Throughout the study cows were milked three
times per day (06:00, 14:00, and 21:00 h) in milking parlors. All cows were administered rbST
(Lactotropin, 500 mg of zinc bovine somatotropin,
Elanco Animal Health, Mexico) via subcutaneous
injection every 14 d beginning at 60 days in milk
(DIM) and continuing until 2 weeks before drying
off. Lactation order in the study varied from 1
to 8, with cow body condition scores ranging
from 2.75 to 3.5 (scale 1 to 5). The average milk
yield for 305 days was approximately 13,200 kg
throughout the duration of the study. The average
number of inseminations was 3.7 (range = 1 to 14
inseminations). The average DIM was 234 (standard
deviation = 89).