Available Online: http://www.ejpau.media.pl/volume14/issue3/abs-08.html
BIOLOGICAL LIMITS OF FECUNDITY IN SOWS – DO THEY EXIST?
Klaus-Peter Brüssow1, Martin Wähner2, Jêdrzej M. Ja¶kowski3
1 Leibniz Institute for Farm Animal Biology (FBN) in Dummerstorf
2 Anhalt University of Applied Sciences in Bernburg
3 University of Life Sciences in Poznañ
The profitability of pig production considerably depends on the number of born alive and fostered piglets. Therefore, it could be of interest to estimate the reproductive potential of sows. The progress regarding the number of piglets born for German Landrace, Large White and Pietrain in Germany during 1970–2006 is still moderate (GL: 10,4–11,0; LW: 11,0–11,0; PI: 10,2–10,0). Comparing actual international data, variations between 11.3 to 14.2 piglets born alive are observed. The reproductive performance of sows is mainly determined by (i) the number of ovulated follicles and fertilized oocytes, (ii) the percentage of surviving embryos and fetuses, and (iii) the morphological and functional performance of the uterus to support fetal development until birth. Therefore, the question whether the ovary and/or uterus are limiting factors will be discussed. Although only less than 0.1% of oocytes present in the ovary are ovulated during the sows' lifetime, the pool of ovarian follicles is not the limiting one. Selection for ovulation rate increases the number of ovulating follicles, but not of piglets born alive. Limited uterine capacity and function seems to exert greater influence. Although a relationship exists between uterine dimension and the number of fetuses/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. At present, the (realistic) presumed potential of fecundity is 16.0 piglets born alive, 2.4 litters/year, <10% losses and 34.0 piglets per sow/year (compared to current data of 12.2, 2.33, 14.8 and 24.2, respectively).
Key words: Pig, fecundity, ovulation, uterus.
Leibniz Institute for Farm Animal Biology (FBN) in Dummerstorf
Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany
Anhalt University of Applied Sciences in Bernburg
Strenzfelder Allee 28, 06406 Bernburg, Germany
Jêdrzej M. Ja¶kowski
University of Life Sciences in Poznañ
ul. Wojska Polskiego 52, 60-625 Poznan, Poland
phone: 605 436 438
Responses to this article, comments are invited and should be submitted within three months of the publication of the article. If accepted for publication, they will be published in the chapter headed 'Discussions' and hyperlinked to the article.