This experiment aimed at evaluating the influence of different heating times of settable eggs of Cobb 500® broiler breeders before submitting them to different storage periods on egg weight loss, embryo mortality, and hatchability. A total number of 1,980 eggs were distributed in a completely randomized experimental design with a 3 x 3 factorial arrangement, comprising nine treatments with 22 replicates of 10 eggs each. The following factors were analyzed: pre-storage heating periods (0, 6, 12 hours at 36.92°C) and storage periods (4, 9, 14 days at 12.06°C). After storage, eggs were incubated under usual conditions, and were transferred to the hatcher at 442 hours of incubation. Eggs were weighed before heating, incubation, and transference to determine weight loss. Partial hatchability was determined at 480 hours, and total hatchability at 498 hours of incubation. Embryo mortality was determined in non-hatched eggs. It was concluded that heating eggs for six hour before storage improves incubation results as it decreases incubation length and late embryo mortality, therefore its use can be indicated in commercial operations. Storing eggs for 14 days and pre-heating for 14 days and pre-heating for 12 hours severely impair incubation results, and therefore are not recommended.

An experiment was carried out to evaluate the effect of different heating times of settable eggs of Cobb 500® broiler breeders before submitting them to different storage periods on body weight, digestive tract organ weights, and intestinal mucosa morphology of newly-hatched chicks. Settable eggs were distributed in a completely randomized experimental design with a 3 x 3 factorial arrangement: pre-storage heating periods (0, 6, 12 hours at 36.92°C) and storage periods (4, 9, 14 days at 12.06°C). Body weight and relative weights of the yolk sac, heart, liver, proventriculus+gizzard, and intestinal segments were measured in chicks hatching at 480 and 498 hours of incubation. Villi height, width and perimeter, and crypt depth (ìm) were measured in duodenal histological sections. It was concluded that pre-storage heating for six hours of eggs stored for four or nine days increases small intestine weight of newly-hatched chicks, but does not influence the morphology of the duodenal mucosa. Pre-storage heating for 12 hours negatively influences body weight and duodenal mucosa development, and therefore this practice is not recommended. Storage length does not have consistent effect on body weight and development of the gastrointestinal tract.

The matter of animal welfare has led to studies in order to evaluate alternative rearing systems for livestock in order to improve well-being. The semi-intensive system is an alternative method of rearing broilers in which the birds are kept in a poultry house and have free access to a pasture area during the day. It is known that ambient conditions may directly affect the behavior of birds reared in the semi-intensive system. Therefore, this research evaluated the behavior of four broiler strains reared under a semi-intensive system with a shaded area (provided by a black plastic screen - 50%) and the bioclimatic characteristics of this environment when compared with the non-shaded pasture. Thirty-five birds were reared in pens with 4.5 m² and 35 m² of pasture. Ambient variables were measured throughout the day to calculate the indexes of thermal comfort (BGHI and enthalpy). Data was analyzed in a 4 x 2 factorial (4 strains and 2 rearing environments) with 2 repetitions, in order to establish the rate of bird permanence in the pasture. There was an improvement in the ambient conditions of the shaded pasture in the hottest hours of the day (from 10:00 to 14:00 h), i.e., there was a reduction in the mean values of BGHI (approximately 26%) and enthalpy (36%). As a consequence, there was an increase in the rate of permanence in this environment if compared with the non-shaded pasture. Three out of four evaluated strains showed better adaptability to the semi-intensive rearing system.

Aves de quatro linhagens de galinhas para corte foram criadas no sistema semi-intensivo, em 16 boxes, sendo 4 boxes por linhagens, com 4,5 m² de área interna (abrigo) e 35 m² de área de pastejo, com o objetivo de analisar a adaptação dessas linhagens a esse sistema de criação, através de parâmetros ambientais e comportamentais. O período experimental desenvolveu-se entre 35 e 75 dias de idade, durante o qual foram coletados dados relativos à quantidade de aves presentes no pasto, temperatura e umidade relativa nos boxes e no pasto e porcentagem de sombra no pasto. Os parâmetros ambientais monitorados influenciaram o comportamento das aves. A análise bioclimática e a observação do comportamento permitiram diferenciar as linhagens estudadas no que diz respeito à adaptação das linhagens ao sistema semi-intensivo de criação. As aves das linhagens avaliadas mostraram-se adaptadas ao sistema semi-intensivo por demonstrar o comportamento esperado para esse sistema de criação.

Birds of four meat-type chicken lines were reared at the semi-intensive system with the objective of evaluate the adaptation to these breeding systems through environmental and behavioural parameters. The experimental period took place between 35 and 75 days of age during which it was collected data of number of broilers in the pasture, air temperature and relative humidity inside the boxes and in the pasture areas, and percentage of shadow in the pasture areas. Environmental factors influenced the behaviour of the evaluated lines. The bioclimatic analysis and the observation of the chicken behaviour allowed to discriminate the studied lines regarding to the adaptation to the semi-intensive breeding system. The broilers of the evaluated lines showed adaptation to the semi-intensive system, presenting the expected behaviour for this breeding system.

Aves de duas linhagens, sendo uma portadora do gene pescoço pelado (Na_) que determina redução no empenamento, e outra não portadora, com empenamento normal (nana), foram submetidas a estresse térmico gradativo (38, 40 e 42ºC), em câmara climática, nas idades de 28, 35 e 42 dias, com o intuito de se verificar a resistência ao estresse térmico. Foram verificadas diferenças significativas entre a temperatura retal média e a taxa respiratória média da linhagem de empenamento normal quando comparada com a linhagem de pescoço pelado, em todas as idades e períodos de estresse. Foram verificados valores mais altos das aves de empenamento normal, demonstrando a influência do conjunto temperatura de estresse térmico e idade. Pôde-se constatar que houve diferença significativa entre as linhagens para as médias de perda de peso apenas aos 35 dias de idade. Os resultados obtidos sugerem que a linhagem de pescoço pelado (Na_) possui maior resistência ao estresse térmico em relação à linhagem de empenamento normal (nana).

Birds of two lineages, a carrier of the Naked Neck gene (Na_) that determines reduction in the feathering and other non-carrier (normal feathering, nana), were submitted to thermal stress (38, 40 and 42ºC) in climatic chambers at 28, 35 and 42 days of age to verify the resistance to the thermal stress. Significant differences were verified among the mean rectal temperature of the normal feathered lineage when compared with the naked neck lineage, in all the ages and stress periods, with higher values in the normal feathered birds. The same result was found for mean respiratory rate. Significant difference was found for weight loss between the two lineages only at the age of 35 days. The results obtained suggest that the Naked Neck lineage possesses higher resistance to the thermal stress in relation to the normal feathered lineage.

Este trabalho avaliou o efeito do genótipo e do sexo sobre os valores de hematócrito em galinhas para corte. Foram utilizados 180 reprodutores, provenientes de 18 genótipos experimentais, dos quais amostras de sangue foram coletadas para determinação da porcentagem de células sanguíneas. Para o fator genótipo foi possível distinguir dois grupos, com médias variando de 45,83 a 41,69% e 41,24 a 37,21%. Já para o fator sexo, os valores apresentaram diferença significativa, com valores de 46,20 ± 4,14% para machos e 35,74% ± 3,16% para fêmeas. Concluiu-se que o genótipo e o sexo influenciaram o valor hematócrito em galinhas reprodutoras pesadas, além de agrupar todos os genótipos em dois grupos.

The objective of this research was to evaluate the effect of the genotype and sex on the value of meat-type chicken hematocrit (percentage packed cells volume). One hundred and eighty breeders of 18 experimental genotypes were used. Individual samples of blood were collected and the percentage packed cells volume was determined. For the factor genotype, it was possible to distinguish two different groups with averages changing from 45,83 to 41,69% and 41,24 to 37,21%. For sex, the values showed significant difference with values of 46,20 ± 4,14% for males and 35,74 ± 3,16% for females. In conclusion the genotype and sex influenced the hematocrit value in meat-type chickens, above to cluster every genotypes in two groups.