Reproduction performances and conditions of group-housed non ...

- Appendix 1 -
APPENDIX 1
LITTER SIZE AND FARROWING RATE, WHICH PHYSIOLOGICAL PROCESSES
MAY GO WRONG AND WHY?
Successful reproduction, characterized by establishment and maintenance of pregnancy and
a high litter size, depend on a series of precisely timed physiological and endocrine events
in the period from weaning to farrowing. Some of these events are illustrated in Figure 1
and will be explained in the following text.
Day 117
Day 13-25
Posterior pituitary gland Anterior pituitary gland Developing follicles Uterus Corpus Luteum
Oxytocin
Maintenance of pregnancy
Implantation of ova in the
uterus
+ fertilisation
Farrowing
The mature ova pass
down into the uterus
Day 3.5
FSH LH Oestrogen Prostaglandin Progesteron
Weaning
÷ fertilisation
Regression of
corpus luteum
The ruptured follicles
form corpus luteum
Release of the mature ova
(=ovulation)
The physiological events will be discussed in events happening 1) before and around mating/insemination
and 2) after mating/insemination. After that the endocrine control of the
physiological events will be presented. Finally, a short discussion of which parameters may
influence these events will be carried out.
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Development and maturation
of ovarian follicles
Day 1
Mating/insemination
Transport of semen
Oestrus behaviour
Figure 1. Reproduction related physiological and endocrine events in the period from weaning to
farrowing (see text for further explanation)
Day 0