INCREASING LITTER SIZE IN MID- OR OLDER-PARITY SOWS USING PROSTAGLANDEN F_(2 alpha) ON FARMS USING EARLY WEANING

摘要

Early weaning (EW) is common practice in the U.S. to improve herd health, overall productivity and farrowing facility utilization (1). However, a major concern of EW is that short lactation length is associated with small litter size as well as poorerreproductive performance. Specifically, increased numbers of pigs bom alive directly improve herd productivity (2). We have reported that subsequent litter size increases in parity >=3 sows as lactation length increases, while it does not increase in parity groups 1 and 2 (3). In sows, the endometrium regenerates until 18±3 days after farrowing. Additionally, high concentrations of progesterone in approximately 8% of weaned sows were reported (4).