Repeatability and relationship with field mating performance of a serving capacity pen test in rams

Area of Science:

• Animal Science
• Reproductive Biology
• Veterinary Medicine

Background:

• Serving capacity (SC) is crucial for ram reproductive efficiency.
• Accurate assessment of SC is vital for selective breeding and improving flock fertility.
• Existing methods for SC evaluation require validation for reliability and field correlation.

Purpose of the Study:

• To assess the repeatability of the Laborde SC pen test.
• To evaluate the correlation between Laborde SC test results and ram field performance.
• To determine if high SC rams improve ewe pregnancy rates in commercial settings.

Main Methods:

• The Laborde SC test involved exposing individual rams to two restrained ewes for 40 minutes.
• SC was measured multiple times within and across breeding seasons (1994, 1995).
• Field performance was evaluated on two commercial farms using synchronized ewes served by high or low SC rams.

Main Results:

• The Laborde SC test demonstrated high repeatability within and between breeding seasons (p<0.05).
• Ewes served by high SC rams exhibited significantly higher pregnancy rates compared to those served by low SC rams (p<0.05).
• Results confirmed a positive correlation between SC pen test scores and field reproductive success.

Conclusions:

• The Laborde SC pen test is a reliable tool for evaluating ram serving capacity.
• Selecting rams with high SC, as identified by the Laborde test, can enhance field reproductive performance and flock fertility.