Is artificial insemination better than natural service?

Artificial insemination can put more money in your pockets, but there are several factors to consider

This article has been edited and condensed. For the full article, including price and financial details as well as additional resources, go to the blog on the Beef Cattle Research Council website).

As the breeding season approaches, some producers will use artificial insemination (AI) and estrous synchronization in their breeding herd.

But others won’t because of the extra time, labour, and management required in an AI program; the perceived costs; or because they are unaware of the potential advantages.

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This article compares the costs and benefits of fixed-time AI and natural service, and how recent changes in breeding bull and butcher bull prices affect the cost of breeding programs. It will also look at a recent study that addresses the question of how many cleanup bulls are needed in a fixed-time AI program.

Compared to natural service, an obvious potential advantage of fixed-time AI is to have more calves born in the first 21 days of the calving season, which allows producers to market larger, more uniform groups of calves. Some studies have shown as much as a 10- to 17-day calf age advantage and 20 to 44 pounds more per calf at weaning as a result of estrous synchronization. Despite the extra costs, a fixed-time AI is estimated to have a net benefit of $11,110 for a 40-cow herd compared to natural service because of improved conception and wean rates, as well as heavier weaning weights.

Early calving as a result of AI may also affect the productive longevity of the cows. A 2014 study of 2,195 cattle showed that early-calving heifers remained in the herd 5.1 years on average, compared to only 3.9 years for heifers that calved after the first 21 days of the calving season.

In another group of 16,549 cattle, heifers that calved in the first 21 days, second 21 days, and later had an average longevity of 8.2, 7.6, and 7.2 years respectively.

With increased longevity, early-calving heifers can produce at least one more calf in their lifetime, compared to late-calving ones. The net return of an early-calving cow with six calves is estimated to be eight per cent higher (or $132/cow) than a late-calving cow that delivers a total of five calves during her lifespan (using the 10-year average calf price of $1.80/cwt, a weaning weight of 550 pounds, and annual maintenance costs of $730/cow, but excluding the potential increase in revenue due to heavier weaning weights).

Despite the benefits, only 18 per cent of western Canadian producers use artificial insemination and 11.3 per cent use estrus synchronization, according to the 2014 Western Canadian Cow-Calf Survey.

Low adoption rates may be due to several reasons.

Compared to natural breeding, AI requires more intense knowledge and management as well as increased investment in labour, facilities, equipment, semen, estrous synchronization drugs, and animal handling. Hurdles include limited time, labour, and availability of land. Cattle need to be near handling facilities for AI, which is a significant hurdle for producers with multiple breeding pastures spread out over a large area.

There is also uncertainty around the quality of semen purchased. There is a wide range in price, with no guarantee that higher-priced semen comes from high-quality animals. It is recommended that semen be examined before use or purchased from a reputable source and properly handled (including storage and thawing).

Bull prices have fallen in Alberta and Saskatchewan (from a 2015-16 peak of $5,500 to $8,000/bull to $4,500 to $6,500 in 2017-18) but some of those savings could be lost if butcher bull value moves lower at the end of the bull’s useful life. Depreciation costs for bulls increased from $2,400 to $2,800 during the 2015-17 period of the study.

Depending on the protocol employed, fixed-timed AI, semen, additional labour/infrastructure, and cleanup bulls have been estimated to cost $10 to $20 more per bred female than natural service. Although fixed-time AI could have a higher cost per bred female than natural breeding, keep overall goals in mind, and compare the benefits of AI (cow longevity, faster genetic improvement, and heavier weaning weights) against the higher costs to determine the best options for your operation.

The recent decline in breeding bull prices appears to favour the use of natural breeding over AI, but it should be remembered that bull prices can also affect the cost of an AI program due to the use of cleanup bulls. As cleanup bulls are expected to breed 40 to 50 per cent of females in a short period of time, they need to be physically fit and ideally their genetic makeup should be comparable to the AI sires. One study put the cost of cleanup bulls at $42 per cow (based on the assumption of a 50 per cent conception with AI), which accounted for about 30 per cent of the total cost of fixed-time artificial insemination at $130/cow.

A concern regarding cleanup bulls is that more bulls are needed to cover the synchronized females that did not become pregnant from AI because these females will return to estrus around the same time as each other. If the same bull-female ratio is needed in an AI program as natural breeding, the estimated cost of AI would increase significantly.

But is this concern valid? How many cleanup bulls are needed after estrus synchronization and AI?

A recent study provides a preliminary answer to this question.

The study summarized data from published studies reporting AI and final pregnancy rates, and the bull-to-female ratio, and found that final pregnancy rates following estrus synchronization and AI were similar for different bull-to-female ratios. One cleanup bull per 20 females had similar results as one bull per 60 females. Bull age is an important factor to consider as experienced bulls are more efficient breeders.

While the study provides evidence that fewer bulls are needed in an AI program compared to natural service, there is a lot of variation in terms of the optimum cleanup bull-to-female ratio depending on the efficiency of the bull, pasture size and terrain, the length of the breeding season, and so on. For example, operations with larger, more rugged pastures may demand more cleanup bulls.

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