New research by Penn State University, has found that dairy-beef crossbred calves are hardier than their purebred counterparts, demonstrating faster recovery rates from pneumonia and similar growth rates to calves that have never had the disease.
The study, which is reportedly the first of its kind to investigate the long-term effects of pneumonia in beef-on-dairy cattle growth, challenges previous assumptions that infections would impede the post recovery growth rates of infected animals.
Scientists studied 143 crossbred calves with evidence of the disease at weaning, weighing them at various intervals, including at birth, at weaning, post weaning at 21 days, and at eight months old, to assess their growth performance and the impact of pathogens in the calves’ lungs.
The researchers reported that pneumonia observed in beef-dairy hybrids, only compromised growth rates for approximately three weeks until they returned to normal performance.
In addition to this, the dairy-beef crossbred calves which were diagnosed with pneumonia, exhibited compensatory growth when compared to calves that had never been infected, suggesting that the illness has no long-term performance implications.
It also determined that lung pathogens were not associated with growth performance, and that average daily growth was similar among all calves by about eight months-of-age, irrespective of whether they were impacted by the disease or not.
Recovery of crossbred calves
The researchers also concluded that the calves studied recovered without antibiotics, which could help reduce antimicrobial resistance (AMR) in cattle and may be of particular note for the organic dairy industry.
Co-author, Melissa Cantor, explained the impact of the results: “Our study, which aimed to understand the impact of pneumonia on growth and the potential for self-healing in calves, highlighted that beef-on-dairy crosses often recover from pneumonia without antibiotics, unlike purebred Holstein dairy calves.
“We think this is at least partially attributed to hybrid vigour, the phenomenon by which a progeny exhibits superiority over its parents in traits such as growth rate and productivity.”
The research, which was published in the Journal of Dairy Science, was spearheaded by the Department of Animal Science at Penn State, which hopes it will help dairy farmers to make more informed decisions around breeding.
“This research was aimed at understanding the long-term effects of pneumonia and the economic implications of crossbreeding,” Cantor added.
“We’ve had really high inflation, particularly in the dairy industry, where the cost of raising purebred dairy replacements has grown astronomically.
“Adding the beef-on-dairy hybrid sideline to their businesses has helped them, but financial constraints dictate that dairy farmers must be selective about which animals they keep. They need to be sure the practice makes sense for them economically,” Cantor said.
