Efecto de la suplementación con proteína sobre algunos parámetros ruminales en bovinos

The objective of this study was to measure the effect of soya bean supplementation on some ruminal parameters. A diet composed of rye grass hay was given to Holstein-Freisian dry cows fitted with permanent rumen fistulae, with (CS) or without (SS) supplementation of 1 Kg soya bean meal per cow day. Samples of rumen content were withdrawn at 0, 2,4, 6,8; and 10 hours after supplementation, simultaneously for both treatments. The samples were processed for: ammonia, ATP and volatile fatty acids (AGV) concentration, AGV composition and rumen bacterial counts. Significant differences between treatments were found for ammonia concentration (CS: 86.4 mg/l; ss. 53.7 mg/I; P<0.01), number of bacteria (CS: 1.11 x 109; SS: 0.68x 109; P<0.01) and propionic acid concentration (CS: 16.8 mmol/I; SS: 15.4 mmol/I; P<0.01) and also between sampling times for ATI' concentration, in both treatments, when zero hour (sample taken immediately before supplementation) was compared with 2, 4 and 6 hours (P<0.01): zero hour: 9.7 g ATP/g; two hours: 20.6 g/g; four hours: 19.7 g/g; six hours: 25.7 g/g. The number of rumen microbes was 62% higher in CS when compared to SS, indicating the effect of soya bean meal upon rumen population growth.Con el objeto de medie el efecto de la suplementación con harina de soja sobre parámetros ruminales, se suministró una dieta de heno de rye grass a vacas secas Holstein-Freisian fistuladas de rumen, con (CS) o sin (SS) suplementación de 1 Kg de harina de soja por vaca/día. Se obtuvieron muestras de contenido ruminal a las 0,2,4,8, y 10 horas de consumido el suplemento, simultáneamente para ambos tratamientos y sobre ellas se midió: concentración de amoníaco, ATP y ácidos grasos volátiles (AGV), composición de AGV y conteo de bacterias ruminales. Se encontraron diferencias significativas en el nivel de amoniaco (es: 86.4 mg/I; ss: 53.7 mg/I; P<0.01), número de bacterias (CS: 1.11 x 109; SS: 0.68 x 109; P<0.01), concentración de ácido propiónico (CS: 16.8 mmol/I; SS: 15.4 mmol/l; P<0.01) y ATP entre la hora cero (muestra tomada previamente al suministro del suplemento) y Ias horas 2, 4 Y 6 de muestreo, para ambos tratamientos (P<0.01): Hora cero: 9.7 g ATP/g; hora dos: 20.6 g/g; hora cuatro: 19.7 g/g; hora seis: 25.7 g/g. El número de microorganismos ruminales fue un 62% mayor en el tratamiento con suplementación respecto del testigo, indicando el efecto de la harina de soja sobre el crecimiento de la población ruminal

Estimation of Organic Matter Digestibility and Intake from Faecal Organic Matter and Daily N Excretion and Concentration

This study was performed with grazing sheep, to establish: a) if the amount of total faecal N (C; in g 100g-1 of organic matter intake (OMI)) remains constant at three feeding levels, in four utilisation periods of deferred Panicum coloratum cv. Verde; b) the relationship between C and faecal N fractions, and c) the relationship between faecal daily excretion of OM and N, and OMI. Intake increased (P\u3c 0.01) with utilisation period, and was related (r = - 0.82; P\u3c 0.01) to the protein content of food, the insoluble N fraction (r = -0.49; P\u3c 0.01) and the soluble:insoluble N ratio (r = 0.41; P\u3c 0.01) in faeces. No relation with total N concentration (r = -0.22; P\u3e 0.05) or soluble N fraction (r = -0.02; P\u3e 0.05) in faeces could be found. Daily excretion of OM and N were positively related (R2 = 0.93 and 0.96, respectively; P\u3c 0.01) to OMI. The slopes of regression lines, but not the intercepts, were different (P\u3c 0.01) between evaluation periods. The digestibility can be estimated from OMI and faecal N whenever time of the year is taken into consideration

Efecto del tratamiento húmedo con NaOH sobre la desaparición de materia seca y carbohidratos de paja de cebada incubada in sacco

The effect of wet NaOH treatment on dry matter and carbohydrates disappearance of barley straw from nylon bags incubated in saco. Treated (CT) and untreated (CS) barley straw sample were incubated in the rumen of one cow for 2, 6, 12, 24, 48 and 72 hours. Disappearance of dry matter, organic matter, individual sugars, cellulose and hemicellulose was measured. The cow was fed a barley straw (untreated) diet supplemented with fishmeal, rolled barley and a mineral-vitamine mixture. The chemical treatment of the straw was a modification of the Beckmann method; the chemical reactant was sodium hydroxide and the process consisted in a solubilization in diluted NaOH solution. The method used was systematized in. way that the water used for washing out the solubilized matter was reused for the solubilization itself. The treatment was highly effective in improving the degradation of straw in the rumen. AII the degradation curves showed higher value for untreated straw than for treated straw al 2 h of incubation; these differences were presumably due lo loses of water soluble substances and fine particles from the untreated straw and not lo true digestion. From 6 h onwards the treatment with alkali produced a higher digestion in dry matter, organic matter and all sugar and polysaccharides, except cellulose, which digestion was only higher intreated straw from 24 h onwards. Degradability were: dry matter: CT: 62.7; CS: 40.7; organic matter: CT: 60.8; CS: 39.9; arabinose: CT: 68.1; CS: 52.9; mannose: CT: 63.4; CS: 44.6; galactose: CT: 69.8; CS: 54.4; xylose: CT: 70.1; CS: 46.6; hemycellulose: CT: 69.8; CS:47.1; cellulose: CT: 660.8: CS: 45.3. All differences between treatment were significant at 1% level.Muestras de paja de cebada tratada (CT) y sin tratar (es) fueron incubadas en el rumen de una VKa lechera fistulada de rumen, por 2, 6, 12, 24, 48 y 72 horas. Se midió la desaparición de materia seca, materia orgánica, xilosa, arabinosa, galactosa, manosa, celulosa y hemicelulosa, y ponderando por una tasa de pasaje estimada (2% h), se calculó la degradabilidad de cada fracción. La vaca fue alimentada con una dieta compuesta por paja de cebada (sin tratar), harina de pescado, grano de cebada aplastado, minerales y vitaminas. El tratamiento químico de la paja consistió en una modificación del método Beekman de solubilización en una solución de hidróxido de sodio al 1.5%. El método utilizado fue sistematizado de manera tal que el agua usada para el lavado del material solubilizado fue reutilizada para la siguiente soIubilización. El tratamiento fue altamente efectivo para el mejoramiento de la degradación de la paja en el rumen. Todas las curvas de degradación mostraron valores más altos para la paja no tratada a las dos horas de incubaci6n; estas diferencias fueron presumiblemente debido a las pérdidas de sustancias solubles en agua y partículas finas en la paja no tratada y no a digestión verdadera. A partir de las 6 horas de incubación, el tratamiento con álcali produjo mayor desaparición de materia seca, materia orgánica y todos los azúcares y polisacáridos, excepto celulosa, cuya digestión fue 11610 mayor a partir de las 24 horas. Las degradabilidades obtenidas fueron Ias siguientes.: materia seca: CT: 62.7; es: 40.1; materia orgánica: CT: 60.8; es: 39.9; arabinosa: CT: 68.1; es: 52.9; manosa: CT: 63.4; es: 44.6; galactosa: CT: 69.8; es: 54.4; xilosa: CT: 70.1; es: 46.6; hemicelulosa: CT: 69.8; es: 41.1; celulosa: CT: 60.8; es: 45.3. Todas las diferencias entre tratamientos fueron significativas al nivel del 1%

Factors affecting degradation of barley straw in sacco and microbial activity in the rumen of cows fed fibre-rich diets. JI: The level of supplemental fishmeal

A diet composed of 76.2% untreated barley straw + 23.8% rye grass hay was given to three nonlactating cows at 90% of ad libitum intake. The cows were supplemented via cannulae with three differents levels of fishmeal in arder to make the ration up to 8%, 10% and 14% crude protein on a dry-matter basis. Treatments were arranged in a Latin Square design. Nylon bags containing untreated barley straw were incubated in the rumen 01 the cows for up to 72 h. Degradability of dry matter, total organic matter and the individual components of the cell wall of barley straw were affected by the protein level of the dlel. The Inclusion of fishmeal to a Ievel of 14% dietary protein produced the highest degradability of all parameters measured. The protein level also affected ammonia and total VFA concentrations; both fermentation products were highest in the treatment with the high fishmeal level. Rumen pH and rumen outflow rate of Iiquid and particulate phases were not affected by protein level. The ATP concentration found in the solid residue, remaining after removal of the liquid phase from the rumen content, Increases with increasing fishmeal level., while ATP in the Iiquid phase remained unchanged. This indicates that, under the conditions of this study, fishmeal exerts its effects on the microbes intimately associated lo the fibre, and not upon the whole microbial population. The microbial DNA concentration of digesta nylon bags increased during the first 24 h of incubation and then decreased until the end of incubation, indicating a process of colonization and depletion of degradable substrates.Resúmenes de Trabajos presentados en otras publicaciones (por docentes de la UNLPam.), Publicado en Animal Feed Science Technology, 70: 11-22, 1998

Intake Estimation of Rams under Grazing Condition in a Deferred Pastures of \u3ci\u3ePanicum coloratum\u3c/i\u3e by Two Techniques

The goal of this study was to quantify the organic matter intake (OMI) of Pampinta rams grazing in a Panicum coloratum cv Verde differed pasture. The OMI was compared by two methods: a) the difference between the forage measured in pre and post-grazing condition, and b) the faecal production:digestibility ratio of the diet, estimated by total faecal gathering, and from the quantity of total faecal N in g per 100 g-1 of OMI and the concentration of total faecal N, respectively. The OMI estimated by difference between the forage measured in pre and post-grazing was 9 % higher (P\u3c 0,05) than the one estimated from total faecal gathering and OMD. Interaction was not detected (P\u3e 0,10) between treatments (length of the deferment period) and estimation method. The use of the faecal N can be utilized, considering the time of the year, to estimate the OMD and OMI in grazing condition in P. coloratum deferred pastures

Slowly and non-digestible tissues in Elytrigia scabrifolia y E. Scabriglumis

The estimation of the percentages of slowly and non-digestible tissues allows the prediction 01the nutritive value of forages. In this study, the percentages of tissues in sheaths and blades of two species natives of the Salado Basin and abundant in the Pampas range pastures (Elytrigia scabrifolia y E. scabriglumis) were determined as a primary evaluation of their forage qualily. The estimations were done in the vegetative and reproductive stages. A split-plots design in space and time, with species as main plot, plant part (sheath or blade) as secondary plots, and three replications was used. Percentages of all leaf tissues were estimated by microscopic analysis of cross section and were grouped in rapidly and slowly plus non-digestible tissues. The variation of all leaf tissues between species, plant parts and growth stage, and the percentages variation of slowly and non-digestible tissues were analysed by principal components and by ANOVA, respectively. In all cases, the percentages of sclerenchyma were lower than 10% and those of slowly plus non-digestible tissues were lower than 45%. The percentages of slowly and non-digestible tissues did not differ (P<0.05) either between species (P<0.05) or plant parts, but increased 34% with the advancement of growth from the vegetativa to the reproductive stage. Although the percentage of slowly and nondigestible tissues suggest that both species have an acceptable nutritive value, this rating could be altered by the degree of forage lignification.Resúmenes de Trabajos presentados en otras publicaciones (por docentes de la UNLPam.) Publicado en Archivos latinoamericanos de producción animal, 5(Supl. 1): 118-121, 1997

Slowly and non-digestible tissues in Elytrigia scabrifolia y E. Scabriglumis

The estimation of the percentages of slowly and non-digestible tissues allows the prediction 01the nutritive value of forages. In this study, the percentages of tissues in sheaths and blades of two species natives of the Salado Basin and abundant in the Pampas range pastures (Elytrigia scabrifolia y E. scabriglumis) were determined as a primary evaluation of their forage qualily. The estimations were done in the vegetative and reproductive stages. A split-plots design in space and time, with species as main plot, plant part (sheath or blade) as secondary plots, and three replications was used. Percentages of all leaf tissues were estimated by microscopic analysis of cross section and were grouped in rapidly and slowly plus non-digestible tissues. The variation of all leaf tissues between species, plant parts and growth stage, and the percentages variation of slowly and non-digestible tissues were analysed by principal components and by ANOVA, respectively. In all cases, the percentages of sclerenchyma were lower than 10% and those of slowly plus non-digestible tissues were lower than 45%. The percentages of slowly and non-digestible tissues did not differ (P<0.05) either between species (P<0.05) or plant parts, but increased 34% with the advancement of growth from the vegetativa to the reproductive stage. Although the percentage of slowly and nondigestible tissues suggest that both species have an acceptable nutritive value, this rating could be altered by the degree of forage lignification.Resúmenes de Trabajos presentados en otras publicaciones (por docentes de la UNLPam.) Publicado en Archivos latinoamericanos de producción animal, 5(Supl. 1): 118-121, 1997

Estimation of intake and digestibility of kleingrass from in situ parameters measured in sheep

The voluntary intake and digestibility of kleingrass (Panicum coloratum cv. Verde) were measured in seven periods, comprising one full year. The forage was offered twice a day ad Iibitum to .seven rams, frtted with faces collection bags; each experimental period was composed of 8 days for adaptation and 8 days for collection of data. The dry matter (DM) Intake (DMI) varied from 36.1 to 64.9 glkg MO.75, the digestible dry-matter Intake (DDMI), from 17.4 to 41.9 glkg MO.75 and the in vivo dry matter apparent digestibility (DMD), from 0.471 to 0.667. Daily samples of offered forage were taken and pooled subsamples from each of the seven periods were incubated in nylon bags in the rumen of three Hereford steers. The data were fitted to the exponential equation: p= a + b (1-e~) to estimate p (the proportionate loss of DM at time t of incubation); effective degradability (ED) and lag time (L) were also estimated. The parameters obtained in situ were related to the in vivo results by simple and multiple regression. The correlation coefficients of the rate of degradation {9 and ED with DMI, DDMI and DMD were, respectively, 0.96 and 0.97; 0.97 and 0.96; 0.86 and 0.88. By including, Q, Q and k into a multiple regression analysis, the coefficients of determination (R2) were: DMI: 0.99; DDMI: 0.99 and DMD: 0.91. Within the conditions of this study, the parameters obtained in situ were reasonable estimators of voluntary intake and digestibility.Resúmenes de Trabajos presentados en otras publicaciones (por docentes de la UNLPam.) Publicado en Animal Science, 67: 535-540, 1998

Comportamiento de verdeos invernales en Santa Rosa, La Pampa. II. Estimación de la degradabilidad ruminal in sacco

The objetive of this study was to evaluate dry matter (DM) rumen degradation kinetics of cultivars (cvs) of small grain pastures. Cultivars were: avena (Avena sativa L.) cv Don Victor, avena (Avena byzantina C. Koch) cv Millauquén, cebada (Hordeum vulgare L.) cv Ullaiché, centeno (Secale cereale L.) cvs Choiqué y Naicó, tricepiro (Triticum x Secale x Thinopyron) unea 3/40 y triticale (x Triticosecale Witt.) cvs Don Norman y Tehuelche. Each plot was cuftour times, on the followingdates: June r-, August 12th, September 30th and November 30th The harvested forage, dried and milled, was incubated in the rumens into suspended nylon bags. Three Holstein-Freisian steers, titted with permanent rumen canulae were used in the experiment. Animals were fed on ad libitum alfalfa hay and water. Ruminal degradability was estimated using DM rate of disappearance, through an exponential model p = a + b(1- exp(-ct)). Data were compared by ANOVA, under a split-plot design Treatment mean were separated using Tukey's test (α= 0.05). Most differences between cultivars in effective degradability were given by differences in the soluble:insoluble potentially degradable fractions ratio, and due to different fractional rates of degradation. Non-degradable fraction was similar (p>0.05) between cultivars.El objetivo de este estudio fue evaluar la cinética de la degradación ruminal de la materia seca (MS) en cultivares (cvs) de verdeos invernales. Estos fueron: avena (Avena sativa L.) cv Don Víctor, avena (Avena byzantina C. Koch) cv Millauquén, Cebada (Hordeum vulgare L.) cv Ullaiché, centeno (Secale cereale L.) cvs Choiqué y Naicó, tricepiro (Triticum x Secale x Thinopyrum) Unea3/40 y tritícale (x Triticosecale Witt.) cvs Don Norman y Tehuelche. Se realizaron cuatro cortes, sobre una misma parcela en las fechas 07-06, 12-08, 30-09 Y 30-11. El forraje secado y molido, fue incubado en bolsitas de nylon suspendidas en rumen. Se utilizaron 3 novillos Holando-argentino con fístula ruminal, alimentados con heno de alfalfa y agua a voluntad. La tasa de desaparición de la MS fue el criterio utilizado para calcular la degradabilidad, a través de un modelo exponencial p = a + b(1-exp-Ct).Los datos fueron analizados mediante ANOVA, utilizando un diseño de parcelas divididas, y Test de Tukey  (α=0,05).En general, las diferencias en degradabilidad efectiva entre cvs se correspondieron a diferencias en la relación entre la fracción soluble y la fracción insoluble potencialmente degradable, y a diferencias en la tasa fraccional de degradación. La fracción indegradable resultó similar (p>0,05) entre cultivares

Comparación de modelos utilizados para estimar la materia seca in sacco y la degradabilidad

El objetivo del presente estudio fue comparar algunos de los modelos disponibles, utilizados para estimar la dinámica de la desaparici6n y la degradabilidad de la materia seca (MS) en rumen, en dos grupos de gramíneas: Verdeos invernales (VI) y perennes de crecimiento estival (GrE). Las muestras (n = 327) fueron incubadas en bolsas de nylon en el rumen de tres novillos Holando-Argentino, con fistula ruminal. Los datos experimentales obtenidos, fueron tratados matemáticamente utilizando distintos modelos para estimar tasa de degradación y degradaci6n efectiva de la MS. La tasa de desaparici6n fue estimada a partir de dos modelos no lineales similares, con y sin tiempo de retardo y con una ecuación de primer orden. Las degradabílidades efectivas se calcularon utilizando las constantes estimadas por los dos modelos no lineales con y sin tiempo de retardo, por sumatoria de las degradaciones entre perlados sucesivos y por estimación de la relación entre la tasa de pasaje de la MS no degradada para las primeras horas de incubación y la de la MS insoluble. La degradabilidad máxima se estimó a través de la predicción de la asíntota de la hipérbola, determinando la intercepción de la doble reciproca de tiempo y materia seca no degradada. Los parámetros equivalentes entre modelos fueron comparados como observaciones apareadas dentro de cada recurso forrajero. La asociación entre parámetros y entre valores de degradabilidad se evaluó por análisis de correlación. Las diferencias entre parámetros comparables en VI y GrE fueron significativas (P < 0,01), la asociación fluctuó entre 0,72 y 0,96. Las correlaciones entre degradabilidades efectivas y máxima obtenidas mediante los distintos modelos fueron estrechas (r > 0,97). Todos los modelos estimaron con similar precisión la degradabilidad efectiva de la MS del alimento, independientemente del valor nutritivo del mismo. Por lo tanto, cualquiera de los modelos estudiados puede utilizarse para estimar la degradabilidad de la MS. Sin embargo, a partir de un trabajo experimental similar, puede obtenerse mayor información si ésta se procesa utilizando el modelo no lineal con tiempo de retardo.Resúmenes de Trabajos presentados en otras publicaciones (por docentes de la UNLPam.), Publicado en Revista argentina de producción animal, 17(4): 353- 364, 199