《meat-type chickens》.pdfVIP

Aggrey et al. Genetics Selection Evolution 2010, 42:25 Ge n e t i c s /content/42/1/25 Se l e c t i o n Evolution R E S E A R C H Open Access Research Genetic properties of feed efficiency parameters in meat-type chickens 1,2 1 2 3 Samuel E Aggrey* , Arthur B Karnuah , Bram Sebastian and Nicholas B Anthony Abstract Background: Feed cost constitutes about 70% of the cost of raising broilers, but the efficiency of feed utilization has not kept up the growth potential of todays broilers. Improvement in feed efficiency would reduce the amount of feed required for growth, the production cost and the amount of nitrogenous waste. We studied residual feed intake (RFI) and feed conversion ratio (FCR) over two age periods to delineate their genetic inter-relationships. Methods: We used an animal model combined with Gibb sampling to estimate genetic parameters in a pedigreed random mating broiler control population. Results: Heritability of RFI and FCR was 0.42-0.45. Thus selection on RFI was expected to improve feed efficiency and subsequently reduce feed intake (FI). Whereas the genetic correlation between RFI and body weight gain (BWG) at days 28-35 was moderately positive, it was negligible at days 35-42. Therefore, the timing of selection for RFI will influence the expected response. Selection for improved RFI at days 28-35 will reduce FI, but also increase growth rate. However, selection for improv