Influence of Using Fan and Sprinkler Cooling Systems on Physiological Responses of Heat-Stressed Holstein Cows

Authors

  • S. F. Rezazadeh Baei Department of Animal Science, Azad University of Ghaemshahr, Ghaemshar, Iran; Martin-Luther University Halle-Wittenberg, 06108 Germany

DOI:

https://doi.org/10.21423/aabppro20064662

Keywords:

thermal stress, relative humidity, ambient temperature, environmental heat load, cooling systems, fans, sprinklers, lactating cattle

Abstract

Lactating dairy cattle produce large amounts of heat due to digestion and metabolic processes; this heat must be exchanged with the environment to maintain normal body temperature.

The Temperature Humidity Index (THI) could be used to evaluate thermal stress caused by the environment. This index combines relative humidity (RH) and ambient temperature (Ta) into a single value to estimate the potential environmental heat load. An environment is generally considered stressful for cattle when the THI exceeds 72. Sprinkling and supplemental airflow -to-reduce heat stress (HS) has been evaluated in many studies.

Thirty Holstein dairy cows were used in this study to evaluate the effect of three different cooling systems on physiological responses, including rectal temperature (RT), respiration (RR) and heart rate (HR), during August and September, with daily average Ta between 73 and 86°F (23 and 30°C) and Rh between 67 and 91 % at Sari City, Northern Iran.

Control cows had access to six fans (C). A second group was cooled with twelve fans (F), and the third group of cows was cooled with twelve fans and sprinklers (F/S). The maximum THI during the trial ranged from 73.1 to 99.7 (83.63 ± 3.333).

Ta, and as a result THI, were less (P<0.05) in F/S (77.8 ± 6.58°F and 74.9 ± 5.62) and F (82.4 ± 7.44°F and 78.8 ± 6.44) groups compared to the C group (83. 7 ± 7. 71 °F and 79.9 ± 6.64).

The average of RT (103.1 ± l.02°F; 39.5 ± 0.566°C), RR (79.2 ± 10.2 breaths/min) and HR (79.4 ± 4.32 beats/ min) of cows in the C group were higher (P < 0.05) than those in the F (102.6 ± 0.96°F [39.2 ± 0.638°C], 67.7 ± 12.8 and 77.3 ± 3.98) and S/F (101.7 ± 0.94°F [38.7 ± 0.521°C], 55.1 ± 12.7 and 76.7 ± 4.60) groups, respectively.

These results indicate that a cooling system based on spray and fans is an effective alternative to alleviate the negative effects of HS on physiological responses in lactating Holstein cows under warm and humid conditions.

Author Biography

S. F. Rezazadeh Baei, Department of Animal Science, Azad University of Ghaemshahr, Ghaemshar, Iran; Martin-Luther University Halle-Wittenberg, 06108 Germany

PhD Student of Martin-Luther University Halle-Wittenberg, 06108 Germany

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Published

2006-09-21

Issue

Section

General Sessions