Ewe fertility in the STAR accelerated lambing system

Area of Science:

• Animal Science
• Reproductive Biology
• Sheep Production

Background:

• Accelerated lambing systems aim to increase flock reproductive efficiency.
• Understanding factors influencing ewe fertility is crucial for optimizing breeding programs.
• Environmental and physiological factors can significantly impact sheep reproductive success.

Purpose of the Study:

• To evaluate the effects of ewe age, season, and time since lambing on fertility in an accelerated lambing system.
• To identify predictable patterns in ewe fertility throughout the year.
• To develop a model for predicting fertility based on key influencing factors.

Main Methods:

• Analysis of breeding records from 1,084 Dorset ewes in the STAR accelerated lambing system.
• Evaluation of fertility across five distinct 30-day breeding and lambing periods annually.
• Statistical modeling (mixed GLM) to assess the combined impact of season, ewe age, and postpartum interval.

Main Results:

• Ewe fertility exhibited cyclic and predictable variations throughout the year.
• Matings during typical breeding seasons (August, October, January) showed higher fertility than those in March and June.
• Fertility was influenced by ewe age and time since last lambing, with interactions between these factors and season.

Conclusions:

• Seasonal effects, ewe age, and postpartum interval are critical determinants of fertility in accelerated lambing.
• Predictive models incorporating these factors can aid in managing and optimizing breeding strategies.
• The findings provide valuable insights for enhancing reproductive efficiency in commercial sheep operations.