Exploring the bovine uterine microbiome and impacts on calf production

With two intertwined projects funded by the U.S. Department of Agriculture for $1 million, Klibs Galvão, D.V.M., Ph.D., is using unique, integrative approaches to investigate better ways of understanding the bovine uterine microbiome and its impacts on calf production.

A professor of food animal reproduction and medicine in the college’s department of large animal clinical sciences, Galvão received a three-year USDA grant in 2019 to study what causes metritis, an acute inflammatory disease of the uterine lining in dairy cows. Metritis affects approximately 20% of postpartum dairy cows and has marked welfare, health, production, reproduction and economic consequences to the individual animal and the herd.

“Although the association of individual minerals or blood and microbial metabolites with immune function and risk of metritis have been studied, the important question of how the blood and microbial/uterine whole metabolome affects the immune system of the uterus and the risk of metritis has not been addressed,” Galvão said. “This knowledge is critical for understanding why some cows develop metritis and some do not.”

In a second three-year project funded in 2021, Galvão is investigating a sub-community of uterine pathogens that his group had previously identified in blood shortly after calving, which indicated that a hematogenous route of transmission was possible in cows — meaning uterine pathogens could be transferred to the uterus shortly after, or even before, calving.

“Meanwhile, our collaborator, Dr. K.C. Jeong, at UF’s Emerging Pathogens Institute and the department of animal sciences, has shown that that meconium, the earliest stool of calves, had a microbiome, and that an abundance of Bacteriodacae and Prevotellacea, two known families of uterine pathogens, in calves’ blood was positively correlated with the abundance of these bacteria in cows’ blood,” Galvão said. “These findings beg the question: If bacteria can colonize the amniotic fluid of the dam and the gastrointestinal tract of the fetus, and can be found in the fetal circulation, could it also colonize the uterus of the fetus? If the answer is yes, we would like to study possible routes of bacterial translocation from the dam to the fetal uterus.”

If the answer is no, Galvão’s team wants to know when in the life of a calf or heifer the uterus becomes colonized with bacteria. They also would like to determine the progression of the uterine microbiome from fetal life to the pregnant state.

“This knowledge would give us a better understanding of the uterine microbiota and uterine disease etiology and could completely change the way we approach uterine infection in cows, from prevention of uterine infection to prevention of uterine microbiome dysbiosis,” he said.

Galvão hopes the results obtained from both projects will ultimately lead to the development of better prevention strategies for uterine disease in cattle, which is expected to benefit the dairy industry and the public at large.