Dear Ravjibhai,

Conception Rate: is the number of pregnant cows over total of services in a given period of time.

CR (%) = (No. of Pregnant Cows x 100) / Total Services

Pregnancy Rate: is the result of conception rate (CR) x the service charge (SR). Measures how fast cows get pregnant every 21 days, therefore it is measured in a time interval of 21 days.

PR (%) = Conception Rate (CR) x Service Rate (SR)

Before, is important to know that:

Service Rate: is the number of eligible cows served (inseminated, covered by the bull or implanted with embryo) within a period of 21 days.

SR (%) = Number of Served Cows / Number Eligible Cows

where

Eligible Cows are all cows out of the voluntary waiting period (VWR*), empty and inseminated unconfirmed minus the expected conception.

*WVR is It is the period that goes from the partitution to the time at which the cow is first eligible for insemination. Usually the wait is 35 days for the uterus returns to the normal size and the cow resumes normal estrus activities. But the WVR will varies from 40 to 60 days from farm to farm.

You can find more informations of WVR at http://www.selectsires.com/resources/reprodocs/voluntary.pdf

Other zootechnical rates:

Fertility or Birth Rate: is the way to measure the outcome of the females that were submitted to coverage, engaged and how many have led to full term gestation.

BR = Number of calves born x 100 / Number of females in coverage

Intrauterine Mortality Rate: is the% of losses of animals that were aborted, reabsorbed or stillborn.

IMR = Number of pregnant females - Number of cows giving birth x 100 / Number of pregnant females

Weaning Rate: the total number of weaned animals in relation to cows exposed for breeding within a given agricultural year.

WR = Number of weaned calves x 100 / Number of females in coverage

Best regards,

Pedro

see here; http://adph.org/healthstats/assets/Formulas.pdf

Thank you sir

pregnancy rate takes into account the success in heat detection as well, while conception rate only the success of insemination services rate

Difference between conception rate and pregnancy rate

The answer of Mr. Pedro Nacib Jorge Neto in endorsed.

Conception rate is the percentage of cows pregnant divided by the number of cows inseminated during 21 days. The pregnancy rate is calculated by multiplying the heat detection rate by the conception rate.