A New Method of Litter Equalization in Rabbit

TL;DR

A new method of grouping newborn rabbits by birth weight reduces mortality and improves weight uniformity at slaughter.

Contribution

A novel litter-equalization method is proposed to reduce low-weight rabbit mortality and improve slaughter weight homogeneity.

Findings

Grouping low-weight kits reduced mortality from 20.0% to 8.9% in the first 7 days.

The new method slightly improved slaughter weight homogeneity but had no effect on dressing out percentage.

No significant weight differences were observed among experimental groups at 84 days.

Abstract

In order to achieve uniform appearance of the carcass and parts of the carcasses, it would be optimal if all rabbits weighed the same at slaughter. However, fattening lasts until a certain age, i.e., 11 weeks, at which time the rabbits’ body weight varies greatly. It is desirable to reduce this variation. In practice, the mortality of rabbits born with a low weight is reduced by placing kits of similar birth weight in one litter, forming separate litter groups of kits having low, medium, and high birth weights, respectively. In the experiment, the authors investigated the advantage of placing 9 low-weight, 10 medium-weight, and 11 large newborn rabbits in a litter. According to the results, fewer rabbits born with a low weight died, but the slaughter weight homogeneity of the rabbits improved only slightly.

On rabbit farms, the mortality of rabbits born with a low weight is high, and there is a large variation in body weight, so the carcass and the cut carcass are not uniform. The experiment aimed to reduce the mortality of kits born with a low weight and to produce more-uniform slaughter animals. In the experiment, each rabbit doe in the Control group raised 10 newborn kits with low birth weights (S10, n = 100), 10 with medium birth weights (M10C, n = 100), or 10 with high birth weights (L10, n = 100). In the Experimental group, the rabbit does raised 9 newborn kits with low birth weights (S9, n = 90), 10 with medium birth weights (M10E, n = 100), or 11 with high birth weights (L11, n = 110). Compared with the S10 group, the mortality (between 0 and 7 days) in the S9 group was reduced (20.0% vs. 8.9%; p < 0.001). While the body weights of the S10, M10C, and L10 subgroups in the Control group increased at 84 days (2876 g, 2872 g, and 3047 g, respectively), there was no significant difference in the body weights of the three subgroups (S9, M10E, and L11) in the Experimental group. The new litter-equalization method was therefore suitable for reducing mortality and achieving a more-equal slaughter weight. At the same time, there was no difference between the groups in the dressing out percentage. The authors further suggest considering the teat number of the does and raising low-weight kits in litters of eight.

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