Figure 1From: Plasma Melatonin Levels in Relation to the Light-Dark Cycle and Parental Background in Domestic PigsDaytime (10:00–15:00; white horizontal bars) and nighttime (22:00–03:00; dark horizontal bars) plasma melatonin concentrations (mean ± sem) in piglets from different litters (n = 48, six piglets per litter, 3 males and 3 females). The mothers' melatonin levels are marked with open circles (A-D are sows and I-IV are gilts).Back to article page