Browsing by Subject "EBV"

Patellar luxation is a typical orthopaedic disorder in small sized dogs. Patella can luxate either medially or laterally, medial luxation being by far more common than the lateral luxation. PL is considered hereditary since certain breeds have great susceptibility to get the condition, and the symptoms may occur at young age. PL is diagnosed by following the so-called Putnam’s scale where the stifle joint is palpated and manipulated. PL is graded from 0=normal…4=permanent luxation. The aim of this study was to estimate the variance components and the heritability of PL, to visualize PL’s genetic trend and to calculate the genetic correlation between left and right stifle and between PL and hip dysplasia (HD) in Japanese Spitz. The PL, HD and pedigree data were provided by the Finnish Kennel Club. Data were modified with both R-program and Microsoft Office Excel. The pedigree check was performed with RelaX2 program and variance component analyses were done with DMU program using the restricted maximum likelihood method. Heritabilities (h2) were from very low to low depending on the model and breed. When the dependent variable was the mean of left and right patellae of an individual the lowest heritability was in the Pomeranian h2=0.03 and highest in the Chihuahua h2=0.18. The genetic correlation of left and right patellae was 1 in all breeds which suggests that they are genetically the same trait. In the Japanese Spitz the genetic correlation between PL and HD was -0.05. The genetic trend of PL was favorable in the Chihuahua and the Japanese Spitz. In the Pomeranian the trend was negative and neutral in the Finnish Spitz. Based on the results, the selection against PL has not been efficient. In future, patellae health should be controlled by using breeding indexes because the heritability of PL is low. Also, improvements in phenotyping could lead to more accurate selection.