Quantitative Trait Loci Mapping for Lameness Associated Phenotypes in Holstein-Friesian Dairy Cattle.

Enrique Sánchez-Molano,Georgios Oikonomou,Veysel Bay,Robert F Smith,Georgios Banos

doi:10.3389/fgene.2019.00926

Abstract

Lameness represents a significant challenge for the dairy cattle industry, resulting in economic losses and reduced animal health and welfare. The existence of underlying genomic variation for lameness associated traits has the potential to improve selection strategies by using genomic markers. Therefore, the aim of this study was to identify genomic regions and potential candidate genes associated with lameness traits. Lameness related lesions and digital cushion thickness were studied using records collected by our research team, farm records, and a combination of both. Genome-wide analyses were performed to identify significant genomic effects, and a combination of single SNP association analysis and regional heritability mapping was used to identify associated genomic regions. Significant genomic effects were identified for several lameness related traits: Two genomic regions were identified on chromosome 3 associated with digital dermatitis and interdigital hyperplasia, one genomic region on chromosome 23 associated with interdigital hyperplasia, and one genomic region on chromosome 2 associated with sole haemorrhage. Candidate genes in those regions are mainly related to immune response and fibroblast proliferation. Quantitative trait loci (QTL) identified in this study could enlighten the understanding of lameness pathogenesis, providing an opportunity to improve health and welfare in dairy cattle with the addition of these regions into selection programs.

Highlights

Lameness is a complex trait defined as an abnormal stance or gait of the animal that results from disorders of the locomotor system
Susceptibility to certain non-infectious foot lesions is associated with morphological hoof traits such as the thickness of the digital cushion, a complex, force dissipating, subcutaneous tissue located under the distal phalanx (Bicalho et al, 2009)
The first seven principal components accounted for about 10% of the total variance, with the first three components

Summary

Introduction

Lameness is a complex trait defined as an abnormal stance or gait of the animal that results from disorders of the locomotor system. Lameness is one of the most important health conditions together with impaired fertility and mastitis (Green et al, 2002; Buitenhuis et al, 2007; Cha et al, 2010), and causes important economic losses and reduced animal health and welfare (Huxley, 2013). Many lameness cases are associated to various infectious and non-infectious diseases (Green et al, 2002; Van Der Waaij et al, 2005; Bicalho and Oikonomou, 2013), resulting in painful foot lesions such as sole ulcers, white line lesions, sole haemorrhages, interdigital hyperplasia, and others. Previous studies have shown that both animal genetic and management factors contribute to the QTL for Dairy Cattle Lameness development of these diseases (Olmos et al, 2009; Van Der Linde et al, 2010; Swalve et al, 2014). Susceptibility to certain non-infectious foot lesions is associated with morphological hoof traits such as the thickness of the digital cushion, a complex, force dissipating, subcutaneous tissue located under the distal phalanx (Bicalho et al, 2009)

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Results

Conclusion