<?xml version="1.0" encoding="US-ASCII"?>
<!-- Generated by CompSci Transform (tm) - http://www.compsciresources.com -->
<!-- Created: Tue Mar 24 22:40:44 UTC 2026 -->
<linkbase xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:xbrldt="http://xbrl.org/2005/xbrldt">
  <roleRef xlink:type="simple" xlink:href="crl-20251227.xsd#crl_r_AdditionalDimensions" roleURI="http://www.criver.com/role/AdditionalDimensions"/>
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default"/>
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain"/>
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension"/>
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member"/>
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" arcroleURI="http://xbrl.org/int/dim/arcrole/all"/>
<!-- [WMV6][rS3CzOOhXR4MvDGVDkONd6YpCKpHFJjJW08gtkCoisKNF4W7e+ikFIVztvxvxwe6EXIXSkfzdxsUgsInsaFxlh810VSHBpgmmE++OJQ3NDhw+xOV+0cn0S5+4MdWsMqnAQIPjQfFTUchJ3glFTGYNUT64nTyofzRLA94aZzhMLl5Qh6Bpw/mjN7kp6+V1oGGci/F3l7mG5IB0sEk82Ame7oxCYIhV7t2jOI0mX2R4gNlVMc5M1GgSYmf2I+TCLecbPKiZ43u/KkVO36NiiJ4hy6xzx7TokjuPDcJM1RHil+RtVAtJ5sOgufwcMMdmJJtdxxUdVPVjnEKEstTVhGW] CSR-->
  <definitionLink xlink:role="http://www.criver.com/role/AdditionalDimensions" xlink:type="extended"/>
</linkbase>
