The least desirable word to describe an on-farm experiment is ‘inconclusive’.

When we use any given product to solve an agricultural issue, the real satisfaction is derived from firing something down an animal’s throat, and then observing a near magical response and turnaround occurring within a few days.

Unfortunately, in the case of my lambs this year, all my best scientific interventions could be summarised by shrugging my shoulders, scratching my head, or simply admitting I have no clue what is going on.

I have had an issue with dirty lambs since May or June, but especially since weaning in July.

It seems important to point out that this is not connected particularly to poor thrive, since performance targets have been spot on.

I always set a goal for 80% of (March/April born) lambs to be sold fat (or retained for breeding) before the end of September. Various obstacles contribute to falling short of this aim, with the weather, nematodirus, sward quality, and coccidiosis all being used as legitimate excuses for my failings.

However, things are purring along nicely this season and, despite the irritation of working with scouring animals, the sought-after 80 figure is bang on target.

Evidence

Anecdotal evidence would suggest that other farmers are having the same bother with scour. This is a source of comfort in some ways but can distract from trying to solve the problem. In the past, I have discovered that it is easy to latch onto a common concern, then draw the conclusion that sure we’re all in the same boat and use this as an excuse to ignore the issue.

So, when dirty tails began appearing earlier in the year, I was determined to find out the underlying cause. In truth, I still have no idea.

Dung samples were taken in July, and this revealed very low levels of stomach worms, but high levels of coccidiosis. Based on my own evidence from previous sampling, I know that this may or may not affect lamb thrive, and the latest advice backs up this theory.

The vets are now telling us to treat scouring lambs, or lambs that are not putting on weight. Therefore, I used this result to begin a rough and ready experiment to see what would best dry up these wet tails.

Marked

Some lambs were dosed with Tolracol for cocci and marked with a blue head. Others were dosed with Oramec for stomach worms and marked with a green head, and the third group were injected with a few mls of pen/strep and marked with a black head. The most spectacular result was obtained from the antibiotic injection, followed by the coccidiosis drench, and lastly the worm dose, as expected.

One small injection of pen/strep translated into an overnight drying of back ends, whereas the Tolracol worked slowly (three or four days) and dried up most of them, but not all.

Then, just as I was starting to draw my conclusions after a week or two, they began to scour all over again. Or to be more accurate, some stayed dry irrespective of the product used, some began to turn wet again, and some of the untreated lambs then started scouring also. Meantime, weekly weighings saw both wet and dry tails being selected for slaughter.

Last option

At this stage, I remembered my own advice to some farming friends, which was that when all else fails, dose them with Levafas Diamond.

I have no idea why this simple product works, but in the past, this has dried them up for no logical reason I can think of.

So, out came the yellow drench and gallons of it were duly poured down their necks. Sure enough, it dried them up. But only for about ten days, then off they went again, all competing for the gold medal in the Dirty Bum Olympics.

Handling

Probably the most annoying aspect of having dirty lambs is handling them in pens and yards. I dagged and cleaned them each time they were in, but this didn’t stop the green smear from painting every lamb in the batch.

By the time they were heading back out to the field, some of them were the colour of Kermit the frog.

Guess

If I had to hazard a guess, I’d say the source of the problem is possibly linked to soft grass and a consistently low dry matter intake.

After the poor growth in June, I may have sown a bit more artificial fertiliser than usual, and sward quality has been reasonably good ever since.

It’s a fairly weak argument, but I can’t think of anything that’s any more logical. Once again, I am left wondering why lambs that have had a good start in life can’t just get on with the business of growing quickly without all the side distractions.

As I’ve been saying for decades now; maybe next year.