COLUMNS


Most Valuable Investment in the Beef Herd

By Dr. John Comerford


Beef producers are often called upon to buy feed, minerals, equipment and other items promised as the “best investment for your farm.” The only one real investment in the farm that can always live up to the promise is the bull in the pasture. If you have a closed herd, the genes in that cow herd will come solely from the bulls you select after just a few generations.

For the beef cow-calf enterprise, the sale of a live calf is the only source of income—unless you count the sale of cull cows that did not get bred or lost a calf. The first step is having a bull available that will accomplish two things: get the cow bred when she is in heat, and provide the most pounds possible across the scales at sale time for the calf.

Getting the cow bred

If we track the cycle of events that leads to a live calf across the scales, we have to have a fertile bull with a fertile cow at the right time. Fertility in young bulls is a function of age, genetics, nutrition and other factors. The only objective method of measuring fertility is with a breeding soundness exam (BSE), which combines most of the factors involved in fertility (scrotal size, sperm concentration, sperm morphology and a physical exam of the reproductive organs) to arrive at a score that will value potential fertility. Failure to meet specific benchmarks for any of the factors results in a BSE failure. This score has been proven in the field to be very efficient in measuring bull fertility. Most central bull tests stations provide a BSE exam on bulls sold through the program. There are few veterinarians available, however, that provide an on-farm BSE.

A second factor of fertility in bulls is making sure the fertile mating can occur. Yearling bulls that are turned in with more than 15 to 20 cows will result in a costly breeding season. A yearling should not be expected to breed more than one cow per day. If we consider there will be at least one cow in heat every day in a 20-cow herd (a 21-day reproductive cycle), this is the maximum breeding herd for the young bull. It can be increased to 30 cows for the 2-year old, but should never exceed 40 cows for any bull, because a cow that has a fertile heat, but is not bred until the next heat cycle, will cost the producer about $40 per calf from lost weaning weight.

A third factor is buying the bull that has a greater chance of producing a live calf. Birth weight of calves is the single most important factor in calving difficulty, and difficult calvings result in dead calves, dead cows and/or cows that do not rebreed. Using genetic information such as EPDs (expected progeny differences) for birth weight have proven there will be fewer difficult calvings and more live calves. All breed associations publish the average EPD for birth weight in their population of bulls, so select bulls that are below breed average for birth weight EPD for breeding young cows. Keep them below breed average if heifers are to be retained in the herd from any cows because half of the genes for birth weight come from the dam.

Getting more pounds

The most expensive bull a producer can buy is the one from the sale barn with no genetic records. It is like buying a tractor to pull a six-row corn planter without looking at it or knowing the horsepower. The technology for breeding cattle is such that there is no reason to buy inferior bulls. EPDs, performance records and genetic markers are all there to use to get the most from the bull-buying decision. Consider this example of using EPDs to select two bulls:

  Bull A Bull B

Birth weight EPD 3.0 3.0
Weaning weight EPD 45 3.0
Price $2,000 $1,500

These EPDs tell us that, when bred to an average group cows, Bull A will wean calves that are 15 pounds heavier than Bull B, and both will have the same average birth weight. If we use these bulls on an average of 30 cows over four years, and wean 90 percent of the calves, we will expect Bull A to wean 1,620 more pounds of calf. At $1 per pound, that is $1,620 more value over the life of the bull, which is why the $1,500 bull is about $1,100 more expensive to own than the $2,000 bull. We actually did this comparison on a farm a few years ago, and found the difference was more like 50 pounds per calf, and a bull that could be bought for $2,000 was actually worth $5,000 to that herd. Consider, also, that bulls are “rented.” For the initial cost of $2,000 for a bull that is sold for $600 when he is culled after just four years, the cost to breed each cow for 30 cows each year is just $11.66.

Impact of Bull Selection in a Closed Herd of Beef Cows

Year Percent of genes from selected bulls
One 0
Two 0
Three 10 percent
Four 20 percent
Seven 50 percent
20 percent replacement rate in the cow herd

In the decision to buy bulls, set the goals for the herd, find bulls with the genetic information that can reach those goals and disregard bulls without known genetic value. Then, select bulls based on the breed, phenotype or color you want. It will be the most important investment you make.

Dr. John Comerford is associate professor of dairy and animal science at the Pennsylvania State University.