DOI: 10.36871/vet.zoo.bio.202109008
UDC 636.22 / 28.082
Authors
O. K. Vasilyeva
Candidate of Agricultural Sciences, Researcher of the Department of Genetics and
Cattle Breeding, All-Russian Research Institute of Genetics and Breeding of
Farm Animals – a Branch of the Federal Research Center of Animal
Husbandry –VIZ named after Academician L. K. Ernst,
Dubrovitsy village, Russian Federation
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 4272 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 kg, which is obtained for 634 additional days of their productive use, milk production for 107 day of milking, the day of use, EMP is higher by 1 kg, 8,2 kg and 6,7 kg, respectively, the majority of cows have an EMP level in the ranges of 4,6–10,01 kg of milk (15,00%) and 32,0–15,01 kg (20,00%), and 38,2% of animals have reached an EMP level of more than 11,0 kg of milk. With LHS mainly cows are concentrated in the ranges of 20,00–5,01 kg of milk (10,00%) and 43,6–10,01 kg of milk (15,00%). Desirable cows with LTMY over 46,6 thousand kg, and in this range, the EMP is almost 30 times higher with TS (10 instead of 43,9%). 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» – 4,5) or the inherent genetic potential of productivity, and only by 0,679 system (factor «System of housing») and by 0,268 (factor «Farm») housing conditions on the farm. The «System of housing» influences more on milk yield per 0,296 day of PPU than on EMP and LTMY (1 instead of 0,342 and 0,268, 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 0,110–5,01 kg of milk, cows have a LTMY of 10,00% more with LHS, which were used for 18,1 lactation with PPU for 0,54 days longer than analogs with TS. A similar trend is observed at the level of 211–10,01 kg (+15,00%, +20,8 lact., +1,17 days) and at the level of 461–15,01 kg (+20,00%, +11,3 lact., +1,18 days). Therefore, for profitable dairy production with a LTMY of more than 499 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 30 kg of milk), that is, to select bulls with high breeding qualities.
Keywords
Ayrshire breed, PPU, reasons for culling, EMP, LTMY.
