Introduction In cattle a lethal genetic disease called Bovine Leukocyte Adhesion Deficiency (BLAD) has been reported that affect the hemopoeatic system of an animal. In the last decade, this disease gained significant economic importance. It has also been recorded in canine and human population (GERARDI, 1996). The molecular basis of this disease involves an aspartic acid to glycin substitution at amino acid 128 of the gene encoding CD18 sub-unit of beta 2 integrin. The mutation is considered lethal because homozygous animal dies before reaching sexual maturity. In 1990s, this disease was the most common and widespread genetic disorder in HF cattle worldwide (CZARNIK et al., 2007). For example, the occurrence BLAD heterozygous sires and heifers during the period 1993-1998 in Czech Holstein was 13.9% and 10.7 %, respectively (CITEK et al., 2008). India embraced artificial insemination as the method of rapid dissemination of superior genetic potential within indigenous cattle breed in the country. During the period between 1961 and 1978, it had imported around 1470 bulls and 6165 females of exotic breeds of which 275 bulls and 1825 females were of Friesian and HF breeds while most others were Jersey. More than 23 farms of HF breed together contributed to the semen freezing network majority of which were established under the Operation Flood Program in cooperation with National Dairy Development Board with assistance from Governments of Switzerland, UK and USA (MUKHOPADHYAYA AND MEHTA, 2002). This indicates that a significant inflow of exotic genetic material within the country had occurred that formed the basis of enhancement in heritable productivity enhancement capabilities within the organized diary sector in the country. BLAD was first identified in North American Holsteins which were routinely exported to different other national cattle populations in the world (KERHLI et al., 1990). The molecular basis of this disease is interesting. It occurs due to deficient CD18 proteins generated due to single nucleotide polymorphism in the corresponding gene. These proteins are component of adhesion molecules on the surface of neutrophils. Adhesion of neutrophils to the endothelial cells is an important step in immediate combating of infections. Due to this mutation, the neutrophils fail to adhere to the endothelial cells this compromising with the immediate immune response capability of an individual when challenged by a pathogen. Hence animals homozygous for this mutation suffer from recurrent infection and require continued antibiotic therapy (HEALY, 1996). It is because of this, most descendents of North American Holsteins including the well known Ivanhoe Bell, a BLAD founder bull, replaced those of LMKK in Australian artificial breeding centres (HEALY, 1996).

Several other countries including Japan (NAGAHATA et al., 1997), Germany (TAMMEN et al., 1996) and India (MUKHOPADHYAYA AND MEHTA, 2005) have taken proactive steps to eradicate this genetic disorder from their breeding population (MUKHOPADHYAYA et al., 2000). There are several methods developed for detection of the ‘A’ to ‘G’ mutation in the CD18 gene. These include non-isotopic Ligase Chain Reaction (BATT et al., 1994) and PCR-RFLP (SHUSTER et al., 1992). However, the most common method of detection of this genetic disease is the one based on PCR-RFLP because of the cost effectiveness and ease of operation.