The advancements in cattle genetics and genomics have widened the scope of understanding number of hereditary diseases in cattle, leading to the development of early diagnostic techniques to detect presence of lethal or mutant allele for a specific phenotype. Bovine Leukocyte Adhesion Deficiency decreases host resistance and increases susceptibility to fatal illnesses. Citrullinemia is a disorder of urea cycle and this condition leads to increase levels of ammonia accumulation in blood and tissues, and subsequent death. Deficiency of uridine monophosphate synthase (DUMPS) causes prenatal embryonic mortality before d 40 of gestation. Factor XI results in a bleeding disorder and the affected animals (homozygotes) have hemophilia-like disorder. Although the frequency of these alleles in the population is usually very low, it can be easily increased if heterozygous (carrier) sires are used for large scale breeding through artificial insemination program resulting in increase in the proportion of lethal alleles. As per minimum standard protocol laid down by Government of India, it is mandatory to screen each stud bull before its entry to semen collection to rule out genetically transmitted diseases. All the stud bulls were screened by single nucleotide polymorphism (SNP) genotyping for BLAD, citrullinemia, DUMPS by Custom Designed Assays from Life Technologies (a brand of Thermo Fisher Scientific) and temperature melting curve for Factor XI. BAIF Development Research Foundation has a regular genetic disorder-screening program for its own stud bull farm. To date, 400 stud bulls have been screened and not a single male carrier for such genetic disorders has been found (Table 1). Table 1. Screening for disorders in Indian stud bulls

Sr. No.	Breed	Tests carried out	No. of stud bulls screened
1	Indigenous cattle and buffaloes	Factor XI, BLAD, citrullinemia	150
2	HF and HF crossbreeds	Factor XI, BLAD, citrullinemia, DUMPS	150
3	Jersey and Jersey crossbreeds	Factor XI, BLAD, citrullinemia	100