Relationship of estrone and prolactin with growth and survival of piglets to 35 d of age.

The relationship between estrogen or prolactin (Prl) status of pigs at birth and subsequent performance was examined in ten (Study 1) or seven (Study II) Yorkshire litters. In both studies, piglets were bled (3 ml) from the suborbital sinus at birth, and then hourly for 12 h. Hematocrit (Hct) and concentrations of plasma protein (PP) and estrone (E1) were determined on all samples. Concentrations of Prl were determined only in samples at birth. Weights at 3 and 5 wk of age as well as percent survival to 5 wk were obtained. Mean concentrations of E1 and Prl in piglets at birth were 6.97 +/- 44 ng/ml and 9.12 +/- .32 ng/ml, respectively. A decrease in E1 occurred over the first few hours after birth. Hematocrit values also decreased postnatally, whereas concentrations of PP increased. Sex of neonate did not affect any of the blood characteristics studied. Correlations between E1, PP, Hct and Prl at birth and body weights at birth, 3 and 5 wk were nonsignificant. However, piglets with higher Prl values at birth showed a greater survival rate. In Study II, half of the piglets in each litter were implanted at birth with silicone rubber implants containing estradiol-17 beta. Estrone concentrations were significantly higher in implanted piglets than in controls over the subsequent 12-h period, but Hct and PP values were not affected by treatment, suggesting that treated piglets did not consume more colostrum.(ABSTRACT TRUNCATED AT 250 WORDS)