Showing papers in "Revista Brasileira De Zootecnia in 2010"

Silage microbiology and its control through additives

Abstract: Ensiling is a method of preserving a moist crop. A moist crop can support the growth of a wide range of microorganisms, most of which will degrade the nutrient value to livestock. However, ensiling generally controls microbial activity by a combination of an anaerobic environment and a natural fermentation of sugars by lactic acid bacteria on the crop. This fermentation and the resulting low pH primarily suppress the growth of other anaerobic microorganisms. The fermentation can also inhibit yeasts, molds and aerobic bacteria, but the anaerobic environment is essential to preventing most of the spoilage microorganisms from growing. Inoculants have become the dominant additives for making silage. Homofermentative strains help guarantee a rapid suppression of anaerobic stains early in storage, increase dry matter recovery and have improved animal performance by means that we do not fully understand. Inoculants containing Lactobacillus buchneri, a heterofermentative species capable of fermenting lactic acid to acetic, are recent additives. The added acetic acid inhibits yeast and mold growth, increasing aerobic stability of silages at feeding.

The role of oxidative stress in small ruminants' health and production

Abstract: This paper examines the role that oxidative stress plays in small ruminant medicine. We will examine how redox homeostasis is involved in some physiological functions and we will discuss the implications of the impairment of oxidative status on small ruminant health and production.

Nutritional management to improve sheep and goat performances in semiarid regions

Abstract: Small ruminant production is the main source of income of farmers living in arid and semiarid regions. Sheep and goats raised in these areas are generally confronted with severe nutritional deficits during food scarcity period which exacerbate disease and health problems and consequently low productive and reproductive performances. These areas are characterized by rainfall seasonality and scarcity resulting in a low fodder potential. Therefore, native rangelands are degrading due to overgrazing, high stocking rates and mismanagement. Options to improve small ruminant-based production systems include i) innovative technologies targeting the increase of feed resources availability, rumen manipulation using natural compounds to boost microbial activity, improving diets' quality, alleviation of feeding cost, and better control of livestock watering. Although this paper is focussing on the benefits from these technical options, we should bear in mind that i) the organization of local institutions for better adoption of these technologies and for protecting the main natural resources (rangelands and water) and ii) the participatory approach involving all partners concerned with the improvement of farmer's income and livelihood are key tools for promoting livestock sector in the target areas. A set of simple, inexpensive and environmentally friendly options that could ameliorate small ruminant production in the semiarid regions are discussed in this paper.

A piscicultura e o ambiente: o uso de alimentos ambientalmente corretos em piscicultura

Abstract: Although fish nutrition science is far from establishing general standards of nutritional requirements, the need for developing low impact feeds has long been included in the agenda of aquaculture's international scientific and business communities of. Not only is absolutely possible to formulate environmental friendly feeds, as it is necessary modeling the formulation of these feeds. However, it is necessary higher accuracy to develop species-specific formulations, considering interactions of the biology and nutritional physiology of the species with the feedstuffs and variations of abiotic environment. The knowledge on more than 200 species of commercially farmed fish is still incipient and fish production systems, in their most varied farming conditions, are set up in every possible ecological conditions. In this scenario, producing environmental friendly feeds is if not impossible, at least very, very difficult, depending on coordinated and positive action of producers, industry, regulatory agencies, and institutions of higher education and research to define the parameters needed to achieve this goal.

Brazilian scientific progress in pasture research during the first decade of XXI century

Abstract: This paper aims to discuss the scientific progress obtained in the past ten years in genetics and plant breeding, soil fertility and plant nutrition and the importance of target sward conditions for planning, controlling and recommending management grazing of tropical grasses. In addition, progress in crop-livestock integration systems and management alternatives for mitigation of greenhouse gas emission by beef cattle production systems, two very important areas related to sustainable production systems, will also be discussed.

Genetics and breeding of sheep in Brazil

Abstract: Studies in genetics and breeding of sheep in Brazil have increased significantly in recent years. These involve research in characterization, breeding and crossing sheep using new technologies available incorporating both classical quantitative and molecular genetics. Improvements in statistical techniques, computational resources as well as analysis of DNA and gaps in present knowledge and opportunities for possible research are pointed out. There is a need for greater interaction between various groups working in the country as well as interactions with other disciplines such as Geographical Information Systems, Statistics, Bioinformatics, as well as biological studies such as physiology and proteomics. Genetica e melhoramento de ovinos no Brasil RESUMO - Estudos em genetica e melhoramento de ovinos no Brasil tem aumentado significativamente nos ultimos anos. Estes envolvem pesquisa em caracterizacao, criacao e cruzamento de ovinos utilizando as novas tecnologias disponiveis, incorporando tanto a genetica quantitativa classica e molecular. Sao abordadas sugestoes para melhorias nas tecnicas de estatistica, nos recursos computacionais, bem como na analise de DNA e nas lacunas no conhecimento atual e possibilidades de possiveis investigacoes. Ha uma necessidade de maior interacao entre varios grupos de trabalho no pais, bem como as interacoes com outras disciplinas, como Sistemas de Informacao Geografica, Estatistica, Bioinformatica, bem como estudos biologicos, como fisiologia e proteomica.

Water and small ruminant production

Abstract: Water is a nutrient of extreme importance for animals and must be considered vital in any rearing phase. The increasing scarcity of this precious natural resource has concerned different segments of society in order to find solutions for rational and sustainable use of this nutrient. Small ruminants, especially sheep and goats, have social and economic importance due to their great ability in adapting to adverse environmental conditions and using water efficiently. Thus, they might be a good alternative to mitigate the climate change effects and to generate foreign exchange and improving life condition in many places of the world. The concept of water productivity for livestock production is relatively new and there are few studies in the world, especially in Brazil. More researches and new technologies for water use in livestock production are indispensable.

Composição química, fracionamento de carboidratos e proteínas e digestibilidade in vitro de forrageiras tropicais em diferentes idades de corte

Abstract: Objetivou-se avaliar o valor nutritivo de tres especies forrageiras tropicais: capim-tanzânia (Panicum maximum Jacq.), capim-marandu (Brachiaria brizantha) e capim-tifton 85 (Cynodon spp), em duas epocas do ano (janeiro-marco e abril-junho) e em tres idades de rebrota (28, 35 e 42 dias), por meio da composicao quimica, do fracionamento de proteinas e carboidratos e da digestibilidade in vitro da materia seca (DIVMS) e da materia orgânica (DIVMO). O capim-marandu destacou-se no periodo de janeiro-marco, com menores conteudos de parede celular e fracao B2 dos carboidratos e maiores valores de proteina bruta, fracao A + B1, DIVMS e DIVMO, em comparacao aos capins tanzânia e tifton 85, independentemente da idade de corte. O aumento da concentracao de parede celular em detrimento ao conteudo celular com o avanco da maturidade das plantas foi evidente no capim-marandu no periodo de janeiro-marco, quando foram observados maior valor da fracao B2, maior conteudo de fibra em detergente neutro (FDN) e menor concentracao da fracao carboidratos nao-fibrosos. No periodo de abril-junho, a composicao em parede celular nao apresentou diferencas evidentes com aumento da idade, devido as condicoes ambientais observadas. O capim-tanzânia apresenta, de modo geral, baixos valores de parede celular e altos valores de carboidratos nao-fibrosos, DIVMS e DIVMO nesse periodo, seguido pelos capins marandu e tifton 85, respectivamente.

Nutrition, microbiota, and endotoxin-related diseases in dairy cows

Abstract: In this review article we present an overall summary of the role that high-grain/low forage diets have on rumen composition of microbiota and how changes in the diet affect the release of bacterial cell wall components that are toxic to the host. One of these toxic compounds is lipopolysaccharide or endotoxin, a component of the outer membrane of all Gram-negative bacteria. Moreover, data are provided that support the concept that endotoxin translocates into the blood circulation and show that rumen endotoxin is associated with multiple perturbations of blood variables related to carbohydrate, lipid, and mineral metabolism. In addition, endotoxin induces a general, nonspecific immune response known as acute phase response. We also pinpoint the fact that high-grain diets are associated with distinct clusters of plasma metabolites and immune variables suggesting that changing cereal grain to forage ratio in the diet is very important for the health of dairy cattle. Furthermore, we provide information that support the concept that endotoxin is involved in multiple metabolic diseases such as fatty liver, milk fever, laminitis, retained placenta, displaced abomasum, and downer cow syndrome. More research is warranted to clarify the mechanisms by which nutrition, microbiota, and endotoxin contribute to development of metabolic diseases in dairy cattle. It is concluded that besides the aforementioned causal agents other compounds generated in the gastrointestinal tract such as lipoteichoic acid or methylated amines might be involved in the etiology of several metabolic diseases.

Potential of Caatinga forage plants in ruminant feeding

Abstract: Caatinga is the most important biome for the livestock in the Brazilian semi-arid region. This review paper aimed to present information on different forage aspects of caatinga vegetation for ruminant feeding. Caatinga vegetation is formed mainly by shrubs and small trees, usually presenting thorns, deciduous leaves, and leaf abscission occurring frequently at the onset of the dry season. Additional components of the botanical composition in this biome includes the families cactaceae, bromeliaceae, and a herbaceous component formed by grasses, legumes, and forbs, often presenting annual cycle. Quantitative information of caatinga vegetation is scarce in the literature, mainly for the herbaceous stratum. Methodological aspects such as lack of standardization across evaluations make comparison regarding forage potential of caatinga plant species difficult. Index species must be identified within each caatinga type. Quantitative aspects of biological N2 fixation by caatinga species have not been extensively studied. Regarding forage nutritive value, it is necessary to study N availability for ruminants in caatinga plants, since large proportion of this element may bind to fiber components (ADIN). Manipulation of caatinga vegetation is an alternative to change forage quantity and quality for grazing animals, affecting their performance as a result. Studies measuring qualitative and quantitative variability of native forage resources from caatinga are mandatory in order to improve animal feeding management, with the ultimate goal of creating sustainable animal production based on caatinga vegetation.

Alternatives for methane emission mitigation in livestock systems

Abstract: Human activities are contributing to Global Climate Change through the production of Green House Gases (GHG), which result in increased air, land and ocean temperatures and extreme changes in precipitation in regions of low and high rainfall. The most important GHG's are carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). It is estimated that 18 % of the annual GHG emissions come from different types of livestock and that 37% of CH4, with higher global warming potential (23) relative to CO2 (1), comes from fermentation processes in ruminants. It is possible that in the future beef and milk exports from producing countries is subject to bans if cattle systems do not comply with measures to reduce GHG. There are several alternatives available and being researched to reduce enteric CH4 emissions from cattle that range from manipulating diet composition, supplementing feed additives (i.e. ionophores, organic acids, halogenated compounds, oils) and selection of forage plants of high quality and containing secondary metabolites (i.e. tannins and saponins) to animal breeding, immunization and genetic transformation of rumen microorganisms. Results show that inhibition of enteric CH4 emission is possible through the use of ionophores, organic acids and oils. The use of ionophores can result in resistance of rumen microbes and as a result the effect is short term. The high cost of organic acids makes it unlikely that there direct supplementation in ruminant diets is economically viable. However, organic acids are present at relatively high concentrations in the leaf tissue of plants and attempts should be made to select and breed forages with higher levels of these compounds. It is argued that a more efficient strategy to reduce enteric CH4 in ruminants is through selection of grasses of high quality (i.e. high concentration of water soluble carbohydrates), of forage legumes containing secondary metabolites like tannins and of fruits/plants containing saponins, provided that they do not affect intake and digestibility. Improved nutrition of cattle through feeding high quality forages can result in high animal performance and in reductions of CH4 emitted per unit of dry matter intake and per unit of product.

The use of legume and herb forage species to create high performance pastures for sheep and cattle grazing systems

Abstract: - Sheep and cattle farmers need pastoral systems that are more productive and environmentally sustainableThe role that high feeding value herb and legume forage species can play in the farms of the future is highlighted It is shownthat species such as chicory ( Cichorium intybus ), plantain ( Plantago lanceolata ), red clover ( Trifolium pratense ) and whiteclover (T repens ) can provide live weight gains in lambs that are 70% greater than those from perennial ryegrass ( Loliumperenne) based pastures A case for replicated experiments that examine the value of whole technology packages based onherb and legume species, rather than component research, is madeKey Words: chicory, feeding value, lamb growth, plantain, red clover, white clover Uso de leguminosas e forrageiras herbaceas para criar pastos de altodesempenho para sistema de pastejo de ovinos e bovinos RESUMO - Produtores de ovinos e bovinos necessitam de sistemas pastoris mais produtivos e ambientalmentesustentaveis As especies forrageiras herbaceas e leguminosas de alto valor nutricional podem ter um papel destacado no futurodesses produtores Foi demonstrado que especies tais como a chicoria (

Perdas e valor nutritivo de silagens de milho, sorgo-sudão, sorgo forrageiro e girassol

Abstract: The objective of this study was to assess the losses and nutritional value of silages of different forage crops (corn, Sudan sorghum, forage sorghum and sunflower) ensiled at the ideal time for each crop. A randomized complete design was used, with four forage crops and five replications. The forages were ensiled in PVC silos, 50 cm high and 10 cm in diameter, equipped with a Bunsen valve, that were stored for 60 days. The losses through gases and effluent were assessed for difference in weight before and after ensilaging. The losses by gases were relatively small compared with the losses by effluent. The corn silage stood out because it presented smaller losses, while the sunflower and Sudan sorghum presented greater losses by effluent. The Sudan sorghum silage presents the lowest nutritional value, due to the greater contents of the fibrous fractions, while the corn silage stand out positively because of its nutritional value.

Study of relations among age at first calving, average weight gains and weights from weaning to maturity in Nellore cattle

Abstract: Data from 23,120 Nellore animals were used to estimate genetic parameters for age at first calving, average gains from weaning to yearling and from yearling to after yearling, weaning weight, yearling weight, after yearling weight and weight at 2 and 5 years of age. Animal models were fitted by Restricted Maximum likelihood Method. Estimate heritability for age at first calving, weaning to yearling weight gain, yearling to after yearling weight gain, weight at weaning, yearling weight, after yearling weight and weight from 2 to 5 years of age were 0.17 ± 0.01; 0.23 ± 0.03; 0.25 ± 0.03; 0.28 ± 0.02; 0.26 ± 0.03; 0.30 ± 0.03; 0.32 ± 0.02 and 0.36 ± 0.04, respectively. The genetic correlation estimates between age at first calving and weight traits ranged from -0.26 to -0.14. The genetic correlation estimates between age at first calving and average gains were also negative, but higher (-0.29 and -0.32). In general, these results indicate that selection for average gains will promote changes in age at first calving and female mature weight. Improvement in reproductive performance could be obtained with the inclusion of the age at first calving in the selection index.

Comportamento ingestivo de tourinhos terminados em confinamento, alimentados com diferentes níveis de concentrado na dieta

Abstract: This study was developed to evaluate the ingestive behavior of beef cattle finished in feedlots with different concentrate levels in the diet. Sixteen bulls fed 22, 40, 59, or 79% of concentrate in the diet were assigned to a complete randomized design, with four replicates each. The supplied diets were isoproteic and the roughage used was corn silage. Data collection was carried out during the finishing period, with a total of six days. The time given to food intake, rumination, the number of bouts per meal and neutral detergent fiber rumination efficiency decreased linearly as the concentrate levels in the diet increased. Idle time increased linearly accordingly to the increment of concentrate in the diet. The animals have greater feed intake and rumination efficiency when fed higher levels of concentrate (79%).

Evaluation of elephant grass silage with the addition of cassava scrapings

Abstract: The objective of this experiment was to evaluate the effects of adding cassava scrapings on gas and effluent losses, dry matter recovery, pH, contents of N-NH3, organic acids and volatile fatty acids and the bromatological composition of elephant grass silages. It was used a randomized complete design, with four levels of cassava scrapings (0, 7, 15 or 30% natural matter) each one with four replications per level. The grass was cut at 50 days of regrowth and ensiled in 15-L silos, equipped with a Bunsen valve to allow gas outflow. The gas losses decreased quadratically with the addition of cassava scrapings, whereas effluent losses decreased linearly. Dry matter recovery increased quadratically with the addition of cassava scrapings. Dry matter (DM) concentration increased but crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and hemicellulose (HEM) decreased linearly with the addition of cassava scrapings. The pH value and lactic acid concentration increased quadratically with the addition of cassava scrapings. Contents of N-NH3 and butyric acid decreased quadratically with the addition of cassava scrapings, whereas acetic acid content decreased linearly. Addition of cassava scrapings reduced gas and effluent losses and improved the fermentation profile of elephant grass silages and the level of 7% already ensures this improvement.

Conforto térmico e desempenho de pintos de corte submetidos a diferentes sistemas de aquecimento no período de inverno

Abstract: The objective of this study was to evaluate the effect of different poultry house heating systems on the thermal comfort and performance of broiler chicks during the winter period, in the southern region of Brazil. Three buildings were used, each containing 17,700 broiler chickens (Cobb), during two complete productive cycles. Three heating systems were evaluated: furnace with indirect air heating; infrared heater and radiant experimental "drum" system with an infrared supplemental heating system. In order to evaluate the thermal environment and animal performance, a randomized block experimental design with three heating system was used, in two complete productive cycles. In the first two weeks after birth, the radiant experimental "drum" system is the most efficient in maintaining the air temperature and relative humidity in thermal comfort condition of the broiler chicks and, consequently, result in the best results of weigh gain, dietary conversion and efficient production.

Desempenho e conversão alimentar de novilhos de corte em capim-tanzânia submetido a duas intensidades de pastejo sob lotação rotativa

Abstract: O experimento foi realizado para avaliar o valor nutritivo da forragem, o desempenho e a conversao alimentar de novilhos em pastos de Panicum maximum Jacq. cv. Tanzânia submetidos a duas intensidades de pastejo rotativo (residuos de 25 e 50 cm), associadas a intervalo de pastejo correspondente ao tempo necessario para que o dossel forrageiro interceptasse 95% da luz incidente durante a rebrotacao. O delineamento experimental utilizado foi o de blocos completos casualizados, com duas repeticoes. Foram avaliados a altura do dossel pre-pastejo, os intervalos de pastejo, o ganho de peso individual, a conversao alimentar, a taxa de lotacao e o ganho de peso por unidade de area. Pastos manejados com o residuo 50 cm apresentaram maior numero de ciclos de pastejo em relacao aqueles manejados com residuo de 25 cm. O maior ganho de peso medio diario foi registrado nos pastos manejados com 50 cm de residuo (801 g/dia) em relacao aqueles manejados com de 25 cm de residuo (664 g/dia). Em contrapartida, a taxa de lotacao foi mais alta nos pastos manejados com o residuo 25 cm, fazendo com que os ganhos de peso por unidade de area fossem 601 e 559 kg/ha para os residuos de 25 e 50 cm, respectivamente. O manejo do pasto visando altura de residuo de 25 cm proporciona maiores ganhos de peso por unidade de area e maior uniformidade de producao e o residuo de 50 cm promove maior ganho individual e maior numero de ciclos de pastejo.

Estimativas de parâmetros genéticos para os escores visuais e suas associações com peso corporal em bovinos de corte

Abstract: Foram avaliados 27.523 e 21.746 registros das caracteristicas conformacao, precocidade e musculatura a desmana e ao sobreano, respectivamente, para estimar os componentes de covariância entre estas caracteristicas e entre estas e os pesos corporais medidos nas mesmas idades. Para as analises dos dados, foram empregados modelos animais com efeitos geneticos direto e materno e efeito de ambiente permanente materno. Maxima verossimilhanca restrita foi empregada para estimar os parâmetros geneticos. As estimativas de herdabilidade dos escores a desmama foram 0,13; 0,25 e 0,23 para conformacao, precocidade e musculatura, respectivamente. As estimativas de herdabilidade dos escores visuais avaliados ao sobreano foram de maiores magnitudes (0,24; 0,32 e 0,27 para conformacao, precocidade e musculatura, respectivamente). As estimativas das correlacoes geneticas entre escores medidos as mesmas idades, considerando desmana e sobreano, foram 0,67 e 0,75 entre conformacao e precocidade; 0,61 e 0,71 entre conformacao e musculatura; 0,95 e 0,95 entre precocidade e musculatura. As correlacoes geneticas estimadas entre o peso corporal a desmama e conformacao, precocidade e musculatura, respectivamente, foram 0,97; 0,67 e 0, 62. As estimativas entre conformacao, precocidade, musculatura ao sobreano e o peso corporal foram 0,83; 0,59 e 0,58, respectivamente. Os resultados indicam que os escores visuais podem ser utilizados como criterios de selecao. Aumento nos pesos corporais deve ser esperado como resposta correlacionada a selecao para essas caracteristicas.

Feed extrusion process description

Abstract: The following work discusses the main features of feed extrusion process explaining the expected effects on the final product according to the raw material used as starch, protein, fat and fiber. The selection of processing equipments as feeder, preconditioner and extruder is discussed considering the involved costs and the probability of future expansion. Dryers are also essential in the extrusion process as it reduces the level of moisture in an extrusion cooked product. High moisture levels increase the water activity which favors the bacterial and mold growth so an overview of different kinds of dryers is considered. Guidelines for an economic prediction are shown to determine the potential for profit considering the input of raw material cost, energy cost and capital equipment cost as related to the extrusion module.

Intake and digestibility in cattle under grazing supplemented with nitrogenous compounds during dry season

Abstract: The objective of this work was to evaluate the effects of supplementation with nitrogenous compounds on intake and digestibility in cattle under grazing during dry season. It was used five Holstein × Zebu steers with average initial live weight of 236 kg, kept in five Brachiaria decumbens Stapf. paddocks (0.34 ha). The experiment was carried out according to a 5 × 5 Latin square design, with five supplementation levels and five experimental periods. The supplementation levels were the following: 0; 0.35; 0.70; 1.05, and 1.40 g of crude protein/kg live weight. A mixture of urea, ammonium sulfate and albumin (4.5:0.5:1.0, respectively) was used as nitrogen supplement. The average crude protein levels in the diet were 7.39; 8.92; 10.98; 12.55; and 13.62%, as dry matter basis, for the respective supplementation levels. Linear-response-plateau relationships were observed between intake estimates and diet crude protein levels. The linear-response-plateau pattern showed that intake was increased up to crude protein levels close to 9%, as dry matter basis. The estimates became unchangeable from this level. The total and ruminal digestibility coefficients of dry matter and neutral detergent fiber, and diet level of total digestible nutrients presented a positive linear pattern according to diet crude protein levels. The rumen ammonia nitrogen concentration was linearly increased by diet crude protein levels. This variable assumed the value of 8.00 mg/dL when the intake estimates reached the maximum values. Supplementation with nitrogen compounds in quantities that raise the crude protein content in the diet to levels close to 9% optimizes the use of low-quality forage by cattle under grazing.

Amino acid digestibility and poultry feed formulation: expression, limitations and application

Abstract: The nutritional value or quality of dietary proteins used for poultry feed formulation varies: amino acid availability is an important measure of protein quality. Determination of ileal digestibility values has become the preferred method for estimating amino acid availability. This review discusses the different approaches to the expression of digestibility results, including correction for endogenous loss and the derivatisation of standardised values. Sources of variation in values include, the assay protocol, anti-nutritional factors in feedstuffs and feed milling. Feed formulating with ileal digestibility values should allow higher dietary inclusion levels of protein feedstuffs of lower quality provided that values of different feedstuffs are additive, the age of the bird and the use of feed enzymes are considered. An Australian data set of "ileal digestible amino acid values in feedstuffs for poultry" that has recently be published is described. This overview is intended to stimulate interest in the generation and application of ileal digestibility as a method for estimating amino acid availability in poultry nutrition.

A tilapicultura e seus insumos, relações econômicas

Abstract: The Brazilian aquaculture is the second (Chile is the first one) in South American production, supported basically by production chains of shrimp and tilapia culture. Brazil produced, in 2007, 95691.0 tons of tilapia, representing 45% of the continental aquaculture. Aquaculture from small and medium producers has shown in recent years changes on farming systems. By the end of the 90s, it was based on semi-intensive ponds and dams. From the year 2000, tilapia culture in cages highlighted, especially in Union waters (large reservoirs and hydroelectric dams in the Northeast Region). This change led to changes in the production chain, because adequate inputs to the system is needed: special diets, genetic material compatible with the rearing phases and production flow, since the new system has a higher scale of production. The agro-industrial system of fish covers two distinct production systems: a fishery system (extraction) and aquaculture (production system). Some links in this system are shared by both systems, but food and genetic material are exclusive of aquaculture. Both systems interact with processing, distribution and marketing, and often compete with each other. Currently, Brazil has genetically improved strains, continuous process improvement and adaptation to our conditions. The activity of tilapia culture has increased through a process of professionalization, where the producer is closer to the used management and inputs. Today, producers can choose the input that best fits the management practices, but this is not a common practice when considering price.

Medidas biométricas obtidas in vivo e na carcaça de ovelhas de descarte em diferentes estágios fisiológicos

Abstract: RESUMO - Objetivou-se determinar as medidas in vivo e na carcaca de ovelhas de descarte abatidas em diferentes estagios fisiologicos, assim como as possiveis correlacoes entre essas medidas objetivas (in vivo e na carcaca) e o peso corporal ao abate e da carcaca fria. Foram utilizadas 21 ovelhas da raca Santa Ines, distribuidas nos seguintes estagios fisiologicos: OL = ovelhas mantidas por 60 dias em lactacao com seus cordeiros e abatidas um dia apos o desmame dos mesmos; OSC = ovelhas que foram mantidas por 60 dias em lactacao com seus respectivos cordeiros e mais um periodo aproximado de 30 dias sem os cordeiros e posteriormente abatidas; e ONP = ovelhas que permaneceram por 60 dias em confinamento e que nao pariram durante o ano. Nao se observou diferenca entre os estagios fisiologicos na maioria das caracteristicas medidas in vivo e na carcaca. O perimetro da garupa determinado na carcaca e o perimetro toracico, as larguras do peito e da garupa obtidos in vivo mostraram-se altamente correlacionados aos pesos corporal e de carcaca fria dos animais. Portanto, essas medidas podem auxiliar na determinacao do peso corporal de ovelhas em diferentes estagios fisiologicos.

Avaliação do uso de ventilação mínima em galpões avícolas e de sua influência no desempenho de aves de corte no período de inverno

Abstract: The objective of this work was to evaluate a system of minimal or hygienic ventilation and its influence on thermal comfort, air quality and broiler zootechnical performance of poultries raised during the winter. Two similar sheds were used, with 9,500 Cobb broiler chickens per shed, during a complete productive cycle. In one of the sheds, a positive ventilation system that met minimal need of air renovation, composed by three fans with flow of 300 m3/min, was installed on the ceiling parallel to the floor. The other shed was considered control and did not have a ventilation system. For the first two weeks of age of the broilers, temperature and air relative humidity differed, and the system with minimal ventilation showed the worst comfort conditions. Broilers kept in no ventilation system showed the best results for slaughter weight (with ventilation - 1.549; with no ventilation - 1.577 kg), food conversion (with ventilation - 1.63 kg/kg and with no ventilation - 1.59 kg/kg) and productive efficiency (with ventilation - 285 and without ventilation - 297). There were some differences for concentration of contaminant gases, which were lower in the system with minimal ventilation. The system with minimum ventilation, the way it was designed in the experiment, significantly decreases the temperature inside the poultry shed, compromising the thermal comfort and damaging animal performance. Although the system with minimum ventilation results in lower gas concentrations, none of systems promotes average concentration of carbon dioxide and carbon monoxide harmful to birds.

Extratos vegetais em dietas para frangos de corte

Abstract: - The trial was carried out to evaluate different blends of plants extracts in broilers diets. It was used 1,350broilers distributed in a randomized block design with six replicates and five diets, one without additive and the four others,each containing one of the following additives: 10 ppm of avilamycin; 200 ppm of a product containing essential oils ofcarnation, thyme, cinnamon and microencapsulated capsicum; 100 ppm of a product containing essential oils of syntheticcinnamaldehyde and carvacrol and capsicum oleoresin microencapsulated; 500 ppm of a commercial product containingeucalypt oil, essential oil of Chinese cinnamon, leaves of Chilene boldo and seeds of fenu-Greek at the initial phase and1200 ppm in the grower and finisher phases. Performance parameters were evaluated at 21 and 42 days of age and the carcasscharacteristics at 44 days of age. From 27 to 30 days of age, it was carried out the metabolism trial trough total excretacollection method and metabolizable energy and the crude protein digestibility of the diets were determined. The diets withplant extract blends had no significant effect on the performance when compared to diet without additives or diet withavilamycin. The lack of challenge in the experimental facilities and the use of diets with high digestibility ingredientsmight have contributed to broilers express all their potential making undetectable the improvement made by the inclusionof any of these additivies. Diets with plant extract blends promote performance similar to those obtained with dietscontaining avilamycin.Key Words: additives, carcass characteristics, metabolic assay, performance

Parâmetros físico-químicos e perfil de ácidos graxos da carne de bovinos Angus e Nelore terminados em pastagem

Abstract: Os objetivos neste trabalho foram avaliar as caracteristicas de qualidade da carne, a composicao centesimal e os componentes lipidicos (colesterol e acidos graxos) do musculo longissimus thoracis de bovinos Angus (n=30) e Nelore (n=30) aos 36 meses de idade e com peso medio de carcaca de 250 kg terminados em pastagem. Os resultados de pH, luminosidade, teor de vermelho e perda de peso na coccao foram similares entre grupos geneticos. Entretanto, a carne dos animais Angus apresentou maior teor de amarelo (4,87 e 4,04) e menor forca de cisalhamento (7,86 e 9,13 kg) em comparacao a dos animais Nelore. A composicao centesimal foi semelhante entre racas. O colesterol na carne dos bovinos Angus foi mais elevado que na dos Nelore (45,45 e 36,99 mg/100 g). Os acidos graxos C14:0, C14:1 cis 9, C18:1 trans, C18:2n-6, C18:2 cis 9, trans 11 (CLA), C18:3n-3, total de n-3 e o total de acidos graxos poliinsaturados foram mais elevados nos animais Nelore que nos Angus. Os totais de acidos graxos saturados e monoinsaturados, no entanto, foram semelhantes entre grupos. A razao n-6/n-3 foi menor nos animais Nelore (1,58) que nos Angus (1,88). Os grupos geneticos de bovinos terminados a pasto influenciam a forca de cisalhamento, o colesterol e o perfil de acidos graxos. Esse efeito e mais pronunciado nos acidos graxos poliinsaturados C18:1 trans, C18:2 cis 9, trans 11 e C18:3n-3, o que sugere uma possivel diferenca entre animais das racas Angus e Nelore no metabolismo da biohidrogenacao. Embora menos macia, a carne de animais Nelore e nutricionalmente mais saudavel que a de animais Angus, pois tem menores percentuais de colesterol e maiores quantidades de acidos graxos n-3, precursor do CLA (C18:1 trans) e CLA.

Variação anual de características morfológicas e da temperatura de superfície do pelame de vacas da raça Holandesa em ambiente semiárido

Abstract: This work aimed to study the annual variation of temperature of the coat surface and other traits of coat in Holstein cows managed in a tropical environment by separately considering black coat and white coat. It was measured the coat thickness (mm) characteristic, hair length (mm), hair number (hair/cm2) and coat surface temperature on 191 crossbred cows with 7/8 and 31/32 Holstein composition distributed in 3 herds in a semi-arid environment. Less dense coats with shorter, flattened hair occurred predominantly in March, a time coinciding to high levels of solar radiation. This type of coat shows low resistance to the flux of latent and sensitive heat through the skin, thus favoring heat loss. The black coat surface temperature was on average 4oC higher than that of the white one during all the year and its variation followed that of the mean radiant temperature. The models developed to predict the effective thermal conductivity of the coat must take these differences into account because the thermal gradient parallel to the skin surface is not negligible for Holstein cows under the sun in a tropical environment, as well as the other traits.

Desempenho, digestibilidade e balanço de nitrogênio em cordeiros alimentados com silagem de milho ou cana-de-açúcar e dois níveis de concentrado

Abstract: Utilizaram-se 32 cordeiros Ile de France, nao-castrados, alimentados com dietas contendo silagem de milho ou cana-de-acucar em duas relacoes volumoso:concentrado (60:40 ou 40:60). Os animais foram mantidos confinados individualmente com controle do alimento fornecido e das sobras e pesados semanalmente para determinacao do ganho de peso diario e da conversao alimentar. Simultaneamente, foram realizados ensaios de digestibilidade e metabolismo para determinacao do consumo e da digestibilidade dos nutrientes e do balanco de nitrogenio das dietas experimentais. O ganho de peso foi maior nos cordeiros alimentados com silagem de milho, de 294,6 g/dia, e com a relacao volumoso:concentrado 40:60, de 314,3 g/dia. A relacao volumoso:concentrado influenciou apenas os consumos de fibra em detergente neutro (FDN) e fibra em detergente acido (FDA) digestiveis, cujos maiores valores, de 125,26 e 48,97 g/dia, foram obtidos com a relacao volumoso:concentrado 60:40. Os cordeiros alimentados com silagem de milho apresentaram maior consumo de todos os nutrientes digestiveis, exceto proteina bruta (162,00 g/dia) e carboidratos nao-fibrosos (471,42 g/dia). As maiores digestibilidades de materia orgânica (80,34%) e carboidratos totais (80,71%) foram obtidas com a relacao 40:60 e as de materia seca (78,91%), proteina bruta (81,30%) e energia bruta (78,77%), nos cordeiros alimentados com cana-de-acucar. Os maiores valores de nitrogenio ingerido, absorvido e retido, de 32,6; 20,5 e 13,7 g/dia, respectivamente, foram observados com o fornecimento das dietas com 40% de volumoso. O tipo de volumoso influencia mais a digestibilidade dos nutrientes que sua proporcao na dieta.

Proteína e energia na alimentação de pacus criados em tanques-rede

Abstract: The aim of this study was to evaluate the performance of pacu (Piaractus mesopotamicus) raised in cages and fed diets containing levels of crude protein (CP) and digestible energy (DE). It was used 3.960 fish with an average initial weight of 293.38 ± 5.67 g, distributed in 18 net-ponds with 5 m3, with 220 fish per experimental unit (44 fish/m3) in a 3 × 2 factorial scheme composed of three levels of crude protein (25, 30 and 35%) and two levels of digestible energy (3,250 and 3,500 kcal/kg). Feeding was performed four times a day (9:00 a.m., 11:30 a.m., 2:00 p.m. and 5:00 p.m.) until apparent satiety of the animals. No differences were observed for weight gain, survival rate, apparent feed conversion and specific growing rate. Nevertheless, there was a difference on visceral fat deposition which was higher for animals fed ration with higher energy level. It was not observed influence of levels of protein and energy of the diet in contents of moisture, crude protein, mineral matter and lipids in the fish fillets, either. Rations containing 25% of crude protein and 3,250 kcal/kg of digestible energy promote better performance results.