EFFECTS OF DIETARY ENERGY DURING GESTATION AND LACTATION ON REPRODUCTIVE-PERFORMANCE OF SOWS - A COOPERATIVE STUDY

A cooperative experiment involving 999 litters was conducted at seven stations to assess the reproductive performance of gilts and sows fed different levels of energy during gestation and lactation (21 d) for t hree consecutive parities. Treatments consisted of two gestation (G) a nd two lactation (L) diets in a 2 x 2 factorial arrangement. Gestation treatments were diets fed to provide normal (5.9 Mcal/d, NG) or high (7.4 Mcal/d, HG) energy intake; lactation treatments were diets that c ontained 0 (NL) or 9% added fat (HL). Sows were provided ad libitum ac cess to feed during the lactation period. Feeding the higher energy le vel during gestation increased pig birth weight (P < .01) and pig weig ht gain to weaning (P < .01). Sows that had been fed the higher level of energy during gestation (HG) ate less feed during lactation (P < .0 1) and lost more weight during lactation (P < .01). Increasing lactati on energy intake by adding fat resulted in greater pig weight gains to 21 d of age (P < .01). Sows fed the HG-NL combination had fewer pigs on d 21 than all other treatment groups (G x L; P < .01). There was a G x L x parity interaction (P < .05) for days to estrus after weaning. Sows on the NG-HL or HG-NL treatments had increased days to estrus in Parity I (P < .05); whereas those on the NG-NL treatments had increas ed days to estrus in Parities 2 and 3 (P < .05). The HG-HL treatment m inimized days to postweaning estrus during the three-parity study. The se data demonstrate that the levels of energy fed during different pha ses of the reproductive process have interactive effects on reproducti on performance of sows.