Biological potential of fecundity of sows
2009
Waehner, M., Anhalt University of Applied Sciences, Bernburg (Germany) | Bruessow, K.P., Research Institute for the Biology of Farm Animals, Dummerstorf (Germany)
The profitability of pig production considerably depends on the number of born alive and fostered piglets. The development regarding the number of piglets born for German Landrace (DL), Large White (DE) and Pietrain (PI) in Germany during 1980-2006 is limited (DL: 10.4 - 11.0; DE: 11.0-11.0; PI: 10.2-10.0). Comparing international data, variations between 10.2 to 13.6 piglets born alive are observed. The pool of ovarian follicles is not the limiting one, although only about 0.5% of oocytes present in the ovary are ovulated during the sows lifetime. Selection for ovulation rate increases the number of ovulating follicles, but not of piglets born alive. Limiting is uterus capacity. This physical, biochemical and morphological limitation of the uterus include space, nutrients, gas exchange and surface of the placenta. Although a relationship exists between uterine dimension and the number of foetuses/piglets, uterine length alone is not a prerequisite of higher uterine capacity. Placental efficiency and the degree of placental blood supply appear to be essentially for litter size.
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