International Journal of Equine Science

Dynamic Hematological Responses in Endurance Horses: Unraveling Blood Physiological Markers of Exercise Stress and Recovery

2024-06-11T04:49:47-06:00

This study aimed to investigate the effects of endurance exercise on erythrogram parameters and identify stress and inflammation markers that could serve as reliable indicators for assessing recovery in endurance horses. The study involved 26 Arabian endurance horses (4 stallions and 22 geldings) aged between 8 and 12 years, each completing a race (10 horses in 80 km, 10 horses in 120 km, and 6 horses in 160 km). Blood samples were collected at six different time points: at rest (T0), immediately after the race (T1), 3 hours after the race (T2), and 3, 7, and 14 days after the race (T3, T4, T5). The hemogram analyses included several hematological indices such as neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), monocyte-to-lymphocyte ratio (MLR), eosinophil-to-lymphocyte ratio (ELR), red blood cell distribution width-to-platelet ratio (RDW/PLT), hemoglobin-to-red blood cell distribution width ratio (Hb/RDW), hemoglobin-to-platelet ratio (Hb/PLT), systemic inflammation index (SII), systemic inflammatory response index (SIRI), leukocyte shift index (LSI), and adaptation intensity index of L. Harkavy (AI). The findings revealed that some indices, such as NLR, PLR, SII, SIRI, MLR, RDW/PLT, and LSI, were sensitive to acute physiological changes related to the endurance race. These indices showed significant variations immediately after the race, indicating a stress and inflammatory response. In contrast, the ELR and AI indices displayed delayed and more prolonged responses, suggesting their utility in monitoring the post-exercise recovery phase. Overall, this study offers insights into applying hematological markers to assess endurance horses' stress, inflammation, and recovery. These findings could contribute to improved training and recovery strategies, promoting the health and welfare of equine athletes during and after intense physical exertion. Further research is recommended to explore these indices in larger samples and other equine sports.

A Preliminary Assessment of Shade and Shelter Use in Paddock-Kept Horses in Australia: A Pilot Study

2024-06-26T04:59:28-06:00

There is increasing evidence to support the recommendation of providing horses with adequate shade, either natural or man-made, to safeguard their welfare. Weather conditions, particularly extreme temperatures, influence horses' shade-seeking behavior and ability to thermoregulate. However, there is limited research on other factors that may influence equine shade-seeking behavior. The aim of this study was to investigate the influence of weather conditions and shade type available on horses’ shade-seeking behavior in non-extreme conditions, i.e. not in the intensity of summer, using animal-based behavioral indicators. Shade-seeking behavior of 19 university-owned horses was observed over a period of six days. Horses were kept in groups (n = 7 to 12 individuals) in paddocks with free access to an artificial shelter (AS) and natural shade (NS). The location of each horse was recorded at hourly intervals during the day along with the time of day, ambient temperature, and prevailing weather conditions. Shade use was not related to the time of day, and horses spent most of their time in non-shade (85.5%), compared to natural shade (10.2%) and artificial shade (4.3%; H₂= 187.85, p < 0.0001). However, horses were more likely to seek artificial shade in foggy or cloudy conditions and natural shade when it was partly cloudy (Chi²₁₂= 30.14; p < 0.05). Horses preferred natural to artificial shade, spending 78% of their shade-time in natural shade. Although horses spent the majority of their time not in the shade in this study, it does not mean that shade is not important for the thermal comfort and wellbeing of the horse. Horses still displayed shade-seeking behavior during conditions not deemed extreme, for example, in fog and reduced visibility conditions. Further research could be beneficial to understanding shade-seeking behavior in horses in order to determine what constitutes acceptable shade provision to optimize horse welfare.

Temporal Trends in Equine Sperm Motility and Semen Volume: A Retrospective Analysis from a Single UK Breeding Facility

2024-08-05T04:31:27-06:00

The equine industry preferentially selects sires based on pedigree, performance, and conformation, with little concern given to fertility. Increasing evidence supports the theory of geographic-sensitive declines in a range of semen quality parameters, yet the horse is underrepresented within this field. Data presented here retrospectively investigates trends in semen quality from a population of stallions at a single UK breeding facility (from 2001 to 2020). Data on stallion sperm motility (10,686 ejaculates, 984 stallions) and semen volume (11,122 ejaculates, 1,030 stallions) were collected from records during the years 2020 and 2021. Data were analyzed as isolated variables in a linear mixed model (REML). Fixed effects included significant covariates (year of collection, age, and abstinence period). Random effects included stallion and sample numbers. Overall trends indicated that motility has declined over the past 20 years (p < 0.001; overall decline: 12.19%). Motility declined similarly in both prime and senescent stallions, confirming trends are not age-specific. Trends in volume (p < 0.001) varied over time but typically increased (5.70 mL overall; 0.28 mL annually). Results suggest stallions could be at risk of perturbed reproductive health and function in the future, with serious implications for the economic status of breeding stallions and the health and welfare of breeding stock.

Radiographic Texture of the Trabecular Bone in the Proximal Phalanx of Horses

2024-08-22T02:13:54-06:00

Trabecular bone is highly dynamic in response to external and internal stimuli, and changes in its structure can be quantified through fractal analysis. However, fractal analysis is still an incipient technique in equine research. This study aimed to evaluate the complexity, heterogeneity, and density of the trabecular bone of the proximal phalanx (P1) of healthy adult horses of different breeds and sexes by measuring the values of fractal dimension (FD), lacunarity, and bone area fraction (BA/TA) in 65 radiographic examinations of the metacarpophalangeal joint and evaluate the agreement between the BoneJ and FracLac plugins for measuring FD. Regions of interest of 50 × 50 pixels were manually selected on the trabecular bone in the proximal epiphysis of the P1. No differences were observed for FD, lacunarity, and BA/TA between horses of different breeds and sexes (p > 0.1). The BoneJ and FracLac plugins showed no agreement when measuring FD (p < 0.01). Therefore, the radiographic texture of the trabecular bone of the P1 in horses had no influence depending on the analyzed breed or sex. The FracLac plugin measured higher FD values, and hence standardization using the BoneJ plugin is recommended. Further studies are required to evaluate other breeds, age groups, and training levels.

A Preliminary Study on Feeding Straw to Horses and Its Effects on Equine Chewing and Consumption Rates

2024-09-01T04:35:09-06:00

Straw as a forage source has been investigated with regards to managing obese horses. However, its effect on chewing rate (CHR) and consumption rate (CR) lacks convincing evidence to encourage its inclusion. In this 2×7-day crossover study, the CHR (chews/5 mins) and CR (kg/hour) of eight horses were analyzed for differences in response to two diets: 50% oat straw, 50% haylage (S) and 100% haylage (CON). On Day 1, CR with S was lower compared to CON (p > 0.05), and by Day 7, this decrease was statistically significant (p = 0.018). CHR was lower on S on Day 1 than CON but higher on Day 7 (p > 0.05). The results suggest that oat straw provided at 50% of the forage ration slows consumption and alters chewing behavior in favor of managing obese horses. Adding oat straw to the forage diet can potentially improve the welfare of horses with low-energy requirements.

Unilateral-Dominant Lameness Induces Changes in Breakover Duration Symmetry in Equine Walk

2024-08-19T01:28:33-06:00

Lameness is widely regarded as the most prevalent problem affecting equines globally. Much is understood about the adjustment of upper body posture to reduce loading in an affected limb. However, the relationship between lameness and breakover duration, when the distal limb experiences high tensile stresses, remains an underinvestigated area. Thus, this study aimed to investigate breakover duration at walk in a cohort of horses, quantifying the effect of fore- and hindlimb lameness. It was hypothesized that lameness would induce an asymmetry between breakover durations of affected contralateral limb pairs. Breakover durations of sixteen horses (five sound and eleven lame, as presented by owners) were measured using data collected by hoof-mounted gyroscopes. Breakover durations of the limbs of contralateral pairs were compared, and paired Student's t-tests were used to determine whether differences were significant (p < 0.01). A high degree of symmetry was seen in breakover durations of sound horses, with a mean (SD) duration of 168(19)ms and a negligible mean absolute difference (6ms, p = 0.07). In lame horses, breakover durations of lame limbs (167(22)ms) were longer than those of contralateral limbs (146(23)ms, p < 0.001); and breakover durations of the ipsilateral (160(26)ms) and diagonal (162(24)ms) limbs were equivalent and comparable to those of sound limb pairs. These results indicate that where there is lameness present in a contralateral limb pair, there will be a breakdown in the symmetry of breakover duration, with the most severely affected limb having a significantly longer breakover duration than the contralateral. This pattern should be investigated in the future as a marker to indicate lameness.

Are We on the Same Page? A Review of Horse Training Approaches, Terminology Use, and Method Reporting within the Scientific Literature

2024-07-21T04:11:13-06:00

It is vital that the impact of different horse training approaches (TAs) is studied to ensure the methods employed are effective, ethical, and do not compromise equine welfare. While a range of TAs are referred to within the scientific literature, no research has explored whether the way these are applied, described, and reported is consistent across existing studies. This is problematic as differences in training application and method reporting may alter study outcomes, limit the potential for inter-study comparison, and impede effective scientific communication. A systematic search of the published literature from three online databases (Scopus, Web of Science, and PubMed) was used to identify studies that apply horse TAs within their methodology. A description of the training protocols was extracted from each paper and used to categorize the training approach(es) employed, identify their defining characteristics, and assess consistency within TA description. A total of 75 studies published between 1992 and 2021 were reviewed using a mapping review method, within which ten distinct TA categories were identified. Six of these aligned directly with the principles of learning theory; however, distinct differences in their application were identified. The four remaining categories were less clearly defined, with a wider range of terms used to describe them. Limited information provided within some methodologies would render accurate study replication impossible. This study highlights a need for more consistent and detailed reporting of horse TAs within the scientific literature, and subsequently, some initial recommendations to promote this have been made. This would facilitate communication between researchers and further enable comparisons to be made across studies, ultimately improving understanding of modern horse training practices and their welfare impact.