The magnitude and duration of such effects are species and life-cycle specific. I've been doing just that for 4 years thus far with no problems.
My dogs never gave me a problem squirting this into their mouth, but dripping it onto a small piece of dog biscuit and giving them that is probably easier. I also treat periodically with Safe-guard goat dewormer when I see any evidence of roundworms. Dictyocaulus viviparus Cattle Grubs parasitic stages: Transitory discomfort has been observed in some cattle following subcutaneous administration. Note that you should always round the dosage up, not down. Try to look at it as you are wasting money, rather than an accusation that you're risking your dogs' health.
I have great experience with giving tiny doses from treating our hens. I never thought of that. But even if your dog has been taking the Heartguard and getting the much smaller recommended dosage, if you suddenly switch to giving them x because you don't want to dilute the ivermectin down to the usual dosage, if they're one of the sensitive types, it could kill them.
Below is a link to a semi-technical article on the topic.
Mild and transient pain reactions may be seen in some swine following subcutaneous administration. In fact, a fair number of rescues are using the "slow-kill method" in dogs that are light HW positive. The dosage is much higher than that used for heartworm prevention, so it's important to have an accurate diagnosis prior to treatment, especially for demodex.
Ivermectin is derived from the avermectins, a family of potent, broad-spectrum antiparasitic agents isolated from fermentation of Streptomyces avermitilis. See my Contact page for more information. The math for his table seems to be off, but except for the smallest dogs, within the safe range.
However simple heartworm preventive treatment using ONLY the smallest recommended effective dosage is safe and easy for non-herding dogs or dogs with no collie blood or dogs who have been tested and don't have the gene that makes them susceptible to the ivermectin as long as you stick within the established guidelines, which are clearly stated in the OP. IVOMEC Injection is indicated for the effective treatment and control of the following harmful species of gastrointestinal roundworms, lungworms, grubs, sucking lice, and mange mites in cattle:.
It can really be dangerous. Clean, properly disinfected needles should be used to reduce the potential for injection site infections.
According to what I have done in the past, my dose for her would be 1.
IVOMEC 1% Injection for Cattle and Swine
Grade A Ultra 24 Milk Replacer, 8 lb 1, Inspiration for dinner time under the stars. Thanks for all your help and the reading has been educational. Maybe I missed it, but I don't see how often to give this formula to your dogs. This product is not labeled for use in alpacas, goats or llamas, therefore there are no dosage directions for use in these animals. It has not hurt them at all.