Metabolismo e exigências de minerais em cabras gestantes

Foi avaliado o metabolismo e determinada as exigências de gestação de cálcio (Ca), fósforo (P), magnésio (Mg), sódio (Na) e potássio (K) em cabras leiteiras com gestação simples e gemelar. Ao todo foram utilizadas 100 cabras (PC 49,5 kg ± 8,9; ECC =2,6 ± 0,66) sendo 59 cabras da raça Saanen e 55 da raça Alpina. Para os estudos de metabolismo e cálculos de exigências nutricionais foi determinada a retenção dos minerais no corpo materno, no útero gravídeo e na glândula mamária através do método de abate comparativo, sendo que cabras gestantes foram abatidas em diferentes idades gestacionais. Adicionalmente amostras de sangue foram tomadas ao longo da gestação e foram determinadas as concentrações séricas de Ca, P, Mg, Na, K, Ca iônico e atividade da fosfatase alcalina. Foram realizados quatro ensaios de digestibilidade (por volta dos 50, 80, 110 e 145 dias de gestação). Os dados foram analisados como modelos mistos e as exigências de gestação foram determinadas através da equação de Gompertz. O número de fetos não foi decisivo para as mudanças no metabolismo mineral materno. O ganho de peso corporal materno e as suas retenções de Ca, P e Mg (g/kg) diminuíram com o avanço da gestação (P < 0,01). A retenção de todos os macro minerais no corpo materno (g/kg) das cabras Alpina foram maiores (P < 0,01) e seus fetos apresentaram maior deposição (mg/g) de Ca, P e Mg (P < 0,01). Quando submetida à restrição alimentar, a mãe realizou ajustes fisiológicos para evitar a diminuição da deposição mineral nos fetos, sendo que esta não foi prejudicada pelo nível de 20% de restrição alimentar. Entretanto com 40% de restrição, o desenvolvimento fetal foi comprometido, pois a prioridade de certos minerais como P, Na e K passou a ser do corpo materno. As exigências de minerais para gestação foram diferentes entres as raças estudadas...The metabolism was evaluated and determined the requirements for pregnancy of calcium (Ca), phosphorus (P), magnesium (Mg), sodium (Na) and potassium (K) in dairy goats with twin gestation and simple. Altogether 100 goats were used (PC 49.5 kg ± 8.9; ECC = 2.6 ± 0.66), 59 Saanen goats and 55 in Alpina. For studies of metabolism and nutritional requirements we determined the retention of minerals in the maternal body, uterus tissues, fetal fluid, fetuses and mammary gland by the method of comparative slaughter. The pregnant goats were slaughtered at different gestational ages. Further blood samples were taken throughout pregnancy and were determined serum concentrations of Ca, P, Mg, Na, K, Ca ionic and alkaline phosphatase activity. Four assays of digestibility were conducted (around 50, 80, 110 and 145 days of gestation). Data were analyzed as mixed models and the requirements for pregnancy was determined by Gompertz equation. The number of fetuses was not decisive for the changes in the mineral metabolism. The maternal body weight gain and its retention of Ca, Mg and P (g/kg) decreased with advancing gestation. The retention of all macrominerals in maternal body (g/kg) Alpina goats were higher and their fetuses showed higher deposition (mg/g) of Ca, Mg and P. When subjected to food restriction, the mother realized physiological adjustments to avoid the decrease of mineral deposition in the fetuses, and this was not affected by the level of 20% food restriction. However restriction with 40%, fetal development was compromised because the priority of certain minerals like P, Na and K became the maternal body. The mineral requirements for pregnancy were different between the breeds and types of gestation. Alpina goats have higher requirements of gestation Saanen goats. The maintenance requirements of pregnant goats is different from the recommended maintenance requirements for adult animals in genera

Uso da creatinina como indicador da excreção urinária em ovinos Creatinine use as an indicator of urinary excretion in ovines

Este estudo foi conduzido para determinar a excreção diária de creatinina e verificar o potencial de seu uso como indicador da produção urinária em ovinos. A medida da excreção urinária total de creatinina foi feita com base em dados e em amostras obtidas de quatro experimentos de digestibilidade conduzidos previamente com ovinos mantidos em gaiolas metabólicas. Em todos os experimentos, foi feita a coleta diária total de urina durante cinco dias em cada período experimental. Adicionalmente, em um dos experimentos, foram coletadas amostras de urina dos animais de duas em duas horas durante um período de 24 horas. A excreção total de creatinina (média de 660mg dia-1) foi diferente entre experimentos (P<0,01) e entre animais (P<0,01). A excreção diária como proporção do peso corporal (média 23,2mg kg-1 de peso vivo) foi diferente entre experimentos (P<0,01), mas semelhante entre animais, tratamentos e períodos (P>0,05). Por sua vez, a concentração de creatinina na urina foi diferente entre os experimentos (P<0,01), animais (P<0,01), períodos (P<0,05) e também nos diferentes horários de um período de 24 horas (P<0,01). A estimativa da produção urinária dos animais, com base na concentração de creatinina em amostras pontuais de urina, pode ser confiável somente se, em pelo menos um animal representativo de um grupo experimental, for realizada coleta total de urina para medida de excreção média desse metabólito por unidade de peso corporal. Além disso, amostras pontuais de urina devem ser coletadas em diferentes horários para constituir uma amostra composta representativa de um ciclo de 24 horas.<br>This study was carried out to evaluate the use of creatinine as an indicator of urinary production in sheep. Total creatinine urinary excretion was determined based on data and samples collected from four digestibility experiments previously conducted with lambs maintained in metabolic cages. In all experiments total urinary production was collected during five days in each animal and experimental period. Additionally, in one experiment, urine samples were taken at intervals of two hours during a 24 hours period. Total excretion of creatinine (mean of 660mg day-1) was different among experiments (P<0.01) and animals (P<0.01). The daily excretion as proportion of body weight (mean of 23,2mg kg-1 live weight) was different only among experiments (P<0.01), but was similar among the animals and periods and treatments (P>0.05). In the other hand, the urinary concentration of creatinine was different among experiments (P<0.01), animals (P<0.01) and periods (P<0.05). There were also differences among sampling times through a 24 hours period (P<0.01). The estimate of urinary production based on urinary concentrations of creatinine in spot samples, may be reliable only if, at least in one animal, representative of experimental group, total urine collection be carried out to measure the mean daily excretion of creatinine relative to body weigh. Moreover, spot samples should be collected in different times to constitute a composite sample representative of a 24 hours period

Effects of supplementation on production of beef cattle grazing tropical pastures in Brazil during the wet and dry seasons: a meta-analysis

A meta-analysis was undertaken to examine the effects of different supplementation strategies on production of beef cattle grazing tropical pastures during the wet and dry seasons in Brazil. The database was built with 132 studies published from 1999 to 2010, which accounted for 6,275 individual animals. The supplements assessed were classified into three groups: energy supplement containing 1.0% BW of energetic supplement in the wet season had the greatest gain per hectare (GPH; 8.16 kg/ha per day) and daily stocking rate (DSR; 2045 kg BW/ha/day). In the dry season, protein supplementation at rates >0.5% BW provided higher GPH (on average 2.33 kg/ha per day). Neither level nor type of supplement altered the DSR in the dry season (on average 883 kg/ha per day). Estimated regression showed that the ADG of beef cattle increased by 0.308 kg for each 1% of supplement intake. Increased supplementation intake by beef cattle grazing tropical pastures resulted in greater ADG in the warm season, whereas offering energy supplementation at rates >1.0% BW during the wet season as well as protein supplementation at rates >0.5% BW during the dry season increased gain per are

Wasted cabbage (Brassica oleracea) silages treated with different levels of ground corn andsilage inoculant

Our objective was to evaluate the chemical composition, fermentation profile, and aerobic stability of cabbage silages treated with ground corn and inoculant. The evaluated treatments were: addition of 200, 300, 400, 500, and 600 g of ground corn per kilogram of cabbage (fresh matter basis), with or without a bacterial inoculant composed of Lactobacillus plantarumand Pediococcus pentosaceus. As expected, ground corn additions increased the dry matter (DM) content of cabbage silage, and high values were observed for the highest level of addition (540 g kg&#8722;1). Conversely, the crude protein, neutral detergent fiber, acid detergent fiber, and lignin contents decreased with ground corn additions. The in vitro dry matter digestibility coefficients increased slightly with ground corn additions, but all cabbage silages had digestibility higher than 740 g kg&#8722;1 of DM. In the fermentation process, the pH values of cabbage silages increased linearly because of the high levels of ground corn addition. Cabbage ensiled with 200 and 300 g kg&#8722;1 of ground corn had high ammonia N production and fermentative losses (effluent and gas). Cabbage silage treated with 600 g kg&#8722;1 of ground corn had lower maximum pH values during aerobic exposure, but all silages had constant temperature during aerobic exposure. The ensiling of wasted cabbage is possible and we recommend the application of 400 g kg&#8722;1ground corn to improve the silage quality, whereas the use of the inoculant is unnecessary

Fluxo portal e visceral líquido de metabólitos em ovinos alimentados com feno de capim-arroz cortado com diferentes idades de rebrota

Foram conduzidos dois ensaios para medir os fluxos portal e visceral total de metabólitos em ovinos (peso vivo (PV) médio de 35 ± 3 kg) recebendo feno de capim-arroz (Echinochloa sp.) cortado aos 32, 46, 72 ou 90 dias de rebrota. Um dos ensaios foi realizado em quadrado latino 4 × 4 (ensaio 1) para avaliação dos quatro fenos e outro em quadrado latino 3 × 3 (ensaio 2), sem o feno do capim cortado aos 32 dias de rebrota. Os animais foram implantados com cateteres permanentes nas veias mesentérica e hepática. Sangue arterial foi acessado através de cateteres temporários na carótida. O fluxo de sangue portal e visceral foi estimado com base na diluição de paraminohipurato infundido continuamente em uma veia mesentérica. Na refeição prévia às amostragens, o consumo de matéria orgânica (MO) total e digestível não foi afetado, mas o consumo de nitrogênio total e digestível diminuiu linearmente com o aumento da idade de rebrota do capim-arroz em ambos os ensaios. Os fluxos de sangue portal e visceral, o fluxo visceral líquido de glicose, uréia e aminoácidos e o fluxo portal líquido de glicose e uréia não foram afetados pela idade de rebrota da forrageira. Os fluxos portais de aminoácidos e amônia foram maiores nos animais que consumiram o feno de 46 dias e maior quantidade de nitrogênio digestível. A maior parte dos nutrientes absorvidos pelos ovinos consumindo feno de capim-arroz foi metabolizada pelo sistema visceral, de modo que a disponibilidade de aminoácidos e de glicose aos tecidos periféricos representou somente pequena proporção do nitrogênio ou da matéria orgânica ingerida. Em geral, o metabolismo visceral dos animais não foi afetado pela idade de rebrota da forrageira

Replacement of aruana grass by gliricidia (Gliricidia sepium) on silage quality

Our objective was to investigate the effect of the replacement of aruana grass by gliricidia on the fermentative losses, chemical composition, and aerobic stability of silages. For ensiling, whole-crop aruana grass (75 d of growth) was chopped (275 g kg-1 dry matter - DM) and ensiled alone or associated with gliricidia (270 g kg-1 DM; 150 d of growth). For gliricidia, we used only the leaves and stalks to ensile. The evaluated treatments were different ratios of aruana grass to gliricidia (100:0, 75:25, 50:50, 25:75, and 0:100), with four replicates (mini-silos). The silage composed only of gliricidia exhibited a lower pH than the other silages. Dry matter recovery was not affected by the treatments, although effluent losses were affected. The replacement of aruana grass by gliricidia 50% at ensiling resulted in a higher lactic acid bacteria count. The aruana grass silages displayed lower protein contents and a higher neutral detergent fiber content than the gliricidia silages after 40 d of fermentation. Consequently, the silage consisting of 100% gliricidia showed higher in vitro DM digestibility, presenting an increase of 8.13% after 40 d of fermentation compared with 100% of aruana grass silage. After silo opening, the gliricidia silage was very stable (>72 h). The low quality of aruana grass silage is improved by replacing this grass with significant amounts of gliricidia (approximately 75%)

CHEMICAL COMPOSITION, DIGESTIBILITY AND AEROBIC STABILITY OF CORN SILAGES HARVESTED AT DIFFERENT MATURITY STAGES

The objective of this study was to evaluate the effect of corn plant harvested in diferente ma-turity stages on the chemical composition, digestibility and aerobic stability of silages. The corn used in the study was the hybrid BM3061 harvested after 114, 121, 126, 133 and 140 days of sowing at five maturity stag-es based on the advancement of the grain milk line (early dent (ED), 1/3 of milk line (ML), 1/2 ML, 2/3 ML and black layer (BL)). A variation from 242.7 to 377.4 g of dry matter (DM) kg-1as fed was observed between the ED and BL stages; however, the measurements performed in this study did not exhibited major changes in the composition of these silages. The silages produced with plants that were harvested at the 1/2 ML, 2/3 ML and BL stages showed lower DM loss during the fermentative process. The silages produced with plants that were harvested at the ED and 1/3 ML stages showed higher in vitro organic matter digestibility (IVOMD) (0.584 and 0.631 g g-1 of OM, respectively). The corn silages produced at the maturity stage of 2/3 ML showed a higher aerobic stability (104 hours) during the aerobic exposure. The 1/3 and 2/3 ML maturity stages seem to be the best harvest stages for the production of corn silage in tropical climates