Cost of abortion at 240 days after service

These cows abort about 40 days before the expected calving date. They are dry at the time of abortion and start a second lactation.

Calculating costs

There is a smaller effect in cow performance than in cows that abort at an earlier stage.

One positive effect is that the the calving interval of the cows is reduced by 40 days. It is however assumed that the yield from the second lactation is reduced by 8%.There is also a higher mortality rate of calves born (36%) and surviving calves are smaller.

UK example - Cow aborting at 240 days after service

Cost of lost milk yield

The higher mortality rate and smaller size of surviving calves results in a reduction of £31 per abortion.

Calving to conception interval

Typically cows in the UK have a voluntary waiting period of 65 days, a conception rate of 42% and a heat detection rate of 50%. Thus, in such circumstances, the calving to conception is 130 days and calving interval 410 days.

If an abortion occurs at 240 days of gestation:

1. The “voluntary waiting period” is 20 days as with a normal calving.
2. Heat detection is not affected at this stage of abortion and is usually 50%.
3. Conception rate is usually 42%.

Calving to conception is usually 130 days, with the 40 days off calving to conception is now 90 days.

Records show that the normal 7 oestrus periods are offered to these aborting cows to get pregnant. 19% of aborting cows are thus culled if they do not get pregnant.

Cost per abortion

When the benefit of the shorter calving interval is added to the cost of calf loss and milk yield reduction, the cost of an abortion at 240 days of gestation is £400 (lower yielding) to £500 (higher yielding).

Taken from information provided by Dr. R. J. Esslemont.