The pros of breeding ewe lambs in their first year
Yesterday saw 353 ewes and ewe lambs bred using laproscopic AI at Lyons. Sponges were pulled from two batches on Saturday morning with a three-hour time difference between the two groups.
Ewes and ewe lambs received 500 international units of PMSG (Pregnant Mare Serum Gonadotrophin) to increase ovulation rate, at sponge removal.
Another 75 ewe lambs were bred using natural service and rams went in with these ewe lambs 36 hours after sponge withdrawal. The rams will stay in for about three days and then will be turned out again to pick up repeats 14 days after the initial mating.
We are targeting a scanned litter size of 1.8-1.9 within the mature ewe flock. We lamb the ewe lambs alongside the main flock and we think this is a crucial aspect of successfully managing the ewe lamb flock. Many people would lamb ewe lambs after the main flock, and while this has some advantages in terms of increasing the weight of the ewe lamb at mating, it does extend the lambing season. Ewe lambs tend to cause more issues at lambing and the farmer's appetite and enthusiasm for lambing has often waned by the time the ewe lambs begin to lamb down.
The mature ewes had an average weight of 74kg at mating and the ewe lambs averaged 48kg (this was a diverse group of ewe lambs). This puts the ewe lambs at approximately 65pc of their mature live weight.
It's important to have ewe lambs at a minimum of 60pc of their mature weight at mating, the heavier the lamb the better the performance.
Recent data from both Teagasc and Britain shows the merits, financial and otherwise, of breeding ewe lambs in their first year.
Despite this, ewe lambs continue to make only a modest contribution to the Irish national flock.
However, the situation is not unique to Ireland and a very similar situation exists in New Zealand. Farmers are hesitant to breed ewe lambs, and it must be said that if the animal and the system are not managed correctly, then significant problems can be encountered.
If ewe lambs are too light at mating, feeding lambs for catch-up growth after mating risks these ewe lambs producing lambs of low birth weight, with reduced vigour, reduced reserves of brown fat (the main energy reserve in the newborn lamb) and consequently increased risk or mortality.
Moderate bodyweight gain is required in the ewe lamb throughout pregnancy.
Breeding ewe lambs below the target weight can reduce subsequent milk production, and hence lamb performance and result in a situation where the ewe lamb does not recover sufficient condition at her second mating, reducing her litter size as a two-year-old.
Another very important aspect of ewe lamb management is feeding them correctly in late pregnancy and I will continue to report on our nutritional programme for this group as pregnancy progresses.
Sixty eight lambs were sold two weeks ago and they yielded a carcass value of €95 per head.
This is very marginally up on the same time last year. At the moment, there are 90 store lambs remaining on the farm and concentrates were introduced to this group last week.
Grass growth rate is remaining reasonably strong with growth rates of 30kg DM/ha/day recorded. The forage rape is progressing well and we recently purchased four Gallagher Smart Fence systems to aid with the grazing management of this crop and general grassland management.
We've received the silage test results and they look reasonably good. Dry matter is 31pc, pH 4.1, crude protein (CP) 15.1pc, dry matter digestibility (DMD) 75pc, metabolisable energy (ME) 11.5 MJ and UFL 0.84.
Now is the time to get your silage tested as it will allow plenty of time to make decisions regarding your winter feeding programme.
Conditions this year were much improved on last year for conserving fodder, but we still need to know the feeding value of what's in the pit or bale.
What we must avoid is over-estimating the contribution made by forages to nutrient supply and underfeeding the ewe in late pregnancy as it will compromise the lambs for the remainder of the year.
Dr Tommy Boland is a lecturer in sheep production and ruminant nutrition at UCD's research farm at Lyons, Newcastle, Co Dublin
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