Making More from Sheep Australian Wool Innovation Limited Meat & Livestock Australia
MODULE 10: Wean More Lambs
Procedure 10.5
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Background
information

Management of ewes for their next joining starts at weaning or with maiden ewes the previous winter. Important management tactics include:

Careful management of ewe nutrition after weaning to maximise condition score at joining.

Reviewing the previous year’s management calendar to identify any potential improvements to the management program.

Assess the condition of ewes at weaning and allocate feed resources depending on condition score. This simple management strategy will lead to naturally weaning more lambs. It is also the most economical way to ensure ewes are in good condition by next joining. Maintaining condition is the most efficient use of feed, as allowing sheep to lose weight and then having to feed supplements to regain condition requires three times more feed.

Cull any ewes with reproductive faults and determine the number of replacement sheep required for the next breeding season. This process may be influenced by planning for the future sheep enterprise mix between meat and wool production.

 

At a Glance
At weaning, draft ewes into condition score groups and allocate the best available pasture to those ewes below score 3.

pt Immediately after weaning, plan the grazing management up to next joining.

pt Select ewes on rearing ability to make gains towards weaning more lambs.
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Key decisions, critical actions and benchmarks

Maximise ewe condition score at the next joining

Wean lambs based on seasonal conditions or rule of thumb: Weaning lambs 14 weeks after the start of lambing is a fairly good rule of thumb if the joining period was around six weeks and you are experiencing an average season with available green feed. In most situations this will ensure that ewes are able to regain liveweight and body condition after weaning while pasture quality is at a satisfactory level. If the season is exceptionally good, ewes are in more than condition score 3 and lambs are growing well, it may be beneficial to extend the weaning date up to 18 weeks, provided worm burdens are carefully monitored.

However, in a very poor (drought) season there can be a significant benefit to both lambs and ewes by weaning as soon as 10 weeks after the start of lambing (for a 5 week joining period) and providing intensive management to both ewes and lambs. This may mean drafting ewes according to body condition, doing a feed budget on available pasture and providing supplements as needed to achieve target body condition for next joining. Weaning this early is likely to result in many lambs less than 24 kg at weaning. These weaners will require sufficient high quality feed or supplements to grow at more than 1 kg per month to avoid significant losses. Worm burdens will need to be carefully monitored and producers should be alert to potential trace element deficiencies.

Condition score ewes and draft into groups at weaning

At weaning use tool 10.1 to separate ewes into management groups with the lower condition score groups being allocated the best available pasture. This is a relatively simple, low cost/high benefit management strategy that is worth the investment of your time.

Ewes in low condition score will rapidly gain weight when grazing green feed. But ewes in low condition cost more to supplementary feed once pasture quality deteriorates. They will also have poorer reproductive performance and are at higher risk of losing their lambs at birth.

Selecting replacement adult ewes

Refer to procedure 9.3 in Gain from Genetics for recommended approaches to selection and breeding.

Selection for age

While reproductive performance can still be good in older ewes, death rates may be higher and fleece values lower. The optimum sale age for older ewes is between 4 and 6 years depending on flock structure, management plans and relative livestock values.

In non self-replacing breeding flocks the cost of replacement ewes influences the ideal sale age. Meat breed ewes are normally kept for 1-2 years longer than Merinos.

Dry Ewes

Ewes that fail to get in lamb in any one year have a low repeatability of failing to get in lamb the following year. However, ewes that fail to get in lamb 2 years in a row should be culled.

Select for rearing ability

Small, but consistent, gains can be made towards weaning more lambs by culling those ewes which lamb, but fail to rear their young. The ‘wet and dry’ technique (stripping fluid from the udder at lamb marking) is used to identify ewes that are either rearing a lamb or have lambed and lost. Ewes not rearing a lamb have some udder development but tend to have clear fluid and teats that are dirty. Dry ewes have no birth stain on the breech and little udder development.

The progressive gains from culling maidens that fail to rear a lamb include:

  • Ewes that reared as maidens rear 10% more lambs at subsequent lambing.
  • The ability to rear a lamb is passed on to subsequent generations, especially if ram selection includes maternal rearing ability.


Genetic selection for reproductive performance

Reproductive traits have low heritability so genetic gains are slow. Ewe liveweight is correlated with reproductive performance. Scrotal circumference in rams is correlated with ovulation rate in ewes. Setting breeding objectives in a commercial flock is discussed in procedure 9.2 in Gain from Genetics.

In terminal sire breeding flocks where ewe replacements are purchased, consider freedom from disease and genetic merit when determining the purchase price. Use all the genetic information available from ewe and ram databases (from LAMBPLAN ASBVs) to make decisions when purchasing replacement ewes (see tools 9.3 and 9.6 in Gain from Genetics).

Signposts Signposts

Read

Lifetimewool Ewe Management Handbooks for your region. Available from www.lifetimewool.com.au

Lambing Planner - Vitual Shepherd version 3. The lambing planner is a useful tool to help manage the breeding cycle. Order a copy from the MLA website by searching for Lambing Planner at: www.mla.com.au/home. Free to members and $15.00 for non-members

View

Reproduction - managing my ewe flock. Visit this section of the Sheep CRC website, which can be found under the Industry, Tools & Information tab on the home page at: www.sheepcrc.org.au

Analysis of the profitability of wool and meat enterprises Final Report 1.2.6 – guidelines (biological and economic) for sheep producers to optimise profit and minimise risk, which can be adapted to suit a range of environments. Visit: www.sheepcrc.org.au/images/pdfs/CRC1/CRC1_Wool/GrassGro/GrassGro_Resultsfinalv2.pdf

Attend

Managing Pregnant Ewes workshop, hosted by your local pregnancy scanning contractor and the Sheep CRC

Contact your state Making More from Sheep co-ordinator to host a workshop or visit www.makingmorefromsheep.com. au

 

 

 

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