Cytogenetic Analysis of Dairy Animals in India: An update

Animal clinical Cytogenetics started during 1960s. The majority of laboratories in India and abroad developed and started cytogenetic screening of cattle and buffaloes during last 5 decades which was parallel to human Cytogenetics. These laboratories were created almost exclusively within academic research institutions with a focus on basic research worldwide. However, a Cytogenetic screening programme in India was launched by the apex body, the National Dairy Development Board responsible for dairy development and animal improvement programmes during 1990s. Reduced fertility and infertility are major concern in dairy animals in India which could be due to poor breeding, feeding and management. However, it could also be due to chromosomal aberrations. Chromosomal aberrations might be transmitted or spontaneous generated during mitotic or meiotic cell divisions. Therefore, complete eradication of chromosomal aberrations from the dairy animal population may not be possible. In view of this the regular chromosomal screening especially of breeding bulls at the early age ought to be done This practice will not only reduce the occurrence of chromosomal abnormalities in dairy animal population rather it will save the time and amount spent on rearing of abnormal animals. Various kind of structural and numerical chromosomal abnormalities have been reported in India which is very less as compared to reported elsewhere. The chromosomal aberrations are reported mainly by conventional methods (banding of chromosomes) by which it is difficult to detect microdeletion, microduplication, microshiting translocation of minute fragments of chromosomes. The new molecular technologies like probe based fluorescence in situ hybridization (FISH) and microarray may be applied to detect minor abnormalities so that they can be correlated with infertility problems.