Ecology of the Mediterranean Annual-Type Pasture

Rossiter, RC

doi:10.1016/s0065-2113(08)60647-1

Cited by 187 publications

(90 citation statements)

References 159 publications

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“…Changes in optimal management need to be accounted for when calculating how the profitability of a farm is influenced by changing traits of animals (Groen, 1989;Amer, 1994). In areas where sheep are produced in Western Australia, there are big differences between regions in the amount and variation of pasture growth within and between years (Rossiter, 1966;Schut et al, 2010). These differences between regions in pasture growth can affect the optimal management of livestock (Chapman et al, 2009;Young et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Breeding objectives for sheep should be customised depending on variation in pasture growth across years

Rose

Mulder

Thompson

et al. 2015

Animal

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Breeding programmes for livestock require economic weights for traits that reflect the most profitable animal in a given production system, which affect the response in each trait after selection. The profitability of sheep production systems is affected by changes in pasture growth as well as grain, meat and wool prices between seasons and across years. Annual pasture growth varies between regions within Australia's Mediterranean climate zone from low growth with long periods of drought to high growth with shorter periods of drought. Therefore, the objective of this study was to assess whether breeding objectives need to be adapted for regions, depending on how reliable the pasture growth is across years. We modelled farms with Merino sheep bred for wool and meat in 10 regions in Western Australia. Across these 10 regions, mean annual pasture growth decreased, and the CV of annual pasture growth increased as pasture growth for regions became less reliable. We calculated economic values for nine traits, optimising management across 11 years, including variation for pasture growth and wool, meat and grain prices between and within years from 2002 to 2012. These economic values were used to calculate responses to selection for each trait for the 10 regions. We identified two potential breeding objectives, one for regions with low or high reliability and the other for regions with medium reliability of pasture growth. Breeding objectives for high or low pasture growth reliability had more emphasis on live weight traits and number of lambs weaned. Breeding objectives for medium reliability of pasture growth had more emphasis on decreasing fibre diameter. Relative economic weights for fleece weight did not change across the regions. Regions with low or high pasture reliability had similar breeding objectives and response to selection, because the relationship between the economic values and CV of pasture growth were not linear for live weight traits and the number of lambs weaned. This non-linearity was caused by differences in distribution of pasture growth between regions, particularly during summer and autumn, when ewes were pregnant, with increases in energy requirements affecting the value of lambs weaned. In addition, increasing live weight increased the intake capacity of sheep, which meant that more poor quality pasture could be consumed during summer and autumn, which had more value in regions with low and high pasture reliability. We concluded that breeding values for sheep production systems should be customised depending on the reliability of pasture growth between years.

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Section: Introductionmentioning

confidence: 99%

Breeding objectives for sheep should be customised depending on variation in pasture growth across years

Rose

Mulder

Thompson

et al. 2015

Animal

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“…These systems are characterised by large fluctuations in the quantity and quality of pasture available between and within years (Rossiter 1966;Purser and Southey 1984;Thompson et al 1994). Therefore, achieving the appropriate balance between stocking rate, ewe production and levels of supplementary feeding is a major challenge for these systems.…”

Section: Introductionmentioning

confidence: 99%

Whole-farm profit and the optimum maternal liveweight profile of Merino ewe flocks lambing in winter and spring are influenced by the effects of ewe nutrition on the progeny's survival and lifetime wool production

Young

Thompson

Curnow³

et al. 2011

Anim. Prod. Sci.

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Abstract. Profitability of sheep production systems in southern Australia is optimised at a stocking rate that provides adequate nutrition for breeding ewes and enables efficient utilisation of grown pasture and supplements. In this paper we used bio-economic modelling to develop optimum liveweight 1 profiles for spring-lambing Merino ewes in different environments. The modelling included the impacts of the ewe liveweight profile on the production of the ewe and the survival and lifetime wool production of her progeny. Fifteen ewe liveweight profiles were analysed for each region to determine the profitability of varying ewe liveweight at joining, varying rate of loss of liveweight after joining and the rate of gain in liveweight from the minimum to lambing. The analyses support the hypotheses that whole-farm profitability is sensitive to the liveweight profile of Merino ewe flocks and that there is a liveweight profile that maximises whole-farm profit. The variation between the most and least profitable ewe liveweight profile was

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“…In these pastures, both the grass and legume components germinate with the opening rains in autumn. At the end of the growing season in late spring-early summer, both components flower, set seed and die, and the livestock depend on dry feed during the summer supplemented by the high protein of the subterranean clover seed, which the livestock (particularly sheep) can access from on or just below the soil surface (Rossiter 1966). When landscapes depend on annual grasses as well annual legumes, they are prone to the development of soil acidity, and a more sustainable system is to combine introduced perennial grasses with the annual legumes (Williams 1980;Blair 1997;FitzGerald and Lodge 1997).…”

Section: High-rainfall Temperate Southmentioning

confidence: 99%

Use of functional traits to identify Australian forage grasses, legumes and shrubs for domestication and use in pastoral areas under a changing climate

Mitchell¹,

Norman

Whalley

2015

Crop Pasture Sci.

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Abstract. Considerable uncertainty exists about future climatic predictions but there is little doubt among experts that the future will be warmer. Climate change and the associated elevation in atmospheric CO 2 level and temperatures will provide novel challenges and potential opportunities for cultivated plant species. Plant breeding and domestication can contribute to improvements in both yield and quality of native grasses, legumes and forage shrubs. This review explores the use of functional traits to identify native Australian grasses, legumes and forage shrubs suitable for domestication, to meet the challenges and opportunities under a changing climate in pastoral areas in Australia. The potential of these species in terms of life history, regenerative traits, forage quality and quantity, drought tolerance and invasiveness is examined. The paper focuses on three Australian pastoral regions (high-rainfall temperate south, tropical and subtropical grasslands, low-rainfall semi-arid shrublands), in terms of future climate predictions and potential of selected native species to meet these requirements. Selection for adaptation to new climatic environments is challenging but many native species already possess the traits required to cope with the environment under future climate scenarios.

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Ecology of the Mediterranean Annual-Type Pasture

Cited by 187 publications

References 159 publications

Breeding objectives for sheep should be customised depending on variation in pasture growth across years

Breeding objectives for sheep should be customised depending on variation in pasture growth across years

Whole-farm profit and the optimum maternal liveweight profile of Merino ewe flocks lambing in winter and spring are influenced by the effects of ewe nutrition on the progeny's survival and lifetime wool production

Use of functional traits to identify Australian forage grasses, legumes and shrubs for domestication and use in pastoral areas under a changing climate

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