Burns’ research seeks to solve challenges with cattle pregnancy lossWritten by Saige Albert
Patrick Burns began researching cattle pregnancy loss in graduate school at Clemson University and his post-doctorate program at the University of Kentucky. Since the late 90s, Burns’ research has explored factors in pregnancy loss, and his current project looks at maintaining pregnancy in cattle.
“The goal of this project is to manipulate a hormone called prostaglandin F2alpha,” Burns, who is now an associate professor at the University of Northern Colorado, explains. “The hormone normally regulates heat cycles. We are trying to regulate the hormone in pregnant animals as a way to reduce embryo loss.”
Burns, along with graduate students Peter Graham and Michele Plewes, is pursuing a project to attempt to reduce early pregnancy loss by blocking the release of prostaglandin F2alpha.
Prostaglandin F2alpha is normally released in the non-pregnant cow late in the heat cycle. The hormone stimulates the death of the corpus luteum, which is the ovarian structure that supports pregnancy.
“My current research focuses on prostaglandin metabolism in reproductive tissues of mammals,” Burns comments. “Specifically, I am investigating the use of long-chain omega-3 fatty acids as a way to reduce prostaglandin secretion in uterine and luteal tissues and improve reproductive efficiency.”
“Early pregnancy losses cost the U.S. dairy and beef industries millions of dollars annually in lost meat and milk production,” Burns comments. “It has been estimated that 20 to 30 percent of all pregnancies are terminated within the first 30 to 60 days, and there are a number of factors that can lead to early pregnancy loss.”
He cites failure in fertilization, chromosomal abnormalities and failure in maternal recognition of pregnancy as top causes in pregnancy loss.
“Maternal recognition of pregnancy is the period of time where the embryo must signal the cow to let her know she is pregnant,” he explains. “This signal occurs between days 13 and 21 after mating.”
Burns notes that during that time, the embryo blocks the release of prostaglandin F2alpha, which prevents the loss of the corpus luteum so the pregnancy can be established.
“In these early pregnancy losses, a viable pregnancy or a viable embryo may have a weak signal or a signal that is a little late, so prostaglandin is released, and it regresses the corpus luteum,” Burns says. “The pregnancy is lost.”
Burns’ research with fish oils aims to alter prostaglandin release in early pregnant cow to improve pregnancy loss.
“Omega-3 fatty acids may regulate prostaglandin F2alpha during early pregnancy and assist the embryo with maternal recognition of pregnancy,” he adds. “What we are trying to do is manipulate prostaglandins.”
Phase one of Burns’ research invested the use of omega-3 fatty acids to regulate lipid microdomain distribution and prostaglandin F2alpha receptor movement in the plasma membrane of luteal cells and was recently completed. He notes that they have purchased cattle for phase two of the project.
“Phase one was all lab work,” he says. “In phase two, we are going to give low doses of a commercial prostaglandin – Lutalyse®, to regulate corpus luteum function.”
Burns cites work by Milo Wilkbank at the University of Wisconsin who demonstrated that four low doses of prostaglandin resulted in death of the corpus luteum, and only two doses of prostaglandin, alternating with saline, resulted in loss of about half of the corpora lutea.
“We hope we can use omega-3 fatty acids to decrease the percentage of corpora lutea that regress with low doses of prostaglandin F2alpha,” he adds.
As part of phase two, Burns also noted that they will biopsy the corpus luteum and look at changes in the genes that regulate the corpus luteum.
“This project runs until 2017, but we are hoping to wrap up the studies in the next year,” Burns said.
“Ultimately, we want to start taking some of the information we have learned to the field, and I’m hoping to be able to do some breeding projects in the next year or two,” he added.
Burns hypothesizes that supplementing cattle diets with fishmeal or fish oils, which are high in omega-3 fatty acids, could allow producers to regulate prostaglandin F2alpha secretion in breeding cows.
“We believe that omega-3 fatty acids may reduce prostaglandin F2alpha or lead to production of prostaglandins with less potency in reproductive tissues,” he says. “This, in turn, may help embryos that have difficulty in regulating prostaglandin F2alpha and prevent loss of pregnancies.”
Burns notes that it may be possible to deliver fishmeal in a protein supplement or fish oil in a lick tub to range cows, and he further adds that Dan Rule of the University of Wyoming has also looked at use of omega-3 fatty acids in cattle diets, as well.
Retention of pregnancy, especially at this point in the cattle market, is very important, Burns notes, adding that even one more pregnancy means a significant amount of money.
“We’ve done some preliminary studies, and right now, we generally have about 10 to 15 percent improvement of pregnancies,” he says. “That means a lot right now.”
University of Northern Colorado Associate Professor and researcher Patrick Burns notes that some researchers have hypothesized that microdomains, or regions within the plasma membrane of cells, may play a role in cell signaling.
“These microdomains may act as platform for the on-off switches during cell signaling,” he says. “They probably bring a hormone receptor in contact with its downstream signaling molecules.”
“We think we may be disrupting those domains with fish oil to decrease the signals,” Burns says. “Recent studies conducted in our laboratory show that omega-3 fatty acids in fish meal became incorporated into cellular membranes within the corpus luteum and reduced prostaglandin F2alpha signaling and expression of genes that regulate the lifespan of the corpus luteum and progesterone synthesis.”
Burns notes that their laboratory is utilizing a technique called single particle tracking to measure the movement of individual receptors on the plasma membrane.
“We suspect that omega-3 fatty acids will disrupt microdomains and prevents the receptor from interacting with protein on switches, leading to reduced prostaglandin F2alpha signaling,” he said.