Cushings/PPID Primer, Part I

Cushings Disease is something that we have a lot of experience with. In fact we have so much experience in identifying, treating and managing Cushings horses we have spent the last few months participating in a clinical study with one of our veterinarians and the manufacturer of the drug Prascend. Many people get confused when they hear the name Prascend, however the actual drug in Prascend is pergolide mesylate, which has been the drug of choice for treating Cushings in horses for many years.

Since we test, treat and live with so many horses with Cushings (more appropriately known as PPID now) we spend a lot of time discussing this with our vets and our clients. I decided it was time to write a series of blog posts that contained the answers to the questions we get asked over and over. Keep in mind in these posts that I will be attempting to explain things in layman's terms, thus I am grossly oversimplifying many of these explanations to allow for ease in understanding of the big picture. In today's post, Part I, am going to attempt to explain what this disease is.

Cushings is one of the most common metabolic disorders, or disorder of the endocrine system, in horses. Cushings disease is now officially called PPID (Pituitary Pars Intermedia Dysfunction) in horses, although most people generally still refer to it as Cushings. In horses Cushings is now referred to as PPID since it was discovered that the mechanism of the disease is different of that in people in dogs. 

PPID causes the pituitary gland to overproduce hormones. The pituitary gland, which is sometimes referred to as the master gland, is located at the base of the brain and is made up of three lobes in a horse: pars distalis, pars intermedia, and pars tuberalis. PPID  specifically affects the pars intermedia lobe of the pituitary gland, hence the name Pituitary Pars Intermedia Dysfunction.

Under normal circumstances the pars intermedia acts to regulate and suppress the secretion of certain hormones. One of the hormones that is kept regulated via a suppression mechanism is ACTH. PPID is initiated when hypothalamic dopamine producing neurons fail. When this failure occurs the suppression mechanism of the pars intermedia fails. 

The failure of the suppression mechanism leads to an increased hormone production in the pars intermedia. The result of this increased hormone production means the hormone levels within the pars intermedia, including ACTH, can be up to 100 times higher than that in a horse that does not have PPID. The cells in the pars intermedia divide and enlarge without regulation, causing the pars intermedia to increase greatly in size.  At the same time that the pars intermedia lobe of the pituitary gland is expanding, it forces the other two lobes of the gland to become compressed.  

Thus a PPID horse has a greatly enlarged pars intermedia lobe that is busy over producing hormones. This overproduction leads to a variety of symptoms in horses, and rarely do two PPID horses present with exactly the same symptoms. The most common initial symptom we see are issues with the haircoat. The hair is overly long and/or very dry, or the hair doesn't shed properly or shedding is delayed, or some combination of these. The second most common symptom we see is an over-consumption of water. The third most common symptom we see are a poorly functioning immune symptom, or better put as an increased susceptibility to infection. The horses might be prone to skin infections, have chronically puffy and/or runny eyes, and other such symptoms that are easy to write off and attribute to weather and other factors. There are a lot of other symptoms we've seen as well including irregular fat deposits, a lethargic attitude, muscle wasting, etc. 

We've seen these symptoms presented very subtly and sometimes in very obvious ways. Sometimes the horse might have only one subtle symptom, other horses start presenting more than one symptom, and some pretty much scream at you "I have PPID, begin treatment now." We've had horses in their early teens test positive as well as older horses. One extremely common misconception is that PPID/Cushings is an "old horse" disease. This has been soundly disproven clinically. As a horse ages the odds of having PPID continue to increase, but PPID has now been clinically verified in many horses as young as five.

In my next post on the topic I'll discuss testing and treatment. I want to state again that in an effort to make my explanations easy to understand I am grossly oversimplifying many things. My point isn't to turn all of us into clinical experts on all aspects of PPID, but simply to help us all understand what it is, how to test for it, treat it and manage horses with it. I hope the information will be helpful to at least a few people!

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Lofty and Faune having a particularly relaxing day with George, Gibson and Flyer

a closer look at Lofty and Faune (and George)

Dutch, Blu and Murphy . . . 

. . . didn't bother to lift their heads as the turkeys strolled past them

Kennedy and Oskar

Duesy and Remmy (Bruno in the background)

Gibson

Walden, Hesse and O'Reilly

pony power; Norman, Traveller and Cuff Links

Donovan, Oskar and Johnny

Rocky, Largo and Clayton

Sunday Stills

Blu and Nemo

Johnny and Sebastian

Bruno, Lucky and Lightning

Griselle and Sparky

Calimba and MyLight hanging out

Tony and Baby

Flyer and Faune

Cocomo and George having a foggy morning grooming session

Thomas doing his routine pre-meal stretch with Homer watching

Romeo and Lotus

At Least The Grass Is Free

We all hear certain things that, for whatever reason, really push our buttons. A comment I hear from time to time is something along the lines of "your expenses must be so low most of the year because the grass is free."  When someone makes a comment this stupid (sorry to be harsh but it is true) I generally don't respond. Sometimes I'll make a half-hearted attempt at correcting their overwhelmingly wrong interpretation of what it takes to run our farm, but usually I don't bother and just try to change the subject.  As I was watching Jason mowing in one of the pastures yesterday it made me think about how "free" the grass is.

In case you haven't picked up on where this is headed grass is not free. In fact grass is expensive in both money and time. First of all you have to pay for the land. Even when purchasing cheap land at $3,000-$5,000 an acre that means we have $6,000 - $10,000 per horse tied up in land costs as we allow two acres per horse. After we've purchased our free grass, I mean land, then you have to fence it. Four board wood fencing in our area costs between $6-$7 per foot, with gates costing double the amount per foot. The variation in cost depends on if each post is set in concrete or if the posts are just pounded in and some other factors. So to fence off one pasture you are looking at another $10,000 minimum, and that is for a pretty small pasture. 

Jason using some of our free equipment to maintain our free grass

Then your free grass needs some run-in shelters at about $7,000 per shelter.It would be so nice if the fence maintained itself and the horses didn't scratch their butts on it, crib on it, and do other horsey things that break boards. So after you've paid for the fence you get to keep paying for it as you replace boards. And those replacement fence boards (free of course) are all cut with a $600 chain saw. Why do you need an expensive chain saw? So it will run when you need it to. Anyone who has used chain saws on a regular basis will know what I mean by that. 

Then we have this free grass that has to be maintained. We have two tractors and three bush hogs. Our critics could rightly point out that three bush hogs is overkill and they wouldn't be wrong. However we actually do need two of them.  The 15 foot wide bat wing mower is essential, and one of the two smaller bush hogs is necessary as well to get to the few places that are a bit too tight or awkward for the big bush hog. We have an 8 foot as well as a 4 foot bush hog for the tighter areas. We really only need one of the two smaller ones, and I'm not sure which Jason would pick if he were choosing between the two. The bigger tractor was about $50,000 when purchased, and the big bushhog was about $20,000. Between one tractor and one mower that is $70,000 in equipment for maintaining the free grass.  We also have a 500 gallon sprayer used for weed control and chain harrows used for dragging the pastures. 

And just like any other piece of equipment this stuff all has to be maintained, belts and chains have to be replaced, tires have to be replaced, fluids need to be changed, they run on that free diesel fuel, etc. Then you need a place to park this free equipment. The best part is that the free equipment runs itself. There is no manpower at all involved in servicing and maintaining it, much less hooking it up and mowing over 150 acres. I'm sure Jason is having a good laugh over that right now. 

The next expense in your free grass is keeping it looking nice and keeping it at optimum nutritional levels. This means we take multiple soil samples from all over the farm and have it analyzed on a regular basis. From these results we determine when to lime and when to fertilize. We fertilize at least once a year, sometimes twice. Lime is not applied yearly but every few years depending on soil tests. Each round of lime and fertilizer costs a few thousand dollars. It isn't necessary to do either of these and grass will still grow, but if you want the grass to have optimum nutritional value then you need to help out. We also re-seed various areas depending on need each year. Grass seed if of course free at as well, if you drive up to the co-op and ask for 100 bags of grass seed they load it in your truck and never expect you to actually pay for it.

Allowing horses to continuously graze pastures is incredibly hard on grass. Horses are pasture destroyers by nature. They do not graze evenly and are terrible spot grazers because they can thanks to their two rows of teeth. They like to return to the same place and over and wreck them, using their top and bottom teeth (many other grazing species don't have two rows of teeth) to eat the grass down to the ground. We do our best to mitigate their damage by re-seeding, liming, fertilizing, mowing and controlling weeds. Not to mention when it is really wet and they decide to gallop through the pastures, seriously damaging the free grass with every step. Throwing in the sliding stop, especially when wet, is just the icing on the cake for pasture damage.  

The hardest part to take with all of this free grass is when the weather thwarts all of your efforts anyway. We had a record breaking drought seven years ago that did serious damage to our pastures. It took about three years of intensive inputs and management to recover from that record breaking drought. I would be absolutely fine if we never experienced a drought like that again. As a general rule I find participating in record-setting weather events to be unpleasant experiences. I will never forget the defeated feeling I had while looking at our brown and yellow pastures that we had put so much time and money into.

Grass can be done much more inexpensively. It does not have to be mowed, fertilized, limed, have weed control,  be re-seeded, or anything else. You can put up cheap barb wire to fence in your grass. However, if you want to have pastures that look decent, and ours look at least decent most of the time, and have horses living on them year round, grass is expensive in money and time. 

To summarize it would be a lot cheaper to have much smaller pastures and allow the horses to over-graze them and feed hay year round. MUCH cheaper. So the next time any of you are talking to any farm owner, please skip the comment about how the grass is free. 

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Stormy and Rocky

Clayton, Walon and Johnny

Maisie and Lily

Renny, Dutch and Murphy wandering in for breakfast

B-Rad, Alex and Mick

Rip, Grand (sticking his tongue out), Elfin, Ritchie and Tony (Apollo is hiding behind Ritchie and Tony)

Romeo, Lotus and Donneur

Trigger having a stressful morning

Leo and Chance

Homer, Tony and Baby dozing in the shade

Fly Control

We frequently get asked about what we do for fly control. We try to take a multi-faceted approach and do things that actually work versus doing things that don't really have much effect. As an example I don't consider daily fly spray a very useful form of fly control. I've tried every fly spray on the market, from the all natural ones to Pyranha. I've even tried making my own fly spray using essential oils. The bottom line is they're all largely worthless. 

Sure, I'll use some fly spray when a horse is seeing the vet or farrier and is doing a lot of tail swishing, or I'll put fly spray on before I ride my horse.  I have one horse that I'm spraying daily as they are currently something of a fly magnet due to a health issue. It doesn't help the horse for long but it makes me feel better. But by and large I find fly sprays mostly useless. All of those claims the various fly sprays make about how many hours they last? What a joke. At best you get thirty minutes, maybe an hour with the Pyranha, of reasonable usefulness from any of them. I haven't found any sprays that deter ticks. I've tried Spot-On on many horses as I've often heard it is good for keeping ticks off. I can't say that I found that claim to be true in my trials. 

I think the Pyranha works the best out of any of the sprays (which still doesn't mean I think it has any long lasting effects). However I've seen enough horses have irritated skin from Pyranha that I don't keep it on the farm anymore. Plus, I'll admit I don't like pumping a bunch of insecticide into the environment, or inadvertently on myself. I find it ironic that some horse people will talk about all the horrible environmental damage farmers do using chemicals on their crops as they buy gallon after gallon of insecticide. Double standard much?

So outside of situation-specific uses I don't consider fly spray a very useful tool for fighting flies. In my view the more flies I can keep from reproducing, the better. The three main lines of defense I use against flies are fly predators, large biting fly traps, and small sticky traps.

The fly predators only work against certain types of flies and it is important that they be spread in the appropriate locations. We started using fly predators 3 or 4 years ago and saw enough of a difference from the fly predators that we are still using them a few years later. We order ours from Spalding.

We also use large fly traps that are designed to attract biting flies like horse flies and deer flies. We use the Horse Pal trap that can be found at www.bitingflies.com. We started with just one trap to see if it actually trapped any flies. It did, and now we have four traps around the farm. I'll probably add another one next year. The first couple of years we trapped a lot more flies than we do now. Between the fly predators, the Horse Pal traps, and sticky traps we've put a pretty decent dent in our fly population so we simply don't have as many flies to trap from year to year. That being said I don't think it is possible to ever trap too many flies, so much to Jason's chagrin he'll probably be assembling his fifth Horse Pal fly trap next year.

Horse Pal fly trap

The Horse Pal trap works by using a large target, a swinging black ball, to attract the flies. Then the trap takes advantage of a the natural response from these flies which is to continue to go up. The flies eventually wind up in a plastic jar at the top of the trap where they are killed by heat build-up in the jar.  We've found that the key to these traps is placement, just as described on the website. They need to be placed in an area that is open and in the sun all day for maximum effectiveness. We use a strand of electric tape around the traps to keep the horses from bothering them.

In addition to the large fly traps I also use sticky traps as well. I hang these down low, about 3 - 4 feet (about a meter), off the ground.  I was a little skeptical about these so I only bought two first and hung them up to see what would happen.  One fly buzzed over and got stuck to one as I was hanging the first one up, and they continued to get covered up with flies over a period of a couple of weeks. Now I order a dozen at a time and hang them up in various places around the farm. I change them out and put new ones up about once a month. I have a sick side that enjoys watching the traps fill up with flies. I check them almost every day to see how many more flies have been trapped, and I do the same with the Horse Pal traps. I know, there's something a bit off about that.

one of the sticky traps

I like that the fly predators, Horse Pal traps and sticky traps are on the job 24/7. I like that they don't involve spraying gallon after gallon of insecticide that has a very short window of usefulness into the environment. And I like that every fly I keep from producing means I have made a tiny but permanent dent in the fly population. I read somewhere that one female fly can produce up to 900 flies. I don't know where the term breeding like rabbits came from, it needs to be breeding like flies. 

Of course there are other things that play a role in fly control as well, with manure management being a big one. We do a lot of composting and harrow as appropriate as well.  Mitigating, and when possible eliminating, areas of standing water is also important. However there will always be flies around, and of course depending on what your neighbors are doing or not doing you may have to deal with their flies as well. 

There is no 100% perfect solution, but this approach seems to work the best for us. 

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Kennedy's typical look when he's napping

B-Rad and Alex

Johnny, Sam and Sebastian

Silky looking sleepy

a happy turkey family

George and Asterik

Cocomo and Gus

Romeo and Lotus

Remmy

Slinky and Lightning

River and Rocky

Jason's early morning view from the tractor

some of my early morning views the last couple of days