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- By Sherese Ali, Danielle Molinari Andrade, Elinor Ben-Menachem, Weerawadee Chandranipapongse, Pamela Crawford, Anne Davis, Carin Dove, Nancy Foldvary-Schaefer, Elizabeth E. Gerard, Cristina Y. Go, Cynthia L. Harden, Dini Hui, Shinya Ito, Jaromir Janousek, Nathalie Jette, Pavel Klein, A. Gabriela Lizama, Kristi A. McIntosh, Georgia Montouris, Brian J. Murray, Ori Nevo, Eugene Ng, Alison M. Pack, Sima Indubhai Patel, Page B. Pennell, Kalliopi A. Petropoulou, Mark Quigg, Alessandra Scaparrotta, Marianna Sebastiani, Patricia Osborne Shafer, O. Carter Snead, Diane T. Sundstrom, Alberto Verrotti, Carla Verrotti, Jonathan H. Waters, Fatima Zahir
- Edited by Esther Bui, Autumn M. Klein
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- Women with Epilepsy
- Published online:
- 05 August 2014
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- 31 July 2014, pp vii-x
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The influence of herbage mass and supplementary feeding on nutrient flows and animal performance in grazing, lactating ewes
- H. DOVE, J. A. MILNE, C. S. LAMB, A. M. SIBBALD, H. A. McCORMACK
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- Journal:
- The Journal of Agricultural Science / Volume 150 / Issue 5 / October 2012
- Published online by Cambridge University Press:
- 15 March 2012, pp. 644-662
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The present paper examines the effect of the type of supplement given to grazing ewes in early lactation on the performance of ewes and lambs on temperate sown pastures. Lactating ewes grazed perennial ryegrass pastures at either low- or high-herbage masses, between days 8 and 96 of lactation. On the low-herbage mass treatments, ewes were either unsupplemented or received either an energy supplement (sugarbeet pulp) or a protein supplement (1:1 sugarbeet pulp:formaldehyde-treated soyabean meal) between days 8 and 50 of lactation. The provision of supplements or the higher herbage mass led to increases in live weight (LW) and body condition score of ewes during days 8–50 of lactation, while unsupplemented ewes on the low-herbage mass treatment lost LW and had lower body condition scores. After supplementation finished, previously supplemented ewes or those grazing the higher herbage mass lost LW and condition, while unsupplemented ewes grazing the low-herbage mass gained both LW and condition. Non-treatment factors such as ewe dentition score significantly affected ewe and lamb LW gains. Regression analyses indicated that lamb LW gains between days 8 and 50 of lactation were 40–60 g/d greater in lambs from supplemented ewes or ewes grazing the higher herbage mass cf. unsupplemented ewes. Overall, there was no difference in the response of ewes or lambs to the type of supplement. Milk yields were estimated in a subset of ewes (replicate 4). Ewes on the high-herbage mass treatment or those supplemented with protein had higher milk yields than those on the low-herbage mass treatment or those given the energy supplement. Supplemented ewes in this replicate had higher metabolizable energy intakes (MEIs). Measurements of digesta flow in a further subset of ewes indicated that both supplements resulted in greater ruminal and post-ruminal supplies of energy and protein than in the unsupplemented ewes at the lower herbage mass, but differences in ruminal and post-ruminal nutrient provision between the supplements were less than had been intended. It is suggested that this is the reason for there being no statistical difference in the performance of ewes and lambs in response to the type of supplement.
Effects of a concentrate supplement on the intake and digestion of a low-quality forage by lambs
- P. T. Doyle, H. Dove, M. Freer, F. J. Hart, R. M. Dixon, A. R. Egan
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- Journal:
- The Journal of Agricultural Science / Volume 111 / Issue 3 / December 1988
- Published online by Cambridge University Press:
- 27 March 2009, pp. 503-511
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Weaned lambs of mean weight 25 kg were offered a diet of mature oaten hay or hay supplemented with a pelleted mixture of oat grain and sunflower meal (2:1), at one of three rates, for 86 days. The effect of the supplement on the voluntary intake of hay was measured during the first 20 days when feed was offered twice daily (Expt 1), after which the effects on ruminal and post-ruminal digestion were investigated under continuous feeding conditions (Expt 2).
In Expt 1 the first increment of supplement increased the total intake of organic matter (OM) but increasing the supplement further, up to 510 g D.M., had no additional effect. The voluntary intake of oaten hay was not significantly reduced by the lowest rate of supplementation but at higher rates was depressed at a mean rate of 92 g/100 g supplement. Rates of change in fasted weight on the four treatments were —63, —5, 21 and 45 g/day, respectively.
In Expt 2, where the rates of hay intake were held at 85% of those achieved in Expt 1, the first increment of supplement increased the pool size of OM and cell wall components in the reticulorumen by about 50%. It also increased their outflow rates at the abomasum by 24% and 33%, respectively, but significantly decreased the fractional outflow rate and fractional digestion rate of cell wall components. Supplementation decreased the proportion of apparent OM digestion that occurred in the reticulo-rumen from 76% to 65%. The presence of supplement doubled the ammonia pool in the rumen and increased the abomasal flow on non-ammonia nitrogen (NAN) and microbial NAN by 70%. Estimates of the amounts of crude protein apparently digested in the intestines (DCPi) increased linearly with proportion of supplement in the diet. However, the apparent digestibility of the hay was decreased, rather than increased, by the supplement. Although higher rates of supplement did not significantly change the elevated rumen pools of OM and cell wall components, there was a consistent tendency for these to decrease.
The results are consistent with the view that the intake of unsupplemented hay was limited by its low nitrogen content and the intake of supplemented hay may have been limited primarily by the capacity of the reticulo-rumen, although other factors were increasingly involved at higher rates of supplementation.
Responses to supplements by weaned lambs when grazing mature pasture or eating hay cut from the same pasture
- M. Freer, H. Dove, A. Axelsen, J. R. Donnelly
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- Journal:
- The Journal of Agricultural Science / Volume 110 / Issue 3 / June 1988
- Published online by Cambridge University Press:
- 27 March 2009, pp. 661-667
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Weaned cross-bred lambs either grazed mature pasture or were confined to yards where they were offered material cut from ungrazed areas of the same pasture. A 1:2 mixture (on an air-dry basis) of sunflower meal and oat grain was offered for 81 days at 0, 200, 400 or 600 g/head or ad libitum. Individual estimates of intake of pasture and supplement by grazing sheep at four levels of supplementation were made on four adjacent plots.
Weight gain increased from –30 to 178 g/day in the grazing animals as supplement intake increased up to 1030 g D.M./day and from –25 to 142 g/day in the yarded animals as supplement intake increased to 1076 g D.M./day. Growth of greasy wool increased from 4·5 to 11·7 g/day for grazing animals and from 4·5 to 10·2 g/day for those kept in yards.
At levels of supplement intake below 400 g D.M./day, the intake of grazed pasture increased by up to 58% compared with unsupplemented animals. However, when the intake of supplement was increased to about 650 g D.M./day, pasture intake fell, with an estimated substitution rate of 1·1 g D.M. pasture per g D.M. supplement. At all levels of supplementation, the intake of hay by the yarded lambs was less than half the intake of herbage in the field. However, at levels of supplement intake between 300 and 500 g D.M./day, the substitution rate was similar to that measured in the grazing animals, suggesting that this is an attribute of roughage quality, rather than differential eating behaviour between grazing and yarded animals.
The wastage, w (g D.M./day), of supplement was linearly related to the amount offered, s (g D.M./day), by the equation
w = 0·263s − 38·8; R2 = 0·89
Variability in supplement intake between individual grazing lambs was not affected by the level of supplementation but the coefficient of variation of supplement intake was considerably greater than that of the intake of unsupplemented pasture. Variability in the intake of pasture increased with the level of supplementation but variability in the total intake of food was similar at each level of supplement, indicating some degree of individual compensation in the intake of the two components.
Using the alkanes and long-chain alcohols of plant cuticular wax to estimate diet composition and the intakes of mixed forages in sheep consuming a known amount of alkane-labelled supplement
- H. Dove, E. Charmley
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In a feeding trial with 24 sheep, we used the alkanes, long-chain alcohols (LCOH) or both of these plant wax markers, to estimate the diet composition of animals offered diets comprising alkane-labelled cottonseed meal (CSM) together with up to four forages. The diets used were: Diet 1 subterranean clover (Trifolium subterraneum); Diet 2 subterranean clover + phalaris (Phalaris aquatica); Diet 3 subterranean clover, phalaris + annual ryegrass (Lolium rigidum); and Diet 4 subterranean clover, phalaris, annual ryegrass + wheat straw (Triticum aestivum). Estimates of diet composition were made following correction of faecal alkane or LCOH concentrations for incomplete faecal recovery, using recovery estimates derived from individual animals, mean recoveries for a given dietary treatment or grand mean recoveries. Estimated dietary proportions of CSM and known intakes of CSM were used to estimate forage intake. The LCOH concentrations of the diet components were much higher than their alkane concentrations, especially for phalaris. Multivariate analyses showed that the discriminatory information provided by the LCOH was additional to that provided by the alkanes, and that a combination of (LCOH + alkanes) discriminated better between diet components than either class of marker alone. Faecal recoveries of LCOH increased with increasing carbon-chain length; there were no differences in recovery attributable to diet. The most accurate estimates of diet composition were obtained with the combination of (LCOH + alkanes). Estimates of diet composition based on LCOH alone were not as good as alkanes alone, due to the high correlation between the LCOH profiles of phalaris and ryegrass. Total grass content of the diet was very accurately estimated using LCOH. Diet composition estimates provided estimates of whole-diet digestibility, which did not differ from the measured values. Trends in the accuracy of forage intake estimates reflected those found with diet composition and almost two-thirds of estimates based on (LCOH + alkanes) had lower error than those found with alkanes alone. The results confirm that supplements labelled with plant wax components can be used to estimate forage intake, and also show that the LCOH are useful markers for estimating diet composition. Intakes were also computed using a combination of natural LCOH concentrations in the diet and the daily dose rate of even-chain alkanes administered by intra-ruminal device. Differences between intakes so estimated and the measured intakes were closely related to the difference in faecal recovery between the LCOH/alkane pair used to estimate intake, by an amount close to that expected on theoretical grounds. It is concluded that the use of plant wax LCOH, especially in combination with alkanes, will result in improved estimates of diet composition and intake in grazing animals.
Faecal alkane recoveries from multi-component diets and effects on estimates of diet composition in sheep
- C. Elwert, H. Dove, M. Rodehutscord
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In a feeding trial with sheep, four animals each were fed one of the three roughages (perennial ryegrass (PR), meadow fescue (MF) and red clover (RC)) or one of the four different mixtures (g/day 250 : 250 : 250, 375 : 75 : 300, 525 : 187.5 : 37.5 and 75 : 525 : 150, respectively) of those three roughages, both with and without the inclusion of 100 g of beeswax-labelled barley. Further, four sheep received a pure lucerne diet to enlarge available data on single species faecal recoveries. All sheep except those fed single-component diets and the 250 : 250 : 250 roughage mix were administered intra-ruminal alkane controlled-release devices (CRD). The aim of the study was to investigate the effect of diet composition on faecal alkane recoveries, and to assess the accuracy of the alkane-based estimate of diet composition and intake based either upon a general set of faecal recoveries across diets or upon dietary recoveries and dietary samples more specifically attributable to individual dietary treatments. For each roughage component independently, the accuracy of diet composition estimates was assessed using linear regression across all diets. The estimates of the proportion of barley were analysed further using mean differences and mean prediction errors. Faecal alkane recovery increased with increasing chain length and was affected by diet composition. RC had a significantly higher faecal recovery for alkanes C25, C27, C29 and C31 than at least one of the other single-roughage diets. When considering mixed diets consisting of PR, MF, RC and barley, the composition of the roughage component significantly affected faecal recovery of all alkanes except C30 and C33. The inclusion of beeswax-labelled barley caused a decrease in faecal recovery of alkanes up to C29. This effect was attributable to the beeswax rather than the barley itself. By contrast, the decrease of faecal recovery of synthetic dosed alkanes from the CRD in diets containing barley, compared with the corresponding diets without barley, was attributable to the supplement itself. It was concluded that synthetic dosed alkanes behaved differently during gut transit from natural alkanes. The proportions of individual dietary components were estimated well over a wide range of proportions. Generally, the more information available, the more accurate the estimates achieved. However, a general set of faecal alkane recoveries and bulked samples of dietary components yielded estimates of diet composition sufficiently accurate for a large number of studies, especially in situations where groups of animals are of concern and not the individual animal.
The possible use of the alkenes (unsaturated hydrocarbons) of plant cuticular wax as diet composition markers in sheep
- H. Dove, M. Oliván
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- Journal:
- BSAP Occasional Publication / Volume 34 / 2006
- Published online by Cambridge University Press:
- 27 February 2018, pp. 1-7
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- 2006
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The objective of the current study was to investigate the possible use of alkenes (unsaturated hydrocarbons) of plant waxes as diet composition markers in sheep. Twenty-four sheep (30 kg live weight) were housed in individual pens (n=16, “pen” sheep) or in metabolism crates (n=8, “crate” sheep) for the total collection of faeces. Once daily, sheep were fed 720 g DM of a two-component diet consisting of a roughage source (chaffed perennial ryegrass) and a high-quality supplement (unpelleted sunflower meal, SFM) in different proportions, 7:1, 6:2, 5:3 and 4:4 (4 pen sheep and 2 crate sheep/treatment). SFM was labelled with a solution of beeswax to provide an alkane/ alkene profile different from the chaff. Diet composition was estimated from C27, C29, C31 and C33 alkene concentrations in diet and faeces (total faeces or rectal grab samples), using the least-squares package ‘EatWhat’. Estimates were conducted with or without correction of faecal alkane concentrations for incomplete faecal recovery, calculated from the alkene intakes and faecal outputs in the crate sheep.
Although the faecal alkene recoveries of alkenes were low, they did not differ between chain lengths for alkenes C27 to C33. Therefore in cage sheep, alkene-based estimates of SFM proportions, with or without faecal recovery correction, did not differ significantly from the proportions fed and were as accurate as earlier alkane-based estimates. In pen sheep, SFM proportions estimated from rectal grab samples were slightly but significantly over-estimated, regardless of whether or not recovery corrections were used. The over-estimates were not related to recovery corrections but to the small differences in concentrations between rectal grab samples from pen sheep and the total faeces from cage sheep. The lack of effect of recovery corrections does not mean they should be excluded from such calculations, as there may be situations in which there is an effect of carbon-chain length on alkene recovery. Use of recovery corrections also permits an estimate of whole-diet digestibility.
The present results indicate that alkenes could be useful additional markers to the alkanes for estimating the proportion of two dietary components in diets offered to sheep.
The use of n–alkanes and other plant–wax compounds as markers for studying the feeding and nutrition of large mammalian herbivores
- R.W. Mayes, H. Dove
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- Journal:
- BSAP Occasional Publication / Volume 34 / 2006
- Published online by Cambridge University Press:
- 27 February 2018, pp. 153-182
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- 2006
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In the study of the feeding behaviour and nutrition of free-ranging mammalian herbivores, determining what the animals are eating, its quality and quantity can be difficult to accomplish. The measurement processes themselves may disturb the animals’ normal foraging behaviours which can be a major problem in rangeland, forest and other semi-natural environments. Furthermore, animals are likely to select mixtures of plants and their components which differ from the available vegetation. Quantitative measures of diet composition, digestibility, faecal output and intake in individual grazing or browsing animals have depended on the use of faecal markers. These are materials measurable in faeces that originate from the diet (internal markers), or are absent from the diet, but administered by oral dosing (external markers). The ‘ideal’ faecal marker needs complete recovery in faeces, simple and accurate quantitative measurement, inertness in having no effect on the animal or its diet, and similar physical characteristics (in terms of particle size and density) to the digestive tract contents. No individual material or chemical entity has been found which fulfils all of the ‘ideal’ marker attributes. For example, lignin, indigestible acid-detergent fibre (IADF) and ‘chromogen’, have been used as internal markers, but since they are not discrete compounds, analytical methods are empirical., resulting in inconsistent faecal recoveries.
Virtually all higher plants have an outer surface layer of wax, which is usually a complex mixture of aliphatic lipid compounds whose composition differs between plant types, and different parts of the same plant. Plant waxes can be analysed as discrete compounds, are relatively inert, and because the patterns of individual compounds tend to differ between plant species, they offer the potential of enabling measurement of the contributions of specific plant species to the diet. Leaves and floral parts tend to have the highest concentrations; roots have very low levels. The main classes of plant waxes are straight and branched chain alkanes, alkenes, long–chain fatty acids and esters, long–chain fatty alcohols; long–chain fatty aldehydes and ketones and b–diketones. Analysis is usually carried out by a stepwise process of solvent extraction, purification and gas chromatography (GC). Straight–chain alkanes (n–alkanes) have been the most commonly used marker to date, being present as mixtures with chain lengths ranging from 21 to 37 carbon atoms. Over 90% of n–alkanes have odd–numbered carbon chains, with C29, C31 and C33 alkanes being dominant in most pasture species. Recovery in faeces of plant waxes is high but not complete, and is related to chain length, the longer the chain, the higher the recovery. Correction factors have been measured in a number of herbivore species.
The first application of plant-wax n-alkanes as faecal markers was to determine herbage digestibility in ruminants. Subsequently it was realised that dosed synthetic alkanes could be used to determine faecal output, and hence dosed and herbage alkanes could be concurrently used to estimate intake. This offered substantial advantages over other methods. Furthermore, differences between plant species and parts in their patterns of individual alkanes can be exploited to enable quantitative determination of diet composition from the patterns found in faeces. Since differences in the relative faecal recoveries of individual markers could modify the faecal marker pattern, recovery corrections may be necessary. This approach was first used for measuring the composition of simple dietary mixtures and the intake of dietary supplements to be determined. The use of long-chain fatty alcohols and fatty acids as additional markers offers the potential for more complex diets to be evaluated. The fact that plant-wax alkanes remain attached to particulate dietary residues throughout the ruminant gut, means that they are also good markers for determining the rate of passage of material along the digestive tract
Estimates of digestibility and faecal output obtained from respective natural and dosed n-alkanes will be biased, unless corrections are made to account for incomplete faecal recoveries. However, intake estimates will be unbiased if the faecal recoveries of the two markers are the same. Studies in sheep, cattle and goats have shown plant C33 and dosed C32 alkanes to have very similar faecal recoveries and thus give unbiased estimates of herbage intake. The alkane method for estimating intake offers advantages over other techniques. It gives individual-animal intakes and can be used where animals are receiving feed supplements. Also, GC analysis allows both plant and dosed markers to be determined at the same time, which limits analytical time, error and bias. Since the ratio of the concentrations in faeces is used, it is not necessary to obtain absolute faecal concentrations.
Alkenes and branched-chain alkanes have been investigated as additional markers for diet composition estimation since they can be quantified in the same GC analysis as n-alkanes. Although alkenes, which tend to be associated with floral plant parts, have low recoveries (25-40%), they can be useful diet composition markers since their recoveries are little affected by chain length. Faecal recoveries of the branched-chain alkanes, from Agrostis capillaris herbage, were slightly lower (60-65%) than the respective n-alkanes (C30 and C32) of equivalent carbon number (85-90%). These alkanes are rare in forage species, and their practical usefulness as markers for quantitative composition estimation has yet to be tested.
Long-chain fatty alcohols have been shown to be effective diet composition markers. In most plants fatty alcohol concentrations are higher than those of hydrocarbons, and there can be profound differences in composition between species. They may be of particular value for diets containing plants with low alkane concentrations. Faecal recoveries in sheep, like n-alkanes, increase progressively with chain length from about 60% to 90%. It has been shown experimentally that the use of alcohols, together with n-alkanes, is likely to give a better estimate of diet composition in a given situation than n-alkanes alone.
The very long-chain fatty acids of plant cuticular wax (C20-C34), originally suggested as digestibility markers, may also have potential as diet composition markers. Like n-alkanes and long-chain fatty alcohols, the faecal recoveries of plant-wax fatty acids in sheep increase with carbon chain length. Comparisons with n-alkanes and fatty alcohols suggested that the fatty acids were inferior as diet composition markers. This may have been due to the fact that the fatty acid extracts analysed by GC were relatively impure, containing a number of unidentified compounds. The reliability of plant-wax fatty acids as markers may be improved with more effective analytical procedures.
There are a number of ways of calculating the diet composition from marker patterns in the faeces and potential dietary components. A simple approach is to determine a solution from a matrix of simultaneous equations; the number of dietary components must equal the number of markers used. Because, for simple dietary mixtures, there may be more available markers than dietary components, difficulties may arise in making the best choice of marker. Least-squares optimisation methods allow the number of markers to exceed the number of diet components, and thus (in theory) make better use of available information.
Since the concept of using faecal marker patterns for making quantitative diet composition estimates is relatively new, the associated mathematical and statistical procedures used to date have been rather crude and simplistic. There is potential to make more effective use of the marker data by using more sophisticated computational approaches. These include a range of multivariate techniques, including: a) Principal component and discriminant analysis; b) The weighting of the contribution of different markers, since with the leastsquares optimisation procedure, markers with the highest overall concentrations contribute most to the composition estimate, even though some markers with low concentrations may have large relative differences between dietary components. It would logical to weight markers in favour of those having the greatest relative variation across dietary components, and those providing the least compositional information could be weighted against; c) Statistical procedures are needed to evaluate the quality of diet composition estimates. The minimisation procedures described earlier take no account of any within-component variation in marker composition, and the effect of such variation on the quality of resultant diet composition estimate is not known. Attempts are being made to develop statistical procedures which will provide details of confidence intervals of compositional estimates resulting from particular plant species mixtures of known within- and between-species variability in marker composition.
For reliable estimation of digestibility, intake and diet composition, the feed sample must be representative, with respect to its plant wax marker concentration, of the material ingested by the animals under investigation, not necessarily all of the material present. Since marker concentrations can differ for different plant parts and plant species, care must be taken in sampling the vegetation for analysis. Although oesophageal-fistulated animals have been used to collect samples of ingested vegetation, hand-plucked grass samples have been found to be adequate for uniform grass swards,. In heterogeneous vegetation environments, especially when browse species are present, herbivores are likely to be highly selective. It is thus wise to make preliminary observations of animals’ ingestive behaviours, so appropriate parts of the dietary plants are sampled.
The use of plant waxes, initially with alkanes, as markers in the study of the diets of domestic ruminants is finding increasing use in other herbivores, both domesticated and wild (moose, fallow deer, mountain hares, pigs, rabbits, horses, donkeys, giraffes). Such methodologies have been applied in non-mammalian herbivores, including birds (pigeons, and ostriches) and reptiles (tortoises). Synthetic alkanes have been used as markers to estimate digestibility and intake in fish. Although tests have not yet been carried out, plant wax marker methods may even be applicable to non-vertebrate herbivores, such as caterpillars, slugs and snails. Expansion of the technique to include plant wax compounds other than alkanes will broaden the spectrum of animals and systems which can and could be studied. Alkanes can be used to estimate the botanical composition of plant mixtures, including mixed root mats, and since these compounds can remain in soil for a considerable period, they may also be used to describe the vegetation history of an area by analysis of soil strata. There may be potential for this approach to be extended into archaeological and forensic studies. Insects and spiders contain hydrocarbons (mainly branched-chain alkanes) in their cuticular wax, and preliminary tests have indicated that these compounds are recoverable in the faeces of bats and insect-eating birds; thus they could be used to determine the insect species composition of the diets of insectivores. Analysis of these waxes is relatively simple, and although good GC equipment is required, there is scope for laboratories which do not posses the equipment to make the initial extractions and purification (simple but laborious), with the final GC analysis undertaken by a collaborating laboratory. Thus there are many uses of plant and animal waxes as markers, and potential applications are probably limited only by our imagination.
Estimation of roughage intake in sheep using a known daily intake of a labelled supplement
- C. Elwert, H. Dove
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- Journal:
- Animal Science / Volume 81 / Issue 1 / August 2005
- Published online by Cambridge University Press:
- 09 March 2007, pp. 47-56
- Print publication:
- August 2005
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A feeding trial with growing sheep was conducted on mixed roughage-supplement diets, to test whether roughage intake could be estimated from a known intake of a supplement and an alkane-based estimate of the supplement and roughage proportions in the diet (diet composition) without the need for separate dosing with external marker alkanes. Diets consisted of chaffed Trifolium subterraneum hay (SC), or a mix of SC and beeswax-labelled cottonseed meal (CSM) in the proportions of 7: 1, 6: 2, 5: 3 and 4: 4 (air-dry matter basis). Six sheep were given the pure SC diet and three sheep were given each of the mixed diets. Additionally, the CSM was also labelled with octatriacontane (C38) to investigate its use for labelling supplements. Due to unexpectedly low recoveries, C38 was not included in any estimation of diet composition or digestibility.
The inclusion of beeswax-labelled CSM in a SC diet resulted in lower faecal alkane recoveries (as proportions of alkane ingested; P ≤ 0·05). Within mixed diets, recoveries decreased significantly with increasing proportion of CSM, but this effect was significant (P < 0·05) only for alkanes consisting of 25, 26, 27 and 29 carbon-atoms. Estimates of diet composition were close to measured values. Daily SC intake and organic matter digestibility (OMD) differed by −3·7 to 7·2% and −2·0 to 5·7% from measured values if a mean faecal recovery, across diets, was applied for each alkane. Accuracy increased greatly if estimates were based upon faecal alkane recoveries for individual diets, instead of mean recoveries across diets (−0·3 to 0·9% and −0·2 to 0·0% for SC intake and OMD, respectively).
The results indicate that roughage intake can be estimated from a combination of known supplement intake and an estimate of diet composition, which obviates the need for separate alkane dosing to estimate intake. The method should be applicable in situations in which animals either normally receive supplements (e.g., dairy cows) or could readily be given supplements.
Estimation of feed intake by cattle using controlled-release capsules containing n-alkanes or chromium sesquioxide
- L. M. M. FERREIRA, M. OLIVÁN, M. A. M. RODRIGUES, K. OSORO, H. DOVE, A. DIAS-DA-SILVA
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- Journal:
- The Journal of Agricultural Science / Volume 142 / Issue 2 / April 2004
- Published online by Cambridge University Press:
- 19 October 2004, pp. 225-234
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An experiment was carried out to evaluate the utilization of the n-alkane technique and the chromium sesquioxide (Cr2O3)/acid insoluble ash (AIA) procedure to estimate feed intake of meadow hay by two breeds of cattle. The animals were housed in individual pens, and offered known amounts of meadow hay as the sole diet component. One group of 4 Barrosã cows (average weight, 457±24 kg) and another group of 4 Holstein–Friesian cows (average weight, 635±148 kg) were dosed with intra-ruminal controlled-release capsules (CRC) that contained alkane markers or Cr2O3 in separate capsules. During intake estimation, meadow hay and faeces were sampled twice daily. There was no significant effect of grab sampling time on the meadow hay intake estimation, due to the fact that no differences were observed in the faecal marker concentrations.
The mean real intakes, measured as the difference between the dry weight of feed offered each day and the dry weight of daily feed refusal, were 5·64 and 7·76 kg DM/day for Barrosã and Holstein–Friesian cows, respectively. For Barrosã cows the mean estimated intakes when using the CRC release rates documented by the manufacturer (MRR) were 5·66, 6·59 and 6·90 kg DM/day, using the Cr2O3/AIA procedure, C31[ratio ]C32 and C33[ratio ]C32 n-alkane pairs, respectively. For Holstein–Friesian cows the same markers gave values of 7·72, 8·51 and 8·95 kg DM/day, respectively. Mean daily intake estimation was improved when the release rate calculated as the reduction rate in CRCs payload performed in a additional experiment (CRR), was used. The differences from the real intake values, obtained using C31[ratio ]C32 and C33[ratio ]C32 alkane pairs, decreased from 950 and 1260 g/day to 140 and 420 g/day, respectively, for Barrosã cows and from 750 and 1190 g/day to 290 and 90 g/day for Holstein–Friesian cows. The intake estimation using the Cr2O3/AIA procedure was not affected by correcting the CRC release rate, because the release rates of both MRR and the CRR were similar.
The results indicate that controlled-release capsules provide a uniform marker release in cattle, but also suggest that to obtain accurate estimates of intake, it is better to measure release rates within the context of particular experiments.
The Kinetics of Calcite Growth: Interpreting Chemical Affinity-Based Rate Laws Through the Lens of Direct Observation
- Henry H. Teng, Patricia M. Dove, James J. De Yoreo
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- Journal:
- MRS Online Proceedings Library Archive / Volume 620 / 2000
- Published online by Cambridge University Press:
- 14 March 2011, M2.6.1
- Print publication:
- 2000
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Chemical affinity-based rate laws are used across the geochemical and materials communities to quantify mineral/material corrosion and growth kinetics. These rate expressions are founded in assumptions regarding reaction mechanism with little evidence for surface processes. Using Atomic Force Microscopy (AFM), this study demonstrates the dependence of growth kinetics upon the structures of dislocation sources. In situ observations show that the dominant mode of growth occurs by hillock development initiated at complex sources. Derivations of surface process-based rate expressions show a complex dependence of rate on chemical affinity. This dependence is approximated by second order affinity-based rate laws only under the special conditions that 1) growth proceeds by development of single sourced spirals and 2) growth occurs at very near equilibrium conditions where spiral formation is the only operative mechanism. This suggests that growth experiments that measure temporal changes in solution chemistry yield a composite rate that arises from the contributions of the different hillock types. Hence, chemical affinity-based rate laws do not generally give meaningful interpretations of growth mechanism. By combining direct observations with macroscopic methods that monitor temporal changes in solution chemistry, rate laws with greater predictive capabilities may be possible.
An evaluation of the effects of incisor dentition and of age on the performance of lactating ewes and their lambs
- H. Dove, J. A. Milne
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- Journal:
- Animal Production / Volume 53 / Issue 2 / October 1991
- Published online by Cambridge University Press:
- 02 September 2010, pp. 183-190
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- October 1991
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Ninety-six Border Leicester × Scottish Blackface ewes, aged 2 to 6 years, grazed perennial ryegrass pastures during lactation. The state of their incisor teeth was assessed at parturition on a scale from score 1 (sound teeth) to score 4 (poor teeth). Their live weights and condition scores during lactation were then related to incisor score and age by regression analysis. Lamb growth was similarly analysed. Herbage intakes and milk production were measured in a subset of 24 ewes.
Ewe live weights were significantly lower, per unit incisor score, by 2·2, 2·5 and 2·1 kg at days 22, 50 and 96 of lactation respectively. In ewes with twin lambs, the equivalent reductions were 1·6, 2·8 and 2·1 kg respectively. Reductions in condition score, whilst still significant, were less marked. After adjusting for the effects of incisor dentition, there was no effect of age on ewe live weight or condition score.
Incisor dentition did not markedly affect herbage intake or milk production, except in measurements at day 53 of lactation, where higher incisor scores resulted in significant reductions in the production of milk and its components. Effects on lamb performance were confined to twins, where live-weight gain to day 50 was reduced by 12·2 g/day, per unit increase in ewe incisor score. This resulted in reductions of 0·7 kg (day 50) and 0·9 kg (weaning) in the live weight of twin lambs.
Circadian variation in abomasal digesta flow in grazing ewes during lactation
- H. Dove, J. A. Milne, A. M. Sibbald, C. S. Lamb, H. A. McCormack
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- Journal:
- British Journal of Nutrition / Volume 60 / Issue 3 / November 1988
- Published online by Cambridge University Press:
- 09 March 2007, pp. 653-668
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- November 1988
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1. Lactating grazing ewes, fistulated at the rumen and abomasum were either not supplemented or offered, individually, 600 g/d of either pelleted, molassed sugar-beet pulp (‘energy’ supplement) or a pelleted 1:1 (w/w) mixture of this feed and formaldehyde-treated soya-bean meal (‘protein’ supplement). Digesta flows at the abomasum were estimated from the concentrations of the markers CrEDTA and ruthenium phenanthroline complex, during their administration by continuous intra-rumen infusion. Digesta samples were taken at 09.00 hours and at six further times at 4 h intervals. This was repeated 2 d later.
2. No significant difference in flow between days was noted. Daily flows of dry matter (DM) and non-ammonia-nitrogen (NAN) (g/d) in supplemented ewes were significantly higher than in unsupplemented ewes, both in total digesta and its particulate phase. However, there were significant differences between sampling times or significant interactions between sampling time and supplement treatment. The results were therefore examined by Fourier analysis for possible circadian variation in digesta flow. As there was marked between-animal variability in flow-rate, the digesta-flow values for each sampling time were re-expressed as percentages of the flows calculated from daily mean marker concentrations.
3. In unsupplemented animals, marked and significant circadian variation was then identified in the flow of DM, total N and NAN in both whole digesta and the particulate phase. There was also significant circadian variation in the flow of DM, total N and NAN in the digesta of the supplemented ewes. Curves were of the same general shape as those for unsupplemented animals, but some significant differences were found, principally for digesta NAN flow. In both supplemented and unsupplemented animals, peak flows occurred in the period 20.00-01.00 hours. The proportion of DM and NAN flowing in the particulate phase was relatively constant through the day for unsupplemented ewes, but significant circadian variation occurred for supplemented ewes.
4. The possible mechanisms generating the circadian variation in digesta flow, such as grazing behaviour and the rumen digestion of supplements, are discussed. Values are also presented to indicate the extent of the likely errors if digesta flows were estimated from samples which did not represent all stages of the circadian pattern.
Monitoring the fate of dietary proteins in rumen fluid using gel electrophoresis
- D. Spencer, T. J. V. Higgins, M. Freer, H. Dove, J. B. Coombe
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- Journal:
- British Journal of Nutrition / Volume 60 / Issue 2 / September 1988
- Published online by Cambridge University Press:
- 09 March 2007, pp. 241-247
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- September 1988
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1. When fractionated by sodium dodecylsulphate-polyacrylamide gel electrophoresis (SDS-PAGE), strained rumen fluid from sheep fed on pelleted lucerne (Medicago sativa) hay showed no major protein components that stain with Coomassie Blue. This feature made it possible to monitor the fate of individual polypeptides within a protein mixture incubated in rumen fluid in vitro.
2. Extracts from a number of seed meals (sunflower (Helianthus annuus), lupin (Lupinus angustifolius), rape (Brassica napus) and pea (Pisum sativum L.)), as well as casein and bovine serum albumin, were examined in this system. The protein components of each seed type showed a wide range of resistances to degradation. One protein in pea seeds (pea albumin 1), which is particularly rich in cysteine, was almost as resistant to rumen degradation as bovine serum albumin.
3. Analysis of synthetic-fibre-bag experiments by SDS-PAGE showed that the rate of loss of total protein from solid meal residues does not provide an index of the resistance of individual protein components of the meal to rumen degradation. While there was no qualitative change in the protein profile of residual pea-seed meal inside a synthetic-fibre bag, there was considerable variation in the rate at which individual, solubilized protein components were degraded in the surrounding rumen fluid.
Estimation of the intake of milk by lambs, from the turnover of deuterium- or tritium-labelled water
- H. Dove
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- Journal:
- British Journal of Nutrition / Volume 60 / Issue 2 / September 1988
- Published online by Cambridge University Press:
- 09 March 2007, pp. 375-387
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- September 1988
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1. The total water turnovers of grazing ewes and their lambs were estimated on days 9, 23, 44, 69 and 86 of lactation from the dilution of tritiated water injected into the dam and deuterium oxide injected into the offspring. The contribution of milk to the total water turnover of the lambs was estimated at the same times from the accumulation of tritium in their body water.
2. Mean total water turnover in the ewes was 6.5 litres/d over the entire period. In lambs, total turnover rose from 1459 ml/d at 9 d to 2791 ml/d at 86 d, and was closely related to live weight (r2 0.760, P < 0.001). The corrections to total water turnover, which were required because of the increasing body water pool size of the lambs during each measurement period, fell from +10.6% at 9 d to +3.7% at 86 d. All corrections were significant (P < 0.001).
3. The intake of water as milk fell throughout the study, from 1501 ml/d at 9 d to 471 ml/d at 86 d. Pool-size corrections were significant (P < 0.001). Milk intakes calculated from these results were 1816, 1054, 862, 742 and 588 ml/d at 9, 23, 44, 69 and 86 d of lactation. The rapid decline in milk intake reflected undernutrition of the ewes in early lactation.
4. The level of live-weight gain in early lactation was closely related to, and at a level expected from, the estimated milk intakes. From comparisons of estimated milk intakes with published estimates, it is concluded that the combined use of deuterium oxide and tritiated water results in accurate estimates of milk intake by the lamb throughout the ewe's lactation.
Dominance patterns and positional behaviour of sheep in yards
- H. Dove, R. G. Beilharz, J. L. Black
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- Journal:
- Animal Production / Volume 19 / Issue 2 / October 1974
- Published online by Cambridge University Press:
- 02 September 2010, pp. 157-168
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- October 1974
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1. Observations were conducted to ascertain the social dominance structure in two small groups of castrated male Corriedale sheep. In these and a third group, the order of the sheep past a fixed point was recorded, when they were moving either voluntarily or under force. Records were also made of the way in which the sheep distributed themselves spatially in a confined area, relative to one or two men simulating yard work. In a fourth group divided into two sub-groups, the social dominance structure was determined before and after the subgroups were mixed, to assess the effect of mixing.
2. The small groups showed a distinct social dominance hierarchy of a linear type, similar to that found in cattle and pigs. The dominance status of individual animals was correlated with their body weight, wither height and height at hocks. Dominance status within a subgroup remained stable following the mixing of sub-groups.
3. The sheep adopted consistent positions in forced movement, and in relation to one or two men simulating yard work. There was no consistency in voluntary movement. Dominant animals did not lead the forced movement, were usually some distance from man, and were widely scattered from each other.
4. Dominance status was closely related to positional behaviour.
Light Therapy in Mental Hospitals
- H. Dove Cormac
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- Journal:
- Journal of Mental Science / Volume 75 / Issue 310 / July 1929
- Published online by Cambridge University Press:
- 19 February 2018, pp. 410-419
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- July 1929
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The value of sunlight in the maintenance of health has been recognized from early ages, and history records sun-worship by many nations in the past as well as at the present time. In Europe records exist of the use of the light of the sun for medical and surgical purposes since before the Christian era, but it was only towards the end of the last century that its possibilities began to be studied and the value of the electric arc lamp as a substitute recognized. In 1893 Finsen demonstrated the value of sunlight and electric arc radiation in the treatment of lupus, and at the beginning of the present century Bernhard of Samaden treated wounds and tuberculous lesions with sunlight. In 1903 Rollier opened his first clinic at Leysin, where he obtained excellent results in the treatment of tuberculosis, especially of the surgical type, by insolation in the brilliant Alpine sunshine. In 1908 Gauvain introduced heliotherapy at Hayling Island and at Alton. Nagelschmidt used the air-cooled quartz mercury vapour lamp for general irradiation in the same year, and in 1913 Reyn commenced the use of the carbon arc for the same purpose. The value of ultra-violet rays in the cure of rickets was not recognized till demonstrated by Huldschinsky in 1918, though Palm (1), as early as 1890, urged that deficiency of sunshine was a cause of the condition.