Prenatal stress, the stress imposed on a pregnant dam that may influence her subsequent offspring, has been shown to have profound effects on behavior and physiology of many species, including swine (Haussmann et al., 2000; Tuchscherer et al., 2002; Kanitz et al., 2003; Otten et al., 2004). Research in our laboratory (Haussmann et al., 2000) has shown that prenatal stress, including restraint and ACTH injection of the sow, caused offspring to have altered neurohormones and adrenal gland morphology, greater plasma cortisol in response to stress, and less ability to heal a wound. Similarly, another research team has recently published a series of papers (Tuchscherer et al., 2002; Kanitz et al., 2003; Otten et al., 2004) in which they used either 5-min restraint stress or exogenous ACTH administration during sow gestation to cause prenatal stress. Those researchers found that prenatal stress impaired the immune function, increased the maximum binding capacity of glucocorticoids receptors in the central nervous system immediately after birth, and caused an increase in fetal cortisol that may be the mechanism by which prenatal stress causes its effects. Kranendonk et al. (2005) recently reported that oral administration of glucocorticoids to pregnant sows might prove to be a useful model for studying its deleterious effects. The phenomenon of prenatal stress demands our complete understanding to optimize both welfare and productivity in farm animals because prenatal stress can affect both the physiology and behavior of animals and it affects a wide array of species. Thus, to further explore the phenomenon of prenatal stress and its effects in swine, we subjected gestating sows to i.v. injections of ACTH (1 IU/kg of BW), exposure to rough handling for 10 min (Rough), or no treatment (Control) once a week during d 42 to 77 of gestation. To determine the plasma cortisol response to treatments, blood (5 mL) was collected from 30 sows after treatment administration. To conduct the prenatal stress study, a separate group of 56 sows was used in 1 of 4 replicates. At birth, production data were collected for each litter, including birth weight, number born, anogenital distance, and pig viability. At weaning, pigs were blocked by BW and sex, and placed in a nursery pen of 6 pigs, with 2 pigs from each treatment group. To assess the effect of treatments on cortisol, corticosteroid- binding globulin (CBG), and hematological cell profiles, blood was collected every other day for 10 d after weaning. Application of treatments caused plasma cortisol concentrations to be greatest in ACTH sows compared with Control sows (P < 0.001), with Rough sows having intermediate values (P = 0.07). Treatments did not affect the number of pigs born, number of stillborn, or pig viability (P > 0.40). The ratio of cortisol to CBG did not differ between treatments (P = 0.09). Hematological variables did not differ between treatments (P > 0.19). Pigs born to ACTH sows had a smaller anogenital distance compared with controls (P < 0.03), with pigs from Rough sows being intermediate. Our data indicate that swine exposed to prenatal stress (ACTH injection) can have alterations in sexual morphology without effects on growth or the immune cell populations measured in this study.

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