Two early feathering sire lines (B1 and B2), two late feathering dam lines (A1 and A3), and an early feathering dam line were evaluated to determine differences in growth, in lengths of primary feathers, in under-wing and rectal temperatures, and in feed intake until the birds were 20 weeks old. The chicks were hatched from eggs collected from 35-week-old hens of pure line broiler flocks. Data were collected at hatch, and at 1, 2, 4, 6, 8, 12, and 20 weeks old Thirty males and 30 females were evaluated for each line. The early feathering genotypes (A2, B1 and B2) had longer primary feathers until they were six weeks old. They also had higher under-wing and rectal temperatures and higher live weight compared with the late-feathering lines (A1 and A3) at one and two weeks old. The males were heavier than females at all ages. However, under-wing and rectal temperatures were similar in males and females at all ages. A positive correlation was observed between the length of primary feathers and live weight in A2, B1, and B2 at six weeks, whereas a negative correlation was observed between the rectal temperature and the length of primary feathers in A1 and A3 at 4 and 20 weeks old.

ABSTRACT This study aimed to determine the effects of the variation in body weight (BW) in pure lines even after selection on the BW and feed conversion ratio (FCR) of offsprings in broiler pure-lines. The males of the dam (A1) and sire (B1) line were grouped according to their BW after selection at the 6th and 12 th weeks of age. In the sire lines, the heaviest males at six weeks of age were selected (300), and the selected males were divided into three groups in terms of BW as average (B11: 100 males), high (B12: 100 males), and the highest (B13: 100 males). In the dam lines, the selected males were divided into three groups as an average (A11: 100 males), low (A12: 100 males), and high BW (A13: 100 males). In the dam line, offsprings of males with average and high BW had the highest BW at 42 days of age compared to the low BW group (p<0.05). However, there was no statistically significant difference in BW between the BW groups in the offsprings of the sire line. Offsprings of dam line males with average and higher than average BW had better FCR values. However, there was no significant change in FCR between the offsprings of the sire line BW groups. As a result, it is thought that by preserving the variation at a certain level in future generations, a significant improvement can be achieved in the BW and FCR by selecting heavier males.

ABSTRACT Broiler pure lines are valuable breeding species and morphometric traits are advantageous for the selection of breast yield since they could be applied practically and without any negative impact on welfare. In this study, live weight (LW), carcass weight and ratio (CW and CR), breast weight and ratio (BW and BR), abdominal fat weight and ratio (AFW and AFR), morphometric traits such as breast width, length and index (BWD, BL and BI) were investigated in broiler pure lines. The research material consisted of 3 dam (A1, A2 and A3) and 2 sire (B1, B2) pure lines of 42 days of age. LW, CW, BW, AFW, AFR, BR, BL, BWD and BI values were different between the two lines (p<0.05). LW, CW, BW and BI were higher in sire lines. The relationship between breast weight and index were also higher in sire and dam lines than the relationships between breast width and length separately (in sire lines: BWD: 0.73; BL: 0.79; BI: 0.79, in dam lines: BWD: 0.79; BL: 0.74; BI: 0.84). In addition, high r 2 values were determined in regression equations for BW estimation in dam and sire lines (0.836 and 0.857, respectively). Because of the significant correlations between breast yield and its morphometric traits, it is seen that more feasible, ease of measurement, protection of breeding resources and welfare. It is thought that the use of breast index which shows a higher correlation compared to these traits will increase selection efficiency instead of using breast width and length separately.