My Account: Log In | Join | Renew
Search
Author
Title
Vol.
Issue
Year
1st Page

Abstract

 

This article in CS

  1. Vol. 22 No. 3, p. 564-568
     
    Received: May 29, 1981
    Published: May, 1982


 View
 Download
 Alerts
 Permissions

doi:10.2135/cropsci1982.0011183X002200030031x

Disruption of Leaf Tissues by Rumen Microorganisms: An Approach to Breeding Bloat-safe Forage Legumes

  1. R. E. Howarth,
  2. B. P. Goplen,
  3. S. A. Brandt and
  4. K. J. Cheng2

Abstract

Abstract

To develop the basic knowledge for breeding a bloat-safe alfalfa (Medicago saliva L.) cultivar, the extent of leaf tissue disruption by rumen microbes was measured using a modified nylon bag technique. Only green leaf fragments were retained for determination of undigested dry matter. Among six legume forages, the relative rates of leaf tissue disruption were: alfalfa = red clover (Trifolium pratense L.) = white clover (Trifolium repens L.) > birdsfoot trefoil (Lotus corniculatus L.) = cicer milkvetch (Astragalus cicer L.) > sainfoin (Onobrychis viciifolia Scop.). Thus the bloat-causing legumes (alfalfa, red clover, and white clover) were disrupted more rapidly than the bloat-safe legumes (birdsfoot trefoil, cicer milkvetch, and sainfoin). These results are consistent with the cell rupture theory of legume pasture bloat.

Six alfalfa cultivars (‘DuPuits’, ‘Ladak’, ‘Lahontan’, ‘Ranger’, ‘Vernal’, ‘Uinta’) had similar rates of leaf tissue disruption, and there were no differences between high- and low-saponin strains of these cultivars. However, consistent differences were detected among 11 clones (genotypes) of ‘Beaver’ alfalfa. This finding encourages further development of nylon bag digestion as a method for breeding a bloat-safe alfalfa cultivar by selection for low leaf tissue disruption. A 25 to 30% reduction in dry matter loss at 6 to 8 hours of digestion would be required to reach the bloat-safe threshold.

  Please view the pdf by using the Full Text (PDF) link under 'View' to the left.

Copyright © .

Facebook   Twitter