Follicular,Oocyte and Embryo Features Related to Metabolic Status in Primiparous Lactating does Fed with High‐Fibre Rearing Diets

Fertility of primiparous lactating does in the early postpartum (pp) period is very low mainly due to pronounced deficient energy intake, influencing oocyte and embryo developmental competence. The hypothesis used in this work was that high‐lignin fibre diet supplied during the rearing period could increase feed intake and, consequently, improve the reproductive physiology and metabolic status of primiparous does in the early pp period. Diets with high‐lignin HL: 15.8% dry matter (DM)] or standard‐lignin content (SL: 4.9% DM) were supplied until parturition time. No diet effects in serum oestradiol, progesterone concentrations and follicle categories were found in the histological study. Metaphase II rate of in vitro‐matured oocytes was significantly higher in the SL vs the HL group (p < 0.001). Cytoplasmically degenerated oocytes (in terms of abnormal distribution of cortical granules) and follicular atresia rate were significantly lower in the SL group than in the HL group (p < 0.05 and p < 0.005 respectively). In addition, HL‐fed does showed lower number of viable embryos and higher rate of retarded in vivo‐recovered embryos compared with the SL group (p < 0.05). Neither in vitro embryo development of viable embryos nor conception rate was significantly different between groups. Feed intake increased during the first pregnancy in the HL group (p < 0.05), but not during early lactation. Serum protein, non‐esterified fatty acid and leptin concentrations, as well as estimated body composition were similar in does fed with both diets. In conclusion, the enhancement of reproductive management by using highly lignified products in rearing diets does not seem to report physiological reproductive benefits affecting oocyte maturation rate and embryo viability in primiparous lactating does.