Evaluation of Regional Adiposity in the Neck Area of Andalusian Horses

Abstract

Reasons for performing studyAdipose tissue deposited along the crest of the neck has been associated with altered metabolic states and with an increased risk of laminitis in equids. Thickness of the neck is a phenotipic characteristic in Andalusians; however, there are no studies evaluating this condition in this breed.ObjectivesTo evaluate morphometric and ultrasonographic measurements in the neck area for assessment of neck adiposity and its associations with adiposity scores and biochemical variables.Study designA sample of 115 Andalusian horses (46 barren mares and 69 stallions, 2–15 years old) was evaluated in a cross‐sectional study.MethodsCresty neck score (CNS) was determined. Two groups were created: cresty neck (CNS ≥ 3) and noncresty neck (CNS<3) horses. Neck circumference (NC) (cm) and ultrasonography (US) of subcutaneous fat (mm) at 25% (NC0.25–US0.25), 50% (NC0.50–US0.50) and 75% (NC0.75–US0.75) of neck length were measured. Middle neck circumference (NC), neck length and height at the withers were taken to calculate neck ratios (NC0.50:height, NC0.50:neck length). Plasma was analysed for insulin and leptin. Hyperinsulinemia was defined as insulin ≥20 μiu/ml. Correlations using Pearson and Spearman coefficients were evaluated. Mean comparisons were carried out with Student's t or Mann‐Whitney tests.ResultsCresty neck condition was present in 73.9% (n = 85) of the horses and 2.6% (n = 3) were hyperinsulinaemic. Cresty neck horses had significantly higher plasma leptin, morphometric and ultrasonographic measurements. NC0.50:height was the most correlated parameter with CNS. Insulin was correlated with leptin levels and all morphometric measurements. Insulin and leptin were correlated only with US0.75.ConclusionsAndalusian horses’ neck score, despite their thick necks in the majority of individuals, does not have a good correlation with plasma insulin and leptin levels. Since in Andalusian horses, neck scores may be overestimating obesity, further studies on ultrasonographic fat measurements are needed.Ethical animal research: The university committee for the ethical use of animals approved all procedures. Owners gave informed consent for their horses’ inclusion in the study. Sources of funding: None. Competing interests: None.