Alleviation of heat stress with Tasco in dairy cows

The present study determined the impact of Tasco-14, Ascophyllum nodosum, on heat stress in dairy cows. Thirty-two Holstein cows were blocked by parity and DIM and assigned to treatments using a randomized complete block design, with 8 cows per treatment. The study was divided into 3 periods. In Period 1 (7 days), cows adapted to the Calan Gate system. In Period 2 (28 days) the following treatments began: Control-1 (C1); Control-2 (C-.5T); 0.25% Tasco (0.25T); 0.50% Tasco (0.5T). In Period 3 (28 days), C-.5T was changed to 0.50% Tasco in order to evaluate duration of feeding Tasco. Cows were fed a TMR diet, consisting of corn silage/alfalfa haylage and corn. Feed intake and milk production were recorded daily. Core body temperature (Tcore) was recorded every 20 minutes with telemetric temperature transmitters (SmartStock, Pawnee, OK) placed in the reticulum. Respiration rate (RR), measured by enumeration of abdominal movements for 30 seconds, and rump (Trump) and ear (Tear) skin temperatures, measured with an infrared heat gun (Raytec, Everett, WA), were collected daily at 0700, 1600, and 1900 h. Ambient temperature (Ta) and relative humidity were recorded (Hobo, Onset Computer