Histological comparison of the lamellar tissue of Iberian origin breed horses created in semi-feral conditions or in an intensive system.

Although the external conformation of wild horse hooves has been proposed as an ideal model for domesticated modern horses, histological signs of laminitis have been reported among them. With the hypothesis that the lamellar tissue of horses of Iberian origin raised in semi-feral is healthier than those raised in an intensive management system (stall confinement and high-calorie diet intake), the objective was to compare their lamellar tissues. Lamellar tissue samples were taken from the forelimb hoof of eight domesticated Mangalarga Marchador (MM) horses and from six semi-feral Marajoara (MJ) and Puruca (MP) horses. Primary epidermal lamella (PEL) and secondary epidermal lamella (SEL) were measured (length and width) in several regions, and their shapes were morphologically classified into different types. Breed groups were compared using analysis of variance, followed by Tukey or Dunn tests (P<0.05). Early signs of laminitis such as abnormal keratinization of the abaxial primary dermal lamella, tapered tips of the axial PELs, pointed tips of the SEL, nuclei condensation, and abnormal spatial orientation of the secondary epidermal basal cells (SELBC), were seen only in MM horses. MP horses had a greater interface of epidermis/dermis contact than MJ horses and more rounded nuclei in the round SELBC than MM horses. In agreement with the study hypothesis, semi-feral MJ and MP horses' lamellae were classified as healthier than MM horses, which showed early signs of endocrinopathic laminitis.

Comparison Between the Direct Method and Friedewald's Formula for the Determination of Low-Density Lipoprotein Cholesterol Serum Levels in Horses.

This study aimed to compare the use of enzymatic colorimetry and Friedewald's formula for the determination of LDL in horses. A total of 260 samples were used. Direct analysis was performed to determine low-density lipoprotein (LDL), high-density lipoprotein (HDL) cholesterol, triglycerides (TG), and total cholesterol (TC). The LDL level was calculated using the Friedewald equation (LDL= TC-HDL-TG/5). The correlations between the direct LDL analysis and the LDL calculated using the Friedewald formula were determined by Pearson's tests, and the coefficient of determination was also obtained by linear regression using SAS software (P<.05) and the kappa value. The mean value (± standard deviation) of the LDL was 22.12 (±10.34) mg/dL, and that of the result obtained by the Friedewald formula was 19.94 (±19.13) mg/dL. The correlation between the two variants analyzed in this experiment was significant, with a value of P < .001, and values of r = 0.688 and R2 = 0.4893. These results are relevant, given that recent studies have demonstrated a correlation between LDL plasma values and equine metabolic syndrome. Previous studies have reported discrepancies between the data obtained using Friedewald's method and the LDL-c values directly determined in humans and animals. The results of the present study suggest that the Friedewald method can be used to estimate the LDL plasma concentration in horses. Nevertheless, the coefficient of determination was not found to be adequate to recommend the Friedewald formula as a replacement for the enzymatic colorimetric method in determining LDL in horses.