safeguard is a waste of time and money. try valbazen or Synanthic. I really like synanthic, but the initial cost of a bottle is pricey. Of course having the goats die is pricey too.
I would be surprised if you also are not dealing with coccidiosis, this needs to be treated for at least 5 days. in drinking water or by hand orally. WE use corid, there are other choices, but that is what our vet recommends and we have been using it for years.
Pretty much what it boils down to is you need to improve your parasite management and get more aggressive with it. The fact that you are not loosing older stock is great, Means they have good worm resistance. Because safeguard is not that affective. Know if you gave it at like 5 x the dosage for 3 to 5 days in a row then it might help a little, But by the time you use that much it would be cheaper and easier to buy another wormer.
Use valbazen at 1 cc per 20 lbs, although I have heard of people using it at the rate of 1cc per 10 lbs, repeat every 10 days for 3 times.
use synanthic at the recommended dosage on the bottle, can go a little stronger. For most wormers you should over estimate the dosage, except Prohibit.
Can NOT use valbazen on pregnant animals, IT WILL abort them!!!
Our worming schedule and kid management this year.
We kid in winter time as much as possible to avoid summer parasite loads with our young kids and to not have nursing mom's have to deal with summer parasite loads.
Normally start kidding first week of February(live in Virginia), When the oldest kids are 3 weeks old we put corid in the drinking water for 5 days, at 4 weeks old we worm the kids with a white wormer(synanthic) and weigh the kids and give their first CD&T shot.
All our kids are weighed at birth, so we can now calculate daily gain, Mom's are looked at and wormed accordingly based on their appearance and if the kids seem to be growing well enough. Slow growing kids can be a sign that mom is not milking well due to a worm load problem. Not always the case, but it is something to consider.
21 to 28 days after last treatment day of the corid we run the corid again in the water, we continue this in all pasture/pens where there are any goats under 2 years of age, even if there are older goats in with them.
We feed a medicated feed with Rumensin in it as well,and set up a creep feed area for the kids. they often start munching creepfeed by 2 to 3 weeks of age and are eating a lot of feed by 5 to 6 weeks of age. Since we can have a range of age by about 4 to 6 weeks, we just deal with this the best we can by keeping plenty of creepfeed out for everyone, so the younger ones can much when the older ones are done eating.
at 8 to 9 weeks, making sure the youngest kids are at least 8 weeks, we band wethers, give the 2nd CD&T shot, give the first CL shot, worm again, weigh again and wean the kids. We keep the kids in groups with no more than 3 weeks age difference in the group, so one group could be weaned and another group could be just getting their first CD&T shot. Mom's are weaned up to pasture and grass hay.
We do not worm the entire farm on a regular basis, but the younger animals are watched closely for weight gain issues and rough hair coat, ect.... If it is a dryer spring and summer we can go longer with out worming and treating for coccidiosis, more rain like we have had this year and we have not missed a 3 to 4 week cycle of putting corid in the water and we have wormed more this year that past years.
Hope that helps.
Good luck, I hope it gets better for you all.