Lambs coughing

Jimbo789

I have 100 ewe lambs that were purchased in September currently grazing redstart with access to hay. They are being kept as breeding hoggets for next year. They are on the redstart 5 weeks now and around 10 days ago I noticed some of them giving an odd bit of a cough. It seems to be becoming more prevalent in the last few of days, especially so when they were moved onto a fresh section of redstart and started gorging themselves.

I got a faecal tests done in case lungworm might be the cause of the coughing.  The tests showed no lungworm or fluke but worm egg count of 700.

McMaster Technique:

700 Trichostrongyle EPG present. Few coccidial oocysts present

Sedimentation Technique:

No fluke eggs detected.

Modified Baermann Technique:

No lungworm larvae detected

Could the high worm count be causing them to cough? Do sheep generally cough more while grazing brassica crops just because of its more coarse nature?

I am going to give them a worm dose in the next few days. They were already dosed with Cydectin TriclaMox when they arrived in early September and were injected with Dectomax 6 weeks ago. As they have already had 2 group 3 clear doses would it be better to give them a group 2 yellow dose this time or are they less effective this late in the year? Would Zolvix be a better option?