Lambs born from ewes selected for calm temperament have higher rates of survival than lambs born from nervous ewes. The differences in survival rates may be because calm ewes produce better quality colostrum than nervous ewes. As the production of colostrum depends on hormonal factors, a possibility is that the differences reported in colostrum between the two lines is due to some differences in the hormones required for colostrum production. Therefore, we investigated whether temperament affects the hormones involved in the production of colostrum. Calm (n = 10) and nervous (n = 12) temperament ewes were housed indoor in individual pens. Blood was sampled (9 ml) by jugular vein venipuncture daily from 4 days before parturition and every 6 hours through to 24 hours after parturition. Plasma insulin, insulin-like growth factor 1 (IGF-I), prolactin and leptin levels were measured by radio immunoassay and analysed by a repeated measures ANOVA. Insulin concentrations increased directly after birth and were higher (F = 2.69, df = 7,137, p = 0.046) 2-8 hours after parturition in calm ewes (2 hr = 31.8 ± 9.9; 8 hr = 27.02 ± 9.5) than nervous ewes (2 hr = 17.9 ± 2.6; 8 hr = 9.5 ± 1.75). Calm ewes also tended (F = 2.2, df = 7,137, p= 0.079) to have higher concentrations of prolactin directly after parturition than the nervous ewes (Calm = 663.7 ± 69; Nervous = 528.5 ± 49.5). No differences were detected between temperament lines in the concentration of leptin or IGF-I at any time point. Both prolactin and insulin play a role in the production of colostrum, and our data suggests that the increased levels of insulin and prolactin in the calm ewes may contribute to the calm ewes producing better quality colostrum than the nervous ewes.