Is cloning horses ethical?
M. L. H. Campbell
Department of Production and Population Health, The Royal Veterinary College, North Mymms, Herts, UK.
Corresponding author email: email@example.com
Keywords: horse; equine cloning; welfare; ethics; equine assisted reproduction
This paper assesses whether cloning horses is ethical by
reviewing ethical arguments against cloning of nonequine
species and determining whether they apply to horses,
analysing ethical arguments about horse cloning which do
not apply to noncompetitive species and considering the
ethical dilemmas faced by veterinarians involved in horse
cloning. The author concludes that concerns about the health
and welfare of cloned horses render the technique ethically
problematic and that the onus is on those providing
commercial equine cloning services to collate data and
provide a stronger evidence base for ethical decision-
Somatic cell nuclear transfer (SCNT) or ‘cloning’ is currently
being offered as a commercial method of horse reproduction
in countries including the European Union, the United States,
Australia, New Zealand and South America (Hinrichs 2005,
2006; Herrera 2015; Hinrichs and Choi 2015). In 2012, it was
estimated that there were 100–200 cloned horses worldwide
(Hinrichs 2012). It is likely that the number of cloned horses
being born per year is small. Herrera (2015) reported that 20
viable cloned foals had been produced over 4 years in South
America, whilst Reis (2015) estimated that 2–5 cloned foals
per year are born in Europe.
Cloning is not allowed by international studbooks
registering racing Thoroughbreds. The American Quarter
Horse Association is another notable example of a studbook
which refuses to register clones (http://www.latimes.com/
which will register clones include the majority of Warmblood
stud books and the World Breeding Federation for Sport
Horses. It is probable that cloning has been used in horses
of various breeds being used for the disciplines regulated
by the Federation Equestrian Internationale (FEI), although
the FEI does not have data on which horses competing
under FEI Regulations are clones (G. Akerstrom, personal
Reasons why owners choose to clone horses include the
production from a competitively successful castrated male
animal of an entire male clone which can be used for
breeding, the attempted ‘recreation’ of a favourite animal
and attempted duplication of a successful competition
Cloning of any species of animal is ethically contentious
(Nolen 2007). In 2012 the FEI changed its rules to allow clones
and offspring of clones to compete. However, the European
Commission in December 2013 tabled proposals to ban the
use of the cloning technique in the EU for farm animals and
the import of such animal clones (IP/13/1269 18/12/2013). The
proposals of the European Commission included horses used
for agricultural production purposes, but allowed derogations
for ‘...animals kept and reproduced exclusively for other
purposes such as research, the production of medicinal
products and medical devices, the preservation of rare
breeds or endangered species, sporting and cultural events’,
which effectively excluded horses used for purposes other
than agricultural production from the proposed ban on
cloning. In October 2015, the European Parliament amended
the European Commission’s proposal, to remove the
derogation from the ban for sporting and cultural events
(Amendment 30: http://www.europarl.europa.eu/sides/
0285). This means that should the European Parliament’s
amendments be agreed in regulation negotiations with the
European Council, cloning of all horses except those of
endangered breeds for which no other method of
reproduction can be used will be banned in the EU.
However, cloning of horses for all purposes will continue to be
allowed in many other countries.
Against this rather incoherent legislative background, the
aim of this article is to determine whether there are
convincing ethical arguments for banning cloning of horses. It
ﬁrst reviews general ethical arguments against the cloning of
animals of all species and analyses whether they apply to
horses. Are arguments against cloning of other species
convincing? If so, should they apply to horses, or is there
something different about cloning horses which could make
cloning horses ethical even if cloning other animals is not so?
Secondly, the article considers whether there are any ethical
arguments against cloning which apply to horses but not to
other species, for example, arguments about sporting ethics.
Finally, ethical dilemmas which might face veterinarians who
are asked by their clients to become involved in equine
cloning are presented.
Food safety concerns
In parts of Europe, although not commonly in the UK, horses
are eaten. The initial debate within the European Union
about cloning of farm animals incorporated concern about
the possible health effects on man of eating cloned animals
and their products. Were these concerns justiﬁed and do they
apply to horses?
There is undoubtedly public concern about the health
implications of consuming clones or their products (Anon
2008a,b, Aizaki et al. 2011). Scientiﬁc evidence suggests that
such concerns are unfounded (Anon 2008b, 2009a, 2010,
2012a). Although this evidence relates to ruminants rather
than to horses, it is hard to see why health risks in man
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1EQUINE VETERINARY EDUCATION
Equine vet. Educ. (2016) () -
should be associated with eating cloned horsemeat when
there are none associated with eating cloned meat derived
from other species. The European Commission has indicated
that a ban on cloning food-producing animals is not justiﬁed
on food safety grounds (Anon 2012a) and there is no
evidence that this does not apply to horses as well as
In the USA, Argentina and Brazil, unlabelled cloned
animals and their products are now allowed in the food
chain and can be exported (Anon 2012b). Cloned meat is
primarily beef, but no data is available on the consumption
of cloned horsemeat. Some consumers feel that it is unethical
to clone animals even if eating cloned produce is safe (see
below). Cloned meat entering the food chain unlabelled
does therefore raise an ethical issue about transparency,
relating to consumers’ rights to know what they are eating.
This would apply equally to horsemeat or other types of meat
being produced by cloning.
Is cloning animals simply morally wrong?
There is undeniably something fundamentally different about
cloning compared with all other assisted reproductive
techniques (ARTs), since cloning aims to reproduce an
existing animal, whereas all other ARTs aim to produce a
novel animal. The idea that there is something fundamentally
wrong with cloning, that it is somehow beyond the realms of
moral acceptability, pervades the literature on cloning in
man (Shapiro 1996; Petersen 2002) and is often expressed as
‘an affront to human dignity’. Such concerns are voiced
even in institutional documents (Harris 1997) such as the
Oviedo Convention for the Protection of Human Rights and
Dignity of the Human Being with regard to the Application of
Biology and Medicine (Harris 1997) and the Report of the
President’s Council on Bioethics: Human Cloning and Human
Dignity (2002). These concerns quite probably do reﬂect
public sentiment, but are poorly deﬁned (Harris 1997;
Savulescu 2005; Simpson 2007).
Interestingly, there is a similarly poorly deﬁned public
repugnance with the concept of cloning animals, which
might be characterised as an ‘affront to the animal’s dignity’.
Thus one investigation into public attitudes to animal cloning
(Gjerris et al. 2006) found that ‘moral assessment is the most
important factor behind the level of support’; that people
were concerned about ‘violation of the integrity of animals
that cloning might constitute’ and that ‘cloning, seems to
cross an invisible border between the natural and the
unnatural’. In the 2008 Eurobarometer survey (Anon 2008a,b),
61% of respondents thought that animal cloning was ‘morally
wrong’ and 38% said that animal cloning was unethical on
moral grounds, whatever the potential beneﬁts in medical or
food production terms.
Such moral objections to cloning would apply equally to
all food-producing animals, including horses. Yet these moral
objections are no better deﬁned for animals than they are for
man. Most ARTs violate nature, yet the public seem only
really to object to cloning: embryo transfer; artiﬁcial
insemination and IVF do not inspire a similarly visceral
response. Gjerris et al. (2006) suggests that this is because
‘although the concept of naturalness leaves many questions
to be answered, it is (undoubtedly) contradicted by the
asexual character of reproduction by cloning’. Certainly,
although asexual reproduction does occur in nature, asexual
reproduction of farm animals at least (for which the most
data on public opinion exists) does not.
Whilst public unease about animal cloning based on ill-
deﬁned notions of ‘dignity’ undeniably exists, such unease is
not necessarily a strong ethical reason to ban cloning, either
of horses or of any other species. ‘
..moral gut responses may
be morally admirable but they may also be morally wrong’
(Anon 2009b). Whilst the concept of (inviolable) human
dignity pervades religion, medicine and law, there is no proof
that animals themselves have any concept of ‘dignity’.
might consider that there is nothing digniﬁed about an
animal kept under an intensive farming system being used for
medical research, or being carried in Paris Hilton’s handbag,
but an ‘affront to dignity’ seems a weak ethical reason for
objecting to any of these practices, all of which can
legitimately be objected to for other stronger reasons relating
to failure to meet an animal’s welfare needs.
Cloning for conservation
The draft legislation to ban cloning of farm animals proposed
by the European Commission in 2013 and amended by the
European Parliament in 2015 includes exceptions for the
conservation of rare breeds and endangered species. Where
animal numbers are small and animals are wild or semi-feral,
making the application of invasive ARTs difﬁcult, cloning may
provide a method of preserving rare genetic material and
promoting biodiversity (Anon 2009c; Yang et al. 2010). Might
cloning of horses to preserve rare breeds, for example in the
face of an outbreak of fatal exotic disease, such as African
horse sickness, be ethically justiﬁable even if cloning for other,
competitive or sentimental purposes was considered
The welfare costs of cloning are discussed in the next
section. These costs to individual animals are independent of
the reason(s) for undertaking cloning. Any ethical justiﬁcation
for allowing cloning to facilitate conservation would therefore
have to be based in a cost:beneﬁt argument that any costs
to individual animals are outweighed by a perceived beneﬁt
of preserving the species. Yet is there an absolute beneﬁtin
species preservation? Is biodiversity necessarily a good thing?
Is the loss of some species (or in the case of horses, breeds)
not simply a normal Darwinian mechanism?
The consequences of cloning to increase or preserve
biodiversity could themselves have ethical implications;
cloning a woolly mammoth, for example, is now feasible, but
the consequences in terms of impact on the environment,
habitat, other animals and on the welfare of the animal itself
(reintroduced to an environment so different from the one
which its species last inhabited) are unknown. Whilst it may
seem a subjective shame to lose some of the equine rare
breeds, the argument that they perform an environmental
function which no other breed can do is tenuous. Indeed the
environmental function of some rare breeds, such as the
Suffolk Punch, has decreased signiﬁcantly with the
mechanisation of agriculture. Even the management of
moorlands, to which the rare breed of Exmoor ponies, for
example, make a signiﬁcant contribution, can nowadays be
undertaken by other methods. Thus, although governments
may face legal obligations under the United Nations
Animals’ needs to express normal behaviours (an interest
which should be respected) might be analogous to ‘dignity’
© 2016 The Authors Equine Veterinary Education published by John Wiley & Sons Ltd on behalf of British Equine Veterinary Association
2 Cloning horses
Convention on Biological Diversity (1992) to promote
biodiversity, the ethical imperative to do so by subjugating
the welfare of individual animals to the desire to preserve an
equine breed is unconvincing.
Are there welfare-based reasons which make
animal cloning unethical?
Current cloning techniques result in recognised welfare
problems (Renard et al. 2001; Houdebine et al. 2008; Anon
2012b; Kim et al. 2012, 2014). Problems associated with
cloning across a variety species, but particularly cattle,
include placental abnormalities during pregnancy, fetal
abnormalities, dystocia related to ‘large offspring syndrome’
in farm animals, neonatal weakness/disease, systemic illness/
disease in cloned animals and premature ageing of adult
clones (Kuhholzer-Cabot and Brem 2002; Chavatte-Palmer
et al. 2003; Loi et al. 2006; Arnold et al. 2008; Houdebine
et al. 2008; Jang et al. 2010; Anon 2012b).
One of the prime factors behind the European
Commission’s decision in late 2013 to propose a ban on the
cloning of food animals (http://europa.eu/rapid/press-
release_IP-13-1269_en.htm. Accessed 20.03.14) and the
recent European Parliament decision to extend that ban
(Anon 2015) is the fact that farm animal cloning is viewed as
a risk to animal welfare (Gamborg et al. 2005). This was
made clear by Renate Sommer, German MEP, who stated
that the prohibition was based in concerns about ‘the
negative effects on animal welfare’ and that ‘ prohibiting
cloning is a matter of European values and principles’ (Anon
2015). If concerns about the health and welfare of clones
and their dams provide a convincing ethical argument
against cloning of farm animals, does the same argument
apply to horses?
Data about the health and welfare of equine clones is
comparatively lacking. Only the groups led by Katrin Hinrichs
in the USA (Hinrichs 2006; Johnson et al. 2010) and Cesare
Galli in Italy (Galli et al. 2003; Lagutina et al. 2005) have
published data on their success rates and on problems
associated with current cloning techniques. These data are
reviewed in the next few paragraphs.
Embryo loss in equine cloning
Hinrich’s group (Johnson et al. 2010) reported that 26% of
cloned embryos transferred by them resulted in the birth of a
live foal, whereas Galli and coworkers reported that three live
foals resulted from transfers of more than 100 cloned embryos
(Galli et al. 2003; Lagutina et al. 2005). In a retrospective
study of all nuclear transfer derived embryos at Texas A&M
University from 2004 to 2007, Johnson et al. (2010) found that
81% of oocytes which had been subjected to nuclear transfer
cleaved after activation. Of those cleaved embryos, 5%
developed to blastocyst stage. A total of 51% of those
blastocysts, having been transferred, resulted in the
establishment of pregnancy in the recipient mare, as
determined by ultrasonography at 11–16 days post ovulation.
The only data available on fetal losses and abnormalities
comes from Hinrich’s group (Johnson et al. 2010). A total of
six pregnancies were lost between 3 and 9 months of
gestation and one recipient mare developed a neurological
condition and was subjected to euthanasia. The cause of the
neurological condition was not discovered and her fetus was
normal. A total of three fetuses were aborted between 5 and
9 months; one had no abnormalities, one had no detectable
abnormalities (it had been scavenged) and one had an
umbilical hernia (omphalocoele). One foal was born
prematurely and died.
Data about dystocias in horses is also sparse. Johnson et al.
(2010) reported that one mare had a dystocia which
required caesarean section at full-term and a dead foal with
severe contraction of the forelimbs and an omphalocoele
was delivered. A total of 14 of 31 mares which were pregnant
between 11 and 16 days post ovulation delivered live foals
and 13 were born at normal gestational length. None was
oversized or overweight in comparison to the mare and all
mares had uncomplicated foalings. One had a prolonged
gestation, but was nonetheless born small and underweight;
however, at a year of age, its weight was comparable to
that of the other surviving foals.
In the study of Johnson et al. (2010), two foals had signs of
hypoxic ischaemic encephalopathy at birth, but recovered
with treatment. Two foals died shortly after birth, one from
pneumonia and one following anaesthetic complications
during an attempt to surgically correct a perceived bladder
abnormality. A total of 7 of 14 foals required administration of
supplementary oxygen for >12 h after birth, one for 15 days.
All foals were treated as ‘high risk’ and given antibiotics after
birth. A total of 8 of 14 foals required antibiotics for more than
5 days. Half of the foals had some form of umbilical
abnormality, 8/14 had some form of ﬂexural or angular limb
deformity (all corrected by 6 months) and 2/14 exhibited
incomplete ossiﬁcation of the cuboidal bones. On average,
foals required 8.5 days of intensive care following birth. Those
which survived a week grew and developed normally
thereafter, apart from one foal which required two surgeries
to remove uroliths (bladder stones). Of the three foals
produced by Galli and coworkers (Galli et al. 2003; Lagutina
et al. 2005), one died from septicaemia and the other two
were reported as being healthy.
It is clear that the evidence base about health and
welfare issues associated with cloning using SCNT is much less
robust for horses than for farm animal species. The broad
summary from the little data available seems to be that
equine cloning is associated with high rates of embryonic
loss; some incidence of fetal abnormalities (although this
appears to be lower than that recorded in farm animals) and
a requirement for neonatal intensive care. In contrast to farm
animals, dystocia attributable to oversized fetal clones does
not seem to be a signiﬁcant problem in horses. Similarly, the
problems of hydrops of the fetal membranes which occur in
cloned cattle seem not to occur in mares, possibly due to
differences in placentation. It is difﬁcult to know whether
some abnormalities in neonatal and foal clones, for example
limb deformities, are truly attributable to the cloning process,
because such problems are not uncommon in foals anyway.
To date, there have been no long-term studies on the health
and welfare of cloned horses.
Further research is clearly needed to increase the
evidence base on the short, medium and long-term health
and welfare effects of equine cloning. Until such evidence is
© 2016 The Authors Equine Veterinary Education published by John Wiley & Sons Ltd on behalf of British Equine Veterinary Association
M. L. H. Campbell 3
available, one could argue that, following the precautionary
principle, cloning horses is unethical on welfare grounds,
since it seems that there are more problems associated with
embryos, fetuses and foals created using SCNT than there are
with foals conceived using other equine ARTs.
The caveat to this ethical argument is that many of the
problems associated with cloning (in all species) are probably
related to technique, particularly in vitro culture conditions
(van Wagtendonk-de Leeuw et al. 2000). Interestingly, culture
conditions which cause large offspring syndrome and
abnormal clone phenotype in ruminants, seem not to have
the same effects when used for nonruminant embryos (Hill
2014). No data is currently available about any possible
correlation between SCNT techniques and particular
problems in horses, but it seems reasonable to expect that in
horses, as in other species, problems are likely to diminish as
techniques improve (Hinrichs and Choi 2015). Paradoxically,
techniques will not improve unless cloning continues. This is an
argument if equine cloning is to continue to be allowed for
those clinics undertaking equine cloning to undertake
anonymised and collated reporting on the health and welfare
of equine clones at all stages of their lives. Given the small
numbers involved, such reporting could operate on a
voluntary basis in the equine sector, with due attention to
client conﬁdentiality and commercial sensitivities. In order to
acquire data about medium and long-term effects, owner
cooperation would be required. Collated reporting would
increase the evidence base about health and welfare issues
experienced by equine clones and, importantly, any
correlation between technique and such problems. Such
evidence would simultaneously make it much easier to judge
whether on welfare grounds equine cloning is or is not
currently ethical and provide an evidence base for improving
technique so as to minimise negative effects in future.
Cloning and sporting ethics
Consideration should be given as to whether there are any
additional ethical arguments which might apply to cloning
horses but not to cloning other species. One argument
around the ethics of cloning which applies to horses and
racing dogs, but not to farm animals species, concerns
sporting ethics. Although cloned horses have been allowed
to compete freely in some disciplines, such as polo, the FEI
initially prohibited cloned horses from competing, on the
grounds that (i) identifying clones by DNA testing would be
problematic, and (ii) cloning conferred a competitive
advantage, which violated the spirit of fair play.
There is no convincing argument that cloning is unethical
based around identiﬁcation. Despite concerns that some
sports horses are not DNA tested and that the FEI’s ban on
cloning was therefore unenforceable (http://
internationalanimallaw.com/node/784, accessed 08.01.2016)
the vast majority of equine studbooks now use DNA analysis
to identify and register horses and would thus be capable of
identifying clones and registering them as such. Given that
clones do not normally look physically identical to the donor
animal or to each other, and that microchipping of horses is
commonplace (in some countries, a legal requirement),
distinguishing between a cloned and a donor animal or
between two clones with identical DNA should not be
Concerns that cloning confers an unfair competitive
advantage are, at the least, unproven. In the one report on
racing cloned animals against their noncloned peers, the
cloned animals’ performance was mediocre (http://www.
thehorse. com/arti cle s/165 52/cl on ed-mul es -race- int o-h ist ory).
The FEI does not record clones competing under its rules and
does not have data on the competitive success of clones
compared with nonclones (G. Akerstrom, personal
communication). However, to date, there has been no
media coverage reporting that cloned horses have won
important FEI events.
There is no convincing evidence that equine cloning is
unethical because of reasons relating to sporting ethics. This is
consistent with the fact that the FEI reversed its ban on clones
competing in 2012.
Ethical issues facing veterinarians undertaking
Finally, this article considers the ethical dilemmas which might
face veterinarians whose clients ask them to become
involved in equine cloning. Cloning is a very specialised
technique, performed in a small number of centres
worldwide. The involvement of most veterinarians is therefore
likely to be limited to taking a skin biopsy from a donor
animal, to provide the nuclear material necessary for the
SCNT process and possibly to providing neonatal and later
healthcare for cloned offspring.
All ARTs are ethically unusual in that, unlike most
veterinary procedures, they are usually undertaken with no
expectation of improving the health or welfare of the animal
on which they are performed. In this respect, cloning is no
different from commonly used equine ARTs such as artiﬁcial
insemination and embryo transfer. Depending on the AR
technique, the health and welfare of up to three animals (a
donor animal, a recipient animal who gestates and gives
birth to the foal and the foal itself) should be considered.
In terms of the direct effects on the donor animal, there is
nothing inherently ethically different about a veterinarian
subjecting a donor animal to a skin biopsy for SCNT than
there is about a veterinarian subjecting a donor animal to
another ART such as embryo retrieval; both are mildly
stressful/painful procedures for which analgesia and sedation
can be provided (Campbell and Sandoe 2015), which are
not expected to offer any direct beneﬁt to the donor animal.
As discussed above, however, cloning is associated with risks
to the health and welfare of cloned foals. Such risks have not
been proven in foals created by other equine ARTs
(Campbell and Sandoe 2015). The risks to foals produced by
cloning may provide veterinarians involved in undertaking
skin biopsies for SCNT with grounds for questioning the ethical
justiﬁcation of being involved in such procedures, albeit that
the direct negative welfare effects on the donor animal on
which the skin biopsy is being performed are mild and can
Arguments about unfair sporting advantage are
unconvincing grounds for considering equine cloning
unethical. There is no evidence that eating either cloned
horsemeat or cloned meat from other animals poses a public
health risk. However, all cloned meat ought to be clearly
4 Cloning horses
labelled to enable consumers to select against it on moral
grounds. For some people, cloning horses and other species is
unethical because cloning goes beyond the limits of how far
man ought to interfere with nature and is therefore simply
morally repugnant. Such arguments are hard to refute,
because they are a matter of moral conscience. However,
the concept of ‘an affront to dignity’, which forms part of
some moral objections to cloning, seems a weak ethical
reason for branding cloning ethical.
Concerns about the health and welfare of recipient
animals gestating and giving birth to clones and about the
short, medium and long-term health and welfare of cloned
farm animals provide compelling reasons to consider cloning
unethical on cost:beneﬁt grounds. What little evidence exists
so far suggests that some welfare problems which are
prominent in the cloning of farm animals, particularly fetal
oversize and dystocia, do not occur with such signiﬁcance in
horses. However, other reported problems, particularly those
occurring in equine neonates and foals, render use of the
technique ethically dubious. The onus is on all those providing
commercial equine cloning services to provide a stronger
evidence base for ethical decision making about equine
cloning by collating data about the short, medium and long-
term health of cloned horses. This will require collaboration
not only between specialist centres, but also with
veterinarians who are not specialists in cloning, but who
provide healthcare for cloned offspring throughout their lives.
Author’s declaration of interests
No conﬂicts of interest have been declared.
Ethical animal research
This paper has been assessed according to the Royal
Veterinary College’s Code of Good Research Practice
(authorisation No 01144).
Source of funding
The author undertook the research for this article whilst
funded by the Wellcome Trust as a Biomedical Ethics
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6 Cloning horses