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Limitaciones físicas y químicas de la digestibilidad de pastos tropicales y estrategias para aumentarla

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El alto contenido de fibra en forrajes tropicales y su reducida digestibilidad por los rumiantes, es uno de los más grandes limitantes para la productividad animal en el trópico. En este artículo la discusión se centra en dos grandes áreas. La primera tiene que ver con el consumo voluntario de rumiantes en pastoreo, factores que lo afectan y estrategias exitosas para incrementarlo. Debe reconocerse que, aunque de fácil determinación en animales estabulados, la estimación de este parámetro bajo condi­ciones de pastoreo ha sido tradicionalmente difícil e imprecisa. Estrategias como la renovación de praderas, el establecimiento de asociaciones gramínea – leguminosa y la suplementación estratégica, han sido utilizadas exitosamente para aumentar el consumo voluntario de rumiantes en pastoreo. La segunda área de discusión describe los factores que afectan la digestibilidad de la fibra en rumiantes y plantea estrategias para aumentar la degradabilidad de la fibra en el rúmen. Ambas áreas están muy relacionadas entre sí, pues del adecuado entendimiento y optimización de ambos procesos, depende gran parte de la sostenibilidad económica y ambiental de la gana­dería del trópico.
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REVISTA CORPOICA • VOL 6 N°1 • ENERO-JUNIO 2005
ARTÍCULO DE REVISIÓN
Rolando Barahona Rosales1 y
Solange Sánchez Pinzón1

Title: Physical and chemical limitations
to the digestibility of tropical forages
and strategies to overcome them

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Keywords:

Limitaciones físicas y químicas
de la digestibilidad de pastos tropicales
y estrategias para aumentarla

 


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          
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   
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  
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       
          


Palabras clave:




INTRODUCCIÓN
     

 






  
       
     

    
     
      
  
   et al.  
     





     
     
 







  
     




Tabla 1. Rango en el contenido de nutrientes de diferentes clases de forrajes.
Forraje Energía metabolizable
MJ.kg-1 de MS Proteína cruda
g.kg-1 de MS
Pastos, henos y ensilajes de clima templado 7.0 – 13.0 60 – 250
Pastos tropicales 5.0 – 11.0 20 – 200
Ensilaje de maíz 10.0 – 12.0 60 – 120
Pajas de cereales 5.0 – 8.0 20 – 40
Cultivos de raíz 11.0 – 14.0 40 – 130
Fuente: Wilkins, 2000.
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Barahona y Sánchez: Limitaciones de la digestibilidad de los pastos tropicales
REVISTA CORPOICA • VOL 6 N°1 • ENERO-JUNIO 2005


     
   
       
     




et al.
 


    

     
      
      
    
        
     
  
 
      
    

      
     
      
     



 

      
      
    et al.  


     

et al.




  






    
      
   
  
    
   



      





Fibra

     
      
    
     


    
  



     
    
    
     
   
   
   
      

     
 et al.  
  
    
      
   
    

     
    
   
        
  
   
     
     

     
    
    

    






     


 

       



Consumo voluntario en pastoreo

    
  
     
et al. 
     
      
     
    

Factores físicos.   



 


  
   

      
    




 
     
      
 
et al.

    

      
     
    

    
      
      
      
   
   



et al.


     


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Barahona y Sánchez: Limitaciones de la digestibilidad de los pastos tropicales
REVISTA CORPOICA • VOL 6 N°1 • ENERO-JUNIO 2005
  
       
     
      
      
      
  
  
    

     
     
  
        
     

    
 

  
   
      

      



     
    
   
     
  
     
     
 
 
    
       
      
       
      
      

Factores metabólicos. 

 
      
 


  
      


     

Otros factores que afectan el consumo.

     


      


Manipulación del consumo en
rumiantes
     
     
    
    
      

Forrajes de baja calidad. 
    

    



      

   




      


     



      



     
     
      


   
et al.
      et
al.     
        


    
     
   
     
    


Tabla 2. Algunos de los factores vegetales y animales que afectan el consumo de rumiantes en pastoreo y circunstancias en donde pueden esperarse
consumos altos o bajos.
Factores Consumo alto Consumo bajo
Factores de las plantas
Contenido de fibra Baja fibra Alta fibra
Tipo de forraje Pastos C-3 (templados), leguminosas Pastos C-4 (tropicales)
Contenido de materia seca Ensilajes de alto contenido de materia seca Ensilajes de bajo contenido de materia seca
Estructura de la pradera Alta densidad de plantas, altura adecuada de la pradera Baja densidad de plantas, baja altura de la pradera
Conservación de forrajes Ensilaje de buena fermentación Ensilaje de mala fermentación
Factores de los animales
Estado fisiológico Animal en crecimiento Ultimo tercio de la preñez
Animal lactante Animales maduros e improductivos
Tamaño Animales grandes Animales pequeños
Tasa de consumo Características de la pradera que optimizan el tamaño del
bocado y minimizan la masticación
Características de la pradera que limitan el tamaño del
bocado y aumentan la masticación
Experiencia previa Suplementos Presencia de alcaloides, taninos condensados
Fuente: Romney y Gill, 2000
72
Barahona y Sánchez: Limitaciones de la digestibilidad de los pastos tropicales
REVISTA CORPOICA • VOL 6 N°1 • ENERO-JUNIO 2005
Figura 1. Consumo y ganancia de peso en ovinos recibiendo diferente
oferta (25, 50 ó 75 g.kg-1 de peso vivo) de paja de cebada (Preston y
Murgueitio, 1992).
Sistemas de pastoreo.
      


     


 
  
       

  

  
       
    
Brachiaria
decumbens    
   
      
     

      
     
     


   
 






 
     

Cratylia argentea

     
     

   

 C. argentea 



Factores que afectan la degradabilidad
de la fibra en rumiantes
Gramíneas versus leguminosas.  
  
    

     

     
 

     
    

Desmodium ovalifo-
lium
 D. ovalifolium Flemingia macrophylla
et al.
     

    
      
Figura 3. Relación entre el consumo voluntario y la digestibilidad de
la materia seca en leguminosas y gramíneas (Whiteman, 1980). Peso
metabólico = Peso vivo0,75.
Figura 2. Disponibilidad de forraje durante dos años de pastoreo de
una pradera de Brachiaria decumbens sola o asociada con Desmodium
ovalifolium + kudzú (D.o.) o Arachis pintoi + kudzú (A.p.); años de
pastoreo: 1998 (98) y 1999 (99); Finca Villamarina, Acacías, Meta
(Corpoica, 2001a).
73
Barahona y Sánchez: Limitaciones de la digestibilidad de los pastos tropicales
REVISTA CORPOICA • VOL 6 N°1 • ENERO-JUNIO 2005
      

      



     
et al.
      

   

    
  



      
      




     
     


  
  et al. 


      

    
 
  

     

      

    


    
     

    
     
       
 
    
  


      
  

 


    
Tabla 3. Efecto del tratamiento post-cosecha de hojas de Cratylia argentea en el consumo de
ovinos confinados en jaulas metabólicas (Raaflaub y Lascano, 1995).
Tipo de forraje Consumo de materia seca (MS) g.hora-1
Forraje inmaduro Forraje maduro
Fresco 84 291
Marchitado por 24 horas 157 376
Marchitado por 48 horas 183 ---
Secado al sol 160 359
Consumo medido por períodos de 20 minutos.
   

 
     
      
       
     
      
     
  
 
       
       


    
     

  
     
    




     
      
    
     



    

      
  






 
 


    


Barreras físicas y químicas a la degrada-
ción de fibra.      

     
 

    
 
      
     



 
     



   
       
      
   
      
  

    
    
      
       
   


     
    

     
    

     
     

       
      
     

      
    
     
       
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Barahona y Sánchez: Limitaciones de la digestibilidad de los pastos tropicales
REVISTA CORPOICA • VOL 6 N°1 • ENERO-JUNIO 2005
      
      
  




       










     
       
   

    
     

     


     



    
      








     
 

     

     

      

Mejoramiento genético. 
     
    
 
     
     

     
      

      
   
     
 Cynodon datylon,
Cenchrus ciliaris Digitaria setivalva
 
     
      
  et al.

Lolium multiflorum


     





   
      
        

       

   
     

    
     
  
    
  
  
 et al.   et
al.     
   
Tabla 4. Proporción de fracciones vegetales en dos gramíneas y su digestibilidad (DMS) a
diferentes épocas de corte.
Pasto Primer
corte Lámina foliar Envoltura foliar Tallo
Proporción DMS Proporción DMS Proporción DMS
Dactylis
glomerata
23 abril 0.67 0.79 0.21 0.81 ----- -----
29 mayo 0.27 0.70 0.19 0.65 0.29 0.65
2 julio 0.20 0.66 0.13 0.58 0.35 0.44
Lolium
perenne
27 abril 0.70 0.83 0.25 0.87 0.05 ND
19 mayo 0.31 0.82 0.16 0.77 0.34 0.75
11 junio 0.11 0.79 0.09 0.68 0.42 0.64
Fuente: Terry y Tilley, 1964.
Tabla 5. Tejidos vegetales y su digestibilidad.
Tejido Función Digestibilidad Comentarios
Mesófilo Contiene los cloroplastos Alta Pared delgada, sin lignina. Vagamente dispuesto en leguminosas y pastos C-3.
Parénquima Metabólica Moderada a alta
En la venas de las hojas en pastos y leguminosas; en la envoltura de la hoja y
tallos de los pastos y en el pecíolo y tallo de las leguminosas. Altamente dige-
rible cuando inmadura.
Colénquima Estructural Moderada a alta En hojas y tallos de leguminosas. Pared gruesa, no lignificada.
Parénquima en empalizada Contiene los cloroplastos Moderada a alta Rodea al tejido vascular en las láminas foliares de pastos C-4. Paredes mode-
radamente gruesas y débilmente lignificadas.
Fibra del floema Estructural Moderada En los pecíolos y tallos de las leguminosas. A menudo no se lignific.a
Epidermis Cobertura De baja a alta Pared exterior engrosada, lignificada y cubierta con cutícula y capa cerosa.
Tejido vascular Vascular De ninguna a
moderada
Comprende al floema y al xilema. El mayor contribuyente a la fracción indige-
rible.
Esclerénquima Estructural De ninguna a baja Hasta 1200 mm de largo y 5 – 20 mm de diámetro, gruesa, lignificada.
Fuente: Buxton y Redfearn, 1997
75
Barahona y Sánchez: Limitaciones de la digestibilidad de los pastos tropicales
REVISTA CORPOICA • VOL 6 N°1 • ENERO-JUNIO 2005
  
     
     
   

  
  Lolium perenne   
     

et al.  
     
    



     
       
 

     
 
     
   
    

      
      
     
     


   





      
   
 
       
et al.

     

   


      
        
     


      
  
      






Tabla 6. Parámetros productivos de vacas lecheras que consumieron raigrás con altos contenidos
de azúcares en la etapa final de la lactancia.
Parámetro productivo Raigrás alto en azúcar Control
Consumo total de MS, kg•día-1 15,1 14,2
Digestibilidad de la MS 0,71a0,64b
Digestibilidad del FDN 0,70a0,63b
Digestibilidad de la proteína 0,61 0,58
Consumo de N, g•día-1 280 290
Excreción de N en la orina, g•día-1 71b100a
Excreción de N en las heces, g•día-1 110 121
Excreción de N en la leche, g•día-1 83a68b
Producción de leche, kg•día-1 15,3a12,6b
Fuente: Miller et al., 2001. a, b, medias diferentes estadísticamente (P < 0,05).
Manejo de praderas.   

      
      
     




    
      
    
     
    
     
     
     
      
    



     
   
  


    


       
   
     



D. ovalifolium
et al.
     
     
  



      
  
  
  
Figura 4. Requerimientos de proteína para el mantenimiento de un
animal de 450 kg de peso que consume dietas con diferente digestibilidad
al 2% de su peso vivo (Fox et al., 1992).
76
Barahona y Sánchez: Limitaciones de la digestibilidad de los pastos tropicales
REVISTA CORPOICA • VOL 6 N°1 • ENERO-JUNIO 2005

     

    
     

in vitro



  
     
    


       

   
  
      
   


 




 
     
 
      
    
      
     
      
     
      
     


     
    
     
     
   
    


     

    
      
    




 
   

     


   

    
   

     



     
       
     




   
      
      
     
     

  
  
      
      
   
     
        
     
   
     

   et al.   
     
   
        
     

       
Pennisetum clandestinum   
     
    
     
      

      
Figura 5. Interacción genotipo x ambiente en una colección núcleo de Desmodium ovalifolium: Cambios en el contenido de fibra (FDN y FDA) en plantas
crecidas en seis diferentes sitios en Colombia bajo dos esquemas de fertilización (alta y baja). Cauca = El Melcho, Cauca, laderas secas; Chinchiná = La
Romelia (CENICAFE), Chinchiná, Caldas, laderas húmedas; Macagual = Macagual (CORPOICA), Caquetá, trópico húmedo; La Rueda = La Rueda, trópico
húmedo y Alcancía y Maquenque = Carimagua (CORPOICA), sabana bien drenada. Fuente: Schmidt et al., 2001.
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Barahona y Sánchez: Limitaciones de la digestibilidad de los pastos tropicales
REVISTA CORPOICA • VOL 6 N°1 • ENERO-JUNIO 2005

    
      


     
   

   
   
    
     



Tabla 7. Valor nutritivo de pastos en sistemas a cielo abierto o asociados con árboles en sistemas
ganaderos silvopastoriles.
Tratamiento Proteína
cruda FDN FDA Lignina DIVMS
Finca El Carmen (Valledupar, Cesar, 1999) a
Guinea a cielo abierto 8.11 68.6 42.5 11.7 53.1
Guinea asociada con Algarrobillo 9.83 64.9 39.2 10.5 63.1
Refocosta (Pivijay, Magdalena, verano de 1999) a
Guinea a cielo abierto 5.03 ------ 41.6 ------ 42.2
Guinea asociado con Eucalipto 6.48 ------ 40.7 ------ 39.4
Guinea asociado con Roble 6.04 ------ 39.3 ------ 43.7
Trópico de altura b
Kikuyo a cielo abierto 9.7 71.9 ------ 5.7 ------
Kikuyo asociado con Aliso 12.9 70.4 ------ 4.4 ------
Trópico bajo b
Colosuana a cielo abierto 4.9 65.6 37.2 6.8 ------
Colosuana asociado L. leucocephala 6.0 63.9 33.9 6.1 ------
Fuentes: a
= CORPOICA, 2001b; b = Dr. Diego Chamorro, comunicación personal.
Figura 6. Efecto de la renovación de praderas sobre la digestibilidad y la producción láctea: a) Contenido de fibra (FDN) en pasto Kikuyo de praderas
renovadas y sin renovar (control) en cuatro localidades del trópico alto colombiano [Iza y Chiquinquirá (Boyacá); Guachucal y Buesaco (Nariño)] y b)
Producción de leche en vacas pastoreando las praderas control (Trad y Com) y las renovadas (Ren1 y Ren4) en Chiquinquirá, Boyacá (hato de baja
producción) y Guachucal, Nariño (hato de alta producción). Fuente: Cuesta y Mila, 2002; Cuesta y Báez, 2003.
     

Delignificación mediante el uso de basi-
diomicetes.
     
   
       




 
    
et al.   
    
  
    
    in vitro
   
    Dichomitus squalens
Cyathus stercoreus    
   Coprinus fime-
tarius    
      
     

et al.
  
   Chaetomium
cellulolyticumet al.

     
    Cynodon
dactylon  Ceriporiopsis subvermispo-
ra  Cyathus stercoreus  et al.



      


  

      
      

    
    
     

     
  
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Barahona y Sánchez: Limitaciones de la digestibilidad de los pastos tropicales
REVISTA CORPOICA • VOL 6 N°1 • ENERO-JUNIO 2005
   et al.  

 


  

Uso de enzimas exógenas.  
     
       
     
       
 
      
       
    
et al.et al.
  et al.  

      
     
      
    et al.
et al.   et al.
et al.et al.
et al.
  
    
      
 
       
   
     
et al.

    


     
     

    

     

et al.
      
  
      
 
    
      
   

  

     
    
   

    
   
et al. 
    

in vitro
   
 
   

     


et al.

   
     

et al.
Modificación post ingestión de la degra-
dación de forrajes.    
    


     
     


   
      
  


      

    
      
    
  




Figura 7. Actividad de las CMCasas (a) y xilanasas (b) de Neocallimastix hurleyensis en la presencia de diferentes concentraciones de taninos
condensados extraídos de hojas maduras de tres leguminosas tropicales. Do = Desmodium ovalifolium ; Fm = Flemingia macrophylla ; Cc =
Calliandra calothyrsus (Theodorou et al., 2000).
79
Barahona y Sánchez: Limitaciones de la digestibilidad de los pastos tropicales
REVISTA CORPOICA • VOL 6 N°1 • ENERO-JUNIO 2005


   
 Fibrobacter succinogenes, Rumi-
nococcus flavefaciens Ruminococcus albus


     
 F. succinogenes
    

   


 
  


    
     
     
  et al.  
 

     



  
  

 

Composición de la pared celular
     
      











   
      
      

       
     et
al.      
      
    





    


    et al. 

      

  
   
in vitro
 
Leucaena


  L. leucocephala  L. pallida

    
L. macrophylla
     
     
   L. macrophylla  

  


   
    

      



Conclusiones y recomendaciones
     

    
      

     
      
        
    

      




   






     
     
     
     
 
      
     
    
      
    
     
Tabla 8. Contenido y pérdida (digestibilidad) in vitro de polisacáridos no amiláceos (PNA) en tres leguminosas tropicales del genero Leucaena
(Barahona et al., 2003).
Constituyente L. leucocephala L. pallida L. macrophylla L. leucocephala L. pallida L. macrophylla
Contenido de PNA (g•kg-1 de MS) Pérdida PNA (g•kg-1 de constituyente)
Ramnosa 6.5a3.9b0.0c774a794a-----
Arabinosa 10.3b9.5b17.2a578a578a52b
Xilosa 5.5b4.6b29.2a206b509a49b
Manosa 2.8 2.9 3.4 488a410a-79b
Galactosa 11.6 11.2 10.6 564a530a180b
Glucosa 37.8b45.9b86.9a610a690a305b
Ácidos urónicos 45.6a47.5a35.7b944a678b666b
Total PNA 120.1b125.5b183.0a717a653a297b
El contenido de componentes del PNA fue determinado pre y post incubación in vitro con microorganismos del rumen. En cada fila y dentro de cada categoría (contenido o pérdida), las medias con diferente superíndice (a
o b) son estadísticamente diferentes (P < 0,05).
80
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REVISTA CORPOICA • VOL 6 N°1 • ENERO-JUNIO 2005
       
      
    






    
     
    

       
      
     
  
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
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
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

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
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


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Lolium multiflorum
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

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
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
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
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
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Pennisetum purpureum P. typhoides
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... The inclusion of high-protein forage plants with low fiber content in the diet of bovines results in an increase in the quality of forage biomass, which, in turn, results in an increase in milk and meat production (1,2) . For this reason, an adequate and efficient propagation should be an objective of study to improve their use. ...
... The PC values found in this species are as high or even higher than those observed in some tropical legumes such as Stylosanthes guianensis (20 %) (34) , Arachis pintoi (19.7 %) (35) and Gliricidia sepium (18.23 %) (36) , and are much higher than those observed in most tropical grasses, such as Urochloa brizantha (9.3 %) (3) and Cynodon plectostachyus (9.23 %) (37) . In addition, the NDF and ADF are lower than the common values observed for tropical forages (38) , an aspect that probably does not limit voluntary consumption, the degradability of nutrients and their potential use by animals (1,3,4) . ...
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The efficient propagation of plant species with high food potential plays a fundamental role in their adoption and use by producers. It is important, therefore, to develop economical and rapid methods for the successful establishment of more productive systems. In order to know some reproductive aspects of different outstanding genotypes of T. diversifolia and thus favor its propagation and improve its use in animal feeding, its germination potential, seed production and duration of the reproductive cycle were evaluated. Forty-two (42) plots were used in a randomized complete block design with seven genotypes of T. diversifolia and two levels (without and with fertilization). Genotypes had differences in all agronomic and seed production variables except for achene drying time and rudimentary seed percentage (P<0.01). In relation to the production of true seed, fertilization had a significant effect (P<0.05) and, in general, increased the time of the phases evaluated. The highest seed production occurred in genotypes 7 and 5 and the percentage of germination had significant differences between genotypes and between pre-germinative treatments (P= 0.0001) with higher percentages in genotypes 3 and 6. It is concluded that despite the low viability of the true seed of T. diversifolia, there are genotypes with a greater potential for seed production and germination percentage, parameters that can be improved by means of pre-germinative treatments and the use of fertilizers.
... To find a classification index for the fodder material according to nutritional content, multicriteria weighted indices were adapted (Contreras et al., 2004). To obtain a level of classification, a value was assigned to each variable considering the relative importance with regard to nutritional assessment of CP, NDF, ADF, and IVDMD in consumption, use, and rumen degradability-diet composition (Van Soest, 1982;Barahona-Rosales and Sánchez-Pinzón, 2005). The Nutritional Classification Index was calculated as follows: ...
... Factors such as management, regrowth age, fertilization, cut height, phonological aspects, growth under shade, and season might have a significant effect on the nutritional value of forages (Van Soest, 1982;Velásquez et al., 2010;Santiago-Hernández et al., 2016;de Vasconcelos et al., 2019;Schnellmann et al., 2020;Tesk et al., 2020), which affects digestibility in animals (Valente et al., 2010). Variability in structural carbohydrates (NDF, ADF) in the M. maximus collection might be influenced by characteristics related to the accessions' own physiological and metabolic aspects such as the conversion efficiency of nitrogen and flowering rate (dos Costa et al., 2017), which might generate a wide range of available accessions and could be used in plant breeding programs (Deo et al., 2020) to produce or select materials with the best IVDMD ( Barahona-Rosales and Sánchez-Pinzón, 2005). ...
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The diversity and use of tropical forages for cattle feeding are the protagonists in livestock systems. The production and nutritional quality of forages represent a strategy of continuous research in animal feeding to help mitigate the environmental impact generated by tropical livestock. The objective of this study was to classify the nutritional behavior in contrasting seasons and the relationship with agronomic traits of a collection of 129 CIAT (Centro Internacional de Agricultura Tropical) accessions of Megathyrsus Maximus established in the Colombian dry tropics. By means of the near-infrared reflectance spectroscopy (NIRS) technique, crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), and in vitro dry matter digestibility (IVDMD) were determined under rainy and dry seasons as fixed effects. We measured plant height, dry matter biomass (DMB) and flowering in field. Aspects such as plant height and DMB did not show correlation with nutritional aspects, whereas flowering was correlated with the content of structural carbohydrates. Despite genotype and precipitation affecting nutritional value, there is relative nutritional steadiness in NDF, ADF, and IVDMD between seasons for some accessions. According to the cluster analysis carried out for each season, it was evidenced that from the total collection, 51.2% of the accessions during the dry season and 19.4% of the accessions during the rainy season were classified with a better nutritional profile, thus, showing a higher number of materials with better nutritional behavior in the dry season. Both the genotypic characteristics of M. maximus and environmental conditions during contrasting seasons are factors that might influence the variability of the nutritional content, productive parameters, and flowering. Additionally, fodder material classification under Hotelling's T -squared test and Nutritional Classification Index suggests accessions that might be promising for resilient nutritional quality and adequate DMB, which proves that M. maximus could become an alternative for animal feeding and sustainable livestock production during critical dry periods in tropical agroecosystems.
... In tropical countries, forages are the most economical and practical feed option for cattle, which alongside with proper management, can be available throughout the year and supply adequate nutrition. However, forage nutritional quality is highly variable, and influenced by many factors such as season, age and fertilization (12). Previous studies have reported that high fiber and lignin contents reduce the level of forage voluntary intake of grazing cattle (13,14). ...
... Diets based on feeds with high fiber contents (NDF and ADF) were less digestible, while those based on feed with low fiber contents were more digestible ( Table 1). This observation is because the amount of fiber present in forages is directly related to the increase in resistance to the reduction of forage particle size and, therefore, inversely related to its digestibility (12). Likewise, the rate of passage of the feed is inversely related to its fiber content: a high fiber content decreases the potential for DMI by increasing the feed retention time in the rumen (37,38). ...
... Los resultados de esta investigación coinciden con el estudio reportado por Batista, J., et al., (2001), quiénes consiguieron un valor medio de 2.46 % de proteína cruda, un contenido medio de 49.14 % para FDN, de 29.24 % para la FDA y 4.16 % de LDA en muestras de 60 variedades de caña de azúcar. Dependiendo de la madurez del pasto gramínea, los rumiantes pueden digerir del 60 al 70% del FDN (Rosales, R., & Pinzón, S., 2005). ...
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El objetivo fue determinar las características nutricionales de residuos de caña de azúcar (Saccharum officinarum L.) del cantón La Troncal. Se tomaron las muestras necesarias para el estudio. Se determinó la composición química, de fibras; energía bruta y degradabilidad in situ en bovinos mestizos Brahman de 450 Kg ± 20 Kg, fistulados a nivel del rumen, la incubación de las muestras se dio mediante la técnica de bolsas de nylon, manejadas durante los tiempos previstos. Resultando ser una alternativa en la alimentación animal, las características estructurales y químicas de los residuos de caña de azúcar analizadas, pueden ser utilizadas en la dieta de rumiantes debido a que mostraron un valor nutricional aceptable, con valores admisibles de degradabilidad de la materia seca in situ. Mientras tanto el contenido de fibra y porcentaje de fracción de lignina contenida, podría limitar su degradabilidad, consumo y aporte nutricional.
... However, the NDF and ADF values found in our study for both L. leucocephala and T. diversifolia are above those reported in other studies at similar sampling ages [43,45,49,50]. According to several studies [51,52] high levels of fiber constitute physical factors that limit the DM intake and degradation rate. However, similar values of NDF and ADF in L. leucocephala to those found in our study have been reported [47], and when included at 20% in the diet did not generate any effect on the DM intake. ...
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The effect of the inclusion of Leucaena leucocephala and Tithonia diversifolia in Zebu steers receiving a diet based on improved pastures such as Brachiaria decumbens and Brachiaria hybrid cv Cayman on nitrogen (N) excretion, urinary volume and rumen microbial population was evaluated. To determine the dry matter intake and nutrient excretion, eight steers were used in a 4 × 4 Latin square design consisting of four periods and four diets. Four of them were cannulated for ruminal fluid extraction and quantification of ruminal microorganisms in three times of grazing (T0, T7 and T15). Forage intake was calculated through the external marker titanium dioxide. Diet including forages with superior protein content generated an increase in the gene copy numbers of Prevotella ruminicola and total bacteria on 15 sampling day (p < 0.001). Animals receiving diets with the dietary inclusion of Leucaena and Tithonia had daily N intakes of 228 and 113.5g N intake d−1 , of which they excreted 42% and 61%, respectively. Inclusion of both protein forages increased daily urinary volume (9% and 7% d−1), with respect to the pasture-based diet. This study revealed that the inclusion of 18% Leucaena in a pasture-based diet improves the dry matter intake and N retention in Zebu steers under tropical conditions.
... In addition, one factor that can affect the fermentation and gas production of feeds is the configuration of their cell wall polysaccharides , Valencia-Salazar et al., 2021. Therefore, the digestibility values depend upon their composition of structural carbohydrates, including the concentration of lignin (Barahona and Sánchez, 2005) and FIGURE 1 | Modeled mean accumulated gas production (mL g −1 OM) for UHC, CB, LD, and 6 dietary mixtures. UHC, Cayman 100%; CB, Canavalia 100%; LD, Leucaena 100%; CB50LD50, Canavalia 50% + Leucaena 50%; UHC50CB50, Cayman 50% + Canavalia 50%; UHC50LD50, Cayman 50% + Leucaena 50%; UHC33.3CB33.3LD33.3, ...
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Forage grass nutritional quality directly affects animal feed intake, productivity, and enteric methane (CH 4 ) emissions. This study evaluated the nutritional quality, in vitro enteric CH 4 emission potential, and optimization of diets based on two widely grown tropical forage grasses either alone or mixed with legumes. The grasses Urochloa hybrid cv. Cayman (UHC) and U. brizantha cv. Toledo (UBT), which typically have low concentrations of crude protein (CP), were incubated in vitro either alone or mixed with the legumes Canavalia brasiliensis (CB) and Leucaena diversifolia (LD), which have higher CP concentrations. Substitution of 30% of the grass dry matter (DM) with CB or LD did not affect gas production or DM degradability. After 96 h of incubation, accumulated CH 4 was 87.3 mg CH 4 g ⁻¹ DM and 107.7 mg CH 4 g ⁻¹ DM for the grasses alone (UHC and UBT, respectively), and 100.7 mg CH 4 g ⁻¹ DM and 113.2 mg CH 4 g ⁻¹ DM for combined diets (70% grass, 15% CB, and 15% LD). Diets that combined legumes (CB or LC) and grass (UHC or UBT) had higher CP contents, gross, and metabolizable energy (GE, ME, respectively) densities, as well as lower concentrations of neutral detergent fiber (NDF) and acid detergent lignin (ADL). The ME and nutritional variables such as NFD, tannins (T), and CP showed a positive correlation with in vitro net gas production, while ruminal digestibility was affected by CP, ADL, T, and GE. Optimal ratios of components for ruminant diets to reduce rumen net gas production and increase protein content were found with mixtures consisting of 60% grass (either UHC or UBT), 30% CB, and 10% LD. However, this ratio did not result in a decrease in CH 4 production.
... De ello depende el estatus nutricional y la productividad de los animales (Gordon y Prins, 2008). Sin embargo, una de las mayores limitantes para lograr un óptimo incremento del CMS en sistemas ganaderos del trópico, es la baja digestibilidad de la MS en las pasturas (Barahona-Rosales y Sánchez-Pinzón, 2005). Lo anterior se debe, generalmente, a aspectos inherentes a la composición y estructura de la pared celular de los pastos con respecto a las leguminosas y a otros recursos forrajeros del trópico (Marais, 2001). ...
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