By Larry Stalcup Contributing Editor
With herd rebuilding still at a snail’s pace, feedyards will likely see more beef-on-dairy cattle in their pens the next few years. To help beef-on-dairy cattle approach or exceed the performance of conventional beef cattle, zinc and other trace minerals are essential in rations to provide the most efficient nutritional packages for better gains, quality and overall animal health.
After hitting 9 to 10 percent earlier this year, beef-on-dairy numbers might reach 14 to 15 percent of total fed-cattle slaughter by 2026, according to CattleFax data. That’s nearly 4 million or more cattle per year. Alex Thompson, Ph.D., Zinpro feedlot business manager, says it’s difficult to expect herd numbers to return to where they were when cattle supplies began shrinking several years ago.
“Every time we dip in cow inventory, we never return to previous cycle highs,” he says. “We’re finally seeing beef-on-dairy models that show how these crosses can work well to help replace some of those lost feeder calf numbers.”
Thompson, who studied under Brad Johnson at Texas Tech University, has spent nearly eight years working with feedyard nutritionists and managers to develop mineral programs that address the needs of their operations. Due to the significance of beef-on-dairy calves to the feeding industry, Zinpro’s most recent research sought to answer questions regarding the impact of elevated zinc supplementation on animal health and performance of this growing population.
In spring 2022, there were 5,249 dairy-beef steers with an average weight of about 360 lbs. enrolled in a study at Simplot Livestock Co. in Grand View, Idaho. All cattle received a basal ration with 90 ppm supplemental zinc from zinc sulfate. However, a treatment group received an additional 60 ppm of supplemental zinc from Zinpro Availa Zn throughout the 384-day duration of the study.
Results showed improved average daily gain in calves that received supplemental Zinpro Availa Zn vs. controls (3.07 lbs. per day vs. 3.02 lbs. per day, respectively). They achieved this with a slight reduction in dry-matter intake, resulting in a 2.3 percent improvement in feed efficiency (P < 0.01) and a 21-lb. advantage in final bodyweight.
“This response translated to 12 lbs. of additional hot-carcass weight in the treatment group compared to those calves receiving zinc sulfate alone,” Thompson says.
The study also reported additional benefits in carcass quality and animal health. Zinpro Availa Zn supplementation tended to improve the proportion of animals that graded USDA Prime and Choice.
“It also resulted in a 9 percent reduction in the incidence of severe liver abscesses,” Thompson says, adding that treated cattle also had a reduction in overall morbidity, and total mortality was reduced by 9 percent compared to the control population as well.
“This study demonstrates the benefits of continuous Zinpro Availa Zn supplementation, even at extended days on feed,” Thompson says. “While we observed improvements in animal health and carcass quality, the performance advantages associated with this elevated feeding rate continue to drive significant value for producers. Zinpro Availa Zn provided a net return of more than $25 per head based on the 12 lbs. of additional carcass weight alone.”
Thompson points out that these results “don’t exist in a vacuum,” and references Zinpro’s larger body of feedlot research. A pooled analysis of trials conducted between 2001 and 2016 reported similar responses when Zinpro Performance Minerals were used in finishing rations.
More than 13,000 head were evaluated across nine university and commercial trials, and cattle that received 60 ppm supplemental zinc from Zinpro yielded 10 lbs. more carcass weight than sulfate controls.
Other Zinpro research has often addressed the importance of zinc and other trace minerals in managing foot rot, digital dermatitis, heat stress, BRD and other health-related challenges. However, Thompson emphasizes the most recent beef-on-dairy study is further evidence for the need of elevated zinc to help maximize both live and carcass performance in fed cattle.
Thompson notes that in a typical trace mineral program, Zinpro Availa 4 is recommended in the receiving period. From there on, Zinpro Availa Zn is provided for the remainder of the feeding period. For cattle that are pulled and treated, Zinpro ProFusion Drench can be used to provide a multi-day supply of essential trace minerals and other nutrients when those animals are likely to go off feed.
“Despite the application of technologies such as new implants or beta-agonists, we continue to show time and time again that zinc is essential to maximize cattle performance and health,” Thompson says.
For more on the Zinpro beef-on-dairy research, visit zinpro.com/wp-content/uploads/2024/04/B-5096_Availa-Zn_5c.pdf.
LIVER ABSCESS QUESTIONS
While more beef-on-dairy feeders are expected to fill feedyard pens, profit-robbing liver abscesses will remain a key problem in feeding beef-on-dairy crosses along with conventional cattle.
Liver abscesses often occur when cattle are fed a high-energy, low-roughage diet in order to reach the desired USDA Quality Grades.
“Liver abscess issues are among the reasons we conducted the large beef-on-dairy cross study,” says Dr. Alex Thompson with Zinpro. “We saw a 10 percent reduction in severe liver abscesses compared to the control group (14.54 percent vs. 15.95 percent).”
He contends that dairy-influenced cattle may receive a disproportionate number of discounts from packers. “In the Imperial Valley [where Holsteins make up the majority of cattle on feed], liver abscess incidence typically runs below 20 percent,” Thompson says. “But packers have previously applied a blanket discount to this population because they may run at a higher prevalence on a national scale.
“It’s unfair that producers are docked simply because their cattle are dairy influenced.”
The West Texas A&M University Animal Science Department in Canyon has studied the cause of liver abscesses since the 1970s. Ty Lawrence, Ph.D., WT’s Caviness Davis Distinguished Chair in Meat Science and professor of animal science, is among scientists from WT, USDA’s Agricultural Research Service, Texas Tech University and Kansas State University who recently published a study for the Journal of Animal Science that looks at what triggers for liver abscesses in cattle.
“A reliable and repeatable model will allow beef industry scientists to apply treatment strategies to mitigate liver abscess frequency and severity,” Lawrence says.
“After decades of studies, researchers haven’t found an accurate way to predict nor diagnose liver abscesses, because of the complexity of the disease,” adds Rand Broadway, research scientist with ARS’s Livestock Issues Research Unit.
“Our study is a huge collaborative effort between USDA and academic partners to develop a liver abscess model in cattle that can help us better understand how liver abscess formation begins. We are constantly learning about the causes and development of these abscesses.”
For more on the liver abscess study, visit https://academic.oup.com/jas/article/doi/10.1093/jas/skae046/7623335?login=false.
