Hendrik Hansen, [11 Jun 2022 at 11:46:12]: I have lately used Hyalase in rhinos and made a significant difference in knockdown effect. I used Hyalase or DMSO in giraffe and if you need quick knockdown it is definitely a good one to add Can anybody comment on how hyalase work and dosages. I see a benefit in downtime with much lower dosages that was previously suggested. I remain unsure mainly because I do not use it a lot ?? Richard Burroughs: The theory is that it breaks down intercellular bonds that allows better permeation and absorption of drugs from injection site, with 30 % improvement in down times. Henry Labuschagne, [11 Jun 2022 at 12:12:48]: The active ingredient of Hyalase is hyaluronidase. It increases the permeability of connective tissue through the hydrolysis of hyaluronic acid by splitting the glucosamidic bond between C1 of the glucosamine moiety and C4 of glucuronic acid. This leads to increased absorption of injected drugs. I use a minimum of 1000 iu in antelope. In large antelope minimum 1500 iu. In pachyderms 2500 iu Richard Burroughs: Dose variable 1000 up to 5000 iu in megaherbivores Henry Labuschagne, [11 Jun 2022 at 12:15:55]: I agree with Richard that downtime improves by 20 to 30 %. I also find it useful in absorbing drugs from badly placed darts. Richard Burroughs: As it is an enzyme, it must be kept in cool box or on cold packs. It is available as a freeze-dried powder. Gets denatured easily at room temperature, and becomes less effective and virtually ineffective at those temperatures. In practical terms, it means that you need to use it asap once reconstituted with water. Peter Rogers, [11 Jun 2022 at 15:16:51]: I use 5000 iu for rhino and elephant - even keep the sterile water and azaperone in the cooler box with the Hyalase. I make up dart immediately before darting - a well placed dart makes a white rhino stand in 3-4 minutes and black rhino “stopped” by something solid at about 4 minutes as well Hendrik Hansen, [11 Jun 2022 at 16:36:51]: If it is a local effect is it dose dependant or volume dependant or probably combination of both. It seems that DMSO does the same then? Obviously another method of action but same effect? Henry Labuschagne, [11 Jun 2022 at 17:11:12]: DMSO causes vasodilation with resultant quicker absorption of drugs . Different mechanism but also enhances absorption. Q: what will be the effect of Hyalase plus DMSO ? Richard Burroughs: Good question. DMSO was largely historically used in obtaining a solution of fentanyl powder. It is no longer used for that with new formulations. An issue was safety of this solution, in that transcutaneous absorption of fentanyl is possible. David Gerber, [12 Jun 2022 at 13:31:52]: Hendrik and others that do large numbers If you have a reasonable large number of equal animals that we can dart on the same farm at the same time, take accurate down times and split them randomly in 4 groups - standard drugs - standard drugs plus hyaluronidase - standard drugs plus DMSO - standard drugs plush hyaluronidase & DMSO Silke Pfitzer, [12 Jun 2022 at 14:30:24]: If u mix DMSO with potent opioids, it means that opioid can get absorbed through intact skin… just putting this out there. David Gerber, [12 Jun 2022 at 15:26:53]: When we had the fentanyl I put some fentanyl in DMSO on my skin and left it for 30 seconds, then washed it off. I felt absolutely nothing. If we use DMSO we must be careful, but we have to be careful in any case and I don't think the risk is huge, as long as we take good precautions Richard Burroughs: There is an MMedVet project that was done on Hyalase, and published. Will look for it and post Henry Labuschagne, [12 Jun 2022 at 16:46:40]: I think we need to do a comparative study as David suggested : 4 subgroups from the same large group of animals on the same farm kept under the same circumstances etc to keep all variables to a minimum. Richard Burroughs: Mark Dittberner did this as a double blind study at Wildlife Pharmaceuticals Research bomas, where all animals were subject to the same processes. He used low doses of etorphine + Hyalase, and a standard dose of etorphine (old regime) with Hyalase. He found a 30 % reduction in down time compared to the control (no Hyalase ) and a reduction in times with the low etorphine dose also. Publication: The study was done on blue wildebeest, and probably needs to be done on other bovids as well. I am not aware of any other work. What would be interesting to see is the effect that hyalase has on the low opioid regime of HH. The doses that were used then as low etorphine doses are higher than the current HH regime Henry Labuschagne, [12 Jun 2022 at 18:09:02]: Yes, but I would expect a 30 % reduction in down time even with HH regime. HO Reuter, [12 Jun 2022 at 21:02:04]: My gut feeling from having used Hyalase (1000-1500IU) in some HH regimes from helicopter (e.g. nyala, oryx, sable, roan and esp. kudu is a better downtime, but no detailed records, and done on different farms and scenarios. Problem for me is that with HH (esp. on the ground / boma darting,) I (all of us) generally aim for lowest effective dose to get animals down = longer downtime but good safe anaesthesia. From chopper I have tried slightly higher HH doses, Hyalase plus ketamine, to get animals down quicker, but some then too 'flat' for my liking, especially if recovery is long. In some cases I have just gone back to high opioid/ tranquiliser / ketamine /Hyalase regimes, or same low dose HH as on ground darting with longer downtime, but then stable good anaesthesia. I very much support a more comparative study then random trials of different regimes in small no‘s and not proper monitoring or recording. Ideally with blood gas analyses, etc.? Unfortunately these days I seldom dart more than 10 animals per species per farm, thus only limited experience and a non science based gut feeling. I personally have never had the urge to mix potent opioids and DMSO, in spite of being careful. Have been satisfied enough with Hyalase effect at lower risk, I guess. Rob Jackson, [19 Jun 2022 at 19:12:09]: We did more than a 100 wild zebra, from a vehicle some years ago, Hyalase definitely reduced downtime, I think by about 25 percent. It was part of a research project so I have the data but it was never published.