Anatomically correct directions

An old Internet story claims that a 10-year old boy described a cow thus:

"A cow has seven sides: upside, downside, upper side, below side, right side, left side and inside. The head is on the upper side."

He is right, in a way, but the description could be more specific. We could say that the cow has head, body and legs.. but what about the neck? Is that a separate part, or does it belong to the head or the body? 

Also, a cow is easy since we all know how they look like. It's relatively easy to say where the head is (in the front, attached to the neck) or where the hind legs are (under the pelvic area, attached to the body). Alright, but where is the liver in relation to the spleen?  Where's the lump you felt, the one kinda close to the ribs but more to the top, if you look directly at the cow and you're about the same height as the cow? There's a wound in the intestines - where is it? 1".5 meters from the start"?

We need anatomical directions. Words that are unambiguous and describe things in relation to the animal itself. With these words we can describe precisely where something is.

Let's start with the main regions. We can divide the body to regions and cavities (hollow areas). A vertebrate has usually

• A head, with three cavities: 
• nasal cavity or rhinarium (the hollow space in the nose)
• oral cavity (mouth)
• the orbit (which contains the eyeballs)
• The neck, attached to the head
• The trunk, with three cavities: 
• the thorax or thoracic cavity (lung area)
• abdomen (stomach(s) and intestines)
• pelvis (urinary tract and reproductive organs)
• Forelegs
• Hind legs

To get more into detail several specific words are used to describe location. Note that they are not related to the animal's position. Think of the phrase "above the dog's hind legs". If the dog is standing, above the legs is the pelvis. If the dog is sitting, above the legs is his stomach!   

Caudal - Cranial

Caudal means to the direction of the tail (or rump in animals without a tail), and cranial means to the direction of the head. For example, an important blood vessel called caudal vena cava , which goes from the heart to the direction of the tail. They can also be used in the meaning "related to or located in", like cranial nerve are nerves emerging from the brain (cranial region). 

Dorsal - Ventral

Dorsal is to the direction of the back, and ventral to the direction of the stomach. Easy to remember when you think about people who "speak from their stomach" - ventriloquists! 

Distal - Proximal

Distal means moving away from the trunk. This could be to any direction, as long as it's away from the trunk. Proximal is to the direction of the trunk. The hooves of an animal are distal to their body, and the shoulders are proximal to the hooves. 

These words have no meaning on some organisms, such as starfish. For these we could use "peripheral" instead of distal - something away from the center.

Medial - Lateral

Let's again use a hind leg as the example. How do we describe something which is on one side of the leg? Right/left is difficult. Are you facing the animal, is it the animal's right/left, and and what if the animal is on it's side? 

Medial refers to "closer to the midline", i.e. inside of the leg. Lateral is away from the midline, i.e. the outside of the leg. Note that the when you face the animal, the right side of the right foreleg is lateral, but the right side of the left foreleg is medial... Hence, medial and lateral rather than right and left.

With these terms we can now say that the lump is 5 cm caudal and 10 cm proximal to the last rib. Or that the horse has soreness on the left medial forelimb, distal to the knee. Much better than "let me show you, if you squeeze here then OOW it kicked me!"

Sources:

Wikipedia https://en.wikipedia.org/wiki/Anatomical_terms_of_location

Coursera, becoming a veterinarian

Tinbergen's four questions

Animals, just like humans, show behaviors. If you just see a picture without a context it's hard to say what is happening - or why. For example you might see an image of a horse running. 

If you can monitor the animal for a while and see it's surroundings, you might be able to deduce what it is doing. A film could show the horse running, and a dog running after it. Looking more closely at the body language of the horse and the dog we can deduce if they're playing or there's a real chase taking place. 

(c) Picography

Now we know what is happening, but we still don't know why.

A Nobel-winning researcher Nikolaas Tinberger has formulated four questions to ask to find out why an animal is showing a specific behavior. These four requirements and their corresponding questions are

1. Cause: What controls the behavior?
2. Development: How and when is the behavior acquired in the animal's lifetime?
3. Evolution: Why the species carry on doing this behavior?
4. Function: How does the behavior contribute to the animal's survival and reproduction? 

A cause is something that motivates the animal to spend time and energy to perform a behavior. It could be an internal or external stimulus. In our example the horse was running. For example,it might have seen a predator (visual stimulus) which caused a fight-or-flight -response.  

Development explains how the behavior is acquired and how it changes. Newborn calves will seek an angle similar to the cow's hind legs and flank to find the udder. When they grow older, this behavior is lost. A behavior could also be learned, like a dog who learns that they get petted when they jump on the owner's lap.

For our example, let's assume that the horse saw a dog. The horse then escaped following it's natural instinct. Had it learned that this particular dog is friendly, this behavior would not have occurred.  Development can alter a behavior, or cause differences in how individuals express that behavior.

Evolution looks at how the behavior impacts the species. Wolves live in packs, because hunting together improves their chances of success and ensuring enough food for adults and pups. The ancestors of horses who ran from predators were more successful in raising their descendants to adulthood. This ensured that the behavior stayed with the species.

Function asks about why the behavior keeps occurring in the species. Suckling, play-fighting and mating are behaviors that survive in the species and directly impact the survival of the individual showing the behavior. Note that trained behaviors don't survive from one animal to another: they're learned. When a horse runs from a predator, the function is to escape from a  threat and to survive.

For example, let's look at the behavior of a cow picking up shredded silage. We can assume that the cow is eating. How can we answer the four questions? 

Cause: Hormonal signals create the feeling of hunger, when the intestines are getting empty. The cow sees others eating, which can promote eating behavior also in animals who are not hungry.  

Development: As a calf, the animal suckles their dam for milk. As their metabolism develops and solid food is offered, the animals learns to eat also silage, hay and similar solid feeds. Their rumen and intestines develop a bacterial flora capable of metabolizing the feed.  

Evolution: Animals who ate high-quality grass were healthier and had better chances of raising their offspring into adulthood. 

Function: To provide the animal's body with nutrients it needs to survive and to grow/produce milk.

For more information, enroll to the free Animal Behavior and Welfare -course on Coursera.  

Cow health: rumen disorders

(c) University of Minnesota

The rumen is a complex, large organ, which can hold up to 80 litres of feed. It is a sensitive organ, and any disturbances in the rumen can be lethal. Minor disturbances are quite common, and even some of the most severe cases can be solved at the farm without a vet. This text describes bloat (gas build-up in the rumen), "nail", acidic rumen and dislocation of the abomasum.

Bloat (the cumulation of gas or foam in the rumen)

The rumen contracts every 50-70 seconds, both mixing the feed and removing methane as belches. If these contractions stop or something blocks the esophagus, the gas keeps accumulating and filling up the rumen. When the rumen swells, it presses the cow's internal organs and lungs, blocking blood vessels and eventually suffocating the animal when the lungs no longer have space to expand.

(c) informedfarmers.com

Cause:  Gas can accumulate in the rumen for several reasons: the rumen stops contracting due to too low pH or nervous problems, the esophagus is blocked or the animal lies on it's side for too long. Foam can be created by the feed, often clovers or too much concentrated feed. The foam prevents the methane from being released as belches.

Symptoms: The cow's left flank swells considerably when the rumen fills with gas. The cow stops eating, and as the space for it's lungs decreases, it starts panting and gasping for breath. The condition can kill the animal in hours, depending on the severity.

Treatment: If there's foam in the rumen, the bubbles can be broken easily by giving the cow 5 desiliters of rapeseed or olive oil, or the same amount of melted butter. If the cow lies on it's side, it must be supported to the right position. Then find why the cow lies on it's side, and treat the root cause. If the rumen is swollen and the animal drools, the esophagus is blocked. The easiest way is to push the obstacle down the throat and into the rumen, thus freeing the esophagus.

Mild cases are often caused by changes in the nutrition, spoiled feed, ice cold drinking water or antibiotics given orally. In this case the cow has low appetite, and it may have pains and diarrhea. Mild cases can be treated with rumen supplements, dry hay, yeast and sugar (half a kilogram both)

An in-depth article about bloat in cattle by Alberta Agricultural and Rural Development

A sharp object in the fore-stomachs, "a nail"

Cows cannot select their feed as carefully as horses, so they may pick up and swallow foreign objects quite easily. Earlier the most common cause for this was a swallowed nail or a piece of barbwire, but luckily today those are more rare in the farms. Slaughterhouses constantly find foreign objects in the fore-stomachs: cell phones, scarves, wallets, scoops... Sometimes a coil of barbwire has fallen to the feed mill/feed wagon, got shred to small bits and been mixed with the feed, server to the whole cattle. Most often the cause is the carelessness of the people in the farm, leaving nails, hammers etc where to cows can reach them. Sometimes the animals can swallow foreign objects if they escape their pasture or barn.

Cause: When a foreign object is swallowed, it can either block the esophagus, get stuck in the digestive tract or pass through it. If the item is sharp, it may poke through the stomach walls, causing an infection. The item may become encapsulated in the digestive tract, whereupon tissue is grown around it, preventing the item from being removed or harming the organs. The reticulum is right next to a cow's heart. If a sharp object penetrates the reticulum wall, it may pierce through to the heart, causing a sudden death.

Symptoms: Symptoms vary based on the item swallowed and what it causes in the digestive tract. If the item is sharp and pierces any tissues, the animal shows signs of pain (restlessness, kicking of the abdomen). The cow may stand with it's back arched. Foreign objects in the esophagus or rumen may cause the animal to vomit, and in severe cases the cow will regurgitate even the water it drinks.

Treatment: If the foreign object is metal, the animal can be fed a magnet, which then stays in the rumen for the rest of the cow's life. The magnet catches any metal items, preventing them from pricking through the rumen walls. The animal should be tied to a stall, and it's front end should be raised. If the condition doesn't improve in 1-2 days, the foreign object must be removed surgically.
 

Acidic rumen

The pH of the rumen should always stay between 6-8. Sometimes if there's too much concentrated feed or not enough salive to buffer the contents, the pH of the rumen can drop quickly. Ruminants develop symptoms of acidic rumen when the rumen pH is lower than 5,5. Acidic rumen exposes the animal to problems with the abomasum, laminitis of the hoof, rumen wall damage and liver abscesses.

Cause: Too much starch and sugar in the feed cause very strong fermentation in the rumen, creating more acidic side products than the metabolism can handle. The feed may also require little chewing or ruminating. This condition offen occurs near calving, when the cow gets plenty of concentrated feed, but eats little roughage. Acidic rumen is also common with bulls to be slaughtered, since they are fed mostly concentrated feed.

Symptoms:  Loss of or variable appetite, wet feces, undigested feed in the feces, dropping of cuds (ruminated pieces of feed), mild bloat. The animal may lose body fat.

Treatment: Treating this condition once helps very little. Sodium bicarbonate (100-200 g / day) may relieve the worst symptoms, but the most important thing is to adjust the animal's diet to have enough hay or straw, and that the possible silage is not shredded too short. The diet must have only moderately starch and sugar, and they should not be given all at once. The animals must have access to clean water at all times.

Displaced abomasum

Abomasum is the last of the cow's stomachs, and the only which functions like the stomach of monogastric animals. As shown in the picture above, abomasum lies at the bottom of the abdomal cavity, behind the reticulum. Abomasum usually rises up to either side of the animal.

Picture adapted from The University of Missouri

Cause: The abomasum is displaced if its walls lose their tonus and the abomasum filled with gas. The cause is still uncertain, but high level of glucose and low level of calcium in the blood are contributing factors. Acidic rumen is also a risk, because it sends forward unfermented feed, which ferments even in the abomasum, creating gas and lifhting the abomasum up like a balloon. Stress and sickness near calving may also cause dislocation of the abomasum.

Symptoms: Loss of or variable appetite, no fever, slightly elevated levels of ketones. When pressing an ear against the animal's flank and tapping it with a finger, a distinct, metallic "ping" sound can be heard.

Treatment: Surgical treatment is the most effective, and can be done on-site. Gas is removed from the abomasum, and it is secured to its place with a few stitches. Another old remedy is to roll the cow over on it's back or making the animal run, but these provide often only temporary relief.

Cow health: Metabolic illnesses

Cows today produce much more milk and meat than their ancestors ever did. They are fed optimum diets and kept in maximum production the whole time, regardless of how unnatural that is to an animal. This causes many problems and illnesses to cows and calves. Most common ones are milk fever, ketosis (acetone disease) and grass staggers (grass tetany, hypomagnesemia, winter tetany).

Milk fever

Milk fever can occur in cows and pigs right or soon after calving / parturition. If not treated quickly, severe milk fever can kill the animal in one day.

Cause: Milk fever is caused by low levels of calcium in the blood. After calving the milk production starts on high efficiency, and a lot of calcium is suddenly needed. This calcium is released from the animal's bones. If calcium cannot be released quickly enough, the calcium needed for muscles to function is used instead, causing milk fever. Milk fever can be prevented by keeping the cow in very low-calcium diet during it's dry period, giving the body time to increase it's calcium release mechanism.

Milk fever can occur later in the production period if the amount of calcium in the diet suddenly drops, or absorption of calcium is decreased due to another illness. Heifers and cows with low milk yield rarely suffer from milk fever.

Symptoms: Milk fever is not actually a fever, but paralysis. First the cow stops eating, it's skin feels cool, and it's muscles of the cow may tremble. Soon the large muscles in the legs cannot support the animal's weight anymore, and it falls, unable to stand. The cow may lie on it's side, whereupon it's rumen may fill with gas, suffocating the animal. Rumen movements stop, and within a day the animal dies due to paralysis of the lungs, liver and heart.

(c) www.nadis.org.uk

Treatment: Intravenous infusion of calcium is needed to raise the level of calcium in the blood. This is done by a vet, who must also listen to the animal's heart while infusing the drug (calcium is potentially toxic, and may cause heart failure). Only enough is given for the cow to get up and start eating, so it can fill it's own calcium levels naturally. Sometimes another treatment is needed, if the diet contains too little Ca. This can be given orally by anyone.

The risk for ilk fever can be reduced by ensuring that the dry period diet is low in calcium. The diet can also be tailored to affect the cation-anion balance of the cow's body: by lowering the pH of the body (increasing anion salts) three weeks before calving, the calcium is released from the bones more effectively. This can prevent up to 50 % of the cases of milk fever.

Milk fever in The Merck Veterinary Manual

Ketosis

(c) Valley Veterinary Clinic

Cause: Ketosis is caused when the cow has too little glucose in it's blood. Cows synthetise glucose in their liver, but this creates acidic ketones. Normally rumen microbes can use them as energy. If too much glucose is formed this way (due to lack of it in the blood), the microbes cannot use all of the ketones, and the pH of the animal drops.

Earlier ketosis occurred right before milk production peak, when the cow ate less than it needed to produce milk. Nowadays ketosis occurs commonly for recently calved fat cows, because their body releases more fats for energy than their liver can handle. The liver collects fat, and can no longer produce glucose, leading to ketosis.

Symptoms: Decreased appetite especially for concentrated feeds, eating of strangle substances such as dirty straw, apathy, quietness, loss of weight, dry feces, acidic smell in the animal's breath (not all people can smell ketones). Ketone levels in the milk are elevated. Cows may drop cuds, because they are acidic and thus taste bad.

Prevention and treatment:  More important than treating ketosis is to prevent it altogether. Make sure the cows are in good shape before calving, which also makes the calving easier and reduces the following metabolic stress. Avoid cows with ultra high milk yield, because they are more prone to ketosis. Adjust the diet for each animal so that they get enough precursors for gluconeogenesis even if their appetite is low. If possible, limit milking so the cow needs less glucose for production.

Treatment for ketosis is intravenous infusion of glucose, injection of cortisone, propylene glycol given orally

Ketosis in the The Merck Veterinary Manual

Grass staggers (grass tetany, hypomagnesemia)

Grass staggers is a form of convulsion caused by acute lack of magnesium. Young grass is low on magnesium, so this disease often affects cattle which has just been let to pasture.

Cause: Grass staggers is caused by lack of magnesium. Grass in the pasture can have too little magnesium if the grass is young, or it has been fertilized with too much potassium and nitrogen and too little magnesium. Absorption of magnesium is decreased if the diet has over 20 % of protein, over 3 % of potassium or too little fiber. Appetite also affects to how much the animal eats, and how much it thus gets magnesium.

Symptoms: When the magnesium level in the blood decreases, the animal cannot no longer control it's muscles. First the animal appears overly alert and tense, it is restless and its movements are uncoordinated. Soon it's muscles convulse, and the animal gets a seizure. The cow is sweaty and it's body temperature is high due to constant muscle tension.

Treatment: Magnesium must be injected to the animal as soon as possible, for it may die at any moment. Sometimes cows with grass staggers die just from the needle prick, so even quick treatment may not save the animal. If the injection is given and the cow picks up, magnesium must be given orally for five days. The diet of the whole cattle must be checked! If the cause is low Mg levels of the pasture grass, every animal in the herd may get sick and die.

Hypomagnesemic tetany in The Merck Veterinary Manual

Cow health: Mastitis and teat injuries

Whether one keeps beef or dairy cows, the production is still dependent on the udder health of lactating cows. The udder is a delicate organ, which is very susceptible to damage and infections in today's high-stress, high-production environment. 

Mastitis

(c) http://www.agcanada.com

At every farm, approximately 30 % of cows suffer from clinical or subclinical mastitis, the infection of the udder. Since mastitis ruins the milk from the infected quarter of the udder, it causes loss of milk (loss of profit). Mastitis also increases the work load, may lower milk yield permanently and is expensive to treat because it's so common. It's symptoms therefore are the body's normal defense mechanism against viruses, tissue damage and bacteria. Therefore mastitis has very different symptoms depending on the causing agent.

Cause: Mastitis is often caused by bacteria like Escherichia coli, Staphylococcus aureus, coagulase-negative staphylococcus, Streptococcus agalactiae, Str. uberis, Str. dysgalactiae, Arganobacterium pyogenes or Corybacterium bovis. It is important to test the infection milk to find out which bacteria is causing the infection, so the correct preventive measures can be taken. E. coli for example comes usually from filty stalls, Str. dysgalactiae is found with injuries and Str. agalactiae infection is always from another cow.

Symptoms: Symptoms vary, but the most common ones are fever, swelling and warmth in the infected part of the udder, abnormal milk, reduced milk yield, loss of appetite and reluctance to give milk due to soreness in the udder.

Treatment: "Common treatment" may be costly and useless. For effective treatment the cause of mastitis must be studied. Str. agalactiae responds well to penicillin, but E. coli may need stronger antibiotics plus supportive treatment, because it often also causes severe diarrhea. C. bovis infections are best treated with teat disinfectants and drying off (stopping her from lactating until the next calving).

Prognosis: After severe mastitis the infected quarter may go dry entirely, or it must be amputated as a treatment. This leaves the cow with only three teats, decreasing its milk yield. Some cows which get mastitis often may need to be slaughtered. An epidemic of mastitis is always a cause to re-evaluate the conditions in and cleanliness of the barn.

Teat injuries

(c) http://eagleburra.com.au

Teat injuries can be problematic on their own, since they cause pain and bloody milk, but they may also lead to mastitis. Some cows may have congenital teat deformations.

Cause: The cow may step on her teats if she cannot lie down or stand up naturally due to slipper floor or other environmental problems. In a cramped barn, cows may step on each other's udders. Adult cows sucking milk from each others, fights and faulty milking machinery may also cause teat damage.

Symptoms: In chronic (long-term) teat injuries the milk channel gets thicker over time and may get clogged. Round, hard growths may be felt in the teat. Milk letting is slow. In acute (sudden) injuries the milk may be bloody, teat shows external damage.  A gangrene may develop on to the skin of the udder, and the udder may turn blue.

Treatment: Injured teats must be kept clean. The cause for the damage must be removed, if possible. Deep or long wounds in the teat should always be treated by a vet, so they heal better. Gangrenes can be left to heal on their own, but treating a possible infection and keeping the udder clean are very important. Chronic teat injuries like clogged milk channels can be surgically opened by a vet, but the prognosis is not good.

Prognosis: Prognosis depends a lot on the nature of the injury. Small acute injuries often heal well. Chronic injuries may keep getting worse if the cause isn't quickly removed, and have worse prognosis.