Cost of abortion at 90 days after service

Cattle that abort at about 90 - 140 days post conception continue milking. These animals need to get pregnant again. The delay in conception means longer calving intervals and thus longer dry periods. Many cows fail to conceive again and are culled.

Calculating costs

The cost of each extra day before the cow is in calf again depends on the yield of the cow. Typically the loss can be calculated as 2% of the 305 day milk yield for each days delay. The value is linked to the price of milk.

The number of wasted days between the abortion and the second attempt to get the cow pregnant again depends on:

1. How long it is before the farmer realises that the cow is no longer pregnant.
2. How effective heat detection is.
3. The conception rate to later services.

The total number of days are calculated to give the total cost of the delay from calving to second conception. e.g.
(interval to first conception) + (number of days to the abortion (90 days)) + (number of days from abortion to second conception) = Total number of days delay.

UK example - Cow aborting between 90 and 140 days

Cost of lost milk yield

Loss of milk yield = 2% of 305 days milk yield = +£2.00/day.

The later in gestation that the abortion takes place the higher the losses - can be up to 70% higher = +£3.00/day.

Number of days lost

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

If an abortion occurs at 90 days of gestation:

1. The “voluntary waiting period” is typically 20 days.
2. Heat detection is often 20% lower than before the first conception as cows are often not under strict observation signs of heat.
3. Conception rate is usually 10% lower after an abortion.

The second conception can thus occur 282 days into the lactation period. Thus with a 280 day gestation, the final calving interval is 562 days.

Records show that aborting animals that fail to get pregnant after the subsequent oestrus are usually culled. This means that 87% of aborting cattle are culled after they fail to get pregnant.

Cost per abortion

Under present UK circumstances losses are between £1000 (where cows yield 6000 litres) to £1300 (where the yield is 9000 litres) per abortion.

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