Search

Horse's stress responses have been reported during road transport in temperate but not tropical environments. Therefore, this study measured cortisol levels, heart rate (HR), and heart rate variability (HRV) in horses during medium-distance road transport with different truck conditions in a tropical environment. Six horses were repeatedly transported in either air-conditioned trucks with full (ATF) or space (ATS) loads or non-air-conditioned trucks with full (N-ATF) and space (N-ATS) loads. Blood cortisol was determined beforehand and 5, 30, and 90 minutes post-transport. HR and HRV were assessed pre-transport and at 15-minute intervals until 90 minutes post-transport. Cortisol levels increased significantly in N-ATS horses (but non-significantly in ATF, ATS, and N-ATF horses) at 5 minutes post-transport and returned to baseline by 30 minutes post-transport. Predominant parasympathetic nervous system (PNS) activity was observed during the first few hours and returned to baseline until the destination was reached. A recurrent, increased PNS activity was detected post-transport. Interaction effects of air condition-by-loading condition-by-time, air condition-by-time, and separate effects of air condition and time were observed on HR and various HRV variables during transport. A transient increase in beat-to-beat intervals, coinciding with decreased HR, was observed in ATF horses. The PNS index increased, corresponding to a decreased sympathetic nervous system index, in ATS horses during transport. We suggest that medium-distance road transport causes no stress for transport-experienced horses in a tropical environment. Air and loading conditions impacted hormonal and autonomic modulation, causing different responses in horses transported in differently conditioned trucks. [ABSTRACT FROM AUTHOR]

Simple Summary: The use of single-box housing for domestic horses is a matter of concern due to its potential negative effects on their social interaction and movement. Horses in tropical regions may also face challenges due to heat and humidity fluctuations affecting their thermal comfort and heat dissipation. This study sought to explore the stress responses in horses housed in different stable designs in a tropical savanna region, as little research has considered this topic. The results reveal correlations across stable designs between internal humidity, air temperature, ammonia levels, and heart rate variability (HRV) modulation in horses. We also observed distinct stress responses in horses in different stable designs. These findings suggest that daily changes in the internal environment, as well as stable design, play crucial roles in affecting horses' stress responses and overall well-being in tropical savanna regions. These results have important welfare implications for the management of horse housing in such environments. Single-confinement housing can pose welfare risks to domestic horses. This study investigated horses' stress responses when confined to single stalls in different stable designs in a tropical savanna region to address a gap in the literature. In total, 23 horses were assigned to a stable with a central corridor and solid external walls (A) (N = 8), a stable with one side corridor and solid external walls (B) (N = 6), or a stable with a central corridor and no solid external walls (C) (N = 9). Air velocity, relative humidity, air temperature, and noxious gases were measured inside the stables, and the heart rate and HRV of the horses were also determined. The relative humidity was lower in stable C than in stable A (p < 0.05), while the air temperature was higher in stable C than in stable B (p < 0.05) during the day. The airflow and ammonia levels were higher in stable C than in stables B and A (p < 0.01–0.0001). Overall, horses' HRV in stable A was lower than in those in stables B and C (p < 0.05–0.01). Horses in stable A tended to experience more stress than those in other stables. [ABSTRACT FROM AUTHOR]

Strenuous exercise in traditional polo matches creates enormous stress on horses. Hematological and physiological measures may vary across different field-play positions. This study aimed to investigate the effort intensity and the impact of exertion on hematology and heart rate variability (HRV) in polo ponies with different positions. Thirty-two ponies, divided equally into eight teams, were studied. Each comprises forwards (number 1), midfielders (numbers 2 and 3), and defenders (number 4). Team pairs played the first chukka in four low-goal polo matches. Percent maximum heart rate (%HRmax), indicating ponies' effort intensity, was classified into five zones, including zones 1 (<70%), 2 (70–80%), 3 (80–90%), 4 (90–95%) and 5 (>95%). Hematological and HRV parameters were determined before, immediately after, and at 30-minute intervals for 180 minutes after chukkas; HRV variables were also obtained during warm-up and exercise periods. Results indicated that the number two ponies spent more time in zone 4 (p < 0.05) but less in zone 2 (p < 0.01) than the number four ponies. Cortisol levels increased immediately and 30 minutes afterward (p < 0.0001 for both) and then returned to baseline 60–90 minutes after exertion. Other measures (Hct, Hb, RBC, WBC, neutrophils, and CK enzyme) increased immediately (p < 0.0001 for all) and lasted at least 180 minutes after exertion (p < 0.05–0.0001). HRV decreased during the chukka until approximately 90 minutes afterward (p < 0.05–0.0001). The stress index increased during the chukka and declined to baseline at 60 minutes in number 1–3 ponies but lasted 90 minutes in those at number four. Effort intensity distribution differed among field-play positions. Decreased HRV indicated reduced parasympathetic activity during exercise, extending to 90 minutes after exertion in polo ponies. Defenders seem to experience more stress than those in other positions. [ABSTRACT FROM AUTHOR]

Horses were provided full-time housing in unfamiliar vector-protected facilities during the African horse sickness (AHS) outbreak in Thailand. This study aimed to investigate the impact of this housing arrangement on the equine stress response. Nine healthy horses were housed in both a traditional barn and a vector-protected barn. Equine behavior and stress response data were collected in association with the housing environment and time of day. The mean behavioral score of horses housed in the vector-protected barn was lower at night than during the day. In addition, the horses' mean heart rate at night was lower than their heart rate during the day, irrespective of housing condition. Furthermore, although blood cortisol peaked at 6:00 AM and was lowest at 6:00 PM under both housing conditions, daily fluctuations in blood cortisol levels were correlated with changes in humidity and temperature in both environments. Finally, horses housed in the traditional barn exhibited earlier decreases in cortisol levels relative to the horses in the vector-protected barn. This result indicates that housing horses in vector-protected facilities may impose stress. [ABSTRACT FROM AUTHOR]

Background: The expressions of vitamin D receptor (VDR) and vitamin D‐metabolising enzymes (CYP27B1 and CYP24A1) in skeletal muscle have been reported. However, the regulation of this vitamin D system in horse skeletal muscle after high‐intensity exercise has not yet been elucidated. Objectives: To investigate the effect of high‐intensity exercise on the expression of vitamin D system‐related proteins in horse skeletal muscle and its associations with skeletal muscle stem cell (SMSC) activity and serum 25(OH)D level. Study design: Longitudinal study. Methods: Six healthy ponies (5 geldings, 1 mare; age 6.3 ± 2.2 years) were studied. Serum and muscle samples were taken from the jugular vein and gluteus medius respectively. Samples were collected at pre‐exercise, post‐exercise, 1 and 3 weeks after a single bout of high‐intensity exercise. Protein expression levels of VDR, CYP27B1, CYP24A1, OxPhos and Pax7 (SMSC marker) were determined using immunohistochemical analysis. Oxidative capacity and intramuscular glycogen content were evaluated using histochemical analysis. Blood biochemistry was analysed for lactate concentration and creatine kinase (CK), and 25(OH)D activity. Results: High‐intensity exercise significantly upregulated Pax7 and VDR protein expression, which correlated with significantly increased blood lactate and serum CK levels immediately post‐exercise. Serum 25(OH)D2 level correlated with CYP27B1 protein expression in skeletal muscle, and it reduced significantly immediately post‐exercise and at 1 and 3 weeks post‐exercise. However, CYP24A1 protein expression was unchanged throughout study periods. Main limitation: The healthy ponies could not represent a fit population of racehorses and eventers. Conclusions: The rapid increase in Pax7 and VDR protein expression along with serum CK level after high‐intensity exercise demonstrated an association between SMSC activity and activation of the vitamin D system in response to muscle injury in horses. Moreover, a decrease in CYP27B1 protein expression, correlated with a reduction in serum 25(OH)D2, may indicate a compromised vitamin D metabolism after high‐intensity exercise. [ABSTRACT FROM AUTHOR]

Single-confinement housing can pose welfare risks to domestic horses. This study investigated horses' stress responses when confined to single stalls in different stable designs in a tropical savanna region to address a gap in the literature. In total, 23 horses were assigned to a stable with a central corridor and solid external walls (A) (N = 8), a stable with one side corridor and solid external walls (B) (N = 6), or a stable with a central corridor and no solid external walls (C) (N = 9). Air velocity, relative humidity, air temperature, and noxious gases were measured inside the stables, and the heart rate and HRV of the horses were also determined. The relative humidity was lower in stable C than in stable A ( p < 0.05), while the air temperature was higher in stable C than in stable B ( p < 0.05) during the day. The airflow and ammonia levels were higher in stable C than in stables B and A ( p < 0.01-0.0001). Overall, horses' HRV in stable A was lower than in those in stables B and C ( p < 0.05-0.01). Horses in stable A tended to experience more stress than those in other stables.

Background: Underrun heels are among the most hoof imbalances, causing poor performance in hoses. Several corrective shoeing protocols have been performed, but the outcomes have yet to be consistent. In this study, we proposed an alternative trimming protocol for managing underrun heels: strategic palmar trimming before conventional shoeing. Therefore, the current study aimed to investigate the potential of strategic palmar trimming before conventional shoeing for managing hoof imbalance in horses with underrun heels., Methods: Eleven affected horses were divided into control (5 horses with 14 defective hooves) and experimental (6 horses with 16 defective hooves) groups. The experimental group underwent strategic palmar trimming before conventional shoeing, while the control horses received regular trimming before traditional shoeing. Dorsal hoof wall angle (DHWA)/heel angle (HA) ratios, heel-bulb distance, and six parallel lines indicating solar surface dimension were determined before, and after 5, 10, 15, 20, 25, and 30 weeks of the different trimming protocols. Palmar trimming distance was only measured in experimental horses., Results: A group-by-time interaction was observed for DHWA/HA ratios and solar surface dimension. Separate effects for group and time were observed in the heel-bulb distance. A modification in hoof conformation was detected at 25-30 weeks only in horses in the experimental group, including decreases in DHWA/HA ratio, heel-bulb distance, and palmar trimming distance, coinciding with an increase in palmar width of trimmed hooves., Conclusions: Different trimming protocols produced a different effect on hoof conformation. Therefore, tactical remedial trimming can potentially control poor hoof conformation in horses with underrun heels., Competing Interests: No competing interests were disclosed., (Copyright: © 2024 Poochipakorn C et al.)