Biotechnology in Animal Husbandry 25 (5-6), p 953-959, 2009 ISSN 1450-9156 Publisher: Institute for Animal Husbandry, Belgrade-Zemun UDC 636.034/3 THE STUDY OF THE MILK YIELD AND THE MAIN REPRODUCTION INDEXES OF THE INDIGENOUS SHEEP’ POPULATIONS FROM THE PRIVATE EXPLOITATIONS IN THE NORTH EAST PART OF ROMANIA I. Gilca, C. Pascal, V. Macovei, B. Pasarin, M. Dolis, S. Creanga University of Agricultural Sciences and Veterinary Medicine, Faculty of Animal Sciences, Iasi, Romania Corresponding author: igilca@uaiasi.ro Original scientific paper Abstract: In this research paper we proposed to compare, at the first and second lactations, respectively at the first and second parturition, the milk production and the main reproduction indexes, in both indigenous sheep breeds from the North East part of Romania (Tzigai and Merinos of Palas). The sheep of Tzigai breed were analyzed with contemporary’s sheep from Merinos of Palas breed calved in the same period. Both breeds were kept in the same conditions and with the same feeding. The first and second lactations records were analyzed according to the following linear models: Y ij =μ + H i + S j + e ij respectively Y ijk =μ + H i + S j + J k + e ijk , The average milk production registered 108.62 kg (first lactation) and 111.20 kg (second lactation) at the Tzigai breed and 80.15 kg, respectively 82.15 kg at the Merinos of Palas breed. The difference in milk production between Tzigai and Merinos of Palas breeds, at first and second lactations, were statistically highly significant (P<0.01). The reproduction indexes pursuer was the following: fecundity, fertility, birth rate, number of lambs to wean and the potential reproductive capacity. All value of the reproduction indexes were normal and not registered the statistically difference, exception the birth rate and the potential reproductive capacity. This value was 110.25% respectively 122.31% at the Tsigai breed and 124.63% respectively 138.35% at the Merinos of Palas breed. This difference was statistically highly significant (P<0.01). Key words: Romanian sheep, milk performance, reproduction indexes Introduction The specialty literature from Romania present some data about the production and breeding capacity for all Romanian sheep, but not for different