Effect of evaporative cooling and altitude on dairy cows milk efficiency in lowlands

• Published in: International journal of biometeorology Vol. 64; no. 3; pp. 433 - 444
• Main Authors: Broucek, Jan, Ryba, Stefan, Dianova, Marta, Uhrincat, Michal, Soch, Miloslav, Sistkova, Marie, Mala, Gabriela, Novak, Pavel
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-03-2020; Springer Nature B.V
• Subjects: Air flow; Altitude; Altitude effects; Animal Physiology; Animals; Biological and Medical Physics; Biophysics; Cattle; Cooling; Cooling systems; Cow's milk; Dairy cattle; Dairy farming; Dairy farms; Dairying; Earth and Environmental Science; Environment; Environmental Health; Evaporative cooling; Farms; Female; Heat stress; Heat Stress Disorders; Heat tolerance; High temperature; High temperature effects; Housing; Humidity indexes; Lactation; Lowlands; Meteorology; Milk; Milk production; Original Paper; Plant Physiology; Sea level; Temperature effects; Ventilation; Free-stall housing; Evaporative cooling; Environment; Cow; Heat stress; Milk yield
• ISSN: 0020-7128; 1432-1254
• DOI: 10.1007/s00484-019-01828-5

The objective of this current work was to determinate the effect of high temperatures on milk production of dairy cows in southern Slovakia in the year 2015. The hypotheses that milk production is influenced by the altitude and cooling were tested. Production data included 227,500 test-day records belonging to 34 Holstein breed herds situated in lowlands, 115 to 150 m above sea level (ASL) and kept in free-stall housing. Dairy farms were classified into groups based on cooling system. The first group of cows (19 herds) was cooled evaporative (foggers) and forced ventilation, and the second group (15 herds) was using cooled only forced ventilation (automatically controlled fans in housing and feeding areas). During the period from May to September, 36 summer and 22 tropical days were recorded, 37 days had a mean thermal humidity index value above 72.0, and on 34 days we recorded mean values above 78.0. The highest milk yields were recorded at the altitude 1 (115 m ASL) (9219.0 kg year
−1
; 10327.0 kg year
−1
) and the lowest at the altitude 2 (126 m ASL) (7598.7 kg year
−1
; 8470.21 kg year
−1
) (
P
< 0.001). Dairy cows cooled evaporative milked significantly more milk than cows cooled only with forced air flow (9650.4 kg vs. 8528.0 kg;
P
< 0.001). Fat and protein production differed also significantly (364.0 kg vs. 329.5 kg,
P
< 0.001; 312.2 kg vs. 279.7 kg,
P
< 0.001). It can be concluded that not only heat stress but also location farm above sea level can affect milk production. Evaporative cooling associated with increased air velocity is the appropriate protection against high temperatures.