Human-Sheep Hybrids

Hi Readers,

I read an article today about a new breakthrough in which human-sheep hybrids have been created for the first time. This is an exciting development as it could be a potential cure for type 1 diabetes – a great example of how veterinary and medicine can work together.

This was a project done at Stanford university where scientists transplanted human stem cells into preimplantation embryos of sheep. The next step is to implant human stem cells into sheep embryos which have been genetically modified so they cannot grow a pancreas, in the hope that human DNA will fill in the missing code.

“We have already generated a mouse pancreas in rats and then transplanted those in to diabetic mouse and were able to show almost a complete cure without any immunosuppressants,” Dr Hiro Nakuachi, who is leading the research, said. He believes that organs grown in animals will be available for transplant within the next five to ten years.

These embryos were allowed to grow for a week before being implanted into a surrogate sheep. Current rules ban labs from allowing the survival of hybrids beyond 21 days, so the surrogate animal was slaughtered after three weeks.

This is the part of the article that caught my attention the most. There will always be ethical implications for example, if the human cells were to spread further than intended, these experiments to grow organs inside the animals could be impossible to approve for ethical reasons. However, I also thought this part of the experiment could be classed as unethical as well – if the sheep was healthy, should it really have been PTS? Of course, the rules must be followed and therefore does this make it ethical, after all it is to advance medical research?

I weighed up the pros and cons of this research:

Pros Cons
6,500 in the UK are on an organ transplant list, and it can take up to five years to reach the top. This research could help with the organ shortage crisis. The article reads “the first stage towards growing an unlimited supply of human organs for transplants and even providing a cure for Type 1 diabetes.” Whilst a cure for Type 1 is important, the wording ‘growing an unlimited supply’ implies we may starting ‘farming’ organs – is this ethical?
Scientists previously hoped pig/sheep organs could be used directly because they are roughly the same size as a human. However they were always rejected. This research gets round the rejection problem because it uses stem cells directly from a human patient. Robin Lovell-Badge (a British scientist most famous for his discovery, along with Peter Goodfellow, of the SRY gene on the Y-chromosome that is the determinant of sex in mammals. He is currently a Group Leader and Head of the Division of Stem Cell Biology and Developmental Genetics at the Francis Crick Institute in Central London) warned the organs may still be rejected by the body. “Even if they succeed in replacing all pancreatic cell types in the sheep with human cells, the blood vessels within the pancreas will be sheep derived,” he warned. “The organs could not be used for transplants into humans without triggering the immune system to reject them – and this would probably be a very fast rejection.”
Using sheep prove much more effective than pigs which have previously been used in similar experiments. Transplanting around 40 to 50 embryos into pig surrogates only leads to up to 14 piglets, while transferring three to four sheep embryos brings yields of up to three foetuses. Should we be slaughtering healthy animals because they carry embryos we have placed inside them? Can we justify this with just ‘for medical advancements’?

I am interested to see the results of this research and to read veterinary opinions on the topic in a few days time.



Prolapses in sheep

Hi Readers,

As we enter lambing season I wanted to explore a little more into common issues I face when working on the farm during this busy period. I chose today to look specifically at prolapses of the vagina as this is something I have had to deal with regularly without completely appreciating what I was dealing with.

What are they?

In some ewes a prolapse of the vagina is only seen as a pink, fleshy protuberance when lying down and disappears when she stands. However, in some ewes the prolapse doesn’t disappear when she stands and the delicate tissue becomes infected, swells up and can become damaged further and bleed. The ewe suffers discomfort at this stage, straining more and increasing abdominal pressure – this makes the situation worse.

As more of the vagina protrudes the pressure blocks off the urethra so the sheep cannot urinate. This leads to rupturing of the bladder. The vagina can also become so congested and damaged it may rupture allowing coils of intestine to escape resulting in peritonitis. Ewes usually die at this stage.

What causes them?

Usually occurs very close to lambing and in older ewes, where the cervix fails to open properly and allow birth of the lambs. The ewes usually have low calcium levels (hypocalcaemia) – calcium is important for maintaining muscle tone, so a lack of tone in the muscular walls of the vagina may lead to a prolapse.

Ewes carrying twins/triplets are more prone than those carrying singles as there is less room and abdominal pressure is greater.

How can you treat it?

In mild cases keeping a close eye on the animal should be sufficient and, as a lack of calcium could be involved, injecting 50ml of 20% solution of calcium borogluconate under the skin would be helpful.

Lukewarm water can be used to carefully clean a permanent prolapse containing a small about of very mild disinfectant and gently dab dry with a towel. Using cupped hands, the prolapse can be pushed back in slowly and patiently; care should be taken not to use fingertips as this could rupture the vagina and lead to peritonitis and eventually death. From experience I have then applied a harness in order to stop prolapsing occurring again before lambing.

Have any of you ever seen this during lambing? I’m interested to hear how you’ve dealt with it.



The Veterinary Book For Sheep Farmers, David C. Henderson 2010.

Cutaneous and Renal Glomerular Vasculopathy (CRGV)

Hi Readers,

Last month there was an outbreak of Alabama Rot (or CRGV) a few miles from where I live. The local vet diagnosed and confirmed this case. I decided to read up on it when a friend of mine asked if I’d heard of it as she was concerned for her dog. I decided to do a blog post on what I found.

What is CRGV?

The disease causes damage to blood vessels in the skin and kidney. It causes small blood clots to form in the vessels causing blockages and leads to damage of the tissue. In the skin, this causes ulceration. In the kidney, it causes severe kidney failure. It is unknown what causes Alabama rot – which is the most worrying bit! However, there is research being done.

Symptoms of CRGV?

Two thirds develop

  • Loss of appetite
  • Vomiting
  • Lethargic
  • Hypothermia (in later stages)

One third develop

  • Lameness

One fifth or fewer develop

  • Jaundice
  • Fever, in initial stages
  • Diarrhoea
  • Red or purple spots on the skin (caused by bleeding from broken capillary blood vessels)
  • Seizures (epileptic)
  • Blood in stools

Rarely dogs develop

  • Vomiting blood
  • Nosebleed
  • Large volume of urine
  • Excessive thirst
  • Lack of muscle coordination and other behavioural changes

If skin changes do occur and are caused by CRGV, many dogs will not develop kidney problems and will recover fully. The number of dogs affected with skin lesions and kidney failure remains low in the UK (56 confirmed cases across the UK between November 2012 and May 2015).

Is CRGV more common at this time of year?

Over the last 3 years, more CRGV cases have been seen between November – May than between June – October.

Where to avoid walking dogs to avoid Alabama rot?

This was one of the things my friend and I were discussing but after some research it appears there is no evidence to suggest any particular environment is more likely to cause CRGV. However, it is possible an environmental factor could cause Alabama rot but more evidence and research is needed to be sure.

Has anyone ever seen this disease before? I’d love to hear your thoughts.



Causes of sheep lameness

Hi Readers,

A few weeks ago I attended a seminar and one of the topics discussed included ‘causes of sheep lameness’. I thought I would list some of the causes we talked about and how farmers could treat them.


  • Caused by the bacterium Dichelobacter nodosus
  • Antibiotic spray – do all feet
  • Inject with Alamycin


  • Also caused by the bacterium Dichelobacter nodosus
  • Antibiotic spray – do all feet
  • Inject with Alamycin

CODD (Contageous Ovine Digital Dermititis)

  • The condition is caused by a spirochaete (flexible spirally twisted bacterium)
  • Antibiotic spray – do all feet
  • Inject with Alamycin


  • Can be caused by excess foot trimming
  • It can also follow severe cases of footrot that have not been treated promptly
  • Can be given pain killer – no foot trimming as this is what causes it!
  • These rarely recover


  • Caused by bacteria found in the gut and faeces of other sheep
  • Needs to be drained
  • Given antibiotics
  • Can be trimmed


  • It is not completely certain what causes shelly hoof
  • Can be trimmed

This seminar was useful to hear different people’s thoughts on things like foot trimming. Professionals no longer recommend aggressive foot trimming in the treatment of most causes of lameness as they often make the problem worse. Some farmers still foot trim, for example, before turn out after lambing as they find when hooves overgrow, mud gets trapped and keeps bacteria in contact with the hoof for longer as oppose to if their hooves were trimmed. Others argued with less hoof for protection, bacteria can cause problems faster.

What are your thoughts on foot trimming? Has anyone seen these conditions out on work experience? I am keen to hear your thoughts!



With thanks to the Park Vet Group for their seminar. I do not own any of these images.

Sheep’s ability to recognise human faces from two-dimensional images

Hi Readers,

I recently read an article which has led me to form a very strong opinion on the subject. There has recently been a study on eight sheep (Ovis aries, female Welsh Mountain) at the University of Cambridge. These sheep were being trained to recognise celebrity faces on a screen (Fiona Bruce, Jake Gyllenhaal, Barak Obama and Emma Watson). They were also tested to see if they recognised their handlers on a screen as well.

Training – Celebrities

Training involved the sheep moving around a specially-designed pen choosing the photograph of the celebrity. At one end of the pen, they would see two photographs displayed on two computer screens and would receive a reward of food if they chose the correct photograph (by breaking an infrared beam near the screen); if they chose the wrong photograph, a buzzer would sound and they would receive no reward. Over time, they learn to associate a reward with the celebrity’s photograph.

Test – Celebrities

After training, the sheep were shown two photographs – the celebrity’s face and another face. In this test, sheep correctly chose the learned celebrity face eight times out of ten.

In these initial tests, the sheep were shown the faces from the front, but to test how well they recognised them, the researchers next showed them the faces at an angle. As expected, the sheep’s performance dropped, but only by about 15% – a figure comparable to that seen when humans perform the task.

Test – Handlers

The researchers looked at whether sheep were able to recognise a handler from a photograph without pre-training. The handlers typically spent two hours a day with the sheep. When a portrait photograph of the handler was placed randomly in place of the celebrity, the sheep chose the handler’s photograph over the unfamiliar face seven out of ten times. In this test, the researchers observed an interesting behaviour. Upon seeing a photographic image of the handler for the first time (they’d not seen the photo version of this person before) the sheep did a ‘double take’. Checking first the unfamiliar face, then the handler’s image, and then unfamiliar face again before making a decision to choose the handler.

This experiment was very interesting and on reading how they made the experiment fair was very fascinating (see first article in references). However, what the researchers are now doing with the findings is something I do not agree with.

A team at the University of Cambridge have said: 

‘ “Sheep are long-lived and have brains that are similar in size and complexity to those of some monkeys. That means they can be useful models to help us understand disorders of the brain, such as Huntington’s disease, that develop over a long time and affect cognitive abilities. Our study gives us another way to monitor how these abilities change, particularly in sheep who carry the gene mutation that causes Huntington’s disease.”

Professor Morton’s team recently began studying sheep that have been genetically modified to carry the mutation that causes Huntington’s disease. ‘

Huntington’s disease

UK research carried out in 2012 found the figure for those affected by this condition to be about 12 people per 100,000. Huntington’s disease affects more than 6,700 people in the UK and is an incurable neurodegenerative disease. Together with colleagues in Australia, the team successfully bred a strain of Merino sheep carrying the human genetic mutation that causes Huntington’s disease.

Whereas I am, of course, extremely supportive of research needed for this awful disease, I do strongly believe against genetically modifying the sheep to give them the disease. Unlike animal testing where the animals are euthanized afterwards to minimise anymore suffering – a quick and humane process, from what I can gather the researchers are breeding the animals so the pain they feel due to the disease can be studied. The team could work on genetically modifying the faulty gene causing the disease in the first place rather than spreading the pain as a result of it, to another animal. Another concern I have is, the disease affects humans once they reach adulthood, if we are messing with another species’ genes how are we to know if effects will be the same? Will they suffer longer or less than humans? When will the sheep start showing symptoms? When looking into this study I have found no mention of ethical concerns – I, myself, am concerned for how the researchers will minimise the negative effect on the animals health.

What do you all think? Is the GM of sheep for the purpose of medical research justifiable?

I would love to hear all your thoughts.



Johne’s disease

Hi Readers,

A couple of years ago I was lucky enough to hear Peter Orpin speak about Johne’s disease in a cattle vet-farmer meeting. I thought this week it would be a good idea to revisit the disease and its causes.

Cause of Johne’s

M. paratuberculosis bacteria embeds itself in the wall of the ileum (lower part of the small intestine). As an immune response, infected tissues attempt to regenerate healthy tissue which leads to visible thickening of the intestines. This prevents nutrient absorption, resulting in weight loss.

Late in the infection, antibodies are produced and found in the serum (blood plasma without the proteins used in blood clotting) of animals and indicates clinical signs of disease – death will follow soon after this.

When the microbe is excreted, it can contaminate the soil or water. Outside the host animal, the organism multiplies poorly—if at all—but it can survive over a year in the environment because of its resistance to heat, cold, and drying.

The primary cause of the spread of Johne‘s disease is contact with the faeces or saliva of an infected animal.


Because of the slow, progressive nature of the infection, signs of Johne’s disease may not show up until years after initial infection.

  • long-lasting diarrhoea
  • weight loss despite good appetite
  • Bottle jaw may also appear – fluid accumulation in the bottom jaw causing an abscess

Once clinical signs appear the animal will not recover and will continue to deteriorate.

There is no treatment for Johne’s but as always PREVENTION IS BETTER THAN CURE. It is much more cost effective to prevent than eradicate the disease once it has started spreading through the herd invisibly. The primary source of contamination is manure from an infected adult animal. It is very important to know the status of Johne’s in a herd when buying cattle as this is an easy way for Johne’s to enter a herd.


A vaccine has previously been made available in the US to prevent the risk of Johne’s which uses a mixture of killed mycobacteria and oil. It can sometimes cause large lumps at the site of injection. Occasionally these lumps will become draining abscess-like lesions. Although the vaccine is given to calves less than 30 days old, the tissue reaction at the injection site may last for life.

Another vaccine is available made from live M. paratuberculosis (but not disease causing).

The efficacy of vaccines is controversial. Studies in the Netherlands have shown that herd owners who follow the recommended management changes to control Johne’s disease could be just as successful as those who vaccinate.

Has anybody ever seen this disease before when seeing practice? Let me know in the comments!




X-ray positioning

Hi Readers,

After just completing a week of work experience at an equine clinic I learned a lot about different scans and how they are taken. The vets discussed the different views with the vet nurses so this week I’ll be looking into the names of those views so as to understand the terms being communicated between vet and vet nurse.

This diagram helped me visualise the different positions the vets were referring to. I found a table which describes the meaning of each view.

Caudal Refers to parts of the head, neck, or trunk facing toward the hind part of the body from any set point. Also refers to those aspects of the limbs above the carpal and tarsal joints facing in the direction of the hind part of the body
Cranial Refers to parts of the neck, trunk, and tail facing the direction of the head from any set point. Also refers to superior or anterior aspect of a body part or limb above the carpal and tarsal joints
Distal Refers to any part away from the center of the body
Dorsal Refers to the back or posterior part of the body; opposite of ventral
Lateral X-ray beam enters either the right or left side of the body and exits on the opposite side
Mediolateral X-ray beam enters the limb medially and exits laterally
Palmar Refers to the posterior or inferior aspect of the forelimb from the carpus, distally
Plantar Refers to the posterior or inferior aspect of the hind limb from the tarsus, distally
Proximal Refers to the end of a limb or other part closest to the point of attachment
Recumbent Refers to the animal lying down
Rostral Toward the head or nares
Superior and inferior Refers to the upper and lower dental arcades, respectively
Ventral Refers to the abdominal or sternal surface of the body
Caudocranial The beam enters the caudal aspect of the limb and exits the cranial   aspect. Difficult or impossible to differentiate from the craniocaudal view.
Craniocaudal The beam enters the cranial (front) side of the limb above the carpus and exits the caudal (back) of the limb
Ventrodorsal The beam enters the ventral surface and exits the dorsal surface.
Palmar dorsal (plantar dorsal): Taken from the back to the front of the limb distal to the proximal end of the carpus.

Horizontal Beam Views – Horizontal beam views are views taken with the patient in lateral, dorsal, or ventral recumbent positions or with the patient standing in lateral, dorsal, or ventral standing positions.


In this example, the xray is being taken in the lateral position – so enters on left and exits on the right. It is recumbent as the animal is lying down and VD stands for Ventrodorsal which means the beam enters in the ventral surface (abdomen/sternal surface) and exists by the dorsal surface (back of the body).

In this example, the dog is placed in the dorsal recumbent position with it’s forelegs extended cranially. Therefore meaning: dorsal recumbent – lying on it’s back, forelegs extending cranially – it’s forelegs extended up by it’s neck.

Another thing I learned during this experience was the plate always has to be parallel to the xray beam – which seems obvious but when holding up the leg of a horse and holding the plate at the same time, it makes being exactly parallel that bit harder! I also saw an X-ray of a horse with kissing spine and watched them use the X-ray scan to medicate between the vertebrates which I thought was amazing that the vet knew exactly where to push the needle in and the angle to hit it at just using an X-ray they had taken.


Lily Toxicity

Hi Readers,

After completing my first day of work experience at a small animal veterinary hospital, one of the most interesting cases that really caught my attention was a cat with lily toxicity. I wanted to look into this a little further before I go back in tomorrow to see how it has progressed.

All parts of the plant, including the pollen and water from the vase, are considered toxic to cats and result in severe acute kidney injury. The exact toxic dose and nephrotoxicant mechanism is still currently unknown; however, the toxicant in the lily is considered water soluble.

Lily nephrotoxicity may cause symptoms such as inappetance, lethargy, hiding, vomiting, diarrhoea, halitosis (bad breath), dehydration, excessive or decreased urination or thirst, seizures and unfortunately death.

The decreased urination can cause hyperkalemia which is high levels of potassium in the blood. Potassium is an essential electrolyte which performs several functions such as:

  • regulating nerve impulse and muscle contractions.
  • maintains intracellular volume.
  • assists in maintaining blood pressure.
  • maintains heart function.
  • maintains the body’s electrolyte balance and acid/alkali levels in cells and tissues.
  • it also plays an important role in heart, skeletal, and smooth muscle contraction, making it an important nutrient for normal heart, digestive, and muscular function.

It is the role of the kidneys to remove excess potassium from the blood via the urine, if they are no longer functioning as efficiently potassium levels can build up. This is the case with lily toxicity as it causes acute kidney failure, causing frequency of urination to also decrease. With too much potassium the heart may begin to beat abnormally and in very severe cases, stop beating all together.

Treatment includes decontamination (like inducing vomiting and giving binders like activated charcoal), aggressive intravenous fluid therapy, anti-vomiting medication, kidney function monitoring tests, blood pressure monitoring, urine output monitoring and supportive care.

Once anuria (where kidneys fail to produce urine) develops, peritoneal dialysis or hemodialysis is the only potential treatment.

Peritoneal dialysis – A dialysis technique that uses the patient’s own body tissues inside the abdominal cavity as a filter. A plastic tube called a dialysis catheter is surgically placed through the abdominal wall, into the abdominal cavity. A special fluid is then flushed into the abdominal cavity and washed around the intestines. The intestinal walls act as a filter between this fluid and the bloodstream. By using different types of solutions, waste products and excess water can be removed from the body.

Hemodialysis – A medical procedure to remove fluid and waste products from the blood and to correct electrolyte imbalances. This is accomplished using a machine and a dialyzer, also referred to as an “artificial kidney.”

I believe this can only be carried out to an animal over a certain weight.



Feline Blood Donors

Hi Readers,

While walking around one of the veterinary school open days I noticed a sign that caught my attention. It was advertising for feline blood donors, which shocked me as I thought about the number of ethical questions it raised.

I looked into the procedure of cats donating blood a little more and found this article of the procedure that occurs when a cat donates blood:

Although the article is written in a method format, certain wording of the instructions such as ‘Locate healthy happy cat’ did begin to support my original fear that donor cats may be being used solely for ‘harvesting blood’ and forgotten that he/she is a live animal. As the veterinary profession develops and we use human procedures in the vet world, I feel that ethical issues are raised such as the problem of consent. While a ‘healthy happy human’ can agree to donating blood for a good cause, not all humans are comfortable with doing so – through fear of needles for example. Unfortunately, we will never be able to speak to our feline friends to ask whether or not they are comfortable with having their blood extracted.

Granted they do not understand what is happening, probably don’t have the same fears as us and I’m sure some cats sit purring away…but should we really be doing it to save a pet for human pleasure? After all, if the pet wasn’t living in a home and suffered, say, a car accident where he/she has lost a lot of blood…he/she would probably be left to die at the side of a road – like a badger or a fox – and not taken to a vet to have its blood replaced.

Another point I have considered is the possibility of someone who has their beloved pet that they’ve become very attached to and he/she needed blood, they may buy a certain cat just to use it’s blood. Similar situations are seen in humans for transplants. I’m sure many of you have seen ‘My Sister’s Keeper’ – I do think in cases when the animal cannot consent for themself, blood and actual organs are equal in the rights we have to extract from them, although admittedly blood tissue is less risky to transplant that a whole organ.

An article by International Cat Care discusses the issues with feline blood donation:

“Most cats, for their own benefit, need to be sedated for blood donation and this in itself carries a small risk. The drugs used in sedation often lowers blood pressure, and donating blood itself can also lower blood pressure due to removing some of the circulating blood volume. These effects on blood pressure and circulation can be a particularly important if a cat has some underlying disease that neither the owner or the vet is aware of – especially things like heart disease and kidney disease.”

This is of course very different to the procedure in humans and there are questions raised as to whether this is ethical or not.

I would be interested to hear your thoughts on feline blood donors!



Are hunting dogs spreading Bovine TB?

Hi Readers,

Whilst reading last month’s issue of ‘Veterinary Record’ I came across an interesting article about hunting dogs and the spread of bovine TB.

In January of this year, 3 cases of Mycobacterium bovis infection was confirmed by APHA. In March bovine tuberculosis was confirmed in a pack of hunting hounds in south-east England leading to the euthanasia of 25 dogs. Anti-hunting groups wanted to stop all hunting with hounds as a precaution, however officials have said there is little risk of bovine TB from hunting packs.

The Animal And Plant Health Agency (APHA) said, “TB in dogs caused by Mycobacterium bovis is very rare. There is no evidence to suggest the dogs play a significant role in the persistence of bovine TB in England and that hunting with dogs contributes to the spread of the disease amongst cattle.”

The dogs, which belonged to the Kimblewick hunt, voluntarily quarantined the dogs even though the government agencies did not impose restrictions.

The League Against Cruel Sports and Hounds Off asked for a strict ban on hunting with hounds as a biosecurity measure and requested an investigation of hunting with hounds and TB spread.

In 2011, research was carried out and the results from post-mortem examinations showed the presence of TB in Irish hunting hounds. This could be additional evidence for a potential risk.

Iain McGill, a former MAFF vet (Ministry of Agriculture, Fisheries and Food) comments that hounds run across fields, defecate on the fields – which is not picked up – eat cow pats and may pick up the bacteria from slurry spread on fields. The biosecurity is poor and to look scientifically, foot swabs should be taken of hounds and their faeces tested.

How the hunt hounds got the disease is not yet known but a possible route could have been consumption of contaminated carcasses or wildlife contamination of the kennel.

A spokesman for the BVA stated, “We are not aware of any evidence of a correlation between hunt areas and bovine TB incidence. We do not think that dogs running over a field present a significant risk of transmission.”

Having read this article I agree that it doesn’t seem that dogs spreading bTB is a huge risk. As APHA stated, the spread of Mycobacterium bovis by hound is very rare and cattle are more likely to contract it from other places. The Anti-Hunting groups may be using this incidence to aid their campaign however they have not produced any evidence to prove there is a significant threat in relation to hounds and the spread of bTB. The number of cases of bovine TB in dogs seems small so far this year.

I would love to hear your thoughts on hunting hounds spreading TB or any comments on hunting in general.



Veterinary Record Vol 180 No 24