When we started our small flock of sheep (in 2005), we gave a great deal of thought to how we would match our production calendar to the forage cycle in the Sierra foothills where we live. While we still had much to learn 12 years ago (indeed, we still have much to learn today), we knew that we wanted to match our period of greatest forage demand with the period of greatest forage growth. For us, everything started with grass - and it still does today!
We live and operate in a Mediterranean climate in our part of the Sierra foothills. Our annual weather pattern is typified by cool, wet (hopefully) winters, and dry, warm summers. Accordingly, our annual grasses grow according to distinctive and predictable patterns. In most years, we get a germinating rain in mid-October or early November. Our annual grasses start growing - and continue to grow until the days get too short and the soil gets too cold (usually just before the winter solstice). During this winter dormant period, the grass doesn't grow much (if at all) - but usually by early February, the days are long enough (and the soil warm enough) that our grasses and forbs (broad-leaf plants) start growing slowly again. By the first of March - if we've had normal precipitation - our grass is ready to rip! In most years, we have our greatest quantity of highly nutritious annual grass from early March through mid-May.
So much for the supply side of the equation. On the demand side, our ewes require the greatest quantity of highly nutritious forage in the last third of their pregnancies and the first 6 weeks of their lactation (that is, the 6 weeks after they give birth). They require so much forage during this phase, in fact, that our stocking rate increases by almost 100 percent. In other words, 100 ewes that are about to give birth will consume nearly twice as much grass at this point in their reproductive cycles as they will when they aren't pregnant or nursing lambs.
Logically, then, we try to match supply with demand. We time our production system so that the ewes are giving birth when the annual grasses begin to grow rapidly. We start lambing in late February and finish lambing around the first of April. As a consequence, we've never fed hay during lambing - Mother Nature sees to the needs of our ewes during lambing. In addition to matching forage supply with forage demand, this decision allows us to map out the rest of our production year.
Our shearer tells us that sheep don't shear well in the first 6 weeks after lambing - so we wait to shear until the youngest lambs are 6 weeks old (usually in the first week of May). Since we want to avoid getting stickers and other vegetation in the ewes' wool, we pay attention to where the sheep are grazing before shearing.
We typically move the sheep back to our irrigated pastures in mid-April. Depending on the year, we'll wean the lambs (that is, separate them from their mothers) sometime in June. After weaning, the ewes can graze on dry forage (more about how we manage this type of grazing in a later installment). The lambs (those that we're keeping, anyway - replacement ewe lambs and feeder lambs) stay on our higher quality irrigated pasture.
In late August, we bring the ewes back to our irrigated pastures. We check their body condition, teeth and udders to make sure they can stay in the breeding flock. And on the first of September, we start flushing them. Flushing involves putting the ewes on a rising plane of nutrition prior to breeding to increase ovulation rates. We've found that proper flushing can increase our subsequent lambing percentage by 40-50 percent - that is, flushing can increasing lambing rates from 1.3 lambs per ewe to 1.8 lambs per ewe.
Since sheep have a gestation period of 145-155 days, we count backwards from our desired lambing date of February 22. That means the rams get turned in with the ewes around October 1. Since we want to concentrate our lambing season (a matter of labor efficiency), the rams come out six weeks later in mid-November. The ewes then "settle" in their pregnancies for roughly three weeks - we try not to do anything that might cause stress (like trim their feet or move them long distances).
Once the ewes have settled, we haul them back to our winter range - the landscape where they'll stay through lambing. In mid-January (4-6 weeks before lambing), we'll trim their feet and give them their vaccinations (which will transmit immunity to their lambs). Then we wait for lambing - and the cycle starts again.
Ruminant livestock - cattle, goats and sheep - have an amazing capacity to convert grass and other forages into meat, milk and fiber. Grazing lands that won't grow a cultivated crop, our sheep convert sunshine, rain, carbon and soil (in other words, grass!) into products we can use. By working with nature, we have essentially eliminated the need to provide supplemental feed (hay or grain) to our ewes. With the exception of flushing (when we do provide a bit of supplemental protein and energy), our ewes typically "harvest" everything they consume by grazing. It all starts with grass!
Look for the next installment: Lambing on Pasture