Artificial insemination for beef herds is easier than ever.

The days when artificial insemination was too time consuming and too costly for most beef herds appear to be over.

New products and new techniques have put the practice of heat detection on the back burner and made timed insemination much more akin to working from a cookbook—follow the directions, bake for 7 days and voila, your cow is ready for breeding.

That level of simplicity may be exaggerated, but for many cattle producers today the use of heat synchronization and artificial insemination has become routine and worthwhile.

For example, one group of Missouri-based producers with considerable AI experience is finding the practice has become a real profit maker. Many beef producers in the Missouri Show-Me Select Replacement Heifer program in southeastern Missouri have used AI successfully and profitably for years in their herds, said Roger Eakins, University of Missouri extension livestock specialist at Jackson, Mo.

In the last few years, many of these producers have found that retained ownership of their cattle through the feeding phase, plus sale of these animals through a pricing grid have more than paid for all the up-front costs of getting into AI.

Eakins cited the case of a producer in that program who sent a load of fed cattle to a major packer and was paid the average live price, despite the fact the entire load graded Choice and average yield grade 3. Eakins helped to organize a second pool of cattle headed for the U.S. Premium Beef program after he and the cattleman talked. When that load went to U.S. Premium Beef, it sold on the grid. The cattle graded 30 percent Prime and 48 percent went to Certified Angus Beef, for a price premium of $128 per head over the previous group.

Aside from the potential financial gain by use of artificial insemination, the process has become easier and more effective than in the past. The sellers of reproductive technology have spent a lot of money and research in recent years developing new products and better techniques, said David Patterson, reproductive specialist at the University of Missouri. Many of these new developments come as a result of improvements in methods to synchronize estrus and facilitate fixed-time artificial insemination in cattle.

From these improved methods a growing number of beef producers are using timed insemination and observing pregnancy rates in the range of 60 percent or higher via fixed-time AI with no estrous detection. A new study in Missouri with three university herds and one owned by MFA showed 88 percent of the cows that became pregnant by the end of the breeding season had conceived during the first 25 days of the breeding season through well-managed synchronization and AI.

Why things changed

In scientific terms, one reason methods to synchronize estrus have improved is that researchers used ultrasound to better evaluate what occurs in the ovary from one heat cycle to the next. As a result, newer methods of estrous cycle control encompass both controlling the life span of the corpus luteum and manipulation of follicular waves—an important development for more precise methods of estrous cycle control in cattle.

AI has changed from a time- and labor-intensive practice, one that required hours observing cows to detect heat, to a more schedulable event. And as such, it is creating a resurgence of interest in artificial insemination of entire cow herds. In the past, the majority of beef animals inseminated were heifers, not cows. However, while interest is growing in the United States, tremendous increases in the use of AI have been seen overseas. (See sidebar on page 10.)

Getting a handle on it

There are still two basic methods of synchronization: timed and heat-detected. The two may be combined to create a third basic protocol or method.

The traditional obstacles for producers are the great many names and significant variances in timing and product combinations for various synchronization systems.

To resolve such confusion, an effort to standardize these protocols industry wide was made last year. Four major companies in the reproductive industry met with bovine practitioners and reproductive researchers from the north central United States. The group, known as the North Central Region Bovine Reproduction Task Force, came up with standard recommended synchronization protocols for cows and heifers.

Patterson said the task force wanted to create industry standards so synchronization would be more understandable; there would be less confusion over techniques, and therefore AI would be more successful for beef producers.

Cows versus heifers

Moreover, the practice of synchronizing the estrous cycle of cows is still a bit different from synchronizing heifers, Patterson said. One difference is that timed AI isn’t quite as effective in heifers as cows. A factor contributing to this difference is that response to GnRH, the often-used follicle stimulation hormone, in heifers in many cases is less predictable than in cows.

Yet when heifers are nutritionally and physically prepared and of adequate age, they do quite well, rivaling cow synchronization in the percentage of heifers that exhibit estrus during a synchronized period.

The final effectiveness of heifer synchronization won’t quite equal that of a well-run cow program, according to research summaries, but the statistics Patterson has gathered from Missouri and elsewhere show pregnancy rates generally running from about 80 to 90 percent in a 42-day breeding season.

The case for heifers

Perhaps it should go without being said, but the primary requirements for heifers to be bred by any means are that they must be old enough and in good body condition to be sexually mature. So it is with synchronization and AI.

Further, they should be assessed as to their physiological readiness for breeding, Patterson said. As evidence, he explained that heifer pregnancy rates go up steadily as the ranking for reproductive tract score (RTS) increases. RTS is a Colorado-developed system of measuring heifer preparedness for breeding.

Missouri data using this system also shows that well-run synchronization and artificial insemination programs can equal or slightly exceed pregnancy rates for natural service on heifers.

Reproductive tract scoring should be done 6 to 8 weeks before breeding heifers, or 2 weeks before estrous synchronization, Patterson said. When more than 50 percent of the heifers have RTS scores of 4 or 5, then the synchronization process can begin.

Patterson said to begin breeding heifers 2 or 3 weeks earlier than the cow herd, and use sires with high-accuracy EPDs, particularly for birth weight or calving ease.

Lighten up

A common fear among producers new to heat synchronization and AI is an anxiety that too many of their calves will drop on the same day, overwhelming their ability to properly care for them. Not to worry, Patterson said.

Data from a wide cross-section of animals shows cows synchronized and bred as a group calve no more than 20 percent on a single day, and usually much less.

Patterson added that improvements in synchronization products and protocols have made artificial insemination “size-neutral” for beef operations, but producers still must be detail-oriented to make it work.

Part of the new technology for heat synchronization is a controlled internal drug-

releasing device (CIDR). It is inserted into the cow’s vagina and releases progesterone. In several of the synchronization protocols, the CIDR is used instead of MGA.

Use of a CIDR requires an additional pass through the chute but is more reliable because MGA intake can vary.