AMES, Iowa – A two-year study by Iowa State University researchers closely examined diet effects on Angus and Holstein crossbred calves, specifically evaluating early calf diet options and their long-term impacts on animal health and carcass characteristics.

Garland Dahlke, Iowa State University’s Iowa Beef Center research scientist, said the study focused on short- and longer-term effects of different diets in the first five months of life. He shared information from the project with attendees at the 2025 Feedlot Forum, Jan. 14, in Sioux Center, Iowa.

“We primarily looked at calf starter and the level of non-structural carbohydrate concentration (or NCS;  non-structural carbohydrates contain a reduced amount of easily-digestible sugars and starches) and the effect this may have on the rest of the calf’s life and subsequent carcass composition,” he said. “Three groups of Angus x Holstein (crossbred) steer calves were followed during the two-year project.”

For the first stage, from birth to weaning at approximately two months of age, the calves were divided into two calf starter treatments: one fed a higher NSC (30 percent), and one fed a moderate level (17 percent), he said.

From age two through five months, calves from each of the initial two groups were split into a similar pelleted diet to the initial 30 percent NSC diet versus a total mixed ration. All calves in this stage were in group housing at the Iowa State University Dairy, and then at the Iowa State University Beef Nutrition farm near Ames, he added.

After completing the wean-to-grower phase at approximately 850 pounds, calves were moved to the Iowa State University Armstrong Research Farm near Lewis. All received the same ration from five months of age until finish, he said.

He said these early diet treatments had a significant impact on the incidence of liver abscess. Those calves receiving the moderate NSC starter, followed by a fairly energy-and-protein-dense total mixed ration, had a significantly lower incidence of both liver abscesses, as well as rumen and gastrointestinal lesions (a region in an organ or tissue which has suffered damage through injury or disease, such as a wound, ulcer, abscess or tumor) when compared to calves on the higher NSC level.

He said these calves also maintained on this NSC level beyond the calf starter phase, or even those moved to the total mixed ration after the calf starter phase.

“Feedlot performance and carcass results were not significant between treatments when calves were fed to 1,450 pounds of final live weight,” he said. “There was a trend beginning to appear where those animals receiving the moderate NSC and transitioned to the total mixed ration were performing better later in life, and some significance may appear if these calves were fed until 1,600 pounds.

“The young age of these calves would tend to indicate that rumen development is rudimentary, and may be enhanced by the diet composition,” he added. “Based on these results and the impact early nutrition has over the long run, a next logical step would be to focus attention on composition of the initial calf starter, intentionally including more digestible fiber sources, and better profile of amino acids.”

Andrew P. Griffith, University of Tennessee professor of agricultural and resource economics, said this research is much-needed. “With the advent of beef on dairy cross the past several years, this study looked to evaluate a major issue influencing the profitability of these animals,” he said.

“I cannot say it is the most economically important issue as something else may come to the forefront, but liver abscesses have been one of the hitches in this production model,” he added. “I guess I am wishing they would have carried these animals to heavier weights, given the comment they were starting to see some difference in feed efficiency.”

He said, “The pros of this (study) are primarily to the dairy producer who is now turning their male calves into a profit center instead of just breeding the cow to produce a calf so they can get another fresh cow to be milked. The Holstein steer has always been known for its consistency as far as beef production. With the beef on dairy cross, there is now added value to each carcass as it better fits the box most consumers are looking to consume from.

“From the liver abscess standpoint, there is a tremendous cost to liver abscesses as an abscessed liver must be discarded generally results in trim losses on the carcass, and as was noted in the study, animals may become less efficient from a feed conversion standpoint,” he added. “In this study, they cannot say there was a difference in feed efficiency and growth, but one could surmise that damage to organs will likely have an impact on an animal’s growth at some point.”

Grant Dewell, Iowa State beef extension veterinarian, said, “Genetic identification of sires that are compatible with dairy cattle has led to calves with enhanced growth and carcass traits that are more desirable. Traditional calf starter programs did not perform as well as expected, and initially increased levels of liver abscesses were observed in these beef-dairy cross steers.

“Overall, starting calves with a more moderate in terms of carbohydrate composition resulted in decreased incidence of liver abscesses and gastrointestinal lesions,” he added. “This project demonstrates the importance of starting calves to appropriately develop their gastrointestinal system, and what the long-term impact of that development is throughout the life of the calf.”