Genome-Wide Association Study Reveals Single Nucleotide Polymorphisms Associated with Tail Length and Tail Kinks in...

Area of Science:

• Animal Genetics
• Animal Welfare Science
• Swine Production

Background:

• Tail docking in pigs is a common but controversial practice to prevent tail biting.
• Genetic selection for shorter tails is proposed as an alternative to tail docking.
• Previous studies indicate a genetic basis and heritability for tail length in pigs.

Purpose of the Study:

• Identify genetic markers associated with tail length in pigs.
• Determine candidate genes influencing tail length.
• Evaluate the potential of genetic selection for tail length as an alternative to tail docking.

Main Methods:

• Phenotyped and genotyped 140 piglets at 3 days of age.
• Conducted a genome-wide association study (GWAS) to identify single nucleotide polymorphisms (SNPs).
• Analyzed the association between identified SNPs, relative tail length, and tail malformations.

Main Results:

• Seven SNPs were mapped to pig chromosomes 1, 2, 6, 11, and 15.
• Two linked SNPs on chromosome 2 were associated with a functional amino acid exchange.
• SNPs showed small effects on relative tail length (up to 16.5%) and were linked to tail kinks.

Conclusions:

• Genetic markers for tail length in pigs have limited effect size.
• Selection for shorter tails is associated with undesirable tail malformations (kinks).
• The findings argue against the applicability of selecting for shorter tails to avoid tail docking and tail biting.