MATERNAL-BEHAVIOR IN NEW-ZEALAND WHITE-RABBITS - QUANTIFICATION OF SOMATIC EVENTS, MOTOR PATTERNS, AND STEROID PLASMA-LEVELS

Several parameters associated with maternal behavior were quantified u nder laboratory conditions in New Zealand white rabbits. Digging behav ior appeared earliest (8-6 days prepartum), its decline preceding the onset of straw carrying (3-1 days prepartum). Hair pulling consummated the construction of the maternal nest. Food intake significantly decr eased on days 2 and 1 prepartum. On parturition day, all females spent 300-500 s with the litter while, for the rest of lactation, nursing b outs lasted 199 +/- 7 s. Milk yield increased linearly up to lactation day 19, declining thereafter. Pup weight increased linearly throughou t lactation despite the decline in milk yield. Plasma estradiol (E) le vels did not significantly vary across pregnancy: 60 +/- 2 pg/ml (days 10-25) and 75 +/- 6 pg/ml (day 30). The testosterone (T) levels at th ese times were: 200 +/- 10 and 308 +/- 0.03 pg/ml, respectively. Testo sterone significantly declined from pregnancy day 30 to lactation day 1 (202 +/- 0.02 pg/ml). Progesterone (P) levels significantly declined from pregnancy day 20 (9 +/- 1 ng/ml) onwards. Progesterone levels we re negligible across lactation. Thus, mother rabbits display a sequenc e of motor patterns and somatic events correlated with changes in plas ma levels of T and P against a background of E.