Comparative study of dental age estimation methods against known chronological age in Nigerian local horses.

Overview

• This study compares six dental age estimation methods to determine which most accurately estimate the age of Nigerian local horses compared to their known chronological ages.
• Findings highlight the angle of incidence and eruption pattern methods as the most reliable for this population, offering guidance for veterinary practice and horse management in Nigeria.

Background and Purpose

• Dental age estimation in horses is crucial for:
• Ensuring appropriate healthcare
• Improving breeding programs
• Supporting welfare management
• Prior to this study, there was limited information about which dental aging methods are best suited for Nigerian local horses.
• The study aimed to evaluate and compare six different dental age estimation techniques against the known chronological ages of Nigerian local horses to identify the most accurate method(s).

Study Design and Methods

• A cross-sectional study was conducted involving 180 Nigerian local horses from Ibadan, Nigeria.
• Six dental age estimation methods were tested:
• Eruption patterns
• Grinding surface shape
• Presence and disappearance of cups
• Dental stars
• Angle of incidence of the teeth
• Galvayne’s groove
• Three veterinarians, blinded to the horses’ chronological ages, applied the six methods independently in groups of 30 horses each.
• Data was analyzed using statistical tests including:
• t-tests to assess differences between estimated and actual ages
• Pearson correlation coefficients to measure how closely estimations aligned with chronological age
• Bland-Altman plots to evaluate agreement and variation in estimates

Key Findings

• No significant difference was observed between estimated ages from any of the methods and the actual known ages (p > 0.05), indicating general validity of all methods.
• The angle of incidence method:
• Had the closest alignment with known ages, averaging 11.9 ± 5.4 years.
• Showed the highest correlation with chronological age (r = 0.988, p < 0.001), indicating outstanding accuracy.
• Better suited for a broad age range, particularly horses aged 5 to 30 years.
• However, it provides age estimates in broader categories rather than exact years.
• The eruption pattern method:
• Showed the smallest variation in age estimations (range of agreement: 2.3 years), demonstrating high precision.
• Most effective for younger horses aged between 3 and 5 years.
• Grinding surface and dental stars methods also demonstrated strong correlations with known ages (r = 0.955, p < 0.001).
• The Galvayne’s groove method:
• Exhibited the largest variability in age estimation (range of agreement: 9.9 years), making it less reliable for Nigerian local horses.

Implications and Recommendations

• For veterinarians and horse owners in Nigeria, the study suggests prioritizing:
• The angle of incidence method for overall age determination in mature horses.
• The eruption pattern method for more precise age estimates in younger horses.
• Care should be taken when using the Galvayne’s groove method due to considerable variability in age estimates.
• Accurate dental aging is important for informed decisions regarding:
• Healthcare and treatment plans
• Breeding suitability
• General welfare and management of Nigerian local horses

Conclusion

• The study identifies the angle of incidence method as the most correlated and reliable for dental age estimation in Nigerian local horses aged 5 to 30 years.
• The eruption pattern method offers the highest precision for younger horses aged 3 to 5 years.
• This evidence-based guidance can enhance the accuracy of age determination practices and promote better management and welfare of local horses in Nigeria.