Productivity and Progesterone Profile of Nulliparous and Second-Parous Rabbits Characterized by Low and High Litter Size
This study aimed to evaluate the effect of the litter size (LS) category on the reproductive performance of nulliparous (NP) and second-parous (SP) NZW rabbits and the performance of their offspring. A total of 39 NP and 33 SP doe rabbits were divided into low (LLS, <7) and high (HLS, ≥7) after parturition. Reproductive measurements of each LS category and doe type were determined. The results show LS of 3-8 and 4-10 NP and SP, respectively. Doe rabbits with 6 LS show the highest distribution. Doe body weight at mating and from mating to parturition was higher (P<0.0001) for HLS than LLS, and SP than NP. Kit weight at birth and weaning, LS and viability were higher in HLS than in LLS does. At weaning, LS was higher (P<0.0001) in SP than NP. Levels of P4 at mid-pregnancy (P<0.001) were higher in HLS than in LLS, and in SP than in NP. In conclusion, a high litter size category (≥7/doe) was obtained from heavier NP or SP doe rabbits (LBW around 3 kg) and from second-parous compared with nulliparous does, with near similarity in conception rate of does. Weight and viability rate at birth and weaning as well as plasma progesterone level at mid-pregnancy were higher for does with high than low litter size category. In conclusion, body weight and parity may have a significant role in improving the litter size of doe rabbits, which may be useful in breeding and managerial programs to increase the economic value of rabbit production.
