Genetic analysis of maternal behavior and its effect on lamb survival

Abstract: Improvement of lamb survival rates is an important topic for production and welfare in the sheep industry. Maternal behavior affects lamb survival and vigor during the neonatal period. A measurement used in the literature for maternal behavior is MBS, which measures the distance between ewe and lamb during handling of the lamb. MBS displays low to moderate heritability and repeatability. Genetic correlations with litter survival are considered to be low. Small genetic improvement for lamb survival is expected but the advance would be slow. The aim of this current review was to investigate the genetic value of incorporating maternal behavior as an indirect selection trait for lamb survival in breeding programs. With the low genetic parameters found it is suggested that selection for maternal behavior to improve lamb survival would have slow genetic progress. Other correlated traits might be more efficient to improve lamb survival. The evaluation of differences between breeds in this review indicates that more intensively bred breeds have lost more maternal ability than those who have been extensively bred. This could imply that our current, intense breeding for production traits without including maternal behavior is resulting in a decline of ewes expressing good maternal care. If further research can strengthen this theory, maternal behavior should be included in breeding programs for sheep.