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17 results on '"Coles, Graeme D."'

1. An examination of the ability of plantain (Plantago lanceolata L.) to mitigate nitrogen leaching from pasture systems.

Author

Eady, Colin, Conner, Anthony J., Rowarth, Jacqueline S., Coles, Graeme D., Deighton, Matthew H., and Moot, Derrick J.

Subjects
NITROGEN excretion, PASTORAL systems, PASTURE management, PLANTAGO, URINATION
Abstract

Plantain (Plantago lanceolata L.) has recently been thrust into the limelight as a potential tool for mitigating nitrogen losses from the New Zealand pastoral environment. It is claimed to possess characteristics to reduce nitrogen leaching through both animal and soil-based mechanisms. This review examines the use of plantain in New Zealand pastures and the research that has led to these claims. The focus is on the evaluation of scientific evidence for the mechanisms through which plantain is proposed to reduce nitrate leaching, as well as the research on the implementation of plantain into pastoral farm systems. Plantain clearly increases the urination of grazing animals; a trait not unique to plantain. This review concludes that many research studies supporting the beneficial impact of plantain do not stand up against scientific scrutiny associated with methodology and interpretation of data. It is recommended more research should be undertaken on other pasture species and management tools, that may be more effective alternatives to plantain for nitrogen mitigation in pastures. [ABSTRACT FROM AUTHOR]

Published
2025
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2. Response to comments on 'An examination of the ability of plantain (Plantago lanceolata L.) to mitigate N leaching from pasture systems'.

Author

Eady, Colin, Conner, Anthony J., Rowarth, Jaqueline S., Coles, Graeme D., Deighton, Matthew H., and Moot, Derrick J.

Subjects
ROTATIONAL grazing, CROP yields, ITALIAN ryegrass, SOIL biology, MILK yield, RUMEN fermentation, RYEGRASSES, WHITE clover
Abstract

The document is a response to comments on a review of plantain's ability to mitigate nitrogen leaching from pasture systems. The authors appreciate the responses and aim to highlight exaggerated claims and limited research criteria regarding plantain's effectiveness. They discuss key points such as the inappropriate use of certain figures and the mechanisms by which plantain reduces nitrogen leaching. The authors hope for positive scientific discussions to advance understanding of plantain and other pasture species for environmental benefits. [Extracted from the article]

Published
2025
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3. An agroecological approach to preparation and use of a milk protein production baseline.

Author

Coles, Graeme D. and Rowarth, Jacqueline S.

Subjects
PROTEINS in animal nutrition, ANIMAL herds, MILK proteins, RANGE management, MILK yield, UREA
Abstract

Commercial dairy production occurs in a complex management environment, but increasingly, the dairy manager is expected to provide detailed reporting of productivity and environmental outcomes, for which conventional research methods double-blind crossover or case:control trials are inappropriate. This paper demonstrates the development of a milk protein production monitoring tool using a temporal (baseline) control in longitudinal, census-type investigations of modulation of system performance in response to factor change. It utilises farm-derived current and historical data, and contrasts seasonal responses with those achieved on neighbouring farms in a 2 × 2 contingency table. The approach is then shown to be useful in assessing the effect of two approaches to moderating milk urea concentration. Firstly, milk urea content can be monitored as it falls due to reduced feed protein content, and this fall can be arrested when milk protein content starts to decline relative to the value expected for the herd at any lactation stage. Secondly, by providing a dietary intervention aimed at increasing the availability of metabolic energy in the last month before calving, udder development can be augmented, leading to greater protein secretion capacity, meaning greater utilisation of circulating amino acids, and thus more limited substrate for urea synthesis. Thus, the changing impact of differing nutrition practices on dairy herd nitrogen excretion to environment can be followed with daily precision. In principle this approach can provide useful insights into a wide range of practical management interventions. [ABSTRACT FROM AUTHOR]

Published
2024
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6. Randomized controlled crossover study of the effect of a highly [beta]-glucan-enriched barley on cardiovascular disease risk factors in mildly hypercholesterolemic men

Author

Keogh, Geraldine F, Cooper, Garth JS, Mulvey, Tom B, McArdle, Brian H, Coles, Graeme D, Monro, John A, and Poppitt, Sally D

Subjects
Cardiovascular diseases -- Prevention, High-fiber diet -- Health aspects, Hyperlipidemia -- Diet therapy, Food/cooking/nutrition, Health
Abstract

Background: Soluble-fiber [beta]-glucan derived from oats can reduce cardiovascular disease (CVD) risk through reductions in total and LDL cholesterol. Barley-derived [beta]-glucan may also improve serum cholesterol, but large quantities are required for clinical significance. Objective: This trial investigated whether a [beta]-glucan-enriched form of barley can favorably modify cholesterol and other markers of CVD and diabetes risk. Design: Eighteen mildly hyperlipidemic ([bar]x [+ or -] SD: 4.0 [+ or -] 0.6 mmol LDL cholesterol/L) men with a mean ([+ or -] SD) body mass index (in kg/[m.sup.2]) of 27.4 [+ or -] 4.6 were randomly assigned in this single-blind, 2 x 4-wk trial to either the treatment arm [8.1-11.9 g [beta]-glucan/d (scaled to body weight)] or the control arm (isoenergetic dose of 6.5-9.2 g glucose/d). After a washout period of 4 wk, dietary regimens were crossed over. The trial took place in a long-stay metabolic facility, and all foods were provided (38% of energy from fat). Fasted blood samples were collected on days 0, 1, 7, 14, 21, 28, and 29 in both study arms. An oral-glucose-tolerance test was carried out on days 0 and 29. Results: There was no significant change ([DELTA]) in total ([DELTA] = -0.08 mmol/L, -1.3%), LDL ([DELTA] = -0.15 mmol/L, -3.8%), or HDL ([DELTA] = 0 mmol/L) cholesterol or in triacylglycerol ([DELTA] = 0.18 mmol/L), fasting glucose ([DELTA] = -0.05 mmol/L), or post-prandial glucose when analyzed between treatments (P > 0.05; ANOVA). Conclusion: The effect of [beta]-glucan-enriched barley on lipid profile was highly variable between subjects, and there was no evidence of a clinically significant improvement in CVD risk across this group of mildly hyperlipidemic men. KEY WORDS Serum cholesterol, soluble dietary fiber, [beta]-glucan, barley, randomized controlled trial, hyperlipidemic men

Published
2003

8. Food and nutritional security requires adequate protein as well as energy, delivered from whole-year crop production

Author

Coles, Graeme D, Wratten, Stephen D, Porter, John Roy, Coles, Graeme D, Wratten, Stephen D, and Porter, John Roy

Abstract

Human food security requires the production of sufficient quantities of both high-quality protein and dietary energy. In a series of case-studies from New Zealand, we show that while production of food ingredients from crops on arable land can meet human dietary energy requirements effectively, requirements for high-quality protein are met more efficiently by animal production from such land. We present a model that can be used to assess dietary energy and quality-corrected protein production from various crop and crop/animal production systems, and demonstrate its utility. We extend our analysis with an accompanying economic analysis of commercially-available, pre-prepared or simply-cooked foods that can be produced from our case-study crop and animal products. We calculate the per-person, per-day cost of both quality-corrected protein and dietary energy as provided in the processed foods. We conclude that mixed dairy/cropping systems provide the greatest quantity of high-quality protein per unit price to the consumer, have the highest food energy production and can support the dietary requirements of the highest number of people, when assessed as all-year-round production systems. Global food and nutritional security will largely be an outcome of national or regional agroeconomies addressing their own food needs. We hope that our model will be used for similar analyses of food production systems in other countries, agroecological zones and economies.

Published
2016

14. An Objective Dry Pea ‘Colour’ Scoring System for Commercial and Plant Breeding Applications

Author

Coles, Graeme D

Abstract

For human consumption, colour of dry peas is an important quality criterion, presently assessed subjectively. Samples which are dark and even in colour are preferred to those which are bleached and variable. The capacity of image analysis methods to provide an objective colour scoring system was investigated, and useful predictive relationships were found between subjective rankings for colour allotted to members of a large set of training samples, and ranking for median optical density, optical density proportional range and median seed size. Training samples were drawn at random from the pea sample population, and were not evenly distributed, so spacings between rankings were corrected by reference to the variance of the mean ranking for a sample. This correction allowed the predictive variables to explain 64% of the observed variation in the corrected rank. When the required precision of a derived scoring system was set to ±1·0 score points, it was found that the set of training samples could be covered by 6·95 score points, so a scoring calibration equation was developed in which increasing colour loss caused a higher score. The darkest sample in the training set was arbitrarily chosen to have a score of 5, to allow for the possibility of intrinsically darker, less bleached samples. This scoring system is at least twice as precise as the current subjective approach, and can be applied using any image analysis system that can be calibrated against cheap, highly consistent, photographic standard grey cards. The performance of the system may be improved further if chrominance variation can be taken into account. © 1997 SCI.

Published
1997
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17. The relationship between intra-sample variability and crop product quality

Author

Coles, Graeme D.

Subjects
quality, variability, image analysis, statistics, wheat, barley, peas, colour, flour yield, water absorption, water uptake, work, input, maltability, non-normality, REML, ANZSRC::070305 Crop and Pasture Improvement (Selection and Breeding), ANZSRC::070103 Agricultural Production Systems Simulation
Abstract

The observation that food technologists attempt to minimise seed character variation when using crop products to produce foodstuff stimulated the hypothesis that knowledge of the nature, properties and origins of intra-sample variation would aid prediction of crop product quality. The hypothesis was tested in 3 case studies. Pea seed colour variability was shown to be useful for predicting a pea colour acceptability score derived from ranking studies. In a second case study, wheat seed size variation was shown to have value for predicting flour yield in a number of cultivars. Knowledge of grain protein content improved predictability of flour yield. In one cultivar (Batten) subjected to a wide range of environmental stresses, seed size variability measures, in combination with grain protein content, predicted flour yield, flour water absorption and dough work input requirement as well as current laboratory procedures. Other quality characteristics were predicted well enough for quality segregation purposes. The sources of wheat seed size variability were examined in a head dissection experiment, and observed patterns found to be primarily under genetic control, with random variability restricted to the head-to-head component. A more elaborate experiment is proposed to allow the construction of a cultivar seed size variation "template" against which the random component can be determined more accurately. In the third case study, the relationship between maltability and water uptake variation in barley was investigated. Although a strong relationship between bulk water uptake and maltability was found, and a two-phase seed water uptake model was supported, derived variability statistics could not be used to give useful predictions of maltability. It is postulated that insufficient data were collected to allow the detection of all the double normal distributions that exist (as predicted by the two-phase water uptake model), and to derive reliable estimates of sub-distribution statistics. The results of this case study therefore neither support or refute the hypothesis. More detailed experiments are proposed to obtain more reliable variability estimates against which to compare maltability values. Overall, the data obtained give good support for the hypothesis, but expose the need to identify the fixed, genetically-determined components of variation, so that they can be separated from the random components likely to be the best predictors of environmental impact on quality.

Published
1998

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