Growth and carcass traits of three Portuguese autochthonous chicken breeds: Amarela, Preta Lusitânica and Pedrês Portuguesa

Abstract

The purpose of this study was to estimate the growth curve parameters and carcass traits yields of three Portuguese autochthonous chicken breeds, Amarela (AM), Preta Lusitânica (PL) and Pedrês Portuguesa (PP). Birds (198) were individually weighed at pre-established time intervals (6682 records) and the study period lasted 30 months. The growth data were fitted to a mixed nonlinear model based on the Gompertz growth function. Fixed effects were breed, sex, lot, temperature and photoperiod. The adult weight estimated for males (females) were 2851.3 (1951.6) g for AM, 3047.5 (2147.7) g for PL, and 3243.7 (2344.0) g for PP, respectively. The males (females) estimated maximum daily growth were 22.7 (18.1) g at 77 (69) days for AM, 20.7 (17.5) g at 79 (72) days for PL, and 18.1 (16.3) g at 82 (74) days for PP, respectively. Within breed the males were heavier than females at 365 days but with lower maturity rates. Yields of carcass and noble meat pieces were evaluated on data collected from 10 males of each breed, sacrificed at 240 days. Traditionally, these breeds are commercialised whole and again the PP had the heaviest carcass with the highest yield. Growth of these autochthonous breeds after 240 days was minimal and may justify the decrease of the traditional slaughter age of approximately one year, in order to increase profitability. Establishing special market niches will also be a valuable complement for the rural economy of Portugal and an important contribution to the conservation of this genetic heritage.

Keywords

• Autochthonous chicken breeds, Carcass yield, Gompertz growth function