title: Estimation of lifetime productivity of female swine.
abstract: OBJECTIVE
  To develop estimates of lifetime productivity for breeding female swine calculated longitudinally during time in the breeding herd, and to compare estimates of lifetime productivity for female swine removed from the herd at different parities.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  9,416 breeding female swine from 29 herds.
  
  
  METHODS
  A frequency distribution for parity at the time of removal was generated. Estimates of lifetime productivity (lifetime nonproductive days [NPD], lifetime NPD as a proportion of herd life, total number of pigs born per litter weaned, number of pigs born alive per litter weaned, number of pigs weaned per litter weaned, number of NPD per year in the herd, number of litters weaned per year in the herd, and number of pigs weaned per year in the herd) were calculated for females with parity > or = 1 at the time of removal.
  
  
  RESULTS
  For 58% of all females, parity at the time of removal was < or = 3. On average, 20.7% of herd life was spent in nonproductive activities, but the proportion of herd life that was nonproductive decreased significantly as parity at the time of removal increased. Number of NPD per year in the herd decreased and number of litters weaned per year in the herd and number of pigs weaned per year in the herd increased significantly as parity at the time of removal increased.
  
  
  CONCLUSIONS
  Higher parity at the time of removal from the herd is associated with improved lifetime productivity for female swine. Parity at time of removal is commonly used as an approximation for lifetime productivity, but it does not take into account the impact of NPD, especially NPD during early reproductive cycles.
authors: Department of Clinical and Population Sciences, College of Veterinary Medicine, University of Minnesota, St Paul 55108, USA.
authors: T
authors: T
authors: Lucia
authors: G D
authors: GD
authors: Dial
authors: W E
authors: WE
authors: Marsh
mesh_terms: D000818:Animals; D015331:Cohort Studies; D005260:Female; D008098:Litter Size; D010298:Parity; D012098:Reproduction; D012189:Retrospective Studies; D013552:Swine / Q000502:physiology*; D014886:Weaning