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Hi folks,
A Midwest sheep producer called us asking about ultrasound pregnancy scanners for predicting lambing dates.
My answer....
- We jug our ewes just prior to lambing in a heated barn. 90 jugs.
- They lamb without either assistance or surveillance from 5 pm to 7 am.
- Pre-jugging saves labor (no need to haul lambs and persuade oft-reluctant ewes to follow you into a jug), mis-mothering, hypothermia and shepherd “burn-out” (no night hours)—in exchange for more ewe time in the jugs. Which means more labor to feed and bed them individually instead of as a group.
- More accurate prior knowledge of the due date would reduce time in the jugs and save labor, feed, and bedding but it’s been a challenge.
Background:
Lambing occurs Jan-May and Sept-Oct. Approximately 500 Dorper/Katahdin/Romanov “hair” ewes and 100 wool ewes. As much fall lambing as practical. Not using large terminal sires reduces the “over-sized single-lamb” dystocia risk—but also reduces optimum slaughter weight for our lambs. This works for the ethnic market.
We’ve found the accuracy of due date predictions from ultra-sound scans to be too low to be useful. We use the most experienced scanner (machine and person) in the region. For us (could be different for others), scanning is good for telling us who is not pregnant and who has more than 1 lamb but not due date predictions.
We also use our own ultrasound machine but we’re not yet set up to be efficient with it. With it we can tell who is open (90% accurate) and who has more than 1 (perhaps 60%). Neither can be 100% because we know that post-scan embryo loss occurs in most flocks—perhaps more so in prolific flocks.
We also have tried tight control of ram time with the ewes to predict lambing dates. How? By turning rams in with 150 ewes and then immediately pulling them when 50 have been marked — aiming for ram time to be less than 5 days and thus a lambing window of 11 days. We found this method to be too management intensive in our farm’s world (conflicting demand for labor) and still meant some ewes in jugs for up to 2 weeks.
So what are we doing now to condense (and thus predict) the lambing dates? Using CIDRs and a high ram/ewe ratio. Results after only four experiences? 80% lambed in 6 days. Most within 4 days. Enables us to fill all 90 jugs, lamb them from Mon-Fri and empty the jugs within a week. Repeat at whatever intervals are practical.
I welcome any comments and suggestions.
- Stan Potratz (Premier’s Founder)
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