The interrelationship of some components of forage quality

Thomson, A. J.; Rogers, H. H.

doi:10.1017/s002185960002565x

Cited by 9 publications

(4 citation statements)

References 9 publications

(7 reference statements)

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“…(1994) that selection for high WSC concentration has not been at the expense of CP concentration. The negative relationship between WSC and CP reported previously (Dent & Aldrich 1963; Thompson & Rogers 1971; Stewart et al . 2009) was suggested by Radojevic et al .…”

Section: Discussionmentioning

confidence: 48%

“…The similar results of these two studies support the conclusion of Radojevic et al (1994) that selection for high WSC concentration has not been at the expense of CP concentration. The negative relationship between WSC and CP reported previously (Dent & Aldrich 1963;Thompson & Rogers 1971;Stewart et al 2009) was suggested by Radojevic et al (1994) to be more likely a result of environmental, rather than genetic factors. While CP concentration did not vary between cultivars, lower fibre concentrations were measured in both the high sugar cultivars compared to the control.…”

Section: Resultsmentioning

confidence: 62%

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Longer defoliation interval ensures expression of the ‘high sugar’ trait in perennial ryegrass cultivars in cool temperate Tasmania, Australia

et al. 2014

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Perennial ryegrass (Lolium perenne L.) cultivars have been developed to express higher levels of leaf water-soluble carbohydrates (WSC), but expression of this 'high sugar' trait varies between environments and is likely to be further influenced by the extent of plant re-growth. The herbage WSC concentration and the ratio of WSC to crude protein (WSC : CP) in high sugar cultivars AberMagic and SF Joule were therefore compared with a control cultivar, Arrow, under cool temperate Tasmanian conditions and two defoliation interval treatments. The irrigated cultivars were subjected to defoliation at either the 1·5-leaf or 3-leaf stage of re-growth, and additional components of nutritive value (fibre concentrations and metabolizable energy content) and dry matter (DM) yields were measured throughout a 12-month period (March 2011 to March 2012). The high sugar trait was consistently expressed in AberMagic, which under both the 1·5-leaf and 3-leaf stages defoliation intervals, displayed the highest WSC concentration (mean 194 and 247 mg/g DM, respectively, compared with 153 and 178 mg/g DM for Arrow) and highest WSC : CP ratio (mean 0·74 and 1·29, respectively, compared with 0·58 and 0·85 for Arrow). Defoliation at the 3-leaf stage of regrowth ensured greater expression of the high sugar trait in both AberMagic and SF Joule, as measured by the increase in WSC concentration and WSC : CP ratio as a result of increasing defoliation interval. The strength and consistency of trait expression in AberMagic under the 3-leaf stage defoliation interval warrants further research to investigate its effect on rumen nitrogen (N) partitioning and milk production in this environment.

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Section: Discussionmentioning

confidence: 48%

Section: Resultsmentioning

confidence: 62%

Longer defoliation interval ensures expression of the ‘high sugar’ trait in perennial ryegrass cultivars in cool temperate Tasmania, Australia

et al. 2014

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“…It is commonly found that WSC and CP are strongly negatively related both in individual plants (Vose and Breese, 1964;Valentine and Charles, 1979;Bugge, 1978) and in swards (Dent and Aldrich, 1963;Thompson and Rogers, 1971 and Grimes et al, 1967). This would suggest a strict limit on the proportion of cell content to cell wall in plants.…”

Section: Discussionmentioning

confidence: 99%

“…Thus, WSC appears to play a key role in feeding value but is necessarily interrelated with other herbage quality components such as DMD and CP. Some of these relationships were investigated in detail in timothy by Thompson and Rogers (1971) and to some extent in perennial ryegrass by Dent and Aldrich (1963). Relationships between WSC content and herbage production are not well documented, although WSC is necessarily linked to growth as a store of energy and as an osmoticum promoting water uptake during cell, and hence leaf, expansion.…”

Section: Introductionmentioning

confidence: 99%

Water‐soluble carbohydrates in perennial ryegrass breeding

Humphreys

1989

Grass and Forage Science

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Perennial ryegrasses showing genetic differences in water-soluble carbohydrate content (WSC) were assessed for dry matter digestibility (DMD), crude protein (CP) and dry matter production (DM) in both spaced plant and small plot trials. Among 100 accessions grown as spaced plants there appeared to be more genetic variation for WSC than for DMD or CP. In both spaced plants and plots, WSC was consistently positively correlated with DMD, negatively correlated with CP and showed little correlation with DM. Correlations between CP and DMD were rather inconsistent and some negative correlations were obtained between CP and DM, suggesting that environmental effects, particularly with regard to nitrogen availability, affected CP more than WSC content. It was concluded that there is considerable potential for using ryegrasses with high WSC contents to develop varieties with improved feeding value without sacrificing production.

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Valuing forages for genetic selection: what traits should we focus on?

Chapman

Edwards

Stewart³

et al. 2015

Anim. Prod. Sci.

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Failure over the past two to three decades to implement industry-led, systematic forage evaluation systems that translate forage performance data to animal production and economics means that the livestock industries are poorly positioned to judge how much economic benefit they are gaining from forage plant improvement and to propose future priorities and targets. The present paper identifies several knowledge gaps that must be filled to enable the value being delivered to pasture-based livestock industries by forage improvement to be determined, demonstrated to farmers and increased in the future. Seasonal yield, total annual yield, nutritive value and feeding value of pasture are all important traits for driving the productivity of pasture-based livestock production systems. From a farm systems perspective, persistence of the yield or quality advantage of new cultivars is also economically important. However, this is the least well defined of the productivity traits considered in the paper. Contrary to anecdotal reports, evidence indicates that the genetic potential of modern ryegrass cultivars to survive in grazed pastures is at least equivalent to that of older cultivars. Plant breeding in Europe and New Zealand has changed the seasonal yield, quality and intake potential of perennial ryegrass. On the basis of dry matter (DM) yield data from small-plot evaluation trials, the New Zealand forage value index indicates that the top-ranked perennial ryegrass cultivars offer between NZ$280 and NZ $650/ha per year potential additional operating profit to dairy businesses (depending on region), compared with a historical genetic base of cultivars that were first entered into yield testing programs between 1991 and 1996. The equivalent figure in Ireland (including nutritive value effects) is about €325/ha per year. These estimates are yet to be confirmed in animal production studies. In intensive dairy systems, current rates of genetic gain in DM yield lag well behind realised rates of gain in animal genetics and associated increases in feed demand per animal. Genetic gains in yield need to double from current rates (estimated at 0.5% per year); but, it is not known whether this is possible in an outcrossing species such as perennial ryegrass, which is normally grown in a mixture with other species, especially white clover. Improvements in DM yield in seasons where extra DM has greatest economic value in grazing systems should dominate breeding objectives, but this must now be augmented by consideration of the environmental impacts of intensive pasture-based livestock production systems and opportunities to mitigate this through germplasm selection. There is less evidence that nutritive or feeding value of ryegrass cultivars significantly limits animal production and profitability and useful improvements have already been made using tetraploids and later heading material.

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The interrelationship of some components of forage quality

Cited by 9 publications

References 9 publications

Longer defoliation interval ensures expression of the ‘high sugar’ trait in perennial ryegrass cultivars in cool temperate Tasmania, Australia

Longer defoliation interval ensures expression of the ‘high sugar’ trait in perennial ryegrass cultivars in cool temperate Tasmania, Australia

Water‐soluble carbohydrates in perennial ryegrass breeding

Valuing forages for genetic selection: what traits should we focus on?

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