Louis Greeff, [11 Mar 2024 at 15:44:38]: Leith and others In my experience, it is more difficult to tube animals when using the HH mix. It is as if the rumen sphincter is closed or something there is constricted. Could it be or am I just imagining it? Jacques ODell, [11 Mar 2024 at 21:34:49]: Louis, I am sure this could be true. I have never tubed a ruminant with the HH mix (My reason simply being that an animal that needs tubing is compromised and I will avoid using a potent alpha-2 in a compromised patient as far as possible), but my reason to believe so is based on the naltrexone work we did on goats a few years ago. Potent opioids like etorphine (as we used in the goats) completely inhibits rumen motility. This also relaxes the distal oesophageal sphincter. Hence our approach to keeping the head of a ruminant up during immobilisation, to avoid passive regurgitation and subsequent aspiration. This all makes the passage of a rumen/gastric tube quite easy. I thus think with the lower opioid dose used in the HH protocols, the rumen motility and sphincter may not be that severely affected. Has anyone listened to rumen contractions when using HH combinations? What I can tell you, especially in buffalo, is that when you use the conventional opioid dose, in combination with around 0.03mg/kg medetomidine, the regurgitation is profound… Hendrik Hansen, [12 Mar 2024 at 00:23:53]: Hi Jacques 0.03mg/kg medetomidine in combination with the conventional opioid dose would be for a 500 kg cow Thianil 6-7mg + medetomidine 0.03 x 500= 15mg. I have not used anything close to that high doses even in my initial trials, but I would imagine that regurgitation would be the least of your worries with that combination. What I can say with confidence is that with Thianil 0.5-0.75 mg + medetomidine 5-6 mg in a 500kg buffalo cow, the incidence of regurgitation is far less than with the conventional combinations. Louis, in a patient with an alpha2 muscle relaxant effect that is in sternal recumbency, you would want a helper to lift the head slightly off the ground with the nose still facing down to the ground, but to be in a comfortable position to swallow - then it is very easy to tube. I've dosed a few hundred rumen magnets to buffalo with this combo easily and without any problems. They swallow easily and it is quite easy to push a tube or magnet into the rumen without any regurgitation. We saw a high incidence of regurgitation with conventional opioid / xylazine combinations, but very few with medetomidine even with patients in lateral recumbency. Hendrik Hansen, [12 Mar 2024 at 00:37:32]: I tubed and dosed Prodose Orange in fairly compromised sable cows in a group that some died from wire worm related anaemia at Glacis Game Breeders. I immobilized them with Thianil 0.5 mg + medetomidine 3.5 mg and could intubate them without much effort. I dosed the Prodose Orange intra-ruminal because their swallowing reflex were minimal and dosing into the mouth with a syringe didn't provoke a swallowing reflex. None of them regurgitated during or after the intubation. I have struggled more to intubate sable using the conventional/ traditional high opioid immobilization, mainly because of the animal's struggles and movements, but once restrained, I thought it equally easy to intubate. Henry Labuschagne, [12 Mar 2024 at 06:33:59]: No azaperone in the cocktail? Hendrik Hansen, [12 Mar 2024 at 06:42:32]: Yes. Buffalo cow 30 mg azaperone, bull 40 mg azaperone and for sable, 15 and 20 mg azaperone respectively Leith Meyer, [12 Mar 2024 at 07:10:47]: Hi Louis, Jacques and Hendrik. Interesting discussion. Alpha-2 agonists seem to have a complex effect on the rumen and rumen sphincter. Lower doses might promote relaxation of rumination, while higher doses might influence contraction. When the rumen is full, then alpha-2 agonists seem to stimulate contraction of the sphincter, hence the risk of bloat developing. Ampie Viljoen, [12 Mar 2024 at 07:36:17]: Morning Leith, what do you consider lower and higher doses in this scenario? HO Reuter, [12 Mar 2024 at 08:17:03]: I have dosed quite a lot of sable and roan antelope after immobilisation with HH dosages, by (partially) reversing medetomidine with atipamezole/yohimbine (2mg atipamezole/ mg medetomidine) plus 10 mg butorphanol. I get staff to hold them and wait until they get their swallowing reflex back, then syringe dose and give naltrexone i/v or i/m. So far, I have had no complications doing this. Louis Greeff, [12 Mar 2024 at 11:21:21]: Leith, this is exactly what I am experiencing A further question. Do you think it has an influence on the oesophageal groove also? Hendrik Hansen, [12 Mar 2024 at 12:46:54]: Leith, I would consider the dosages we use in wildlife immobilization intramuscular as very low dosages ? Leith Meyer, [12 Mar 2024 at 17:56:19]: Hendrik, I be interested to hear why you say this. Jacques ODell, [12 Mar 2024 at 14:16:11]: Yes indeed. 0.03mg/kg (which is a commonly used dose for wildlife) is WAY too much when used in combination with conventional opioid doses. This is called the HKGK mix… I tried this many years ago on some buffalo and would not recommend it to anyone. The regurgitation was spectacular. Maybe it was linked to the diet, but I am sure the drugs played a decent role. I woke up the buffalo quite quickly, so did not have any mortalities. I am sure it can go pear shaped quickly. Hendrik Hansen, [12 Mar 2024 at 14:21:33]: How many buffalo regurgitated out of how many done, Jacques? Jacques ODell, [12 Mar 2024 at 15:11:11]: Only three. All three regurgitated and one was severe. Granted, small sample size but not worth the risk. Leith Meyer, [12 Mar 2024 at 17:26:49]: Hi Ampie. If I remember correctly the original work done on alpha-2 agonist’s effects on the rumen was done using xylazine. I will try to find the paper to see what the relative doses were. Hendrik Hansen, [12 Mar 2024 at 17:43:06]: Hi Leith. From what I saw, the effect of xylazine and medetomidine with regards to bloat and regurgitation is very much different. Maybe it's the less refined alpha-2 or the alpha-1 component effect of the xylazine ? Leith Meyer, [12 Mar 2024 Interesting. This may well be. I will see if I can find any papers on this.
