title: Influence of breeding method on milk productivity of first-calf heifers in different climatic conditions of the Russian Federation
abstract: The study included more than 27,000 first-calf heifers of the Holstein breed, raised in four climatic zones of the Russian Federation: subtropical (Republic of Crimea), moderately continental (Voronezh, Leningrad, Moscow regions), sharply continental (Republic of Bashkortostan, Novosibirsk, Amur, Chelyabinsk regions) and Arctic (Arkhangelsk region). The milk productivity of heifers obtained by within-line selection (Group I) and line crossing (Group II) was evaluated. It was found that in the su
journal: Veterinariya Zootekhniya i Biotekhnologiya