A number of studies have documented that litter size (number born) in primiparous sows is
larger than that in gilts and that litter size increases through the fourth or fifth pregnancy
(Carmichael & Rice, 1920; Lush & Mollin, 1942; Olbrycht, 1943; Perry, 1956; Lynch, 1965).
The ability of multiparous females to produce larger litters than primiparous females is generally
attributed to two factors: age and previous reproductive experience (parity). However, most data
relating age and parity to litter size have been collected under normal production conditions in
which the two factors are highly confounded. Determining the relative contribution of age and
previous reproductive experience to litter size is of considerable importance in directing future
research on uterine and ovarian factors which affect fecundity of swine. Therefore, an
experiment was conducted to determine if prior reproductive experience had a beneficial effect
on litter size which was in addition to the effect of age of the dam.
Materials and
 
A number of studies have documented that litter size (number born) in primiparous sows islarger than that in gilts and that litter size increases through the fourth or fifth pregnancy(Carmichael & Rice, 1920; Lush & Mollin, 1942; Olbrycht, 1943; Perry, 1956; Lynch, 1965).The ability of multiparous females to produce larger litters than primiparous females is generallyattributed to two factors: age and previous reproductive experience (parity). However, most datarelating age and parity to litter size have been collected under normal production conditions inwhich the two factors are highly confounded. Determining the relative contribution of age andprevious reproductive experience to litter size is of considerable importance in directing futureresearch on uterine and ovarian factors which affect fecundity of swine. Therefore, anexperiment was conducted to determine if prior reproductive experience had a beneficial effecton litter size which was in addition to the effect of age of the dam.Materials and
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