The effects of dietary energy level and added fat were studied by comparative slaughter on 60 primiparous rabbit does in different reproductive states. Nine does were slaughtered immediately after their first parturition (preliminary slaughter group) to estimate initial empty body composition. The 51 remaining does were divided into three groups and given diets differing in digestible energy (DE) content: M (11·28 MJ/kg dry matter (DM); H (12·16 MJ/kg DM); F (11·93 MJ/kg DM, obtained by the inclusion of 25 g/kg of animal fat). Thirty-six does (12 per group) were remated 3 to 4 days after parturition, after which 20 does were concurrently pregnant and lactating (LP) and gave birth a second time. At the second parturition these does were slaughtered with their new-born litters. The non-mated or non-pregnant lactating does (LN) were slaughtered at the same time. All litters from the first parturition were weaned at the 30th day of age.
The diets influenced the DE intake (3·11 v. 3·31 and 3·36 MJ/day, P < 0·05) and the milk production (171 v. 180 v. 191 glday, P < 0·05), respectively for the M, H and F diets. The high-energy diets (H and F) significantly modified the final empty body composition. The loss of body fat was proportionately 0·34, 0·36 and 0·39 of the initial body fat and the loss of energy was proportionately 0·17, 0·19 and 0·21 of the initial body energy in the M, H and F groups respectively (P > 0·05) (average of LP and LN does). The maternal diet significantly influenced the weight of the sucking litters (first parturition) at 20 days (2409 and 2454 v. 2629 g, P < 0·05).
The LP does showed lower DE intake, milk yield (from 10 to 30 days) and litter weaning weights than LN does. Between the first and the second parturition, the LP does had a loss of empty body weight and a negative protein balance (-0·06 of the initial content), while the LN does had an increase in live weight and empty body weight and a positive protein balance (+0·11 of the initial content). Both LP and LN does had a negative energy balance (−0·24 v. −0·25, respectively; P < 0·01).