(Wydawnictwo Uczelniane Zachodniopomorskiego Uniwersytetu Technologicznego w Szczecinie, 2019) Wójcik, Piotr; Meller, Mariusz; Mróz, Piotr; Department of Cattle Breeding, National Research Institute of Animal Production, Kraków, Poland; The Dobrzyniewo Stud Ltd., Poland; Department of Cattle Breeding, National Research Institute of Animal Production, Kraków, Poland
The study was performed with Polish Holstein-Friesian (PHF) cows maintained in
changing environmental conditions. Two groups of animals were established (with and without
an outside yard), which were subjected to temporary crowding. The effects of age and rate of
change in stocking density on milk output and milking duration were also determined. It was
found in the study that cow age is a variable highly differentiating the cows in milk yield and milk
quality parameters. The change in housing conditions (crowding) reduced milk yield by 8.92 kg
in the section without outdoor access and by 7.46 kg in the section with outdoor access. In both
experimental groups, milking time decreased with decreasing milk production. Outdoor access
alleviated the adverse effects of increased stocking density and reduced stress.