Abstract
Sixteen periparturient Holstein cows calving during summer and autumn were fed to meet maintenance plus last 2 month of gestation level of TDN (MP) and 1.2 time of MP level (HMP). Dry matter intake of cows fed at HMP level during summer and autumn decreased by 1 and 2% of the offered feed in 1 week prepartum, respectively, and cows fed at MP level consumed all of the offered feed. Rectal temperatures at 08 : 30 h of cows fed at HMP level were higher than those of cows fed at MP level. Blood hematocrit and hemoglobin of cows increased during summer and were higher for cows fed at HMP level. Plasma total protein and glucose of cows during summer were higher than those during autumn, and the increased feed intake elevated plasma total protein and glucose. Plasma urea-N of cows fed at MP level was higher than that of cows fed at HMP level during autumn. The increased feed intake decreased plasma nonesterified fatty acid of cows during summer and autumn. These results suggest that blood components of periparturient cows are altered by calving season and feeding level.