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Hillidge, C. J., & Lees, P. (1975). Cardiac output in the conscious and anaesthetised horse. Equine Vet J, 7(1), 16–21.
Abstract: Cardiac output in the horse was measured before and at predetermined times during 2-hour periods of thiopentone-halothane and thiopentone-diethyl ether anaesthesia. Left ventricular stroke volume was decreased to a similar extent during anaesthesia with each volatile agent, but a greater reduction in cardiac output occurred during halothane anaesthesia. This finding reflected the differing effects of halothane and ether on heart rate, a slight bradycardia occurring with the former agent while ether produced a small degree of tachycardia. The latter effect was attributed to enhanced sympathoadrenal activity. Changes in cardiac output and stroke volume were considered in relation to other factors, including arterial blood pH and tensions of oxygen and carbon dioxide. Positive correlations between some of these variables and cardiac function were established. With both volatile agents the reductions in stroke volume and cardiac output were related to the duration of anaesthesia, being greatest during the early stages. Possible reasons for the tendency of stroke volume and cardiac output to return towards control levels are discussed.
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Lees, P., & Tavernor, W. D. (1970). Influence of halothane and catecholamines on heart rate and rhythm in the horse. Br J Pharmacol, 39(1), 149–159.
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Aureli, F., Preston, S. D., & de Waal, F. B. (1999). Heart rate responses to social interactions in free-moving rhesus macaques (Macaca mulatta): a pilot study. J Comp Psychol, 113(1), 59–65.
Abstract: Heart rate telemetry was explored as a means to access animal emotion during social interactions under naturalistic conditions. Heart rates of 2 middle-ranking adult females living in a large group of rhesus macaques (Macaca mulatta) were recorded along with their behavior. Heart rate changes during 2 types of interactions were investigated, while controlling for the effects of posture and activity. The risk of aggression associated with the approach of a dominant individual was expected to provoke anxiety in the approachee. This prediction was supported by the heart rate increase after such an approach. No increase was found when the approacher was a kin or a subordinate individual. The tension-reduction function of allogrooming was also supported. Heart rate decelerated faster during the receipt of grooming than in matched control periods.
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Waran, N. K., Robertson, V., Cuddeford, D., Kokoszko, A., & Marlin, D. J. (1996). Effects of transporting horses facing either forwards or backwards on their behaviour and heart rate. Vet. Rec., 139(1), 7–11.
Abstract: The effects of transporting horses facing either forwards or backwards were compared by transporting six thoroughbred horses in pairs in a lorry on one journey facing in the direction of travel, and on another journey facing away from the direction of travel, over a standard one-hour route. Heart rate monitors were used to record their heart rate before, during and after the journey and the horses' behaviour was recorded by scan sampling each horse every other minute. The average heart rate was significantly lower (P < 0.05) when the horses were transported facing backwards, and they also tended to rest on their rumps more (P = 0.059). In the forward-facing position, the horses moved more frequently (P < 0.05) and tended to hold their necks in a higher than normal position and to vocalise more frequently (P = 0.059). During loading the average peak heart rate was 38 bpm lower (P < 0.05) when the horses were backed into the horse box for rear-facing transport than when they were loaded facing forwards. However, there was no difference between transport facing forwards or backwards in terms of the peak unloading heart rate, or the average heart rate during loading or unloading. The horses seemed to find being transported less physically stressful when they were facing backwards than when they were facing forwards.
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Gutierrez Rincon, J. A., Vives Turco, J., Muro Martinez, I., & Casas Vaque, I. (1992). A comparative study of the metabolic effort expended by horse riders during a jumping competition. Br J Sports Med, 26(1), 33–35.
Abstract: The three main Olympic horse riding disciplines are dressage, jumping, and three-day eventing (including dressage, cross country and jumping). In the jumping discipline (obstacle race), the 'team' (horse rider) is judged under the different conditions that might take place in a varied run. The horse is expected to show power and ability; the rider must show riding skill and good physical condition. However, the different conditions encountered by the rider during competition (duration of event, continuous isometric working level, especially in the inferior trunk, lead us to consider the need for a rider to develop different metabolic pathways to meet the high energy requirements of the competition.
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Cattell, R. B., & Korth, B. (1973). The isolation of temperament dimensions in dogs. Behav Biol, 9(1), 15–30.
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Aerts, J. - M., Gebruers, F., Van Camp, E., & Berckmans, D. (2008). Controlling horse heart rate as a basis for training improvement. Computers and Electronics in Agriculture, 64(1), 78–84.
Abstract: Equine training methods, and consequently, performance times have improved little since the last decades. With advances in measuring signals on-line by means of several new technologies and analytical procedures, and processing these signals immediately with strong and compact processors, it may be possible to develop new training methods. In this research, the objective was to explore the possibilities of using modern model-based algorithms to control the heart rate of horses (bpm) on-line by means of the control input running speed (km/h). Forty-five experiments with five horses and four riders were carried out to generate measurements of physiological status during running. The dynamical characteristics of each horse were quantified using linear discrete transfer function models. The dynamic response of heart rate to step changes in running speed were accurately described. In 90% of the cases, a first-order model gave the best fit. For 69% of the models, the r2 was higher than 0.90 and for 34% of the models, the r2 was even higher than 0.95. In a next step, the model-based algorithm was evaluated by controlling cardiac responses of two horses (horses 2 and 4) to a pre-defined trajectory. The model parameters were kept constant. On average, the error between the defined target trajectory in heart rate and the actual controlled heart rate ranged between 0.2 and 1.4 bpm for the whole target heart rate trajectory. During the steady-state part of the trajectory the average error was maximum 1.1 bpm. In the transient from one steady-state heart rate to another level, the error could increase on average up to 5 bpm. In the future, the combination of on-line measured bioresponses with real-time analysis can be used for adjusting the work load of the horse, during training, directly to the immediate needs of horse (welfare) and trainer (performance).
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Jezierski T., G. A. (2000). Changes in the horses heart rate during different levels of social isolation. Anim. Sci. Pap. Rep., 18(1), 33–41.
Abstract: Social isolation in horses may be regarded as a stress factor which implies welfare problems. The aim of the experiment was to examine the effect of different levels of transient social isolation and human presence on the heart rate (HR) in horses. Seven horses were used and the experiment was conducted in a tether-stable without boxes. The HR was recorded electronically, continuously for 40 min during the following test situations: all horses in the stable; experimenter approaches the tested horse, other horses being untied and leaving the stable; tested horse staying alone or in the company of one or two stable-mates; the experimenter attempts to calm the isolated horse; outdoor auditory stimuli from other horses. The HR was significantly higher during the whole period of isolation, and depended on how many horses were left as company for the one tested. The highest HR was observed while other horses were leaving the stable and during perception of outdoor auditory stimuli from others. When in the company of two stable mates, the HR was elevated only while other horses were leaving the stable and during auditory stimuli from outdoors. Human presence evoked a significant increase in HR, probably due to conditioning of horses (expecting to be untied and allowed to join the others), irrespectively whether the tested horse was left alone or with one or two stable-mates.
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Jezierski, T., Jaworski, Z., & Górecka, A. (1999). Effects of handling on behaviour and heart rate in Konik horses: comparison of stable and forest reared youngstock. Appl. Anim. Behav. Sci., 62(1), 1–11.
Abstract: Thirty foals and young Konik horses born in 3 consecutive years and reared up to weaning either in a forest reserve (R) or conventional stable (S) were compared with respect to behavioural reactions and heart rate (HR) during handling manipulations. The foals were randomly allocated within sex and rearing group to one of two handling treatments. Intensively handled (IH) foals received a 10-min handling, 5 days/week, beginning at the age of 2 weeks (S foals) or 10 months (R foals), and lasting up to the age of 24 months. During handling IH foals were haltered, touched, rubbed and their feet were picked up; non-handled (NH) foals were not handled except for routine or emergency veterinary care. The horses were tested at the age of approximately 6 months (S only) and 12, 18 and 24 months of age. In a test comprising catching the horse on a paddock, leading away from and towards the stable, picking up feet and being approached by an unfamiliar person, the horses' behaviour was scored and the HR was recorded telemetrically. The IH horses scored better as far as manageability behaviour is concerned (P<0.001) and demonstrated lower HR than the NH ones and the S horses scored better than R ones (P<0.001). Fillies demonstrated higher HR than colts (P=0.007). Youngstock of all groups tended to be less manageable at the age of 24 months than at 18 months. Differences between youngstock stemming from particular harems from the reserve seem to be related to differences in accidental contact with people visiting the forest reserve.
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Munsters, C. C. B. M., Visser, K. E. K., van den Broek, J., & Sloet van Oldruitenborgh-Oosterbaan, M. M. (2012). The influence of challenging objects and horse-rider matching on heart rate, heart rate variability and behavioural score in riding horses. The Veterinary Journal, 192(1), 75–80.
Abstract: A good horse-rider ‘match’ is important in the context of equine welfare. To quantify the influence of repetition and horse-rider matching on the stress of horses encountering challenging objects, 16 Warmblood horses were ridden in a test-setting on three occasions. On each occasion the horse was ridden by a different rider and was challenged by three objects (A–C). Heart rate (HR), heart rate variability (HRV) of horse and rider, and behaviour score (BS) of the horse were obtained for each object and as a total for each test. The horse-rider interaction was evaluated with each combination and assessed as ‘matching’ or ‘mismatching’, and the horses were categorised as ‘compliant’, ‘partly-compliant’ or ‘non-compliant’. Horses exhibited a decreased HR (P = 0.015) and a decreased BS (P = 0.004) within and across different tests. ‘Matching’ horse-rider combinations exhibited less stress as indicated by reduced HR (‘match’ 69 ± 10 vs. ‘mismatch’ 72 ± 9, P = 0.001) and BS (‘match’ 1.9 ± 1.1 vs. ‘mismatch’ 3.8 ± 1.4, P = 0.017) of the horse. ‘Compliant’ (68 ± 8, P < 0.001) and ‘partly-compliant’ (71 ± 9, P = 0.002) horses had significantly lower HR than ‘non-compliant’ (75 ± 9) animals. The findings of the study indicate that HR and BS measurements support a subjective ‘match’ diagnosis and HR measurement may be a valuable tool in assessing horse compliance.
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