Changes induced by the catabolism and the degree of
lactational catabolism influence follicle growth and
development, and the quality of oocytes. In the study of
Zak et al. (1997) primiparous lactating sows with feed
intake restricted to 50%, from day 22 to 28, had fewer large
follicles and a reduced ability of follicles to support the
oocyte maturation than did sows with a intake restricted to
50%, from farrowing to day 21, and then fed to appetite
from day 22 to 28. First parity sows that lost the most
protein in lactation had fewer larger sized follicles at
weaning, a smaller preovulatory follicle pool size and
follicular fluid less able to support nuclear and cytoplasmic
maturation of oocytes in vitro (Clowes et al., 2003a,b). A
lower conception rate, in sows with accentuated lactational
catabolism, may result from less healthy follicles
(Bracken et al., 2003) producing a bad quality corpus
luteum to maintain the pregnancy. In addition, lower
quality oocytes can fail to be fertilized or become embryos
of poor quality which die or are unable to produce an
adequate signal to maintain the pregnancy.
Changes induced by the catabolism and the degree oflactational catabolism influence follicle growth anddevelopment, and the quality of oocytes. In the study ofZak et al. (1997) primiparous lactating sows with feedintake restricted to 50%, from day 22 to 28, had fewer largefollicles and a reduced ability of follicles to support theoocyte maturation than did sows with a intake restricted to50%, from farrowing to day 21, and then fed to appetitefrom day 22 to 28. First parity sows that lost the mostprotein in lactation had fewer larger sized follicles atweaning, a smaller preovulatory follicle pool size andfollicular fluid less able to support nuclear and cytoplasmicmaturation of oocytes in vitro (Clowes et al., 2003a,b). Alower conception rate, in sows with accentuated lactationalcatabolism, may result from less healthy follicles(Bracken et al., 2003) producing a bad quality corpusluteum to maintain the pregnancy. In addition, lowerquality oocytes can fail to be fertilized or become embryosof poor quality which die or are unable to produce anadequate signal to maintain the pregnancy.
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