Relationship Between Pre-fresh NEFAs, Fresh Butterfat Percentage, Progesterone Levels Following Pre-Synch and Pregnancy Rates

摘要

As herd size and milk production increase on modern dairies, it seems to be at the expense of fertility, increasing days open, declining pregnancy rates and rising cost associated with each pregnancy. To determine which service was the best time to use more expensive semen, a large commercial dairy in central Michigan investigated progesterone levels in cows following a Pre-synch protocol. Thi^^as followed by a prospective study, beginning with cjows in the dry period, with the objective of relatingpre-breeding progesterone levels to risk factors in the transition period.