Aseasonal sheep like most hairsheep can get into lamb at any time of the year. They are much less responsive to day-lengths, unlike merinos who start cycling better and more frequently when the day-lengths are decreasing (Feb-Apr in the southern hemisphere).
In intensive systems like we are growing into, many can produce lambs three times in two years - ie once every 8 months. It is well known that 3 in 2 years doesn't always work because of lower weaned numbers as a percentage at each lambing, and depending on the time of year, extra feed costs can outweigh the advantage of producing more lambs per year.
There is also the STAR system that has five periods in a year that ewes lamb into, and uses 21 day joining periods. It averages that the ewes lamb every 7 and abit months.
These intensive programs only work if there is good quality and bountiful feed all year round. Ideally those on the equator, like Kenya, could very successfully use these systems.
However, where we farm, winters are short days and low intensity of sunlight and it is cold and wet. Summers are long days, intense sunlight, but hot and usually lacking rainfall. The danger period for new lambs is late May to late July - winter storms. If we used a STAR or 3 lambings in 2 years system, some lambing periods will be in the depths of winter, and some will be in the peak summer period, neither of which is good for the lambs or ewes.
What we are trying to achieve on Caluka is to drop lambs in late March to late April, and late August to late September. The reason for this is that we usually have two springs per year. Our average break to the season is March and well fertilised pasture in autumn will provide spring like growth. The weather is usually calm and sunny, a great time for lambs to be born and then be fat enough to get through the winter storms.
And of course dropping lambs at the beginning of spring (August) will utilise the spring growth for all the new lambs and keep the ewes in good condition to be able to join the rams again in November. A percentage of the March/April born ewe lambs will also be ready to join the rams in November (6-7 months of age).
To get into that system of ewes lambing twice within 12 months, we have had to squeeze a few timings closer this year. Our ewes that have been lambing were due to end yesterday (the 9th May 2022). We have put our rams back in with the ewes yesterday on the 9th May. This is so we can get the next batch of lambs to start dropping on 1st October 2022 and by 2023, we hope to have the timings in place to lamb in late March to end of April, and late August to end of September each year.
It will be interesting to see what percentage of ewes can do this - ie lambing twice in 12 months. Any dry ewes only have to wait half a year to be with the rams again, but eventually when we receive our target number of ewes, those dry ewes will be sent to a new home. Bit by bit we will be finding the genetics that suit our intensive system. There are breeds that have no problems lambing every 6-7 months. It is only considered not normal because of our merino history in this country, and because it has only been tried by a few in the high rainfall areas of Australia. The genetics exist where ewes can lamb every 6-7 months.
We will probably have a little field day for those interested later this year, but keep watching these blogs to see how our progress goes. These are fascinating days we are in.