Today's swine producers strive to keep production costs in check while optimizing productivity and product quality to meet demand in the marketplace. To do this, some producers are investing in assisted reproductive technology-artificial insemination, embryo transfer or cloning - to improve the genetics of their herds, according to Dr. C. Edward Ferguson, associate professor of animal sciences and one of the researchers at McNeese.
"Pigs usually produce a large number of offspring, which in turn brings in more money, so the management of reproduction on a pig farm is important," he said. "With the tremendous rise in the cost of feed inputs for sows, producers can't afford for a sow not to carry a pregnancy to full-term," said Ferguson.
"In the sow, corpora lutea must be present the entire length of gestation (114 days) in order for pregnancy to result in physically healthy piglets," explained Ferguson. CL is formed from the multiple follicles that ovulate during the estrus cycle of pigs and the chief product is progesterone, a hormone involved in pregnancy that supports gestation.
"A total of four CL are required during pregnancy or the pregnancy will result in abortion and there are instances including commonly used management practices that can result in the removal of CL during pregnancy. We wanted to see if a protocol to 'save' the pregnancy could be created for these situations and result in the birth of live healthy piglets."
Two experiments were conducted on 22 mature sows at the McNeese farm. The first was to determine if Altrenogest, an orally administered progesterone, could support pregnancy in the absence of functional CL, while the second experiment tried to determine if new CL could be induced in pregnant sows administered PGF2α, a drug that causes CL regression.
"We administered Altrenogest and were able to maintain the pregnancy in the absence of CL and then superovulated the sows while pregnant to induce the formation of new CL that would maintain the pregnancy to full-term," said Ferguson.
From the second experiment no piglets were born, but the team was successful in maintaining pregnancies on induced new CL. These new CL maintained pregnancy for an average of 20 days following the removal of Altrenogest in three sows with successfully induced CL," said Ferguson.
"This is important," he said, "because even though you can maintain pregnancy in a sow on progesterone she will not farrow (give birth) normally without CL."
The research - published in the peer-reviewed Trends in Animal and Veterinary Sciences Journal - should be the first report in the scientific literature of maintaining pregnancy on Altrenogest and continuing pregnancy from as early as day 30 of gestation in a pig without CL, according to Ferguson. "We are optimistic about our research and plan to continue our work in this area."
The department will also continue to include undergraduate and graduate students in its research projects to give them hands-on experience, according to Dr. Chip LeMieux, department head and researcher on this project.
"One of our students who worked with us on this project was Devin Gandy, who earned both his bachelor's and master's degrees at McNeese," said LeMieux. "He was so excited about the opportunity he had as a junior to conduct cutting-edge research through our undergraduate research program that he decided to pursue his graduate degree. Gandy is now a swine research coordinator at the U.S. Meat Animal Research Center in Clay Center, Neb."
This research is intriguing, explained LeMieux, "The swine industry is progressive in implementing new technology. Currently, over 98 percent of all the sows are bred using artificial insemination. If we are able to refine the techniques of our research it may be an applicable procedure for the industry."
Ferguson sees the future potential of this discovery in human reproductive medicine. "Our research could serve as a model for medical physicians to induce additional CL in women who experience early miscarriages. By increasing progesterone in these pregnant women in a more 'natural' way-that is allow their body to produce the progesterone instead of administering a synthetic progesterone - this procedure if proven effective could reduce infertility or early miscarriages due to luteal dysfunction in women."