Hostname: page-component-848d4c4894-ttngx Total loading time: 0 Render date: 2024-05-19T13:23:54.729Z Has data issue: false hasContentIssue false

Effect of species composition and sward structure on the ingestive behaviour of cattle and sheep grazing South African sourveld

Published online by Cambridge University Press:  27 March 2009

P. J. O'Reagain
Affiliation:
Dohne Agricultural Development Institute, Private Bag XI5, Stutterheim 4930, South Africa
B. C. Goetsch
Affiliation:
Dohne Agricultural Development Institute, Private Bag XI5, Stutterheim 4930, South Africa
R. N. Owen-Smith
Affiliation:
Centre for African Ecology, University of the Witwatersrand, PO Wits 2050, South Africa

Summary

The effects of species composition and sward structure on the ingestive behaviour of cattle and sheep grazing a mesic, low quality grassland in South Africa were investigated over the 1990–93 grazing seasons. Species composition had a significant (P < 0·05) effect on sheep bite size and on cattle and sheep bite rates but had no effect on dry matter intake rate (IR). Species composition could, however, affect IR over longer grazing periods than those used in the experiment.

Sward structure had a major effect on ingestive behaviour. Cattle and sheep bite rates and cattle grazing time, were negatively correlated (P < 0·05) with plant height but positively correlated (P < 0·05) with sward greenness. Bite size and hence IR in cattle and sheep were strongly correlated (P < 0·001) with plant height. Cattle IR increased from 6 to 20g/min over the range of heights encountered and appeared to reach an asymptote at a plant height of 20–25 cm. Sheep IR, expressed per unit of body mass, increased from 0·01 to an asymptote or maximum of 0·13 g/min/kg at plant heights of 10–15 cm. For sheep there was evidence of a non-asymptotic functional response at some sites with IR being maximized at certain sward heights but declining thereafter. This suggests the possible existence of a third, quality dimension to the functional response on these low-quality grasslands.

Type
Animals
Copyright
Copyright © Cambridge University Press 1996

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

Acocks, J. P. H. (1988). Veld types ofSouth Africa. Memoirs of the Botanical Survey of South Africa 57. Pretoria: Government Printer.Google Scholar
Allden, W. G. & Whittaker, I. A. McD. (1970). The determinants of herbage intake by grazing sheep: the interrelationship of factors influencing herbage intake and availability. Australian Journal of Agricultural Research 21, 755766.CrossRefGoogle Scholar
Arnold, G. W. (1962). Effects of pasture maturity on the diet of sheep. Australian Journal of Agricultural Research 13, 701706.CrossRefGoogle Scholar
Black, J. L. & Kenney, P. A. (1984). Factors affecting diet selection by sheep. II. Height and density of pasture. Australian Journal of Agricultural Research 35, 565578.CrossRefGoogle Scholar
Chacon, E. A., Stobbs, T. H. & Dale, M. B. (1978). Influence of sward characteristics on grazing behaviour and growth of Hereford steers grazing tropical grass pastures. Australian Journal of Agricultural Research 29, 89102.CrossRefGoogle Scholar
Hardy, M. G. (1986). Grazing dynamics in highland sourveld. M.Sc. thesis, University of Natal, Pietermaritzburg.Google Scholar
Hodgson, J. (1981). Influence of sward characteristics on diet selection and herbage intake by the grazing animal. In Nutritional Limits to Animal Production from Pastures (Ed. Hacker, J. B.), pp. 153166. Proceedings of the International Congress held at St. Lucia, Queensland, Australia. St. Lucia: Commonwealth Agricultural Bureau.Google Scholar
Holling, C. S. (1959). Some characteristics of simple types of predation and parasitism. Canadian Entomologist 91, 385398.CrossRefGoogle Scholar
Laca, E. A. & Demment, M. W. (1991). Herbivory: the dilemma of foraging in a spatially heterogenous food environment. In Plant Defences Against Mammalian Herbivores (Ed. Palo, R. T. & Robbins, C. T.), pp. 2944. Boca Raton: CRC Press.Google Scholar
Laca, E. A., Ungar, E. D., Seligman, N. & Demment, M. W. (1992). Effects of sward height and bulk density on bite dimensions of cattle grazing homogeneous swards. Grass and Forage Science 47, 91102.CrossRefGoogle Scholar
Langlands, J. P. & Sanson, J. (1976). Factors affecting the nutritive value of the diet and the composition of rumen fluid in grazing sheep and cattle. Australian Journal of Agricultural Research 27, 691707.CrossRefGoogle Scholar
Mangel, M. & Clark, C. W. (1986). Towards a unified foraging theory. Ecology 67, 11271138.CrossRefGoogle Scholar
McNaughton, S. J. (1984). Grazing lawns: animals in herds, plant form and co-evolution. American Naturalist 126, 863886.CrossRefGoogle Scholar
Mentis, M. T. (1982). A simulation of the grazing of sour grassveld. PhD thesis, University of Natal, Pietermaritzburg.Google Scholar
Newman, J. A., Penning, P. D., Parsons, A. J., Harvey, A. & Orr, R. J. (1994). Fasting affects intake behaviour and diet preference of grazing sheep. Animal Behaviour 47, 185193.CrossRefGoogle Scholar
O'Reagain, P. J. (1990). The relationship between sward structure, ingestive behaviour and dietary quality in cattle grazing a Chloris gayana pasture. Journal of the Grassland Society of Southern Africa 7, 133138.CrossRefGoogle Scholar
O'Reagain, P. J. (1994). The effect of sward structure and species composition on dietary quality and intake in cattle and sheep grazing the Dohne Sourveld. PhD thesis, University of the Witwatersrand, Johannesburg.Google Scholar
O'Reagain, P. J. & Grau, E. A. (1995). Sequence of species selection by cattle and sheep grazing South African sourveld. Journal of Range Management 48, 314321.CrossRefGoogle Scholar
O'Reagain, P. J. & Owen-Smith, R. N. (1996). Effect of species composition and sward structure on dietary quality in cattle and sheep grazing South African sourveld. Journal of Agricultural Science, Cambridge 127, 261270.CrossRefGoogle Scholar
Owen-Smith, R. N. (1993). Evaluating optimal diet models for an African browsing ruminant, the kudu: how constraining are the assumed constraints? Evolutionary Ecology 7, 499524.CrossRefGoogle Scholar
Penning, P. D. & Hooper, G. E. (1985). An evaluation of the use of short-term weight changes in grazing sheep for estimating herbage intake. Grass and Forage Science 40, 7984.CrossRefGoogle Scholar
Penning, P. D., Parsons, A. J., Orr, R. J. & Treacher, T. T. (1991 a). Intake and behaviour responses by sheep to changes in sward characteristics under continuous stocking. Grass and Forage Science 46, 1528.CrossRefGoogle Scholar
Penning, P. D., Rook, A. J. & Orr, R. J. (1991 b). Patterns of ingestive behaviour of sheep continuously stocked on monocultures of ryegrass or white clover. Applied Animal Behavioural Science 31, 231250.CrossRefGoogle Scholar
Ruyle, G. B., Hasson, O. & Rice, R. W. (1987). Influence of residual stems on biting rates of cattle grazing Eragrostis lehmanniana Nees. Applied Animal Behavioural Science 19, 1117.CrossRefGoogle Scholar
SAS Institute (1991). SAS/STAT User's Guide, Release 6.03, 6th Edn. Cary, NC: SAS Institute.Google Scholar
Spalinger, D. E. & Hobbs, N. T. (1992). Mechanics of foraging in mammalian herbivores: new models of functional response. American Naturalist 140, 325348.CrossRefGoogle 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, 809819.CrossRefGoogle Scholar
Stobbs, T. H. (1974). Rate of biting by Jersey cows as influenced by the yield and maturity of pasture swards. Tropical Grasslands 8, 8186.Google Scholar
Tainton, N. M. (1986). A system for assessing range condition in South Africa. In Rangelands: a Resource Under Siege (Eds Joss, P. J., Lynch, P. W. & Williams, O. B.), p. 524. Proceedings of the 2nd International Rangeland Congress. Canberra: Australian Academy of Sciences.Google Scholar
Ungar, E. D. & Noy-Meir, I. (1988). Herbage intake in relation to availability and sward structure: grazing processes and optimal foraging. Journal of Applied Ecology 25, 10451062.CrossRefGoogle Scholar
Wickstrom, M. L., Robbins, C. T., Hanley, T. A., Spalinger, D. E. & Parish, S. M. (1984). Food intake and foraging energetics of elk and mule deer. Journal of Wildlife Management 48, 12851301.CrossRefGoogle Scholar