Researcher conceives new cow pregnancy test

Thomas "Tod" Hansen recently won the Animal Physiology and Endocrinology Award from the American Society of Animal Science. As a young man working on his family ranch, Colorado State University reproductive scientist Thomas “Tod” Hansen checked cattle for pregnancy using conventional rectal palpation – a routine and inexpensive method that can be stressful for cows and physically demanding for technicians. There’s got to be a better way, he thought. Hansen, now director of the highly regarded CSU Animal Reproduction and Biotechnology Laboratory, has become a leading scientist working to understand the dynamics of livestock pregnancies at the molecular level. He also is leading new discoveries in the economically devastating bovine viral diarrhea virus (BVDV), in part because of links between cattle pregnancy and viral infection. A national honor For these and other achievements, the American Society of Animal Science recently conferred to Hansen its Animal Physiology and Endocrinology Award for important research contributions to the livestock industry. “Dr. Hansen has emerged as the leader in maternal recognition of pregnancy in ruminants,” CSU Distinguished Professor Emeritus George Seidel, an eminent reproductive scientist, wrote in an award-nomination letter. “His seminal discoveries have advanced our basic understanding of the mechanisms involved in embryo recognition by the mother, and also have provided new diagnostic tools to identify problems that limit reproductive efficiency.” [caption id="attachment_3780" align="alignright" width="300"]photo of cows Hansen is developing a blood test to detect pregnancy in cattle as early as 16 days after breeding.[/caption] Hansen’s discoveries have led to several patents, critical steps in innovation and the introduction of new technologies to the marketplace. In this case, the patents were issued for blood markers that Hansen is using to develop pregnancy and viral screenings that would represent significant progress in managing livestock health. “Our goal is to find the non-virally infected and non-pregnant animals in order to better manage reproduction and animal health,” Hansen explained. Early detection crucial He is developing a blood test to detect pregnancy in cattle as early as 16 days after breeding, compared to at least 25 days with ultrasound and some 35 days with rectal palpation. Such a test would detect pregnancy – or, more importantly, non-pregnancy – earlier than others on the market. The time savings means a cow that is not pregnant could be quickly rebred so she remains productive and on pace with the rest of the herd, particularly important for purebred cattle operations and advanced dairies with thousands of milking cows. Considering there are more than 9 million dairy cows in the United States, the savings to producers would mount quickly. Hansen also is investigating use of markers in new serum screenings that would identify cows and cattle fetuses infected with BVDV. The research is important in the context of reproduction because BVDV is transmitted from cow to unborn calf, resulting in aborted and stillborn calves, calves that die young, and calves that live but spread the virus to entire herds; the latter group, known as persistently infected, is the main source of BVDV infection in cattle. [caption id="attachment_3809" align="alignright" width="300"]photo of Tod Hansen Hansen studies livestock pregnancy and viral dynamics at a molecular level.[/caption] Such knowledge is important because BVDV is difficult to control: Vaccination programs are not universally implemented or 100 percent effective, and the virus spreads easily through the mouth or respiratory tract. Much of Hansen’s work centers on interferon, a protein that signals pregnancy to a cow’s body and helps retain an embryo. He found that interferon triggers the creation of another protein, known as ISG15, a marker that could be central to identifying both pregnancy and viral infection. “Subsequent research has demonstrated that ISG15 has important roles during pregnancy in all mammals studied to date, ranging from mice to humans,” Seidel wrote in his nomination letter, suggesting the far-reaching implications of Hansen’s discoveries. CSU influences A professor in the CSU Department of Biomedical Sciences, Hansen came to science through hands-on work on his family cattle ranch near Fort Collins. During calving season, he often referred to a CSU book titled, “Artificial Insemination and Reproductive Management of Cattle,” co-authored by Seidel, a member of the prestigious National Academy of Sciences and a pioneer in cattle reproduction. “This book was like a bible to me,” Hansen recalled, reaching to an office shelf to retrieve his original, tattered copy. He also was intrigued by embryo transfer and cryopreservation of gametes – advances brought to the family ranch by Hansen’s father, an obstetrician-gynecologist naturally interested in advances in reproductive science. Seidel, who helped determine how to sort cattle sperm by gender, reflected on his colleague’s scientific honor. “Tod has remarkable scientific expertise and success, as well as integrity and willingness to help others,” said Seidel, who is retired but still active at the CSU Animal Reproduction and Biotechnology Laboratory. “The award is for the science. The other is icing on the cake.”

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Researchers examine disease in mountain lions

A Colorado State University research team is examining how illnesses are transmitted in mountain lion populations in an effort to manage future outbreaks of diseases, such as feline leukemia virus, that could threaten the species.

Susan VandeWoude, a research veterinarian and associate dean for research in the CSU College of Veterinary Medicine and Biomedical Sciences, is leading a team that recently received $2 million from the National Science Foundation for a five-year study of the big cats.

The project is expected to shed light on the complex outcomes of human impact – both wildlife-management practices and land development – for a particularly sensitive species of wild cats in the United States. These interwoven consequences, which the scientists have identified through earlier research, include changes in puma populations, population movement and disease dynamics that could have implications for pumas and other cat species, including housecats.

Disease paths

The new research is designed to further understand how people affect puma movements in the wild and the way that disease travels through populations, providing insight about wildlife management used from Florida to California.

For example, when an endangered subspecies called the Florida panther was nearing extinction in the Everglades in the mid-1990s, wildlife managers imported Texas cougars to breed with their cousins. Managers hoped to rebuild the population. For the most part, it worked: Officials estimated last year that this cat population is about five times larger than it was two decades ago.

Other states have used different tactics to deal with the species referred to interchangeably as pumas, cougars or mountain lions. California has banned the hunting of pumas for decades. Hunters on Colorado’s Western Slope are asked to avoid killing female lions in places with low population.

Multidisciplinary effort

Joining VandeWoude in the interdisciplinary research at CSU are Kevin Crooks, a professor in the Warner College of Natural Resources, and Chris Funk, an associate professor in the College of Natural Sciences.

Each researcher brings distinctive expertise to the project: VandeWoude is an authority on feline diseases; her discoveries include uncovering a new family of feline herpesviruses that infects housecats, pumas and bobcats. Crooks, a wildlife ecologist, specializes in the effects of manmade disturbances on the natural world, so he is focusing on how puma habitat and travel corridors have been affected by urban and housing development.

“Large carnivores like pumas tend to be especially sensitive to human impacts,” Crooks said. “They’re often the first to feel the effects, like a canary in the coal mine.”

Funk will use cutting-edge techniques to compare the genetics of various puma populations so that scientists may assess the degree to which they have interbred – providing evidence about their travel patterns.

“It’s hard to track how they move, so we use genetics to infer where they’ve gone,” Funk said. “If you have two groups with similar genes, you can infer that they have interacted.”

Other researchers

Two faculty members from other institutions, Meggan Craft of the University of Minnesota and Scott Carver of the University of Tasmania, will perform the mathematical and statistical analyses needed to create models of how disease is expected to spread geographically through puma populations.

Other collaborators include Dr. Holly Ernest and colleagues from University of California, Davis, and a large number of wildlife managers, field biologists and veterinarians working for state and federal agencies.

The team will examine how wildlife management approaches influence disease transmission. In the case of the Florida panther, for instance, did the imported Texas cougars bring pathogens with them that affected the panthers?

“We’re studying the effects of that intervention, and the intersection of that with landscape dynamics,” VandeWoude said, citing rivers, highways and cities as possible barriers to puma movement and factors in disease transmission.

She explained that researchers can track the speed and direction of virus movement by testing various puma populations and comparing results. For example, the team will try to predict what pathways diseases like the feline leukemia virus will take when spreading through a population, and which groups of pumas are particularly susceptible to outbreaks. The models the team generates will also inform predictions about how disease could spread to pets and humans.

Video game on tap

As an outreach project, one of Crooks’ former postdoctoral students will create a video game that simulates disease movements and lets players manipulate puma populations to help them avoid infection.

The new study is a continuation of a project that VandeWoude and Crooks recently completed on disease transfer within three cat species, in which they compiled a database of puma blood samples and pathogens.

“We now have data on a high percentage of the puma population in our study areas, partly because they are so limited in number,” VandeWoude said.

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