When it comes to autumn breeding, a question farmers regularly ask is what is the cost difference between using AI and a stock bull?

While a direct cost can be placed on AI and running a stock bull, there are factors that are harder to place a value on.

These include the cost of the herd sire, safety issues with a stock bull, selecting the best genetics within breeds through AI and matching different sires to certain cows.

But for the sake of the opening question, let’s try and compare the cost of using AI in an autumn-calving suckler herd with natural service.

Example herd

The example assumes a herd of 30 cows calving over August and September with 100% use of AI.

In most cases, suckler herds repeatedly using AI will have a fertile cows, as problem breeders are easily identified and rarely tolerated. Although, this is also the case in well-managed herds using stock bulls.

As cows are fertile, conception rates to first service are taken as 80%, with second service also getting 80% success. AI is carried out by a technician at a cost of €15 for the first insemination. Any repeat inseminations incur the cost of the straw only. Straws are also priced at €15 to reflect a high-index bull with good semen availability.

Service costs

Taking 30 cows served at 80% conception rates, there should be 24 cows in-calf to first service. The six animals that repeat get a second service. At 80% conception, a further five animals will be in-calf.

In total, there are 36 inseminations. The first 30 inseminations cost €30 each (€15 for the technician and €15 per straw).

The six repeat services cost €15 per insemination for the straw. Total insemination costs therefore come to €990 for the full herd.

Natural service

To allow for a fair comparison, at the outlined price for straws, the choice of AI is an animal of high genetic merit.

Therefore, the example assumes the farmer buys a high-index stock bull at €4,000 to try to produce weanlings of a similar quality.

Assuming the bull has a cull value of €1,500 and is retained for five years of breeding, the bull has an annual depreciation cost of €500 per year to cover 30 cows.


However, this does not mean the bull is cheaper than using AI. The bull has to be fed and maintained every year.

The example assumes the bull is housed on 1 October, with a breeding period from 15 October to 15 December, during which similar conception rates are achieved as cows are managed under the same conditions as those served to AI.

Feed costs

The bull is fed 50kg of silage (€25/t) and 2kg/day of concentrate (€310/t) from housing until 15 December, costing €142.

From 16 December to 30 April, the bull is offered a forage-only diet, averaging 50kg/day of silage and costing €170.

From 1 May to 30 September, the bull is grazed at a cost of €15/month, or €75 for the outlined period. Vet and miscellaneous costs of €50 are factored in also. This brings the maintenance costs for the bull to €437/year, and the cost of running the bull for 30 cows to €937/year.

Based on the outlined example, using the stock is slightly more cost effective.


However, there are a multitude of other factors to bear in mind. A cheaper stock bull will greatly reduce the costs for using natural service.

But it is unlikely that such a bull will produce high-value weanlings for sale. This will leave a significant differential in sales income when compared to the progeny from a high genetic merit sire.

On the flip side, DIY inseminations will eliminate €450 from the cost of using AI in the example herd, making the economics tip in its favour using the example costings.

The example also assumes that housing is set up for AI, as well as the farmer having time for heat detection. This may not be possible, in which case natural service is the best option.

Natural service also costs less if the stock bull will be used to serve spring-calving cows on farm.

Ultimately, the purpose of the example is to take the time to work out which breeding method is the most cost-effective option for your suckler herd.

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