慢性进行性淋巴水肿(CPL)是Rhenish德国旱马中普遍存在的进行性疾病。我们的后续研究的目的是使用基于系谱和基因组关系的矩阵评估Rhenish德国旱马中这种疾病的遗传力。我们采用线性和阈值动物模型。模型包括随机动物效应和育种协会效应,外套颜色,性别,和性别中的年龄,和农场相关的因素,关于CPL分数。此外,当马匹年龄在1-15岁以下时,我们在假设数据审查的模型中估计了遗传力。在基于系谱关系矩阵的阈值和线性动物模型中,所有年龄段的CPL得分的遗传力分别为0.595±0.131和0.482±0.105。分别。将数据限制在最小年龄的马匹上,或考虑年轻动物的删失数据,表明CPL得分的遗传力增加了0.788±0.168(阈值模型)和0.752±0.153(线性模型)。7-8岁。包括基因组关系矩阵在内的分析产生了非常相似的估计,但标准误差小于基于谱系的分析。CPL患病率(CPL-bin-score)和受影响肢体数量(CPL-bin-sum)的阈值模型的遗传率分别为0.176-0.189±0.061-0.064和0.375-0.433±0.164-0.170。我们能够显示CPL评分与大炮骨围之间的中度到高度正的遗传相关性(0.529-0.825),枯萎处的高度(0.338-0.555),和皮褶厚度(0.241-0.517)。使用CPL得分的二分性状和基因组关系矩阵分别导致0.868、0.793和0.784的相应估计。这项研究表明,加性遗传变异影响Rhenish德国旱马慢性进行性淋巴水肿的表达非常重要。因此,有必要进行进一步的研究,以在小的育种群体中实施育种计划,利用动物之间累加遗传差异的潜力来降低这种无法治愈的疾病的患病率和病变的严重程度。
Chronic progressive lymphedema (CPL) is a prevalent and progressive disease in Rhenish German draught horses. The objective of our follow-up study was to evaluate the heritability of this disease in Rhenish German draught horses using pedigree-based and genomic relationship matrices. We employed linear and threshold animal models. Models included the random animal effect and effects of breeding association, coat colour, sex, and age within sex, and farm-related factors, on CPL scores. In addition, we estimated heritabilities in models assuming
censoring for data when horses were below an age of 1-15 years. The heritabilities of CPL scores across all ages were 0.595 ± 0.131 and 0.482 ± 0.105 in the threshold and linear animal model with pedigree-based relationship matrices, respectively. The restriction of data to horses with a minimum age at examination or accounting for censored data in younger animals showed an increase in heritabilities of CPL scores up to 0.788 ± 0.168 (threshold model) and 0.752 ± 0.153 (linear model) at an age of 7-8 years. Analyses including genomic relationship matrices yielded very similar estimates, but with smaller standard errors than pedigree-based analyses. Heritabilities in threshold models for CPL prevalence (CPL-bin-score) and the number of affected limbs (CPL-bin-sum) were 0.176-0.189 ± 0.061-0.064 and 0.375-0.433 ± 0.164-0.170, respectively. We were able to show moderately to highly positive genetic correlations between the CPL score and cannon bone circumference (0.529-0.825), height at withers (0.338-0.555), and skinfold thickness (0.241-0.517). Using the dichotomous trait for the CPL score and the genomic relationship matrix resulted in corresponding estimates of 0.868, 0.793, and 0.784, respectively. This study showed the great importance of additive genetic variation influencing the expression of chronic progressive lymphedema in Rhenish German draught horses. Therefore, further research is warranted to implement breeding programmes in a small breeding population that exploit the potential of additive genetic differences among animals for reducing the prevalence and severity of lesions of this incurable disease.