Chapter 10.5 Prepare your ewes for next joining
Background information
Management of ewes for next joining starts at weaning. Important management tactics include:
- Careful management of ewe nutrition after weaning to maximise condition score (CS) 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 CS. 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.
Identify any ewes with reproductive faults and determine the number of replacement sheep required for the next breeding season.
At a glance
- At weaning, draft ewes into CS groups and allocate the best available pasture to those ewes below score 3.
- Immediately after weaning, review your grazing management plan up to next joining.
- Select ewes on rearing ability to make gains towards weaning more lambs.
Maximise ewe condition score at the next joining
Wean lambs no later than 14 weeks after the start of lambing if you are experiencing an average or good season with available green feed. In most situations this will ensure that ewes are able to regain body condition after weaning while pasture quality is at a satisfactory level.
However, in a poor (or drought) season there can be a significant benefit to both lambs and ewes by weaning at 10 weeks after the start of lambing (for a 5 week joining period) and providing preferential management to both ewes and lambs. For ewes, this means drafting ewes according to CS and feed budgeting to understand your available pasture, pasture and ewe growth rates and whether supplementary feeding is required to achieve target CS for next joining. Early weaning is likely to result in many lambs less than the target weaning weight of 45% standard reference weight (SRW, see tool 10.7) at weaning. These weaners will require high quality feed/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, CS ewes (see tool 10.1 ) and draft those below CS 3 into a separate management group for preferential grazing on pasture, or if pasture quality is low, feeding a supplement to increase condition. Pasture is usually the only economic option for increasing ewe CS after weaning, and this is a relatively simple, low cost/high benefit management strategy that is worth the investment of your time. The target is to get all ewes up to score 3 or better by joining (see chapter 10.1).
Weaners and lactating ewes rearing twin lambs should get the best pastures, followed by single lambing ewes, pregnant ewes, hogget ewes, and then wethers and dry ewes (shown in figure 10.6).
Figure 10.6 Prioritise your available feed depending on the classes of stock you have.
Source: AWI Winning With Weaners
Ewes in low CS 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 reduced reproductive performance and are at higher risk of losing their lambs at birth or having poor lactation and unsatisfactory lamb growth rates.
Selecting replacement adult ewes
Refer to chapter 9.3 and chapter 9.4 in MMFS Module 9 Boost Business with Breeding from recommended approaches to selection and breeding.
Selection for age
While reproductive performance is still good in older ewes, in some cases death rates may be higher and fleece values may be lower. The optimum sale age for ewes depends on your flock structure, management plans and relative livestock values. In breeding flocks that buy in ewes, the cost of replacement ewes also influences the ideal sale age.
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. The decision to sell dry ewes will be heavily influenced by your flock structure, ewe numbers (increasing vs. steady) and the percentage of ewes that are dry. In any case it is a good practice to ask yourself, “is it her fault or mine?”.
If a ewe fails to get in lamb twice in her breeding life, she should be removed from the replacement breeding flock.
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 drying’ technique (checking ewes’ udders at lamb marking) is used to identify ewes that are either rearing a lamb or have lambed and lost. Ewes who are rearing a lamb will have a full, warm udder with clean teats. Ewes who have lambed and lost generally have birth stain on the breech and 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 wet and drying and making selection decisions based on reproductive performance include:
- Ewes that reared as maidens rear 10% more lambs at subsequent lambing.
- Ewe rearing ability is repeatable, meaning the ewes in your flock that successfully rear lambs are more likely to do it year after year.
Genetic selection for reproductive performance
Reproductive traits have low heritability so genetic gains are slow, but cumulative. ASBV traits available for reproduction include conception (CON), litter size (LS) and ewe rearing ability (ERA). This allows you to focus on the traits which will lead to the most improvement in your flock if there is a specific aspect of reproduction you’d like to improve or you can use all of them if that fits with your breeding objective.
Direct measures of reproductive performance are the most reliable and are the preferred way of making genetic improvement to reproduction, but they can be expensive and difficult to collect for some ram breeder’s and commercial flocks. If genetic improvement in reproduction is important to you, it will prove an important part of your ram source selection criteria. Direct measures that can be utilised on-farm include pregnancy scanning and wet and drying at lamb marking.
Examples of indirect measures for reproductive performance that can be used in a commercial flock include ewe liveweight and ram scrotal circumference. Ewe liveweight is related to reproductive performance but needs to be optimised and considered with regard to stocking rate and work health and safety (on-farm staff and shearers). Scrotal circumference in rams is related to ovulation rate and litter size in their daughters.
In breeding flocks where ewe replacements are purchased, consider freedom from disease, their fit with your management calendar and breeding objective and genetic merit when determining the purchase price. Use all the genetic information available from ewe and ram sources to make decisions when purchasing replacement ewes (see chapter 9.5 in MMFS Module 9 Boost Business with Breeding).
Setting breeding objectives in a commercial flock is discussed in chapter 9.4 in MMFS Module 9 Boost Business with Breeding.
SIGNPOSTS
The first season of AWI Change Makers is a ten-part video series centred around sheep reproduction. Tune in to hear leading livestock consultant, Nathan Scott, demonstrate a range of practical ways growers can influence sheep reproduction with the latest research and tools informed by the AWI-funded research and development outcomes. Episode 2 – Weaning to manage Episode 4 – Ewe condition scoring Episode 5 – Joining timing and length
The interactions between pasture growth patterns, stocking rate, time of lambing and production are complex. The guidelines outlined in these handbooks give wool producers an optimum strategy for managing ewes ‘year in, year out’ to maximise production, ensure healthy ewes and deliver efficient feed allocation.
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Ewe nutrition is crucial to successful lambing. Knowing what and when to feed ewes is fundamental to ewe and lamb health and survival. Understanding pasture allocation for single and twin bearing ewes and identifying the need to supplementary feed are important considerations for woolgrowers.
Ewe reproduction is measured by the capacity to conceive and rear lambs to weaning each season following puberty. This is influenced by the timing of joining and lambing and paddock allocation. Once these factors have been decided, ongoing ewe management, particularly ewe body condition score, plays an important role in determining reproductive success.
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Assists sheep producers to proactively manage the nutrition of their ewe flock through the reproduction cycle utilising condition scoring and feed on offer (FOO) assessments.
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The course is delivered in small groups of 5-7 sheep producers that meet six times per year with a professional trainer. During these hands-on sessions, the group visits each participating farm and learns skills in condition scoring, pasture assessment and best practice ewe and lamb management to increase reproduction efficiency and wool production, mainly through reducing ewe and lamb mortality.
A practical, one-day workshop highlighting the key production benefits of superior genetics, plus feed management for improved reproductive performance and livestock productivity.
Designed for woolgrowers and is aimed at improving weaner management of their Merino flock, targeting 95% weaner survival to one year of age. WWW identifies key practical actions and tools for commercial enterprises to implement on farm to achieve this performance aim.
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