Fetherstone Nicola, Hely Fiona S, McHugh Noirín, McGovern Fiona M, Amer Peter R
Teagasc, Animal and Grassland Research and Innovation Centre, Mellows Campus, Athenry, Co. Galway, Ireland.
School of Agriculture and Food Science, University College Dublin, Belfield, Dublin 4, Ireland.
Genet Sel Evol. 2021 Jan 6;53(1):5. doi: 10.1186/s12711-020-00594-y.
Importation of foreign genetics is a widely used genetic improvement strategy. However, even if the foreign genetic merit is currently greater than the domestic genetic merit, differences in foreign and domestic trends mean that the long-term competitiveness of an importation strategy cannot be guaranteed. Gene flow models are used to quantify the impact that a specific subpopulation, such as foreign genetics, can have over time on the genetic or economic benefit of a domestic industry.
We used a deterministic recursive gene flow model to predict the commercial performance of lambs born across various subpopulations. Numerous breeding strategies were evaluated by varying market share, proportions of rams selected for mating, genetic trend, superiority of foreign genetics over domestic genetics and frequency of importation. Specifically, an Ireland-New Zealand case study was simulated to quantify the potential gain that could be made by using foreign sire contributions (New Zealand) in a domestic sheep industry (Ireland).
Genetic and economic gains were generated from alternative breeding strategies. The 'base scenario' (i.e. representing the current industry) predicted an average genetic merit value of €2.51 for lambs born and an annualised cumulative benefit of €45 million (m) after 20 years. Maximum genetic (€9.45 for lambs born) and economic (annualised cumulative benefit of €180 m after 20 years) benefits were achieved by implementing the 'PRO-intense-market scenario' which involved shifting market share away from conservative domestic breeders and reducing the proportion of rams that were selected for mating by progressive domestic breeders from the top 40% to the top 20%, without the use of any foreign genetics. The 'PROFOR scenario', which considered the use of foreign and progressive domestic genetics, predicted an average genetic merit value of €7.37 for lambs born and an annualised cumulative benefit of €144 m, after 20 years.
Our results demonstrate that there is opportunity for a domestic industry to increase industry benefits without the use of foreign genetics but through an attempt to shift the market share away from conservative domestic breeders towards progressive domestic breeders. However, the importation and use of progressive foreign genetics may be an effective method to trigger a change in behaviour of conservative domestic breeders towards the use of progressive genetics.
引入外来基因是一种广泛应用的遗传改良策略。然而，即便当前外来基因的遗传优势高于国内基因，但国内外发展趋势的差异意味着无法确保引入策略具有长期竞争力。基因流动模型用于量化特定亚群（如外来基因）随着时间推移对国内产业的遗传或经济效益可能产生的影响。
我们使用确定性递归基因流动模型来预测不同亚群所产羔羊的商业性能。通过改变市场份额、选作种用公羊的比例、遗传趋势、外来基因相对于国内基因的优势以及引入频率，评估了众多育种策略。具体而言，模拟了爱尔兰 - 新西兰的案例研究，以量化在国内绵羊产业（爱尔兰）中使用外来父本贡献（新西兰）可能带来的潜在收益。
替代育种策略产生了遗传和经济效益。“基础情景”（即代表当前产业）预测所产羔羊的平均遗传价值为2.51欧元，20年后的年化累计收益为4500万欧元。通过实施“PRO - 高强度 - 市场情景”实现了最大遗传（所产羔羊为9.45欧元）和经济（20年后年化累计收益为1.8亿欧元）效益，该情景包括将市场份额从保守的国内育种者手中转移，并将进步的国内育种者选作种用公羊的比例从顶部的40%降至20%，且不使用任何外来基因。考虑使用外来和进步的国内基因的“PROFOR情景”预测，20年后所产羔羊的平均遗传价值为7.37欧元，年化累计收益为1.44亿欧元。
我们的结果表明，国内产业有机会在不使用外来基因的情况下，通过尝试将市场份额从保守的国内育种者转向进步的国内育种者来提高产业效益。然而，引入和使用进步的外来基因可能是促使保守的国内育种者改变行为以使用进步基因的有效方法。
