Hostname: page-component-78c5997874-xbtfd Total loading time: 0 Render date: 2024-11-05T14:57:11.425Z Has data issue: false hasContentIssue false
  • English
  • Français

Voluntary consumption of forage by sheep and its relation to the size and shape of particles in the digestive tract

Published online by Cambridge University Press:  02 September 2010

J. E. Troelsen  and
J. B. Campbell
J. E. Troelsen
Affiliation:
Research Station, Canada Department of Agriculture, Swift Current, Saskatchewan, Canada
J. B. Campbell
Affiliation:
Research Station, Canada Department of Agriculture, Swift Current, Saskatchewan, Canada
Get access

Extract

Two alfalfa varieties and four grass species were harvested for hay at several stages of maturity. Each hay was given to sheep to provide measures of voluntary consumption and digestibility. Digesta samples were obtained from the reticulo-rumen, omasum and abomasum by killing the sheep at the end of the feeding periods.

Sieving analyses of the digesta revealed that the fraction retained by a 0·25-mm sieve provided greater differentiation between experimental treatments than those retained by 0·5-, 1·0- or 2·0-mm sieves. The weight percentage of this fraction was used as a measure of the relative particle size despite its profound dependence on size, shape, density and distribution of individual particles.

The variation in relative particle size of digesta from different sheep fed on the same diet was illustrated by coefficients of variation ranging from 4 to 11%. Four replicates, however, were sufficient to detect numerous differences (P<0·05) between experimental treatments.

Omasal digesta from alfalfa hay had a greater relative particle size than those from the grass hays at comparablematuritystages. This may be attributable to an apparently more compact particle shape observed in the alfalfa digesta, assuming that in a simple physical sieving process the most compact particle passing a given opening will have the greatest mass. It was proposed that digesta particle shape may have greater specific importance than relative particle size for the rate of passage and voluntary intake of coarse roughage.

A direct relationship was observed between voluntary feed consumption and the relative particle size of omasal digesta from different grass hays at similar maturity stages. This was the reverse of that observed between different maturity stages within hay species. It was hypothesized that the former relationship was due mainly to changing mass of the individual particles passing the reticulo-omasal opening, whereas the latter relationship was caused mainly by the particle size distribution.

The relationship between the relative particle size of digesta from the reticulo-rumen and that of digesta from the omasum supports the theory that the reticulo-omasal opening is the site of major obstruction for the passage of coarse roughage through the digestive system of ruminants.

Type
Research Article
Information
Animal Production , Volume 10 , Issue 3 , August 1968 , pp. 289 - 296
Copyright
Copyright © British Society of Animal Science 1968

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Balch, C. C. and Campling, R. C. 1962. Regulation of voluntary food intake in ruminants. Nutr. Abstr. Rev. 32: 669–686.Google ScholarPubMed
Balch, C. C. and Campling, R. C. 1965. Rate of passage of digesta through the ruminant digestive tract. In Physiology of Digestion in the Ruminant (ed. Dougherty, R. W.). Butterworth's, Washington, D.C.Google Scholar
Blaxter, K.L. 1950. Energy feeding standards for dairy cattle. Nutr. Abstr. Rev. 20: 1–21.Google Scholar
Blaxter, K. L., Wainman, F. W. and Wilson, R. S. 1961. The regulation of food intake by sheep. Anim. Prod. 3: 51–61.Google Scholar
Bourget, S. J. and Kemp, J. D. 1957. Wet sieving apparatus for stability analyses of soil aggregates. Can. J. Soil Sci. 37: 60.CrossRefGoogle Scholar
Conrad, H. R., Pratt, A. D. and Hibbs, J. W. 1964. Regulation of feed intake in dairy cows. I. Change in the importance of physical and physiological factors with increasing digestibility. J. Dairy Sci. 47: 54–62.CrossRefGoogle Scholar
Drapala, W. J., Raymond, L. C. and Crampton, E. W. 1947. Pasture studies. XXVII. The effects of maturity of the plant and its lignification and subsequent digestibility by animals as indicated by methods of plant histology. Sci. Agr. 27: 36–41.Google Scholar
Ingalls, J. R., Thomas, J. W., Tesar, M. B. and Carpenter, D. L. 1966. Relations between ad libitum intake of several forage species, and gut fill. J. Anim. Sci. 25: 283–289.CrossRefGoogle Scholar
Keford, N. P. 1958. Lignification of plants in relation to ruminant nutrition. J. Aust. Inst. agric. Sci. 24: 297–302.Google Scholar
National Research Council 1964. Joint US-Canadian tables of feed composition. Publ. National Research Council, Washington, no. 1232.Google Scholar
Osbourn, D. F., Thomson, D. J. and Terry, R. A. 1966. The relationship between voluntary intake and digestibility of forage crops, using sheep. Proc. 10th int. Grassld Congr., Helsinki.Google Scholar
Pigden, W. J. 1953. The relation of lignin, cellulose, protein, starch and ether extract to the ‘curing’ of range grasses. Can. J. agric. Sci. 33: 364–378.Google Scholar
Snedecor, G. W. 1956. Statistical Methods, 5th ed.Iowa State College Press, Ames, la.Google Scholar
Troelsen, J. E. 1967. Systems for estimating the nutritional quality of hay for domestic ruminants. Ph.D. Thesis. University of Saskatchewan.Google Scholar
Troelsen, J. E. and Bigsby, F. W. 1964. Artificial mastication—a new approach for predicting voluntary forage consumption by ruminants. J. Anim. Sci. 23: 1139–1142.CrossRefGoogle Scholar
Welch, J. G. 1965. Effect of undigestible fibers on intake of hay by sheep. J. Anim. Sci. 24: 911 (Abstr.).Google Scholar