GRAZING BEHAVIOR OF NEW ZEALAND HOLSTEIN COWS WITH ACCESS TO SHADE

Access to shade decreases heat stress of grazing dairy cows, but may reduce their time. It was hypothesized that access would alter behavior New Zealand Holstein cows. The objective evaluate the distribution time use cows with and without in a temperate sub-humid climate summer rainfall, where mean annual temperature varies between 12 (January) 18 °C (May). During warm (May) cool (October) seasons 2017, two lots nine lactating grazed treatments, (S) (NS) access. Behavior recorded every 10 min for 5 d per period. response variables were: times; rumination standing, prostrate total; resting total. data were classified as diurnal (07:00 19:00 h) nocturnal (19:00 07:00 h); former grouped into four shifts according Temperature Humidity Index (TIH) solar radiation. analyzed general linear model MIXED procedure. In season (19 °C. precipitation 44.3 mm) 16 % less (p ≤ 0.05) higher THI radiation, being percentage use. (16 °C, 62.0 at times (71.0) radiation (880.5 Wm-2) S ruminated standing 44 longer 0.05), total 30.7 than NS; latter rested 22.5 0.05). modified Mexico.