In announcing a new research grant aimed at targeted antimicrobial use in dairy cattle, Texas Tech University said being able to maintain healthy animals and a sustainable agricultural product while also keeping antimicrobial use at a minimum is the goal for the agriculture industry, health officials and the general public.
Texas Tech assistant professor Vinicius Machado in the department of veterinary sciences is hoping to improve the judicious use of antimicrobial drugs in dairy cattle by predicting spontaneous cure and treatment failure of metritis, one of the more common diseases for which the drugs are used, the announcement said.
By identifying the novel predictors that indicate treatment outcomes, Machado said he hopes to develop selective treatment/management strategies that will keep antimicrobial drug use to a minimum in dairy cattle. His effort is being supported by a $464,338 grant over three years from the Cooperative State Research Education & Extension Service of the U.S. Department of Agriculture's National Institute of Food & Agriculture.
"Within the dairy industry, treatment of metritis is one of the major drivers of antimicrobial drug usage in lactating cows," Machado said. "However, antimicrobial therapy changes the outcomes of clinical cure in only 20% of metritis cases. Our objective is to identify cow-related factors that can be used to predict which metritis cases likely will benefit from antimicrobial therapy."
Machado is joined on the project by Michael Ballou, chairman of the Texas Tech department of veterinary sciences and an expert in ruminant nutrition and immunology, as well as researchers Klibs Galvao from the University of Florida, Fabio Lima from the University of Illinois and Noelle Noyes from the University of Minnesota.
Metritis is a painful postpartum uterine bacterial infection in dairy cows associated with decreased levels of milk production and fertility. It is one of the major drivers of antimicrobial drug use in lactating cows, most often the drug ceftiofur, a third-generation cephalosporin, the announcement said.
The World Health Organization considers ceftiofur to be a drug of highest priority to public health, and its use needs to be reduced when possible.
Plus, studies have shown that more than half of all metritis cases are cured on their own with no need for antimicrobial drugs, and cows show no sign of the disease two weeks after initial diagnosis, Texas Tech said. Ceftiofur treatment, however, has a failure rate of up to 26%, resulting in an approximately 20% difference in cure rate between treated and untreated cows.
Therefore, finding the cow-related factors that can be used to predict metritis cases that will benefit from antimicrobial drug use is crucial to determining which cows should receive antimicrobial therapy, the researchers said.
Machado feels that he will be able to identify the metabolic, inflammatory and immunological markers associated with metritis cases that likely will be cured with antimicrobial treatment and where treatment failure happens.
Machado said recent studies have shown that metritic cows treated with ceftiofur have better fertility than cows left untreated, but there was no difference in milk production between the two. So, the feasibility of any targeted treatment strategies developed from this study will depend on economics and drawbacks of antimicrobial resistance development associated with metritis therapy, he added, noting that data on resistance associated with metritis treatment with ceftiofur is scarce.
"Upon completion of this project, robust evidence on the potential economic benefits and antimicrobial resistance drawbacks due to ceftiofur treatment of metritis will be readily available to stakeholders and lawmakers," Machado said. "That will be instrumental to evidence-based decisions towards metritis treatment protocols and policies."