Lambing Growth

• Lactation


  The period when a female mammal produces milk to feed her young
• Nutrition during lactation


  1. During the first three weeks, lamb is solely dependent on milk

  2. From this period, lamb starts to increase intake of herbage

  3. Maximising ewe milk production has large impact on lamb survival and weaning weight
• Ewe milk production


  Affects lamb survival and weaning weight
• Heavier weaning weights improve profitability
• Advantages from increasing lamb weaning weight

  • 1 kg increase = 5-6% more lambs sold prime straight off mum at 17 kg carcass weight
  • 2 kg increase = $15,420 extra revenue
  • 3 kg increase = $23,130 extra revenue
  • 4 kg increase = $30,840 extra revenue
• Milk production


  Affected by level of dam nutrition in pregnancy and lactation, ewe condition/nutrition, number and size of lambs, breeds/genetics, quality of feed, ability to choose
• Milk production of single-suckling ewes

  Higher than twin-suckling ewes
• Calculating lamb growth rates at 4 weeks of age

  1. Determine milk intake and pasture intake

  2. Calculate total ME intake

  3. Determine growth rate
• Twins are limited by amount of feed they can consume, so they need more milk to grow faster
• Late pregnancy nutrition


  Affects colostrum yield, peak milk yield, and 6 week milk yield
• Poor nutrition in late-pregnancy and lactation results in lower peak and total milk production, especially in poorer condition ewes
• A twin bearing ewe does not produce twice as much milk as a single bearing ewe
• Ewe requirement in lactation

  • Single suckling ewe requires 2.65 kg DM/day at week 3
  • Twin suckling ewe requires 3.01 kg DM/day at week 3
• Pasture allowance


  Affects lamb grazing behaviour, ewe milk production, and lamb growth rate
• Nutrition during lactation to maximise milk production


  • High pasture allowance levels (6 kg DM/day)
  • Pasture masses between 1200 - 1800 kg DM/ha and sward heights of 4 – 8 cm
  • High quality pasture (high ME and palatability)
  • Ideally with a high legume content
• Poor feeding in pregnancy results in lower milk production, impacting weaning weights
• Poor feeding in lactation that results in ewes in poor condition at weaning is more likely to impact reproductive performance the following year
• Using 'alternative herbages' in lactation

  • Herb/clover mixes and Lucerne
  • Graze at 8 - 10 cm sward height
  • Set stock for lambing then start rotating post tailing
  • Careful with stocking rates
• Other factors affecting weaning weight

  • Birthweight
  • Breed effects
  • Sex of lamb
  • Genetics
  • Health status of dam and/or lamb
  • Weather
  • Husbandry practices
• Factors affecting timing of weaning

  • Average parturition date and age of lambs
  • Feed supply and feed quality
  • Stock density
  • Weight of lambs
  • Husbandry factors
  • External factors
• Lamb weaning strategies


  1. Calculate ewe and lamb DM requirements at different weeks of lactation

  2. Identify benefits of early weaning if feed is limited
• Requirements for early weaning

  • Lambs should ideally be 25 – 30 kg at weaning, although can be as light as 18 kg
  • Wean onto legume dominant pasture
  • Ensure high herbage allowance
  • Ensure no mineral deficiency issues
  • Have appropriate internal parasite control program
• Skim-draft weaning


  Allows for heavy lambs to be sold direct to slaughter, saves feed for other stock, and allows ewes to gain condition