Roberta Passini

Intervenção ambiental na cobertura e ventilação artificial sobre índices de conforto para aves de corte

Este trabalho objetivou avaliar manejos de cobertura e ventilacao artificial sobre indices de conforto de frangos de corte. Aplicou-se, para avaliacao dos indices termicos, delineamento inteiramente casualizado, em parcela subdividida, com arranjo fatorial de tratamentos 2 x 2, sendo: dois manejos de cobertura (com e sem pintura reflexiva) e dois manejos internos (com e sem ventilacao artificial) totalizando 4 tratamentos, avaliados durante 40 dias, tidos como repeticao. Os estudos foram conduzidos no IFG - Campus Urutai, de dezembro/2009 a janeiro/2010. Como variaveis ambientais foram coletadas as temperaturas de bulbo seco, bulbo umido, globo negro, umidade relativa e velocidade do vento, sendo posteriormente calculados os indices termicos: ITU, ITGU, ITE, TMR e CTR. Os dados foram analisados pelo programa computacional SISVAR por meio da analise de variância e teste de comparacao de medias. Utilizou-se o Teste de Scott Knott considerando-se 5% de significância. A combinacao de pintura branca na cobertura e ventilacao artificial mostrou-se eficiente na melhoria do conforto termico do ambiente estudado. A utilizacao de pintura ou ventilacao artificial de forma isolada nao foi eficiente.

Parâmetros de fermentação ruminal em bovinos alimentados com grãos de milho ou sorgo de alta umidade ensilados

ABSTRACT - Ruminal fermentation parameters of diets containing high moisture sorghum silage in replacement of high moisturecorn silage were studied in 12 dry cows (584 kg of BW). A completely randomized design was used with three treatments: high moisturesorghum silage replacing high moisture corn silage at levels of 0, 50, and 100%. Diets contained high moisture corn or sorghum silages,extruded soybean, urea, oat hay ( Avena sativa sp.), mineral supplement and monensin. The trial extended for 21 days, the last one usedfor ruminal sampling at 0, 2, 4, 6, 8, 10 and 12 hours after meal. Additionally, in situ degradability of oat hay dry matter and neutraldetergent fiber was evaluated. There was not difference in total volatile fatty acids (VFA) production in the rumen, molar percentageof acetate, propionate and butirate, acetate/propionate ratio, ruminal pH, ammoniacal nitrogen (NH 3 -N) concentration, ruminal liquidturnover and ruminal liquid volume. Degradability of hay dry matter and neutral detergent fiber was not different. No improvement onthe ruminal fermentation parameters with the association of grains was observed.Key Words: cows, degradability, high moisture, nutrition, rumen

Thermal comfort in reduced models of broilers' houses, under different types of roofing materials

The research was developed to evaluate the use of different types of roofing materials regularly used in poultry houses. Measurements of thermal comfort were made through the use of techniques such as the Black Globe and Humidity Index (BGHI), the Thermal Heat Load (THL) and Enthalpy (H). Conducted in the State University of Goias, during the months of April and May, 2011, the experiment was composed of five different treatments: AC - Asbestos cement tiles, BA -Bamboo tiles, BAP - Bamboo tiles painted in white, FB -Vegetable fiber tiles and bitumen, FBP -Vegetable fiber tiles and bitumen painted in white. The experiment consisted in 15 repetitions, which were considered the different days of measurements taken. Throughout the studied period, the time of the day considered the least comfortable was the one observed at 2:00pm, and the coverage of vegetable fiber and bitumen showed the highest value of BGHI (84.1) when compared to other types of coverage, characterizing a situation of lower thermal comfort, and no difference was found for THL and H on treatments in the studied region.

Efeitos da enramicina e monensina sódica sobre a digestão de nutrientes em bovinos alimentados com dietas contendo alto nível de concentrados

The objective of this trial was to study the effects of enramycin and sodium monensin administration on total digestibility of diet nutrients and digestible dry matter intake in bovine. Twelve non-pregnant and non-lactating cows (675 kg ± 63 BW) were randomly assigned to three treatments: control group, enramycin-treated group or monensin-treated group. Animals received a diet containing 60% of concentrates (corn, soy bean meal and minerals) and 40% of forage (sugarcane). Treatments were 20 mg/animal/day of enramycin or 300 mg/animal/day of monensin. Trial lasted 21 days, the last 10 used for external marker administration (15 g of chromic oxide/animal/day) and the last 5 for feces collection and feed sampling. None of the antibiotics affected digestible dry matter and TDN intake and the digestibilities of dry matter, crude protein, ether extract, acid detergent fiber, neutral detergent fiber, starch, gross energy or total digestible nutrients.

Efeitos da enramicina e da monensina sódica no consumo de matéria seca, na fermentação ruminal e no comportamento alimentar em bovinos alimentados com dietas com alto nível de concentrado

The objective of this research was to study the effects of enramycin and sodium monensin administration on dry matter intake, ruminal fermentation and alimentary behavior in bovine. Twelve non-pregnant and non-lactating cows (675 kg ± 63 of BW) were randomly assigned to three treatments: control group, enramycin treated group or monensin treated group. Animals received a diet containing 60% of concentrates (corn, soybean meal and minerals) and 40% of forage (sugarcane). Treatments were 20 mg/animal/day of enramycin and 300 mg/animal/day of monensin. Trial lasted 21 days, and at the 21st was used for ruminal fluid sampling at 0, 2, 4, 6, 8, 10 and 12 hours after 1st meal. Monensin increased total VFA concentration 12 h after feeding in relation to others treatments and decreased the acetic:propionic ratio at times 0 and 6 h, in relation to enramycin, but not when compared to control. The two ionophores tested did not influence the molar proportion of acetic, propionic or butyric acids, pH, ammoniacal-N concentration, or DM intake and intake behavior, evaluated during activities of feeding, rumination and idleness.

Assessing different holding pen cooling systems through environmental variables and productivity of lactating cows

This studyaimed to assess different holding pen climatization systems for dairy cattle through environmental variables, milk production and economic indexes. Sixteen lactating cows were used, distributed in a 4 x 4 Latin square design consisting of four groups of four animals, assessed in four periods, seven days each, and in four holding pen environments: SUN– external environment (in the sun), SHA– 80%-protection polypropylenemesh shading, SHA + SPR– 80% polypropylene mesh shading + water sprinkling, SHA + SPR + VEN – 80% polypropylene mesh shading + water sprinkling + ventilation. The animals remained for 30 minutes in their respective environments. In this period, environmental variables were collected using data loggers, and the milk produced, in kg, by each animal was subjected to the treatments. Fixed and variable costs were calculated for economic analysis. The SHA + SPR + VEN treatment presented itself as the best environment (p < 0.05), promoting an increase in the milk produced by the cows and in themonthly income, with 44 days for return on investment.

Heat tolerance test in Girolando cattle for two degrees of consanguinity in midwestern region of Brazil.

The effects of temperature, relative humidity, wind velocity, and solar radiation in predominantly tropical countries, like Brazil, affect dairy production directly, as the heat tolerance is a serious obstacle to the productive process. The present study objective was to apply the Heat Tolerance Test (HTT) for Girolando cows into two genetic groups and check its use for dairy cattle. The experimental design was randomized assigned that used twenty Girolando cows; ten were ½-blood animals and ten were 5/8-consanguinities animals. The HTT was applied over three nonconsecutive days. The test consisted of the evaluation of rectal temperature before and after direct solar radiation exposure for one hour. There was significant statistical difference for HTT (P<0.05) by “t” test for the two genetic groups. The mean values observed for HTT were 9.51 and 9.72, respectively, for the ½-blood and 5/8-Girolando cows, indicating the major heat tolerance to the 5/8-Girolando group. By the obtained results, it was concluded that it’s possible to the use the HTT as a tool for selection of dairy cattle pedigree or groups that are more tolerant to heat stress.

Efeitos da substituição do milho pelo resíduo de panificação sobre as características de carcaça de novilhos da raça Holandesa

The effects of the addition of bakery waste (BW) replacing corn in the diet of Holstein steers was studied on carcass dressing and meat quality. Four treatments were applied, respectively, 0%, 10%, 20% and 30% of bakery waste replacing corn in the concentrated mixture. The animals were fed with complete pelleted mixtures, with 30% of Coast-cross hay (Cynodon dactylon L.) as roughage. A randomized block design with four treatments and five repetitions, total of 20 animals, was used. The experiment began when the calves reached 90 kg of live weight and lasted for 120 days. At the end of experiment, the animals were slaughtered and carcass dressing, commercial cuts and meat composition and quality were evaluated. The meat quality was evaluated by color, tenderness and chemistry composition (moisture, fat, protein and minerals). The results showed no differences among treatments concerning parameters studied (P>0,05). Therefore, bakery waste can be considered an alternative source for feeding growing steers, when compared with corn.The effects of the addition of bakery waste (BW) replacing corn in the diet of Holstein steers was studied on carcass dressing and meat quality. Four treatments were applied, respectively, 0%, 10%, 20% and 30% of bakery waste replacing corn in the concentrated mixture. The animals were fed with complete pelleted mixtures, with 30% of Coast-cross hay (Cynodon dactylon L.) as roughage. A randomized block design with four treatments and five repetitions, total of 20 animals, was used. The experiment began when the calves reached 90 kg of live weight and lasted for 120 days. At the end of experiment, the animals were slaughtered and carcass dressing, commercial cuts and meat composition and quality were evaluated. The meat quality was evaluated by color, tenderness and chemistry composition (moisture, fat, protein and minerals). The results showed no differences among treatments concerning parameters studied (P>0,05). Therefore, bakery waste can be considered an alternative source for feeding growing steers, when compared with corn.