Evaluation of slower-growing broiler genotypes grown with and without outdoor access: growth performance and carcass yield

Abstract

Consumer interest in organic and free-range poultry production is growing. An experiment was conducted to assess the impact of genotype and outdoor access on growth rate and carcass yield. One slow-growing genotype (S), 2 medium-growing genotypes (M1 and M2), and a commercial fast-growing genotype (F) were raised (straight-run) for 81, 67, and 53 d, respectively. The placement date was staggered in order to achieve a similar final body weight and each genotype was processed on the same day. Each genotype was assigned to 3 pens of 24 birds each and raised in indoor floor pens in a curtain-sided house with ventilation fans; the S and F genotypes were also assigned to 2 floor pens with outdoor access (during daylight hours) containing 36 birds each. All birds were provided with the same starter, grower, and finisher feeds, and birds were commercially processed. Weight gain was similar (P > 0.05) among genotypes, but males gained more weight (P < 0.05) than females. The S and F genotypes had the highest and lowest (P < 0.05) feed intakes and, consequently, the lowest and highest (P < 0.05) feed efficiencies, respectively. The F genotype had the greatest (P < 0.05) breast yield (%) and the lowest (P < 0.05) wing yield (%). The S genotype exhibited the lowest (P < 0.05) breast yield (%) and the greatest leg quarter yield (%). Birds given outdoor access had greater (P < 0.05) bone strength in the tibia, and the F genotype had highest (P < 0.05) bone strength. These data indicate that substantial growth performance and yield differences exist among genotypes in alternative poultry systems.

The effects of access to pasture on growth performance, behavioural patterns, some blood parameters and carcass yield of a slow-growing broiler genotype

“…Higher percentage of breast and thigh yields may be explained by effects of the outdoor rearing system on activity (Ponte et al 2008b) and locomotor activity (Castellini et al 2002b;Wang et al 2009). In contrast, in our results it was concluded that outdoor access did not affect carcass and part yields (Fanatico et al 2005;Wang et al 2009;Jiang et al 2011). Besides, in the outdoor group as a result of activity, abdominal fat was found to be lower than the indoor group.…”

“…Broilers were individually weighed to determine slaughter weight and then were slaughtered in a processing plant of the university farm. After slaughter, broilers were scalded at 53°C for 120 s prior to plucking (Fanatico et al 2005), followed by manual evisceration. Carcasses were prechilled in water at 12°C for 15 min and chilled at 1°C for 3 h and then carcasses were weighed.…”

Comparison of qualitative and quantitative properties of the wings, necks and offal of chicken broilers from organic and conventional production systems

“…In contrast, the wings and necks of OC yielded more than CC, which is in agreement with the results found by Fanatico et al (2005) indicating that birds with slow-and medium-growing genotypes had higher wing yields than chickens with fast-growing genotypes. The increase in breast yield, which is the result of fast-growing genotype selection, leads to a decreased yield of other chicken parts.…”

Effect of Faba BeanVicia FabaVar.Minor) Inclusion in Starter and Growing Diet on Performance, Carcass and Meat Characteristics of Organic Slow-Growing Chickens

“…Organic diets should be formulated with the organic ingredients without synthetic forms of amino acids and GMO ingredients; thus, it is crucial to formulate feed with lower quantity of soybean, which has a high risk of GMO contamination (Hanson et al, 2004), and use genotypes having lower protein and amino acids requirements (Leclercq et al, 1993;Pesti et al, 1994;Rosa et al, 2001). Slow-growing birds meet such request and are recommended for the better adaptation to the outdoor environment and to a longer rearing period (Castellini et al, 2002;Fanatico et al, 2005). In Mediterranean countries the most interesting legume alternative to soybean is the faba bean (Vicia Faba var.…”