Effect of Dietary Energy Level on Milk Production in New Zealand White and Californian Does

Resumen

Objective: To evaluate milk yield in New Zealand White and Californian rabbit does fed high-energy diets.

Methodology: Milk production was measured in 72 New Zealand White and Californian does from kindling to 35 days postpartum. Four high-energy diets were formulated using the same ingredients, maintaining 17% crude protein (CP) and 14% crude fiber (CF), with progressively higher digestible energy (DE; kcal kg⁻¹) achieved by adding soybean oil. Milk yield was estimated under a controlled suckling scheme across six consecutive 7-day periods. A 2 × 4 factorial arrangement (breed × diet) was implemented in a completely randomized design. Data were analyzed using the MIXED procedure in SAS (v. 9.4). Wood’s lactation model was fitted to describe milk-production dynamics, estimate the day of peak yield, and assess lactation persistence.

Results: No differences in milk production were detected among treatments. The lactation curve showed an early peak (day 17) and moderate persistence (0.5). Average feed intake was similar across treatments, with no significant differences (p > 0.05).

Study limitations: The effects of high-energy diets were assessed in purebred animals; however, it would be pertinent to include both direct and reciprocal crosses in future studies.

Conclusions: Diets containing at least 17% crude protein and 2700 kcal DE·kg⁻¹ are recommended to sustain adequate milk production in New Zealand White and Californian rabbit does.