scholarly journals Review of data on hoof growth in normal and laminitic equines suggests a new aetiology for acute laminitis

2018 ◽  
Author(s):  
Thomas P Ryan
Keyword(s):  
Seasonal Variation ◽  
Growth Rates ◽  
Developmental Phase ◽  
Dorsal Region ◽  
Dorsal Wall ◽  
Accelerated Growth ◽  
The Difference ◽  
Equine Hoof ◽  
Rates Of Growth ◽  
Insight Into

Background. To gain a greater insight into normal and laminitic hoof growth and to be able to make comparisons between the two groups. Methods. Ten normal and three laminitic equines completed the survey, each hoof was marked with a horizontal file mark in three places, the dorsal wall and each medial and lateral quarter at about 1cm below the coronary band. Measurement of the progression of the file mark was made every 28 days, a total of 1,872 measurements were made. Results. Equine hoof growth rates showed seasonal variation with greater rates of growth during the summer months and slower rates during the winter. In normal horses growth was slower at the quarters compared to the dorsal region but the difference was not statistically significant (p>0.05). During the summer months laminitic hoof growth at the quarters was significantly faster than at the laminitic dorsal region (p< 0.05). The rate of accelerated growth at the laminitic quarters reduced during the winter months and was not statistically significant (p>0.05). Discussion. The results of this measurement survey highlighted that laminitic hoof growth is remarkably different at the quarters. This raises the question of when the transition from normal to laminitic hoof growth takes place. Traditionally changes in hoof shape during laminitis have been assumed to be a consequence of the acute phase but this has never been confirmed. The possibility exists that abnormal hoof growth could commence early in the developmental phase, the implications of abnormal hoof growth commencing at this stage are profound. A new etiology for equine laminitis then becomes possible, based on accelerated hoof growth at the quarters inducing the hoof capsule to change in shape; this process would have the capacity to subject the underlying dorsal dermal laminae to forces of extension which would be capable of destroying the laminal interface.

scholarly journals Review of data on hoof growth in normal and laminitic equines suggests a new etiology for acute laminitis

2018 ◽  
Author(s):  
Thomas P Ryan
Keyword(s):  
Seasonal Variation ◽  
Growth Rates ◽  
Developmental Phase ◽  
Dorsal Region ◽  
Dorsal Wall ◽  
Accelerated Growth ◽  
The Difference ◽  
Equine Hoof ◽  
Rates Of Growth ◽  
Insight Into

Background. To gain a greater insight into normal and laminitic hoof growth and to be able to make comparisons between the two groups. Methods. Ten normal and three laminitic equines completed the survey, each hoof was marked with a horizontal file mark in three places, the dorsal wall and each medial and lateral quarter at about 1cm below the coronary band. Measurement of the progression of the file mark was made every 28 days, a total of 1,872 measurements were made. Results. Equine hoof growth rates showed seasonal variation with greater rates of growth during the summer months and slower rates during the winter. In normal horses growth was slower at the quarters compared to the dorsal region but the difference was not statistically significant (p>0.05). During the summer months laminitic hoof growth at the quarters was significantly faster than at the laminitic dorsal region (p< 0.05). The rate of accelerated growth at the laminitic quarters reduced during the winter months and was not statistically significant (p>0.05). Discussion. The results of this measurement survey highlighted that laminitic hoof growth is remarkably different at the quarters. This raises the question of when the transition from normal to laminitic hoof growth takes place. Traditionally changes in hoof shape during laminitis have been assumed to be a consequence of the acute phase but this has never been confirmed. The possibility exists that abnormal hoof growth could commence early in the developmental phase, the implications of abnormal hoof growth commencing at this stage are profound. A new etiology for equine laminitis then becomes possible, based on accelerated hoof growth at the quarters inducing the hoof capsule to change in shape; this process would have the capacity to subject the underlying dorsal dermal laminae to forces of extension which would be capable of destroying the laminal interface.

scholarly journals Review of data on hoof growth in normal and laminitic equines suggests a new aetiology for acute laminitis

2018 ◽  
Author(s):  
Thomas P Ryan
Keyword(s):  
Seasonal Variation ◽  
Growth Rates ◽  
Developmental Phase ◽  
Dorsal Region ◽  
Dorsal Wall ◽  
Accelerated Growth ◽  
The Difference ◽  
Equine Hoof ◽  
Rates Of Growth ◽  
Insight Into

Background. To gain a greater insight into normal and laminitic hoof growth and to be able to make comparisons between the two groups. Methods. Ten normal and three laminitic equines completed the survey, each hoof was marked with a horizontal file mark in three places, the dorsal wall and each medial and lateral quarter at about 1cm below the coronary band. Measurement of the progression of the file mark was made every 28 days, a total of 1,872 measurements were made. Results. Equine hoof growth rates showed seasonal variation with greater rates of growth during the summer months and slower rates during the winter. In normal horses growth was slower at the quarters compared to the dorsal region but the difference was not statistically significant (p>0.05). During the summer months laminitic hoof growth at the quarters was significantly faster than at the laminitic dorsal region (p< 0.05). The rate of accelerated growth at the laminitic quarters reduced during the winter months and was not statistically significant (p>0.05). Discussion. The results of this measurement survey highlighted that laminitic hoof growth is remarkably different at the quarters. This raises the question of when the transition from normal to laminitic hoof growth takes place. Traditionally changes in hoof shape during laminitis have been assumed to be a consequence of the acute phase but this has never been confirmed. The possibility exists that abnormal hoof growth could commence early in the developmental phase, the implications of abnormal hoof growth commencing at this stage are profound. A new etiology for equine laminitis then becomes possible, based on accelerated hoof growth at the quarters inducing the hoof capsule to change in shape; this process would have the capacity to subject the underlying dorsal dermal laminae to forces of extension which would be capable of destroying the laminal interface.

The Relative Growth of Parts in Palaemon Carcinus

1930 ◽  
Vol 7 (2) ◽  
pp. 165-174
Author(s):  
M. A. TAZELAAR
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Linear Measurements ◽  
Relative Growth ◽  
Male And Female ◽  
Relative Growth Rates ◽  
Rate Of Growth ◽  
The Difference ◽  
Rates Of Growth

Linear measurements of certain appendages and the carapace of P. carcinus were made and plotted in various ways. The following conclusions were drawn: 1. The cheliped shows heterogonic growth in both male and female, but more markedly in the male, the values of k being: male 1.8 and female 1.48 2. The pereiopods in both male and female are slightly heterogonic. The relative growth rates are graded from p3 to p5, that of p3 being slightly greater than that of p5 3. Of the ordinary pereiopods the rate of growth of p1 is the smallest in the male, but the largest in the female. 4. The difference between the rates of growth of p1 and p3 in male and female is greatest where the rate of growth in the heterogonic organ, the cheliped, is most excessive in the male. 5. The growth of the 3rd maxilliped is slightly negatively heterogonic, the value of k in the male being 0.93 and in the female 0.95. Hence there seems to be a correlation between the marked heterogony in the cheliped on the growth rate of neighbouring appendages. In those immediately posterior to the cheliped the growth rate is increased and in those anterior decreased.

The modulus of elasticity of equine hoof wall: implications for the mechanical function of the hoof.

1996 ◽  
Vol 199 (8) ◽  
pp. 1829-1836 ◽  
Author(s):  
J E Douglas ◽  
C Mittal ◽  
J J Thomason ◽  
J C Jofriet
Keyword(s):  
Moisture Content ◽  
Modulus Of Elasticity ◽  
Weight Bearing ◽  
Outer Wall ◽  
Wall Material ◽  
Detectable Effect ◽  
Dorsal Wall ◽  
The Mean ◽  
The Difference ◽  
Equine Hoof

During normal weight-bearing and locomotion, the equine hoof wall deforms in a consistent pattern; the proximal dorsal wall rotates caudo-ventrally about the distal dorsal border and there is latero-medial flaring posteriorly. The aim of this study is to examine whether there are regional differences in the modulus of elasticity of hoof wall material and whether such differences correlate with the pattern of deformation which occurs in vivo. The modulus of elasticity of equine hoof wall was determined in tension and compression for samples from six forefeet. Samples were tested at the mid-point of the inner and outer halves of the wall thickness at two positions along the proximo-distal axis of the dorsal wall, and from the mid-point of its thickness at the lateral and medial quarters. Test samples were oriented both parallel and perpendicular to the tubules that characterise the microstructure of the wall. The colour of each sample was noted, and the moisture content measured. The range in the mean modulus of elasticity for all samples and tests was 460-1049 MPa, the dorsal outer wall having the highest values, the dorsal inner wall the lowest, and the quarters having intermediate values. The mean value obtained for the quarters was similar to the average of the values for the dorsal inner and outer walls. At all sites, the modulus of elasticity was marginally higher in compression than in tension, possibly owing to microstructural defects. The difference in stiffness between the outer wall and the inner wall was inversely related to moisture content. The difference in stiffness between the dorsal outer and inner walls demonstrates that the equine hoof wall has a comparatively rigid external capsule with a lining of lower stiffness. This arrangement presumably provides some stress protection to the internally adjacent living tissues. The similarity in stiffness between the samples from the quarters and the mean of the two dorsal wall sites suggests that the wall at the quarters has a similar change in stiffness across its thickness as the dorsal wall. However, the reduced thickness of the wall at the quarters compared with the dorsal wall means that, functionally, the quarters are more flexible than the dorsal wall. This will facilitate the flaring of the lateral and medial walls which occurs during weight-bearing. Anisotropy was evident only in tensile tests of the dorsal wall samples. Contrary to popular assertions that white hooves are mechanically inferior, horn pigmentation had no detectable effect on stiffness.

Differential Growth Rates in Singapore and Hong Kong

2017 ◽  
Author(s):  
Yue Chim Richard Wong
Keyword(s):  
Human Capital ◽  
Hong Kong ◽  
Growth Rates ◽  
Voluntary Organizations ◽  
Differential Growth ◽  
Free Markets ◽  
The World ◽  
The Difference ◽  
Rates Of Growth ◽  
Important Form

The crucial driver of the difference in growth rates between Hong Kong and Singapore – two of the freest market economies in the world – is their different rates of growth in human capital. Free markets in labor, capital, and land allow these resources to be allocated more efficiently, but you cannot achieve growth and productivity increases if you do not invest in capital. In a modern economy, the most important form of capital is human capital. Human capital markets are imperfect, so there is an important role for government and nongovernment charities and voluntary organizations to play in fostering and financing investment in human capital.Hong Kong must not lose any more time getting its act together on human capital.

scholarly journals The integration of plant behaviour. IV.-Geotropism and growth-substance

1931 ◽  
Vol 108 (759) ◽  
pp. 537-545 ◽  
Keyword(s):  
Zea Mays ◽  
Growth Rates ◽  
Growth Substance ◽  
Root Tips ◽  
The Difference ◽  
Rates Of Growth ◽  
Plant Behaviour

In a previous paper (1929) we referred to an ingenious experiment by Cholodny (1924), who, working with Zea mays , found that the sensitivity to gravity of decapitated roots can be largely restored not only (as was already known) by replacing their own tips, but also and even better, by placing on them the tips of coleoptiles. whichever tip was places upon them, the roots curved down wards. Since decapitated coleoptiles also known to have their sensitivity to gravity restored if their tips are replaced, and since they respond by curving upwards, the question at once suggests itself-how is it that the coleoptile tip causes the stumps of coleoptile and root to respond to gravity by curving in opposite directions ? It seems clear that the difference in the responses must somehow depend upon the different natures of the stumps, and Cholodny considers that these are so constituted that their growth rates are oppositely affected by the same substance which diffuses into them from the coleoptile tips, the growth of the coleoptile being accelerated and that of the root being retarded. Stark also (1927, p. 8) adopts a view which in this respect is similar. Naturally in order to explain the curvatures along these lines, it is necessary to suppose further that this substance for some reason flows to the lower sides of the horizontal stumps in greater concentration than to the upper sides. That a substance accelerating the growth of the coleptile of Avena really does diffuse out of its tip had been made very probable by Söding (1925) and Went has since rigorously established the fact (1928). Cholodny supports his theory by finding that the rates of growth of decapitated roots and coleoptiles are affected in opposite senses if either root tips or coleoptile are effected in opposited senses if either root tips or coleoptile tips are placed upon them, the roots being retarded by both kinds of tips are placed upon them, the roots being retarded by both kinds of tip and the coleptiles being accelerated by both kinds (1924, 1926 and 1928). We have been led on to investigate for ourselves the effects of the two kinds of tip on the growth of the root, after first confirming cholodny's original discovery.

Delayed transmission of a parasite is compensated by accelerated growth

Parasitology ◽  
2005 ◽  
Vol 131 (5) ◽  
pp. 647-656 ◽  
Author(s):  
T. HAKALAHTI ◽  
M. BANDILLA ◽  
E. T. VALTONEN
Keyword(s):  
Growth Rates ◽  
Free Living ◽  
Host Seeking ◽  
Age Dependent ◽  
Food Shortages ◽  
Catch Up ◽  
Argulus Coregoni ◽  
Accelerated Growth ◽  
Rates Of Growth ◽  
Delayed Growth

Compensatory or ‘catch-up’ growth following prolonged periods of food shortages is known to exist in many free-living animals. It is generally assumed that growth rates under normal circumstances are below maximum because elevated rates of growth are costly. The present paper gives experimental evidence that such compensatory growth mechanisms also exist in parasitic species. We explored the effect of periodic host unavailability on survival, infectivity and growth of the fish ectoparasiteArgulus coregoni. Survival and infectivity ofA. coregonimetanauplii deprived of a host for selected time periods were age dependent, which indicates that all metanauplii carry similar energy resources for host seeking. Following the periods off-host, metanauplii were allowed to settle on rainbow trout and were length measured until they reached gravidity. During early development on fish, body length of attachedA. coregoniwas negatively correlated with off-host period indicating a mechanism that creates size variance in an attached parasite cohort originally containing equal amounts of resources. However, over time the size differences between parasites became less pronounced and eventually parasites that were kept off-host for longest periods of time reached the length of those individuals that had been allowed to infect a host sooner.A. coregonithus appears to compensate for delayed growth resulting from an extended host searching period by elevated growth rates, although we show that such accelerated growth incurred a cost, through decreased life-expectancy.

Measurement of growth rates for single crystals and pressed tablets of CuSO4.5 H2O on a rotating disc

1989 ◽  
Vol 54 (11) ◽  
pp. 2951-2961 ◽  
Author(s):  
Miloslav Karel ◽  
Jaroslav Nývlt
Keyword(s):  
Growth Rate ◽  
Single Crystal ◽  
Single Crystals ◽  
Growth Rates ◽  
Diffusion Coefficients ◽  
Preferred Orientation ◽  
Rotating Disc ◽  
Dissolution Rates ◽  
Rates Of Growth ◽  
Good Agreement

Measured growth and dissolution rates of single crystals and tablets were used to calculate the overall linear rates of growth and dissolution of CuSO4.5 H2O crystals. The growth rate for the tablet is by 20% higher than that calculated for the single crystal. It has been concluded that this difference is due to a preferred orientation of crystal faces on the tablet surface. Calculated diffusion coefficients and thicknesses of the diffusion and hydrodynamic layers in the vicinity of the growing or dissolving crystal are in good agreement with published values.

Effects of turbidity on prey consumption and growth in brook trout and implications for bioenergetics modeling

2001 ◽  
Vol 58 (2) ◽  
pp. 386-393 ◽  
Author(s):  
John A Sweka ◽  
Kyle J Hartman
Keyword(s):  
Growth Rates ◽  
Brook Trout ◽  
Specific Growth ◽  
Abiotic Factors ◽  
Foraging Strategies ◽  
Turbid Water ◽  
Daily Consumption ◽  
Consumption Rates ◽  
The Difference ◽  
Specific Growth Rates

Brook trout (Salvelinus fontinalis) were held in an artificial stream to observe the influence of turbidity on mean daily consumption and specific growth rates. Treatment turbidity levels ranged from clear (<3.0 nephelometric turbidity units (NTU)) to very turbid water (> 40 NTU). Observed mean daily specific consumption rates were standardized to the mean weight of all brook trout tested. Turbidity had no significant effect on mean daily consumption, but specific growth rates decreased significantly as turbidity increased. Brook trout in turbid water became more active and switched foraging strategies from drift feeding to active searching. This switch was energetically costly and resulted in lower specific growth rates in turbid water as compared with clear water. Bioenergetics simulations were run to compare observed growth with that predicted by the model. Observed growth values fell below those predicted by the model and the difference increased as turbidity increased. Abiotic factors, such as turbidity, which bring about changes in the activity rates of fish, can have implications for the accuracy of predicted growth by bioenergetics models.

Taking Stock of Genetic Concepts in Fisheries Management

1991 ◽  
Vol 48 (4) ◽  
pp. 722-731 ◽  
Author(s):  
R. W. Gauldie
Keyword(s):  
Fisheries Management ◽  
Growth Rates ◽  
Allele Frequencies ◽  
Frequency Variation ◽  
Sustainable Yield ◽  
Fish Stocks ◽  
Meristic Count ◽  
Intuitive Idea ◽  
Selection Mechanisms ◽  
Insight Into

The historical development of the idea of isolated stocks of fish that can be managed as separate management units has been as strongly tied to the intuitive idea of separate races as it has been to the practical necessities of jurisprudence and the estimation of both biomass and sustainable yield by fisheries managers. Demonstrating the existence of isolated fish stocks and delineating their boundaries has generally proved unsuccessful. Various techniques ranging from meristic count differences to polymorphic allelism have usually failed. However, in the pursuit of isolated stocks, biochemists have uncovered a great deal of information about the variation of polymorphic allele frequencies over time and space. Following the shift in opinion away from stochastic to natural selection mechanisms in allele frequency variation, it is evident that the observed variation in allele frequencies allows more insight into the biology of fishes than into the breeding structure of populations. These insights argue against the idea of isolated stocks of fish with homogeneous growth rates that are the basis of the sustainable yield models in favour of migration-linked stocks with heterogeneous growth rates.

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