Isa Hosts Annual Beefmaster Bull Sale

Every October Isa Beefmasters hosts the largest one-brand bull sale in the Beefmaster breed. The sale is held the first Saturday in October, and it features approximately 110 L Bar Beefmaster bulls. These bulls represent the top 33% of bull calves weaned. You can buy the absolute best bulls we produce!

Buyers arrive from across the U.S., Mexico, and South America to attend this truly international event. Please call (325) 656 9126 to learn more.

Isa’s 64th Beefmaster Bull Sale—Oct. 4, 2025


Isa’s Performance Test

Principles developed by Tom Lasater beginning in 1936 guide our unique peer-group performance test. We adhere strictly to the Six Essentials—Fertility, Weight, Conformation, Milk Production, Hardiness and Disposition. When Tom Lasater began weighing his bull calves more than 80 years ago, he did so in a time when cattle were being sold by the head, and he was called a revolutionary genius, a crackpot and everything in between.

Tom saw that weaning weights and a defined breeding season of 90 days or less were two extremely simple ways to identify high performers and low performers and, by doing so, enforce the Six Essentials. Today, weighing calves is the cornerstone of any relevant breeding program and should be as routine as turning out bulls.

We take our heritage of performance testing very seriously, and it shows in our cattle and in the performance information backing them up. The data we provide, combined with careful appraisal, has proven to be an extremely accurate way to select the best bulls in all price ranges. Only our extreme best bulls are sold. Not a single bull is topped before the sale!


Preparing Bulls for the Sale

At weaning, the bulls are brought together and spend the first eight months of the Isa Bull Performance Test under range conditions, growing frame and developing the athleticism so critical to their performance in difficult environments.

We then finish with a 50-day Gain Test on a low-energy ration, which is scientifically designed to show genetic differences in gainability without getting them too fat. Our customers from all parts of the world will tell you these bulls hold up when you get them home.


Selecting Your Bulls at the Sale

We feel our sale format is the most user-friendly in the industry. We sell the two age groups—coming twos and two-year-old bulls—in roughly descending order of quality. The bulls are penned and cataloged in sale order, which means that the buyer can target the section of the sale corresponding to their budget without jumping from page to page in the catalog. We handpick the first 45 bulls as suitable for use in the registered herds.

As the sale progresses, the price goes down, which means a volume buyer can “average down” during the event. The bulls are excellent quality throughout the sale, so you have only to mark off those that do not suit your needs, and then let your target average price determine which bulls you buy. The biggest mistakes buyers make are not starting to buy early in the sale and not selecting enough bulls from which to buy. Be sure to look at the bulls from the bottom up.


Isa’s Unconditional Guarantee

Many Isa customers have told us how much they appreciate the simplicity of the sale, which allows them to focus on the business at hand. All of the bulls have a complete health background, are fertility-tested and ready for service. And they are backed up by the Isa guarantee. While others say their bulls are guaranteed, we back it up.


Wealth of Information in Sale Catalog

Isa Beefmasters gathers all of the performance data in the catalog, and each set of measurements is taken in a one-day period. This enables all bulls to have an equal chance to show their potential. We believe that the off-test weight, ribeye and scrotal measurements are key. We have measured over 5,000 ribeyes.

We also list each bull’s dam in the catalog, and the first digit of her number is her year of birth. We believe that age of dam is very important and is basic to our selection process. An outstanding son of a 2- or 3-year-old dam shows exceptional potential. All cows in our herd have a calf every single year from the time she turns two, so the outstanding son of an older cow carries longevity in his genes, one of the most important economic traits.We now also list the sires in our catalog. Isa has made a heavy investment in DNA testing ($30 per calf) to identify the sires. This enables us to track what the bulls are doing, while still putting selection pressure on libido by using multi-sire herds. The use of multi-sire herds and requiring heifers to calve at 24 months sets the Lasater genetics apart from all other cattle families.


Quality of Bulls Validates Test

The proof of the validity of the Isa Beefmasters Performance Test lies on the great semen bulls that have come out of this program: L Bar Habanero, Escalade, L Bar En Fuego, Total Package, L Bar 0324, L Bar 5502, L Bar 3432, L Bar Automatic, L Bar Essential, L Bar Inevitable, L Bar 3100, L Bar 4401, L Bar 2474, L Bar 8443, L Bar 9239, L Bar 1175, L Bar 1167, L Bar 6171, L Bar 7303, L Bar 7499, and L Bar 8419.

Isa Beefmasters boasts many trait leaders in the herd: L Bar En Fuego tops both scrotal circumference and carcass IMF EPDs. L Bar Habanero ranks in the top 1% of scrotal circumference EPD, while L Bar Inevitable also earns top marks for both milk and carcass IMF EPDs. L Bar 5502 is in the top 15 for weaning weight, yearling weight, and scrotal circumference EPDs, making L Bar 5502 the only triple trait leader in the Beefmaster breed!

We are very proud to sell top-quality, tough, well grown-out bulls in a user-friendly format to professional cattlemen, and we provide complete after-the-sale marketing assistance to those desiring it.


Frozen Genetics Ship Worldwide

In addition, Isa Beefmasters sells semen and embryos around the world. Customers throughout the US, Central America, South America, southern Africa and Thailand have found tremendous success using our genetics. Click here for more info.