Insemination strategy based on ovulation prediction in dairy cattle

Cal ving ra tes af ter first in se mi na ti on are of ten less than 50% in prac ti ce.Part of this low per cen ta ge might be ex plai ned by wrong ly ti med in se mi na ti ons.Our hy po the sis is that it is bet ter to time in se mi na ti on ac cor ding to ovu la ti on in ste ad of ac cor ding to be ha vi o ral es trus, but up to now it has not been pos si ble to pre dict the time of ovu la ti on in prac ti ce.So, to bet ter time in se mi na ti ons in prac ti ce, the re is a need for pre dic tors of ovu la ti on time.The re fo re, the re la ti ons hip be tween va ri ous es trus cha rac te ris tics and time of ovu la ti on was stu died to in ves tiga te whe ther the se cha rac te ris tics could pre dict time of ovu la ti on.First stan ding heat was dis play ed 26.4±5.2hbe fo re ovu la ti on.The in cre a se in num ber of steps du ring es trus pre dic ted the time of ovu la ti on (29.3±3.9h)best.The next ques ti on was: What is the best time for in se mi na ti on re la ti ve to ovu la ti on?When this time is known, an in se mi na ti on stra te gy can be for mu la ted.It was found that in se mi na ti ons per for med 24 to 12h be fo re ovu la ti on re sul ted in the hig hest num ber of good qua li ty em bry os at Day 7.This me ans that the op ti mal stra te gy is to in semi na te 5 to 17h af ter the first in cre a se in the num ber of steps.This stra te gy will re sult in op ti mal ti med in se mi nati ons re la ti ve to time of ovu la ti on. SA MEN VAT TING