Landrace × Large White gilts and sows (parities 2 and 3 at mating) were uninjected (controls) or injected daily with porcine ST (pST; gilts: 2.5 mg/d; sows: 4.0 mg/d, each approximately 15 µg of pST/kg per day) from d 25 to 50 of pregnancy (short-term pST) or from d 25 to 100 of pregnancy (long-term pST). Fostering was performed on the day of birth to achieve litter sizes at the beginning of lactation of 10 piglets (where possible) in first-lactation sows and 12 piglets in older lactating sows. Dam removals and removal reasons were recorded throughout the trial, from alloca- tion at d 25 of pregnancy until weaning of the litter after the treatment pregnancy. 2Chi-square analysis. 3In sows, dam removals during pregnancy did not differ between treatments (P = 0.448). In gilts, removal rates did differ between treatments (P = 0.024) such that 12% of gilts treated with pST from d 25 to 100 of pregnancy were removed before entry into the farrowing house compared with a 5% removal rate in controls (P = 0.062). 4Dams in replicates 11 and 12 of the study were not followed through lactation because a subset of their progeny were removed at birth for muscle fiber analysis.