Phenotypic study on total and partial lifetime traits for dairy ewes.

Area of Science:

• Animal Science
• Quantitative Genetics
• Reproductive Biology

Background:

• Phenotypic relationships between productive, reproductive, and lifespan traits are crucial for efficient sheep breeding.
• Understanding these relationships in Spanish Churra ewes can optimize flock management and genetic selection.

Purpose of the Study:

• To determine the strength of phenotypic relationships between productive, reproductive, and lifespan traits in Spanish Churra ewes.
• To assess the predictive value of early-life traits for overall ewe performance and longevity.

Main Methods:

• Analysis of 36,396 lactations from 7935 Spanish Churra ewes across 23 flocks.
• Statistical modeling including fixed effects of flock, birth year, and season, with milk production level added for lifespan traits.
• Calculation of various lifespan, productive, and reproductive traits, including per-day measures.

Main Results:

• Strong positive correlations (0.75-0.95) were observed between lifespan and productive traits.
• Milk production level significantly explained variation in lifespan traits (average 14.91% variance).
• Early-life productive and reproductive traits showed moderate to high correlations with lifetime performance.

Conclusions:

• Lifespan and productive traits in Churra ewes are strongly interrelated.
• Early-life performance indicators can effectively predict long-term productivity and longevity.
• Utilizing these relationships aids in early identification of superior ewes for breeding programs.