SUMMARY & CONCLUSION

1. Fetus (~ 30 days of gestation) Regressing uterine fluid Abstract # 26648 MAINTENANCE OF PREGNANCY WITH MATRIX IN PGF2α-TREATED SOWSC.E. Ferguson, M.C. Poole, D.M. Gandy, F.M. LeMieuxDepartment of Agriculture, McNeese State University, Lake Charles, LA OBJECTIVES The objective of this experiment was to determine if pregnancy could be maintained in sows using Matrix as a progestin in sows induced to undergo luteolysis during pregnancy. MATERIALS & METHODS A total of nine crossbred (Yorkshire x Landrace) sows were utilized for this experiment. Over a period of four months these sows were naturally mated with a boar (Hampshire) of proven fertility. At approximately 30 days post-mating these sows were ultrasounded to determine whether a pregnancy was established from the mating. Once the sows were determined pregnant they were randomly allotted to one of two treatment groups. The control group consisted of receiving two 15 mg doses of PGF2αat 12 hour intervals and no further treatment. The sows allotted to the treatment group received two 15 mg doses of PGF2α at 12 hour intervals and then received 30 mg of the Matrix daily beginning immediately after PGF2α administration. The Matrix was administered via top-dressing bread and was continued for sows in treatment group for 7 days. During the treatment period, all sows were ultrasounded daily to observe pregnancy status until abortion was completed. RESULTS CONTINUED The control sows returned to estrus following completion of the abortion process. The Matrix treated sows remained pregnant, as determined by the presence of viable fetuses and increasing uterine fluid during the treatment period. Following the cessation of Matrix supplementation, treated-sows began the abortion process in 2 to 3 days and completed the abortion process 4 to 5 days later. INTRODUCTION In the sow, corpora lutea are required for the entirety of gestation for pregnancy to be maintained and the removal of the corpora lutea at anytime during gestation will result in abortion. Previous studies have demonstrated that pregnancy can be maintained in luteoectomized sows with daily progesterone injections, however it is desirable to be capable of maintaining pregnancy in a luteoecomtized sow without daily progesterone injections. The need to maintain pregnancy in a sow induced to undergo luteolysis while pregnant exists due to a method of estrus synchronization in the sow. This method of estrus synchronization in the sow is the administration of PGF2α to approximately 30-day pregnant sows to induce abortion and subsequently estrus. The utilization of this protocol allows for the opportunity for a pregnant sow to be misidentified and inadvertently administered PGF2α. In this situation, a producer may want to “rescue” the pregnancy should the expected litter be genetically valuable. This research was conducted to determine if pregnancy in the sow could be maintained on Matrix (orally active progestin) which can be administered daily by top-dressing the ration instead of having to administer daily injections of progesterone. Table 1. Time in days until initiation of abortion process to completion of abortion process following PGF2α administration. SUMMARY & CONCLUSION The control sows began abortions approximately 72 hours post-PGF2α which is consistent with the reported literature. The fact that 7 days of Matrix supplementation postponed the initiation of the abortion demonstrates the ability of Matrix to maintain pregnancy in sows at least 30 to 45 days of gestation, when supplemented at a rate of 30 mg per head per day. The advantage of using Matrix is the ease of administration (top-dressing feed with medication) compared to other methods of supporting pregnancy that require daily injections. The next step in this experiment will be to continue the support of pregnancy with Matrix and further reducing the dosage to determine the minimum required dose to support pregnancy in the sow in the absence of luteal tissue. Figure 2. Ultrasound images of pregnancy and abortion in experimental sows. RESULTS As expected, the control sows began the abortion process, as determined via ultrasonography (the reduction in uterine fluid and regression of fetal tissue), between 2 and 3 days following initial PGF2α administration. The abortion process was completed (complete absence of fetal tissue and reduction of most uterine fluid) in the control sows by day 4. Figure 1. Time table depicting duration of treatment for experimental and control-treated sows.