Fernando da Costa Baêta

Índice térmico ambiental de produtividade para frangos de corte

In this study, the influence of temperature, relative humidity and air velocity in the development process of Avian Farm male chickens was analyzed in order to develop an environmental thermal index for productivity of broiler chickens - IAPfc. The chickens were first raised from 1 to 21 days of age in a conventional poultry-shed under natural conditions. Between 22nd and 42nd day (slaughter) the chickens were kept in climatic chambers. The treatments consisted of combination of levels of variables: temperature (t) 16, 20, 26, 32 and 36 oC; relative humidity (u) 20, 34, 55, 76 and 90%, and air velocity (v) 0; 0.6; 1.5; 2.4 and 3.0 m s-1, according to the central rotatable composite design of the response surface methodology. The experimental diets attained the suggested requirements of each development phase. The diet composition was the same in all treatments. The analyzed parameters were: daily weight gain, feed intake, rectal temperature and respiratory rate. The statistical model obtained was IAPfc = 45.6026 - 2.31072 t - 0.368331 u + 9.70922 v + 0.0549243 t2 + 0.0012183 u2 + 0.66329 v2 + 0.0128968 tu - 0.300928 tv - 0.0595245 uv, which is based on the animal performance and physiological parameters.

Thermal environment and gas concentrations in poultry houses during heating.

Currently, the national and international markets are stressing actions for environmental preservation, including data collection regarding concentrations or emission of harmful gases generated from animal production. The lack of information regarding this subject is the reason for this study which is to diagnose the concentrations of carbon monoxide and carbon dioxide associated with the thermal comfort of broiler chickens in poultry houses. Two different types of air renovation for heating were studied: ventilation by negative pressure and by positive pressure, during winter in the southern region of Brazil. For evaluation of the thermal environment, randomized blocks were used in split-plot design with two repetitions. The index of the black globes temperature and humidity indicated the best conditions for thermal comfort environment in the first week of the life of the birds for positive pressure of the system. The highest gas concentrations were detected in the morning for both air renovation methods, with concentrations within the acceptable levels for good bird development.

ATUALIZAÇÃO DAS TEMPERATURAS DE CONFORTO TÉRMICO PARA FRANGOS DE CORTE DE ATÉ 21 DIAS DE IDADE

Em decorrencia de alteracoes na genetica e nutricao, bem como na aclimatizacao das aves de corte ao clima do Brasil, as temperaturas atualmente preconizadas como otimas para criacao podem estar defasadas. Objetivou-se com esta pesquisa atualizar os valores de temperatura ambiente que caracterizam o conforto termico para frangos de corte de um a 21 dias de idade, sob condicoes brasileiras de producao. Esta pesquisa foi conduzida com 600 aves da linhagem COBB, que foram distribuidas em cinco câmaras climaticas, mantidas sob diferentes temperaturas, durante as tres primeiras semanas de idade. Durante o periodo experimental, os valores de temperatura media para as semanas de um a tres foram reduzidos progressivamente, constituindo-se de cinco tratamentos: T27/24/21; T30/27/24; T33/30/27; T36/33/30 e T39/36/33. Verificou-se que as aves mantidas sob o tratamento T3027-24 apresentaram melhor desempenho zootecnico quando comparadas as demais condicoes ambientes. Com base nos modelos de regressao obtidos, os valores de temperatura ambiente que proporcionam o maior ganho de peso para o periodo inicial de criacao de frangos de corte foram 31,3; 25,5 e 21,8 oC, respectivamente, na primeira, segunda e terceiras semanas de vida dos animais.

Air quality, thermal environment and performance of swines raised in farrowing with different dimensions

The phase of swine nursery is considered a critical one, in which the animal is exposed to environmental conditions of the premises on which it is located, without the matrix protection and inserted into a social collective and unknown environment. This phase requires a more heated thermal environment and, because of that, on winter time the shelters are kept more closed, which can cause damage in terms of renewing the air. This work has the objective of evaluating two different sizes of farrowing on winter time, considering thermal environment, air quality and performance of animals located in these facilities. We used two different sizes (I and II), both without any kind of heating. Were measured instantaneous concentrations of NH3 (ppm), CO (ppm) and CO2 (ppm). Data relating to thermal comfort environment (temperature and humidity) were collected continuously. It was concluded that the concentration of CO2 and NH3 gases, measured in both farrowing, did not reach levels that could harm the health of animals; with no measurable concentration of carbon monoxide gas in any of these, the thermal environment in the farrowing during the studied time was considered comfortable.

Efeito da temperatura sobre o desempenho da rã-touro (Rana catesbeiana Shaw, 1802)

Este estudo foi realizado para avaliar os efeitos do ambiente sobre a performance de ra-touro (Rana catesbeiana Shaw, 1802), criada em gaiolas de fibra de vidro instaladas no interior de estufas climatizadas. Apos um periodo inicial de 15 dias de adaptacao as instalacoes, a temperatura constante de 25,0oC, os seguintes tratamentos foram aplicados: temperaturas de 23,0; 26,0; 29,0; 32,0; e 35,0oC, por 30 dias, para ras com 100 g PV inicial; 24,5; 26,0; 27,5; 29,0; 30,5; e 32,0oC, tambem por 30 dias, para ras com 20 g PV inicial; e a combinacao das temperaturas de 26,0 e 29,0oC com os fotoperiodos de 8, 12 e 16 h de luz a cada 24 horas, para ras com 100 g PV inicial. Derivando-se as equacoes de regressao que explicam os efeitos de temperatura sobre o desempenho das ras, estimaram-se melhores ganhos de peso a temperatura de 27,6 e 30,1oC, para ras com 100 e 20 g PV inicial, respectivamente, com melhor crescimento a 28,2oC, para as ras de 100 g PV inicial, e a 29,7oC, para as ras de 20 g PV inicial. A temperatura interagiu com fotoperiodo nos seus efeitos sobre ganho de peso e crescimento corporal, peso e rendimento de carcaca, consumo de alimentos e conversao alimentar.

SISTEMAS DE RESFRIAMENTO EVAPORATIVO E O DESEMPENHO DE FRANGOS DE CORTE

The thermal conditions inside poultry houses are very important for the success of this business. It is however necessary to have an adequate animal thermal confort and a minimum cost of material, equipment and energy. This experiment was carried to verify the effect of evaporative cooling systems on the performance of poultry. The building was divided in four equal sectors. The treatments consisted of ventilator and spraying system (VNB), high rotation ventilator and spraying system (VNA), spraying system (NEB), and spraying system connected to the ventilator (NEV). Feed intake, weight gain, mortality of poultry were recorded and the food conversion calculated. It is shown the evaporative cooling systems (VNA e VNB) presented the best results, increasing weight gain with lower values of food conversion and mortalily. The worst results were found for the spraying system connected to the ventilator (NEV).

Productive and bioeconomical performance of broiler chicks grown under different heating systems

ABSTRACT - This experiment was carried out in two phases to study the effect of different heating systems on the productive and bioeconomical performances in broilers. Five hundred one-day broiler chicks, 50% male and 50% female, in each protected circle, were allotted to a randomized block design with seven treatments and four blocks. The heating systems were: fiber glass plate without plastic sheet cover, fiber glass plate with plastic sheet cover; built-in floor resistance without plastic sheet cover, built-in floor resistance with plastic sheet cover; mortar plate without plastic sheet cover, mortar plate with plastic sheet cover, and brooder heating gas. Heating was maintained up to the 21st days of age, beginning with the temperature of 35oC in the first week with a reducing of 3oC by each week. Live weight, weight gain, feed intake, feed:gain ratio and mortality were evaluated. The electric energy and gas expenditures were recorded during all bird heating period in order to compare the different heating systems cost. The heat electric system with mortar structure plate and plastic sheet cover was the most indicated, by promoting good thermal conditions and higher gross margin at the end of the growing period.

Estufas climatizadas para experimentos ambientais com rãs, em gaiolas

Six acclimatized incubators were initially installed in the Experimental Frog Farm of the Federal University of Vicosa and later in Experimental Frog Farm of the Federal University of Rio Grande, with the objective of accomplishing experiments to evaluate the effects of the environment on frogs performance in cages of fiber glass. Environments with temperatures of 25oC and photoperiod of 12/12 hours of light/hours of darkness (h L/D) were available to frogs adaptation during 15 days before each experiment. The treatments consisted to simulate environments with temperatures varying from 20 to 35oC and photoperiods of 8/16, 12/12 and 16/8 h L/D. They were accomplished experiments with bullfrog (Rana catesbeiana Shaw, 1802) and with butterfrog (Leptodactylus ocellatus Linnaeus, 1758). In these incubators it was possible to estimate that: a) the highest weight gain of bullfrog was obtained between 27.6 and 29.7oC, with better growth between 28.2 and 30.1oC; for butterfrog the best gain and alimentary conversion were verified at 28.6 and 28oC, respectively; b) temperature interact with photoperiod affecting the frogs performance and gonadal development; c) at 27.7oC (temperature of thermal comfort) there will be less frogs inside of water; d) the highest cloacal temperature: 32.1oC, in the dry part, and 33.8oC, inside of water, at 35oC, evidenced the bullfrog thermoregulation; e) the tetraiodotironine (T4) level in the plasm decreases in the temperature of thermal comfort; f) butterfrog was conditioned to the routine handling, coming around feeder at eater time.

Efeito da temperatura e do fotoperíodo sobre o desenvolvimento do aparelho reprodutor de rã-touro (Rana catesbeiana Shaw, 1802)

The effects of the temperature and of the photoperiod on the bull frog sexual maturation of frogs weighing 94.22 g ± 12.03, maintained for thirty days under temperatures of 20, 23, 26, 29, 32 and 35°C, with photoperiod of 12/12 hours of light/hours of darkness (h L/D), were evaluated. Temperature affected the weights of the fat body and liver, that varied according to quadratic models, and higher weights of fat body at 27.27°C and of liver at 26.81°C were considered. The ovaries heavier than 28.36°C and oviducts heavier than 28.77°C were estimated. Temperature affected the sexual maturation of the frogs, evaluated by numeric indexes. In a longer experiment, frogs with initial weight of 95.31 g ± 8.46, were submitted to the combination of the temperatures of 26.0 and 29.0°C with photoperiods of 8/16, 12/12 and 16/8 h L/D, until they reach the gonadal maturity. Temperature interacted with photoperiod in its effects on the development of the reproductive organs of bullfrog. Temperature affected the diameter of the abdomen/distance relation between the eyes, with higher values calculated for 26°C. It was considered that the highest ovocites diameters are obtained under a temperature of 26.0°C, with photoperiod of 12.6/11.4 h L/D.

Evaluation of a simplified model for estimating energy balance in broilers production housing

A simulacao do comportamento termico de galpoes avicolas com e sem Sistemas de Resfriamento Adiabaticos Evaporativos (SRAE) permite aos tomadores de decisao avaliarem a viabilidade economica e os custos da instalacao de um empreendimento na avicultura de corte. Para operacionalizacao desta investigacao, o primeiro passo foi a execucao do teste do modelo de comportamento termico desenvolvido por Gates et al. (1995) para galpoes avicolas nos Estados Unidos, com base na hipotese de que este modelo, utilizando-se galpoes climatizados, como sugerido pelos autores, possa ser usado em condicoes brasileiras. O modelo se mostrou adequado para o objetivo previsto, na forma indicada por Gates et al. (1995) para galpoes com vazao massica do ar elevada, (120,8 kg de ar por segundo ou maior). E necessario um fator de correcao referente a uma serie de fontes de calor desprezada pelo modelo para galpoes sem uma grande vazao massica, ou a inclusao dessas fontes.