Equine Health Update EHU 2020 Issue 02 | Page 27

URT endoscopy | EQUINE (Microsoft Excel 2007, Microsoft Corp, Redmond, WA, USA). Results were expressed as a prevalence for each grade. For analysis of the effects for gender on RLN grading, horses with grades 1 and 2 were considered “normal” and horses with grades 3 and 4 “abnormal”. A Fisher’s exact test (Fisher 1922:87-94) was used to determine if there was a relationship between gender and grade, due to one or more instances of the expected value being less than 5. For comparison of the effects of age on grade, and sales year on grade, a Kruskal-Wallis test was performed (Gibbons 1976). For all comparisons, a value of P < 0.05 was considered significant. Statistical Analysis was performed by SMM using SPSS (IBM Corp. Released 2017. IBM SPSS Statistics for Windows, Version 25.0. Armonk, NY: IBM Corp.). Results 858 horses out of a total of 4149 offered for sale over the seven-year period (20.68 %) were examined. The horses endoscopically examined per sale ranged between 13.71 – 26.85 %. There were 494 colts (57.58%) and 364 fillies (42.42%) examined, with a mean age at time of examination of 18.1 months (range 13-26 months) from 2013 to 2019. The mean percentage ± standard deviation for grade 1 was: 84.04% ± 9.98, grade 2: 14.49% ± 10.69, grade 3: 0.71% ± 0.57 and grade 4 was: 0.76% ± 0.94% (Table 3). Analysis of the effects for gender on RLN grading showed no significant difference between colts and fillies with grades 1 and 2 or with grades 3 and 4 RLN (Table 3). There was also no significant effect of age on grade. There was no significant difference in grades compared by sales year. Discussion Table 4. Gender versus RLN grade in the present study Gender Grade 1 Grade 2 Grade 3 Grade 4 Colts 407 80 3 4 Fillies 305 56 2 1 Total 712 136 5 5 Table 3: Endoscopic examination grading of recurrent laryngeal neuropathy of yearlings at South African sales from 2013 to 2019 Grade 2013 2014 2015 2016 2017 2018 2019 % Mean ± STD n % n % n % n % n % n % n % Grade 1 65 95.96 81 78.64 67 83.75 119 85.61 133 92.36 142 87.12 105 65.22 84.04 ± 9.98 Grade 2 1 1.47 21 20.39 10 12.5 19 13.67 10 6.94 19 11.66 56 34.78 14.49 ± 10.69 Grade 3 1 1.47 1 0.9 1 1.25 0 0 1 0.69 1 0.61 0 0 0.71 ± 0.57 Grade 4 1 1.47 0 0 2 2.5 1 0.72 0 0 1 0.61 0 0 0.76 ± 0.94 Total horses 68 103 80 139 144 163 161 n: Number of individuals, %: percentage, STD: Standard deviation • Volume 22 Issue 02 | June 2020 • 27