The objective of this study was to assess the agronomic, morphogenic and structural characteristics of tropical forage grasses during the establishment phase and throughout the second year in northeast Brazil. The treatments included 9 grasses: Brachiaria humidicola (koronivia grass), Brachiaria hybrid cv. Mulato, Brachiaria brizantha cvv. Piatã, Xaraés and Marandu, Brachiaria ruziziensis (ruzi grass), Brachiaria decumbens (signal grass), Panicum hybrid cv. Massai and Andropogon gayanus (gamba grass). The grasses were planted in a randomized complete block design with 4 replications. The following parameters were measured: total forage production, leaf:stem ratio, tiller population density, number of dead tillers, leaf emergence rate, phyllochron, leaf elongation rate, stem elongation rate, rate of leaf senescence, final length of leaf blade and life-span of leaves. In the establishment year, cv. Mulato produced the highest forage yields, followed by cvv. Xaraés and Massai, with gamba grass and koronivia grass worst. In the second year, cvv. Mulato, Xaraés and Marandu, and gamba grass showed highest forage production, while cvv. Massai and Piatã produced the least. All grasses showed a marked drop in production during the dry season. Cultivar Massai consistently had the highest leaf:stem ratio. The morphogenic and structural characteristics differed according to cultivar and season of the year. In general, leaf emergence rate, leaf elongation rate, stem elongation rate, rate of leaf senescence, final length of the leaf blade, number of live leaves per tiller and density of living tillers were higher in the rainy season, while the phyllochron and life-span of leaves were higher in the dry season. The results of this research highlight the potential of the Brachiaria cultivars Mulato and Xaraés, gamba grass and Panicum cv. Massai in subhumid Maranhão, northeast Brazil. ResumenEl estudio se realizó en el nordeste de Brasil con el objetivo de evaluar las características agronómicas, morfogénicas y estructurales de 9 gramíneas forrajeras tropicales durante la fase de establecimiento y el primer año de producción. Los tratamientos incluyeron: Brachiaria humidicola, Brachiaria híbrido cv. Mulato, Brachiaria brizantha cvs. Piatã, Xaraés y Marandu, Brachiaria ruziziensis, Brachiaria decumbens, Panicum híbrido cv. Massai y Andropogon gayanus. Las gramíneas fueron sembradas en un diseño de bloques completos al azar con 4 repeticiones. Se midieron los parámetros siguientes: producción total de forraje; relación hoja:tallo; densidad populacional de rebrotes; número de rebrotes muertos; tasa de aparición foliar; filocrono; tasas de elongación de hojas y tallos; tasa de senescencia foliar; longitud final de la lámina foliar; y duración de la vida útil de las hojas. En el año de establecimiento, Brachiaria hí-brido cv. Mulato produjo los mayores rendimientos de forraje, seguido por B. brizantha cv. Xaraés y Panicum híbrido cv. Massai, siendo A. gayanus y B. humidicola los de peor desempeño. En el segundo año, los cvs. M...

Rev. Bras. Saúde Prod. Anim., Salvador, v.15, n.4, p.815-826 out./dez., 2014 Accumulation of forage and sward structure of Xaraés grass subjected to intensity of cuts

Thermal discomfort inside facilities is one of the factors responsible for low productivity of caprines in the Brazilian Northeast region, because inadequate weather conditions can cause elevated rectal temperature, increased respiratory rate, decreased food ingestion and reduced production. The present paper aimed to study the behavior of physiological thermoregulation of the animals (respiratory rate -RR and rectal temperature -RT) at four different times of the day (8 a.m., 11 a.m., 2 p.m. and 5 p.m.) and their relation to bioclimatic indexes (Temperature Humidity Index -THI, Black Globe Humidity Index -BGHI and Radiant Heat Load -RHL) in order to determine whether the type of covering used in the animals facilities (ceramic covering -CC, asbestos cement covering -AC and straw covering -SC) interferes with the physiology of thermoregulation. The time of data collection was related to the values of environmental and physiological variables. At 2 p.m. it was found the highest values of Radiant Heat Load on the three types of covering. The values of RT and RR were higher at 11 a.m. and 2 p.m., and the straw tile provided better thermal conditions of microclimate for the animals. The increased RR maintained the caprines homeothermy.

RESUMO Objetivou-se comparar os coeficientes alométricos (b) que descrevem o crescimento das partes e dos órgãos de codornas de corte mantidas em diferentes ambientes térmicos. Foram utilizadas 300 codornas distribuídas em delineamento inteiramente ao acaso, com dois tratamentos (ambiente climatizado, AC) com temperatura de 26ºC e ambiente sem climatização (ASC, 32oC) e seis repetições de 25 aves. Ajustaram-se equações alométricas em função do peso em jejum (PJ) para as variáveis: peso do peito (PPEI), coxa (PCX), sobrecoxa (PSCX), asa (PASA), coração (PCOR), fígado (PFÍG), moela (PMOE) e intestino (PINT). Para comparar os “b” das partes e dos órgãos das aves mantidas nos diferentes ambientes, realizaram-se testes de paralelismo. Não houve diferença entre os “b” em nenhuma das partes e dos órgãos das codornas mantidos no ambiente AC ou no ASC. Observou-se que os PPEI e os PSCX apresentaram crescimento heterogônico positivo (b>1), os PCX crescimento isogônico (b=1), os PASA e os órgãos crescimento heterogônico negativo (b<1) em relação ao PJ. Os “b” que descrevem o crescimento das partes e dos órgãos de codornas de corte mantidas nos diferentes ambientes não são influenciados. O peso do peito e o da sobrecoxa apresentaram crescimento tardio, a asa e os órgãos (coração, fígado, moela e intestino) crescimento precoce, e o peso da coxa apresentou crescimento proporcional em relação ao peso em jejum.