What age ought to substitute ewes be first mated at?

Whereas lambing substitute ewes at one-year-old is a standard follow in lots of flocks, some farmers desire to first lamb replacements at two years-of-age.
With good husbandry and diet, the Faculty of Agriculture, Meals and Rural Enterprise (CAFRE) has mentioned lambing ewe lambs can enhance the monetary viability of sheep methods and scale back the variety of breeding females stored, or purchased in, the next 12 months.
Stephen Flanagan, a senior beef and sheep advisor at CAFRE has outlined that breeding from ewe lambs permits for quicker genetic progress, optimising dwell weights, reproductive success, and crossbreed trait advantages.
Breeding weights
The success of such a breeding programme involving ewe lambs requires cautious weight administration and a focus to element.
Ewe lambs must have reached 60-70% of their mature body weight previous to mating, a goal that Flanagan mentioned is crucial to maximise conception charges and guarantee good foetal growth.
E.g., breeding from a Texel X Mule ewe lamb with a possible mature weight of 75kg should be between 45-50kg at time of mating.
Nonetheless, the CAFRE senior beef and sheep advisor mentioned that heavy feeding of very younger feminine sheep (youthful than 5 months-of-age) can scale back mammary gland growth and subsequent milk yield.
Ewe lambs can have a decrease preliminary reproductive efficiency which could be attributable to numerous components, together with the age of the onset of puberty.
Whereas this could happen between 7–10 months-of-age, it may be introduced on earlier with the interplay of teaser rams.
If utilizing teaser rams, the teaser needs to be left in with the ewe lambs for 14 days earlier than fertile rams are launched.
CAFRE recommends that ewe lambs ought to mate with ram breeds with a smaller than common mature measurement and farmers ought to use breeds with proof of decrease delivery weights.
The perfect group measurement, in keeping with CAFRE, is one ram to 25-30 ewe lambs and grazed in small fields or paddocks.
Publish-conception
CAFRE referred to research that confirmed decrease embryo survival has been demonstrated in ewe lambs when in comparison with mature ewes within the first 30 days following conception.
To assist counteract this, CAFRE recommends that ewe lambs ought to mate on decrease grass heights of poorer diet.
This will help decelerate the quantity of hormones filtered out by the liver which in return will hopefully lead to larger scanning outcomes, in keeping with CAFRE.
Nonetheless, whereas ewe lambs are really useful to be on decrease grass high quality, Flanagan mentioned they should be gaining a minimum of 250g/day for an extra six weeks post-mating, after which lowered to 130-150g/day up till six weeks earlier than lambing to help in embryonic survival.
Being pregnant
Throughout early and mid-pregnancy, Flanagan mentioned ewe lambs want about 20% extra feed than mature ewes of an identical weight to maintain their persevering with growth.
He urged farmers to not overfeed within the final week earlier than lambing and goal feed just for upkeep and being pregnant, not progress.
Feeding for progress at this level, in keeping with the CAFRE advisor, will create massive single lambs and doubtlessly improve lambing difficulties.
From an environmental facet, breeding ewes as ewe lambs can even present extra advantages, e.g., by lowering the farm carbon footprint.
When utilizing these outcomes inside a business carbon footprinting software, CAFRE mentioned the carbon footprint was 5% decrease for a system utilizing ewe lambs reasonably than hoggets.