Snezana Bogosavljevic-Boskovic

Carcass characteristics of two strains of native broilers (White Naked Neck and Black Svrljig) fattened under a semi-intensive system

This study involves the analysis of two breeds [Naked Neck (NN) and Svrljig chickens (Sv)], that is, strains [White Naked Neck (WNN) and Black Svrljig strain (BSv)] of chickens (birds) of both sexes reared under a semi-intensive system until day 84 of age. At 28 days of age, the test birds were kept in a litter housing system (about 8 birds/m 2 ), following which they were provided a free-range paddock at 4 m 2 /bird. The following parameters were evaluated in the two strains and sexes of broilers (totalling 56 chickens) aged 84 days: body weight at slaughter, carcass weight, yields of breasts, thighs, drumsticks, wings, pelvis, back, head, neck, feet, abdominal fat and giblets. At the end of the fattening period, the test broilers of both sexes of the WNN strain had higher values (P 0.05); however, a similar yield was obtained for ready to grill carcass (61.73 to 61.99%) when compared with the black Svrljig strain. The differences obtained were not statistically significant (P>0.05). In addition to the genotype (breed, strain), broiler sex had a statistically significant effect (P<0.001; P<0.01; P<0.05) on body weight, carcass yield, yields of drumsticks and thighs, wings, head, feet, giblets and abdominal fat. Specifically, male broilers were found to have higher live body weight (1669.29 to 1480.07 g), carcass weight (1342.86 to 1198.28 g), yields of head (5.13 to 4.39%), drumsticks and thighs (34.26 to 33.96%), feet (5.39 to 5.06%) and giblets (6.46 to 6.31%), whereas the relative yields of carcass (conventional processing (CP): 80.96 to 80.44%; ready to roast (RR): 73.02 to 72.19%; ready to grill (RG): 62.30 to 61.45%), wings (14.06 to 13.76%) and abdominal fat (1.13 to 1.07%) were higher in female broilers.

Effects of intensity of light and stocking density on broiler body weight and yield of valuable carcass parts

In order to determine the effect of intensity of light and stocking density, as well as the interaction of light intensity x stocking density on body weight and individual carcass traits, an experiment was performed on 1200 broilers of the Ross 308 genotype. The investigated factors were the intensity of light (LI): 20 lx (K) ; 150 lx (O) and stocking density (SD): 10 broilers/m (A); 13 broilers/m (B); 15 broilers/m (C), in 4 repetitions. The light source was incandescent bulbs of adequate intensity and a light program 16L: 4D: 2L: 2D was applied. Broiler body weight was controlled on 11th, 21st, 35th and 42nd day, by individual measurement of all chickens in the trial. The average sample containing 12 chickens per treatment with equal gender representation (total of 72 broilers) was used to study the slaughter quality of carcasses based on the parameters of absolute and relative yield of more valuable carcass parts (breast, thighs and drumsticks) and meat in the more valuable parts of the carcass. The effect of light with different intensity on the body weight differed depending on the broiler rearing phase. The interaction effect of the intensity of light and stocking density on the body weight of broilers was confirmed in all stages of growing up to the age of 42 days. A higher intensity of light (150 lx) showed the potential to alleviate the negative effects of higher stocking density (15 broilers/m) on the final body weight of the broiler. The carcass traits were not significantly affected by the intensity of the light, while the stocking density, as well as the intensity of the light x stocking density did influence the yield of whole breast and the yield of breast meat.

Meat quality parameters of broilers from different rearing systems

Bearing in mind certain established European Union regulations on non-industrial poultry meat production, experimental investigations were conducted with the aim to examine the effect of two different rearing systems (free-range rearing and extensive rearing in the chicken pen) on some meat quality characteristics. Investigation results on the shares of muscular tissue, bones and skin in major carcass parts (breasts, thighs and drumsticks) were used as poultry meat quality parameters. Based upon the obtained study results, it could be concluded that a somewhat higher meat share in breasts and drumsticks was recorded with the free-range-reared broilers as compared to the extensively reared ones. A somewhat higher meat share in the drumsticks was registered with the hens whereas other differences from the point of view of the sex effect were small.