Prevalence of chromosome anomalies in a deer farm with fertility decline in Malaysia

Abstract

Background: A number of factors are known to reduce fertility rate in animals and one of the important categories of such factors is chromosome anomalies. They can occur with or without causing phenotypic abnormalities on animals; in some cases, they may directly affect meiosis, gametogenesis and the viability of conceptus. In many instances, balanced structural rearrangements can be transmitted to offspring, affecting fertility in subsequent generations. Aim: This work investigated the occurrence of chromosome aberrations in Rusa timorensis, Rusa unicolor and Axis axis raised in a nucleus deer farm in Malaysia with a history of declining fertility of unknown origin. Materials & methods: Blood samples were collected from 60 animals through venipuncture, cultured for 72 h and arrested at metaphase. SmartType® and Ideokar® software were used to karyotype the chromosomes. Results: We found 15 out of the 60 animals screened from both sexes harbor some form of chromosome aberration. Chromosomal aberrations exist at the rate of 25% and may not be unconnected with the observed reduced fertility on the farm. Further investigations should be carried out, especially on the offspring of the studied animals to transmission of these aberrations. The animals that are confirmed to transmit the chromosomal aberrations should be culled to arrest the propagation of their abnormalities.