Effects of brief maternal separation in kids on neurohumoral and electroencephalographic parameters

In goat a selective and reciprocal mother–young bond is rapidly established at birth and persists even beyond the lactation period under natural conditions. Therefore physical separation of mother and young may result in psychobiological disturbance. Aim of this study was to assess quantitative electroencephalography (q-EEG) and neurohormonal markers accompanied by behavioural observations (vocal rate) before and after separation in growing kids. Seven healthy Saanen kids showing normal behavioural patterns were selected just after 2 days from birth. Kids were tested before (basal condition: B) and after separation (separation condition: S) from their mother, respectively at 15 (T1), 30 (T2), 45 (T3), 60 (T4), and 75 (T5) days of age. For each experimental session tests were sequenced, basal test followed by separation test. All experimental trials were videotaped and analysed. Each EEG recording session lasted 10 min. At the end a standardized method for blood collection was implemented. Blood samples were collected in order to perform cortisol serum and catecholamine (epinephrine, norepinephrine, dopamine) plasma levels by radioimmunoassays. q-EEG analysis was performed using Fast Fourier Transform (FFT); the spectral bands delta (0.5– 4.0 Hz), theta (4.1–8.0 Hz), alpha (8.1–12.0 Hz), and beta (12.1–30.0 Hz) were calculated and expressed as relative power (%). Kolmogorov–Smirnov test for normality and paired t-test were used for statistical comparison. Statistical analysis showed significant increases in cortisol, epinephrine, norepinephrine levels, and significant decrease in dopamine levels between BT1 versus ST1. Significant increase was found for theta band between BT2 versus ST2, whereas a significant decrease was found for alpha band between BT5 versus ST5. Kids tended to vocalize more in S, but this difference was significant only between BT1 versus ST1 and BT2 versus ST2 (Wilcoxon’s test). These results, as well as behavioural data, suggest a main response of both sympatho–adrenal axis and adrenal cortex and a bioelectrical activity response to maternal separation.