Abstract #5

# 5
Future reproduction in gilts and boars is affected prenatally by sow management and early in life by management conditions to which the developing swine are exposed.
Mark J. Estienne*1, 1Virginia Tech, Blacksburg, VA.

Applied research at Virginia Tech has focused on effects of pre- or post-natal conditions on reproduction in adults. In utero, swine fetuses can be programmed as a consequence of intrauterine growth retardation (IUGR) caused by insufficient uterine capacity. Although negative effects of IUGR on postnatal growth are well documented, possible reproductive effects have been less studied. Preliminary work from our laboratory, however, showed that low BW boars had poorer libido and semen quality than high BW boars; in gilts, age at puberty was negatively correlated with pig BW. It is becoming apparent that fetuses can also be programmed by management of the gestating sow. For example, we compared growth and reproductive characteristics of gilts farrowed by sows that were kept in individual crates throughout gestation, group pens throughout gestation, or individual crates for the first 30 d post-mating and then group pens for the remainder of pregnancy. During the last 4 wk of the grow-finish period, BW of gilts farrowed by females housed in crates throughout gestation was greater than BW of gilts in the other 2 groups. Also, the efficiency of feed conversion was greatest and last-rib backfat thickness the least, in gilts farrowed by females housed in crates throughout gestation. Interestingly, fewer gilts farrowed by females kept in crates throughout gestation reached puberty by 165 d of age compared with the other 2 groups. In intensively managed swine operations, there are many potential environmental stressors to which postnatal pigs are exposed early in life and this may affect future reproduction as well. For example, we determined the effects of crowding in the nursery on future reproduction and longevity in gilts. Reproductive performance during the second parity, including the number of pigs born alive was significantly greater for gilts each allowed 0.25 m2 of floor space in the nursery compared with gilts restricted to 0.17 m2. Research will continue to identify prenatal or early-in-life stressors and to develop management strategies for mitigating adverse effects on swine reproduction.

Key Words: gilts, boars, development

Speaker Bio
Mark J. Estienne was born and raised in southeast Virginia.  He received his B.S. (1982) and M.S. (1984) degrees in Animal Science from Virginia Tech and earned a Ph.D. degree (1987) from the University of Georgia.  After postdoctoral training at the University of Kentucky, he joined the faculty at the University of Maryland Eastern Shore as an assistant professor with a teaching, research, and Extension appointment.  He was promoted to associate professor in 1996 and in 1999 moved to the Virginia Tech- Tidewater Agricultural Research and Extension Center in Suffolk, where he is currently a Professor and Swine Research Physiologist.  He has a research and Extension appointment.  His research interests are in the areas of sow and replacement gilt management and enhancing semen quality and libido in boars.