Optimization of the feed intake test period in sheep production

Measuring feed efficiency (FE) in sheep is costly. Reducing the duration of dry matter intake (DMI) tests as a component of FE may lower expenses, while allowing for more animals to be assessed annually. This study analyzed a dataset of 46 016 DMI values from 1064 animals (796 ewes and 268 rams) in nine contemporary groups to explore the feasibility of shortening the DMI measurement periods from the 38-day standard DMI test period to accurately predict FE. We assessed the accuracy and precision of shortened test periods using Pearson and Spearman correlations, standardized regression coefficients (β), coefficient of determination (R²), and concordance correlation coefficients (CCC). Results indicated that DMI test period can be reduced from the 38 days standard test days to 22, 24, and 25 days in ewes, rams and across gender, respectively, while maintaining Pearson and Spearman correlations of 95%. Other statistics revealed that the DMI test period in ewes could be reduced from 38 to 22 days with a β of 0.89, R² of 0.94, and CCC at 95%, to 24 days for rams with β of 0.96, R² of 0.94, and CCC at 0.95, and to 25 days across gender with β of 0.97, R² of 0.96, and CCC at 0.97. In conclusion, DMI test periods can be shortened without compromising data integrity, enhancing phenotypic evaluations in sheep.