ABSTRACT Various studies have evaluated the use of electronic devices to automatically record the grazing behavior of dairy cows. Linking individual grazing behavior of dairy cows with the modifications in grazing behavior across the grazing session through the use of automatically registered indicators, would allow the development of decision-making tools in grazing management. The objective of the present study was to evaluate the use of the activity level (AL) recorded with an accelerometer during the grazing-down process of a pasture grazed by dairy cows as a possible criterion for decision-making related to grazing management. A completely randomized design was used to evaluate the AL of dairy cows in two contrasting pasture-based dairy production systems: A pasture-based system with high concentrate supplementation level and high herbage mass (HM), using high-yielding dairy cows (GRAZSUP), and a pasture-based system with minimal concentrate supplementation level and medium HM, using Holstein New Zealand strain (GRAZ). Pre-grazing HM was higher in GRAZSUP than in GRAZ (+750 kg DM ha-1), while forage removed was higher in GRAZ than in GRAZSUP (+1.9 kg DM cow-1 d-1). Although the production system influenced the characteristics of the pasture and the ingestive behavior of the dairy cows, when AL was evaluated as the proportion of the initial AL recorded at a time-point of the grazing-down process, there were no differences in each of the times evaluated. In conclusion, AL of grazing dairy cows was significantly affected during the grazing-down process, reflecting the modifications in grazing behavior across grazing session.

ABSTRACT: The objective of this study was to evaluate the inclusion of a brown seaweed additive (SWA; Macrocystis pyrifera) in the diet of grass-fed steers on carcass performance, beef quality, and nutrient composition. A total of 20 Holstein-Friesian steers were randomly distributed into two groups: Control group (a basal diet without supplementation of SWA) and SWA group (2%-SWA) with basal diet + 30 g/day/animal of SWA during the breeding phase (11 months) and 48 g/day/animal of SWA during the fattening phase (4 months). Steers fed with 2%-SWA were not different (P>0.05) in final body weight, carcass weight, carcass dressing, fat thickness, ribeye area, and marbling score than those from the Control group. Likewise, no effects of 2%-SWA supplementation were detected (P>0.05) for beef quality traits, glycolytic potential, or their metabolites (muscular glycogen, glycose+glucose-6-phosphate, and lactate), evaluated in longissimus lumborum (LL) samples. Sensory evaluation showed a slight preference for Control group samples rather than those from the 2%-SWA group (58.93% and 41.07%; P=0.06). Regarding, proximal composition, the inclusion of SWA only affected the total lipids present in the LL samples, which decreased significantly (P=0.01) in LL samples of grass-fed steers fed with 2%-SWA. The composition of macro (Ca, Na, Mg, P, and K) and micro (Mn, Fe, Cu, and Zn) minerals in LL samples were not affected (P>0.05) by the inclusion of SWA in the diet. The inclusion of the additive based on brown seaweed had not a detrimental effect on carcass performance, beef quality, and mineral content, however, it reduced the total lipids content in the LL muscle.

ABSTRACT Sugar-beet (Beta vulgaris L. subsp. vulgaris) pulp is a valuable by-product from the manufacture of beet sugar fresh which is normally preserved in the form of silage. The aim of the present research was to evaluate the effect of adding a homofermentative lactic acid bacteria silage additive during the ensiling period on fermentation and quality of sugar-beet (SB) pulp silage and the animal performance of dairy cows given restricted daily access to pasture. Twelve Holstein × Friesian crossbred cows were assigned to two groups according to milk yield, body weight, days in milk, parity and body condition score. Groups were randomly allocated to two treatments: silage of SB pulp without additive (control diet, SB) and silage of SB pulp with additive (SB+additive). The experiment was carried out in two periods of 28 d each. Once finished each period, cows were crossed for treatments. Chemical composition of SB silage was modified by the additive: Neutral detergent fiber (41.8% vs. 45.7% DM) and metabolizable energy (2.54 vs. 2.55 Mcal kg-1 DM) were greater and butyrate lower (0.34 vs. 4.10 mmol L-1) for SB+additive compared with SB. However, milk production (24.6 and 25.2 kg d-1) and composition were not affected (P > 0.05) by treatments. Similarly, rumen volatile fatty acids were similar between treatments. In conclusion, the use of homofermentative lactic acid additive on SB silage modified the chemical composition of silage and reduced the pasture intake, however, no changes in milk production and composition were detected.

ABSTRACT In temperate milk production systems, it is important to study the effect of grazing strategies in both the quantity and quality of the diet, resulting in potential impacts on animal metabolism. The aim was to evaluate the effect of timing of herbage allocation and herbage mass on blood indicators. Forty Holstein-Friesian cows were grouped according to milk production (24.7 ± 2.8 kg cow-1), body weight (580.6 ± 51.7 kg) and days in milk (74 ± 17.1 d). The groups were randomly allocated to one of four treatments: 1) L-AM, access to new herbage allocation after morning milking with herbage mass of 2000 kg DM ha-1; 2) L-PM; access to new herbage allocation after afternoon milking with herbage mass of 2000 kg DM ha-1; 3) H-AM; access to new herbage allocation after morning milking with herbage mass of 3000 kg DM ha-1; 4) H-PM; access to new herbage allocation after afternoon milking with herbage mass of 3000 kg DM ha-1. Milk production was only different for H-PM in 1.1 kg higher than L-PM. Urea in milk was affected by treatments, being 22% higher for L-AM than other treatments. ß-Hydroxybutyrate and blood urea concentrations were 47% and 30% higher, respectively, for AM compared to PM treatments. Plasma albumin concentration was lower for H-PM compared to other treatments at week 3 of blood sampling. PM treatments modify the herbage composition and animal metabolism, while combining it with a high herbage mass impacts positively in production and milk composition.

Abstract The cumulative effects of daily herbage allowance (DHA) restriction on pasture characteristics and the sustainability of pasture-based dairy systems were evaluated. Sixty-four dairy cows were randomly assigned to one of two grazing treatments (20 and 30 kg DM cow-1 day-1). Milk yield and pre- and post-grazing herbage mass were recorded for every grazing event. Botanical and chemical compositions of the pasture were evaluated. Low DHA increased the stocking rate by 0.7 cows ha-1 and consequently increased grazing efficiency from 41 to 47%. Daily herbage allowance restriction did not affect pasture characteristics or milk production per cow, but DHA restriction increased milk production per hectare (+27%). The results suggest that restriction on daily herbage allowance ensures a higher level of herbage utilization and milk output per ha than high DHA, without affecting pasture characteristics. Therefore, DHA might be a useful grazing management tool for improving the profitability and sustainability of grazing-based dairy systems.

Resumen El estudio evaluó el efecto acumulado de la restricción en la oferta diaria de pradera sobre las características de la pradera y sobre la sustentabilidad de los sistemas lecheros pastoriles. Se utilizaron 64 vacas lecheras que fueron asignadas aleatoriamente a dos tratamientos de pastoreo (20 y 30 kg MS vaca-1 día -1). En cada evento de pastoreo se registró la fitomasa de pre y post-pastoreo y la producción diaria de leche por vaca. Se evaluó la composición botánica y composición nutricional de la pradera. La baja oferta diaria de pradera aumentó la carga animal en 0,7 vacas ha-1 y consecuentemente aumentó la eficiencia de de pastoreo de 41 a 47%. La restricción en la oferta diaria de pradera, no modificó las características de la pradera ni la producción de leche por vaca, incrementando la producción de leche por hectárea en 27%. Los resultados de este estudio sugieren que la restricción en la oferta diaria de pradera por vaca, aumenta la eficiencia de utilización de la pradera y la producción de leche por hectárea respecto de una alta oferta de pradera sin afectar negativamente las características y sustentabilidad de la pradera. Por lo tanto, la oferta diaria de pradera puede ser una herramienta útil de manejo del pastoreo para mejorar la rentabilidad y sustentabilidad de los sistemas lecheros basados en pastoreo.

ABSTRACT In Chile, high moisture corn (Zea mays L. [HMC]) has been included mainly in diets for grazing dairy cows on pastures with high crude protein, and is an alternative that improves nutrients supply and rumen synchrony between energy and protein provided by the diet. In addition, supplementation with HMC results in an increase of fatty acids (FA) in milk, desirable for human health. The aim of this study was to evaluate the effect of herbage allowance (HA) and type of supplement on milk FA composition in grazing dairy cows during spring. Thirty-two multiparous Holstein-Friesian dairy cows (533 ± 71 kg BW; 53 ± 4 d in milk [DIM[ and milk yield 23.8 ± 4.2 kg d-1) were randomly assigned to four dietary treatments resulting from the combination of two HA levels (low 20 vs. moderate 30 kg DM cow1 d-1) and two types of supplements HMC and cracked wheat [Triticum aestivum L., CW]) offered at 3.5 kg DM cow-1 d-1. Total FA intake was greater for moderate HA (547.8 g d-1) than low HA (527.2 g d-1) (P < 0.05); but did not affect milk yield, milk constituents and milk FA composition (P > 0.05). Supplementation with HMC increased milk production by 2.3 kg d-1 compared with CW. Cows supplemented with HMC showed a greater intake of total FA (564 g d-1) and had greater concentrations of long-chain monounsaturated FA in milk (27.13 g 100 g-1) compared to cows supplemented with CW (511.0 g d-1 total FA intake and 25.39 g 100 g-1 in milk, respectively) (P < 0.05). It is concluded that grazing dairy cows supplemented with HMC during spring produced milk with higher concentrations of desirable FA, independently of the HA level.

ABSTRACT This study was conducted to evaluate the influence of management tools - daily pasture allowance and corn silage supplementation - during periods of forage shortage on the metabolism of dairy cows grazing low-mass pasture in temperate regions. Forty lactating Holstein cows were used during an experimental period of seventy days (April 15 to June 23, 2012). Blood metabolites and milk production were determined in fall-calving dairy cows grazing under two daily pasture allowances (PA) (moderate, 17 kg vs. high, 25 kg dry matter (DM)) and supplemented with corn silage (CS) (low, 4.5 kg vs. high, 9.0 kg DM). All cows received 3 kg DM of concentrate. Plasma concentrations of β-hydroxybutyrate (BHBA), non-esterified fatty acids (NEFA), and urea were determined using an automated spectrophotometer, and milk production was electronically measured at each milking time during the trial. The experimental design was completely randomized using a 2 × 2 factorial arrangement of treatments. The increase in daily PA decreased plasma concentrations of BHBA (0.91±0.36 vs. 1.12±0.43 mmol L−1), provided an increase in milk yield (23.18±3.26 vs. 21.99±3.37 kg d−1), and did not modify the concentrations of NEFA and urea. The increased CS supplementation increased mildly the plasma concentrations of BHBA (1.07±0.36 vs. 0.96±0.44 mmol L−1) and NEFA (92.77±54.14 vs. 92.77±55.31 µmol L−1), and decreased the concentrations of urea (4.08±1.40 vs. 4.64±1.30 mmol L−1), but did not change milk production. The positive effect of increasing PA was associated with a high herbage intake, while the lack of response to increasing CS supplementation was attributed to a high substitution of pasture intake (0.9 kg DM pasture/kg DM CS). Low corn silage supplementation is recommended.

Winter grazing provides a useful means for increasing the proportion of grazed herbage in the annual diet of dairy cows. This season is characterized by low herbage growth rate, low herbage allowance, and low herbage intake and hence greater needs for supplements to supply the requirements of lactating dairy cows. The aim of this study was to determine the influence of herbage allowance (HA) offered to autumn calving dairy cows grazing winter herbage on milk production, nutritional status, and grazing behavior. The study took 63 d using 32 multiparous Holstein-Friesian dairy cows. Prior to experimental treatment, milk production averaged 20.2 ± 1.7 kg d-1, body weight was 503 ± 19 kg, and days in milking were 103 ± 6. Experimental animals were randomly assigned to two treatments according to HA offered above ground level: low (17 kg DM cow-1 d-1) vs. high HA (25 kg DM cow¹ d¹). All cows were supplemented with grass silage supplying daily 6.25 and 4.6 kg DM of concentrate (concentrate commercial plus high corn moisture). Decreasing HA influenced positively milk production (+25%), milk protein (+20 kg), and milk fat (+17 kg) per hectare; however no effects on milk production per cow or energy metabolic status were observed in the cows. In conclusion, a low HA showed to be the most significant influencing factor on milk and milk solids production per hectare in dairy cows grazing restricted winter and supplemented with grass silage and concentrate; but no effect on the milk production per cow was found.

Salmonella serovars sampled from meat products in Southern Spain (Andalucía) during the period 2002-2007 were analyzed in this study. The serovars most frequently detected (in order) were Typhimurium, Enteritidis, Derby, Anatum and Rissen. Isolates (n = 43) were tested for sensitivity to biocides, including the quaternary ammonium compounds benzalkonium chloride (BC), cetrimide (CT) and hexadecylpyridinium chloride (HDP), and the bisphenols triclosan (TC) and hexachlorophene (CF). The minimum inhibitory concentration (MIC) for the quaternary ammonium compounds was in the range of 25 to 50 mg/L for most isolates, although a few isolates required much higher concentrations, up to 250 mg/L. Bisphenols showed higher inhibitory activity, with a MIC of 2.5 to 25 mg/L. A few isolates showed a “non-wildtype” MIC for TC of up to 250 mg/L. These results indicate a low incidence of tolerance towards quaternary ammonium compounds and triclosan among Salmonella from meats and meat products.

Esta investigación analiza la asociación entre el logro de aprendizaje en matemáticas, el estilo cognitivo en la dimensión dependencia-independencia de campo y la realidad aumentada (RA) en un ambiente virtual de aprendizaje. Para cumplir con el objetivo propuesto, se estructuró un estudio cuantitativo de tipo descriptivo-correlacional, con diseño de corte cuasiexperimental con dos grupos: uno experimental y otro de control con pretest y postest no equiparables. En el estudio participaron 83 estudiantes de la Escuela Colombiana de Carreras Industriales (ECCI) de Bogotá, del Programa de Ingeniería Industrial. Los resultados indican que el uso del paradigma de la realidad aumentada, implementada como estrategia de interacción natural con objetos digitales para el aprendizaje defunciones en varias variables, permitió obtener mejores resultados de forma efectiva y significativa en cuanto al logro de aprendizaje en estudiantes que cursaron la unidad didáctica Cálculo Vectorial, cuya tipología en la dimensión DIC es intermedia e independiente.

The association between learning achievement in mathematics, cognitive style in the field dependence/independence dimension (FDI), and augmented reality (RA) in a virtual learning environment is analyzed in this research. A quantitative descriptive/correlational study was structured to that end, with a quasi-experimental design and two groups: one experimental and the other a control group with non-comparable pre and post tests. The study involved 83 students who were majoring in industrial engineering at the Colombian College of Industrial Studies (ECCI) in Bogota. The finding show that use of the augmented reality model, implemented as a strategy for natural interaction with digital objects to learn functions in several variables, made it possible to obtain better results in terms of more effective and significant learning achievement among students who were enrolled in the vector calculus teaching unit, with intermediate and independent typology in the FDI dimension.

Esta pesquisa analisa a associação entre o sucesso na aprendizagem de matemática, o estilo cognitivo na dimensão dependência-independência de campo e a realidade aumentada (RA) em um ambiente virtual de aprendizagem. Para cumprir com o objetivo proposto, estruturou-se um estudo quantitativo de tipo descritivo-correlacional, com desenho de corte quase-experimental com dois grupos: um experimental e outro de controle compré-teste e pós-teste não comparáveis. Desse estudo, participaram 83 estudantes da Escuela Colombiana de Carreras Industriales (ECCI) de Bogotá, do Programa de Engenharia Industrial. Os resultados indicam que o uso do paradigma da realidade aumentada, implementada como estratégia de interação natural com objetos digitais para a aprendizagem de funções em variáveis, permitiu obter melhores resultados deforma efetiva e significativa com relação ao sucesso de aprendizagem em estudantes que cursaram a unidade didática Cálculo Vetorial, cuja tipologia na dimensão DIC é intermediária e independente.

Corn (Zea mays L.) silage (CS) is a nutritious food that can be used as a supplement in dairy cows. The aim of this study was to determine the effect of supplementation with two amounts of CS on milk production and composition, live weight and body condition, as well as on some blood indicators for energy and protein metabolism on dairy cows in early lactation and grazing low mass pasture during autumn. The study was carried out in 40 Holstein Friesian cows over 57 d. Prior to experimental treatment, milk production and days of lactation averaged 24.1 ± 2.8 kg d-1 and 62 ± 14 d, respectively. The dietary treatments consisted of two levels of supplementation with CS; 4.5 and 9 kg DM cow-1 d-1 (treatments LCS and HCS, respectively). Additionally, all the cows received a pasture allowance of 21 and 3 kg DM cow-1 d-1 of concentrate. Milk composition was determined using infrared spectrophotometry, while blood indicators were obtained using an autoanalyzer. There were not differences between treatments regarding milk production or composition, total DM or energy intake. Herbage and protein intake was higher for LCS treatment (P < 0.001). Increasing supplementation decreased (P < 0.001) daily weight gain but did not affect body condition. Plasma concentrations of βOH-butyrate were lower (P = 0.038) for the LCS treatment; while urea concentrations were higher (P = 0.003), with no differences for non-esterified fatty acids (NEFA) concentrations. Supplementation with 4.5 kg d-1 of CS was sufficient to meet the production requirements of the cows.

M.A. Gallardo, R. de la Barra, and M.E. Martínez. 2014. Pilot study for feeding preferences and grazing behavior in two breeds of sheep on a secondary succession of the Chiloé Archipelago. Cien. Inv. Agr. 41(2):249-254. A pilot study was undertaken to determine the pattern of feeding preferences and grazing behavior of the Chilota breed of sheep in the Chiloé Archipelago. First, eight Chilota and eight Suffolk Down ewes were faced with different numbers of plant species (offered only for 10 min), after fasting and after grazing a calafatal, a secondary succession dominated by shrubs. The experiment was repeated four times within a period of 22 d and included a 1-month pre-experimental period. Second, six Chilota and six Suffolk Down ewes, randomly selected from the same groups, were placed to graze on a calafatal divided into three 10-by-10 m paddocks to facilitate rotation of the animals. Observations were performed for 1 minute at 1-hour intervals for 11 hours a day, over 10 consecutive days, recording the following behaviors: grazing, browsing, resting, ruminating, and grooming. Regarding the dry matter intake of each of the three plant species present in all trials (B. chilensis, G. mucronata and D. winteri), results showed D. winteri was the most consumed and B. chilensis the least. The grazing behavior showed grazing was the main activity recorded for both breeds (especially for Suffolk Down) during the morning and evening, while resting and ruminating were the main activities recorded during the warmest hours. In summary, the breeds showed similar preferences but different grazing behavior pattern on a secondary succession of the Chiloé Archipelago.

M.A. Gallardo, R. Pulido, R. de la Barra y M.E. Martínez. 2014. Estudio piloto para preferencias y comportamiento en pastoreo en dos razas ovinas sobre una sucesión secundaria del Archipiélago de Chiloé. Cien. Inv. Agr. 41(2):249-254. Un estudio piloto fue realizado para determinar el patrón de preferencias y comportamiento en pastoreo de la raza ovina Chilota en el Archipiélago de Chiloé. Primero, ocho ovejas Chilota y ocho Suffolk Down fueron enfrentadas a diferente número de especies vegetales (no consideradas como suplemento), ofrecidas sólo por 10 min post-ayuno y post-pastoreo de un calafatal, una sucesión secundaria dominada por arbustos. El experimento fue repetido cuatro veces en un lapso de 22 d, considerando además un período pre-experimental de un mes. Posteriormente, seis Chilota y seis Suffolk (aleatoriamente seleccionadas desde los mismos grupos) fueron ubicadas para pastorear un calafatal dividido en tres potreros de 10 x 10 m para poder rotar los animales. Las observaciones fueron realizadas por 1 minuto, a intervalos de 1-hora por 11 horas diarias, durante 10 d consecutivos, registrando diferentes comportamientos, tales como: pastoreo, ramoneo, descanso, rumia, interacción y acicalamiento. Considerando la ingesta de materia seca de cada una de las tres especies presentes en todos los desafíos (B. chilensis, G. mucronata y D. winteri), los resultados mostraron que D. winteri fue la más consumida y B. chilensis, la menos consumida. El comportamiento en pastoreo mostró que el pastoreo fue la principal actividad registrada para ambas razas (especialmente en Suffolk Down) durante la mañana y la tarde, mientras descanso y rumia fueron las principales actividades durante las horas de mayor calor. En resumen, ambas razas mostraron similar patrón de preferencias, aunque diferente comportamiento en pastoreo en una sucesión secundaria de Chiloé.

Sheep production on dryland is based on natural pasture. The aim of this study was to evaluate the effect of dryland legume pastures on the fatty acid composition of lamb meat. The study included 21 Suffolk Down male lambs aged about 2-mo that were randomly assigned to three types of pastures: successional pasture, subterranean clover/Wimmera ryegrass (Trifolium subterraneum L./Lolium rigidum Gaudin), or red clover/Wimmera ryegrass (T.pratense L./L. rigidum) for 66 d, and slaughtered after. The fatty acid profile measured in the Longissimus dorsi muscle showed no significant differences as to the content of saturated (SFA), polyunsaturated fatty acids (PUFA), and the omega6/omega3 rate (co6/co3). There was a trend (p > 0.06) towards a higher monounsaturated fatty acid (MUFA) content in the meat of lambs fed on red clover when compared to the other pasture types. Although there were no significant differences among treatments, the results obtained with natural pasture cannot be extrapolated to natural dryland pastures due to their high legume content. It is concluded that using subterranean clover/Wimmera ryegrass would provide a similar meat quality when compared to results obtained from forage based on red clover/Wimmera ryegrass.

La producción ovina en el secano está basada en la pradera natural. El objetivo de este estudio fue evaluar el efecto de praderas de leguminosas de secano sobre la composición de ácidos grasos de la carne de cordero. El estudio incluyó 21 corderos machos Suffolk Down, de alrededor de 2 meses de edad, los que fueron asignados aleatoriamente en tres praderas: pradera sucesional, trébol subterráneo/ ballica Wimmera (Trifolium subterraneum L./Lolium rigidum Gaudin) o trébol rosado/ballica Wimmera (T. pratense L./L. rigidum), por 66 d, siendo posteriormente sacrificados. El perfil de ácidos grasos, medido en el musculo Longissimus dorsi no mostró diferencias significativas en contenido de ácidos grasos saturados (SFA), poliinsaturados (PUFA), y razón omega 6/omega 3 (0)6/0)3). Hubo una tendencia (p > 0,06) hacia un mayor contenido de ácidos grasos monoinsaturados (MUFA) en la carne de corderos alimentados con trébol rosado, comparado con los otros tipos de praderas. Aunque no hubo diferencias significativas entre tratamientos, los resultados obtenidos con la pradera sucesional no pueden ser extrapolados a pasturas naturales en el secano, debido a sus altos contenidos de leguminosas. Se concluye que el uso de trébol subterráneo proveería una similar calidad de carne, al comparar con forrajes basados en trébol rosado.

An experiment was carried out in order to describe the ruminal degradation characteristics of forages, in herbage mass samples (FD) and in simulated grazing samples (FS), obtained at two sward heights (high and low) from a permanent pasture (Lolium perenne L.). The degradation kinetics of the samples was studied using in situ dacron bags. Data collected were fitted according to an exponential equation. The soluble fraction (g/kg DM) of the dry matter (DM) (299 vs. 351, s.e.d.= 5.4), of the organic matter (OM) (304 vs. 376, s.e.d.= 3.3) and of the nitrogen (250 vs. 301, s.e.d.= 6.4) were significantly higher (P<0.05) for simulated samples than for the herbage mass samples. The potential degradability (g/kg DM) of DM, OM and nitrogen was significantly higher on FS compared with the FD (P<0.05). The effective degradability for the FS samples was greater than for FD samples, either for DM (474 vs. 508, s.e.d.= 13.0), OM (490 vs. 529, s.e.d.= 11.6), or nitrogen (351 vs. 419, s.e.d.= 10.0). A significant greater effect (P<0.05) of the low sward height on the effective degradability was found for the nitrogen only.

Se evaluó la dinámica degradativa de forrajes, en muestras de una pradera permanente (Lolium perenne L.), manejadas a dos alturas de pradera, alta y baja. Las muestras consistieron en forraje disponible a ras de suelo (FD) y en forraje aparentemente consumido por vacas lecheras en pastoreo continuo (FS). La degradabilidad ruminal se estudió usando la técnica de las bolsas de dacrón y los datos fueron ajustados a una ecuación exponencial. La fracción soluble (g/kg MS), de la materia seca (MS) (299 v/s 351, s.e.d.= 5,4), de la materia organica (MO) (304 v/s 376, s.e.d.= 3,3) y del nitrógeno (250 v/s 301, s.e.d.= 6,4), fueron significativamente mayores (P<0,05) en muestras de FS que en muestras de FD. La degradabilidad potencial (g/kg MS) de MS, MO y nitrógeno, fue significativamente mayor (P<0,05) en las muestras de FS, que en las muestras de FD. La degradabilidad efectiva fue mayor en las muestras de FS, que en las muestras de FD, tanto para la MS (474 v/s 508, s.e.d.= 13,0), MO (490 v/s 529, s.e.d.= 11,6) y nitrógeno (351 v/s 419, s.e.d.= 10,0). Respecto del factor altura, sólo se encontró un efecto significativo en la degradabilidad efectiva en el nitrógeno, en favor de la altura baja (365 v/s 406, s.e.d.= 10,0).