The fertility achieved with nonsurgical AI and frozen-thawed ram sperm is influenced by the estrous synchronization protocol, semen cryopreservation diluent, and age and breed of the sheep

Authors: Purdy, Phil; Spiller, Scott; MCGUIRE, EUGENIE - Desert Weyr, Llc; MCGUIRE, KENYON - Desert Weyr, Llc; KOEPKE, KALLI - University Of Wyoming; STOBART, ROBERT - University Of Wyoming; Burke, Joan; ACHARYAF, MOHAN - University Of Arkansas; BEEMER, TERESA - Animal And Plant Health Inspection Service (APHIS); MOSS, GARY - University Of Wyoming; LAKE, SCOTT - University Of Wyoming; Blackburn, Harvey

Submitted to: Biology of Reproduction
Publication Type: Abstract Only
Publication Acceptance Date: 4/11/2017
Publication Date: 7/1/2017
Citation: Purdy, P.H., Spiller, S.F., Mcguire, E., Mcguire, K., Koepke, K., Stobart, R.H., Burke, J.M., Acharyaf, M., Beemer, T., Moss, G., Lake, S., Blackburn, H.D. 2017. The fertility achieved with nonsurgical AI and frozen-thawed ram sperm is influenced by the estrous synchronization protocol, semen cryopreservation diluent, and age and breed of the sheep. Biology of Reproduction. http://www.ssr.org/sites/ssr.org/files/uploads/attachments/node/482/ssr2017abstracts.pdf.

Interpretive Summary: Low fertility with sheep nonsurgical artificial insemination has slowed genetic progress when compared to cattle or swine. Consequently, efficient use of gene bank samples held by the National Animal Germplasm Program is also limited. Meta-analysis of nonsurgical sheep AI from 2003 to 2016 was performed to elucidate significant factors contributing to fertility. We are able to successfully perform nonsurgical artificial insemination that results in fertility, as determined by lambing rates, but our research determined that breeds of sheep respond differently to estrous synchronization protocols and timed inseminations. Consequently, in order to make substantial progress in non-surgical AI further exploration into biological and management interactions will be necessary.

Technical Abstract: Low fertility with nonsurgical AI has slowed genetic progress when compared to cattle or swine. Efficient use of gene bank samples held by the National Animal Germplasm Program is also limited. Meta-analysis of nonsurgical sheep AI from 2003 to 2016 was performed to elucidate significant factors contributing to fertility. Logistic regression analyses included the effects of the type of AI (surgical or nonsurgical; n = 918 inseminations), type of non-surgical AI device (spiral swine catheter or sheep and goat AI gun), timing of the AI relative to removal of the progesterone devices (CIDR or sponge), type of progesterone device used for estrous synchronization (CIDR or sponge), timing of PMSG administration (coincident with, 24 or 48 h prior to removal of progesterone device), ram and ewe age (1 to 9 and 1 to 10 years, respectively), sheep breeds (Black Welsh Mountain, n = 222; Hampshire, n = 11; Katahdin, n = 62; Rambouillet, n = 623), and the type of semen cryopreservation diluent (200 mM Tris egg yolk glycerol (TEYG), 300 mM TEYG, or skim milk egg yolk glycerol (SMEYG)). Non-significant effects for type of AI, progesterone device, or ram age were found (P > .05) but other treatment effects were significant (P < .01). Not all experiments were balanced across breeds, therefore breed-by-breed analyses were performed to identify combinations of treatments that would yield the highest fertility rates. For Rambouillet nonsurgical AI fertility (28% lambing) is maximized when PMSG was administered at the time of progesterone device removal, AI was performed at 12 to 24 hours post estrus using a spiral swine catheter, ewes were 3 to 4 years old, and either SMEYG or 200 mM TEYG diluent was used. AI for Black Welsh Mountain sheep was maximized (32% lambing) when PMSG is administered 24 h prior to the removal of the progesterone device, a single AI was performed at 53 h post removal of the progesterone device using a sheep and goat AI gun, when ewes were 3 to 4 years old and the ram semen was frozen in either SMEYG or 200 mM TEYG diluent. Non-significant but maximum treatment effects for Hampshire and Katahdin were achieved (10% and 8% fertility, respectively) using PMSG administered 24 h prior to removal of the CIDR, single inseminations performed at 53 h post CIDR removal using a sheep and goat AI gun and semen frozen in 200 mM tris egg yolk glycerol diluent. These results suggest breeds respond differently to various protocols evaluated, and that to make substantial progress in non-surgical AI further exploration into biological and management interactions will be necessary.