Bands of respiratory rate and cloacal temperature for different broiler chicken strains

Abstract

-The objective of this investigation was to estimate ideal bands of respiratory rate and cloacal temperature for broiler chicken strains during the rearing period and to evaluate the influence of time of exposure on bird physiological variables under different thermal stress conditions. The research was conducted in a climatic chamber during the six weeks of the rearing period, with Avian and Cobb strains exposed to two climatic conditions (comfort and stress), in three distinct times of exposure, in three conditions (before going to the chamber; at the end of exposure time; 30 minutes after the end of exposure), in four treatments: comfort with 60 minutes of exposure; stress with 30 minutes of exposure; stress with 60 minutes of exposure; stress with 90 minutes of exposure. Bands of respiratory rate and cloacal temperature were elaborated for both strains, for each one of the weeks of the rearing period. Strains differed, regardless of treatments and conditions adopted in the research on the third, fifth and sixth weeks of life in relation to the cloacal temperature. The Cobb strain is more tolerant to thermal stress in comparison with the Avian. There was difference for both variables between comfort and stress, but time of exposure to stress did not influence the physiological response of birds, except for cloacal temperature on the second week of life.

Temperature mapping of trucks transporting fertile eggs and day-old chicks: Efficiency and/or acclimatization?

“…The temperature inside of the chick boxes was found below the ideal ranges (35 -32 °C) as recommended by Lin et al (2005); Mujahid & Furuse (2009);Nascimento et al (2012;. This aspect brings an important clue showing that the chicks suffered cold stress during transportation.…”

“…Also, Damron et al (1994); Gast & Holt (2000); Anderson et al (2008); Nazareno et al (2013) observed that these same critical regions presented the equivalent results in the thermal profile during egg transportation. The best relative humidity regions in the day-old chick transport happened to be found from the back of the truck to a small area in the front of the lorry (50 -60%) as suggested by Lin et al (2005); Mujahid & Furuse (2009) ;Nascimento et al (2012;. However, it was possible to observe some critical regions in the lorry that presented nucleus with relative humidity out of the ideal ranges (20 -50% and 70 -80%).…”

Qualidade de pintos em função do microclima, tempo de espera e idade de matrizes

“…Os menores valores médios foram observados nas idades de 54 e 46 semanas (38,0 e 38,2 °C) no tempo de espera 14 h, respectivamente; ainda foi possível verificar que em todos os tempos de espera estudados, assim como para as diferentes idades de matrizes, os valores de temperatura cloacal encontrados nesta etapa demonstraram que os pintos de um dia sofreram estresse por frio pois os valores de temperatura cloacal estiveram abaixo das faixas ideais (41 -42 °C) (Meltzer, 1987;Marchini et al, 2007;Nascimento et al, 2012).…”

“…Massa dos pintos machos e fêmeas de diferentes idades de matrizes após a espera no incubatório Médias seguidas de mesma letra, maiúsculas nas linhas e minúsculas nas colunas, não diferem entre si pelo teste Tukey (p > 0,05) Tabela 4. Temperatura cloacal (°C) dos pintos de diferentes idades de matrizes após a espera no incubatório De acordo com a literatura a temperatura ambiente recomendada para a termoneutralidade de pintos nos primeiros dias de vida deve estar entre 32 -35 °C (Meltzer, 1987;Marchini et al, 2007;Abreu et al, 2012;Nascimento et al, 2012Nascimento et al, , 2013. No entanto, a temperatura média da sala de pintos no momento da aquisição dos dados estava abaixo dessa faixa.…”

“…A justificativa para este evento foi que no tempo de espera 0 h os pintos de um dia ainda não estavam estressados, porém, com o passar do tempo essas aves ficaram estressadas e depois foram se adaptando com o microclima do ambiente das caixas de transporte. Apesar da oscilação da frequência respiratória notou-se que foram poucos os momentos em que esta variável esteve dentro das faixas ideais (48 -57 mov min -1 para pintos de corte na 1ª semana de criação) conforme Nascimento et al (2012).…”