Vaughan Lee and John McGlone, Texas Tech University researchers, have been conducting an ongoing study focusing on increasing the reproductive output of gilts and sows.

The study is assessing the efficacy of treating female pigs with a specific growth factor to accelerate ovarian maturation and increase the number of developing follicles or ovulations. According to McGlone, the growth factor known as porcine EGF, is produced naturally in the pig and has been identified in many species.

Treatment of pig ovaries with EGF in culture resulted in an increase in two biochemical indicators of follicular development. These results indicate EGF has the potential to directly stimulate ovarian maturation.

The first studies involving live pigs used 18 gilts between the ages of 2-4 weeks in either control or EGF treatment groups. The gilts underwent minor surgery for placement of subcutaneous osmotic pumps. The pumps delivered a specific dose of EGF or a control solution over a 14-day period. During this time, both groups were individually housed. General health, feeding and behavioral observations were made and recorded.

Organ weights and tissue samples were obtained from both control and treatment groups at 70 days of age. Laboratory testing and data analysis from the early studies have been encouraging, McGlone reports.

EGF in live gilts caused a 70% increase in the number of activated follicles at 2.5 months of age, with no apparent adverse effects on health.

"In future studies, gilts will grow to maturity, and will be examined to determine whether puberty is accelerated and ovulation rate is increased," McGlone says.

Large-scale field testing will be undertaken at later stages of the project. Further development of the delivery system will enable easier and more effici ent treatment of large numbers of gilts in the commercial setting.

"Several diagnostic and therapeutic procedures aid the industry in increasing swine reproduction," McGlone relates. "However, stimulating early puberty and increasing ovulation rate have not yet been achieved by using modern biotechnology tools."

Researchers: Vaughan Lee, Department of Cell Biology and Biochemistry, Texas Tech University Health Science Center, and John McGlone, Professor of Animal Science and Director of the Pork Industry Institute, Texas Tech University. Phone McGlone at (806) 742-2826.