summary, there was no advantage in using GnRH at the time of mating on number of CL per doe and the number of embryos per doe in this study (Table). Unexpectedly, one of the two males had markedly reduced embryos produced per doe at mating. In the does that produced embryos, seven donor does produced 76 good equality embryos for cryopreservation, for an average of 10.9 embryos per female. Treatment # does # CL Does with # UFOs # embryos group mated (avg/doe) embryos (avg/doe) (avg/doe) GnRH 9 90 (10.0) 4 52 (5.8) 37 (4.1) No GnRH 9 124 (13.8) 3 46 (5.1) 39 (4.3) Total 18 214 (11.9) 7 98 (5.4) 76 (4.2)