Neuroendocrinology applied to rabbit breeding

Abstract

Successful rabbit production relies heavily on the use of adequate practices that enhance specific aspects of reproduction, such as mating, ovulation and lactation. Regardless of the type of production unit or strain of rabbits used, these processes rely on a complex chain of neuroendocrine steps that include particular hormones, peripheral stimuli and activation of discrete brain regions. Such is the case, for instance, of reflex ovulation, which occurs in response to copulation but is inhibited throughout lactation. Little is known about the mechanisms mediating lactational anoestrus and the restoration of oestrus following the cancellation of a single suckling episode (biostimulation). Nevertheless, the latter procedure (adopted worldwide to accelerate reproduction) has unwanted consequences for the doe and her litter. After successive episodes of biostimulation, the former shows a loss of fertility and body mass. In the kits, alterations are observed in their neuroendocrine response to mildly aversive stimulation in adulthood, as well as reductions in sexual behaviour. In addition to milk intake, a good nest is essential for normal litter growth and development. If this is not available, or if it deteriorates, rabbit caretakers can easily (re) build one from hair sheared off other rabbits or using synthetic material. Lactating does will nurse equally well their own or ‘alien’ young, placed inside the nest. It is crucial to have a minimum of six suckling kits in the nest, as the doe relies on this stimulation to maintain a normal nursing behaviour, i.e., only once a day throughout lactation. Recent work is revealing the similarities and differences in the responsiveness to mating among oestrous, lactating and biostimulated does. The relevance of these findings for the likelihood of reflex ovulation and the additional contribution of factors contained in the semen warrant more in-depth research. New insights on these issues, essential to reproductive neuroendocrinology, can emerge by fostering a richer interaction between academic laboratories and rabbit production settings worldwide.

Composition of the Wild Rabbit Nest and Its Implication for Domestic Rabbit Breeding

“…We have found a remarkably small variation in the composition of both the wild rabbit nests and the laboratory constructed nests suggesting that rabbit nest building is a result of tightly controlled mechanisms [43,51]. While our tests were restricted to the beginning of the nest building, and the plant components are usually collected during several days preceding the parturition [51], we were able to demonstrate that even the initial plant choice indicates clear preferences toward features present in wild rabbit nests.…”

“…A well-constructed nest may increase the survival of the offspring and provide long-term benefits to the mother in the wild but is seemingly less important under controlled laboratory settings [36,41]. Remarkable specialization in the physiological mechanisms underlying the above reactions is known for this species [42,43]. Mimicking the ancestral situation in the rearing is still plausible [41] and can improve the welfare status of rabbits [44].…”