Ageing draft and trotter horses by their dentition

La Tène Horse Remains from Alba Iulia CX 143 Complex: A Whole Story to Tell

The present paper deals with the archaeozoological investigation carried out on a horse skeleton discovered in a Late Iron Age La Tène tomb (coded CX 143) in Alba Iulia, Romania. The paper presents all the results of the investigation, with a description of finds, adding a detailed assessment of the dentition with some interesting conclusions on the usage of a horse bit and the possible consequences of this use. The morphological features of the horse indicate a 7-8-year-old male individual, with a recalculated height of 1200-1300 mm. What is also stressed in the investigated sample is the lack of the characteristic pathological lesions typical for horseback riding but showing distinctive elements of bit wear. A comparative perspective over the few findings from the same period is provided to ensure the framing of the identified individual into the much larger historical context.

A Retrospective Study on the Status of Working Equids Admitted to an Equine Clinic in Cairo: Disease Prevalence and Associations between Physical Parameters and Outcome

Working equids are often used to exhaustion, living and dying in conditions below minimal welfare standards. Due to their poor welfare status, euthanasia should be considered in certain conditions. The study aimed to describe the population and the disease frequency of the working equids admitted at an equine clinic in Cairo (i.e., Egypt Equine Aid (EEA)) from 2019 to 2022 and identify possible associations between physical parameters at admission and the outcome. Records of 1360 equids admitted at EEA were reviewed. The majority of the admitted equids were horses (65.6%), followed by donkeys (33%), in particular stallions (68.7%), from 1 to 15 years old (74.8%). Hospitalisation was mainly due to wounds (28.9%), orthopaedic problems (27.4%), colic (8.5%), or infectious diseases (7.4%). The majority of the equids were discharged, but 5.1% died on their own, without human intervention, and 23% were euthanised. Text mining revealed the anamnesis's most frequent words were 'accident', 'lameness', and 'wound'. In addition, owners sometimes reported using inappropriate remedies (e.g., firing) before hospitalisation. Multivariable ordinal regression analysis performed between physical parameters and the outcome (ordered based on severity: discharged, euthanasia, and dead) revealed that sex (male vs. female: OR = 1.33; p < 0.05), colour of the mucous membrane (pathological vs. physiological: OR = 1.72; p < 0.01), and capillary refill time (pathological vs. physiological: OR = 1.42; p = 0.02) increased the likelihood of a non-survival outcome. In conclusion, early euthanasia should be considered for these equids, to minimise prolonged suffering. Moreover, owners' education is recommended to guarantee minimal welfare standards to the working equids.

A Retrospective Observational Cohort Study on the Expiration of Maxillary Cheek Teeth Infundibula in 217 Horses

The determination of a horse's age by its dentition is a technique that has been employed by horse owners and professionals since at least 600 BC. While aging teeth based on incisor wear patterns is common, wear patterns in the cheek teeth may also be useful. As horses continue to live longer, we routinely examine horses into their 20's and 30's, and it is becoming more common to observe aging changes in the cheek teeth. To our knowledge, this study is the first to use easily obtained clinical observation of the expiration of cheek teeth infundibula to age horses of advanced ages (16 to 35 years). The results of this study indicate that the attrition of infundibula is likely due to the combined effects of eruption time, length of the tooth or infundibulum, forces placed on the tooth or infundibulum, and the presence of enamel or cemental hypoplasia. With additional prospective studies, the use of cheek tooth infundibular expiration may become a useful tool to determine the age of horses in the field.

Age estimation of Arabian mares by incisors morphometry and dentition changes

Accurate estimation of a horse's age based on the condition of the tooth status is necessary as a scientific and artistic technique, which has not been performed so far in pure Arabian horses of Khuzestan (southern west of Iran). This study aimed to investigate the age-dependent changes in the morphology and morphometry of the incisors in Arabian mares of Khuzestan to estimate age and to compare the estimated dental age and actual age. In this study, 78 Arabian mares of Khuzestan were examined in several equestrian clubs. Then, images were taken with a digital camera from the vestibular and occlusal surfaces of the lower incisors. Parameters of deciduous and permanent teeth eruption and their number, occlusal surface changes in the lower incisors including appearance and disappearance of the cup, enamel spot, dental star and appearance, and changes of Galvayne's groove in the upper corner incisor were investigated. Comparison of the clinical crown length of incisors in each group showed that first, second and third incisors (I_1, I_2, and I₃) had the maximum to minimum crown length, respectively. The correlation between actual age and clinical crown length was strong in I₁ (r = 0.73, p ≤ 0.001), I₂ (r = 0.8, p ≤ 0.001), and I₃ (r = 0.81, p ≤ 0.001) in the Arabian mares of Khuzestan. The correlation of estimated dental age with actual age in the Arabian mares of Khuzestan was very strong (r = 0.992, p ≤ 0.001). Therefore, the dental age estimation in the Arabian mares of Khuzestan appears to be very close to the actual age of the animal.

Computed Tomography (CT)-Assisted 3D Cephalometry in Horses: Interincisal Angulation of Clinical Crowns

The angle encompassed between opposing incisors in horses is assumed to decline with age. Previous studies merely consider the overall profile view of clinical crowns presuming a generalized angle, neglecting potential tooth position-dependent differences. Cephalometric measurements from 3D computed tomographic thick-slab reconstructions of single incisors within a global reference frame were used to determine clinical crown interincisal angulation (IIA) of 48 horses. Based on predefined dentoalveolar landmarks, IIA was defined as the angle enclosed by the respective labial axis of the clinical crown (LACC). A measurement repeatability analysis was conducted including a comparison of third incisor teeth IIA with data obtained by cephalometric implementation of previously described landmarks for third incisor teeth (lingual/palatal border). The age-related angle course and differences between tooth positions were investigated considering LACCs of permanent incisors. Determining IIA by LACCs exhibited a high level of reproducibility applying for all tooth positions (mean coefficient of variation = 0.65 %; mean SD ± 0.89°). The comparison method for third incisor teeth revealed two times higher mean dispersion of repeated measurements, P = 0.017. A non-linear model slightly increased predictability of angular changes over time as against linearity assumption. The angle decline was more distinctive in younger horses and appears to approach a final value in older ones. Third incisor teeth exhibited significantly higher angle decline compared to first and second incisor teeth, P < 0.0001. According to the results, age determination of horses using clinical crown IIA is not recommended. Rather, 3D cephalometry may provide a promising tool to determine interdental and dentofacial angles of distinct tooth positions in health and disease.

The Frequency of Errors in Determining Age Based on Selected Features of the Incisors of Icelandic Horses

The structure and changes occurring to horses' teeth during ontogeny are not only used to assess the degree of somatic maturity but also the development of universal patterns and is therefore used to determine the age of horses. Research shows that methods of assessing the age of horses based on the appearance of teeth tend to suffer from relatively large errors. This is probably influenced by the results of intensive selection and being kept in living conditions that differ substantially from their natural environment. This study aimed to assess the suitability of selected features of the incisors to determine the age of Icelandic horses. One hundred and twenty-six Icelandic horses (78 mares and 48 stallions) of different ages (range: 0-24 years; groups: 0-2 years, >2-5 years, >5-11 years, and >11 years) were examined by an experienced horse person who was blinded to the actual age of the horse and did not know which age group horses were in. Age was determined by the inspection of each horse's teeth and was compared to the actual age of the horse recorded in the breeding documentation, and the percentage of mistakes made regarding the age group was calculated. The estimated age did not match the real age in 36.5% of the horses. The age was more often underestimated (19.0%) by, on average, 0.9 ± 1.0 years than overestimated (17.5%) by, on average, 1.3 ± 1.4 years. Within age groups, the least number of errors in determining age were made in young horses aged 0-2 years, when the eruption and growing of the deciduous incisors and the disappearance of the cups was considered. The average percentage of errors in this group (2.1%) was significantly lower (p < 0.01) than for older horses, whose age was estimated based on the exchange of deciduous to permanent teeth (55.8%), disappearance of the cups (68.0%), and shape changes on the grinding surface (40.0%). Significantly more frequent underestimation of age based on replacing deciduous for permanent incisors and significantly more frequent overestimation of age on the basis of the disappearance of the cup may indicate that Icelandic horses up to 5 years of age are characterized by a slower rate of growth than horses of other breeds, especially warmblood horses. These results suggest that patterns used to determine the real age of horses based on changes occurring on the incisors should be modified in order to consider the specificity of the course of growth and maturation processes of horses of various types and breeds.

Use of crown height of the maxillary first molar tooth to approximate the age of horses

OBJECTIVE To identify whether age, sex, or breed is associated with crown height of the left and right maxillary first molar tooth (M1) measured on CT images, to develop a mathematical model to determine age of horses by use of M1 crown height, and to determine the correlation between M1 crown height measured on radiographic and CT images. SAMPLE CT (n = 735) and radiographic images (35) of the heads of horses. PROCEDURES Crown height of left and right M1 was digitally measured on axial CT views. Height was measured on a lateral radiographic image when available. Linear regression analysis was used to identify factors associated with crown height. Half the data set was subsequently used to generate a regression model to predict age on the basis of M1 crown height, and the other half was used to validate accuracy of the predictions. RESULTS M1 crown height decreased with increasing age, but the rate of decrease slowed with increasing age. Height also differed by sex and breed. The model most accurately reflected age of horses < 10 years old, although age was overestimated by a mean of 0.1 years. The correlation between radiographic and CT crown height of M1 was 0.91; the mean for radiographic measurements was 2.5 mm greater than for CT measurements. CONCLUSIONS AND CLINICAL RELEVANCE M1 crown height can be used to predict age of horses. Results for CT images correlated well with those for radiographic images. Studies are needed to develop a comparable model with results for radiographic images.

Colic in a working horse population in Egypt: Prevalence and risk factors

REASONS FOR PERFORMING STUDY

Colic is an important health problem in managed horse populations. Currently, there is limited information about colic prevalence and risk factors for colic in working horse populations.

OBJECTIVES

To determine the prevalence of, and risk factors for, colic in a working horse population in Egypt and to describe management practices in this working horse population.

STUDY DESIGN

Cross-sectional survey.

METHODS

Owners of 350 working horses were interviewed. Data about their horses, management and colic episodes in the preceding 12 months were collected. Dental examination was conducted on 342 horses and blood samples (n = 100) were collected for immunodiagnosis of tapeworm (Anoplocephala perfoliata) infection. Multivariable logistic regression analysis was used to identify risk factors for a history of colic in the preceding 12 months.

RESULTS

The 12-month prevalence of colic was 54.6%. Severe and moderate tapeworm infection intensity was identified in 3% and 26% of horses tested, respectively. Horses that had severe dental disease (odds ratio [OR] 6.8, 95% confidence interval [CI] 1.9-24.3, P<0.001), that displayed stereotypic behaviour (OR 2.0, 95% CI 1.15-3.5, P = 0.013), were fed ground corn during the 'dry season' (OR 1.65, 95% CI 1.03-2.6, P = 0.035) or that had received an anthelmintic in the previous 6 months (OR 2.1, 95% CI 1.3-3.3, P = 0.003) were more likely to have a history of colic in the preceding 12 months. Horses fed on rice bran during the 'green season' (OR 0.47, 95% CI 0.26-0.9, P = 0.015) and that displayed geophagia/coprophagia (OR 0.19, 95% CI 0.05-0.73, P = 0.001) were less likely to have a history of colic.

CONCLUSIONS

Colic is common in this working horse population and this study has identified factors associated with altered likelihood of colic. The study provides important information that may be used to inform future prospective studies investigating colic in working horse populations and to assist development of preventive healthcare strategies. The Summary is available in Chinese - see Supporting information.

Usefulness of Selected Incisor Characteristics for Determining the Age of Hucul Horses

The aim of this study was to assess the suitability of selected characteristics of incisors for age determination in Hucul horses. The study included 173 Hucul horses (137 mares, 28 stallions and 8 geldings) from one day to 27 years of age. Breeding documentation was used to determine the actual age of the horses, which were then divided into age groups. Each group of horses was assigned a specific incisor characteristic to help identify their age. Selected incisor characteristics were used to evaluate the age of the horses according to the method reported by Pruski (2007) and the results were compared with the actual age, indicating the percentage of errors made. It was found that most errors were made in the case of horses over 11 years old, when assessing the changing shape of the occlusal surface of incisors (Table 1). In this group the percentage of errors was significantly higher (P≤0.01) than that found for horses from the first three youngest age groups, in which the eruption time of deciduous incisors, the disappearance of cups on deciduous incisors and the eruption time of permanent incisors were taken into account. Compared to the above traits, errors were made significantly more often (P≤0.01) when age was determined based on the disappearance of permanent incisors, in a group of horses aged between 6 and 11 years. The eruption time of deciduous incisors and permanent incisors were the traits which enabled the most accurate determination of the horses' age. The results obtained suggest that age determination based on dentition is not accurate enough and can only play a subsidiary role, for example when no breeding records are available.

Comparison of the microhardness of enamel, primary and regular secondary dentine of the incisors of donkeys and horses

The microhardness of the enamel, primary dentine and regular secondary dentine of seven donkey and six horse incisors was determined with a Knoop indenter at the subocclusal and mid-tooth level. The mean microhardnesses of the donkey incisor enamel, primary dentine and secondary dentine were 264.6 63.00 and 53.6 Knoop Hardness Number, respectively. There was no significant difference between the microhardness of the enamel and primary dentine on the incisors of the donkeys and horses, but the microhardness of the regular secondary dentine of the donkeys' incisors at the mid-tooth level was slightly but significantly less than that of the horses. There was also a difference in the microhardness of the secondary dentine between the subocclusal and mid-tooth levels in both donkey and horse incisors.

Equine dental advances

The reintroduction and development of safe motorized instruments, the increased availability of continuing education, and the understanding and implementation of appropriate procedures allow practitioners to provide better dental care. Veterinarians realize that sedation, analgesia, a full-mouth speculum, and proper instrumentation are necessary to provide these services. Continued instrument design, future research, and new treatment and prophylactic protocols should have a positive impact on the future of equine dental health. New and rediscovered procedures for equilibrating equine occlusion are allowing horses to masticate more efficiently, carry a bit more comfortably, and experience improved performance. The horse, the horse owner, and the veterinary profession all benefit from providing complete equine dental care.

A study of the ultrastructure and staining characteristics of the 'dental star' of equine incisors

The objective of this study was to examine the diameter, extent, orientation and contents of dentinal tubules in order to validate the hypothesis of pigment penetration into the dental star of equine incisival occlusal surfaces. The time of appearance and the configuration of the dental star on the incisival occlusal surface are macroscopically visible features that, along with other more reliable parameters, are used for the determination of horses' age. Although dental stars are an integral part of the equine incisor occlusive surface, the exact nature and microstructure of the dental star are poorly documented. Therefore, equine incisor dentine was examined macroscopically and by scanning electron microscopy to elucidate numerical density, diameter and 3-dimensional organisation of the dentinal tubules in the dental star. The dental star is surrounded by primary dentine and consists of a central core of tertiary dentine, an intermediate ring of pale secondary dentine and a peripheral rim of darker, yellowish-brown secondary dentine. The central core of tertiary dentine contains relatively few dentinal tubules (<8000/mm2) that have small diameters (mean +/- s.d. 1.67 +/- 034 microm) and are arranged in an irregular pattern. The surrounding pale ring of secondary dentine comprises manifestly more and wider tubules that lie almost parallel to the occlusal surface. The dark peripheral rim of the dental star contains high numbers of tubules (28,000-58,000/mm2) that have wide luminal diameters (mean +/- s.d. 3.09 +/- 0.31 microm) and open perpendicular to the occlusal surface. In contrast, the primary dentine surrounding the dental star is made up by a lower number of dentinal tubules (<25,000/mm2). The tubules of primary dentine, which are initially mean +/- s.d. 5.15 +/- 0.80 microm wide, are narrowed by circumferential deposits of peritubular dentine and are obliquely exposed at the occlusal surface. From these observations, it was concluded that the regional differences in numerical density, diameter and spatial orientation of the dentinal tubules may influence the penetration of food pigments into the equine occlusal surface and result in the particular staining of the dental star.

Dental wear in horses in relation to the microhardness of enamel and dentine

The microhardness of enamel, primary dentine and secondary dentine was determined in the incisor teeth of 39 horses of three different breeds, trotter horses, Belgian draft horses and Arab horses. Using a microhardness tester fitted with a Knoop diamond indenter, the overall Knoop Hardness Number was determined for each tissue, and the influence of breed and age on the hardness were evaluated. Enamel and secondary dentine were significantly harder in Arab horses than in trotters and Belgian draft horses, but there were no significant differences between draft horses and trotter horses in the hardness of their enamel and dentine.

Dental embryology, anatomy, development, and aging

Equine practitioners should be knowledgeable of dental anatomy and development to enhance their skill of age estimation of horses. The permanent teeth of horses are continually undergoing changes in shape and appearance. These changes may be used to suggest a reasonable age range for a horse.

Dental disease in geriatric horses

The dental management of geriatric horses can be a rewarding challenge to the practitioner. Owners become dissatisfied when their expectations are unrealistic. Consequently, communication between the owner and the practitioner is essential prior to the start of any dental procedure in a geriatric horse. Owners often expect the practitioner to correct what has been neglected for years. It is critical that the owner understand the possible complications associated with dental procedures and that some procedures (e.g., trephination) may necessitate protracted care. Often, when a tooth has been removed, there is a need for more frequent masticatory examinations to curtail any potential problems (i.e., development of step mouth). The owner needs to be aware of the extra dental maintenance costs that must be included in the upkeep of the horse.

Ageing Arab horses by their dentition

The dentition of 170 Arab horses of known ages was examined and compared with the dental characteristics of trotter horses and Belgian draft horses of the same ages. The results indicated that inaccuracies in the determination of the age of horses by their dentition may result, at least partly, from differences between the breeds of horse involved because there were some major differences between the three breeds examined. These differences increased as the horses' true age increased. In general, the rate of dental wear was slower in the Arab horses than in trotter horses and Belgian draft horses.