Variation within and between two saltbush species in plant composition and subsequent selection by sheep
Hayley C. Norman AC , Colby Freind B , David G. Masters A , Allan J. Rintoul A , Robyn A. Dynes A and Ian H. Williams B
A CSIRO Livestock Industries, Centre for Environment and Life Sciences, Private Bag 5, Wembley, WA 6913, Australia; and Cooperative Research Centre for Plant-based Management of Dryland Salinity, University of Western Australia, Crawley, WA 6009, Australia.
B School of Animal Biology, Faculty of Natural and Agricultural Sciences, University of Western Australia, Crawley, WA 6009, Australia.
Australian Journal of Agricultural Research 55(9) 999-1007 http://dx.doi.org/10.1071/AR04031
Submitted: 10 February 2004 Accepted: 4 August 2004 Published: 24 September 2004
This work examines nutritive value and preference by sheep of 2 saltbush species, river saltbush (Atriplex amnicola) and old man saltbush (Atriplex nummularia). Both species are woody perennials that are native to Australia and used in commercial grazing systems. The hypothesis for this study was that sheep will graze saltbushes with higher nutritive value and lower secondary compounds in preference to bushes with lower nutritive value and higher secondary compounds. This was expected to be found both within and between the old man and river saltbush species.
To test the hypothesis, 10-month-old Merino ewes grazed a 10-ha plot containing a mixture of old man and river saltbush in approximately equal proportions. Within the plot, and prior to grazing, 20 bushes of each species were pegged for identification and samples of edible plant material collected for analysis. Each week during the grazing period the bushes were photographed for assessment of preference. Sheep preferred river saltbush to old man saltbush and also showed some preferences for specific bushes within each species. Differences in digestibility of dry matter and organic matter, crude protein, ash, oxalates, and nitrates were not clearly associated with differences in preference. Although the reasons for preferences were not demonstrated, the analysis of the plant material did indicate that the content of total ash and oxalates was at levels likely to depress voluntary feed intake.
A non-destructive method for estimating the weight of forage on shrubs.
Australian Rangeland Journal
The implications of condensed tannins on the nutritive value of temperate forages fed to ruminants.
The British Journal of Nutrition
Sulfur metabolism and excretion studies in ruminants. 10. Sulphide toxicity in sheep.
Australian Journal of Biological Sciences
Osmoregulation in halophytic higher plants: a comparative study of soluble carbohydrates, polyols, betaines and free proline.
Plant, Cell and Environment
Role of toxins in intake of varied diets by sheep.
Journal of Chemical Ecology
Fine-scale discrimination of forage quality by sheep offered a soybean meal or barley supplement while grazing a N-fertilized heather (Calluna vulgaris) mosaic.
Journal of Agricultural Science (Cambridge)
‘Methods for the analysis of feeds eaten by ruminants.’
CSIRO PublishingMelbourne, Vic.
Minimal total discomfort as a concept for the control of food intake and selection.
CSIRO PublishingCollingwood, Vic.
Utilization of halophytes by livestock on rangelands. Problems and prospects.
‘Halophytes as a resource for livestock and for rehabilitation of degraded land’.
Kluwer Academic PublishersDordrecht, The Netherlands
Quantitative determination of calcium oxalate and oxalate in developing seed of soybean (Leguminosae).
American Journal of Botany
Composition of the fractions of dry, mature subterranean clover digested in vivo and in vitro.
‘Proceedings of the XVII International Grasslands Congress’.
New Zealand Grasslands AssociationPalmerston North, NZ
Diet selection in sheep: the ability of growing lambs to select a diet that meets their crude protein (N × 6.25) requirements.
The British Journal of Nutrition
Mild conditioned food aversions developed by sheep towards flavours associated with plant secondary compounds.
Journal of Chemical Ecology
Forage value and utilisation of chenopod dominated shrubland.
Reclamation and Revegetation Research
The DMACA-HCl protocol and the threshold proanthocyanidin content for bloat safety in forage legumes.
Journal of the Science of Food and Agriculture
Opportunities and limitations for animal production from saline land.
Asian-Australasian Journal of Animal Science
Digestion of environmental materials for analysis by Inductively Coupled Plasma-Atomic Emission Spectrometry.
Grazing a saltbush (Atriplex-Maireana) stand by Merino wethers to fill the ‘autumn feed-gap’ experienced in the Western Australian wheat belt.
Australian Journal of Experimental Agriculture
National Land and Water Resources Audit
‘Australian Dryland Salinity Assessment 2000.’
National Land and Water Resources AuditCanberra, ACT
Utilization of saltbush as feed for sheep.
Honours thesis, University of Western Australia, Perth.
The raison d'être of secondary plant chemicals?
Trends in Plant Science
Post ingestive feedback as an elementary determinant of food preference and intake in ruminants.
Journal of Range Management
Roles of odor, taste, and toxicity in the food preferences of lambs: implications for mimicry in plants.
Influence of plant toxins on food ingestion by herbivores.
‘Recent advances on the nutrition of herbivores’.
Malaysian Society of Animal ProductionKuala Lumpur
The influence of oral administration of non-protein N feeding compounds upon blood ammonia and urea levels in lambs.
Journal of Animal Science
‘Forage shrubs and grasses for revegetating saltland.’
Department of AgricultureWestern Australia
Standing Committee on Agriculture
‘Feeding standards for Australian livestock.’
CSIRO PublicationsEast Melbourne, Vic.
Taxonomic and ecological aspects of the distribution of glycinebetaine and related compounds in plants.
Body condition scoring of sheep and goats.
Department of Agriculture, Western Australia.
Comparison of LECO FP-228 ‘N Determinator’ with AOAC copper catalyst Kjeldahl method for crude protein.
Journal – Association of Official Analytical Chemists
Sheep and saltbush — are they compatible?
‘Productive Use and Rehabilitation of Saline Lands, 3rd National Conference’.
Echuca, VicPromaco Conventions Pty Ltd
The tolerance of sheep to sodium chloride in food or drinking water.
Australian Journal of Agricultural Research
Photometric determination of chlorides in water.