Продуктивное долголетие голштинских коров ленинградской популяции при разных способах содержания

Abstract

To identify the advantages of a tethering system (TS) or loose-housing system (LHS), a comparative analysis of the level of milk productivity and the duration of productive longevity of cows in the Leningrad Region was carried out for a livestock of 4,272 cows that left in 2015–2019. The following indicators were calculated: period of productive use (PPU) – age in days from the first calving to the retirement of the cow, lifetime milk yield (LTMY); milk yield (kg) for 1 milking day, for 1 day of PPU and 1 day of life (Efficiency of Milk Production – EMP) – calculated by dividing lifetime milk yield by the number of milk days, PPU or life. With TS the LTMY is higher by 10,634 kg, which is obtained for 107 additional days of their productive use, milk production for 1 day of milking, the day of use, EMP is higher by 8,2 kg, 6,7 kg and 4,6 kg, respectively, the majority of cows have an EMP level in the ranges of 10,01–15,00 kg of milk (32,0%) and 15,01–20,00 kg (38,2%), and 11,0% of animals have reached an EMP level of more than 20,00 kg of milk. With LHS mainly cows are concentrated in the ranges of 5,01–10,00 kg of milk (43,6%) and 10,01–15,00 kg of milk (46,6%). Desirable cows with LTMY over 30 thousand kg, and in this range, the EMP is almost 10 times higher with TS (43,9 instead of 4,5%). The results obtained cannot be attributed to the advantages of TS. This is confirmed by the great influence of the father on the EMP (factor «Sire» – 0,679) or the inherent genetic potential of productivity, and only by 0,268 system (factor «System of housing») and by 0,296 (factor «Farm») housing conditions on the farm. The «System of housing» influences more on milk yield per 1 day of PPU than on EMP and LTMY (0,342 instead of 0,268 and 0,110, respectively). The effectiveness of LHS is evidenced by the fact that when comparing animals with the same level of EMP under this system, they are used for a longer time and, accordingly, produce more milk per life. So, with a level of 5,01–10,00 kg of milk, cows have a LTMY of 18,1% more with LHS, which were used for 0,54 lactation with PPU for 211 days longer than analogs with TS. A similar trend is observed at the level of 10,01–15,00 kg (+20,8%, +1,17 lact., +461 days) and at the level of 15,01–20,00 kg (+11,3%, +1,18 lact., +499 days). Therefore, for profitable dairy production with a LTMY of more than 30 thousand kg of milk during the PPU of Holstein cows with a LHS, attention should be paid to the level of the inherent genetic potential of productivity (according to the analyzed sample, at least 8000 kg of milk), that is, to select bulls with high breeding qualities.