The influence of weaning age on growth and development of the baby pig and reproductive efficiency in the sow

Abstract

Thirty-nine litters containing 385 pigs of mixed breeding were weaned at 1, 7, 14, 21, 28 or 35 days of age in two experiments conducted during the spring and summer of 1966 . A creep ration constituted the only diet from weaning to 56 days with the exception of pigs weaned at 1 or 7 days. These pigs were given a reconstituted “milk” in addition to creep feed from weaning to 14 days of age. An interaction between litter size and length of the nursing period on rat of ga in and feed efficiency was observed in both experiments. Early weaning increased rate of gain in large litters and improved feed efficiency except in the 1-day treatment groups.

Data on estral behavior and efficiency of reproduction were obtained from the same sows that farrowed the litters used in these experiments. These data indicate that normally a fertile estrus can be expected within seven days following weaning as early as seven days post-partum and that breeding will produce a pregnancy. Subsequent litter size appeared to favor later weaning. Estral behavior was aberrant in Experiment II and appeared to be directly related to high environmental temperature. Uterine pathogens appeared to adversely affect placentation and/or embryonic survival.