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Unformatted text preview: 1 ISU Successful Breeding & Management of Pregnancy AnS 225 Spring 2012 ISU Breeding and Gestation Management Program Maximize • Number of pigs/litter • Litters/year • Lactation yield Optimize • Pig birth weight • Sow longevity • Lifetime productivity ISU Critical Periods for Successful Breeding and Gestation Rebreeding 4-? days Gestation 114 days Farrowing Weaning Breeding Lactation 14-28 days Day 0 Fertilization Day 1-12 Embryos are “free floating” Day 11-14 Maternal recognition of pregnancy Day 14-30 Implantation of fetus Day 84-114 Stress increases stillborns Day 30-114 Gestation weight gain. Pregnancy detection 3 ISU Embryonic Losses Eggs Shed 20 Eggs Fertilized 19 Embryos at d 30 14 Fetuses at 100 d 11 Pigs Born Alive 10 Pigs Weaned 9 30% Loss 50% Loss ISU 5 Goal in Gestation Management Should be “Stress Reduction” ISU Critical Periods for Successful Breeding Weaning to Estrous Fighting & high temperatures reduce feed intake which can lead to longer wean-estrus intervals and reduced ovulation rate. Maintain temperatures <85 F to stimulate feed intake. Day 0 Fertilization takes place on Day 0. Heat stress on the female or male can negatively affect fertilization rate. Days 1 - 12 Embryos are “free-floating” & are susceptible to stress from heat and unnecessary movement. Days 11 - 14 Maternal recognition of pregnancy occurs and progesterone is secreted to maintain pregnancy. Days 14 - 30 Implantation of the fetus occurs. Failure to maintain an adequate attachment results in fetal death. Females should not be unnecessarily handled at this time, to promote good fetal attachment with the placenta. 6 2 ISU Physiological Factors Weaning to First Service Interval • If adverse metabolic conditions persist, then estrus will be delayed Increased energy intake from weaning to mating speeds return to estrus • Particularly in Thin or Parity 1 and 2 females 10 20...
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- Spring '08