Figure 1.

Timeline of treatments and slaughter. The cows of NEG and POS cohorts were divided into three groups (G1, G2, and G3) for treatment and for slaughter, so that the collection of brains was within a 1-hour period. The assignment to groups balanced POS and NEG cows as much as was possible. Initially, the estrous cycles of all cows were synchronized with two injections of Cloprostenol as indicated in Materials and methods. Between Days 1 and 7, the estrus detection was carried out as indicated in Supplementary 1 and on Day 7, ultrasound was performed on all cows. Thereafter, the treatment of G1, G2, and G3 was staggered by 1 day. Buserelin was administered and the cows received CIDRs for 6 days. Commencing on Day 13 and staggered by one day for each group, the CIDRs were withdrawn and the cows were given Cloprostenol to ensure the demise of any corpora lutea. One day later, the cows were blood sampled, transported to a local abattoir, and killed between 1500 and 1600 h.