Variation of meat-type chickens in relation to genotypes and age of slaughter on carcass indices.

The experiment was conducted to compare the various carcass characteristics between two broiler strains. A total bird of 150 day-old chick of two commercial broiler strains (Marshall and Cobb, 75 each) were raised and at the end of 4, 6 and 8 weeks, 20 birds/strain; 40 birds/week, making a total of 120 birds were randomly selected from both strains for carcass analysis. The birds were starved of feed overnight and individually weighed to obtain starved live body weight. The birds were stunned and bled by severing the blood vessels and the nerve trunks at the roof of the mouth with a sticking knife. Thereafter, the birds were scalded, deplumed manually and eviscerated through a slit made between the end of the keel bone and rectum. Data were obtained on live weight (gram), eviscerated weight (gram), carcass weight (gram), dressing weight (gram), breast weight (gram), shank weight, thigh weight (gram), drumstick weight (gram) and back weight (gram). The visceral organs observed were liver, lungs, heart,kidney, spleen, gizzard, proventriculus and abdominal fats. At 4th week of age, there were significantly differences in eviscerated weight (Cobb birds; 666,25g and Marshall birds; 578,90g), breast weight (Cobb birds; 176,75g and Marshall birds; 138,40g), gizzard weight (Cobb birds; 32,85g and Marshall birds; 29,25g) and abdominal fats (Cobb birds; 9,45g and Marshall birds; 7,80g) while Cobb birds were favoured. At the 6th week of age; Cobb birds had higher values of live weight, eviscerated weight, carcass weight, dressing weight, breast weight, back weight, lungs, heart, abdominal fats and spleen than its Marshall counterpart. However, at the 8th week of age; live weight for Cobb birds had higher values of 3005,60g, eviscerated weight (2264,00g), carcass weight (2088.80g), dressing weight (2634.55g), breast weight (727.05g), back weight (337.95g), lungs (17.10g) and heart (11.70g) than its counterpart Marshall birds. It can be concluded that the Cobb birds had a better carcass characteristics than the Marshall birds.