Gear up for Spring

Time to Gear up for Spring

 

Here’s to Spring in February! What a winter – Jessie, Hayley, Gina and I were working in our shirtsleeves during Mother’ Nature’s generous gift of a warm early February and now winter is having her last go at us again. I hope you were able to take advantage of those beautiful days to get out with your horses. The ups and downs in temperature have been a bit hard on our equine friends this winter. I’ve been treating an unusual number of impaction colics, most of them mild and responding well to treatment.

They are a reminder of how important it is to keep after hydration during the winter months. On these warm days excercising horses and blanketed horses tend to sweat – loosing precious body water – then the temperature drops at night, water freezes, horses drink less and risk dehydration. Horses require 10-12 gallons of water daily. This amount increases substantially in the face of body fluid loss through sweat. Horses have been shown to decrease their voluntary water intake when the temperature drops below 45 degrees.

In addition, before the weather became warm, we had that nasty stretch of freezing snow that made it difficult for horses to move around comfortably. Lack of exercise also contributes to colic through decreased gut motility and processing of fiber through the intestinal tract.

Finally, while it is true that horses burn more calories during cold weather, erratic increases in grain can cause problems. Sudden change in carbohydrate load to the digestive system can cause gas accumulation, bowel distension, and subsequent abdominal pain. Put it all together and winter is a challenging time for good management. Keep these basics in mind:

1) Check your horse’s water source 2x daily – be sure it is clean and free of ice

2) Exercise your horse – even if it is just taking him out for a nice 20 minute hand walk – even in the worst weather!

3) Make feed changes gradually – good quality hay is always the safest thing to feed – be sure there is adequate fiber in your horse’s diet!

Here is the best news of all – Winter is Almost Over! Thanks for being part of the HIghDesertEqine.com family – I look forward to seeing you on a clinic day in March. See clinic schedule below.

Gratefully,
Chrysann Collatos VMD, PhD, DACVIM
High Desert Veterinary Service

                          Spring Vaccination Clinic Schedule.

 As always I’m there to answer your questions, and also offer routine health care services on clinic days. Routine spring health care includes vaccination against E&W Encephalitis, West Nile, Tetanus, Influenza and Rhinopneumonitis plus deworming, an oral exam and sheath cleaning for geldings.

Call the office to reserve an appointment.

BE SURE TO LEAVE THE FOLLOWING INFORMATION:

Name, Phone #,  Date you request, Number of Animals, and the Services needed.

We will return your call three days before your clinic with an estimated time of arrival at your address.  Please be sure horses are caught and haltered 30 minutes beforehand.

Location                                               Date

Rancho Haven/Sierra Ranchos1              Sat  March 5

Rancho Haven/Sierra Ranchos2              Fri  Mar 11

Red Rock North/Silver Knolls 1                Sun Mar 6

Red Rock North/Silver Knolls 2                Fri Mar 11

SpanSprings/Palomino Valley 1              Mon Mar 7

SpanSprings/Palomino Valley 2              Sat Mar 12

Antelope Valley                                          Sun Mar 13

Golden/Lemmon Valley                            Sun Mar 13    

South & West Reno                                  Tues Mar 15

Golden/Lemon Val/South Reno               Fri Mar 4

For additional savings, you can schedule your own mini-clinic as long as you have at least 10 horses at a single location.  Call the office to make such arrangements.

Price List – Clinic day only

Farm Call/Fall Exam              $17.00              

West Nile (Prevenile)              $32.00

FluRhino                                   $26.00

Tetanus/ Encephalitis             $14.00

Intranasal Strangles                $32.00

Rattlesnake Vaccine*             $32.00*

Ivermectin Deworm                 $14.00

Coggins Test                           $22.00

Sheath Clean w/sedation       $35.00

* 2 boosters are required after this initial dose – call the office or e-mail us if you have questions.

Ask Dr. C what vaccines are best for your horse based on age, environment, and activity level.

2/22/2010 - Omega-3's & Colic

Vet Tip of the Day: The role of Omega-3 Fatty Acids in Colic prevention
Key Words: Colic, Polyunsaturated fat, fatty acid, cell membrane, endotoxin

Since you are now budding experts on the subject of endotoxemia and its devastating effects on horses with gastrointestinal disease, I thought we would conclude this segment on colic with a discussion of Omega-3 fatty acids.  You've may have heard a lot of buzz about these special fats; following are some facts about Omega-3's and how they can help protect your horse from some of the terrible consequences of endotoxemia.

Omega fatty acids - What are they?

This part is pretty dry, but it will only last a few sentences, so hang in there. Our bodies derive four types of fat from food:cholesterol, saturated fat, monounsaturated fat, and polyunsaturated fat. Omega-3 fatty acids are polyunsaturated fats. They are called omega-3 because a certain chemical bond between two carbon atoms occurs at the third carbon in this fatty acid chain of carbons. The other major polyunsaturated fat in our diet is Omega-6 fatty acid (first double bond at the sixth carbon).

Omega-3 and Omega-6 fatty acids are considered “essential” fatty acids, because neither horse nor human can construct these substances internally. They must be obtained in our diets. While both O-3 and O-6 are necessary for good health, we and our horses eat diets that are relatively high in Omega-6 fatty acid and deficient in Omega-3. As we will see, it appears that an ideal ratio of dietary O-3 to O-6 is about 2:1, while most of us are eating these fatty acids in a ratio more like 1:10 or even 1:20.

Omega fatty acids - What is their function?

Consider the building blocks of our bodies. We and our horses are amazing machines, composed of a group of organ systems that works in harmony to create life. Each of our organs is a mass of cells, and each organ has its own distinctive cell type. Liver, kidney, skin, nervous tissue, brain, blood vessel walls - each has its own unique cellular architecture. However, all of these cell types are encased in the same basic cell membrane. Guess what our cell membranes are made of? You’re right - they are made of fat!

Cell membranes are composed of a double layer of phospholipid, a complex fat containing Omega-3 and Omega-6 fatty acids. The cell membrane is like a telegraph system; signals from outside the cell are communicated to the inside through the cell membrane. The composition of the cell membrane determines in large part how signals are translated from outside to inside; the cell membrane makeup greatly influences the cell’s response to a given stimulus. Specifically, a cell membrane enriched in Omega-3 fatty acids is protected from many of the inflammatory responses to injury that are produced by an Omega-6 enriched membrane. 

If your horse experiences a serious colic in which gut motility is disrupted, remember that this leads to a die off of bacteria normally present within the bowel.  Some of these bacteria contain endotoxin, which is absorbed into the blood stream through the compromised gut wall of your colicky horse.  This endotoxin attaches to cell membranes in your horse's system, sending a series of telegraph signals across cell membranes and from cell to cell that lead to the production of many small molecules responsible for inflammation, shock, and cardiovascular collapse.  If your horse's cell membranes are enriched with Omega-3 fatty acids, the severity of the inflammatory response to these signals is dampened, resulting in less devastating effects on your horse's circulatory system.

Omega-3 Fatty Acids - Where do we find them?

Omega-3 fatty acids are relatively abundant in oily, cold water fish such as tuna, salmon, and mackerel. These fish contain large amounts of two Omega-3's, eicosapentaenoic acid (EPA) and docosahexanoic acid (DHA). Vegetable sources of Omega-3's include kelp, as well as flaxseed, canola, walnut, and soy oils. The latter 4 oils contain alpha-linolenic acid (ALA) the third major Omega-3 fatty acid. One should remember that all of these sources of Omega-3 fatty acid also contain Omega-6 fatty acid. Once ingested, the Omega-3 and Omega-6 fatty acids compete for the same processing sites in the body, emphasizing the importance of the balance of O-3 and O-6 in the diet.

For us, consumption of Omega-3's is easily achieved by eating fish. Since 2000, the American Heart Association’s dietary guidelines have recommended that healthy adults eat at least two servings of fish per week. Alternatively, there are many encapsulated fish oils available: people with existing cardiovascular disease are encouraged to take 1 gram of EPA and/or DHA daily.

For our horses, there are an increasing number of supplements and concentrate feeds on the market that are enriched with flaxseed oil to supply Omega-3 fatty acids. Unfortunately, we have no good information on how much a horse should eat to achieve a beneficial result. Therefore, while there is mounting evidence that dietary enrichment with Omega-3 fatty acids will improve your horse’s overall well-being, we are still guessing with our dietary supplementation. One positive note concerning flaxseed oil, the primary source of Omega-3 for horse consumption: flaxseed oil contains three times more Omega-3 than Omega-6 fatty acid, making it likely to shift the overall dietary balance of O-3 to O-6 in the right direction, toward 2:1.

How will Omega-3's help my horse?

We may not know how much to feed, but we do have some experimental evidence concerning the beneficial effects of Omega-3 fatty acids in horses. In the laboratory setting, researchers have looked at the effects of Omega-3 fatty acids on various equine cell types. Cells from joint linings, or cells from the abdominal cavity, for instance, can be grown and maintained in the lab. The cell cultures, as they are called, represent miniatures of the whole horse. Each cell type can be “fed” diets containing varying amounts of Omega-3 fatty acids. Then, cells can be subjected to an experimentally induced injury and the cell’s response to this injury can be measured. In fact, a beneficial effect of Omega-3 fatty acids on equine intestinal cells has been demonstrated in this experimental setting.  The presence of Omega-3 fatty acids in the cell membrane reduces the cell's inflammatory response when exposed to endotoxin.
There is much left to be learned concerning the role of Omega-3 fatty acids in our overall health plan, for our horses and our selves. However, early evidence weighs in strongly in favor of a beneficial effect with no apparent associated dangers. Educate yourself more about the world of Omega-3 fatty acids and make an informed decision concerning the inclusion of an increased amount of this essential fatty acid in your horse’s diet.

A bit of trivia: who remembers the heart-rending movie Lorenzo’s Oil? The story of a child with a degenerative nerve disorder. Guess what the magic oil was? Right again - Lorenzo’s Oil was an Omega-3 fatty acid.

Fri 2/19/10 - Colic - Clinical Case

Vet Tip of the Day: Fatal Colic
Key Words: Ischemia, Shock, Banamine, Heart Rate, Pain

My assistant Jessie and I had a hectic day - three emergencies, each in a different geographic area, on top of scheduled calls.  Our third emergency was the horse pictured here, who had an acute onset of abdominal pain.  Unfortunately, the outcome was not positive.  I am going to share this case with you so that perhaps by learning from this lovely old horse we can give some small value to his death.  The education he provides will be his last gift to us.

Chance was a 23 year old gelding.  His nutrition and preventive health care were excellent, and he was in very good condition.  He was used as a school horse for beginning riders and had no previous history of colic.  He was normal this morning, but suddenly around 2 PM began to look back at his abdomen  and paw at the ground.  Within 20 minutes these signs had progressed to the point that Chance would crumple to the ground and roll unless one person led him forward while a second person encouraged him to stay up with a longe whip.  We arrived 30 minutes after the onset of signs.

Chance's behavior is classic for acute, severe colic.  Mild signs of abdominal pain include looking back at the abdomen,  standing in a stretched out posture as if trying to urinate, loss of appetite, occasional pawing and spending unusual amounts of time lying down.  Moderate pain is characterized by persistent pawing, and frequent lying down and getting up.  As pain becomes severe, signs include falling suddenly to the ground and rolling violently.

When we arrived, it was impossible to perform a physical examination on Chance because as soon as he stood still he would attempt to throw himself down.  I administered a mild sedative intravenously as he was walking.  After 10 minutes this medication had had no effect so a second, more powerful sedative/analgesic combination was given.  Five minutes later Chance would stand without trying to roll, but was heavily sedated and not normally responsive to stimuli.  At this time his heart rate was moderately elevated (52 beats per minute/normal range 28-40), he had no gut sounds, and his gums were pale pink.  On rectal examination I could palpate an increased quantity of heavy ingesta in the large colon, which was displaced from its normal position.  A stomach tube was passed through the nose into Chance's stomach, and when a siphon was applied it was determined that there was no build up of fluid in the stomach.

Although I had not felt anything too alarming on rectal exam, at the time of our initial evaluation Chance has only been showing signs of discomfort for 30 minutes.  And in this time his degree of pain had escalated rapidly.  At this point my assessment was that Chance was suffering from an acute, severe colic.  Based on the severity of pain (which was only controlled temporarily by a very potent pain relieving injection) and the rapid progression of signs I was suspicious of a strangulating obstruction, or a twist in the bowel that had cut off blood supply to a section of the intestine.  These sudden strangulating lesions cause the most immediate, severe, and unrelenting pain of all forms of colic.  The strangulation can occur in either the large or small intestine.  Eventually the normal bowel becomes very distended in front of the strangulation, but this takes a few hours to develop, and during this time the rectal exam may be deceptively normal.  Unfortunately I couldn't accurately assess Chance's heart rate because I had to sedate him before I could listen to his heart and the sedative lowers heart rate significantly.  To answer one of yesterday's questions, of all the information we can gain from a colic, including sophisticated laboratory data, the two most sensitive indicators of the severity of the situation are heart rate and degree of pain.

At this point, Chance becomes a surgical candidate.  The only hope for horse's with strangulating lesions is rapid surgical intervention.  Once a significant portion of bowel looses blood supply,  endotoxic shock (see yesterday's blog) sets in very rapidly. Cardiovascular collapse and death can occur within 4-6 hours in the most severe cases. Because of Chance's age and economic constraints, surgery was not an option.  The only hope was that my assessment was incorrect.  I gave Chance a dose of flunixin meglumine (Banamine), a powerful anti-inflammatory medication which relieves gastrointestinal pain and combats the effects of endotoxemia, and we waited.

Within 30 minutes, when the sedative/pain killer was wearing off, Chance became very painful again.  With the recurrence of pain now Chance also exhibited an elevated heart rate (80 beats per minute), muscle tremors, a continued abscence of gut sounds, and deteriorating mucous membrane color.  His gums took on a grey/purple hue, which is hallmark indicator of cardiovascular compromise, or shock (see picture).

Euthanasia was performed 3 hours after the onset of Chance's colic.  Within that short time he had progressed from a healthy horse to one with multiple signs of severe endotoxic shock, the result of a strangulating intestinal lesion.

Long term (over 1 year) survival of horses with severe strangulating lesions after surgery ranges from 30 - 60%, depending on what study you read.  Estimated cost of surgery and hospitalization for these severe cases is 7,000 to over 10,000 dollars.  These are the worst case scenario colics, and they are by far the least common.  Colics requiring surgery that do not involve dead bowel, such as simple large colon displacements, have 85 - 90% long term survival rates, with cost estimate around 6,000 dollars.  And while Chance's story is a tragic one, remember that the vast majority of colics do not require surgery, and respond well to medical therapy.


The key to preventing colic is regular preventive health care, excellent quality diet, and a regular exercise program.  Unfortunately, colic can be an  indiscriminant killer, and as Chance showed us today, even horse's receiving the best of care can be stricken.  Chance was a wonderful horse, and will be sorely missed.  Hopefully by sharing his story he will help bring veterinary assistance to another horse with the chance for a better outcome.

Thurs 2/18/2010 - Colic

Vet Tip of the Day: What is Colic?
Key Words: gastrointestinal, endotoxin

I had a special visitor today.  Dr. James Moore, from the University of Georgia, was in Reno speaking at the AERC National Convention.  Dr. Moore was my major professor when I completed my doctoral research back in the early 90's.   He is a brilliant surgeon and researcher, and has spent much of his career investigating the factors that make colic such a deadly disease in horses.  As we ate pizza and swapped old stories this evening, I thought I would use his visit as inspiration for today's Vet Tip of the Day.

Colic is a very general term that refers to pain originating from the abdominal region.  In horses, colic has been associated with any disease of the gastrointestinal (GI) system that causes clinical signs of  GI pain.  The most common mechanisms of GI pain are distension and loss of blood supply.  Both of these occur when a section of bowel shifts into an abnormal position, or rotates on its own access.  The equine gastrointestinal system is composed of the esophagus, stomach, small intestine, cecum, large colon, small colon and rectum. The large colon is divided into 4 sections, which lie folded on each other, running along either side of the abdominal cavity. The intestinal tract of an adult horse, from stomach to rectum, is over150' in length!  Here's the most amazing part: the vast majority of the intestinal tract is free to move all over the abdomen,  only the cecum is attached at its base to the body wall.  Therefore, whenever the horse's complex intestinal motility pattern is upset, loss of coordination in progressive motility can lead to displacement of portions of the small intestine, or any of the colons.  When this occurs food material cannot move in an organized manner through the GI system.  When food transit is slowed, the bowel wall becomes distended.  This distension causes pain and further disrupts motility.  If the bowel rotates on itself (torsion or volvulus), a complete obstruction occurs, with loss of blood supply and severe distension, which can rapidly lead to death.

What kills horses with severe colic?  When a piece of the intestinal tract loses motility, becomes distended, or has reduced blood supply, several things happen.  First, the contents of the intestine stop moving. Second, the wall of the intestine begins to lose integrity as its oxygen supply is cut off due to lack of blood supply.  The intestinal contents are normally rich in bacteria which aid digestion.  However, when gut contents stop moving, the chemical environment in the gut contents is altered, resulting in bacterial death.  The dead bacteria decompose, and are absorbed across the now unhealthy gut wall into the blood stream.  One of the components of the bacterial cell wall is called endotoxin or lipopolysaccharide.  Endotoxin is a very powerful toxin to which horses are exquisitely sensitive.  Very small amounts of endotoxin in the equine blood stream cause severe inflammation, which leads to shock, cardiovascular collapse, and ultimately death.  So horses which die due to colic are actually poisoned by the contents of their own gastrointestinal tract.

Less serious colics, caused by temporary delay of transit through parts of the gut, such as large colon impactions, often respond to conservative treatment including anti-inflammatory analgesic medication such as flunixin meglumine (Banamine) combined with administration of fluid, and mineral oil via a naso-gastric tube.  When a complete obstruction occurs, however, surgical intervention is necessary to empty the affected bowel and return it to a normal position.  In the most severe cases, where segments of bowel have had severe compromise to their blood supply, surgical resection (removal of the affected bowel) may be necessary.

Can you list 5 signs of colic (gastrointestinal pain) in order or increasing severity?
Do you know what the 2 most reliable indicators are to determine whether a horse with colic requires surgery?

Answers in tomorrow's Tip of the Day.