Hostname: page-component-cd9895bd7-lnqnp Total loading time: 0 Render date: 2024-12-25T07:09:31.888Z Has data issue: false hasContentIssue false
  • English
  • Français

Quantitative digestion of fresh herbage by sheep

Published online by Cambridge University Press:  27 March 2009

A. R. Egan  and
M. J. Ulyatt
A. R. Egan
Affiliation:
Department of Agronomy, Waite Agricultural Research Institute, Glen Osmond, South Australia, 5064
M. J. Ulyatt
Affiliation:
Applied Biochemistry Division, D.S.I.R. Palmerston North, New Zealand
Get access Rights & Permissions [Opens in a new window]

Summary

The utilization by sheep of dietary N provided in high protein, high water content fresh herbages (Ruanui perennial ryegrass, Tama Westerwolds ryegrass, Pitau white clover, and Fakir giant sainfoin at two stages of maturity) was studied at two levels of intake (maintenance and 1·5 maintenance). Feed was provided by constant feeder.

Apparent digestibility of N was similar for all herbages (ca. 85%) except sainfoin which, particularly at a late stage of maturity, was lower (70–80%). A small loss of nitrogen across the stomachs occurred with clover (1–3 g/day) and Tama ryegrass at the higher feeding level (2 g/day), but no loss was observed with the other diets. The apparent digestibility of N and of non-ammonia N (NAN) in the intestines was lower for sainfoin, and estimated true digestibility was also lower. Amino acid N contributed less to the NAN reaching the duodenum on the sainfoin diets than on the grass and clover diets.

N retention was negative at the lower level of feeding for ryegrass and clover diets. It was greatest for the sainfoin diets at similar N intakes, so that efficiency of retention of apparently digested N was also greatest for sainfoin.

The size of the urea pool, the plasma urea concentration and the urea irreversible loss, using [14C]urea, did not differ significantly between diets at similar N intake. Urea irreversible loss exceeded urinary urea excretion by 35—50% on all but the late-maturity sainfoin diet, where urea irreversible loss was more than double the urinary urea output. These data indicate dietary differences in the extent of degradation of urea on recycling to the gastro-intestinal tract. Urea clearance across the kidney was also lowest for sainfoin.

Data are compared in a simple model which illustrates the importance of variable clearance of urea across the kidney and the gut wall and the need for knowledge of factors which control this.

Type
Research Article
Information
The Journal of Agricultural Science , Volume 94 , Issue 1 , February 1980 , pp. 47 - 56
Copyright
Copyright © Cambridge University Press 1980

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

Ash, R. W. (1962). Gastro-intestinal re-entrant cannulae for studios of digestion in sheep. Animal Production 4, 309–312.Google Scholar
Beever, D. E., Thomson, D. J. & Cammell, S. B. (1976). The digestion of frozen and dried grass by sheep. Journal of Agricultural Science, Cambridge 86, 443–452.Google Scholar
Cocimano, M. R. & Leng, R. A. (1967). Metabolism of urea in sheep. British Journal of Nutrition 21, 353–371.Google Scholar
Egan, A. R. (1974). Protein: energy relationships in the digestion products of sheep fed on herbage diets differing in digestibility and nitrogen concentration. Australian Journal of Agricultural Research 25, 613–630.Google Scholar
Egan, A. R. & Walker, D. J. (1975). Resource allocation and ruminant protein production. In Proceedings of the 3rd World Conference on Animal Production (ed. Reid, R. L.) pp. 551–562. University of Sydney Press.Google Scholar
Egan, A. R., Walker, D. J., Nader, C. J. & Stoker, G. (1975). Comparative aspects of digestion of four roughages by sheep. Australian Journal of Agricultural Research 26, 909–922.Google Scholar
Engelhardt, W. V., Hinderer, S. & Wipper, E. (1978). Factors affecting the endogenous urea N secretion and utilization in the gastro-intestinal tract. In Ruminant Digestion and Feed Evaluation (ed. Osbourn, D. F., Beever, D. E. and Thomson, D. J.), pp. 4.1–4.12. London: Agricultural Research Council.Google Scholar
Hawk, P. B., Oser, B. L. & Summerson, W. H. (1953). Practical Physiological Chemistry, 13th edn, p. 555. N.Y.: Blakeston Corp.Google Scholar
Hemsley, J. A. (1967). Sodium chloride intake and flow from the rumen. Australian Journal of Experimental Biology and Medical Science 45, 39.Google Scholar
Kennedy, P. M. & Milligan, L. P. (1978). Transfer of urea from the blood to the rumen of sheep. British Journal of Nutrition 40, 149–154.Google Scholar
MacRae, J. C. & Ulyatt, M. J. (1974). Quantitative digestion of fresh herbage by sheep. II. The site of digestion of some nitrogenous constituents. Journal of Agricultural Science, Cambridge 82, 309–319.Google Scholar
Marsh, W. H., Fingerhut, B. & Miller, H. (1965). Automated and manual direct methods for the determination of blood urea. Clinical Chemistry 11, 624–627.Google Scholar
Mazanov, A. & Nolan, J. V. (1976). Simulation of the dynamics of nitrogen metabolism in sheep. British Journal of Nutrition 35, 149–174.Google Scholar
Nolan, J. V., Norton, B. W. & Leng, R. A. (1976). Further studies of the dynamics of nitrogen metabolism in sheep. British Journal of Nutrition 35, 127–147.Google Scholar
Nolan, J. V. & Rowe, J. B. (1976). ‘Models of N metabolism in sheep.’ In Reviews in Rural Science II, (ed. Sutherland, T. M., McWilliam, J. R. and Leng, R. A.), p. 151. Armidale: University of New England Publishing Unit.Google Scholar
Ørskov, E. R., Frazer, C., Mason, V. C. & Mann, S. O. (1970). Influence of starch digestion in the large intestine of sheep on caecal fermentation, caecal microflora, and faecal nitrogen excretion. British Journal of Nutrition 24, 671–682.Google Scholar
Osbourn, D. F., Terry, R. A., Cammell, S. B. & Outen, G. E. (1971). The effect of leuco-anthocyanins in sainfoin (Onobrychis viciifolia Scop.) on the availability of protein to sheep and upon the determination of the acid detergent fibre and lignin fractions. Proceedings of the Nutrition Society 30, 13A–14A.Google Scholar
Potter, B. J., Walker, D. J. & Forrest, W. W. (1972). Changes in intraruminal function of sheep when drinking saline water. British Journal of Nutrition 27, 75–83.Google Scholar
Smith, R. H. (1975). Nitrogen metabolism in the rumen and the composition and nutritive value of nitrogen compounds entering the duodenum. In Digestion and Metabolism in Ruminants (ed. McDonald, I. W. and Warner, A. C. I.), pp. 399–415. Armidale: University of New England Publishing Unit.Google Scholar
Thomson, D. J., Beever, D. E., Harrison, D. G., Lill, A. W. & Osbourn, D. F. (1971). The digestion of dried lucerne (Medicago sativa L.) and dried sainfoin (Onobrychis viciifolia Scop.) by sheep. Proceedings of the Nutrition Society 30, 14A–15A.Google ScholarPubMed
Thornton, R. F. (1970). Urea excretion in ruminants. Studies in sheep and cattle offered the same diet. Australian Journal of Agricultural Research 21, 323–326.Google Scholar
Ulyatt, M. J. (1971). Studies on the causes of differences in pasture quality between perennial ryegrass, short rotation ryegrass, and white clover. New Zealand Journal of Agricultural Research 14, 352–367.Google Scholar
Ulyatt, M. J. & Egan, A. R. (1979). Quantitative digestion of fresh herbage by sheep. V. The digestion of four herbages and prediction of sites of digestion. Journal of Agricultural Science, Cambridge 92, 605–616.Google Scholar
Ulyatt, M. J. & MacRae, J. C. (1974). Quantitative digestion of fresh herbage by sheep. I. The sites of digestion of organic matter, energy, readily fermentable carbohydrate, structural carbohydrate and lipid. Journal of Agricultural Science, Cambridge 82, 295–307.Google Scholar
Walker, D. J., Egan, A. R., Nader, C. J., Ulyatt, M. J. & Storer, G. B. (1975). Rumen microbial protein synthesis and proportions of microbial and non-microbial nitrogen flowing to the intestines of sheep. Australian Journal of Agricultural Research 26, 699–708.Google Scholar