The combined use of embryos and semen for cryogenic conservation of mammalian livestock genetic resources

Paul J Boettcher,Alessandra Stella,Gustavo Gandini,Flavia Pizzi

doi:10.1186/1297-9686-37-7-657

Abstract

The objective of this empirical simulation study was to evaluate the use of a combination of semen and embryos in the creation of gene banks for reconstruction of an extinct breed. Such an approach was compared for banks with varying proportions of embryos on the basis of the amount of the material to be stored, time for reconstruction, maintenance of genetic variability, and probability of failure during reconstruction. Four types of populations were simulated, based on reproductive rate: single offspring, twinning, enhanced reproduction, and litter bearing. Reconstruction was simulated for banks consisting of different combinations of semen and reduced numbers of embryos (expressed as a percentage of the material needed for a bank containing exclusively embryos and ranging from 10 to 90%). The use of a combination of semen and embryos increased the number of insemination cycles needed for reconstruction and the level of genetic relatedness in the reconstructed population. The risk for extinction was unacceptably high when a very low proportion of embryos (< 20%) was used. However, combining semen with embryos could decrease costs, allowing for the conservation of more breeds, and specific strategies for semen use could decrease the level of relationships in the reconstructed breed.

Highlights

In 1992 the Convention on Biological Diversity advised ex situ conservation as an essential activity complementary to in situ conservation of farm animal genetic resources
The amount of genetic material to be stored is a function of the intended future use of the material, which may include creation of new lines and breeds, supporting populations conserved in vivo, and breed reconstruction, with the latter generally being considered as the maximum guarantee against risk of breed loss
An overview of practical rules for collecting semen and embryos and of the organisational aspects of cryobanking setting were presented in a Workshop organised by the European Regional Focal Point (ERFP) for Animal Genetic Resources of the FAO [14]

Summary

Introduction

In 1992 the Convention on Biological Diversity advised ex situ conservation as an essential activity complementary to in situ conservation of farm animal genetic resources. Require severe culling of the population, has underlined the importance of having cryopreserved genetic material to allow for breed reconstruction. Semen and embryos have been both proposed as materials for cryopreservation of animal genetic resources [3, 4]. The amount of genetic material to be stored is a function of (among other factors) the intended future use of the material, which may include creation of new lines and breeds, supporting populations conserved in vivo, and breed reconstruction, with the latter generally being considered as the maximum guarantee against risk of breed loss. An overview of practical rules for collecting semen and embryos and of the organisational aspects of cryobanking setting were presented in a Workshop organised by the European Regional Focal Point (ERFP) for Animal Genetic Resources of the FAO [14]

Objectives

Methods

Results

Conclusion