ABSTRACT The objective of the present study was to evaluate the effect of feed type, pH, and Cu and Zn concentration on Cu and Zn binding with different feedstuffs after in vitro incubation in water. For this purpose, six feedstuffs (wheat straw, grass hay, corn silage, dried distillers grains with solubles, ground corn, and soybean meal) were incubated in ultrapure water (pH≈6.4) with supplemental Cu concentrations equivalent to 0, 5, 10, 15, 20, 30, and 40 mg Cu/kg DM or supplemental Zn concentrations equivalent to 0, 15, 30, 45, 60, 90, and 120 mg Zn/kg DM for 48 h. This experiment was repeated; however, following the 48-h incubation in ultrapure water (pH≈6.4), samples were incubated for one additional hour at a fitted pH of 2.3. Following incubation, the indigestible residue was analyzed for the presence of Cu and Zn. Copper and zinc bind to other dietary constituents at a pH similar to that of the rumen, regardless of the type of feedstuffs (concentrate or roughage). However, in a pH condition similar to that of the abomasum, part of these bonds is broken. In these pH conditions, there is greater breakdown of bonds in concentrate feedstuffs than in roughages, regardless of the mineral analyzed. Comparing these minerals, zinc forms weaker bonds than copper.

Resumo Propósito do tema: Nos últimos anos o turismo residencial tem obtido uma atenção em Portugal e na região do Algarve. Ele foi identificado pelo plano nacional de turismo como um dos produtos estratégicos. No Algarve o seu peso é relevante para a dinâmica do turismo. Objetivo: Este estudo está focado na percepção dos gestores públicos quanto ao turismo residencial no Algarve, em particular os pontos fortes, pontos fracos, oportunidades e ameaças que este produto cria para o desenvolvimento da região. Metodologia e abordagem: O estudo utiliza uma abordagem descritiva e exploratória a partir de um questionário online realizado a todos os municípios do Algarve. O estudo centra-se na visão dos municípios como atores-chave envolvidos no desenvolvimento do mercado de turismo residencial. Resultados: Os resultados são úteis para entender as trajetórias do turismo residencial, apresentando informações úteis para estratégias futuras. Originalidade: Observou-se que os fatores econômicos têm influência direta nos pontos fortes e ameaças, enquanto as fraquezas são mais percebidas como aspectos sociais e ambientais e as oportunidades exigem articulação entre todas as dimensões, econômicas, sociais e ambientais.

Abstract Proposal: Second home tourism has been paid attention in Portugal, and especially in the Algarve region, in recent years. It was identified as one of the strategic products in the national tourism plan. In the Algarve, the second home market is important for tourism dynamics. Objective: This study focuses on public sector managers' perception of second home tourism in the Algarve, in particular on strengths, weaknesses, opportunities, and threats that this product brings to regional development. Methodological Design: The study uses a descriptive and exploratory approach with an online survey applied to all municipalities in the Algarve. Results: The results are helpful to understand second home tourism trajectories by presenting useful information for future strategies. Originality: We observed that economic factors directly influence strengths and threats; weaknesses are more related to social and environmental aspects, and opportunities are linked to all three dimensions, i.e. economic, social, and environmental.

Resumen Finalidad tema: a En los últimos años el turismo residencial ha obtenido una atención relevante en Portugal y en la región del Algarve. Ha sido identificado por el plan nacional de turismo como uno de los productos estratégicos. En el Algarve su peso es relevante para la dinámica del turismo. Meta: Este estudio se centra en la percepción de los gestores públicos en relación con el turismo residencial en el Algarve, en particular, las fuerzas, debilidades, oportunidades y amenazas que este producto genera para el desarrollo de la región. Metodología y el enfoque: El estudio utiliza un enfoque descriptivo y exploratorio con una encuesta online aplicada a todos los municipios del Algarve. El estudio se centra en la visión de los municipios como actores clave en el desarrollo del turismo residencial. Los resultados son útiles para comprensión de las trayectorias del turismo residencial, información útil para las estrategias futuras. Originalidad: Se observó que los factores económicos tienen una influencia directa sobre los puntos de fuerzas y amenazas, mientras que las debilidades son más percibidas como los aspectos sociales y ambientales y, al final, en las oportunidades existen vínculos entre todas las dimensiones, económicas, sociales y ambientales.

ABSTRACT This experiment was conducted to evaluate the degradation kinetics and microbial efficiency of beef cattle grazing on low-quality forage and receiving supplements with different levels of rumen undegradable protein (RUP). The animals grazed on palisade grass pasture solely or this pasture and supplement containing 40 or 60 g of RUP per 100 g of crude protein (CP). The degradation profiles of neutral detergent fiber, fiber carbohydrates, and neutral detergent insoluble protein were interpreted kinetically by using a decreasing logistic model. Treatments (no supplement, or RUP at 40 or 60 g−1 100 g CP) did not affect rumen fill; however, the increase in the indigestible fiber carbohydrate fraction that occurred at the expense of the digestible fiber carbohydrate fraction resulted in a greater rumen fill effect. The palisade grass showed a significant proportion of its nitrogen in the form of slowly degradable protein as neutral detergent insoluble protein, which amounted to 26 g per 100 g CP. Supplementation with 40 g of RUP per 100 g CP decresead the indigestible fraction of the low-quality forage. However, the absence of a rumen-fill effect demonstrates that the additional supply of nutrients contributes greatly to increasing growth efficiency and use of the available energy from the forage by the ruminal microorganisms.

ABSTRACT Ten Holstein-Zebu crossbred cows distributed into two simultaneous Latin squares (5 × 5) as a 2 × 2 factorial arrangement formed by chopped sugarcane or elephant grass silage, both with high or low protein degradability supplements and a corn silage as a control treatment, were compared using orthogonal contrasts. The studied variables were the performance, plasma concentrations of urea-N, glucose, and creatinine, urine-N and milk urea-N, and the nychthemeral variation in NH3-N in the rumen fluid of dairy cows. Nutrient intake, milk production, and milk composition were affected by the treatments. The total mixed ration containing elephant grass silage combined with rumen undegradable protein (RUP) provided balanced amounts of carbon and nitrogen in the rumen. This effect may explain the 18% increase in milk yield compared with the other treatments. The diurnal pattern of ruminal NH3-N was interpreted with a sinusoid model. In general, cows fed elephant grass silage exhibited higher concentrations of blood plasma and milk urea-N than animals fed sugarcane. The cows that consumed elephant grass silage with rumen degradable protein concentrate showed a higher milk urea-N compared with animals that consumed elephant grass silage with the RUP concentrate. The use of diets based on corn silage leads to a better use of nitrogen compounds because these diets resulted in lower levels of urea-N in the plasma, urine, and milk at the same level of milk production compared with diets containing elephant grass silage or chopped sugarcane as roughages. In sugarcane-based diets, even greater nitrogen losses in the urine are observed, despite the presence of readily fermentable carbohydrates in the diet.

ABSTRACT The objective of this study was to evaluate the intake and digestibility of silages containing pineapple pulp and coast-cross hay, with or without addition of urea, and the recovery of the markers chromium oxide (Cr2O3), indigestible neutral detergent fiber (iNDF), indigestible acid detergent fiber (iADF), and indigestible dry matter (iDM), in a digestibility assay, in sheep. Treatments were as follows: two levels of pineapple pulp (818 and 758 g kg−1) and two levels of urea (with and without urea), in a completely randomized design. Twelve sheep (three per treatment) were used, kept in metabolic cages. Fecal excreta were determined by total collection or estimated by using the markers. Marker samples were obtained in morning and afternoon collections, with mean concentrations obtained for both daily activities. The level of silage pulp did not affect intake, while addition of urea increased the intake of crude protein (CP), but did not influence the intakes of dry matter, organic matter, neutral detergent fiber, or acid detergent fiber. The digestibility coefficients of all afore-mentioned fractions increased with the increase in pulp, the same happening with the addition of urea. The internal marker with lowest variability among the internal markers was iADF, with mean values near 100%. Mean recovery of Cr2O3 was approximately 107%, but with lower variability among treatments. Inclusion of pineapple pulp in silage does not influence intake, while addition of urea only increases the intake of CP. The levels of pineapple pulp in silage with or without urea increase the digestibility of the silage. Indigestible acid detergent fiber is the marker with lowest variability of recovery, with mean recovery for the four silages used very close to 100%.

ABSTRACT The objective of this study was to simulate total dry matter intake and cost of diets optimized by nonlinear programming to meet the nutritional requirements of dairy does and growing doelings. The mathematical model was programmed in a Microsoft Excel(r) spreadsheet. Increasing values of body mass and average daily weight gain for growing doelings and increasing body mass values and milk yield for dairy does were used as inputs for optimizations. Three objective functions were considered: minimization of the dietary cost, dry matter intake maximization, and maximization of the efficiency of use of the ingested crude protein. To solve the proposed problems we used the Excel(r) Solver(r) algorithm. The Excel(r) Solver(r) was able to balance diets containing different objective functions and provided different spaces of feasible solutions. The best solutions are obtained by least-cost formulations; the other two objective functions, namely maximize dry matter intake and maximize crude protein use, do not produce favorable diets in terms of costs.

The objective of the present study was to evaluate the parameters related to the digestion of the fiber from silages of four corn hybrids (BX1280, SHS4070, 2B433, and DKB390) developed for silage production. Four rumen-cannulated castrated Holstein × Zebu crossbred cattle with approximate initial weight of 400 kg were distributed in a Latin square design. To determine the fiber passage rate and degradability, the techniques of chromium-mordant and in situ incubation of the neutral detergent fiber of the silages in nylon bags were used. The profiles of concentration of the marker in the feces were described by the generalized two-compartment model. Corn hybrid DKB390 is the most indicated for production of better-quality silages, because its fiber is more degradable in the rumen as compared with the other hybrids tested.