UNIVERSITY PARK, Pa. – New research from Penn State University suggests cross-bred beef-dairy calves may have heartier constitutions than purebreds.

Cross-bred beef-dairy calves are the result of using artificial insemination to crossbreed dairy cows with beef bulls. Some dairy farms have adopted the practice to develop an additional revenue stream, producing hybrid calves that typically have improved meat quality and higher market value compared to purebred dairy calves.

The practice had a pocket of early adopters in 2014, and the popularity of the practice has only increased with ongoing droughts in the beef industry driving the price of heifers. Melissa Cantor, assistant professor of precision dairy science in the College of Agricultural Sciences at Penn State, said that almost every dairy farm she visits has a program for beef because hybrid calves create a positive cash flow source.

Cantor’s research focuses on how diseases impact the health, performance and welfare of cattle. When her colleagues were funded to study the genetic impact of crosses at the feedlot, she joined the project to study how pneumonia impacted hybrid calves.

The study followed 143 beef-dairy calves sourced from two commercial dairy farms, with sire breeds including Simmental, Angus and Red Angus. The calves were raised in three consecutive cohorts and all cohorts were transported to a grower facility within six days postweaning and raised in one pen inside of a bedded single hoop barn until the study was completed.

“We made sure (the studied calves) had the same amount of colostrum that we would give a purebred Holstein. So, in that way, from an immune standpoint, they’re just as vulnerable to a respiratory disease event as a purebred Holstein would be,” Cantor said.

Researchers evaluated the calves for pneumonia at weaning, finding that about a quarter of the study animals had the disease. Calf weights were assessed soon after birth, at weaning or about 14 days, postweaning at about 21 days, and at about eight months.

Results of the study showed that by the age of eight months on average, hybrid calves that recovered from pneumonia achieved similar average dairy growth rate as compared to calves that never had pneumonia.

“For some reason, a lot of these calves cured themselves,” Cantor added. “I don’t understand why, but most of them didn’t need antibiotics.”

Now, Cantor and her colleagues say that the biggest research question is understanding why hybrid calves were able to recover from pneumonia without antibiotics, something that isn’t observed in purebred calves. One potential explanation is that all calves in the study were assessed for pneumonia using ultrasound. Most animals look clinically healthy but are sick. Cantor said this could be happening in Holsteins all the time, and producers are unaware. Still, she emphasized the importance of more research because it remains unclear how hybrid calves compare to purebred calves recovering from pneumonia.

The team also observed microbiome differences between calves that had pneumonia and those that did not. The differences were observed at slaughter, and researchers are still analyzing the data to understand and confirm the differences. Cantor said it’s strange to see such differences resulting from a respiratory disease that occurred at weaning.

Partnerships with other researchers have shown that early-life disease events in cattle may negatively impact other attributes than growth, Cantor noted.

“Our next step in this research is (asking questions like) are these liver abscesses we see in beef on dairy cattle linked at all to early-life disease events like pneumonia? What carcass characteristics are compromised by early life pneumonia?” she said. “We’re doing a lot more digging, and we have a grant with the Pennsylvania Department of Agriculture to answer some of those questions.”