Hostname: page-component-77c89778f8-m8s7h Total loading time: 0 Render date: 2024-07-19T07:14:32.275Z Has data issue: false hasContentIssue false

The potential for using n-alkanes in tropical forages as a marker for the determination of dry matter by grazing ruminants

Published online by Cambridge University Press:  27 March 2009

M. A. Laredo
Affiliation:
Division of Tropical Crops and Pastures, CSIRO, Cunningham Laboratory, 306 Carmody Road, St Lucia, Brisbane, Queensland 4067, Australia
G. D. Simpson
Affiliation:
Division of Tropical Crops and Pastures, CSIRO, Cunningham Laboratory, 306 Carmody Road, St Lucia, Brisbane, Queensland 4067, Australia
D. J. Minson
Affiliation:
Division of Tropical Crops and Pastures, CSIRO, Cunningham Laboratory, 306 Carmody Road, St Lucia, Brisbane, Queensland 4067, Australia
C. G. Orpin
Affiliation:
Division of Tropical Crops and Pastures, CSIRO, Cunningham Laboratory, 306 Carmody Road, St Lucia, Brisbane, Queensland 4067, Australia

Summary

The intake of temperate forages by herbivores can be determined using the C33 alkane naturally present in the forage and dosed C32 alkane. To determine whether the technique can be used with tropical forages, the concentrations of C33 alkane were determined in seven species.

The leaves of Brachiaria decumbens, Digitaria decumbens, Pennisetum glaucum and Stylosanthes scabra contained sufficient C33 alkane (> 50 mg/kg DM) for the estimation of dry matter intake. Low concentrations of C33 alkane were found in the leaves of Setaria sphacelata, Sorghum sp. and Leucaena leucocephala. Setaria sphacelata was found to contain high concentrations of C27 alkane and therefore intake could be estimated by using C28 as the dosed alkane although the intake would possibly then be underestimated by c. 8%. Leaves of Sorghum sp. contained > 50 mg C31 alkane/kg DM and, with C32 as the dosed alkane, intake would possibly be underestimated by c. 5%. Leucaena leucocephala contained insufficient alkanes to estimate forage intake. The concentration of n-alkanes in Pennisetum glaucum and Sorghum sp. leaves decreased with age.

It was concluded that some tropical forages contain insufficient C33 alkane for the measurement of intake by the double alkane technique. In these species, a shorter chain length alkane can sometimes be used, but only with a reduction in accuracy in estimating intake.

Type
Animals
Copyright
Copyright © Cambridge University Press 1991

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

Casson, T., Rowe, J. B., Thorn, C. W. & Harris, D. (1990). The use of natural n-alkanes in medic and clover as indigestible markers. Proceedings of the Australian Society of Animal Production 18, 462.Google Scholar
Dove, H., Foot, J. Z. & Freer, M. (1989 a). Estimation of pasture intake in grazing ewes, using the alkanes of plant cuticular waxes. In Proceedings of the XVIth International Grassland Congress, pp. 10911092. Nice, France: Association Francaise pour la Production Fourragere, INRA.Google Scholar
Dove, H., Mayes, R. W., Freer, M., Coombe, J. B. & Foot, J. Z. (1989 b). Faecal recoveries of the alkanes of plant cuticular waxes in penned and in grazing sheep. In Proceedings of the XVIth International Grassland Congress, pp. 10931094, Nice, France: Association Francaise pour la Production Fourragere, INRA.Google Scholar
Dove, H., Milne, J. A. & Mayes, R. W. (1990). Comparison of herbage intakes estimated from in vitro- or alkanebased digestibilities. Proceedings of the New Zealand Society of Animal Production 50, 457459.Google Scholar
Langlands, J. P. (1975). Techniques for estimating nutrient intake and its utilisation by the grazing ruminants. In Digestion and Metabolism in the Ruminant (Eds McDonald, I. W. & Warner, A. C. I.), pp. 320332. Armidale: University of New England.Google Scholar
Mayes, R. W., Lamb, C. S. & Colgrove, P. M. (1986). The use of dosed and herbage n-alkanes as markers for the determination of herbage intake. Journal of Agricultural Science, Cambridge 107, 161170.CrossRefGoogle Scholar
Minson, D. J. (1990). Forage in Ruminant Nutrition. San Diego: Academic Press.Google Scholar
Wilson, J. R. (1976). Variation of leaf characteristics with level of insertion on a grass tiller. I. Development rate, chemical composition and dry matter digestibility. Australian Journal of Agriculture Research 27, 343354.CrossRefGoogle Scholar