Animal Care

OUT FOR THE COUNT

Mark Newton-Clarke MAVetMB PhD MRCVS, Newton Clarke Veterinary Surgeons

Oh my goodness, how can it be that I am already writing for the Christmas edition of the Sherborne Times? The last year seems to have evaporated so quickly, but the residue that remains still has plenty of flavour. A lot more than this time last year, anyway!

Now, I have been threatening to write about anaesthesia for several months but there have been distractions and now the festive season is upon us. But maybe a nice snooze fits in well with Christmas, especially after a good lunch. So with the permission of the editorial board, I’ll forge ahead with some anaesthetics, but will try to sprinkle it with something festive. The last time I had a general anaesthetic was about 8 years ago. I remember everything very distinctly up to a point and then woke up with no memory of my hour-long sleep. More importantly, no ‘hangover’ and no pain from the surgery. And that pretty much sums up the goals of a successful anaesthetic, i.e. the patient is relaxed, has an uneventful sleep and wakes up pain-free (to be offered a mince pie if this is me on 25th Dec). What was actually going on during my anaesthetic is much more complex and is the same for the hundreds of animals that we anaesthetise every year.

Now, when I say ‘complex’ I mean many of the things we all take for granted such as blood pressure, pulse and respiratory rates and body temperature. For the anaesthetised patient, these vital statistics have to be monitored and controlled externally, as the brain is asleep and cannot perform these essential functions. Not many years ago, a finger on the pulse and the colour of the gums summed up anaesthetic monitoring, with the surgeon doubling up as anaesthetist. Nowadays we have dedicated nurses monitoring the patient continuously, and to help we have given them an early Christmas present. Called a multi-meter, this device monitors the levels of critical things like oxygen in the blood and carbon dioxide in the breath. It even has whistles and bells (the alarms) and a screen that displays all the colours of the rainbow. I even draped it in tinsel.

I have been fascinated with the control of respiration since my undergraduate days, when physiology was my favourite subject. Breathing is one of those take-it-for-granted functions that we don’t notice until it stops working perfectly, as sometimes happens when we sleep or, more relevant here, during anaesthesia. Apnoea, meaning literally cessation of breathing, is common during an anaesthetic and for some people during a normal night in bed. When I was a child, I was so excited on Christmas Eve that I never slept and probably didn’t breathe much either. I had a happy childhood!

Back to the nurses’ Christmas present, the multimeter measures (among other things) the level of carbon dioxide in expired air. Why is this important? Well, carbon dioxide, as we all know, is the product of combustion or metabolism but it isn’t just an evil waste product, providing levels are strictly controlled. If planet

Carl Dupont/Shutterstock

Earth was as intolerant of CO2 levels as most animals, raising body temperature by 1.5C would be the least of our worries. In fact, the tiniest, weeniest increase in carbon dioxide level in our bodies causes a massive change in our respiration, increasing its rate and depth. Why? Because CO2 makes acid and all our body processes are run by acid-sensitive enzymes that need to be protected.

When we are awake and exercising, the extra CO2 our muscles produce is cleverly swapped for oxygen in the lungs and our bodies’ acid level (pH) stays constant within very tight margins. When the brain is anaesthetised, the breathing reflex is depressed and if not monitored, CO2 levels can rise causing an acidosis. The part of the multi-meter that senses CO2 is called a capnograph and it tells the anaesthetist it’s time to help the patient breathe.

Although many animals and humans are anaesthetised every day, there is naturally a fear of the risk associated with this strange process. As technology improves, we can now approach the level of monitoring for patients that our brains normally perform. So if you or a family member needs a general anaesthetic this Christmas(!), take some comfort in the safeguards that the multi-metered capnograph gives us. I wonder what the clever machine would tell us during the postChristmas lunch snooze, when an over-full stomach and a few glasses of wine do nothing to help lung function!

I guess the point of this article is really to try and reassure all owners whose pets are needing an anaesthetic. Although risks do exist, they are minimised by our professional nurses and their shiny multi-meter. An excellent Christmas present for all our patients.

Last but not least, may I wish all our clients and readers of the Sherborne Times a very happy Christmas and we all look forward to waking up to a healthy and peaceful 2022.

A DAY IN THE LIFE OF A VET

John Walsh BVSc Cert AVP DBR MRCVS, Friars Moor Vets

Gobble, Gobble! After having a chat to one of our clients who provides farm-reared and finished turkeys for Christmas, I thought it would be interesting to write about turkeys – how this Christmas feast tradition started and how we enjoy them today.

Turkeys were first domesticated in what is now southern Mexico around 800BC by Olmec farmers – the birds were called ‘Huexolotl’. These farmers ate turkey meat and eggs and used their feathers to make beautiful feather capes and necklaces. Then around 200BC another group of farmers, called Pueblo, from what is now Arizona and New Mexico, independently domesticated a slightly different breed of turkey. These were also kept for their meat, eggs and feathers and musical instruments were even made out of their bones. Around 1500AD, the first Spanish invaders came to the Aztec empire in Mexico, found turkeys there and brought them back with them to Europe.

The first turkeys are believed to have been introduced into Britain in 1526 by a Yorkshireman named William Strickland. He managed to get hold of a few turkeys from American Indian traders on his travels and sold them for tuppence each in Bristol. He was obviously very proud of his acquisitions, as his family coat of arms shows off a large turkey as part of the family crest – one of the first portrayals of a turkey seen within Europe. From then on, most turkeys were imported on ships into the UK from America via the eastern Mediterranean, many of them arriving on Turkish merchant ships. So, the British assumed that these impressively large birds came from an area around Turkey and so called them turkeys!

Henry VIII was the first British monarch to enjoy turkey on Christmas day. George II attempted to introduce the wild turkey as a game bird in the 18th century. He placed a flock of a few thousand in Richmond Park but they proved to be far too easy a prey for the local poachers, who plundered them to extinction!

By the 1720s, around 250,000 turkeys were walked from Norfolk to the London markets in small flocks of 300-1,000 to adorn the Christmas tables of the rich and wealthy. They started the slow procession in August, with birds feeding on stubble fields and stopping at specific feeding stations along the way. I’m sure it would have created quite a spectacle as they passed the villages

Sergey Kolesnikov/Shutterstock

and hamlets along the way!

Having once been an abundant bird, turkeys almost went extinct in the 1930s from loss of forest habitat and over-hunting. However, recovery efforts were put in place and today the wild population is estimated to be seven million in North and Central America.

In Britain, the oldest breed of turkey is called the Norfolk Black and is originally descended from the turkeys that were first introduced in the 16th century. The modern turkey has been selected by breeding to give the right size and conformation that we require as the consumer.

Local Farm-Reared Turkeys Our client talked me through how they rear turkeys on their farm and what makes their turkeys taste so good.

In early July, mainly female chicks arrive on the farm at a day-old from a hatchery in Essex and are placed in groups of 100-200 according to their different size breeds. The chicks are sexed by the hatchery before arrival. The farmer generally chooses female birds because they will generally have bigger breast meat than the males (stags). They are given multivitamins and electrolytes in the water to help them settle in. Different strains of the same breed are selected by the farmer so that they can match the final size of the birds to their customers’ requirements. The names of these different strains are very interesting and range from the smallest called Super Mini, mediumsized birds, called Plumpy, and the largest birds called triple Bs (Broad Breasted Bronzes). These will range in weight from 10lbs to 45lbs with most birds supplied as whole birds, but the larger birds are sold for their breast meat as crowns.

These turkeys are raised to the highest standards in barns and are deep-bedded on straw for their comfort. Keeping the birds in barns means the farmer has more control of disease by preventing wild birds from introducing diseases to the flock. They are fed by hand daily and receive different feeds at different stages of their development from a local feed mill to optimise their growth and health at those times.

After a growing time of about 20 to 24 weeks the time comes to have the turkeys slaughtered. This is where farm-reared turkeys come into their own in terms of welfare and flavour. Because the facilities are all on site there is no stressful lorry journey as they only travel a few yards. After being humanely killed, each turkey is immediately ‘dry-plucked’ and finished by hand by a team of twenty people who will pluck around 300-400 birds a day. They are then left to hang for 7 days which really allows the flavour to develop. After this time, they are dressed (the internal organs and giblets are removed) and then refrigerated, ready for sale. The extra labour required for dry-plucking forms one of the biggest costs for this farmer, but they believe the investment is essential to achieve the best tasting bird for their clients. By contrast in commercial abattoirs, turkeys are plucked using the ‘wet-plucking method’, where a machine is used to pluck the bird after they have been immersed in hot water. This presents a massive saving of time with each bird plucked in around 10 to 15 seconds, but the process damages the integrity of the skin and means they have to be dressed and refrigerated immediately, not allowing time for hanging for the flavour to develop.

So, if you are having turkey for Christmas try and support local farmers to get the best tasting bird with very low food miles for your Christmas dinner.