Selection for meat production in poultry has significantly increased body weight due to its moderate to high heritability, large populations, and efficient breeding programs, resulting in high throughput production of meat. Nevertheless, there is a genetic antagonism between growth and reproduction traits, causing a decrease in fitness for highly selected populations (Silva et al., 2013a, Silva et al., 2013b).

The genetic relationship between male and female reproduction traits is well-known in mammals but results in poultry are conflicting (Kaiser and Ellegren, 2006). It is supposed that the underlying physiological mechanism is the same, and selection for male reproduction traits can result in a response in females and vice versa.

The cloacal gland is associated with male fertility, testes weight, mate frequency, foam discharge, and plasma testosterone (Biswas et al., 2007). However, information about the genetic effects of selection based on cloacal gland size on female reproduction is limited.

For better planning breeding programs, an understanding of genetic parameters for reproduction traits is required to optimize production systems efficiency for breeding or egg markets.

This study aimed to estimate heritabilities, genetic, and residual correlations among 4-week body weight, cloacal gland area, reproductive organs weights and age at sexual maturity both for males and females, in meat-type quail.