«Measurements of Trackways as a Method for Assessing Locomotion in Dairy Cows Evgenij Telezhenko Thesis (Licentiate) Sveriges Lantbruksuniversitet ...»
Measurements of Trackways as a
Method for Assessing Locomotion
in Dairy Cows
Sveriges Lantbruksuniversitet Skara 2005 Avhandling 2
Institutionen för husdjurens miljö och hälsa
Avdelningen för Produktionssjukdomar
Swedish University of Agricultural Sciences Thesis 2
Department of Animal Environment and Health
Section of Production diseases
Telezhenko, E. 2005. Measurements of trackways as a method for assessing locomotion in dairy cows. Licentiate thesis.
ISSN 1652-750X, ISBN 91-576-6852-3 The aim of this study was to assess whether locomotion parameters obtained by measurements of cow trackways are reliable and sufficiently sensitive to describe locomotion in non-lame and lame dairy cows on different floors. Thirty-two non-lame cows were used to study the reliability of the trackway measurements. The cows were tested twice over three weeks and measurements from four consecutive strides were used during each test session. To study the effect of different floors on locomotion, 25 non-lame cows
and eleven cows with different lameness degrees were tested on five different surfaces:
solid and slatted concrete, both with and without 20 mm thick elastic rubber mats, and wet, compacted sand. The reliability of the measurements varied from moderate to low, with measurements relating to inter-limb coordination being most inconsistent. The slippery slatted concrete floor caused restricted locomotion in so far as the strides were significantly shorter here than on all the other floors. Use of yielding rubber mats resulted in a locomotion more similar to that on the sand path. Lameness had an effect on shortening strides and steps, but in most cases the animals’ reaction to different floorings was similar in lame and healthy cows. Step asymmetry due to lameness was decreased when cows walked on the soft surfaces. It was concluded that a trackway measurement system is a suitable method to use in field locomotion studies and that the system is useful in identifying differences in kinematics on different floor types. Since there is a relatively high inconsistency in cow walking it is beneficial to use measurements of several strides to obtain a representative gait pattern.
Keywords: locomotion, dairy cows, gait analysis, floor, concrete, rubber, kinematics Author’s address: Evgenij Telezhenko, Department of Animal Environment and Health, SLU, PO Box 234, SE-532 23 Skara, Sweden (email@example.com) “… No doubt it appeared to you to be a mere trampled line of slush, but to my trained eyes every mark upon its surface had a meaning.
There is no branch of detective science which is so important and so much neglected as the art of tracing footsteps. Happily, I have always laid great stress upon it, and much practice has made it second nature to me …” Arthur Conan Doyle, A Study in Scarlet, 1887.
Contents Background, 7 Introduction, 7 Cattle and locomotion, 7 Need for locomotion, 7 Locomotion and environment, 8 Methods of studying locomotion in cattle, 9 Subjective methods, 9 Objective methods, 9 Trackway measurements, 10 Aims, 11 Summary of materials and methods, 12 Animals and housing, 12 Gait assessment, 12 Statistical analysis, 14 Paper I, 14 Paper II, 15 Summary of results, 16 Paper I, 16 Paper II, 16 General discussion, 17 Trackway measurements and error due to measurements, 17 Reproducibility of gait, 17 Quality of gait, 21 Definition of good locomotion, 18 Indicators of cow locomotion comfort, 18 Conclusions, 21 Svensk sammanfattning, 22 Резюме, 24 References, 27 Acknowledgements, 31 Appendix Papers I-II The present thesis is based on the following papers, which will be referred to in
the text by their Roman numerals:
I Telezhenko, E. Measurement of spatial gait parameters from footprints of dairy cows. (Manuscript) II Telezhenko, E. & Bergsten, C. 2005. Influence of floor type on the locomotion of dairy cows. Applied Animal Behaviour Science, (in press).
Paper II has been reproduced by kind permission of the journal concerned.
Background The need of cows for free movement and, coupled with freedom of movement, expression of natural behaviour is easier to meet in a loose housing system than in a tie stall system. Cubicle systems are becoming increasingly common in highperforming dairy herds. The floor design is one of the most critical aspects of loose housing systems because of its direct effect on the cattle’s locomotor apparatus (Stefanowska et al., 1998). Most walkways in cattle houses are made of concrete because it is fairly durable, cheap and resistant to wear and has acceptable hygienic characteristics. However, the hardness, abrasiveness and slipperiness of concrete floors contribute to foot and leg lesions resulting in lameness (Webb & Nilsson, 1983; Bergsten & Frank, 1996; Manske et al., 2002;
Sommers, 2004). For a long time lameness in cattle has been recognised as a large economic problem. It is difficult to appreciate the real extent of the economic loss, however, because lameness involves both direct costs (labour and veterinary treatment) and indirect costs (decreased milk yield, weight loss, impaired fertility, low carcass price, etc). In addition, lameness is a sign of discomfort and pain, and alters the cow’s sensation of pain(Whay, Waterman & Webster, 1997). Therefore lameness is an important welfare issue (Logue, McNulty & Nolan, 1998).
Moreover, poor floor quality as well as lameness can alter the degree of social and sexual activities in cows and consequently also influences cows’ well-being and fertility (Zeeb, 1983; Benz, 2002).
Improved flooring in dairy cow houses is a much discussed topic but few objective assessments have been published of cows’ locomotion on different floors (Phillips & Morris, 2000, 2001). For an objective evaluation of locomotion comfort on a particular floor, we need a method that does not interfere with the cows’ natural behaviour in the actual environment. It seems essential for future practical applications of quantitative gait analysis to establish whether or not results from the single gait evaluation are representative of a cow’s overall gait performance. Repeatability and reproducibility over time of kinematic variables have not previously been studied in cattle.
Cattle and locomotion Need for locomotion Locomotion is part of the normal behavioural repertoire of cattle (Albright & Arave, 1997). Cattle move to feed and walk to the water trough, to interact with herdmates during social and sexual behaviour and to seek a birth site or shelter.
Cattle have an innate motivation for locomotion, which is increased with time of confinement (Loberg et al., 2004). Locomotion maintains adequate blood circulation, stimulates muscular system development and provides increased fitness (Zeeb, 1983; Gustafson, 1993). In their natural environment cattle are able to range over large areas in search of feed. Although extremely long distances covered (up to 40 km per day) reduce feed intake and milk production, cattle need to walk at least 3–4 km per day to keep in good physical shape (Phillips, 1993).
Locomotion and environment The physical properties of the environment through which an animal moves have a tremendous effect on the evolution of the way and dynamics of its locomotion (Dickinson et al., 2000). Movement on land requires that animals exceed gravity to support and move their bodies and accommodate any changes in the terrain (Biewener, 2003). Like all domestic mammals, cattle rely primarily on their limbs for movement, and the angulation and arrangement of the limb musculature provide strong evidence that their locomotor apparatus has mainly been developed for forward motion (Nickel et al., 1986).
European domestic cattle (Bos taurus) are descended from the aurochs (Bos primigenius), big animals which lived in transitional areas of woodland interspersed with open spaces (Baars et al., 2003). This means that the locomotor system of cattle evolved in an environment with plenty of space and yielding ground surfaces. Although the domestication of cattle started in about 7 000 BC this fact has probably not had a major effect on the basic dynamics of cattle locomotion, since animals were still grazed in conditions similar to their natural habitat.
When housing for cattle was introduced the animals were usually tied or were kept in a very limited space. Hence there was very little need for selection, either natural or artificial, for development of a locomotion system that was to be more suitable for an environment different from the natural one.
With the relatively recent introduction of cubicle housing, which ought to promote free movement of the animals indoors, the problem of arranging walking surfaces emerged. For several economic and practical reasons, the space for locomotion was provided in the passageways between cubicles and the majority of the floors were made of concrete. Although housed cattle do not need to cross large distances to feed, there is still a significant amount of locomotion associated with social and other activities (Albright & Arave, 1997). As a result, the cows, which have a locomotion system adapted for moving through grassland at the edge of forests, were forced to move in a confined environment, sometimes with low light intensity and unclean, hard, slippery and/or too abrasive walking surfaces (Zeeb, 1983; Phillips et al., 2000; Phillips & Morris, 2000, 2001).
Because of the contrast between the terrain in the natural habitat of cattle and the flooring in cubicle systems it is not surprising that lameness, defined as a severe disturbance of locomotion, is more common in the cubicle systems than on a pasture (Faye & Lescourret, 1989; Boelling & Pollott, 1998) or even in tie stalls (Maton, 1987; Faye & Lescourret, 1989; Bergsten & Herlin, 1996; Cook, 2003).
Apart from the lameness effect, today the general comfort of locomotion in cattle is in focus. The limited space and slatted concrete floors in cubicle houses seem to reduce cows’ locomotion activity (Zeeb, 1987). It has been shown that keeping cows tied or on slatted concrete floors in loose housing without access to pasture distorts their normal locomotion (Herlin & Drevemo, 1997).
Methods of studying locomotion in cattle Subjective methods Subjective locomotion assessment in cattle is a method commonly used by veterinary clinicians to estimate the quality of gait, in which most attention is devoted to determination of the degree of lameness. The most well-known scoring system for cattle locomotion has been published by Manson & Leaver (1988).
This system uses a nine-point score reflecting small changes in locomotion leading to lameness. More simple scoring systems have been used to categorise the degree of lameness severity (Tranter & Morris, 1991; Whay et al., 1997). Sprecher, Hostetler & Kaneene (1997) have developed a system focusing (along with gait scoring) on the back posture, a system that was later adapted and used by several authors (Uchida et al., 2001; Juarez et al., 2003).
While lameness scoring can help in evaluation of the disorder, it does not provide sufficient objective measures of gait. Although it is possible to compare the locomotion scoring results of different studies, it should be noted that the accuracy of scoring is strongly influenced by the observer’s skill and perception (Whay & Main, 1999). It has been demonstrated that use of gait analysis with quantitative (kinematic) methods is more precise than results obtained through subjective locomotion scoring (Keegan et al., 1998).
Objective methods Kinematic and kinetic analyses have been successfully used to study gait in domestic animals, primarily horses (Clayton & Schamhardt, 2001; Barrey et al., 1999). Kinetics is a science that studies the causes of motion, explaining them by the force applied to the body, its mass distribution and its dimensions. Marey (1873) was the first researcher to use a pressure sensor under the horse’s hoof to measure hoof-ground contact duration at various gaits. The modern sensor technology today allows recording of ground reaction forces over a large range of conditions (Roepstorff & Drevemo, 1993). The kinetics of cattle locomotion has been studied by Webb & Clark (1981) and Scott (1987). Van der Tol et al. (2003) used pressure sensors in combination with a force plate to study ground reaction forces and between-/within-claw pressure distribution in cows walking on a flat surface.
Kinematics describes the geometry of animal movement, studying changes in the position of the body parts during a specified time. The first kinematic animal locomotion study using chronophotography was performed by Muybridge (1887).
Since then many kinematic studies of animals have been performed and at present the majority of kinematic studies are carried out with videographic or optoelectronic systems consisting of integrated hardware and software components (Clayton & Schamhardt, 2001). However, only a few published studies have applied quantitative measurements of locomotion to cows (Herlin & Drevemo, 1997; Phillips & Morris, 2000, 2001). In recent years a new interest has emerged for studying cow kinematics by quantitative methods including standard motion systems (Chida et al., 2004) and a treadmill (Meyer et al., 2004). The new studies have also used a larger animal material. Flower, Sanderson & Weary (2004), for instance, used 46 cows to study biomechanics related to claw pathologies utilising a two-dimensional (2-D) motion system.
Trackway measurements While many of the sophisticated motion analysis systems are highly accurate, they may not be the optimal choice for wide implementation of objective locomotion measurements in cattle because of high cost and some procedural difficulties. Such drawbacks precipitate the need for validation and use of an inexpensive, objective gait analysis system which is possible to use in a livestock barn environment.
Linear kinematic data can be obtained by measuring the space between footprints, trackway measurements (Sukhanov, 1974). Assessment of trackways is a simple way to obtain information about animal locomotion when direct observations are impossible, as in the case of extinct animals. The first intensive study of fossil tracks was carried out by Professor Edward Hitchcock (1836).