MILK PRODUCTIVITY OF COWS OF THE UKRAINIAN RED-AND-WHITE DAIRY BREED DEPENDS ON THE ORIGIN AND COMPATIBILITY OF THE BULLS
Authors: Krugliak T. O. , Krugliak A. P. 
Published: January 2024

We studied the effectiveness of the bulls selection to the cows of the Ukrainian Red-and-White dairy breed (n = 490 mother-daughter pairs) different bloodlines and related groups. The level of milk productivity of first-borns cows (n = 490 mother-daughter pairs) for 305 days of the first lactation, obtained as a result of the compatibility of the bulls. The parents of the first-borns cows were four breeding bulls (bloodline Regal 352882, RG Valiant 1650414 and R. Sovereign 198998) of the Ukrainian Red-and-White dairy breed and one bull (Jornado Red 114386106, RG Chief 1427381) of the Holstein breed, and their mothers – from 11 bulls of three origin bloodlines (Dynemik 359742, Leader 1926780 and Hanover 1629391) and 4 related groups. A total of 29 combinations of interbloodline selection were investigated. The highest level of milk productivity was characterized by the daughters of bull Viter 4444 of the bloodline Regal 352882 (7191.5 ± 75.90), Jornado Red 114386106 of the Holstein breed of foreign selection, which belonged to the related group Chief 1427381 (the milk yield for 305 days of the first lactation was 7188.7 ± 31.05 kg), and Artek 344 related group Valiant 1650414 (the yield for 305 days of the first lactation was 7052.5 ± 75.51 kg). A statistically significant difference was established between milk yield indicators for 305 days of the first lactation between the groups of cows of the bull Jornado Red (related group Chief 14273381) and Luchnov 471 (r. g. R. Sovereign 198998) – +380 kg (td = 4.22 p < 0.001) in favor Jornado Red. Between cows of the bull Viter 4444 (bloodline Regal 352882) and Luchnov 471 (R. Sovereign 198998) – +383 kg (td = 3.38 p < 0.001) in favor of Viter 4444. Animals of the bulls Kanzler and Viter 4444 have the highest fat content in milk (3.71%), and cows of the related groups Valiant 1650414 characterized by the lowest fat content in milk (3.68%). A statistically significant difference was established between the amount of total milk fat and protein in the milk of cows of different bulls.
A total 20 successful combinations of bulls were found, the first-borns cows of which were characterized by an increased milk yield on average across all successful compatibility by +96 kg (1.5%), milk fat yield – by +6,1 kg (2.3%) and total protein – by +5.3 kg (2.3%) from the average level of phenotypic manifestation of milk productivity traits of the daughters of all 5 evaluated bulls. The increasing of daughters milk yield of some successful combinations was from +42 kg (0.6%, sire Jornado 114386106 RG Chief 1427381) up to +296 kg (4.1%, sire Viter 4444,), milk fat from +2 kg (0.7%, sire Artek 344, RG Valiant) up to +8 kg (3%, sire Viter 4444) and protein from +1 kg (0.4%, sire Artek 344) up to +12 kg (5%, sire Viter 4444). The data, which we received, confirm the influence of the origin of cows by father on the level of their milk productivity and the high combining ability of individual improver bulls with the mothers of other genealogical formations.