Tup Ewe Lambs
In this news article This farming, Stephen Flanagan, CAFRE beef and sheep adviser, explores the question on many farmers’ minds: should I dip my ewe lambs this year?
This is something many farmers toy with the idea of coming up with a normal tupping time in October and November.
In fact, you should ask this question at weaning to allow that animal to be properly managed before the balls go off.
With replacements higher than average this year, many farmers are considering keeping more ewes rather than selling them as root lambs.
With good feeding and nutrition, ewe lambs can improve the financial sustainability of sheep systems and reduce the number of breeding ewes you keep or buy in the following year.
The main advantage of the ewe lamb breeding system is that the generation time is reduced by one year, allowing for faster genetic progress.
This in turn leads to improved live weights, reproductive success or cross breed traits for the herd.
A successful breeding program
The success of this type of breeding program involving ewe lambs requires careful management and attention to detail.
These ewes must be carefully managed from the time they are weaned so that they reach 60-70% of their adult body weight before tupping.
To achieve this, it is important to weigh yourself regularly. This goal is required to maximize conception rates and ensure good fetal development.
However, heavy feeding of very young ewes (under five months) can reduce mammary gland development and subsequent milk yield, so is not recommended.
For example, a Texel-cross-Mule ewe lamb with a potential adult weight of 75 kg should be between 45 and 50 kg at the time of tupping.
The correct selection of rams is very important when breeding from mother ewes. Pair rams with ewe lambs that are smaller than average maturity.
Ideally, farmers should use a ram with known Estimated Breeding Values (EBV) for maternal traits such as lambing ease, along with their judgment, and use breeds with lower birth weights.
Although the supply of EBV rams in Northern Ireland is difficult due to the performance records of relatively few breeders, it is something worth considering.
The low initial reproductive capacity of lambs is due to many factors, one of which is the age of onset of puberty.
Although this can occur between 7 and 10 months of age (it can occur earlier with ram interaction), not all ewe lambs reach puberty in the selected breeding window, leading to an initial loss of potential fertility.
In addition, ewe lambs are described as “shy” breeders due to a combination of shorter, less intense estrous periods and a lower likelihood of seeking rams than mature ewes.
If using rams, leave fertile rams with ewes for 14 days before introducing them.
Studies show that rams prefer mature ewes over ewes (potentially due to the difficulty of mating).
Therefore, ewes need repeated service and separation from mature stock is required to increase conception success. The ideal group size is one ram to 25-30 ewes and graze on smaller plots or pastures.
After conception, low embryo survival has been demonstrated, with studies showing more than double the embryo losses of ewes compared to mature ewes in the first 30 days after conception (JPHanrahan).
To avoid this, for several weeks during tupping, graze at lower grass heights with poorer nutrition to slow down the amount of hormones filtered by the liver, which will hopefully result in higher screening results.
This is a delicate balance as ewes still need to gain at least 250g/day for a further six weeks after tupping to help the embryo survive and then reduce to 130-150g/day by six weeks before lambing.
Scanning and nnutrition during pregnancy
Screening should be done around day 60 of pregnancy, which then leaves enough time to either cull them or keep them for another year.
The scan result also allows for a more accurate feeding program based on litter size.
During early and mid-gestation, ewes require approximately 20% more feed than mature ewes of similar weight to ensure continued growth.
Do not overfeed in the last week before lambing and aim to feed only for maintenance and pregnancy, not for growth. Feeding to grow at this point will produce large single lambs and potentially increase lambing difficulties.
As with pregnancy, lactating ewes require approximately 20% more feed than mature ewes of similar weight to provide sufficient nutrients for lactation.
The farmer should be aware that ewes may have a higher risk of mastitis because the teat skin may not have hardened yet and is exposed to certain bacteria for the first time.
In addition, the mammary gland will still develop. First-time lambs also take longer to nurse their lambs than older ewes, therefore increasing the risk of teat and udder damage.
Another concern that farmers have to deal with breeding ewes is the thought that these ewes will never reach their full potential in later years.
Results of a study by AFBI Hillsborough showed that ewe longevity was not affected by age at first mating, with both ewe lambs and hoggets slaughtered at similar rates each year.
Furthermore, both ewe lambs and hoggets reached the same mature weight (average 65.5 kg) and thus the age at first mating did not affect the growth rate of the ewe.
Weaning should take place when their lambs are 10-12 weeks old to allow lambs to continue growing and reach their potential target weights.
The introduction of creep feeding will also help to reduce the demand and stress on the ewe and lamb.
From an environmental point of view, raising pedigree ewe lambs can provide additional benefits, for example by reducing the carbon footprint on the farm due to less productive stock being transported to obtain the same product from lamb.
When comparing this system within a commercial carbon footprint tool, the carbon footprint was 5% lower for the system using ewe lambs instead of hoggets (AHDB).
Farmers who are part of Business Development Groups (BDGs) and benchmark their businesses financially with CAFRE can now also complete the carbon benchmark.
In conclusion, for farmers who have already selected ewe lambs for breeding, there are a few points to consider:
- Ewes should be at least 60-70% of their adult weight;
- Use a mature ram known for lambing ease;
- In mating groups, one ram to 25-30 ewes;
- To increase embryo survival, stop wet grazing during the first few weeks of tupping;
- Ewe lambs need to grow 250 g per day for 6 weeks after mating;
- Wean early when offspring are no more than 12 weeks old.
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