Origin and History
If you have been around puppies, you might have heard about Early Neurological Stimulation (ENS). ENS is a technique that supposedly generates more resilient and resistant puppies, which is why this technique is particularly popular among breeders.
Here I explore what the actual science behind ENS is and what the scientific community has to say about it. You might be surprised, so stay until the end, especially, if you have used or plan to use ENS on puppies.
ENS stems from the so-called “Bio Sensor” program (1968-1976) which was developed by the US military to produce “superior” dogs to accompany soldiers in the Vietnam war.
Although there are no public records of this program, Battaglia (2009) reviews this method and reports 5 out of 6 puppy stimulation exercises used. The 5 exercises detailed below are performed once per day from day 3 onwards, for 2-3 weeks.
- Tactile stimulation of paws with a Q-tip for 3-5 sec.
- Head held erect for 3-5 sec.
- Head pointed down for 3-5 sec.
- Supine position: Holding the pup with its belly upwards for 3-5 sec.
- Thermal stimulation: Place pup on a cooled towel (prior refrigerated for 5 min) for 3-5 sec.
In his review, Battaglia argues in favor of the ENS method and how this protocol enhances cardiovascular and adrenal gland function as well as stress and disease resistance (Battaglia, 2009). However, he does not provide any quantitative evidence for these claims.
Moreover, in his argumentation in favor of stimulation, he cites a variety of studies that have different research objectives and therefore experimental approaches: e.g. (1) stimulation in deprivation studies, (2) stimulation with mild stressors under “normal” conditions, or (3) stimulation as enrichment.
From a scientific point of view, his argumentation is flawed because the context and type of stimulation are key to the outcome. Battaglia is comparing apples and pears, just so to pass the argument for ENS which is misleading.
At this point, the lack of sufficient data does not allow for an informed opinion on ENS.
Other studies investigate the effects of ENS
Given the strong claims about the effectiveness of ENS, it is not surprising that Battaglia’s review sparked interest within the scientific community.
To date, three more studies have investigated the effects of Battaglia’s ENS protocol (Boone et al. 2023; Gazit, Terkel, and Goldblatt 2022; Schoon and Berntsen 2011).
In the study of Schoon and Berntsen (2011), ENS was applied to puppies who would become mine detection dogs.
The researchers found no difference in puppies treated with ENS to the control group (more than 80 dogs in total). The lack of effect was explained by the already very rich basic socialization program that is in place for all puppies (including the control group). This means that if there was an effect of ENS, it was probably too mild to be seen if puppies where socialized.
In the study of Gazit et al. (2022), ENS was tested on puppies raised to become military working dogs (more than 70 dogs in total).
The authors describe indeed an effect in ENS treated puppies: they have higher motivation in odor search and more biting drive. However, this difference only appeared after 10-12 months of age. This long period makes it difficult to attribute the effect to ENS (which is performed for the first three weeks only).
And indeed, the authors themselves argue that handlers were not blind to the ENS condition (they knew which dogs belonged to the test group and which ones to the control) which likely resulted in more attention and thus, over time, increased socialization within the ENS test group (a phenomenon called the Pygmalion effect: since I believe in you, you actually perform better).
The fact that the effect was seen so late, strongly suggests that later handling was more decisive for the dogs’ performance than the ENS protocol performed just after birth. Therefore, here again, the scientific data does not really support the effect of ENS as it is claimed by Battaglia.
Lastly, Boone et al. (2023) quantified the effects of the ENS protocol on puppy welfare in commercial breeding kennels.
Clear signs of distress originating from the environment in a commercial kennel (such as transportation, ear cropping, etc.) on all puppies could be measured. However, no differences were found between the ENS and control group (more than 75 dogs in total).
This last study is quite informative because it shows that even in a reduced, stressful environment like a commercial kennel, ENS does not seem to be beneficial for puppies.
Conclusion
Given the current scientific data, it is not possible to confirm the benefits of ENS on puppy welfare, whether puppies were raised within a context of rich socialization or in a rather minimal environment of a commercial breeding kennel.
As Gazit et al. (2022) also points out very well: one should be suspicious about claims that a one-minute daily manipulation like ENS, can have a long-lasting impact on dog behavior that goes beyond the one achieved by merely holding the pup in your hand for the same amount of time.
Pet professionals like breeders and trainers, should be cautious about the use of methods that present themselves as scientific, but fail to fulfill scientific criteria.
Therefore, it is crucial to perform rigorous literature search or seek out an expert opinion before implementing new methods to their practice.
Most importantly, ENS cannot replace best practices in early handling, enrichment and socialization provided by the caregivers which have been proven to have an overwhelmingly positive effect on puppy welfare.
Bibliography
Battaglia, Carmen L. 2009. “Periods of Early Development and the Effects of Stimulation and Social Experiences in the Canine.” Journal of Veterinary Behavior 4(5):203–10. doi: 10.1016/j.jveb.2009.03.003.
Boone, Grace, Aynsley C. Romaniuk, Shanis Barnard, Traci Shreyer, and Candace Croney. 2023. “The Effect of Early Neurological Stimulation on Puppy Welfare in Commercial Breeding Kennels.” Animals 13(1):71. doi: 10.3390/ani13010071.
Gazit, Irit, Joseph Terkel, and Allen Goldblatt. 2022. “Are There Long-Term Effects of Early Neurological Stimulation (ENS) on Working Dogs?” Applied Animal Behaviour Science 249:105588. doi: 10.1016/j.applanim.2022.105588.
Schoon, Adee, and Terje Groth Berntsen. 2011. “Evaluating the Effect of Early Neurological Stimulation on the Development and Training of Mine Detection Dogs.” Journal of Veterinary Behavior 6(2):150–57. doi: 10.1016/j.jveb.2010.09.017.
