Now, before you start yelling at me: I am sure you were quite happy with the twitch in that emergency you had with your horse once. It might be necessary as an ABSOLUTE last resort. I’m just pretty sure most people don’t know that you’re supposed to look for alternatives before you head for that last resort. Let’s be honest, people seem to just twitch for anything the horse might resist, without even thinking they might be able to train. Clipping, mane pulling (yes, just substitute one pain for another), shoeing, mane plaiting…
When it comes to twitching horses, it seems little is known, a lot of assumed and common sense is ignored altogether. The most probable theory is that the pressure on one of the most sensitive parts of the horse causes the horse to release endorphins.
Endorphins get released in numerous situations. Exercise, sex, eating spicey food, eating comfort food, eating ginseng, love, having a laugh, sunbathing, smiling, sudden rushes of adrenaline and -oh!- severe pain. Now, unless you feed curry to your horse right before using a twitch, I’d say pain is what causes the release of endorphins. Not right away, mind you! It takes several moments for the numbness to kick in. Think of stubbing your pinky toe. It has to hurt before the painkillers start working. “The twitch is believed to work through the mediation of beta-endorphins, but there is little doubt that it works because it involves pain (webster 1994). The heart rate of horses when twitched undergoes a transient increase (Morris, 1988) before returning to baseline values. ”
We asked a pain expert what she thought. Here is what she said:
“My thoughts are that subjecting an animal to targeted acute pain will promote the release of a bunch of chemicals/ neurotransmitters. This would be very distracting as it is so aversive, and the animal would protectively immobilise itself in order to avoid more intense pain/ damage (a bit like an animal in a trap). Theoretically these pain chemicals could spread through the body & affect the “pain gate” & would help reduce pain in other areas of the body.”
Most studies seemed to measure the stress the horse was experiencing by looking for stress indicators on the outside , but a study with donkeys and another study with several stallions and geldings (horses) revealed cortisol levels were increasing (more than endorphins!). The animal is in a state of behavioural suppression.
Head shyness and fleeing reactions to seeing a twitch a second time also indicate a negative association with the tool. Stereotypies also release endorphins, so should we just keep horses locked up in solitary, barren environment? It helps reduce suffering but there must be suffering to start with. Animals (and humans) develop tolerance to opiods including morphine, so need increasingly high doses to have an effect. And horses with stereotypies tend to release endorphins by performing the behaviours.. and twitches are less effective with them. So we can tentatively conclude that horses develop tolerance to their own endogenous opiods, needing more in order to get the same effect… so over time, a twitch will become less effective if used regularly. It is also often advised to not use twitches for longer than 12-15 minutes since, in many cases, the effectiveness of the twitch tends to wane after this period, possibly because of neurotransmitter depletion at the level of synapses in the opioid pathways. In addition, there are reports of horses suddenly striking with their forelegs during twitching.
Sources on twitching
-The effectiveness of the twitch in donkeys
– Responses of cortisol and prolactin to sexual excitement and stress in stallions and geldings.
– Preliminary studies on the use of plasma β-endorphin in horses as an indicator of stress and pain
– Equitation Science – Paul McGreevy,Andrew McLean *
– The Encyclopedia of Applied Animal Behaviour and Welfare
– The Horse: With a Treatise on Draught (1831)
* Fed up Fred does not support, promote or endorse Equitation Science training techniques
Sources on pain