Effects of age, temperature-season, and breed on blood characteristics of dairy cattle.

Two hundred twenty four dairy cattle (6 mo to second calving) representing four breeds (169 Holstein, 24 Guernsey, 19 Jersey, 12 Brown Swiss) were used to determine effects of age, temperature-season, and breed on blood characteristics. A total of 1183 blood samples were collected by jugular venipuncture in the middle of each temperature-season. Covariate age affected blood profile except for hemoglobin, oxyhemoglobin, glutamic-oxalacetic transaminase, and albumin. Temperature-season increased or decreased all measures except enzyme creatine phosphokinase, total creatine phosphokinase, calcium and phosphorus. Years differed for all measures except hemoglobin and oxyhemoglobin. Except for enzyme creatine phosphokinase, total creatine phosphokinase, and phosphorus, breeds differed in other measures. There were interactions between temperature-season and year, temperature-season and breed, and year and breed. Differences among temperature-seasons were not consistent from year to year. Breed differences were not consistent from temperature-season to temperature-season for calcium or protein-bound iodine. Breed differences were not consistent from year to year for glutamic-oxaloacetic transaminase, total protein, albumin, or calcium.