How US Angus breeder makes more beef from smaller cows

Performance recording and national bull tests have helped one American Angus breeder achieve a lower slaughter age while having smaller, more compact cattle.

Bulls reach their 635kg slaughter weight 15-20 days earlier at Stewart Select Angus, Greensburg, Indiana, where the Stewart family performance records 200 pedigree Angus cows.

By paying to have their bulls feedlot tested and paying close attention to Aberdeen Angus Association indexes, the Stewarts have seen growth rates increase while birthweights have decreased by 2.25kg and cow size is 50-60kg lighter. 

See also: Efficient ranching: Smaller cows build big returns in USA

The Stewarts sell 80 breeding bulls privately each year, as well as a number of heifers and mature cows around four to six years old, and fatten 15 steers.

Now bull calf weights average 38kg and heifer calves average 35kg. Mature cows size has decreased slightly to 657kg.

“We used to have a show-ring mentality back in the 1990s,” explains Andrew Stewart, who started genotyping his herd in 2013. “But we switched to being commercially focused and data driven.”

Importantly, this hasn’t had a negative effect on daily liveweight gain (DLWG), which over the past three years has increased 9g.

Stewart Select Angus

  • 200-pure Aberdeen Angus herd
  • Performance recorded for over 20 years
  • 80 bulls sold each year
  • 105ha of pasture
  • 1,420ha growing maize, soybeans and wheat
  • Processing and treating seeds for Monsanto
  • Calving indoors between December and March, starting with heifers
  • Cattle rotationally grazed and stocked at 1.25-1.5units/acre
  • Grazing from around April 15 to November 1 

Bull tests

Each year a batch of 10 bulls head to Montana to the Midland Bull Test (MBT), one of the most prestigious bull testing and marketing facilities in America.

A further 10 bulls head to the Indiana Beef Evaluation Programme (IBEP). Mr Stewart believes the tests are fair and objective and allow a comparison between breeders.

The tests receive bulls in the autumn and monitor the growth of bulls in identical conditions and on the same feed before holding an April sale at the test yards. 

A number of bulls are reared and recorded at home and the bottom 20% are castrated and finished on corn gluten pellets, soybean hull pellets and a hormone implant to a weight of 635kg liveweight at 14 months old. They are marketed through the Certified Angus Beef Brand scheme for a 20p/kg premium.

The MBT and IBEP tests receive three sire groups from the Stewarts and assess bulls’ structural soundness and health, and monitor growth on a mid-energy finishing ration for 120 days to emulate commercial feeding.

It’s paramount for both tests that bulls are creep-fed, or what Mr Stewart terms as “bunk broke”, have birthweights of below 41.2kg and are vaccinated 3-4 weeks prior to shipment.

“Starting on 1 July we start limiting creep feed to them,” says Mr Stewart, who starts off at 45g and builds up to 1.8kg at weaning.

Bulls are fed a 16.53% crude protein ration of two-thirds maize and one-sixth corn gluten pellets and soybean pellets at 74.55 total digestible nutrients.

Before shipment to the test centres, bulls are weaned and fed a high fibre ration of chopped alfalfa baleage and corn silage through a mixer before going to MBT at around 600kg.

Average DLWGs are recorded and reported after 60, 90 and 120 days, with all MBT bulls needing to hit DLWGs of 1.13kg a head/day initially and latterly 1.1247kg/day.

Bulls not hitting this gain are not included in the residual feed intake (RFI) reports, which are published ahead of the sale.  

Bulls are catalogued by IBEP and MBT and sold, with some bidders staying at home and assessing figures online. 

IBEP bulls are sold with all estimated progeny differences (EPDs) displayed, as well as average daily gain figures, dam information and credentials for carcass quality. In addition to this information, MBT bulls come with a rating for RFI. 

Selection and breeding tests

  • Midland Bull Test: Running since 1962. Costs £620 a bull from mid-September to early April with 10% sale commission. Operating calibrated Growsafe feed bunks calculating RFI at 0, 25 and 70 day intervals. This allows producers to find the bulls that gain quickly and cheaply. Efficient animals eat less than expected for every kg of gain and have a low or negative RFI.
  • Indiana Beef Evaluation Programme: Costs £580 a bull from early October to mid-April with a 5% sale commission. Bulls fed 55% wheat silage, 22% wheat grain, 20% distillers’ dried grains and solubles (DDGS) and 3% balancer. A summer and winter test is performed over 125 days.
  • Association genotyping i50K: The Stewarts have been genotyping their herd since 2013. i50k is a genetic DNA test developed from estimated breeding values (EBVs) supplied by Angus Australia. It evaluates genetic potential across 22 “economically important traits”. The service claims to be equivalent to 10-20 progeny of that animal.


Test results

Growsafe feed bunks are used at MBT, which means the Stewarts not only know which bulls are growing the fastest but which are achieving this while eating the least amount of feed.

The bunks track each bull via an electronic identification ear tag and measure feed intake. The system creates RFI and Dry Matter Intake values for sires.

At IBEP, the bulls are not fed through Growsafe feed bunks but the Stewarts see a lot of value in both tests and believe that without them they could not sell the 80 bulls they currently do each year.

“We could probably still justify having the cattle without the tests but we definitely wouldn’t have the bulls we raised in artificially inseminated stud lineups like we currently do,” admits Mr Stewart.

“It’s nice when you have numbers, rather than just rosettes, to back up your operation and your cattle to people buying your breeding stock.”

Each year MBT stock have their post weaning DLWGs published, which this year hit 1.4-1.5kg.

And while 10% of the Stewarts’ bulls may not make the weight gain required, some of the cattle that do have been very high achievers, winning awards for feedlot performance.

“Some just fall short of the gain requirements,” Mr Stewart explains. “They either get sick or just don’t perform as well.

“These tests allow us to compare our bulls against other breeders to verify that we still have good quality genetics. This also allows me to market my bulls in a slightly different market.”

Andrew Stewart

Breeding policy

The herd was genotyped in 2013 and now each crop of calves have DNA samples taken in the spring.

Either blood or hair samples can be taken, explains Mr Stewart, with results from the i50K testing helping the Stewarts decide whether a female should enter the herd, be marketed based upon her genetic attributes or used as a donor female.

Around 85% of cows are artificially inseminated or receive an embryo from a donor. Heifers are synchronised with melengestrol acetate and prostaglandin, as well as some recipients and the last 20 cows that hadn’t shown heat.

Bulls are selected on their ranking in the $/W (weaned calf value) index, as this is the most important index for many Select Sire customers who sell weaned calves as stores.

Attention is also paid to $/B (beef value) – more of a terminal index factoring in post weaning growth and carcass value – and bulls must be in the top 50% of this index as well as the marbling EPD.

Cows are evaluated on the weights of calves they wean through their life and if they fall to 96% below a herd average of 100% then they are culled.

Cows are also culled based on assisted birth, explains Mr Stewart. “We watch calving ease closely and now we are at the stage when most cows have the calf by themselves even if their calf is a little big.”

A docility score is also given to all animals (1-6), with temperament being a culling issue.

Behaviour is particularly closely monitored at calving and also around the crush, with Association guidelines given as to how cattle leave the crush as to whether they are very docile (1) or aggressive and dangerous (5-6).

Breeding results

With bull tests assessing the farm’s feedlot ability and strict culling practices at home, Mr Stewart can be sure the herd is improving both maternally and terminally.

“Our weaning weights have improved slightly and our ribeye and marbling EPD figures have increased,” he adds. “Calving ease and birthweight have definitely improved and, because a live calf is worth a lot more than a dead one, our customers have benefited from this greatly.”

Average Select Sires bull prices tend to be around £3,000 for a 13-16-month-old sire. However, some popular lines have sold for over £25,000.