Expression and differential expression analysis of milk samples from healthy and diseased diary cows.

Expression and differential expression analysis of milk samples from healthy and diseased diary cows. Diseases were grouped by their occurrence in the mammary gland or extra-mammary. Furthermore, the diseases were classified by their severity. All cows were examined thoroughly by the dairy herd manager, trained staff, or a veterinarian. Expression and differential expression was assessed by using the Affymetrix Bovine Genome Array (GPL2112). Control animals (2-4 years old, 1st to 3th lactation, one animal 4th and one 8th lactation) showed no clinical signs of disease and had no abnormalities in the udder or milk. Their somatic cell count (SCC) was less than 100,000 cells/ml milk. Most of the control samples were taken during early lactation (10-100 days post-partum, dpp). Diseased cows were in their 1st to 8th lactation within 10-220 dpp. We analyzed 6 biological replicates each from milk samples from healthy diary cows, diary cows with mastitis and diary cows with endometritis.