Breed assignment test in four Italian beef cattle breeds.

Area of Science:

• Animal Genetics
• Molecular Ecology
• Livestock Breeding

Background:

• Breed identification is essential for livestock product authenticity and quality assurance.
• Microsatellite markers are widely used for population genetics studies.

Purpose of the Study:

• To evaluate methods for assigning individuals to their native Italian beef breed of origin.
• To assess the effectiveness of different microsatellite marker sets for breed identification.

Main Methods:

• Testing 21 microsatellite markers across four Italian beef breeds: Chianina, Marchigiana, Romagnola, and Piemontese.
• Comparing maximum likelihood and Bayesian statistical approaches for individual assignment.
• Evaluating marker sets based on gene diversity and F(ST) estimates.

Main Results:

• The Bayesian method achieved approximately 90% correct assignment rate with just six microsatellites.
• Marker sets with higher gene diversity performed better in breed identification.
• Low genetic differentiation (F(ST)=0.049) among breeds limited overall assignment accuracy, with only 52.5% correctly allocated at a 90% probability threshold.

Conclusions:

• The Bayesian method is superior for breed assignment in these Italian beef cattle populations.
• Future research should focus on markers with high gene diversity and private alleles.
• Accurate breed identification is vital for livestock product certification and traceability.