Hostname: page-component-586b7cd67f-t7czq Total loading time: 0 Render date: 2024-11-28T21:30:02.312Z Has data issue: false hasContentIssue false
  • English
  • Français

Summer-growing components of a pasture system in a subtropical environment. 2. Relations between pasture and animal production

Published online by Cambridge University Press:  27 March 2009

G. J. Murtagh ,
A. G. Kaiser  and
D. O. Huett
G. J. Murtagh
Affiliation:
Agricultural Research Centre, Wollongbar, N.S.W. 2480, Australia
A. G. Kaiser
Affiliation:
Agricultural Research Centre, Wollongbar, N.S.W. 2480, Australia
D. O. Huett
Affiliation:
Agricultural Research Centre, Wollongbar, N.S.W. 2480, Australia
Get access Rights & Permissions [Opens in a new window]

Summary

Relations were developed between the carrying capacity or production of fat-corrected milk (FCM)/ha and various measures of pasture growth for six pasture treatments grown in a subtropical environment. The pasture and animal production variables were obtained from pastures grazed on a weekly rotation using stocking densities which were varied so that a target weight of leaf material remained on the pasture at the conclusion of each grazing.

Within a treatment, there was a curvilinear relation between the rate of leaf growth and carrying capacity, with the greatest efficiency of conversion at the lowest leaf growth rates. This relation generally varied between pasture treatments because of differences in grazing intensity. There was little variation in the production of FCM per cow between grazing periods within a treatment, reflecting the experimental technique of matching the stocking density to the amount of forage. Consequently FCM/ha largely mirrored the stocking density with some adjustment for differences in production per cow caused by differences in grazing intensity between treatments. Production of FCM/ha was affected more by a unit change in residue leaf yield than by a unit change in leaf yield before grazing.

Using the rate of leaf removal (intake plus grazing losses) per cow as an inverse index of grazing intensity, it was apparent that the use of variable stocking densities to obtain specified residue yields after grazing did not necessarily equalize the grazing intensity because the rate of leaf removal per cow varied according to the before-grazing leaf yield. Also soiling by dung caused differences in the acceptability of forage for grazing, resulting in differences in grazing intensity between pastures with the same yield and stocking density.

Type
Research Article
Information
The Journal of Agricultural Science , Volume 94 , Issue 3 , June 1980 , pp. 665 - 674
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

Blaser, R. E., Bryant, H. T., Ward, C. Y., Hammes, K. C., Carter, R. C. & MacLeod, N. H. (1959). Symposium on forage evaluation. VII. Animal performance and yields with methods of utilizing pasturage. Agronomy Journal 51, 238–242.Google Scholar
Chacon, E. & Stobbs, T. H. (1976). Influence of progressive defoliation of a grass sward on the eating behaviour of cattle. Australian Journal of Agricultural Research 27, 709–727.Google Scholar
Conway, A. G. (1973). Voluntary intake and stocking rate equivalents for grazing cattle. Irish Journal of Agricultural Research 12, 193–204.Google Scholar
Greenhalgh, J. F. D. & Reid, G. W. (1969). The effects of grazing intensity on herbage consumption and animal production. III. Dairy cows grazed at two intensities on clean or contaminated pasture. Journal of Agricultural Science, Cambridge 72, 223–228.Google Scholar
Murtagh, G. J. (1975). The need for alternative techniques of productivity assessment in grazing experiments. Tropical Grasslands 9, 151–158.Google Scholar
Murtagh, G. J., Kaiser, A. G., Huett, D. O. & Hughes, R. M. (1980). Summer-growing components of a pasture system in a subtropical environment. 1. Pasture growth, carrying capacity and milk production. Journal of Agricultural Science, Cambridge 94, 645–663.Google Scholar
Raymond, W. F. (1966). The measurement of pasture output. Proceedings of the Nutrition Society 16, 20–25.Google Scholar
Spedding, C. R. W. (1970). The relative complexity of grassland systems. Proceedings of the 11th International Grassland Congress, pp. A126–131.Google Scholar
Stobbs, T. H. (1971). Quality of pasture and forage crops for dairy production in the tropical regions of Australia. 1. Review of the literature. Tropical Grasslands 5, 159–170.Google Scholar
Stobbs, T. H. (1973). The effect of plant structure on the intake of tropical pastures. I. Variation in the bite size of grazing cattle. Australian Journal of Agricultural Research 24, 809–819.Google Scholar
Tayler, J. C. (1966). Relationships between the herbage consumption or carcass energy increment of grazing beef cattle and the quantity of herbage on offer. Proceedings of the 10th International Grassland Congress, pp. 463–470.Google Scholar
Williams, E. J. (1959). Regression Analysis. New York: John Wiley.Google Scholar