By earning a National Science Foundation fellowship that was awarded to barely 10 percent of the 17,000 applicants, Department of Dairy Science and Endocrine and Reproductive Physiology Ph.D. student Samantha Weaver has definitely shown she’s not just another part of the herd.
Weaver received the graduate fellowship to pursue research on the mammary gland in dairy cows. Specifically, she looks at how cows pull calcium from their bones to put into the milk they produce. She’s investigating the complex chemical mechanisms that allow this process to happen inside a cow’s body.
“Lactation is an interesting time because everything related to how the body usually functions gets overhauled,” Weaver says. “The grant focuses on understanding this mechanism in the dairy cow because it’s never been described before. It’s understanding the mammary gland at the DNA level.”
She explains that for a long time it was thought that parathyroid hormone causes the extraction of calcium from a cow’s bones during lactation. However, she’s found evidence that this is regulated by the role of serotonin in stimulating production of parathyroid hormone-related protein, which is similar to parathyroid hormone but acts differently. This phenomenon may be what truly makes this process possible.
While the difference is subtle, Weaver says knowing the molecules that make up this pathway is the key to alleviating the many problems caused my hypocalcemia, which occurs when cows pull so much calcium out of their bones for their milk that there isn’t enough left for other important bodily functions, such as muscle contraction. The result can be loss of productivity and poor overall cow comfort.
“What I like about this work is that it can have very clinical endpoints,” Weaver adds. “The negative effects of hypocalcemia costs the dairy industry millions of dollars each year, so if by understanding this process we can come up with a type of treatment it would be very beneficial. Hypocalcemia is especially a problem because it’s often an issue in a large number of cows but goes undetected because they don’t show outward signs of illness, called the subclinical stage.”
Her research also has implications on another species that has mammary glands and utilizes many of the same pathways for lactation — humans. While there are some differences, dairy cows are much more similar to humans than mice, the animal most commonly studied in the lab, so Weaver hopes her research can lead to insights about women’s health as well.
“I like the translatability of this research and how I’m able to really make my research relevant to human health as well, illuminating how it works in both species,” she says. “It totally blows my mind that you can understand what’s going on at a molecular level and it has enormous ramifications on the overall health of the species.”
Weaver’s path to getting involved in research on dairy cows is anything but ordinary. A Spanish major in her undergrad at UW-Madison, Weaver was taking science classes with plans to possibly attend medical school. Her sophomore year she got involved in the lab of assistant professor Laura Hernandez in the Department of Dairy Science. From there she was hooked and started a Ph.D. in the lab right after graduation.
While her focus is on a molecular approach to dairy science, Weaver enjoys how diverse her department is, studying all aspects of dairy to further the industry. Since starting her Ph.D. she’s become involved in Badger Dairy Club and helped out at the World Dairy Expo. She was also awarded the Hoard’s Dairyman graduate student award last year.
“Dr. Hernandez took a chance on me and it really worked out well for the both of us,” says Weaver, who is bilingual in Spanish and volunteers regularly at medical clinics around Madison that focus on Spanish speaking populations. “This grant is huge for me because of what it demonstrates. I want to go into research and academia and to be successful you need to have funding. This establishes at a very early point in my career that I can do this.”