Abstract: Based on cortisol release, a variety of situations to which domestic horses are exposed have been classified as stressors but studies on the stress during equestrian training are limited. In the present study, Warmblood stallions (n = 9) and mares (n = 7) were followed through a 9 respective 12-week initial training program in order to determine potentially stressful training steps. Salivary cortisol concentrations, beat-to-beat (RR) interval and heart rate variability (HRV) were determined. The HRV variables standard deviation of the RR interval (SDRR), RMSSD (root mean square of successive RR differences) and the geometric means standard deviation 1 (SD1) and 2 (SD2) were calculated. Nearly each training unit was associated with an increase in salivary cortisol concentrations (p < 0.01). Cortisol release varied between training units and occasionally was more pronounced in mares than in stallions (p < 0.05). The RR interval decreased slightly in response to lunging before mounting of the rider. A pronounced decrease occurred when the rider was mounting, but before the horse showed physical activity (p < 0.001). The HRV variables SDRR, RMSSD and SD1 decreased in response to training and lowest values were reached during mounting of a rider (p < 0.001). Thereafter RR interval and HRV variables increased again. In contrast, SD2 increased with the beginning of lunging (p < 0.05) and no changes in response to mounting were detectable. In conclusion, initial training is a stressor for horses. The most pronounced reaction occurred in response to mounting by a rider, a situation resembling a potentially lethal threat under natural conditions.

Abstract: The objective of this study was to compare the stress response of horses suffering from laminitis after short- and long-term treatment with the intent to evaluate power spectral analysis of heart rate variability (HRV) for pain monitoring. Data were collected from 19 horses with acute or chronic exacerbating laminitis without known primary disease before and after treatment with non-steroidal anti-inflammatory drugs (NSAID). Recordings were carried out the day after admission to the equine hospital. Measurements were repeated on day 7 of the treatment. The recorded parameters included a clinical orthopaedic index (OLPI: Obel-grade plus hoof tester score), frequency of weight-shifting between contralateral limbs, mean beat-to-beat interval (R-R) duration, standard deviation of continuous R-R intervals, low- (LF) and high-frequency (HF) components of HRV, sympatho-vagal balance (LF/HF), and plasma concentration of cortisol, adrenalin and noradrenalin. The LF represents mainly sympathetic influences on the heart whereas HF is mediated by the parasympathetic tone. Weight-shifting and OLPI decreased significantly with treatment. The LF normalized units (n.u.) decreased after NSAID from 60.41 +/- 21.42 to 51.12 +/- 19.81 and was 49.33 +/- 22.64 on day 7, whereas HF n.u. increased from 35.07 +/- 20.02 to 43.14 +/- 18.30 and was 45.98 +/- 23.00 on day 7. Hormone levels showed no tendency to change with treatment. The OLPI was only correlated with LF/HF, LF and HF (R = 0.57, 0.55 and -0.54 respectively). Significant negative correlations existed between HFn.u. and weight-shifting frequency (R = -0.37), HFn.u. and adrenalin (R = -0.47), and HFn.u. and noradrenalin (R = 0.33). The LFn.u. only correlated positively with adrenalin. Cortisol levels were poorly associated with the other parameters. Determination of the sympatho-vagal influences on cardiac function may offer complementary information for reliable assessment of pain and may represent a valuable alternative method to catecholamine measurements.

Abstract: In various species, sex, hormonal treatments and oestrous-cycle stage have been shown to affect the animal's response in behavioural tests. Few such studies have been performed in the horse. The main aim of the present study was to investigate whether oestrous-cycle stage affects mares' response to a novel object test and isolation test and, in part, to study whether mares, assumed to suffer from oestrous-related behavioural problems, respond differently in these tests when compared with controls. Twelve mares were tested twice, in oestrus and dioestrus, in a crossover design. Seven behavioural and two heart rate variables were measured for the novel object test and two heart rate variables for the isolation test. Oestrous-cycle stage and whether a mare was classified as a 'problem' mare did not affect the mare's response. However, test order, i.e. the cycle stage a mare was tested in first, affected its reaction. This effect could partly be explained by significant differences between test occasions 1 and 2 in three behavioural variables and one heart rate variable (p < 0.05) in the novel object test. The mares explored the novel object more and had a higher mean heart rate in the first test. Exploring the novel object more could largely be attributed to those mares tested in dioestrus first, perhaps indicating that the mares in oestrus were less receptive to the novel object. The reason for the differences between test occasions could be an effect of learning or habituation.

Abstract: Ziel: Überprüfung der Tiergerechtheit von in der Bauweise unterschiedlichen
Futterabrufstationen für Pferde in Gruppenhaltung anhand ethologischer
und physiologischer Parameter. Material und Methoden: In 32
Offenlaufställen (452 Pferde) mit computergesteuerten Abrufstationen
für Kraftfutter und Heu erfolgten kontinuierliche Direktbeobachtungen
für je einen 24-Stunden-Tag (Tortenstückverfahren). Erfasst wurden: Aufenthaltsdauer,
Besuchshäufigkeit, Droh- und Meideverhalten im Fütterungsbereich,
Blockaden sowie Herzfrequenz und Integumentverletzungen.
Ergebnisse: Eine Durchlaufstation reduzierte die Zahl der Auseinandersetzungen
im Fütterungsbereich signifikant. Ansonsten erhöhten die
für das fressende Pferd tiergerechten Varianten (Fressstand mit Eingangssperre,
ohne Austreibehilfe) Besuchshäufigkeit und Aufenthaltsdauer und
steigerten somit auch die Anzahl an Drohgesten je Tier und Tag. Insgesamt
betrachtet kann jedoch die Anzahl an sozionegativen Interaktionen
im Fütterungsbereich der Abrufstationen als relativ gering eingestuft
werden. Die Herzfrequenz lag im Warteareal bei den meisten Pferden im
physiologischen Bereich (45,1 ± 12,42 Schläge/min), erhöhte sich jedoch
in der Abrufstation um ca. 20 Schläge/min. Einige Tiere zeigten möglicherweise
stressbedingt kurzfristig auffallend hohe Werte (&#8805; 100 Schläge/
min). Integumentverletzungen im Zusammenhang mit dem Fütterungssystem
traten nicht auf. Der wichtigste Einflussfaktor auf die Untersuchungskriterien
war der Betrieb (Fläche, Konzeption, Management).
Schlussfolgerung: Durchlaufstationen sind pferdegerechter als Rücklaufstationen.
Nicht tiergerecht sind Stationen mit stromführender Austreibehilfe.
Weitere bauliche Unterschiede der derzeitigen Futterabrufstationen
dürften eher von untergeordneter Bedeutung sein, vor allem da
Flächengebot und Konzeption der Offenstallanlage sowie das Management
die überprüften Kriterien zur Tiergerechtheit maßgeblich beeinflussen.
Untersuchungen zur Abklärung der Ursache für die vereinzelt aufgetretenen
sehr hohen Herzfrequenzwerte sollten durchgeführt werden.
Objective: Comparison with regard to animal welfare of different automatic
feeding systems for hay and concentrate in group housing systems
for horses using parameters of ethology and physiology. Material and
methods: Parameters of research comprised: duration of stay, frequency
of visit, threatening behaviour with and without risk of injury, and avoiding
behaviour as well as heart rate and injuries of the integument. 452
horses were observed at the feeding area of 32 run-out-sheds. Every group
of horses was continuously observed following the pie chart system for
24 hours. Results: The “walk-through” station significantly reduced the
number of conflicts in the feeding area, whereas those systems which are
appropriate for the feeding horses (feeding station with access barrier and
without stimulation device by electric shock) led to a higher frequency of
visits and a longer duration of stay resulting in more threatening gestures.
However, the number of negative interactions in the feeding area of the
feeding systems can all together be classified as relatively insignificant.
The heart rate was within the physiological range (45.1 ± 12.42 beats/min)
in the waiting area, but increased by approximately 20 beats/min on average
within the feeding station. Some horses showed a very high heart rate
(&#8805; 100 beats/min) while entering the feeding station, possibly stress-related.
There were no injuries of the integument associated with the feeding
systems. The most important factor of the observation criteria was the
individual group housing system with its different dimensions, conception
and management. Conclusion: “Walk-through” stations are better than
”walk-back” stations with regard to animal welfare. Likewise, automatic
feeding stations with a current-carrying stimulation device are not supportive
of good welfare. The other differences between the constructions
of feeding stations of present systems are probably of less importance, particularly
as it was shown that the stable (management, stable area, conception)
had a significant influence on the surveyed parameters. Investigations
to obtain information on the cause for the sporadic occurrence of
very high heart rate values should be undertaken.]

Abstract: It is widely accepted that transport is stressful for horses, but only a few studies are available involving horses that are transported regularly and are accustomed to transport. We determined salivary cortisol immunoreactivity (IR), fecal cortisol metabolites, beat-to-beat (RR) interval, and heart rate variability (HRV) in transport-experienced horses (N = 7) in response to a 2-d outbound road transport over 1370 km and 2-d return transport 8 d later. Salivary cortisol IR was low until 60 min before transport but had increased (P < 0.05) 30 min before loading. Transport caused a further marked increase (P < 0.001), but the response tended to decrease with each day of transport. Concentrations of fecal cortisol metabolites increased on the second day of both outbound and return transports and reached a maximum the following day (P < 0.001). During the first 90 min on Day 1 of outbound transport, mean RR interval decreased (P < 0.001). Standard deviations of RR interval (SDRR) decreased transiently (P < 0.01). The root mean square of successive RR differences (RMSSD) decreased at the beginning of the outbound and return transports (P < 0.01), reflecting reduced parasympathetic tone. On the first day of both outbound and return transports, a transient rise in geometric HRV variable standard deviation 2 (SD2) occurred (P < 0.01), indicating increased sympathetic activity. In conclusion, transport of experienced horses leads to increased cortisol release and changes in heart rate and HRV, which is indicative of stress. The degree of these changes tended to be most pronounced on the first day of both outbound and return transport.