Evaluación del efecto de un probiótico en la digestibilidad de pasto estrella (Cynodon nlemfuensis) y la ganancia de peso de bovinos en condiciones tropicales
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Fecha
2003
Autores
Dueñas Loayza, Iván Adolfo
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Editor
Universidad Nacional, Costa Rica
Resumen
Los sistemas de producción de carne en el trópico requieren de cambios
importantes para asegurar la sostenibilidad de la producción. Esta situación se
logra con el fortalecimiento de los recursos naturales disponibles, a través de
prácticas adecuadas de conservación de suelos, conservación de aguas y el
mejoramiento y manejo de pastos; además del manejo de los animales que son
parte importante de los recursos de la finca. En los bovinos el buen
funcionamiento del rumen esta directamente relacionado con parámetros
productivos ya que los microorganismos que lo habitan son muy susceptibles a
cambios en la calidad de dieta, manejo, clima y enfermedades causando
ineficiencia en la digestibilidad de alimentos. Los probióticos se presentan como
una alternativa viable para mejorar la eficiencia y estabilidad de los
microorganismos y lo hacen sin efectos colaterales en la calidad de la carne y el
medio ambiente, considerándose una alternativa para el manejo más sostenible de
sistemas de producción. El objetivo de esta tesis es evaluar el efecto de una
mezcla de probióticos sobre la ganancia de peso en bovinos de carne en su fase
de engorde final bajo dos diferentes grados de intensificación del manejo y la
digestibilidad del pasto estrella en condiciones tropicales. El presente estudio se
divide en dos partes; la primera parte se realizó en la Estación Experimental
Alfredo Volio Mata de la Universidad de Costa Rica, localizada en El Alto de
Ochomogo, Cartago, Costa Rica, se trabajó con una hembra y un macho castrado
con fístula al rumen suplementados con 2 Kg de concentrado y consumieron
pasto estrella (Cynodon nlemfuensis). Se utilizó un diseño cruzado (Crossover). Para
medir la digestibilidad de los animales con y sin suplementación se utilizó la
metodología de bolsas de dacrón descrita por Orskov, también se tomó muestras
de licor ruminal a diferentes horas del día para hacer lecturas del pH. Se
encontraron efectos positivos en la degradación de materia seca, proteina cruda,
fibra detergente ácido y no así en la degradación de fibra detergente neutro. El pH en promedio aumentó de 6.63 a 6.82 y el rango de variación de pH durante el
día fue de 0.2 (tratamiento) y 0.3 (control). Para animales en las condiciones del
experimento el adicionar una mezcla de levadura, enzimas y ácidos orgánicos
tendrá un efecto positivo sobre la degradación de pasto estrella y se logra un
incremento en la degradación de la FDA y no tiene efecto significativo sobre el
consumo del pasto estrella. Para los animales del estudio el pH ruminal
incrementa a toda hora del día y se promovió un pH más estable a lo largo del
día. La segunda parte del estudio se realizó en dos fincas con animales bajo
pastoreo ubicadas en Florencia de San Carlos, Costa Rica (finca 1) con 60
hembras sin suplementación durante un periodo de 90 días y La Fortuna de San
Carlos, Costa Rica (finca 2) con 60 machos castrados suplementados con 2 kg de
concentrado por día durante un periodo de 75 días, en ambas fincas hubo un
grupo tratamiento y un testigo y se evaluó la ganancia de peso diaria (GDP)
encontrando en la finca 1 un incremento de 65.8 gr/día por efecto del probiótico
y en la finca 2 un incremento de 153.85 gr/día promedio durante el tiempo que
duró el estudio. El probiótico tuvo un efecto positivo sobre la ganancia de peso
diaria de los animales evaluados notándose en ambas fincas que la ganancia de
peso es mayor a medida que transcurrió el tiempo del ensayo. El beneficio
económico por la adición de probióticos en la dieta de animales como los de la
finca 2 fue rentable y más aún en el periodo final del engorde, pero no fue así en
la finca 1.
Meat production systems in the tropics require important changes to ensure the sustainability of production. This situation is achieved by strengthening the available natural resources, through adequate soil conservation practices, water conservation and pasture improvement and management; in addition to the management of the animals, which are an important part of the farm's resources. In cattle, the good functioning of the rumen is directly related to productive parameters, since the microorganisms that inhabit it are very susceptible to changes in diet quality, management, climate and diseases, causing inefficiency in feed digestibility. Probiotics are presented as a viable alternative to improve the efficiency and stability of the microorganisms and do so without collateral effects on the quality of the meat and the environment, being considered an alternative for a more sustainable management of production systems. The objective of this thesis is to evaluate the effect of a probiotic mixture on weight gain in beef cattle in their final fattening phase under two different degrees of management intensification and star grass digestibility under tropical conditions. The present study is divided into two parts; the first part was carried out at the Alfredo Volio Mata Experimental Station of the University of Costa Rica, located in El Alto de Ochomogo, Cartago, Costa Rica, with a female and a castrated male with rumen fistula supplemented with 2 kg of concentrate and consuming star grass (Cynodon nlemfuensis). A crossover design was used. To measure the digestibility of the animals with and without supplementation, the dacron bag methodology described by Orskov was used, and samples of rumen liquor were taken at different times of the day for pH readings. Positive effects were found in the degradation of dry matter, crude protein and acid detergent fiber, but not in the degradation of neutral detergent fiber. The average pH increased from 6.63 to 6.82 and the range of pH variation during the day was 0.2 (treatment) and 0.3 (control). For animals under the conditions of the experiment, the addition of a mixture of yeast, enzymes and organic acids will have a positive effect on the degradation of star grass and an increase in FDA degradation is achieved and has no significant effect on star grass consumption. For the animals in the study, ruminal pH increases at all times of the day and a more stable pH was promoted throughout the day. The second part of the study was carried out in two farms with grazing animals located in Florencia de San Carlos, Costa Rica (farm 1) with 60 females without supplementation during a period of 90 days and La Fortuna de San Carlos, Costa Rica (farm 2) with 60 castrated males supplemented with 2 kg of concentrate per day during a period of 75 days, in both farms there was a treatment group and a control and the daily weight gain (GDP) was evaluated, finding in farm 1 an increase of 65. The probiotic had a positive effect on the daily weight gain (DWG) of 65.8 g/day in farm 1 and an average increase of 153.85 g/day in farm 2 during the study period. The probiotic had a positive effect on the daily weight gain of the animals evaluated, noting in both farms that the weight gain increased as the time of the trial elapsed. The economic benefit from the addition of probiotics in the diet of animals such as those in farm 2 was profitable and even more so in the final fattening period, but this was not the case in farm 1.
Meat production systems in the tropics require important changes to ensure the sustainability of production. This situation is achieved by strengthening the available natural resources, through adequate soil conservation practices, water conservation and pasture improvement and management; in addition to the management of the animals, which are an important part of the farm's resources. In cattle, the good functioning of the rumen is directly related to productive parameters, since the microorganisms that inhabit it are very susceptible to changes in diet quality, management, climate and diseases, causing inefficiency in feed digestibility. Probiotics are presented as a viable alternative to improve the efficiency and stability of the microorganisms and do so without collateral effects on the quality of the meat and the environment, being considered an alternative for a more sustainable management of production systems. The objective of this thesis is to evaluate the effect of a probiotic mixture on weight gain in beef cattle in their final fattening phase under two different degrees of management intensification and star grass digestibility under tropical conditions. The present study is divided into two parts; the first part was carried out at the Alfredo Volio Mata Experimental Station of the University of Costa Rica, located in El Alto de Ochomogo, Cartago, Costa Rica, with a female and a castrated male with rumen fistula supplemented with 2 kg of concentrate and consuming star grass (Cynodon nlemfuensis). A crossover design was used. To measure the digestibility of the animals with and without supplementation, the dacron bag methodology described by Orskov was used, and samples of rumen liquor were taken at different times of the day for pH readings. Positive effects were found in the degradation of dry matter, crude protein and acid detergent fiber, but not in the degradation of neutral detergent fiber. The average pH increased from 6.63 to 6.82 and the range of pH variation during the day was 0.2 (treatment) and 0.3 (control). For animals under the conditions of the experiment, the addition of a mixture of yeast, enzymes and organic acids will have a positive effect on the degradation of star grass and an increase in FDA degradation is achieved and has no significant effect on star grass consumption. For the animals in the study, ruminal pH increases at all times of the day and a more stable pH was promoted throughout the day. The second part of the study was carried out in two farms with grazing animals located in Florencia de San Carlos, Costa Rica (farm 1) with 60 females without supplementation during a period of 90 days and La Fortuna de San Carlos, Costa Rica (farm 2) with 60 castrated males supplemented with 2 kg of concentrate per day during a period of 75 days, in both farms there was a treatment group and a control and the daily weight gain (GDP) was evaluated, finding in farm 1 an increase of 65. The probiotic had a positive effect on the daily weight gain (DWG) of 65.8 g/day in farm 1 and an average increase of 153.85 g/day in farm 2 during the study period. The probiotic had a positive effect on the daily weight gain of the animals evaluated, noting in both farms that the weight gain increased as the time of the trial elapsed. The economic benefit from the addition of probiotics in the diet of animals such as those in farm 2 was profitable and even more so in the final fattening period, but this was not the case in farm 1.
Descripción
Maestría en Producción Animal Sostenible
Palabras clave
PASTO ESTRELLA, CYNODON NLEMFUENSIS, GANADO DE CARNE, BOVINOS, BOVINE CATTLE, PROBIÓTICOS, PROBIOTICS