Maria Laura Marongiu

Effect of pre-weaning solid feed and milk intake on caecal content characteristics and performance of rabbits around weaning

Abstract The aim of this study is to know the effect of different solid feed and milk intake during suckling on performance around weaning and on caecal content characteristics at weaning. In order to obtain different intakes of milk and solid feed, 13 litters of pregnant females (PF) inseminated the day after delivery and 14 litters of non-pregnant females (NPF) were compared. At birth the litters were equalized at eight pups and during lactation dead pups were replaced by pups of the same age from nursing does. Compared to the PF group, rabbits in the NPF group had a higher milk intake (26.0 versus 21.4 g/day; P < 0.01) and lower solid feed intake (9.1 versus 11.5 g/day; P < 0.01) between 20 and 28 days of age. No significant difference was observed between the two groups in weight gain before and post-weaning (28-49 days). At weaning, the rabbits in group PF showed higher values in caecal content (g 26.3 versus 22.6; P < 0.05) and volatile fatty acids (mmol/l 52.2 versus 43.6; P < 0.01) and lower values in empty caecal weight (g 7.18 versus 7.78; P < 0.05), C3 (6.4 versus 9.3%; P < 0.01) and C3/C4 ratio (0.39 versus 0.63; P < 0.01) than the group NPF. On the basis of the above results, it may be concluded that the quantity of solid feed and milk intake before weaning influenced the characteristics of the caecal content, but not the performance of rabbits around weaning.

A six-year investigation on reproductive performance of hybrid rabbits. 1. Pregnancy rate and numerical productivity at weaning as affected by season

Abstract With the aim to clarify the effect of seasonal variation on reproductive performance of hybrid rabbits, a six-years investigation was carried out. Traits analysed were pregnancy rate of does and numerical productivity at weaning. The data set included: 33588 matings and subsequent pregnancy diagnosis; 245743 young rabbits at weaning. From the statistical analysis, pregnancy rate and numerical productivity at weaning appeared to be significantly (P<0.001) affected by seasonal variation. Furthermore a statistically significant (P<0.001) month influence was also found. Nevertheless a correlation between the two parameters needs to be performed to supplement our analysis.

Interaction of reproduction rhythm, suckling and parity on mating incidence, ovarian dynamics and estrogen secretion in the rabbit doe

The effects of suckling and remating interval (11 or 21 d post partum) were studied in primiparous (P=25) and multiparous (M=23) hybrid rabbits. In P rabbits, suckling had no significant effect on mating incidence; however, a higher percentage of females accepted the male on d 11 than on d 21 (P<0.01). In M rabbits, no significant differences in mating performance due to either day, suckling or their interaction were found. A higher proportion of nonsuckled than suckled P rabbits ovulated (P<0.01). Ovulation incidence was not affected significantly by day of mating, suckling or their interaction in M rabbits. A comparison of the day influence in P and M rabbits on mating incidence showed a greater effect in the P (P<0.05) while the suckling effect on ovulation performance showed an insignificant difference in the two parity groups. Ovulation rate, as assessed by ultrasound, was not influenced significantly by day or suckling in either P or M rabbits. The follicle distribution was marked by fewer large follicles and lower plasma estrogen levels were detected in suckled than in nonsuckled P and M rabbits (P<0.05). Further research is needed to elucidate these phenomena also when AI is performed.

Influence of weaning age (28 vs. 63 d) on quantitative and qualitative carcass traits of rabbits

Riassunto Influenza dell’età di svezzamento (28 vs. 63 d) sulle caratteristiche quanti-qualitative delle carcasse di coniglio. Centonovantadue conigli sono stati equamente suddivisi in due gruppi sperimentali e svezzati rispettivamente a 28 e 63 giorni, e tutti macellati a 83 giorni di età. Dopo sezionamento delle carcasse, sulla carne ottenuta dallo spolpo dell’arto posteriore sinistro di 18 conigli per gruppo è stata determinata la composizione chimica, macro e microminerale, nonché quella acidica dei grassi da cui è stato possibile calcolare gli indici di aterogenicità e trombogenicità. I risultati ottenuti evidenziano le migliori qualità dietetico-nutrizionali delle carni dei conigli svezzati a 28 d: in particolare, sono stati più elevati i contenuti di ferro (1,25 vs. 0,93; P<0,01) e più favorevoli gli indici di aterogenicità (0,68 vs. 0,75; P<0,01) e trombogenicità (1,04 vs. 1,14; P<0,01).