Genetic Evaluation Division, IT Solutions for Animal Production (vit), Verden, Germany.
Institute for Animal Breeding and Genetics, University of Veterinary Medicine Hannover (Foundation), Hanover, Germany.
PLoS One. 2022 Jul 28;17(7):e0267975. doi: 10.1371/journal.pone.0267975. eCollection 2022.
Awareness of breeders of Warmblood Fragile Foal Syndrome (WFFS) increased after a widely discussed case in the USA in 2018. The hereditary connective tissue disorder, first described by a US research group in 2011 and for which a commercial genetic test exists since 2013, is caused by a point mutation in the PLOD1 gene, inherited autosomal recessively. Extension of molecular genetic testing and reporting of test results of organized horse breeders to their studbooks implies new opportunities for analyses. In Germany, data are centrally accessible through the integrated equine data base allowing comprehensive and population-wide investigation of the role of WFFS. The objective of this study was statistical testing for associations between WFFS and reproductive performance of German riding horses and quantifying possible differences between WFFS carriers and non-carriers, also in respect of performance traits. For this purpose, covering data from 2008 to 2020 were provided by ten German studbooks, so almost 400,000 coverings and resulting foaling rates were available for multiple analyses of variance with general and mixed linear models using procedures GLM, MIXED and HPMIXED of SAS software (version 9.2). Published breeding values of stallions were used for respective comparisons of riding horse performance. Assuming a WFFS carrier frequency of 9.5-15.0% in Warmblood horses, Hardy Weinberg principle implied an expected difference of 2.4-3.7% in the foaling rates of carrier and non-carrier stallions. Our results provided statistical evidence of detrimental effects of WFFS on the reproductive performance of Warmblood horses with about 2.7% lower average foaling rate in carriers of the mutant allele than in WFFS free sires, if mated to an average mare population. Indications of favorable dressage performance of WFFS carriers were found. Reported WFFS cases indicate only the tip of the iceberg and assessing the impact of WFFS on reproduction requires consideration of premature foal losses.
温血马易碎驹综合征（WFFS）的饲养员在 2018 年美国一起广泛讨论的病例后，对此疾病的认识有所提高。这种遗传性结缔组织疾病，最初是由一个美国研究小组于 2011 年首次描述，并且自 2013 年以来就有商业化的基因测试，是由 PLOD1 基因突变引起的，呈常染色体隐性遗传。对有组织的马饲养员的分子遗传测试和测试结果的扩展报告扩展到他们的血统书中，意味着有新的机会进行分析。在德国，通过集成的马数据库，可以集中访问数据，从而对德国骑乘马的 WFFS 作用进行全面和全人群调查。本研究的目的是对德国骑乘马的 WFFS 与繁殖性能之间的关联进行统计检验，并量化 WFFS 携带者和非携带者之间的差异，包括在性能特征方面的差异。为此，十个德国种马协会提供了 2008 年至 2020 年的数据，因此，使用 SAS 软件（版本 9.2）的 GLM、MIXED 和 HPMIXED 程序进行的多个方差分析提供了近 40 万次配种和产驹率，可用于一般和混合线性模型。使用公布的种马育种值进行了相应的骑乘马性能比较。假设温血马中 WFFS 携带者的频率为 9.5-15.0%，则哈迪-温伯格原理表明，携带者和非携带者种马的产驹率预期会有 2.4-3.7%的差异。我们的结果提供了 WFFS 对温血马繁殖性能的不利影响的统计证据，如果突变等位基因的携带者与平均母马种群交配，携带者的平均产驹率比 WFFS 自由的种马低约 2.7%。发现了 WFFS 携带者在盛装舞步表现方面的有利迹象。报告的 WFFS 病例仅表明冰山一角，评估 WFFS 对繁殖的影响需要考虑早产驹的损失。
