Technical note: Effects of adding shade and fans to a feedbunk sprinkler system for preparturient cows on health and performance.

The purpose of this study was to examine the effects of adding shades and fans to a feedbunk-mounted sprinkler system on preparturient Holstein cows during summer heat stress. Outcome variables included postpartum milk production, changes in body condition score, changes in serum concentrations of nonesterified fatty acids (NEFA), and incidence of postparturient disorders. Four hundred and seventy-five prepartum multiparous cows, 250 to 257 d pregnant, were randomly allocated to 2 study pens. Treatments consisted of sprinklers over the feed bunk (n = 236); and sprinklers, fans, and shades over the feed bunk (n = 239). Data were used from cows spending a minimum of 14 d in their assigned pen. After parturition, all cows were housed and managed under identical conditions. Data recorders in each pen recorded environmental temperature and humidity every 30 min. Body condition scores were taken at study enrollment, parturition, and 60 d in lactation. Following parturition, the presence of retained placenta, metritis, milk fever, and displaced abomasum were recorded for the length of the study. Milk production was measured using twice-monthly Dairy Herd Improvement Association tests for the first 60 d in lactation. Blood was sampled twice weekly in 98 cows and analyzed for serum NEFA during the last 3 wk before parturition. Cows spent approximately 28 d in their respective treatments. Average daily environmental temperature (+/- SD) in the sprinkler only treatment was 26.4 +/- 7.2 vs. 25.1 +/- 8.6 degrees C in the shade, fans, and sprinkler treatment during the length of the trial. There was no difference in body condition score changes, incidence of postparturient disorders, or serum NEFA concentrations. There was a significant difference in total 60-d milk production, and an economic benefit over the preexisting cooling system.