Palatability in horse feeds

Lemon oil at extremely low levels is found to greatly enhance the palatability of even an extruded horse ration.

BACKGROUND OF THE INVENTION 
This invention relates generally to horse feeds and feeding but more 
specifically to improved palatability in horse feeds. 
High performance horses such as show or exhibition horses, harness horses 
and especially race horses pose especially vexing problems for their 
owners and trainers. For example, it has been found to cost an average of 
$5,100 to produce and raise a race horse to two years of age, plus an 
additional $3,400 to keep him in training the first year. Thus, when a 
race horse fails to perform, following one year in training and on the 
track, an investment of $8,500 in addition to the cost of the horse is 
involved. Obviously, the stakes are high to keep him sound and running. 
Although some unsoundness may be inherited, others may be due to accident 
and injury and still others may be due to subjecting to stress and strain 
beyond the capabilities of even the best structure and tissue, it has been 
determined that nutritional deficiencies have been considered a problem. 
Oftentimes, in spite of the nutritional balance of the ration and even in 
spite of tailoring a particular horse's feed to his individual nutritive 
requirements, many high performance horses will still be "hard keepers." 
That is, the animals will not consume a nutritionally adequate amount 
within the specified time for feeding. 
Accordingly, flavoring aids and palatability enhancers have gained wide 
acceptance in the industry. Although many such additives are available all 
are not effective for every horse under every condition. For example, 
prior art flavoring additives such as anise or licorice root, anise oil, 
monosodium glutamate, ginger, vanillin and molasses have been employed. 
Molasses (beet and cane variety) which is used most commonly is relished 
by most horses. It is used either diluted or undiluted on grain or hay. 
Additionally, few if any of the flavoring additives have been found to 
improve the palatability of the extruded high performance horse feed 
described in U.S. Pat. No. 3,946,115 which is highly palatable in its own 
right. Nevertheless, there is a need for an even more palatable feed, and 
there is an ongoing need for new and untested flavoring aids which might 
be effective where others fail. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a more palatable feed 
for the "hard keepers." 
It is a further object of this invention to provide a flavoring agent to 
satisfy the ongoing search for uniquely palatable feeds that will be 
consumed readily by even the most difficult of horses in the most 
difficult situations and yet which could be applied in practical amounts 
which would not distort the nutritional balance of the ration. 
A horse feed, especially an extruded feed containing lemon oil in an amount 
less than 0.01% by weight of the feed will fulfill the objects of this 
invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In accordance with the present invention, lemon oil when added to all 
classifications of horse feeds will result in improved palatability. The 
feeds are generally indexed according to the percentage of total 
digestible nutrients such as carbohydrates, fats and proteins. 
Accordingly, the feeds of this invention will include, for example, 
concentrates which contain at least 65% total digestible nutrients but are 
low in fiber (less than 10%), and roughage which is low in total 
digestible nutrients but proportionately high in fiber. The concentrates 
may be carbonaceous concentrates which are low in protein but high in 
energy value or the concentrates may be protein supplements which as the 
name implies are higher in protein. 
Cereal grains such as oats, corn, barley, grain sorghum, wheat and rye are 
commonly used as carbonaceous supplements while beet pulp, molasses and 
wheat bran may be employed in varying amounts to provide higher energy 
values. The protein supplements may be derived from legume seeds such as 
soybeans and field peas or from by-product sources such as linseed oil 
meal, cottonseed meal, soybean meal and corn gluten feed and meal. 
In the preparation of conventional horse rations the feed ingredients are 
milled, blended and pressed into pellets through for example, a pellet 
mill. For such rations the lemon oil may be coated over the exterior of 
the pellets, however, it is preferred for purposes of handling and 
effectiveness that the lemon oil be blended with the remainder of the 
ingredients. When applied on the inside of the ration the amount of lemon 
oil should be between about 0.01% and 0.001%, by weight of the ration, 
preferably 0.003%. The lemon oil should be a feed-grade suitable for 
horses and commercially available from a number of sources. 
Extruded Feed 
It is especially preferred that an extruded ration be utilized containing 
less than 0.01% lemon oil. Preferably, lemon oil at 0.0003% by weight of 
ration is admixed in the oil coating later described and coated onto the 
ration. 
Generally, a feed is produced from particular farinaceous, proteinaceous 
and fibrous sources with additional vitamin and mineral supplements as 
needed to make the feed nutritionally complete. The product is highly 
palatable and nutritionally superior either when fed alone or when fed 
mixed with other feeds. 
The farinaceous components of the present invention are preferably corn, 
wheat, flour, wheat meal by-products, wheat and wheat middlings. In spite 
of the long felt belief and conventional practice of utilizing oats as the 
primary or preferred grain source of starch for horses, it has been 
discovered that oats are not necessary nor preferred for purposes of 
extruded rations. The underlying reason for this is not precisely 
understood. In the present invention, even though corn and wheat are 
ordinarily less palatable to horses than oats in an unprocessed feed, the 
corn, wheat and wheat middlings when processed are significantly more 
palatable than are oats when processed by extrusion. The total amount of 
the farinaceous material of this extruded ration ranges from 35 to about 
65% by weight based on the overall weight of the final product. However, 
it is preferred to use from 40 to 50%. 
The proteinaceous material needs to be a source of high quality protein. 
One might expect that, by virtue of the horse's ability to manufacture 
some good quality protein in its caecum or large intestine, the horse has 
no particular need for additional high quality protein nor for well 
processed extruded feed. But this is not the case. The source of protein 
is critical in accomplishing the advantages of an extruded feed. Examples 
of suitable proteinaceous materials are legume seed meals such as soybean 
meal, soy flour, peanut meal, rapeseed meal, cottonseed meal, safflower 
seed meal and mixtures thereof. Meat and fish scraps, although high in 
protein and frequently used in other extruded feeds, have no utility in 
the applicants' formulation. Their palatability to horses is low in the 
extruded product. It is particularly preferred for convenience, economy 
and efficiency to utilize soybean meal as the proteinaceous material. The 
amount of proteinaceous material utilized is from about 10 to about 30% by 
weight of the final product and preferably from 20 to about 25%. 
The fibrous material is required in order to provide adequate structural 
strength or integrity to the final feed pellets and also to effect stool 
normality. Although oat hulls and alfalfa are conventionally utilized for 
their fiber in non-extruded horse feeds, such materials lack the requisite 
palatability for applicants' extruded feed. These materials cause a rough 
grainy or gritty surface texture in the pellets which is apparently 
offensive to horses. It is not understood why such effect is only 
prevalent in the extruded feed but the fact remains that it is. 
Accordingly, it has been unexpectedly discovered that soybean hulls, rice 
hulls and cottonseed hulls are the preferred fibrous material of the 
present invention in spite of their lower palability in non-extruded 
feeds. Soybean hulls are particularly preferred. The amount of fibrous 
material may be from about 5 to about 30% by weight of the final product; 
however, it is preferred to use 15%. 
The nutritional supplements of the present invention are the fat soluble 
and water soluble vitamins and minerals which are nutritionally 
advantageous to high performance horses. Typical ones are vitamins A, D, E 
and the B vitamins, riboflavin, niacin, thiamine, biotin, pantothenic, 
choline, pyridoxine, and also ascorbic acid and calcium, phosphorus, 
copper, iron, manganese, iodine, zinc, cobalt, salts such as sodium 
chloride and combinations thereof. The nutritional supplements are 
utilized in an overall amount of from about 3 to 4% by weight of the feed. 
In the process of making the extruded horse feed, the above-described 
farinaceous, proteinaceous, fibrous and nutritional ingredients are 
uniformly mixed and finely ground. The materials may be ground separately 
or they may be mixed prior to grinding. If desired, small amounts of 
vegetable oil (about 2%) can be added to soften the mixture for ease of 
working. After grinding, the mixture is introduced into a steam 
conditioning chamber at from about 85.degree. to about 98.degree. C. to 
bring the moisture content up to between about 25 to 35% by weight of the 
mixture. The damp mixture is formed, by minimal expansion extrusion, into 
relatively homogeneous feed particles. The conditions of forming are 
carefully controlled to produce feed particles having a bulk density of 
above 32 pounds per bushel but preferably from 35 to 42 pounds per bushel. 
The particles must also be formed in a manner which gives them a smooth 
texture with a minimum of torn or rough surface projections. The particles 
are formed into shapes which may have a length of from 1/8 inch to 3 
inches. Preferably, the particles should be formed into shapes having 
rounded edges, such as small cylinders or rounded ovals. The particular 
shapes should have mean statistical diameters between 0.15 and 0.6 inches. 
The statistical diameter of the particles is determined by the method of 
Martin and a mean is taken by analyzing a random sample of the product. 
(cf. Small Particles Statistics, G. Herdan and M. L. Smith, Chapter 5, 
pages 61-98.) A sufficiently large sample is taken so that the standard 
error of the mean is within .+-.0.01. 
The process of this aspect of the invention may be practiced on a 
conventional extrusion device. The rotating screw of the extruder device 
creates a high pressure on the material in the extruder. It is believed 
that the particulate material fed in changes form until it finally flows 
in a generally fluid manner, even squeezing around the outer periphery of 
the screw in a recirculating fashion, to cause a severe mechanical working 
of the substance. Part of the pressure is caused by the screw. Part of the 
pressure is due to the high temperatures which result both from friction 
between the flowing product and components of the extruder and from heat 
that it purposely added to the outside of the extruder, if under normal 
operation. This added heat is preferably obtained by passing steam and/or 
water through a forward or front annular jacket within the extruder 
housing around, but separate from, the forward end of the extruder 
chamber. Steam may also be added directly into the extruder to increase 
the temperature of the material and/or to raise the moisture content of 
the material, if desired. The amount of heat applied is controlled by 
typical valving techniques in a manner to obtain temperatures which are 
not sufficiently high so as to cause the product to scorch or burn, but 
which are sufficiently high to cause the desired chemical and physical 
reactions within the material. The amount of added heat to do this will 
vary with the particular extruder construction, but can be readily 
determined by trial and error during the initial stages of operation of 
the equipment. 
In addition to the steam jacket for adding heat, an annular cooling jacket 
surrounds the rear portion of the extruder chamber. This has been found 
desirable in normal operation to maintain lower temperatures in the 
initial stages of operation. 
The moisture content and grind of the damp material and the temperatures 
and pressures of extrusion must be selected in a manner to produce an 
extruded product which will have the desired properties. In particular, 
the bulk density of the extruded material must be above about 32 pounds 
per bushel, preferably about 35 to 42 pounds per bushel and most 
preferably 38 pounds per bushel after the product has been dried to a 
moisture content of about 10 to 12% by weight. 
The extrudate, after processing, forming and cutting, is then uniformly 
coated with vegetable oil to form the final product. In spite of the fact 
that hot liquid animal fat is ordinarily equivalent to vegetable oil as a 
coating on other extruded products, it has no utility in the applicants' 
extruded horse feed. Only vegetable oil is suitably palatable to horses as 
a coating on the applicants' extruded product. The explanation is not 
apparent at this time. The vegetable oils of the present invention are, 
for example, corn oil, soybean oil, safflower oil, cottonseed oil or 
peanut oil. Soybean oil is preferred. The oil is applied in an amount of 
from about 2% to about 10% by weight of the final product but preferably 
4%. The coating may be applied by spraying weighed batches or as part of a 
continuous process with any appropriate metering device. The spray 
coating, if desired, may be followed by or even substituted by a period of 
oil blending to insure uniformity. Spray coating is preferred. 
It is at this stage, the coating stage, of the extrusion process that the 
extra palatable lemon oil is employed. The lemon oil is preferably added 
into the coating oil prior to spraying the oil coating onto the feed. Good 
results may be achieved by adding less than 0.01% lemon oil by weight of 
the feed. The best results are achieved between 0.0001 and 0.001%. It is 
preferred that about 0.0003% lemon oil be utilized. 
The Application of Lemon Oil 
It is of note that the effectiveness of lemon oil does not necessarily vary 
in direct proportion to the amount. For example, in pelleted rations the 
horses were found to reject the ration if as much as 0.03% lemon oil was 
present. In the case of an extruded ration, although the horses preferred 
a ration containing 0.003% lemon oil over a ration which contained no 
lemon oil, the preference was even stronger at 0.0003%. 
The following examples will provide a detailed illustration of the 
objectives and embodiments of this invention: 
EXAMPLE 1 
An extruded ration was prepared containing a mixture of 32.5 parts corn, 10 
parts wheat, 10 parts wheat middlings, 15 parts soy hulls, 22.9 parts 
soybean meal and 3.6 parts vitamins and minerals. The mixture was finely 
ground and introduced into the steam conditioner of an extruder wherein 
30% moisture by weight was added to the mixture at about 85.degree. C. The 
mixture was then passed through an extruder at about 130.degree. C. having 
an oval shaped die adapted to provide particles measuring 3/8.times.1/4 
inches between diameters and resulting in a bulk density of 38 pounds per 
bushel. The product was dried to about 12% moisture by weight. The 6 parts 
soybean oil was uniformly sprayed onto the pellets. This ration was 
labeled the Control. 
A portion of the feed prepared above had 0.003% lemon oil by weight of the 
feed added to the soybean oil and the ration was labeled A. An identically 
prepared ration as A except containing only 0.0003% lemon oil in the 
soybean oil was labeled B. 
Six yearling quarter horses were each offered two bowls of ration of 
identical size during feeding periods over a five-day test. For three of 
the horses, one bowl contained the Control and the other contained ration 
A. For the other three horses the choice offered was between the Control 
and ration B. The daily consumption in pounds for each horse is listed in 
Tables I through VI. 
TABLE 1 
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Days/Ration Control A 
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1 3.3 10.1 
2 9.5 6.3 
3 7.3 5.5 
4 8.8 1.9 
5 5.1 6.1 
Total 34.0 29.9 
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TABLE II 
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Days/Ration Control A 
______________________________________ 
1 1.3 9.4 
2 2.6 7.7 
3 4.5 6.4 
4 3.7 9.1 
5 3.6 7.5 
Total 15.7 40.1 
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TABLE III 
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Days/Ration Control A 
______________________________________ 
1 6.1 3.9 
2 9.6 2.0 
3 6.3 6.3 
4 5.9 6.2 
5 3.8 6.8 
Total 31.7 25.2 
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Grand Total Control: 81.4 pounds 
Grand Total A: 95.2 pounds 
Grand Total Preferences of at least 1 lb./day for Control: 5 
Grand Total Preferences of at least 1 lb./day for A: 8 
Note that the horses consumed more of A than Control in total pounds and 
preferred A more often than the Control. The fact that two of the three 
horses consumed more Control than A is a bit misleading but the number of 
choices and the total consumption places heavier weight on the conclusion 
that A is more palatable than the Control. Tables IV through VI will 
provide more examples of preference. 
TABLE IV 
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Days/Ration Control B 
______________________________________ 
1 3.7 7.7 
2 1.9 11.8 
3 7.3 3.3 
4 3.5 9.3 
5 6.0 5.2 
Total 22.4 37.3 
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TABLE V 
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Days/Ration Control B 
______________________________________ 
1 1.6 9.4 
2 4.5 6.5 
3 4.7 9.2 
4 3.5 9.8 
5 1.6 11.1 
Total 15.9 46.0 
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TABLE VI 
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Days/Ration Control B 
______________________________________ 
1 1.2 9.5 
2 2.3 9.3 
3 0.4 11.4 
4 1.4 9.0 
5 2.1 9.2 
Total 7.4 48.4 
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Grand Total Consumption 
Control:--45.7 
B:--131.7 
grand Total of Preferences of at least 1 lb./day: 
Control:--1 
B:--13 
example 2 
a pelleted ration of Horse Chow from Ralston Purina was used. 
The pelleted feed without the lemon oil was labeled Basal while a pelleted 
ration of Horse Chow was prepared containing 0.03% lemon oil mixed in was 
labeled C, and one containing 0.003% lemon oil was labeled D. 
The feeding studies conducted were performed in an identical manner as 
those of Example 1 except more horses were used and each horse was tested 
over a longer period. 
Only the results of preferences of at least 1 pound per head per day are 
reported in Table VII. 
TABLE VII 
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Times Preferred Times No 
Basal Test Ration Preference 
______________________________________ 
C(0.03%) 164 7 4 
D(0.003%) 4 176 2 
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