Contested science makes dubious policy: challenging the BVA and RSPCA on non-stun slaughter [UPDATED]

In recent weeks, I have written a number of posts setting out why I think the SDP should rethink its current policy of wanting to ban non-stun slaughter, “as requested by the British Veterinary Association and RSPCA”. I have argued that, as a communitarian party committed to religious tolerance, the SDP should think very carefully about a policy that – whatever the intentions – would have negative effects on the Jewish and Muslim communities. In this piece, I aim to do something different – to show that the request of the BVA and RSPCA is based on contested science, and so can be abandoned for that reason alone. 

What the request of the BVA and RSPCA was previously based on

The BVA and RSPCA issued a joint statement on non-stun slaughter, along with the Humane Slaughter Association (“HSA”). I will refer to it as “the Earlier Joint Statement”. It was previously available on the BVA’s website, here. (Update: As of January 2020, it is no longer available at that link. It can still be accessed via the RSPCA’s website, at, archived here.  In case it is also removed from the RSPCA website, I have preserved a copy at BVA-RSPCA-and-HSA-statement-on-welfare-at-slaughter and have also made a screenshot below.)

RSPCA & BVA joint paper

The first line of the Earlier Joint Statement says:

Scientific evidence demonstrates that slaughter without pre-stunning compromises animal welfare. 

A footnote listed just four examples of such evidence – four papers published in volume 57 (2) of the New Zealand Veterinary Journal in 2009. NZVJ

The first one, “an introductory review”, is presumably an overview of the other three, all of which are co-authored by TJ Gibson and various others. I refer to them below as “the Gibson articles”. (The abstracts are available here, here, here and here. You can access the full articles if you are prepared to pay a lot of money!)

Since the Gibson articles were published in 2009, however, they have been robustly challenged by two prominent scholars in the field: Professor Joe Regenstein and Dr Temple Grandin.

The first challenge: Professor Joe Regenstein (2012)

Joe Regenstein is Professor of Food Science at Cornell University. In 2012, he wrote an article titled The Politics of Religious Slaughter— How Science Can be Misused”. On page 4, he has strong words to say about the Gibson articles (emphasis added):

The recent papers by Gibson et al. (2009 a,b,c,d) are an example of such a questionable piece of work. These papers have many serious limitations. A list of some of those concerns will be presented. Dr. Grandin has put a disclaimer on her web site criticizing this work. Yet these papers are being used politically in Europe as the “proof” that religious slaughter is inhumane!

The knife used was rather short—only 10 inches and the actual slaughter and the “pen” are poorly described. The special equipment used to restrain the animals is not shown. What about details about the actual cut – how many strokes and where on the neck? The head holder may also permit too much movement? The training of the slaughterman is not given. Like so many papers, they do not give enough details to evaluate the religious slaughter (or un-stunned slaughter as they call it). Only in the discussion is religious slaughter discussed without establishing whether the work itself is actually relevant.

The sham cut is actually more like a negative control, i.e., what happens with minimal pressure. No information is provided on the impact of a lot of pressure with no cutting on some of the parameters measured. And who sharpens a knife with a knife sharpener?

Why is the heart rate so high for the first paper and much lower in two of the other papers? it suggests that some animals were more stressed? This is often observed for the convulsions after slaughter regardless of method. It also seems that the normal “sticking” of the animal after non-penetrating stunning was never done and would be another important control.

They actually admit in one of the papers that the halothane treatment might have had an effect on some of the results!

The papers are sloppabout how the words unconsciousness, insensibility, and undoubted insensibility are used. And the papers also seem to reference a lot of the bad religious slaughter for the times they quote for time to insensibility, and is it insensibility or unconsciousness? Isn’t the later more critical? Words like suffering and psychological shock are used without definition or justification. And a lot of “wishy-washy” words, like “probably, likely, possibly” are used in the papers, yet the authors are publicly supporting a strong anti-religious slaughter position.

The second challenge: Dr Temple Grandin (2017)

Dr Temple Grandin is Professor of Animal Sciences at Colorado State University. She has written extensively on religious slaughter. In a 2017 piece, she argues that the study upon which the Gibson articles were based, was flawed:

A study done in New Zealand in 2009 shows that slaughter without stunning causes pain. A new EEG (brainwave) method was used, which can determine when an animal is feeling pain. In these experiments, lightly anesthetized calves were cut with a very sharp knife that was 24.5 cm long. The weight of the calves was 109 to 170 kg. One reason why the calves were lightly anesthetized was to prevent animal movements (movement artifact) from changing and distorting the EEG patterns. The experiments showed that the calves would have been experiencing pain during the cut (Gibson et al, 2009 ab).

The knife used in this experiment was much shorter than the special long knives that are used in Kosher slaughter. The use of a shorter knife may possibly have had an effect on the painfulness of the cut. The author has observed that shorter knives, where the tip of the knife gouges into the wound during the cut, will cause struggling. An animal may also struggle when the wound closes back over the knife during the cut. Since the calves were anesthetized, it was impossible to observe behavioral reaction during the cut. From reading the methods sections in the papers, it was not possible to determine if the wound was held open during the cut, which may help reduce pain. The knife used in this experiment was similar to many of the knives the author has observed being used for halal slaughter. The special long knife used in kosher slaughter is important. When the knife is used correctly on adult cattle, there was little or no behavioral reaction (Grandin, 1992, 1994). Barnett et al (2007) reported similar reactions in chickens. Only four chickens out of 100 had a behavioral reaction. Grandin (1994) reported that the behavioral reaction of cattle was greater when a hand was waved in their faces compared to well done Kosher slaughter. All of the cattle were extensively raised animals with a large flight zone. They were all held in an upright position in a restraint box. The results of this study clearly show that the use of a knife with a 24.5 cm long blade definitely causes pain. Another factor that may have had an effect on pain was the use of a grinding wheel to sharpen the knife instead of a whet stone. There is a need to repeat this experiment with a Kosher knife and a skilled shochet who obeys all the Kosher rules for correct cutting.

Summary and implications

It should go without saying that policy should be informed by a proper evidence base – particularly a policy as sensitive as this one, given its serious implications for the Jewish and Muslim communities. However, Joe Regenstein and Temple Grandin trenchantly challenge the evidence put forward by the BVA and RSPCA (and HSA) in the Earlier Joint Statement. It follows that the Earlier Joint Statement is, at best, an uncertain basis with which to support a call for a ban on non-stun slaughter. This alone is a reason to think again – quite aside from any considerations about religious liberty. As I have argued elsewhere, it is surely preferable simply to require all meat products should be clearly labelled as to the means of slaughter, thus enabling the consumer to make an informed choice.

A note on chronology

The four “Gibson articles” cited by the BVA and RSPCA were all written in 2009.

Joe Regenstein’s critique was written in 2012.

It is unclear when the Earlier Joint Statement referred to above, was first written, as it is undated. However, according to this source (“Food Justice in US and Global Contexts: Bringing Theory and Practice Together”, eds. Ian Werkheiser, Zachary Piso, Springer, July 2017, p. 298), it appears to have been written no later than June 2016:


This was four years after Joe Regenstein’s critique. Yet the Earlier Joint Statement only cites the 2009 articles, and not the 2012 critique.

There can be only three possible explanations for this. The BVA and RSPCA (and HSA) may have written the Earlier Joint Statement after 2009, but before 2012, and neglected to update it after the publication of Regenstein’s critique. This would suggest sloppiness on their part. Alternatively, they may have written it after 2012, but without being aware of Regenstein’s critique. This would suggest poor research on their part. Or, finally, they may indeed have been aware of Regenstein’s critique, but suppressed it as it clearly undermined their own position. This would suggest a lack of integrity on their part. Only the BVA and RSPCA themselves know which of these explanations is correct. 

Update (4 January 2020)

The BVA and RSPCA (and HSA) Earlier Joint Statement is no longer on the BVA’s website. Have they been reading my tweets? (It is still available on the RSPCA’s website.) The BVA retain a page on the topic on their website, where they claim that “evidence on slaughter without pre-stunning, known as non-stun slaughter”, has various adverse effects on animals, but they do not actually cite any such evidence! A policy position is also available, in which the BVA say “Our view is that all animals should be stunned before slaughter”, but again fail to cite any evidence to support this view. A BVA & RSPCA joint letter to the Secretary of State for Environment, Food and Rural Affairs, likewise refers to “scientific evidence” but again fails to cite any! This, surely, is an inadequate basis on which to support the change in the law which those organisations seek.



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6 Responses to Contested science makes dubious policy: challenging the BVA and RSPCA on non-stun slaughter [UPDATED]

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