Proceedings of the World Congress on Genetics Applied to Livestock Production, 11. 403 Genetic diversity and breed proportions of Indian stud cattle E.M. Strucken 1 , D.C. Hidalgo 2 , V. Ducrocq 2 , A. Pande 3 , M. Swaminathan 3 & J.P. Gibson 1 1 University of New England, Animal Science, Armidale, 2351 NSW, Australia estrucke@une.edu.au (Corresponding Author) 2 GABI, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France 3 BAIF Development Research Foundation, Warje, Pune 411058, India Summary India is the world’s leading milk producer, however, average milk yield per animal is low. Most of India’s cattle milk is produced by indigenous breeds, followed by crossbred cows. Crossbreeding intensified in the 1960s and 70s with a large influx of Holstein Friesian and Jersey bulls, and an increased use of artificial insemination. Based on genotypes generated from the 50K v2 BovineHD BeadChip assay, we analysed the genetic diversity and breed composition of 242 breeding cattle sampled from the BAIF breed herds, including indigenous, exotic dairy, and crossbred animals. We compared these animals to indigenous and animals used in smallholder systems in East Africa. Key findings were: confirmation that Indian Zebu breeds are pure Bos indicus in contrast to African Zebu and Sanga breeds, which are admixtures of Bos indicus and African Bos taurus; as found elsewhere, many apparently pure animals contain some admixture from imported breeds; crossbred animals exhibit a wider range of breed composition than intended, reflecting the lack of pedigree when sampling bull mothers from smallholder farms; breed composition of purebred and crossbred animals can in future be tested using SNP data, and only those meeting the desired composition retained for breeding. Keywords: India, indicine, taurine, crossbred, cattle, cow Introduction India is the world’s leading milk producer with more than 199 million cattle (livestock census 2007), but the low productivity per animal (<1000kg per lactation) is the largest obstacle for India’s dairy sector (FAO). Nation-wide efforts to increase milk production connected rural dairy sheds to urban markets and increased the penetration of artificial insemination (AI), including the import of exotic taurine breeds to improve productivity through crossbreeding. India has 37 acknowledged indigenous breeds, amongst others Gir, Sahiwal, Red Sindhi, Amritmahal, Hallikar, Khillari, Hariana, or Tharparkar, and a large number of non-descript Zebu cattle. The advent of AI resulted in a large scale crossbreeding of exotic dairy breeds (mainly Jersey and Holstein Friesian) with non-descript Zebu cows. Today, India has 76.7 million adult cattle of which 22.3 million are dairy crossbreds. Indigenous and non-descript dairy cows contribute 26%, crossbred cows 21%, and pure exotic cows 1% of the total milk production in India (Annual Report 2016-17, Ministry of Agriculture & Farmers Welfare, Government of India). The remaining milk is produced by buffalo and goats. Crossbreeding pedigree records are sparse and hence breed proportions of the crossbred stud population in India are unreliably estimated or unknown. This study analysed 242 cattle