Location of the groups in the affected herd. A. Milking pallor B. Euthanasia area. 1. First lactation cows 2. Second lactation cows. 3. Pre-calving group 4. Replacement heifers pending insemination and in early pregnancy 5. Replacement heifers (10-12 months old) 6. Pregnant replacement heifers 7. Dry cows. 8. High parity 9. Fattening calves. 10. Suckling calves.