Hostname: page-component-848d4c4894-mwx4w Total loading time: 0 Render date: 2024-06-17T19:12:52.362Z Has data issue: false hasContentIssue false
  • English
  • Français

Effect of herbage in Astrebla spp. pastures in northwest Queensland on lamb survival

Published online by Cambridge University Press:  27 March 2009

D. H. Cobon  and
J. O. Carter
D. H. Cobon
Affiliation:
Queensland Department of Primary Industries, Toorak Research Station, Julia Creek, Qld 4823, Australia
J. O. Carter
Affiliation:
Queensland Department of Primary Industries, Toorak Research Station, Julia Creek, Qld 4823, Australia
Get access Rights & Permissions [Opens in a new window]

Summary

Extensive grazing experiments were conducted over four summer breeding seasons in north-west Queensland between 1984 and 1989. Ewes in the last third of pregnancy were grazed on Mitchell grass (Astrebla spp.) pastures of varying forb (herbaceous plant other than a grass) content. Pastures of low forb content (F-) were attained by stocking paddocks heavily with wethers prior to the experiment, or by selecting paddocks which already contained pastures of low forb content. Pastures of high forb content (F+) were kept without animals prior to the experimental period. Pastures comprised a range of forb biomass (29–828 kg DM/ha) and percentage forbs in total biomass (3–49%). Lamb marking percentage was found to be dependent on the biomass of forbs and proportion of forbs in the pasture, in two experiments. Ewes which grazed F+ pastures had lower lamb marking percentages than those grazing F- pastures.

Twenty pasture species collected during the experiments were analysed for the ratio of 13C: 12C and photosynthetic pathway was determined. Five forb and all three grass species had C4-dicarboxylic acid pathways, ten forbs had Calvin-C3 pathways and two forbs had crassulacean acid metabolism pathways.

Estimates of the proportion of C3 and C4 species in the diet were determined by analysing the ratio of 13C:12C in faeces. The apparent high proportion of Calvin-C3 pathway forbs in the diet of ewes compared to the proportion in the total pasture biomass indicated that ewes preferentially select C3 forbs in the diet, although there was no dependence of lambing percentage on the estimated proportion of C3 forbs in the diet. Management strategies that may improve lambing percentage in the Mitchell grass areas of north-west Queensland are discussed.

Type
Animals
Information
The Journal of Agricultural Science , Volume 122 , Issue 2 , April 1994 , pp. 291 - 298
Copyright
Copyright © Cambridge University Press 1994

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

Australian Bureau of Statistics (1960–1989). Sheep: Lambings, Losses and Turnoff in Local Government Areas by Statistical Divisions, Queensland. Canberra: Australian Bureau of Statistics.Google Scholar
Broadmeadow, A. C. C., Cobon, D. H., Hopkins, P. S. & O'Sullivan, B. M. (1984). Effects of plant toxins on perinatal viability in sheep. In Reproduction in Sheep (Eds Lindsay, D. R. & Pearce, D. T.), pp. 216–219. Canberra: Academy of Science.Google Scholar
Entwistle, K. W. (1972). Early reproductive failure in ewes in a tropical environment. Australian Veterinary Journal 48, 395–401.CrossRefGoogle Scholar
Graetz, R. D. & Wilson, A. D. (1980). Comparison of the diets of sheep and cattle grazing a semi-arid chenopod shrubland. Australian Rangeland Journal 2, 67–75.CrossRefGoogle Scholar
Hopkins, P. S., Nolan, C. J. & Pepper, P. M. (1980). The effects of heat stress on the development of the foetal lamb. Australian Journal of Agricultural Research 31, 763–771.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 12C and 13C isotopes in the faeces. Journal of Agricultural Science, Cambridge 92, 91–100.CrossRefGoogle Scholar
Leigh, J. H. & Holgate, M. D. (1978). Effects of pasture availability on the composition and quality of the diet selected by sheep grazing native, degenerate and improved pastures in the Upper Shoalhaven Valley, New South Wales. Australian Journal of Experimental Agriculture and Animal Husbandry 18, 381–390.CrossRefGoogle Scholar
Leigh, J. H. & Mulham, W. E. (1964). Dietary preferences of sheep in two semi-arid pastoral eco-systems. Proceedings of the Australian Society of Animal Production 5, 251–255.Google Scholar
Lorimer, M. S. (1976). Forage selection by sheep grazing Mitchell grass pastures in north west Queensland. MAgrSc thesis, University of Queensland, Brisbane.Google Scholar
Lorimer, M. S. (1978). Forage selection studies. 1. The botanical composition of forage selected by sheep grazing Astrebla spp. pasture in north-west Queensland. Tropical Grasslands 12, 97–108.Google Scholar
Ludlow, M. M., Troughton, J. H. & Jones, R. J. (1976). A technique for determining the proportion of C3 and C4 species in plant samples using stable natural isotopes of carbon. Journal of Agricultural Science, Cambridge 87, 625–632.CrossRefGoogle Scholar
McMeniman, N. P., Beale, I. F. & Murphy, G. M. (1986). Nutritional evaluation of south-west Queensland pastures. 1. The botanical and nutrient content of diets selected by sheep grazing on Mitchell grass and mulga/grassland associations. Australian Journal of Agricultural Research 37, 289–302.CrossRefGoogle Scholar
Moule, G. R. (1954). Observations on mortality amongst lambs in Queensland. Australian Veterinary Journal 30, 153–171.Google Scholar
Norton, B. W. & Hales, J. W. (1981). A field technique for identifying lambs with dams in large flocks. The Journal of the Australian Institute of Agricultural Science 47, 52–54.Google Scholar
Orr, D. M., Evenson, C. J., Jordan, D. J., Bowly, P. S., Lehane, K. J. & Cowan, D. C. (1988). Sheep productivity in an Astrebla grassland of south-west Queensland. Australian Rangelands Journal 10, 39–47.CrossRefGoogle Scholar
Pratt, M. S. & Hopkins, P. S. (1975). The diagnosis of pregnancy in sheep by abdominal palpation. Australian Veterinary Journal 51, 378–380.CrossRefGoogle ScholarPubMed
Pritchard, D. A. (1986). Some studies on the productivity of high and low wool producing sheep in western Queensland. MSc thesis, James Cook University, Townsville.Google Scholar
Radford, H. M., Watson, R. H. & Wood, G. E. (1960). A crayon and associated harness for the detection of mating under field conditions. Australian Veterinary Journal 36, 57–66.CrossRefGoogle Scholar
Rose, M. (1972). Vital statistics for an experimental flock of Merino sheep in north west Queensland. Proceedings of the Australian Society of Animal Production 9, 48–54.Google Scholar
Shomer-Ilan, A., Nissenbaum, A. & Waisel, Y. (1981). Photosynthetic pathways and the ecological distribution of the Chenopodiaceae in Israel. Oecologia 48, 244–248.CrossRefGoogle Scholar
Squires, V. R. (1980). Chemical and botanical composition of the diets of oesophageally fistulated sheep, cattle and goats in a semi-arid Eucalyptus populnea woodland community. Australian Rangeland Journal 2, 94–103.CrossRefGoogle Scholar
Stephenson, R. G. A., Hooley, R. D., Findlay, J. K. & Hopkins, P. S. (1980). Effects of heat stress on the lactation performance of ewes accustomed to tropical conditions and the total fluid intake of their lambs. Australian Journal of Biological Sciences 33, 449–456.CrossRefGoogle ScholarPubMed
Stephenson, R. G. A., Edwards, J. C. & Hopkins, P. S. (1981). The use of urea to improve milk yields and lamb survival of Merinos in a dry tropical environment. Australian Journal of Agricultural Research 32, 497–509.CrossRefGoogle Scholar
Stephenson, R. G. A., Suter, G. R. & Le Feuvre, A. S. (1984). Reduction of the effects of heat stress on lamb birth weight and survival by provision of shade. In Reproduction in Sheep (Eds Lindsay, D. R. & Pearce, D. T.), pp. 223–225. Canberra: Academy of Science.Google Scholar
Tothill, J. C., Hargreaves, J. N. G.& Jones, R. M. (1978). Botanal: A Comprehensive Sampling and Computing Procedure for Estimating Pasture Yield and Composition. Field Sampling. CSIRO Tropical Agronomy Technical Memorandum (8), CSIRO, Division of Tropical Crops and Pastures, Australia.Google Scholar
Walker, D., Bird, A., Flora, T. & O'Sullivan, B. (1992). Some effects of feeding Tribulus terrestris, Ipomoea lonchophylla and the seed of Abelmoschus ficulneus on fetal development and the outcome of pregnancy in sheep. Reproduction, Fertility and Development 4, 135–144.CrossRefGoogle ScholarPubMed
Weston, E. J. & Moir, K. W. (1969). Grazing preferences of sheep and nutritive value of plant components in a Mitchell grass association in north-western Queensland. Queensland Journal of Agricultural and Animal Sciences 6, 639–650.Google Scholar