Ewe wastage and udders

• Ewe wastage


  Ewes that do not survive and be productive until culled for age
• Longevity


  The ability of a ewe to survive and be productive until culled for age
• Higher number of replacements are required with higher ewe wastage rates
• Higher ewe wastage rates lead to lower flock reproductive performance and milk production, and extra feed going into more replacements for little return
• On-farm annual mortality in NZ varies between farms (2.8 – 15.7%) but there is scant recent information
• The industry often 'talks' about a typical flock rather than individual ewe data or even good accurate flock data
• Causes of thin ewes

  1. Necropsied at scanning

  2. Longitudinal study to establish extent & timing of ewe wastage, and identify phenotypic factors associated with reduced longevity & increased wastage
• As a % not many ewes make it to the expected culling for age stage
• Ewes are going from the system in all age groups
• Ewe losses are high during the period from pregnancy diagnosis to weaning
• Ewe losses in the period from pregnancy diagnosis to weaning contribute to lamb losses
• This is the period of greatest metabolic demand for ewes
• Approximate losses over the calendar year: -3 ewes (dry/dry), -4 ewes (wet/dry), -16 ewes (culled for various reasons), -6 ewes (dead/missing), -1 ewe (culled other reason), 30 replacements required
• Potential lost lambs per 100 ewes (average) due to wastage is an underestimate as it does not include all lamb deaths where one of a twin or one or two of triplets died
• Ewe wastage is a large problem on many farms, being a combination of premature culling and ewe deaths/missing
• High wastage impacts overall flock performance and profitability
• Ensuring ewes are in good body condition score should reduce wastage
• Non-pregnant ewes and those that fail to rear lambs successfully are large drivers of premature culling
• Ewe udder health


  Lambs depend on their dams milk for survival & growth
• Surveys indicate 85% farmers examine ewes udders but there is no standardised scoring method available and impacts of a 'poor' udder on production are poorly understood
• MU study design


  1. Commercial flock of approx. 1,200 ewes enrolled

  2. Range of udder and teat scores measured (visual & palpation)

  3. Undertaken at key management times (4 times per year)

  4. Lambs matched to dams
• Relationship between lamb growth to weaning and dam premating udder palpation, udder depth, clinical mastitis and udder symmetry scores
• Udder defects are relatively common in mixed aged ewes (2-7% affected)
• It is better to examine ewes' udders 4-8 weeks post-weaning than at weaning
• Most palpable udder defects are associated with production losses