J. R. Stuart- PhD
- Developer at Instituto de Ciencia Animal
J. R. Stuart
- PhD
- Developer at Instituto de Ciencia Animal
About
45
Publications
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124
Citations
Introduction
Ruminant nutrition and management, physiology of digestión of ruminants, mathematical modelling, agro industrial byproducts for ruminant feeding, pasture management
Current institution
Additional affiliations
January 1980 - August 2017
August 1980 - October 2015
August 1980 - October 2015
Publications
Publications (45)
Se diseñó un algoritmo para estimar el consumo voluntario de un forraje basado en su composición morfológica (hojas y tallos en diferentes proporciones y edades) y el valor lastre de cada una de ellas, cuando se ofrecen cantidades crecientes al animal. Para la evaluación se supuso un forraje compuesto por seis fracciones, cuyas proporciones y valor...
Se diseñó un algoritmo para estimar el consumo voluntario de un forraje basado en su composición morfológica (hojas y tallos en diferentes proporciones y edades) y el valor lastre de cada una de ellas, cuando se ofrecen cantidades crecientes al animal. Para la evaluación se supuso un forraje compuesto por seis fracciones, cuyas proporciones y valor...
Se realizó un estudio de simulación a partir de los datos tomados de la literatura para estudiar el efecto de la carga la ganancia de peso vivo necesarias durante la temporada lluviosa para obtener la máxima producción por hectárea (ha) a diferentes niveles de fertilización, la cual se denominó como “Carga Óptima”, en pastizales de bermuda cruzada...
Se realizó un estudio de simulación a partir de los datos tomados de la literatura para estudiar el efecto de la carga la ganancia de peso vivo necesarias durante la temporada lluviosa para obtener la máxima producción por hectárea (ha) a diferentes niveles de fertilización, la cual se denominó como “Carga Óptima”, en pastizales de bermuda cruzada...
Un procedimiento simple para estimar la producción de metano y dióxido de carbono del ganado vacuno en pastoreo. Autor: J. R. Stuart. Instituto de Ciencia Animal, Apartado Postal 24, San José de las Lajas, Mayabeque. Correo. jstuart@ica.co.cu Resumen Como una forma de contribuir al conocimiento del aporte que hacen los animales de un predio a la pr...
Mediante la introducción de un parámetro convenientemente seleccionado, se introducen adecuaciones en la representación de la serie binómica, con lo cual se pueden a representar funciones de potencias mediante ecuaciones cuadráticas. Los parámetros de las ecuaciones obtenidas mediante la aplicación del procedimiento descrito son numéricamente simil...
Se realizó un ejercicio de cálculo a partir de datos bibliográficos para caracterizar el balance del carbono según los productos finales de la fermentación de Neocallimastix frontalis, un hongo anaerobio habitante del aparato digestivo de los rumiantes, como paso previo a la estimación de los requerimientos energéticos para la síntesis y los gastos...
The chemical characteristics, before and after filtering, of the waste products from the African palm (Elaeis guineensis) oil and of the sheep tallow diluted at 50, 92 and 121º C were determined. Residual water from the filtrate and the profile of fatty acids were analyzed as possible sources of protected fats from ruminal degradation. A completely...
The chemical characteristics, before and after filtering, of the waste products from the African palm (Elaeis guineensis) oil and of the sheep tallow diluted at 50, 92 and 121 C were determined. Residual water from the filtrate and the profile of fatty acids were analyzed as possible sources of protected fats from ruminal degradation. A completely...
This study was carried out in order to evaluate the chemical composition and in situ ruminal degradability of dry matter in mixed pre-dried silages with the inclusion of Pennisetum purpure¬um cv Cuba CT-169 and tree forage of Moringa oleífera cv Supergenius. For the development of this study, micro-silos built from PVC pipes were used. The treatmen...
In order to evaluate the in situ degradability of PREDICAL (bagasse pith of sugar cane treated with calcium hydroxide and steam) as feed for ruminants, and compare it with the degradability of untreated bagasse pith of sugar cane, star grass (43 d of regrowth), sugar cane and Pennisetum purpureum cv. Cuba CT-115, two experiments of in situ digestib...
The objective of this experiment was to finish British steers with 18 years of age and 380 kg of LW, with the lowest possible production cost. The impact of high-tannin sorghum grain on meat production was also evaluated. The research was conducted at the experimental field Cesareo Naredo of the INTA Bordenave, in Buenos Aires, Argentina, during tw...
The objective of this experiment was to finish British steers with 18 years of age and 380 kg of LW, with the lowest possible production cost. The impact of high-tannin sorghum grain on meat production was also evaluated. The research was conducted at the experimental field Cesareo Naredo of the INTA Bordenave, in Buenos Aires, Argentina, during tw...
Abstract
This work was designed to evaluate different diets in conditions of drought or flooding. The main objective was to study the economic and productive performance of 12 growing Angus heifers confined in a feedlot. Three treatments were established with two replications under a completely random design and in two phases The first one during t...
La deposición de proteína corporal en el rumiante es un proceso complejo, regulado por diferentes factores, entre los que se encuentran el sexo, la edad, el potencial genético y la alimentación. Se ha propuesto un modelo dinámico para el crecimiento y la composición corporal del rumiante (Oltjen et al1986, 2000), el cual estima la deposición de pro...
Resumen
La modelación matemática es una herramienta de gran valor para establecer el racionamiento de los animales, al facilitar el manejo de los distintos procesos biológicos como un sistema, y al mismo tiempo, al tiempo que facilita la integración de nuevos conocimientos (Tedeschi y Col. 2005). Con el objetivo de llegar a conclusiones al respecto...
Forage sorghums (Sorghum sp.), Sudan type, are quite used in Argentina as fresh forage due to their large production (8 to 15.000 kg DM ha -1), permitting to support high stocking rate (three to six animals ha -1) during the summer. Nevertheless, due to nutritional unbalances, daily weight gains (DWG) are low (400 to 600 g daily). The utilization o...
Sixty crossbred heifers (371 ± 7 kg) were used in a 63-d feeding trial (4 pens per treatment in a randomized complete block design) to evaluate the influence of dietary supplementation with zilpaterol hydrochloride (ß-agonist) or with different levels of chromium-enriched live yeast (Cr-YC) on growth performance and carcass characteristics. Heifers...
The finishing stage of fattened steers (>450 kg animal-1) is usually conducted in feedlots, due to their high energy demands. However, because of the high production costs (PC), middle and small farms are limited in utilization. The adequate energy-protein balance of forage cereals, rich in soluble nonstructural carbohydrates (SNSC), and low in sol...
Twenty-eight Pelibuey lambs with initial liveweight of 14.9 ± 2.2 kg were used through completely randomized design with factorial fit to assess the productive performance of the animals fed high energy rations and different levels of dehydrated citrus pulp (DCP) and urea. Also, the concentration of ureic nitrogen (UN), glucose and phosphorus (P) i...
Ruminants produce methane in rumen out of the end products from the fermentation of carbohydrates in feeds through the activity of a community of microbes of the Archaea bacteria dominion. This process reduces the efficiency in the use of feed energy. In order to study the effect of inclusion of starchy sources on the population of methanogenic bac...
Twenty-four weaned calves (12 females and 12 males) with general average weight of 116 kg were used in a random block design with factorial fit to study the effect of sex and of supplementation with a probiotic (Sorbial) on the liveweight gain. The animals were given an integral ration with 40 % ground grass hay. The experiment lasted 111 d. The ge...
One hundred and twenty-four reports from a sheep rearing unit were used to analyze the feeding balance and some reproductive indicators of Pelibuey sheep. The basic pasture was Paspalum notatum without irrigation or fertilization. The animals were supplemented with sugarcane, without protein during the rainy season, and with a commercial concentrat...
Seven random samples were collected from 10 lots of filter cake mud, bagasse pith, and predigested bagasse pith of the Agroindustrial Sugarcane Mill λHector Molinaλ, located in Havana province. Part of the predigested bagasse pith was submerged in tap water for 1 h. The samples of each of the byproducts were arranged for the determination of the in...
RESUMEN Se presenta un sistema actualizado para los requerimientos nutricionales del vacuno, correspondiente al crecimiento y la composición corporal, fundamentado en la curva de Gompertz para la descripción del crecimiento, y en un modelo cuadrático para la estimación del contenido de grasa. Se demostró que el mo-delo cuadrático es equivalente a l...
El helecho macho (Pteridium aquilinum) es una planta tóxica caracterizada por producir en el bovino
dos tipos de enfermedades, debidamente identificadas y para las cuales no existe hasta el momento ningún
tipo de tratamiento (Smith et al., 1998). Estas son la hematuria enzoótica bovina y el carcinoma de las
porciones superiores del tracto digestivo...
This book contains 86 chapters based on papers presented at the 6th International Symposium on Poisonous Plants (ISOPP6), August 2001, Glasgow, UK. A range of topics are covered, from poisonous plant biochemistry to toxic effects in animals (particularly grazing farm animals) and humans. The contents include the evolution of antinutrients and toxin...
The variations in in situ ruminai dry matter (DM) and total nitrogen (TN) degradability were studied in six ecotypes of Leucaena leucocephala (CIAT-7929, 9379, 9101, 7872, 7988 and Peru), which are promising for ruminant feeding. High coefficients of variations (CV) were found in the parameters of DM degradability, with higher values in the degrada...
Eighteen male bovines (3/4 Holstein x Zebu) of liveweight between 144 and 254 kg were selected to study the protein-energetic supplementation in their performance, according to a completely randomized design and during the rainy period. The animals grazed on natural pasture (mixture of Dichantium annulatum and Papalum notatum), associated with a mi...
Eighteen Holstein calves with an initial live weight of 175 kg were used in a random block design with three treatments to study the effect of including soapstock alone or with calcium as feed ingredient on the productive performance of these animals. Rations consisted of ad libitum grass forage and 2.5 kg supplement of wheat bran, molasses, soybea...
We studied the toxicity caused by chronic ingestion of Pteridium aquilinum (bracken) in cattle in the humid Chaco of Tarija, Bolivia. Bovine enzootic haematuria (BEH) and Carcinoma of the esophagus (CE) affected the herds. Sick animals showed caquexia, anemia, leucopenia and urine that turned from pink to intense red color with the presence of bloo...
Six rams of approximately 34 kg LW were used in a 3 x 3 double Latin square balance design to study the effect of the addition of soapstock with or without calcium on N balance and digestibility. The animals were fed 700 g of star grass (Cynodon nlemfuensis) hay and 500 g of a wheat bran supplement, molasses and other components. 17% of hay meal (c...
A total of 300 crossbred Holstein heifers of an average liveweight of 196 kg were housed in rustic facilities under drylot conditions, according to a random block design with two treatments and three replications each. Treatments consisted of ad libitum supply of cleaning centre residues (sugar cane straw) treated with ammonia and 2 kg of a supplem...
Se llevaron a cabo tres pruebas de digestibilidad in vitro de la materia seca con el objetivo de estudiar el efecto del tratamiento con NaOH al 6% en la digestibilidad de las hojas verdes y secas de la caña de azúcar así como el bagacillo y las pajas de cebada, trigo y avena. Se evaluó además el efecto del sodio excesivo en la digestibilidad de la...
Se realizó una prueba de comportamiento con 32 corderos distribuidos por parejas que recibían raciones a base de paja de caña tratatada con NH3 al 3%. Se utilizó un diseño completamente aleatorizado. Los tratamientos fueron raciones que contenían 30. 45, 60 y 75% de paja molida (PM) y tratada con NH3 y el resto de la ración eran alimentos de alto v...
