Jaremchuk O. Hygienic estimation of housing methods of dry-off cows in reconstructed barns

Experimental data on advantages of the use of free-stall system with combined boxes in separate sections for housing of dry-off cows and reconstruction of existing cattle barns has been shown in the thesis. As compared to the tie-stall system of housing of dry-off cows together with milking cows, free-stall housing allows for the less fluctuations of temperature, lower relative humidity and concentration of ammonia, carbon dioxide and amount of microorganisms in the air as well as significantly lower noise level. Microclimate of reconstructed barns corresponds to technical requirements for barn construction. It is has been proved, that dry-off cows, which have been kept together with milking cows during the dry-off period had greater variation of non-specific reactivity and lower milk performance as compared to the cows kept in free stalls or tie stalls in separate sections of the barn. Cost of milk production was by 9-12% lower and return on investment was by 10-12% higher at housing of dry cows in separate sections of the barn as compared to the same indexes when dry-off cows were kept together with milking cows. For the purpose of barn reconstruction and estimation of group size, it has been proposed to use the duration of stay of an animal in a certain age group. It has been proved that the most effective method of housing of dry-off cows is free-stall housing in isolated sections of the barn equipped with combined boxes of 1500 mm in width and 1200 mm in length, providing rest area on a wooden floor (1500 - 2000 mm).