Effects of selection for exponential growth rate at different ages on reproduction in chickens

Authors: Kerr, C.L.; Hammerstedt, R.H.; Barbato, G.F.

Source: Avian and Poultry Biology Reviews, Volume 12, Number 3, August 2001 , pp. 127-136(10)

Publisher: Science Reviews 2000 Ltd

Buy & download fulltext article:

Price: $29.00 plus tax (Refund Policy)

Abstract:

This study evaluated the correlated responses between selection for early developmental growth (essential for commercial acceptance and profitability of meat-type chickens) and reproductive traits (essential to chick production). A double, divergent selection experiment for growth rate to different ages suggests that traditional concepts of the negative correlation between growth and reproduction are due to cumulative genetic effects influencing growth during the linear portion of the growth curve, not ``growth'' per se. Eight generations of divergent selection for exponential growth rate (EGR) from 0 to 14 days (EGR₁₄) of age or 0 to 42 days of age (EGR₄₂) resulted in a four-fold difference in EGR₁₄ and an eight-fold difference in EGR₄₂ between the divergently selected lines. Correlated traits contributing to reproduction included: percentage hen-day egg production (HDP), fertility and hatchability, and both age (AFE) and weight (WFE) at first egg. Hens from the line selected for fast EGR₄₂ (42H line)were significantly heavier than those from the line selected for slow EGR₄₂ (42L line) and came into production 31days earlier. Fertility diminished rapidly in the line selected for slow EGR₁₄ while HDP was unchanged. The AFE and WFE of both EGR₁₄ selected lines were not different. Further, the average values for AFE, WFE of the EGR₁₄ lines were intermediate to the mean values for the EGR₄₂ lines, suggesting a critical period of development between 14 and 42 days of age influencing these traits and the onset of sexual maturation.

Keywords: genetics; selection; growth; sexual maturity; fertility

Document Type: Research article

DOI: http://dx.doi.org/10.3184/147020601783698503

Affiliations: 1: Department Poultry Science, The Pennsylvania State University, PA 16802, USA

Publication date: 2001-08-28

More about this publication?