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The ratio of naturally occurring 13C and 12C isotopes in sheep diet and faeces as a measurement for direct determination of lucerne hay and maize grain digestibilities in mixed diets

Published online by Cambridge University Press:  27 March 2009

I. Bruckental
Affiliation:
Department of Dairy Cattle Nutrition, Institute of Animal Science, Agricultural Research Organization, The Volcani Center, P.O.B. 6, Bet Dagan 50250, Israel
A. Halevi
Affiliation:
Department of Dairy Cattle Nutrition, Institute of Animal Science, Agricultural Research Organization, The Volcani Center, P.O.B. 6, Bet Dagan 50250, Israel
S. Amir
Affiliation:
Department of Dairy Cattle Nutrition, Institute of Animal Science, Agricultural Research Organization, The Volcani Center, P.O.B. 6, Bet Dagan 50250, Israel
H. Neumark
Affiliation:
Department of Dairy Cattle Nutrition, Institute of Animal Science, Agricultural Research Organization, The Volcani Center, P.O.B. 6, Bet Dagan 50250, Israel
Hanna Kennit
Affiliation:
Department of Dairy Cattle Nutrition, Institute of Animal Science, Agricultural Research Organization, The Volcani Center, P.O.B. 6, Bet Dagan 50250, Israel
G. Schroeder
Affiliation:
Department of Dairy Cattle Nutrition, Institute of Animal Science, Agricultural Research Organization, The Volcani Center, P.O.B. 6, Bet Dagan 50250, Israel

Summary

Two experiments were conducted with eight rams in a latin-square design of four treatments with different lucerne hay (LH): maize grain (MG) ratios: 100:0, 80:20, 50:50 and 20:80. In Expt 1 the amount of food offered was restricted to 1 kg/day. In Expt 2 the rams were offered 1·5 kg/day, which was about the maximum amount the animals in the 100% LH treatment were able to consume. Animals were kept on each treatment for 4 weeks; during the final 8 days the faeces were oollected and weighed for each animal and analysed for dry matter, organic matter (OM), crude fibre and δC

The values of δC in LH, MG and different faeces samples were used for direct determination of LH and MG digestibilities of mixed diets in the different treatments.

The increase of MG in the ration and the decrease of LH improved the digestibility of total OM. The effect of MG was more pronounced at the low than at the high level of consumption. At the low level of intake, an increase in the amount of MG in the ration did not affect the digestibility of LH, and MG digestibility was close to the extrapolated value. At a food intake level 1·5 times that of Expt 1, the addition of grain to more than 50 % of the ration caused a marked depression in digestibility of LH.

Results of the δC method were discussed in comparison with calculated values of LH and MG digestibilities and with whole ration crude-fibre digestibility.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1985

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References

Craig, H. (1957). Isotopic standards for carbon and oxygen and correction factors for mass-spectrometric analysis of CO2. Qeochimica Cosmochimica, Acta 12, 133149.CrossRefGoogle Scholar
Joanning, S. W., Johnson, D. E. & Barry, B. P. (1981). Nutrient digestibility depressions in corn silage-corn grain mixtures fed to steers. Journal of Animal Science 53, 10951103.CrossRefGoogle Scholar
Jones, R. J., Ludlow, M. M., Troughton, J. H. & Blunt, C. G. (1979). Estimation of the proportion of C3 and C4 plant species in the diet of animals from the ratio of natural 18C and 13C isotopes in the faeces. Journal of Agricultural Science, Cambridge 92, 91100.CrossRefGoogle Scholar
Minson, D. J., Ludlow, M. M. & Troughton, J. H. (1975). Differences in natural carbon isotope ratios of milk and hair from cattle grazing tropical and temperate pastures. Nature 256, 602.CrossRefGoogle ScholarPubMed
Robertson, J. B. & Van Soest, P. J. (1975). A note on digestibility in sheep as influenced by level of intake. Animal Production 21, 8992.Google Scholar
Schboeder, G. (1983a). Stable isotope ratios as naturally occurring tracers in the aquaculture food web. Aquaculture 30, 203210.CrossRefGoogle Scholar
Schroeder, G. (1983b). Sources of fish and prawn growth in polyculture ponds as indicated by SC analysis. Aquaculture 35, 2942.CrossRefGoogle Scholar
Tyrrell, H. F. & Moe, P. W. (1975). Effect of intake on digestive efficiency. Journal of Dairy Science 58, 11511163.CrossRefGoogle Scholar
Wagner, D. G. & Loosli, J. K. (1967). Studies on the energy requirements of high producing dairy cows. Memoir no.400, pp. 340. Cornell University, Agricultural Experimental Station, N.Y.Google Scholar