Title:
Comparison of five different methods to assess the concentration of boar semen
Author(s):
D. MAES, T. RIJSSELAERE, P. VYT, A. SOKOLOWSKA, W. DELEY, A. VAN SOOM
Abstract:
Both for research and practical purposes, accurate and repeatable methods are required to assess theconcentration of boar semen samples. Since the method which is used may influence the results considerably,the aim of the present study was to compare 5 frequently used techniques to determine boar semenconcentration. Fifty ejaculates were collected from 37 different boars at an artificial insemination centre.Subsequently, each ejaculate was analyzed for sperm concentration by means of 2 different types ofcolorimeters (Colorimeter 1: Model 252, Sherwood Scientific Ltd, Cambridge, UK ; Colorimeter 2: Ciba-Corning, Schippers, Bladel, The Netherlands), the Bürker counting chamber (golden standard), and theHamilton Thorne Analyzer (Ceros 12.1) using 2 types of Leja chambers (the ‘former’ and the ‘recentlydeveloped’). Each ejaculate was assessed 5 times with each of the 5 methods, and the repeatability, expressedby coefficient of variation (CV), was determined for each method. The different methods were compared usingPearson’s correlations and limits of agreement. The colorimeters yielded the lowest CV’s (both 3.7%), whilethe former Leja chamber resulted in the highest CV (12.4%). Moreover, significant (P<0.01) and highcorrelations (r>0.71) were found between the results obtained by the different methods. The limits ofagreement plots showed that none of the methods consistently over- or underestimated the spermconcentrations when compared to the Bürker chamber, although there was a tendency toward higher overorunderestimation in highly concentrated sperm samples. Based on our results, there were no majordifferences in the assessment of sperm concentration between the evalua ted methods. The choice of methodused in a laboratory could therefore be based on factors such as cost, number of samples to be assessed andpractical use, without thereby negatively affecting the validity of the results thus obtained.