Development of a GnRH-PGF2α Based Synchronization and Superstimulation Protocol for Fixed-Time Mating in Llama Embryo Donors.

Enzo German Zampini,Maria Graciela Chaves,Luciana Cabido,Marcelo Horacio Miragaya,Deborah Margarita Neild,Fernanda Gabriela Fumuso,Virginia Luz Trasorras,Maria Fernanda Veiga

doi:10.3389/fvets.2020.595889

Enzo German Zampini, Maria Graciela Chaves + Show 6 more

Open Access

https://doi.org/10.3389/fvets.2020.595889

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Abstract

The aim of the present study was to evaluate the application of a GnRH-PGF2α based synchronization and superstimulation protocol for fixed-time natural mating in llama embryo donors. All females (n = 8) received 8 μg IM of GnRH analog (GnRHa; buserelin) on day 0, regardless of follicular status. After eight days, another GnRHa dose was administered followed by 250 μg IM PGF2α (cloprostenol). A dose of 1000 IU IM of equine chorionic gonadotrophin (eCG) was applied on day 12 and a new dose of PGF2α was administered on day 13. All embryo donors were mated with a male of proven fertility followed by a GnRHa dose on day 18. 24 h later, mating was repeated with a different male. Transcervical uterine flushing for embryo recovery was carried out on all females on day 26. Recipient females received one dose of GnRHa (day 0) two days after the first mating of embryo donor females. A 75% (6/8) of embryo donors responded to the superstimulation treatment with a range of 2 to 5 corpus luteums (CLs) on embryo recovery day. A total of 24 CLs were registered, with a mean of 4 ± 0.9 CLs per female. Embryo recovery rate was 66.7% (16/24), with a range of 0 to 4 embryos and a mean of 2.7 ± 1.5 embryos per female. Regarding quality of the recovered embryos, 56.2% were grade I, 6.2% were grade II and 37.5% were grade V (untransferable; arrested morulae). Grade I and II embryos (n = 10) were transcervically transferred into recipient females (n = 10) six days after inducing their ovulation. At 24 days after embryo transfer (ET), a 50% pregnancy rate was registered. In conclusion, a group of llama embryo donors can be synchronized and superstimulated using a fixed-time mating protocol based on GnRHa, PGF2α, and eCG without the necessity of using ultrasonography in the field.

Highlights

Breeding llamas (Lama glama) is an economically relevant animal husbandry activity for a large sector of the high-altitude populations of South America, as the by-products of meat, fiber and manure are all put to use
The objective of this study was to evaluate the efficiency of a simple, fixed-time synchronizationovarian superstimulation protocol in llamas, for use in an embryo transfer program, that does not depend on ultrasonography and is based on the administration of two doses of a GnRH analog, prostaglandin and equine chorionic gonadotrophin
Donor females were evaluated by transrectal ultrasonography before carrying out the uterine flushing on day 26

Summary

Introduction

Breeding llamas (Lama glama) is an economically relevant animal husbandry activity for a large sector of the high-altitude populations of South America, as the by-products of meat, fiber and manure are all put to use. The mean annual fertility (birthing rate) in alpacas (Vicugna pacos) and llamas in South America can be as low as 45% [3]. This low reproductive performance has different causes, for example, a late puberty [4], short reproductive seasonality in their natural habitat [5], long gestations (335 to 360 days) and birthing only one offspring at a time [6,7,8]

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