Analysis of the principal components within the morphometric parameters of stallion spermatozoa

M Hidalgo, I Rodríguez and J Dorado

Animal Reproduction Unit, University of Córdoba, Spain

Computer-assisted sperm morphometry systems usually analyse a large number of objective variables, which can be used for classification techniques using  statistical modelling procedures. The aim of this study was to reduce the morphometric parameters of stallion spermatozoa to principal components, which  explain as much as possible of the information included in the original variables. Eajaculates were collected by artificial vagina from 8 adult stallions of the  Arabian, Thoroughbred, Anglo-Arabian and Spanish-Thorougbred breeds. Morphometric slides were stained with Harris’ haematoxylin and at least 200  spermatozoa were analysed using the Sperm Class Analyser (Microptic, Spain). The Principal components (PC) matrix was calculated statistically over the  morphometry data obtained. Morphometric parameters were classified in 4 PC. The PC1 was correlated with the sperm head size parameters

[length(0.87),  width(0.79) area(0.96) perimeter(0.94)], PC2 with the head shape [ellipticity(0.99), rugosity()0.96), elongation(0.99)], PC3 with the midpiece size [width (0.93)  rea(0.92)] and PC4 with the midpiece insertion parameters [distance(0.98), angle(0.99)]. The reduction of the data to PC permitted grouping sets of  highly correlated variables, which could explain 90.5% of the total variance. It is concluded that morphometric parameters of stallion spermatozoa were reduced  to four PC for head size and shape, and midpiece size and insertion respectively, which retained a higher percentage of the information obtained with the original variables (Supported by PTR1995-0826-OP).

Reprod Dom Anim 41, 311–377 (2006)