During breeding season, the ram of each breeding group wears a harness with a large crayon fastened right over his brisket (chest). Whenever the ram mounts one of his ewes, the crayon tends to leave a colored marking on the ewe’s dock (just above the tail), letting us know that she has been bred. We make daily rounds of the breeding groups — sometimes twice each day — to record any new markings. Once I have the marking dates for all of the ewes, I sit down and calculate due dates: 148 days from marking for the Romneys and 150 days for the Romeldales.
We also ultrasound our ewes during their second trimester — usually in early December — to find out whether the ewe is bred or open, how many lambs she carries, and the number of gestational days that have already passed. The ultrasound technician bases the gestational age on the current size of the fetuses and an average lamb birth weight of 8 lbs. For those farms that have average birth weights closer to 6 lbs, her estimate of gestational length will be too long; and for birth weights like ours — closer to 11 lbs — her estimate will be short. Once we have the data from the scan, I convert gestational age to due dates and add them to my calendar.
The problem is that the tech’s due dates and mine almost never agree. Not only are our lambs generally much bigger than what she considers a “standard lamb birth weight,” but she is also giving an estimate based on fetal size, whereas I have an actual marking date from the act of breeding. Despite my dates being generally more accurate, there is value in the ultrasound dates. They can confirm a breeding date or, when I have doubts (which sometimes happens with multiple markings), can let me know which of several dates was the actual breeding date.
This year something unusual happened. For the vast majority of our ewes, the ultrasound technician hit the exact gestational age of the fetuses she scanned, confirming my due date from the crayon markings. I can only assume that she must have gotten complaints about her 8-lb birth weight setting and adjusted it upwards — but I don’t know. When it came time to compile my list, I was massively confused. I wasn’t sure what to do with her due dates since I was used to them being off by a couple of weeks. But now for nearly every ewe, she had hit my date within a day or so.
I went through my list of due dates, and if there were two marking dates, I let the ultrasound information confirm which was the actual date. If I had a date that was within two weeks of the ultrasound data and that was the last date the ewe was marked, I used that date. I compiled my list and waited for lambing.
Just before lambing began, I put my list of bred ewes up on the whiteboard in the barn, more or less in the order they would deliver, listing the due date for each ewe. To ensure they delivered inside the barn, I locked in each group of ewes several days before they were due. The older ewes know our process and are often eager to begin — moving first from the general population of bred ewes to the drop pen, then with their lambs to a jug (individual pen) after delivery, after a few days to a mixing pen, and then back into the general population of ewes who have delivered their lambs.
January, my bottle baby from 2010, is a big ewe. She has been around awhile and knows how it all works. She always scans with twins — yet has for years now always given us triplets. It has been kind of a running joke with the ultrasound technician — until this year when January surprised me and scanned with triplets. What is that supposed to mean? That the ultrasound technician finally found that elusive triplet ? Or that January is actually carrying quads this year? I have no idea, but I now consider her high risk.
Even more confusing is the fact that I had a marking date for her of October 11, giving me a due date of March 9th — last Wednesday. For two weeks before that, January had been trying to get into the drop pen. She obviously knew that once in the drop pen, she was almost done with her gestation — and I don’t think she understands that she doesn’t go in until she’s ready. Instead, she thinks that she becomes ready because I let her in. For weeks, as I moved ewe after ewe into the drop pen, January stood there, ready to volunteer. She wanted it to be her turn — she wanted to be done, so very badly! Week after week, I turned her away and yet watched as she got bigger. Finally on Friday, March 4th, I let her into the drop pen — and she was thrilled.
January’s due date on March 9th came and went, and she has continued to get bigger. She can hardly stand anymore because she is so wide, yet she continues to widen. I rechecked my dates and realized that, unlike the accuracy of the other ultrasounds, January’s fetal gestational age at ultrasound puts her due on March 24th — way past her marking due date of the 9th. I am so confused! I don’t know what the heck to make of this situation with January. And so we wait.
Please check Friday’s blog to (hopefully) hear the end of the story!