Methods to Evaluate the Eggshell Quality of Table Eggs

The objectives of this study were to determine the most suitable probe diameter and egg position to perform the eggshell breaking strength test using a texturometer, as well as the most reliable parameter to estimate eggshell quality when no electronic devices are available. Eggshell quality (eggshell breaking strength, eggshell weight, eggshell percentage, eggshell thickness, shell weight per unit surface area) was evaluated as a function of texturometer probe diameter (2, 10, and 75mm), egg type (white and brown) and egg position (horizontal and vertical). In the experiment, 2520 eggs from 60-week-old commercial layers were separated by specific gravity measured by flotation method in saline solution (1.070 to 1.100 g/cm3 with intervals of 0.005 g/cm3).Data were submitted to analysis of variance in a completely randomized design, and means were compared by Tukeys test (p 0.05). Correlations between characteristics were calculated using the Pearsons method. The results showed that the most suitable probe diameter for the analysis of eggshell breaking strength was 75 mm, independently of egg positioning or type egg. White eggs should be positioned vertically in relation to the probe, whereas brown can be placed in any position. When it is not possible to evaluate eggshell quality using electronic devices, the measurement of shell weight per unit surface area is recommended.(AU)

Methods to Evaluate the Eggshell Quality of Table Eggs

The objectives of this study were to determine the most suitable probe diameter and egg position to perform the eggshell breaking strength test using a texturometer, as well as the most reliable parameter to estimate eggshell quality when no electronic devices are available. Eggshell quality (eggshell breaking strength, eggshell weight, eggshell percentage, eggshell thickness, shell weight per unit surface area) was evaluated as a function of texturometer probe diameter (2, 10, and 75mm), egg type (white and brown) and egg position (horizontal and vertical). In the experiment, 2520 eggs from 60-week-old commercial layers were separated by specific gravity measured by flotation method in saline solution (1.070 to 1.100 g/cm3 with intervals of 0.005 g/cm3).Data were submitted to analysis of variance in a completely randomized design, and means were compared by Tukeys test (p 0.05). Correlations between characteristics were calculated using the Pearsons method. The results showed that the most suitable probe diameter for the analysis of eggshell breaking strength was 75 mm, independently of egg positioning or type egg. White eggs should be positioned vertically in relation to the probe, whereas brown can be placed in any position. When it is not possible to evaluate eggshell quality using electronic devices, the measurement of shell weight per unit surface area is recommended.

Beak trimming by infrared radiation of layers

This study aimed at evaluating beak-trimming methods and intensities on the performance, beak length and uniformity, and egg parameters of commercial layers. During the rearing period, birds were distributed in randomized blocks, with a 2x3 factorial design + two treatments, consisting of beak trimming with infrared (IR) radiation (moderate or severe); three IR intensities (low: 42 nm, intermediate: 46 nm, or high: 52 nm); and two control hot blade (HB) beak trimming treatments (moderate or severe) with eight treatments and five replicates of 21 chicks each, totaling 840 birds. During the growing phase (second experiment) the factorial design was modified to 2 x 3 x 2 + 4, comprising two IR beak-trimming intensities (moderate or severe); three IR radiation intensities (low, moderate and high), second beak trimming at 11 weeks of age or not, and four additional HB beak-trimming treatments (moderate or severe) beak-trimming intensities, and second beak trimming at 11 weeks of age or not. There were 16 treatments with six replicates of seven birds each, totaling 672 laying hens, out of which 576 were selected for evaluation during the production period, with the same number of treatments and replicates of the previous phase. Weight gain (g), body weight (g), body weight uniformity (%), beak length (mm) and uniformity (%), absence of cannibalism (%), livability (%), egg production (%), feed intake (g), feed conversion per eggmass, eggmass, specific gravity, eggshell strength, Haugh unit, % yolk were evaluated. Beak trimming by infra-red radiation may be employed in commercial laying hens.(AU)

Beak trimming by infrared radiation of layers

This study aimed at evaluating beak-trimming methods and intensities on the performance, beak length and uniformity, and egg parameters of commercial layers. During the rearing period, birds were distributed in randomized blocks, with a 2x3 factorial design + two treatments, consisting of beak trimming with infrared (IR) radiation (moderate or severe); three IR intensities (low: 42 nm, intermediate: 46 nm, or high: 52 nm); and two control hot blade (HB) beak trimming treatments (moderate or severe) with eight treatments and five replicates of 21 chicks each, totaling 840 birds. During the growing phase (second experiment) the factorial design was modified to 2 x 3 x 2 + 4, comprising two IR beak-trimming intensities (moderate or severe); three IR radiation intensities (low, moderate and high), second beak trimming at 11 weeks of age or not, and four additional HB beak-trimming treatments (moderate or severe) beak-trimming intensities, and second beak trimming at 11 weeks of age or not. There were 16 treatments with six replicates of seven birds each, totaling 672 laying hens, out of which 576 were selected for evaluation during the production period, with the same number of treatments and replicates of the previous phase. Weight gain (g), body weight (g), body weight uniformity (%), beak length (mm) and uniformity (%), absence of cannibalism (%), livability (%), egg production (%), feed intake (g), feed conversion per eggmass, eggmass, specific gravity, eggshell strength, Haugh unit, % yolk were evaluated. Beak trimming by infra-red radiation may be employed in commercial laying hens.

Production indicators and levels of corticosterone in pullets treated with beak-trimming protocols

The aim of this study was to compare the effects of beak trimming by hot blade or infrared radiation on production indicators and plasma levels of corticosterone in pullets. During the rearing phase, an entirely random delineation was used a 2 x 3 factorial design (two different techniques for beak trimming x 3 strains), a total of six treatments with six repetitions of 20 hens. In the growing phase, the previous treatments were divided into 12, with eight repetitions with seven hens. These treatments were then distributed in a factorial design of 2 x 3 x 2 (two methodologies for beak trimming during rearing phase x three strains x with or without beak trimming at ten weeks of age). In the rearing phase the birds treated by infrared radiation had a lower total consumption and a longer beak length. In the growing phase, the execution of beak trimming at ten weeks of age, led to a lower total consumption and a lower body weight, but a better food conversion, when compared to those hens that did not have beak treatment. Beak trimming at ten weeks did not change the plasmatic levels of corticosterone.(AU)

Production indicators and levels of corticosterone in pullets treated with beak-trimming protocols

The aim of this study was to compare the effects of beak trimming by hot blade or infrared radiation on production indicators and plasma levels of corticosterone in pullets. During the rearing phase, an entirely random delineation was used a 2 x 3 factorial design (two different techniques for beak trimming x 3 strains), a total of six treatments with six repetitions of 20 hens. In the growing phase, the previous treatments were divided into 12, with eight repetitions with seven hens. These treatments were then distributed in a factorial design of 2 x 3 x 2 (two methodologies for beak trimming during rearing phase x three strains x with or without beak trimming at ten weeks of age). In the rearing phase the birds treated by infrared radiation had a lower total consumption and a longer beak length. In the growing phase, the execution of beak trimming at ten weeks of age, led to a lower total consumption and a lower body weight, but a better food conversion, when compared to those hens that did not have beak treatment. Beak trimming at ten weeks did not change the plasmatic levels of corticosterone.

Yolk Color and Lipid Oxidation of the Eggs of Commercial White Layers Fed Diets Supplemented with Vegetable Oils

The objective of this study was to evaluate the influence of the supplementation of vegetable oils rich in polyunsaturated fatty acids to the diet of Leghorn layers on yolk color and on yolk lipid oxidation of eggs stored at room temperature for 10 days. Sixty eggs laid by commercial white layers (Lohmann LSL) fed diets supplemented with different vegetable oils were used. Hens were fed one of the following treatment diets: conventional diet with no oil inclusion (T1); T1 diet with 2.5% linseed oil inclusion (T2); T1 diet with 2.5% canola oil (T3); T1 diet with 2.5% soybean oil (T4); T1 with 5.0% linseed oil (T5); T1 diet with 5.0% canola oil (T6); T1 diet with 5.0% soybean oil (T7); T1 diet with 2.5% linseed oil + 2.5% soybean oil (T8); T1 diet with 2.5% canola oil + 2.5% soybean oil (T9); and T1 diet with 2.5% linseed oil + 2.5% canola oil (T10). Eggs were evaluated as to yolk lipid peroxidation (TBARS values) and yolk color, as determined by colorimetry and subjective sensorial analysis. Data were submitted to analysis of variance and means were compared by the test of Tukey at 5% significance level. It was concluded that the inclusion of vegetable oils in commercial white layer diets does not significantly change egg yolk pigmentation, as colorimetrically evaluated. However, when subjectively assessed, the yolks of the eggs laid by hens fed diets supplemented with vegetable oils tend to be paler. The yolks of the eggs laid by layers fed diets containing sources of polyunsaturated fatty acids presented high lipid oxidation, particularly when compared with those derived from layers fed the diet with no oil supplementation.

Yolk Color and Lipid Oxidation of the Eggs of Commercial White Layers Fed Diets Supplemented with Vegetable Oils

The objective of this study was to evaluate the influence of the supplementation of vegetable oils rich in polyunsaturated fatty acids to the diet of Leghorn layers on yolk color and on yolk lipid oxidation of eggs stored at room temperature for 10 days. Sixty eggs laid by commercial white layers (Lohmann LSL) fed diets supplemented with different vegetable oils were used. Hens were fed one of the following treatment diets: conventional diet with no oil inclusion (T1); T1 diet with 2.5% linseed oil inclusion (T2); T1 diet with 2.5% canola oil (T3); T1 diet with 2.5% soybean oil (T4); T1 with 5.0% linseed oil (T5); T1 diet with 5.0% canola oil (T6); T1 diet with 5.0% soybean oil (T7); T1 diet with 2.5% linseed oil + 2.5% soybean oil (T8); T1 diet with 2.5% canola oil + 2.5% soybean oil (T9); and T1 diet with 2.5% linseed oil + 2.5% canola oil (T10). Eggs were evaluated as to yolk lipid peroxidation (TBARS values) and yolk color, as determined by colorimetry and subjective sensorial analysis. Data were submitted to analysis of variance and means were compared by the test of Tukey at 5% significance level. It was concluded that the inclusion of vegetable oils in commercial white layer diets does not significantly change egg yolk pigmentation, as colorimetrically evaluated. However, when subjectively assessed, the yolks of the eggs laid by hens fed diets supplemented with vegetable oils tend to be paler. The yolks of the eggs laid by layers fed diets containing sources of polyunsaturated fatty acids presented high lipid oxidation, particularly when compared with those derived from layers fed the diet with no oil supplementation.(AU)

Equilibrium condition during locomotion and gait in broiler chickens

The experiment was carried out with the objective of evaluating a methodology to estimate the angulation and equilibrium condition, relating them to gait score and the main diseases of the locomotion system in males and females of commercial broiler strains. A completely randomized experimental design in a factorial arrangement (2x2) was applied, consisting of two sexes and two genetic strains, with five replicates of 53 chickens each. The following characteristics related to broiler locomotion were studied: gait score (GS); incidence of Valgus (VAL) and Varus (VAR) deformities and of pododermatitis (POD); body angle relative the ground (ANG); equilibrium condition (EC); body weight (BW) and breast weight (BrW); and incidence of femoral degeneration (FD), tibial dyschondroplasia (TD) and spondylolisthesis (SPO). GS, and VAL and VAR were assessed inside a broiler house. Birds were then photographed to estimate ANG and EC. Birds were sacrificed at 42 days of age and analyzed for FD, TD, and SPO. Breast percentage was not influenced by sex or strain. Males showed better ANG than females, regardless of strain. Overall, the strains studied showed prostrated EC. The correlation between GS and the evaluated traits was low. There was a moderate to high association between EC and ANG both in males and females. GS showed low correlation with locomotion problems, and therefore, it is a poor indicator of skeletal diseases. On the other hand, the moderate to high correlations of ANG and EC with locomotion problems make them better indicators of bone diseases than gait score, which is possibly more related to EC and body posture than to bone pathologies.

Equilibrium condition during locomotion and gait in broiler chickens

The experiment was carried out with the objective of evaluating a methodology to estimate the angulation and equilibrium condition, relating them to gait score and the main diseases of the locomotion system in males and females of commercial broiler strains. A completely randomized experimental design in a factorial arrangement (2x2) was applied, consisting of two sexes and two genetic strains, with five replicates of 53 chickens each. The following characteristics related to broiler locomotion were studied: gait score (GS); incidence of Valgus (VAL) and Varus (VAR) deformities and of pododermatitis (POD); body angle relative the ground (ANG); equilibrium condition (EC); body weight (BW) and breast weight (BrW); and incidence of femoral degeneration (FD), tibial dyschondroplasia (TD) and spondylolisthesis (SPO). GS, and VAL and VAR were assessed inside a broiler house. Birds were then photographed to estimate ANG and EC. Birds were sacrificed at 42 days of age and analyzed for FD, TD, and SPO. Breast percentage was not influenced by sex or strain. Males showed better ANG than females, regardless of strain. Overall, the strains studied showed prostrated EC. The correlation between GS and the evaluated traits was low. There was a moderate to high association between EC and ANG both in males and females. GS showed low correlation with locomotion problems, and therefore, it is a poor indicator of skeletal diseases. On the other hand, the moderate to high correlations of ANG and EC with locomotion problems make them better indicators of bone diseases than gait score, which is possibly more related to EC and body posture than to bone pathologies.(AU)

Chicken Meat Submitted to Gamma Radiation and Packed with or without Oxygen

The objective of this study was to evaluate the effects on gamma radiation levels on the physical and microbiological characteristics of chicken breast meat. A completely randomized experimental design in a 4x2x3 factorial arrangement was adopted. Treatments consisted of four radiation concentrations (0, 2, 4, or 8kGy), two package sealing methods (with or without vacuum), and three storage times (01, 07, or 14 days), with ten replicates each, totaling 240 chicken breast fillets. Packaging and radiation had no influence (p>0.05) on chicken breast meat pH, water retention capacity, or presence of Salmonella spp. Breast fillets not submitted to radiation and vacuum packed presented higher water retention capacity (p 0.05) than those radiated at 4kGy and vacuum packed. Drip loss in fillets radiated at 8kGy and not vacuum packed was higher (p 0.05) than in non-radiated and non-vacuum packed fillets; however, both were not different from the other treatments. Coliform presence increased with storage time in non-radiated samples; however, when these were vacuum-packed, their development was slower. The results of the present experiment suggest that the use of a low radiation dose (2kGy), combined with vacuum packing, may minimize the harmful effects of storage on chicken breast fillets.(AU)

Chicken Meat Submitted to Gamma Radiation and Packed with or without Oxygen

The objective of this study was to evaluate the effects on gamma radiation levels on the physical and microbiological characteristics of chicken breast meat. A completely randomized experimental design in a 4x2x3 factorial arrangement was adopted. Treatments consisted of four radiation concentrations (0, 2, 4, or 8kGy), two package sealing methods (with or without vacuum), and three storage times (01, 07, or 14 days), with ten replicates each, totaling 240 chicken breast fillets. Packaging and radiation had no influence (p>0.05) on chicken breast meat pH, water retention capacity, or presence of Salmonella spp. Breast fillets not submitted to radiation and vacuum packed presented higher water retention capacity (p 0.05) than those radiated at 4kGy and vacuum packed. Drip loss in fillets radiated at 8kGy and not vacuum packed was higher (p 0.05) than in non-radiated and non-vacuum packed fillets; however, both were not different from the other treatments. Coliform presence increased with storage time in non-radiated samples; however, when these were vacuum-packed, their development was slower. The results of the present experiment suggest that the use of a low radiation dose (2kGy), combined with vacuum packing, may minimize the harmful effects of storage on chicken breast fillets.

Turnover do carbono em sangue e plasma, nas fases crescimento e postura, de codornas japonesas (Coturnix coturnix japonica) / Turnover of carbon in blood and plasma, growth stages and posture, japanese quails (Coturnix coturnix japonica)

O estudo objetivou avaliar o turnover do 13C no sangue e plasma de codornas japonesas utilizando a técnica de isótopos estáveis, para a obtenção do patamar de equilíbrio isotópico que servirá de fundamento para estudos de rastreabilidade. Foram utilizadas 300 aves durante o período experimental de 1-42 e 49-97 dias de idade. Os tratamentos da primeira fase foram constituídos de dietas à base de arroz (C3), contendo ou não farinha de carne e ossos bovinos e um com dieta à base de milho (C4). Nessa primeira fase foi analisado o turnover do sinal isotópico do matrizeiro à base de dietas C4 para dietas à base de C3, como também as diferenças isotópicas das dietas contendo ou não farinha de origem animal. Na segunda fase houve uma substituição de dietas, ou seja, as aves no tratamento C4 da primeira fase passaram a consumir dieta C3, e o tratamento que antes consumia dieta C3 passou para dieta C4. Para determinar a taxa de turnover e o percentual estimado de participação da farinha na composição do material coletado, foi empregado o modelo de diluição isotópica utilizando valores do δ13C. A comparação entre as meias-vidas do sangue e plasma da primeira fase revelou o enriquecimento do δ13C na dieta; já na segunda fase foi possível observar as velocidades de incorporação após a troca das dietas.(AU)

The study aimed to evaluate the turnover of 13C in the blood and plasma of Japanese quail using the technique of stable isotopes to obtain the level of isotopic equilibrium that will be the foundation for studies of traceability. A total of 300 birds during the experimental period of 1-42 and 49-97 days of age. The first phase of the treatments consisted of diets based on rice (C3), with or without meat and beef bones and a diet based on corn (C4). This was first examined the turnover signal farm matrix isotope-based diets based diets C4 to C3, as well as isotopic differences of diets with or without animal meal In the second stage there was a substitution of diets, or C4 treatment of the first stage passes to consume C3-based diet than before treatment and diet consumed C3 to C4 diet. To determine the turnover rate and the estimated percentage of participation of flour in the composition of the collected material was used isotope dilution model using δ13C values. A comparison of the half-lives of blood and plasma from the first phase discloses the enrichment of dietary δ 13C, in the second phase was observed after incorporation speeds exchange diets.(AU)

Effects of dietary clinoptilolite and calcium levels on uric acid and calcium blood concentrations and bone quality of commercial layers

The objective of the present study was to evaluate the effect of clinoptilolite and calcium levels on uric acid and calcium blood profile and bone quality of commercial layers. A total of 576 birds were distributed according to a completely randomized experimental design in a 3x4 factorial arrangement (calcium levels of 2.5, 3.1, or 3.7% and clinoptilolite levels of 0.0, 0.15, 0.25, or 0.50%), into 12 treatments with six replicates of eight birds per cage (experimental unit). The experimental period was 112 days. The experimental diets were based on corn and soybean meal. Results were submitted to analysis of variance and means were compared by the test of Tukey at 5% significance level using SISVAR statistical package. Blood uric acid was significantly influenced by the interaction of the evaluated factors. Clinoptilolite levels significantly increased blood calcium levels. There was no effect of dietary calcium levels on any of the evaluated characteristics. It was concluded that feeding layers with up to 0.50% clinoptilolite does not benefit blood uric acid and calcium concentrations and does not affect their bone quality. When layers at the end of the first laying cycle are fed ad libitum and present 119.50g/hen/day average feed intake, 3.1% dietary calcium promotes 3.7g/hen/day calcium intake, which is sufficient to maintain adequate calcium blood levels and bone quality.(AU)

Effects of dietary clinoptilolite and calcium levels on the performance and egg quality of commercial layers

Among the different feed additives studied in poultry production, clinoptilolite, an aluminosilicate capable of adsorbing harmful substances and of improving live performance and egg and meat quality, was evaluated. The objective of the present study was to evaluate the influence of dietary clinoptilolite and calcium levels on the performance and egg quality of layers. In total, 576 layers were distributed according to a completely randomized experimental design in a 3 x 4 factorial arrangement (three calcium levels - 2.5, 3.1, or 3.7% and four clinoptilolite levels - 0.0, 0.15, 0.25, or 0.50%), with 12 treatments of six replicates of eight birds each. The experiment included four 28-d cycles. The experimental diets were based on corn and soybean meal. Results were submitted to analysis of variance and means were compared by the test of Tukey at 5% significance level using SISVAR statistical package. There was a significant interaction between the evaluated factors for egg production and feed conversion ratio per dozen eggs and egg mass. The lowest calcium level resulted in worse performance and eggshell quality. Clinoptilolite levels affected albumen and yolk content. It was concluded that up to 0.50% inclusion of clinoptilolite in layer diets does not benefit layer performance or eggshell quality. Although the inclusion of only 2.5% calcium in layer diets is not recommended, it is possible to add 3.1% because it promoted similar results as the recommended level of 3.7%.

Effects of dietary clinoptilolite and calcium levels on the performance and egg quality of commercial layers

Among the different feed additives studied in poultry production, clinoptilolite, an aluminosilicate capable of adsorbing harmful substances and of improving live performance and egg and meat quality, was evaluated. The objective of the present study was to evaluate the influence of dietary clinoptilolite and calcium levels on the performance and egg quality of layers. In total, 576 layers were distributed according to a completely randomized experimental design in a 3 x 4 factorial arrangement (three calcium levels - 2.5, 3.1, or 3.7% and four clinoptilolite levels - 0.0, 0.15, 0.25, or 0.50%), with 12 treatments of six replicates of eight birds each. The experiment included four 28-d cycles. The experimental diets were based on corn and soybean meal. Results were submitted to analysis of variance and means were compared by the test of Tukey at 5% significance level using SISVAR statistical package. There was a significant interaction between the evaluated factors for egg production and feed conversion ratio per dozen eggs and egg mass. The lowest calcium level resulted in worse performance and eggshell quality. Clinoptilolite levels affected albumen and yolk content. It was concluded that up to 0.50% inclusion of clinoptilolite in layer diets does not benefit layer performance or eggshell quality. Although the inclusion of only 2.5% calcium in layer diets is not recommended, it is possible to add 3.1% because it promoted similar results as the recommended level of 3.7%.(AU)

Performance and egg quality of Japanese quails submitted to cyclic heat stress

Aiming at evaluating the influence of cyclic temperatures on the performance and egg quality of Japanese quails an experiment was carried out with 480 birds after egg production peak. Birds were housed in a bioclimatic chamber with automatic temperature control that contained two rooms, one maintained at thermoneutral temperature (21 ºC) and the other adjusted for the tested cyclic temperatures (24, 27, 30, 33 and 36 ºC at a time). Each room had a battery of five floors and ten cages, with a capacity of 24 birds per cage, totaling 240 birds per battery. Birds were fed iso-nutritious and iso-caloric diets. Data obtained under the tested cyclic temperatures were compared with those obtained under thermoneutral temperature. At the end of each experimental period (14 days) performance and egg quality parameters were evaluated. A completely randomized experimental design with two treatments (thermoneutral temperature and tested temperature) and ten replicates of 24 birds each. Cyclic increases of 27 ºC and higher in environmental temperature negatively affected bird performance, with reduced feed intake and consequent reductions in egg weight and mass. A cyclic increase of the environmental temperature to 36 ºC reduced the percentage of saleable eggs and egg production.(AU)

Evaluation of a radiographic method to detect tibial dyschondroplasia lesions in broilers

This study aimed at developing radiographic techniques for the early detection of dyschondroplastic lesions in the tibia of broilers. The experiment was carried out at the facilities of UNIFOR/MG and Formiga and UNIFENAS/ Alfenas with 420 one-day-old male Cobb broilers. At 20 days of age, all birds were radiographed and identified with an alpha-numeric metal ring in the right leg. At 40 days of age, 42 broilers previously selected as a function of bone mineral density and lesion thickness scores were again radiographed and scored, and then sacrificed. Their right tibia was removed for gross and histological examination of the growth plate. The results showed that radiographic techniques are correlated with gross and histological examination and that there was no significant differences among techniques (P>0.05). it was concluded that the use of radiographic examination to identify tibial dyschondroplasia in broilers precludes the use of bone mineral density to diagnose this condition. The non-parametric statistical Chi-square test at 5% significance level was used to analyze the results.(AU)

Efeito da idade da matriz sobre o desempenho e rendimento de carcaça de frangos de corte / Effect of broiler breeder age on performance and carcass yield of broiler chickens

Avaliou-se efeito da idade da matriz sobre as características de desempenho, rendimento de carcaça e partes de frangos de corte, criados até 49 dias de idade. Foram utilizados 3600 pintos de um dia, oriundos de ovos de matrizes da linhagem Ross 308, distribuídos segundo um delineamento experimental inteiramente ao acaso, em esquema fatorial 5I2, com cinco idades de matrizes (29, 41, 58, 68 e 98 semanas) e dois sexos, com quatro repetições de 90 aves cada. Aos 21, 28, 35, 42 e 49 dias de idade, cinco frangos por parcela foram amostrados e abatidos após jejum alimentar de oito horas, para avaliação do rendimento de carcaça e partes. A idade da matriz influenciou (P<0,05) o desempenho das aves na fase inicial de criação (1 a 21 dias); os frangos oriundos de matrizes com 29 semanas de idade apresentaram menor rendimento. A idade da matriz não afetou (P>0,05) o rendimento de carcaça nas idades avaliadas. Os frangos oriundos de matrizes com 29 semanas apresentaram melhor rendimento de peito que aqueles de matrizes com 58 semanas. O sexo influenciou (P<0,05) tanto o desempenho quanto o rendimento de carcaça e partes dos frangos de corte. (AU)

The effect of broiler breeder age on performance and carcass yield of chickens reared until 49 days of age was evaluated. Three thousand and six hundred day-old chicks, from Ross x Ross breeder flocks, were assigned to a completely randomized design, in a 5×2 factorial (five broiler breeder ages - 29, 41, 58, 68 and 98 weeks and two sexes) with four replicates of 90 birds each. At 21, 28, 35, 42 and 49 days of age, 5 birds per pen were randomly sampled and processed after a period of 8 hours of feed withdrawal to evaluate carcass and parts yield. Breeder age affected (P<.05) broiler performance during the starter period (1 to 21 days), with birds from breeders with 29 weeks of age showing smaller performance. Carcass and part yields were not affected (P>.05) by breeder age, but broilers from breeders aging 29 weeks showed larger breast yield than broilers originated from breeders with 58 weeks. No differences (P>.05) were observed for other breeder ages. Sex of the broiler chicken affected (P<.05) the performance and carcass yield and parts.(AU)