I. Ahmad, K. Javed¹ and A. Sattar

Research Institute for Physiology of Animal Reproduction, Bhunikey (Pattoki) District Kasur, ¹Department of Livestock Production, University of Veterinary and Animal Sciences, Lahore, Pakistan.

    A study of chromosomal analysis for 200 breeding bulls of different breeds of cattle (Jersey, Holstein Friesian, Sahiwal and Cross-bred) and Nili-Ravi buffalo, maintained at Semen Production Unit, Qadirabad and Livestock Experiment Station, Bhunikey (Pattoki) was carried out. Micromethod was adopted for leukocyte culture and chromosomes were trapped at metaphase stage. The diploid number of chromosomes in all breeds of cattle was found to be 60 (58 autosomes and 2 sex chromosomes: XY), while this number in Nili-Ravi buffalo bulls was 50 (48 autosomes and 2 sex chromosomes: XY). All the autosomes and sex chromosomes in males of both species were found normal.

Key words: Karyotyping, micromethod, cattle, buffalo, bulls.