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Understanding & Reducing Within-litter Variability In Piglet Birthweight

Published: Thu, 06 Jan 2005

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Research Note Full Title

Understanding and reducing within-litter variability in piglet birthweight

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Many pig litters contain at least one piglet that is significantly lighter than its littermates.  Such low birthweight piglets present welfare, management and carcass quality problems.  Low birthweight piglets often fail to thrive and are more likely to die soon after birth.  Those that do survive grow more slowly and reach a lower mature body size with increased carcass fat.

Low birthweight piglets increase the range of birthweights within a litter.  Such variability in itself a problem for contemporary pig management systems.

Objectives

As there are few opportunities to remedy the detrimental effects of low birthweight after birth, our research aims to understand the timing and causes of fetal growth retardation and hence identify opportunities to reduce low birthweight.

Approach

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By comparing fetal and placental function in inadequately grown and normally grown fetuses carried by the same mother, we can identify intrinsic factors associated with fetal growth retardation.

Outcomes

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Achievements

  • Developed a robust model to study naturally occurring fetal growth restriction in the pig.
  • The incidence of inadequately grown fetuses on Day 30 of pregnancy is the same as at term, suggesting that the range of fetal weight is established during the first month of pregnancy.
  • Placentas supplying inadequately grown fetuses are less able to transport the essential amino acid leucine.  The change in the type of placental amino acid transporters that occurs in placentas supplying normal-sized fetuses either does not occur, or is delayed, in placentas supplying inadequately grown fetuses.
  • Concentrations of important metabolic hormones differ between normal sized and inadequately grown fetuses in the same mother, contributing to the poor post-natal outcome observed in small piglets.

      • Implications

      This research has shown that strategies that promote within-litter uniformity during the first month of pregnancy may be most effective in reducing the incidence of low birthweight pigs and variation in within-litter birthweight.

      Increasing the number of pigs reared per sow per year from 22 to 23 is estimated to deliver a cost benefit of 1.1 p/kg DW to the UK industry.

      Sponsors & Partners

      Research Sponsors

      The Scottish Government (formerly SEERAD)

      Research Partners

      Rowett Research Institute, University of Aberdeen