March 2008 Newsletter

[Clair Thunes]

Hello everyone,

A very happy belated New Year to you all. For those of you in
Northern California I am sure you love the beautiful weather we are
having after the heavy rain. I hope that with some extra hay your
horses are coming out of the amazingly wet weather ok. I recently saw
my first case of what looked like cellulites (inflammation of the
connective tissue under the skin). It is very common at this time of
year along with scratches. A wonderful vet once shared a cheap way of
dealing with scratches which is to make up a 50:50 solution of
betadine (solution not scrub) and witch hazel and dab it on the
scratches scabs. The betadine is antibiotic and she said that the
witch hazel has anti-fungal properties and dries the scabs out.
Eventually, after about a week, they fall off. This worked a treat
with the mare I had at the time after a nasty bought of cellulitis
resulting from a scratches scab. Another thing to consider in this
weather is the practice of washing muddy legs. While it is temping to
wash off the mud to make picking feet less mucky I do know of a horse
whose legs got chapped from such daily washing. He ended up with a
terrible case of cellulitis resulting from an opening on the back of
his pastern where his skin chapped from the constant wetting and
drying. The water and mud on an unclipped horse's leg drip off the
back of the fetlock and the oils in the coat provide a surprising
barrier. However I'm not sure they can cope with the power of the
water coming out of a hose. So I would steer clear of washings legs
on a regular basis unless it is absolutely necessary.

Getting back to nutrition. Recently a client informed me that the
product we have her horse eating was contaminated with whole grain.
Luckily this was easy for her to spot as it is supposed to be a
pelleted product so flakes of corn and oats were rather obvious.
Many of the mills that produce our horse feeds also produce many other
livestock products or even just different types of horse feeds, so
this kind of contamination does occur. For your average horse it
isn't a huge deal but for a horse with a condition that requires it to
have limited starch intake this kind of error could have disastrous
effects. So I encourage all of you to really look at the product that
comes out of every feed bag, especially if you are feeding a textured
feed that has a mix of grain and pellets etc you need to really look
to see anything unusual. If you think you see anything unusual check
the list of ingredients on the food label (see further down this
newsletter) and see whether the thing you think you see is listed. If
that doesn't help but your still concerned call the mill (address and
phone number on label) and ask if there was any change in the make-up
of your feed that you are not aware of as sometimes formulations
change. If the bottom line is that you think there is really
something not right, take the empty bag and some of the product back
to the feedstore and they should replace it. If they won't, call the
feed company (contact info also on bag) and they will take care of it
for you. I would recommend you open the 2nd bag at the store or ask
for a bag from a different batch to be sure multiple bags were not
affected.

If you have nutrition topics that you would like covered you are more
than welcome to send me suggestions by email at
in...@equilibrateequine.com or via the comment section at my website
www.eqiulibrateequine.com
Clair
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IN THIS ISSUE:
What is an essential amino acid?
Feeding the last trimester mare.
What is in a feed label?
First in a series looking at the equine digestive tract: From mouth to
stomach.
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WHAT IS AN ESSENTIAL AMINO ACID?
Proteins are made up of building blocks called amino acids. The
sequence of these amino acids determines what the protein is. It
should be noted that while we think mostly of protein as muscle
protein, enzymes, DNA, many hormones, and cytokines are also
proteins. The name amino acid comes from the fact that every amino
acid is made up of an amino group (two hydrogen's and a nitrogen) and
a carboxylic acid group (a carbon, two oxygen's and a hydrogen) along
with another carbon and hydrogen in and a side chain. There are many
different amino acids and the difference between them is in the side
chain.

Digestion of protein in our horse's digestive tract starts in the
stomach where pepsinogen is secreted and turned into pepsin. The
pepsin works to break the protein into it peptides which are very
short chains of amino acids which pass into the small intestine. Here
the peptides are broken down further into the constituent amino acids
by trypsin which is secreted by the pancreas. It is these amino acids
which are absorbed across the intestinal wall and into the blood
stream. Some small peptides, 2 or 3 amino acids, may also absorbed.
The amino acids are later reassembled into proteins.

The horse can also manufacture some amino acids by either altering the
side chain or by taking the nitrogen containing amino group and
attaching it to another carbon skeleton. However this process is not
possible in every instance and some amino acids must therefore be
provided in the diet. These are called essential amino acids, it is
essential that they be provided in the diet, and probably the most
commonly advertized are lysine and methionine. Next time I'll
discuss protein quality and limiting amino acids.

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FEEDING THE THIRD TRIMESTER MARE

Up until the last trimester providing they are in good weight and not
working, most broodmares can be fed as a horse at maintenance. At
about the 9th month of gestation the fetus weighs approximately 55% of
its final birth weight; this means it has to gain 45% of its final
birth weight in just 3 months. This rapid growth rate results in the
mare having a higher nutrient requirement during this time. Mares who
do not receive the necessary nutrient requirements during this time
may foal late in an attempt to have their foals be at the correct
weight at foaling.
From conception to the 8th month the 500kg mare's digestible energy
requirement increases from 16.7 to 18.5 Mcal per day as per the
national research council's (NRC) guidelines, which is an average
energy requirement of 17.2 Mcal per day. In their 9th month mares
will require about 10% more digestible energy as compared to the
average energy they required through to their 8th month. In the 10th
month this increases another 5% and again another 5% in their 11th
month. While it can be tempting to meet this increased energy
requirement by feeding more hay it should be considered that as the
fetus grows the amount of space within the body cavity for the
digestive tract becomes proportionally less. Your broodmare may not
be physically able to eat the amount of hay that would be required to
meet her energy requirement. Therefore it may be necessary to
consider feeding a feed which is more energy dense pound for pound
than hay. The benefit of starting this before foaling is that the
mare will have adjusted to this type of diet before foaling and the
very demanding metabolic state of lactation. In the last month of
gestation the 500kg mare requires 21.4 Mcal per day which increases to
31.7 Mcal in the first month of lactation!

Protein is needed to increase lean body mass so it comes as no
surprise that the mare's protein requirement increases during the last
trimester. Interestingly there have been studies showing that feeding
diets deficient in protein may lead to a slower return to ovulation
possibly due to lower progesterone concentrations post foaling. This
is an important consideration if you are planning on re-breeding your
mare. In early pregnancy low protein levels have been linked to lost
weight and early fetal loss. However, the 500kg mare (actually
estimated to weigh about 534kg by the 9th month) only requires 797g of
protein a day. If she is being fed 1.5% of her body weight per day as
grass hay (just over 17.5 lbs of hay) with a crude protein level of
10% she is receiving 801g of protein, enough to meet her requirement.
This requirement increases to 893g at 11 months and if we assume that
she does not eat any greater amount of grass hay then she would need
some protein supplementation from some other source. A lot of people
feed their broodmares some alfalfa for this reason. If the grass hay
intake of our 500kg mare was reduced to just over 14 lbs and just over
3 lbs of a 18% crude protein alfalfa was fed the total crude protein
intake would be 920g exceeding the 11th month requirement. It is a
common misconception that broodmares require a far greater amount of
protein than they actually do. If you are feeding a concentrate as
part of the diet in order to meet energy requirements a feed with a
12-14% crude protein level should be sufficient. Hay is generally
thought of as a low quality protein source containing fewer of the
essential amino acids (see above section) per unit mass. Therefore to
meet the horse's essential amino acid requirement a greater amount of
crude protein needs to be eaten. As eating more hay may not be
possible, feeding a supplement or concentrate that provides essential
amino acids may be necessary.

Interestingly several of the mineral and trace mineral requirements
are the same throughout gestation as they are for that same horse at
maintenance. This is the case for zinc, selenium, manganese, cobalt
and sulfur. Chlorine, copper, iodine, iron, sodium, potassium,
magnesium, phosphorous and calcium all have an increased requirement
for the last trimester. Most hays are high in iron and potassium and
the majority of horses are having their requirements met in excess so
adding these nutrients to the diet as a supplement is typically not
necessary. Copper and zinc tend to be low in most hays and it isn't
unusual for a typical diet to be deficient in one or both of these.
Alternatively, the diet may be so high in iron that the iron out
competes the copper and zinc for absorption leading to copper and zinc
deficiencies even though there may be enough copper and zinc present
in the diet. Therefore it is a good idea to provide a supplement that
will provide additional copper and zinc. This is particularly
important for last trimester mares because copper is required for
elastic connective tissue and collagen formation the main component of
the bone matrix. There has been research that suggests that foals
born to mares that were given supplemental copper had lower incidents
of osteochondrosis even if the foals were given supplemental copper
after birth. Look for a supplement that is made specifically for
pregnant mares and preferably one that says it will balance the type
of hay you are feeding.

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WHAT IS IN A FEED LABEL?

I am a sucker for nice packaging and so I know how easy it is to be
attracted to the images we see in magazine ads and on the side of feed
bags and supplement containers. Beautiful horses with flowing manes
running and jumping high fences, looking vibrant and healthy,
everything we wish for our horses we see depicted in these images.
And then when we read the text there are the apparent promises of
perfect black coats, great hooves, safe energy, it doesn't get any
better. But what are the ingredients in this product? How much fiber
is in it? Who makes it? Who do you call if you have questions or
concerns?

The uniform state feed bill developed by the Association of American
Feed Control Officials (AAFCO) and American Feed Industry Association
requires that all commercial feedstuffs have a label. In bagged feeds
this is a label that is sewn into one of the bags seams and in
supplements it tends to be stuck on the side of the container. The
label contains everything that you need to know about that feed.
The label is required to contain the following information; product
name, manufacturer, purpose statement and feeding directions,
guaranteed analysis, feed ingredients, net weight, precautionary
statements, active drug ingredients, company's name and mailing
address.
There is a lot in a name, Strategy, Ultium, Envision they are all
catchy and play a part in our decision to buy the product. Sometimes
there is a number associated with the feeds name for example "Winners
12". The number 12 in this name relates to the amount of crude
protein that is in the feed. I have seen feeds with two numbers in
the name the first of which was protein and the second fat, however I
am not aware of any regulations regarding a 2nd number only that
numbers must relate to protein content.

The label must state the net quantity of product. This is perhaps
particularly important when buying supplements which may appear to
have similar sized containers but contain different quantities of
supplement. If you are trying to shop economically and select
products based on cost this is worth looking at along with the amount
of supplement/feed required to be fed every day to meet the
manufactures suggested daily intake. The feeding guidelines must also
be on the label and on feed sacks are normally stated as the number of
pounds of feed required per 100 lbs of body weight. What the feed
label does not tell you is that if you feed less than this recommended
amount your horse is not guaranteed the balanced diet that the bag may
claim to provide. By which I mean if the feed states that feeding
this product will provide all the nutrients your horse needs if fed in
combination with a certain amount of a certain type of hay, this is
only true if you feed it at the levels specified. So if it says to
feed 1 lb per 100 lb body weight then you would need to feed your 1000
lb horse 10lbs of this feed per day to fulfill the nutrient gap. Very
few people actually feed the manufactures recommended amounts because
they feel that feeding that amount would make their horse fat or too
excitable. This is fine but be aware that your horse may not be
getting their entire nutrient requirements met if you feed this way.

The manufacturers name and address are required to be on the label.
The statement starting "manufactured by..." identifies the party
responsible for the quality and safety of the product and its
location. If the label says "manufactured for..." or "distributed by...."
Then the food was manufactured by an outside source but the name on
the label still designates the responsible party. There may also be a
contact phone number. If you have questions or concerns about any
product do not hesitate to contact the party given on the feed label.
This is how we dealt with the feed contamination issue I discussed
earlier and the feed company was very pleased to know they had a
quality control problem and provided the client with a free bag of
feed.

At the very least, the label must give the minimum percentages of
crude protein and fat and maximum percentages of crude fiber. These
are part of the guaranteed analysis. The term "crude" refers to the
methods used to test the product, these are rough estimates of
nutrient content. Amounts of other nutrients may also be given for
example ash (total mineral content) calcium, phosphorous and some
vitamins. Traditionally the percentages given on the label do
approximate the actual amount of that nutrient in that bag/container.
If the percent is a minimum for example 14% crude protein you can be
fairly sure that there will be slightly more than that in the feed for
example 14.3%. There will be enough to insure the manufacturer's
claims are met but not so much that unnecessary extra amounts of a
nutrient are being added. Generally speaking the percentage crude
fiber in a feed gives a rough idea of the feeds energy content.
Concentrate mixes with less than 6% crude fiber are dense in energy
and require careful management, with 8-12% crude fiber being a
moderate energy feed and 18% or over being relatively low. Note that
most senior complete feeds have high (approx. 18% or more) crude
fiber. This is because they aim to provide the fiber requirement for
horses unable to eat hay, these feeds have energy contents not
dissimilar to hay. If the calcium, phosphorous and salt in a feed
total 5.5% or higher of the total mix manufacturers are required to
give the minimum and maximum percent calcium, minimum percent
phosphorous and the minimum and maximum percent salt.

Under the guaranteed analysis is the ingredient list. Ingredients in
the product are required to be given in descending order of
predominance by weight. This means that there is more of the first
given ingredient than the second on a weight basis and so on down the
list. However there is a catch here in that the ingredients are
weighed in their "as fed" wet state. This means that they have not
been dried to remove the water content, and some feeds like molasses
are high in water content so the actual nutrients coming from that
feed will be less than other feeds further down the list. Generally
though it is safe to assume that the higher up the list the more of
that ingredient there is in the feed. This is very helpful if you
are trying to avoid certain ingredients. Some horses have food
allergies and so reading the feed label can be critical. However
there is catch. In order to keep costs down manufacturers sometimes
use collective feed names/terms. For example the ingredient list
might say grain product, which could be oats, corn, barley or rice, or
perhaps it says processed grain by-product which could be wheat bran,
rice bran, wheat mill run, brewers dried grains. The collective terms
are laid out by AAFCO and this allows feed companies to use which ever
product is available at a good price when that batch of feed is made
up and means they don't have to print new labels. They are able to
move with fluctuations in the market and as long as the guaranteed
analysis is met the ingredients can be manipulated. Whereas if the
ingredients state "oats" specifically they cannot use barley instead.
However, another caveat is that while an ingredient is listed it does
not have to be in the feed. So if it says oats and there are no oats
for a certain period of time the oats can be left out the label left
unchanged and as long as the guaranteed analysis can be met everything
is fine. This is great for the feed manufacturers but not so helpful
for horse owners who are trying to find out what exactly is in a
feed. My experience has been that the higher quality feeds use fewer
collective feed terms and while you will likely pay more for this feed
you will be more likely to know what is in it.

In the next newsletter I'll touch on some more labeling requirements
that are perhaps more pertinent to supplement labeling.

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FIRST IN A SERIES LOOKING AT THE EQUINE DIGESTIVE TRACT - FROM MOUTH
TO STOMACH

When I think of the equine digestive tract I am drawn to start at
the stomach and small intestine. The term suggests something internal
and yet we interact with the start of the equine digestive tract on a
daily basis every time you groom the very end of the muzzle or put on
a bridle with a bit. The digestive tract starts with the lips.
Horses have amazing lips, anyone who has watched a horse sort out some
component of a textured sweet feed knows just how dexterous they are.
If we picture a horse grazing we note that while eating the horse
walks very slowly, taking slow steps with its nose very close to the
ground and the lips are searching out food which is then gathered into
the mouth. The horse's front teeth are incisors just like ours and
they hold the chosen plants as the horse makes a small movement with
its head so as the plant breaks at the point where it is held by the
incisors. This activity goes on with the horse hardly lifting its
head. Saliva lubricates the plant material and the tongue moves the
material towards the back of the mouth where is it then chewed between
the molars before being swallowed. The horse's top jaw is wider than
the bottom and the chewing motion is from side-to-side and forward and
backwards, with each top tooth being ground down by the opposing lower
tooth and vice versa. Horse's teeth are very deep rooted and grow
very slowly over time. This concept is called Brachydonty. The
system works well except in some instances where the horse's diet may
not require much chewing resulting in less wear on the teeth, or a
tooth is lost so that the opposing tooth is not worn down. In
addition the outside edges of the top teeth and inside edges of the
lower teeth may not be adequately ground down during chewing resulting
in sharp "hooks". Any of these conditions may reduce a horse's
ability to adequately chew food and can be quite uncomfortable for the
horse and should be dealt with by an equine veterinarian or specialist
dentist. Depending on whether a horse has wolf teeth and canines it
will have either 36 or 44 teeth. Once food has been chewed the
particle size is reduced which increases its surface area. This is a
very important part of digestion as this process results in a greater
surface area on which enzymes and microorganisms can work. Part of
processing feeds is often to increase their surface area so that they
are more easily digestible.

As food is chewed saliva is released, approximately 10 to 12 liters a
day. While the saliva of some species contains large amounts of the
enzyme amylase which helps to start breaking down starch the amount in
equine saliva is not significant. However, equine saliva contains
large amounts of bicarbonate which acts to buffer stomach acid
lowering the acidity. The less a horse has to chew its food, the
lower the amount of saliva produced and therefore there is less
bicarbonate released to control stomach acid. This should be
considered before choosing to reduce long stem hay in the horse's diet
or any other feed that requires a large amount of chewing. In addition
there is the consideration that the longer a horse spends chewing
food the longer it's mind remains occupied and the lower the chances
of developing boredom related behavior issues.

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Services offered by Equilibrate Equine Consulting include phone
consultations on both nutrition and management issues, hay sampling
and interpretation, ration balancing, custom vitamin and mineral mixes
and packages for ongoing care. For more information please visit
www.equilibrateequine.com or email in...@equilibrateequine.com