A genetic study of estrus symptoms at puberty and their relationship to growth and leanness in gilts.

Puberty traits of 740 Yorkshire gilts from a selection experiment were analyzed. Heritabilities were estimated to be .32 for pubertal age, .23 for length of proestrus, .16 for length of standing estrus, .29 for ability to show standing reflex, and .24 for intensity of vulvar symptoms. Genetic correlations between length of proestrus, intensity of vulvar symptoms, and ability to show standing reflex were positive. There seemed to be a negative genetic correlation between percentage of lean and intensity of vulvar symptoms. There were negative genetic correlations between growth rate and length of standing estrus, and between growth rate and ability to show standing reflex.