Growing Beef Newsletter
May 2025, Volume 15, Issue 11
Iowa Beef on Dairy Research Update:
Evaluating Impact of Early Life Nutrition on Finishing Phase Performance and Carcass Traits
Denise Schwab, ISU extension beef specialist
Beef on dairy has become a hot topic in the beef industry in the last few years, but in Iowa, it has been discussed for more than a decade. When major packers stopped purchasing fed dairy cattle, we were encouraging dairy farmers to identify and breed their lower-end cows to beef bulls to produce a crossbred calf that better fit into the beef market. While some of those first crossbred steers failed to meet the industry’s expectations, times have changed, and sire selection to fit this niche in the industry has improved significantly. Thanks to funding from the Iowa Beef Industry Council and the Iowa Beef Checkoff, we recently completed a 2 ½-year project studying beef on dairy steers.
The objective of our study was to examine how early-life nutrition, specifically looking at the level of starch or fiber in the diet, impacted performance later in life. One hundred twenty day-old beef-dairy steers were purchased from three producers and fed either a high-starch or low-starch starter ration for about 60 days. Steers were then weaned and moved to a receiving trial for another 60 days, where they were fed either a pelleted ration or a forage-based TMR ration. At the end of the 60-day receiving trial, they were fed a common growing TMR ration for 140 days. Then, steers were moved to a finishing yard and fed a common finishing diet for another 200 days. Calves were on an individual feed monitoring system throughout the project, so individual daily feed consumption was measured.
In the calf nursery stage, the high starch calves ate significantly more grain and had a slight advantage in weaning weight compared to low starch fed calves (Table 1).
In the receiving trial, there was a significant difference in feed intake, daily gain, and ending weight based on the diet, with the pellet-fed calves consuming almost double what the TMR calves ate and weighing more at the end of the 60-day trial. We suspect some of this is due to the change in the feed form (pellets vs TMR) because of the novelty of the TMR diet, the nutrient density, and the change from individual animal housing to small group housing, as well as bunk access limitations associated with only one animal being able to eat at a time in the individual feed intake system. A month after the receiving trial ended, the weight difference had narrowed and there were no performance differences between groups by the end of the grower phase (about 260 days of age).
There were also no differences in intake or daily gain in the finishing phase. However, there was a slightly different growth curve for the calves that were on the low-starch starter and TMR receiving trial. These calves were still increasing in daily feed intake and growth as the other calves were starting to slow down. Some of this may be due to compensatory gain following the receiving trial, but we speculate some may also be due to a healthier rumen in the later finishing period, which is supported by the lower number of condemned rumens and liver abscesses.
All calves were marketed at about 465 days of age. Steers graded 15% Prime and 66% CAB, 15% low Choice and 4% Select. While there was no difference in the quality grade, yield grade, or carcass weights between groups, the low-starch TMR group had slightly heavier carcass weight and 20 percent fewer liver abscesses and rumen condemnations. Beef on dairy steers in this project only averaged 19 percent liver abscesses, which is well below other reports of beef on dairy steers.
The biggest impact from a carcass merit and gain perspective was from multiple treatments for respiratory issues. Calves that were treated two or more times had a significantly lower daily gain in the finishing phase, resulting in a 49-lb lighter ending weight and a 29-lb lighter carcass weight, and returned $91 less compared to non-treated animals.
When combining the slight differences in feed intake, feed efficiency, and increased weights, the LS-TMR group had numerically higher carcass value. The HS-TMR group had numerically greater economic returns.
More research in this area is needed to further expound on the differences we saw and to better predict a feeding program to optimize growth and minimize loss of carcass value. Details on the project are available from Schwab at dchwab@iastate.edu.
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