First, we moved our sheep to McCormack Sheep and Grain in Rio Vista for our breeding season. We didn't want to turn the rams in prior to hauling our ewes to their new home, so our breeding season started about a week later than normal (which meant lambing was also a week later than normal). The dry conditions last fall (both in Auburn and in Rio Vista) meant that we were feeding hay during breeding rather than running the ewes on old irrigated pasture and newly germinated dryland pasture. We are now seeing that the combination of stressors on our ewes during breeding translated to fewer lambs this spring. Our lambing percentage is running 10-15 percent lower than normal.
With the extended dry period in Northern California from early December through the end of January, we found that we were continuing to feed hay to our sheep after we pulled the rams out of the flock. The lack of grass in Rio Vista (for our sheep, but more importantly, for the McCormack sheep) meant that we needed to move our sheep off of McCormack Ranch (to reduce the forage demand). In late January, we sold approximately 20 ewe lambs and unthrifty older ewes. In mid February, we hauled all of our ewes back to Auburn to graze pastures that had been rested for 2 years. I was a bit nervous about hauling our sheep so close to lambing, but we didn't experience any ill effects. The sheep were happy to be grazing again, too!
While we had a few early lambs (we exposed the ewes owned by our daughters to the rams earlier than the rest of the flock) we started lambing in earnest around March 1. We use a teaser (or vasectomized) ram to synchronize the estrus cycles of our ewes prior to breeding - this concentrates the lambing period. This year, about 85 percent of the ewes were bred within the first 17 days (which means 85 percent of them delivered their lambs by March 17). Synchronization helps concentrate our labor demands during lambing. We usually have a bit higher concentration - which makes me think that shipping the ewes just prior to breeding may have had impact on synchronization, too.
For the last five years (at least), we've utilized the EZ-Care scoring system developed in Great Britain for evaluating and retaining ewes that can lamb on pasture without assistance. In this system, each ewe is evaluated on three criteria (lambing ease, mothering ability and lamb vigor). We want ewes that can lamb without assistance on pasture, that will stay with and protect all of their lambs, and that produce enough milk to raise healthy and vigorous lambs. Having to pull lambs in a pasture system can problematic. Ewes that can't count or that leave their lambs require us to hand-raise lambs (which is much more labor intensive and costly). Ewes that can't convert grass to milk efficiently raise smaller (and less profitable) lambs. We have consistently sold ewes that don't measure up in these three criteria - and we've also been diligent about not retaining the daughters of ewes that don't measure up. Each year we've used this system, lambing has become easier to manage - we've developed a ewe flock with the genetic predisposition for being good mothers.
McCormack Sheep and Grain is in the process of implementing a similar system, so I had an opportunity to contrast the genetics and behavior of our flock at lambing with a much larger group of ewes that have never been selected for mothering ability. While both groups of ewes had very few lambing problems or lamb vigor issues (I didn't keep track, but I suspect we assisted similar percentages of ewes with delivering their lambs), I noted substantial differences in mothering ability. Most of our ewes stay with their lambs even while we're processing the lambs (which involves ear-tagging, paint-marking, docking and castrating - all at a day of age). This may be in part because our smaller flock is handled more frequently - we're moving sheep every few days, so they're more comfortable with human contact. Based on my experiences this year, however, I think consistently selecting for ewes that can perform well in the three criteria I've described is a huge labor (and lamb) saver.
One of the key management principles we try to apply to our sheep operation is to match our period of highest forage demand with the grass cycle. In our annual rangelands (that is, pastures that are not irrigated but that rely on rainfall for growth), we generally have the highest quality and greatest quantity of forage in March and early April. Our ewes experience their greatest forage demand in the month before lambing (during the last trimester of fetal development) and during the 6 weeks after lambing (while they are nursing their lambs). While our current drought has created substantial challenges in terms of forage production (we're seeing much less grass, and it seems to be maturing much earlier than normal), the relatively mild weather during lambing has been beneficial. Stormy weather, especially cold rainstorms accompanied by wind, can cause hypothermia in our lambs. We typically manage this risk by putting the flock in pastures with natural shelter (either topographic shelter or vegetation like trees or shrubs). In the nearly 5 weeks that we've been lambing this year, we've had just three storm events - and we've only lost one lamb to hypothermia. In this case, it was a lamb whose mother forgot she'd had twins. Based on the criteria described in the preceding paragraph, we'll sell this ewe after we wean her surviving lamb.
Looking ahead this year, we're planning to shear the ewes about 10 days earlier than normal. This will allow us to assess the quality of forage available and the amount of irrigated pasture we can access. If forage quality looks good, we'll leave the lambs with the ewes for another 2-3 weeks. If quality has declined, we'll consider weaning the lambs while they are home for shearing - this would be about 5 weeks earlier than normal. We'll also sort off and sell any ewes that didn't get bred or that lost lambs - which will allow us to save our limited forage resources for our more productive animals. When we do our final weaning, we'll also sell any ewes that didn't measure up in our EZ-Care system. I expect we'll go into the summer months with 10-15 percent fewer sheep than we have now. While we'll keep a few replacement ewe lambs this year, we'll save most of our summer irrigated pasture for flushing (that is, preparing the ewes for breeding by improving their nutritional intake before turning in the rams). While this means we won't be selling grass-fed lamb at our local farmers' market, I suspect it will increase our profitability by lowering costs and increasing our lambing percentage next year.
In the meantime, we're waiting for the last of the ewes to lamb - and we're enjoying watching the older lambs cavort in our pastures. Nothing says springtime (even in a dry year like this) like frolicking lambs!
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