Thursday, March 28, 2024

FROM THE RIDGE: Keeping a close eye on recidivist sheep

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The huhu beetle, as you no doubt know, gets on its back and can’t right itself. As a boy I would rescue them and quietly position them onto my two sisters’ pillows.
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The only other species I deal with that get on their backs and can’t sort it out are my sheep.

For the first half of my career checking for cast sheep wasn’t such a big deal because they were an occasional occurrence, a minor irritation.

But for the last 15 to 20 years at this time of year, heading into and during lambing, their prevalence dictates my days.

Why the difference I hear you ask?

I didn’t used to feed my in-lamb ewes very well in an attempt to reduce bearings. Then, when they started to get a bit of sleepy and milk feverish, I’d open them up and the metabolic diseases stopped and the bearings would appear.

One evening over dinner I sat next to Peter Gluckman of the Liggins Institute and we had a very interesting discussion about feeding levels of pregnant females, the impacts of poor feeding and epigenetics.

I resolved to feed my in-lamb ewes properly and see what happened. This flock scans well over 200% including triplets so should be fed well anyway.

Four to five weeks out from due date their residual drymatter never got below 1200kg/ha DM. Almost ad lib feeding.

There were no metabolic diseases and, surprisingly, no extra bearings, fewer if anything. It made me wonder if the sudden change in feeding levels is a trigger.

I see from my records that in recent years I’ve averaged just seven bearing deaths from 1400 ewes or 0.5%. And it’s reducing. Presumably, any vulnerable ones are given every opportunity. I have barely any sleepy or milk fever ewes now, either.

Improved lamb birth weights and decent udder development are also great benefits.

But in life, you never get something for nothing. 

They can eat a surprisingly large amount of feed in that month so it needs to be well planned and on hand in the first place. And cast sheep. Lots of cast sheep.

I often muse whether sheep feel regret over their own actions.

Our farm has a bit of flat but is mostly easy rolling so those of you on steep hill country won’t have this problem.

I’m forced to check all in lamb ewes twice a day for two to three weeks before and throughout lambing. To make it easier, I keep them in big mobs until they start lambing then quickly spread them out to reduce mismothering.

And I have to shed after two weeks to quickly reduce lambing paddocks and sheep that need checking.

I can get 10-12 cast a day at peak. Because they are eating so much, they will quickly gas up and being unable to belch will suffocate if I don’t roll them over.

However, when I do roll them over at current prices, I reckon it’s the easiest $500 I’ll ever make being the $200 ewe and two $150 lambs. A high proportion of cast ewes have triplets on board.

Some seasons they can die quickly after being cast and I’m not sure why this is, possibly the type of feed. But usually they hang on until I go to the rescue.

When I do get a dead one I hold a court of inquiry and an inquest and determine if I should have been out of bed quicker or checked that farm before the other one. Such an unnecessary death.

Four years ago I started to record any stud ewes that got cast and decided I wouldn’t use any of their progeny as stud rams. I have no idea if it’s a heritable trait or even a personality fault but am now starting to see some interesting patterns.

Most ewes don’t get cast at all and quite a few of those that do get cast only once.

But there are a bunch of repeat offenders and if I wasn’t being so diligent they would be quickly removed from the gene pool. These repeat offenders can often do it again the following year.

Let us consider the plight of 466/16, pictured. I moved the stud ewes into the last paddock of the rotation so it had a lot of grass even for my liking. It had rained during the night and the sun was out that morning so a perfect storm for cast ewes right on the drop.

Three hours later I put a mob of bulls in with the ewes to help knock down the feed and checked for the inevitable cast ewes. Four were on their backs and one of them was 466/16. Her second time cast this lambing so far and once last year.

There’s an older ewe that gets cast several times each year.

All these ewes are chock full of twins and triplets but, as I said, most of them don’t get cast at all.

It might be the shape, inclination to have a scratch, an unknown factor or probably a combination of factors that cause casting.

I’m now going to boot these miscreants out of the stud.

You never know, one day we might get sheep that don’t die from anything at lambing time.

But then it would be too easy.

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