A pilot study investigating the relationship between perceived and actual workload and estimated energy intake in riding centre horses

Abstract

Feeding regimens for horses are usually based on perceived workload (PW) together with body condition. This can lead to inappropriate energy intake and, in particular, excess weight. Therefore, a more detailed understanding of the factors influencing individual energy needs under practical field conditions would be valuable. The purpose of this study was to evaluate to what extent the variations in actual versus PW may influence the estimated energy intake required to maintain body weight (BW) in individual animals. Eight mature, experienced riding school horses, chosen at random and maintaining a constant BW, were observed in standard flat work lessons with four different instructors at an equine training college. Heart rate (HR) and the structure of the lessons were recorded. Relative workload (RW) was determined for each horse by dividing its average HR per lesson by its estimated maximum HR (HR max ). PW was estimated by each instructor for each horse using a scale of 1-5. One-way ANOVA and t-test were used to determine the differences and Spearman's and Pearson's correlations were used to determine the correlations. The mean estimated RW was 39.1% of the estimated HR max (^5.7%) and was not significantly different between instructors (P . 0.05). Rider weight as a percentage of BW showed a weak but statistically significant positive correlation with mean HR (r 2 ¼ 0.14, P , 0.05). Estimated energy intake was negatively correlated with BCS (r 2 ¼ 0.65, P , 0.001) and differed significantly (P , 0.05) between light (BW ¼ 455-532 kg) horses (mean 0.18^0.04 MJ kg 21 BW) and heavy (BW ¼ 622-660 kg) horses (mean 0.15^0.03 MJ kg 21 BW). No difference was found in estimated energy intake between different workloads (flat work only or flat work and jumping) (P . 0.05). When BW was compared with estimated energy intake, no relation was found either (P . 0.05). These results suggest that the amount of energy needed to maintain BW in individual horses cannot necessarily be estimated simply on the basis of the intensity and the duration of structured exercise. Other factors including age, individual digestive and metabolic efficiency, body condition and possibly the energy utilized through non-structured activity (e.g. box walking) may need to be taken into account.

Comparison of physiological demands in Warmblood show jumping horses over a standardized 1.10 m jumping course versus a standardized exercise test on a track

“…However, there were many differences between the two studies, primarily the use of riding-school horses versus performance show jumpers (present study). Although riding-school horses are exercised frequently, the workload tends to be low [24,25]. The average heart rate over fences was in agreement with the mean heart rate range previously reported by Art et al during an official 1.50 m championship competition [2].…”

Estimation of the workload in horses during an eventing competition

“…This implies that other factors must have influenced the HR values. Indeed, even though the determination of HR during exercise provides an objective tool for estimating workload, for values under 120-140 bpm factors such as the level of horse excitement may influence the relationship between work intensity and HR (Dekker et al, 2007). In our study, the IL group was composed of non professional young riders and inexperienced horses, which could confound observations due to nervousness and lack of experience and may account for the large standard deviation recorded during the WU phase.…”

“…duration, distance and size of jumps) Moreover, since dressage and show-jumping tests were performed on the same day of the competition (day 1), it is necessary to sum the theoretical EEs for both tests; this leads to a value of energy expenditure in the 'intense work' range for the first day of competition as well as for the second day when the cross country test is performed. Energy supply is very important in sport horses (Dekker et al, 2007) and although the estimation of EE by speed or HR is not precise, it provides the most objective and easy tool for estimating workload in horses.…”

“…An adequate fitness level is necessary, especially in the case of high level competitions, in order to avoid accidents that could represent a source of dispute from the welfare point of view. The measurement of heart rate (HR) during exercise has been shown to be an objective tool for estimating workload in horses (Dekker et al, 2007). HR varies according to metabolic demands and can thus be considered a gauge of cardiovascular, metabolic, muscular and locomotor variables.…”

An investigation into the daily level of voluntary activity of stabled riding school horses

“…Various intrinsic and extrinsic factors have the potential to affect the digestible energy (DE) requirements of an individual horse being exercised including the horse's body weight (BW) and age plus any individual absorptive and metabolic factors, stage of training and workload, ability and weight of the rider, as well as environment and terrain (Anon, 2007;Harris, 1997;Hintz and Cymbaluk, 1994). However, it has been suggested that the small individual differences in workload between individuals of a similar bodyweight , age and fitness undertaking similar types of structured exercise under the same environmental conditions cannot always explain the variability in estimated DE intake required to maintain a constant BW (Dekker et al, 2007;Dekker, 2009). Individual differences in absorptive capacity or metabolic efficiency are a possible explanation (Anon, 2007), but other less obvious differences may exist between individuals including the amount of non-structured exercise they undertake.…”