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From: Terry S. Singeltary Sr. (216-119-144-9.ipset24.wt.net)
Subject: BSE Information- Using Dentition to Age Cattle
Date: January 1, 2005 at 2:35 pm PST

-------- Original Message --------
Subject: BSE Information- Using Dentition to Age Cattle
Date: Sat, 1 Jan 2005 14:59:39 -0600
From: "Terry S. Singeltary Sr."
Reply-To: Bovine Spongiform Encephalopathy
To: BSE-L@LISTSERV.KALIV.UNI-KARLSRUHE.DE


##################### Bovine Spongiform Encephalopathy #####################


BSE Information- Using Dentition to Age Cattle


For many years, producers, veterinarians, and exhibitors (at cattle
shows) have used cattle dentition to make general age determinations.
Dentition will vary from herd-to-herd and animal-to-animal, because of
the animal’s genetics, their diet, and the varied geographical locations
in which they are raised. Despite individual differences, when the age
of an animal is not known, examination of the teeth serves as the best
and most practical method of age determination. This document will serve
as FSIS guidance for aging cattle.

In order to age cattle using dentition, some background information is
necessary. This document will discuss and demonstrate: types of teeth
and their location in bovine jaws, deciduous incisors versus permanent
incisors, eruption times for deciduous and permanent teeth and using
eruption times of permanent incisors to age cattle.

Tooth types and location
There are three types of teeth found in the bovine: incisors, premolars
and molars. Incisor teeth are found in the rostral portion of the mouth,
but they are absent from the upper jaw. The premolars and molars (known
as cheek teeth) are found in the caudal part of the mouth and are
present in the upper (maxilla) and lower (mandible) jaws. The following
schematic (Figure 1) of the bovine skull, from an older animal (all
permanent teeth* are present), demonstrates the location of the teeth.

Figure 1

*At birth, calves have deciduous (temporary, milk, baby) teeth. The
deciduous teeth are lost as the animal ages and they are replaced by
the permanent teeth.

Deciduous (Temporary) Teeth
Calves have a total of 20 deciduous teeth. There are no deciduous molars
and deciduous premolar 1 is not present. The dental formula for the
deciduous teeth follows:

Deciduous teeth: 2(Di 0/4, Dc 0/0, Dp 3/3) = 20 deciduous teeth

The eruption of the deciduous teeth varies somewhat; about 75 percent of
the well-bred calves have all incisors erupted at birth. Average periods
of eruption of the deciduous teeth in cattle follow:

Table 1 – Eruption Times of Deciduous Teeth

Teeth

Age at eruption

First Incisor (Di* 1) Birth to 2 weeks of age.
Second Incisor (Di 2) “
Third Incisor (Di 3) “
Fourth Incisor (Di 4 or C) “
First Cheek Tooth (Dp* 2) Birth to a few days of age
Second Cheek Tooth (Dp 3) “
Third Cheek Tooth (Dp 4) “

* Di = deciduous incisor Dp = deciduous premolar


In photograph 1, the rostral view of a mandible from a young bovine
demonstrates the location of the different deciduous incisors; they are
identified – Di 1 through Di 4.

Photograph 1

photo1.jpg (46314 bytes)
Click on the
photograph for an enlarged image.

Permanent Teeth
Deciduous teeth are replaced by permanent teeth as the animal ages.
Premolar 1 is not present. The dental formula for the permanent teeth of
cattle follows

Permanent teeth: 2(I 0/4, C 0/0, P 3/3, M 3/3) = 32 permanent teeth

Average periods of eruption of the permanent teeth in cattle are found
in the following table:

Table 2 – Eruption Times of Permanent Teeth

Teeth

Age at eruption
First Incisor (I* 1) 18 – 24 months
Second Incisor (I 2) 24 – 30 months
Third Incisor (I 3) 36 months
Fourth Incisor (I 4 or C) 42 – 48 months
First Cheek Tooth (P* 2) 24 – 30 months
Second Cheek Tooth (P 3) 18 – 30 months
Third Cheek Tooth (P 4) 30 – 36 months
Fifth Cheek Tooth (M 2) 12 – 18 months
Sixth Cheek Tooth (M 3) 24 – 30 months

* I = Incisor P = Premolar M = Molar


The photograph (Photograph 2) below shows a mandible from a cow with all
of her permanent incisors present. The incisors are identified – I 1
through I 4.

Photograph 2

photo2.jpg (46523 bytes)
Click on the
photograph for an enlarged image.

Note:
In addition to the simple numerical designations for teeth, the
following terms are commonly applied to the individual incisors: central
(Di 1 or I 1), first intermediate or middle (Di 2 or I 2), second
intermediate or lateral (Di 3 or I 3), and corner incisors (Di 4 or I
4). Canine teeth are absent in cattle, unless the fourth incisor (I 4),
or corner incisor, is considered to be a canine tooth. If Di 4 or I 4 is
considered to be a canine tooth, then the dental formulas change,
slightly, to the following:

Deciduous formula: 2(Di 0/3, C 0/1, Dp 3/3) = 20 teeth

Permanent formula: 2(I 0/3, C 0/1, P 3/3, M 3/3) = 32 teeth

A dental formula is an abbreviated statement of the number and types of
teeth found on one side of the top and bottom jaw. Because the dentition
is the same on both sides of the jaw, the formula lists only one side,
and is enclosed in parentheses and multiplied by 2 to arrive at the
total number of teeth. Numbers above the lines are for the teeth located
in the upper jaw and those below the line are for the teeth in the lower
jaw.

Deciduous (temporary) incisors versus permanent incisors
The deciduous incisors differ from the permanent incisors in being much
smaller. The crowns (that part of the tooth that is covered with enamel)
of the deciduous incisors are narrower then the permanent incisors and
they diverge more from the base (at the gum line) of the tooth to the
apex when compared to the permanent incisors. Photograph 3 compares the
mandibles (lower jaws) from a young animal with deciduous incisors (red
arrow) to an older animal with permanent incisors (white arrow). The
difference in tooth size and shape and jaw width (and size) can be
appreciated.

Photograph 3

photo3.jpg (60152 bytes)
Click on the
photograph for an enlarged image.

Using teeth to age cattle
Cattle dentition is generally used as an indicator of age when actual
birthdates are not available. Eruption times and wear of the teeth are
the major factors used to estimate bovine age. This guidance document
will base the aging of cattle on the eruption times for the permanent
incisors.

The definition of eruption is the emergence/penetration/piercing of the
tooth/teeth through the gingiva (the gum line).

Eruption of teeth in cattle typically follows the pattern shown in the
Figures 2 - 7 below. The figures represent the incisor dentition from
young animals through animals that are 30 months of age or older.

An animal 14 months of age would have a full set of deciduous incisors
as shown in Figure 2. All four pairs of teeth are temporary and firmly
in place. The teeth are short, broad and usually have a bright, ivory
color. There is usually space between the Di 1 incisors. Other incisors
may touch on the inside corner at the top of the tooth. As the animal
ages, the deciduous teeth become loosely set in the jaw, especially the
central 2 incisors. The teeth appear longer and narrower (Figure 3) then
in younger animals and the teeth may or may not be touching at the upper
corners; an animal with this dentition is approximately 15 – 18 months
of age.


In Figure 4, a permanent central (I 1) incisor has erupted; temporary
incisors may or may not be present when the permanent incisor erupts.
The permanent incisors usually erupt at an angle (Figure 5) and
straighten into a definite pattern with growth. In Figure 5, both
central (I 1) incisors have erupted; they may or may not be in a
straight line with the inside corners touching. The central incisors, in
Figure 6, are in place, they have straightened and the inside corners
are in line. Animals with eruption of one or more central incisors are
considered to be 18 – 24 months of age. When one or both middle (I 2)
incisors erupt the animal is considered to be 24 – 30 months of age
(Figure 7).

The following sets of photographs will demonstrate the aging of cattle,
based on dentition, from 15 months to greater then 42 months of age.
These animals were aged using Table 1 and Table 2 above. The photographs
will show a rostral view and at least one rostrolateral view of each set
of teeth. (The following photographs are thumbnails, so please click on
them to get the enlarged image).

Cattle 15 – 18 Months of Age

The following four photographs show a rostral (Photograph 4a and 5a) and
rostrolateral (Photograph 4b and 5b)view of the dentition on the lower
jaw. All deciduous incisors are evident. These temporary teeth are often
loosely set in the jaw; especially the central incisors (Di 1). The
animals are approximately 15 - 18 months old. In photographs 5a and 5b,
the central incisors were very loose. Also, as described for Figure 2
above, the incisors are longer and narrower when compared to younger
animals.

photo4a.jpg (48220 bytes)
photo4b.jpg (50460
bytes) photo5a.jpg
(49680 bytes)
photo5b.jpg (45811 bytes)
Click on the
photograph for an enlarged image.

Cattle 18 – 24 Months of Age

The eruption of the first central incisor (or incisors) indicates that
the animal is in the age range of 18 – 24 months as indicated in Table 2
above. The Di 1 deciduous incisors may or may not be present when the
central incisors erupt.

The following three photographs show the eruption of the central (I 1)
permanent incisors; the deciduous incisors have been lost. One incisor
(white arrow), in photograph 6a, has recently erupted while the other
incisor (red arrow) has been exposed, due to the gingiva being
artificially torn during processing; this incisor had not penetrated the
gum line. Photograph 6c gives a better view of the erupted incisor
(white arrow).

photo6a.jpg (47849 bytes)
photo6b.jpg
(37451 bytes)
photo6c.jpg (34469 bytes)
Click on the
photograph for an enlarged image.

These photographs (7a and 7b) show that the central incisors (I 1) have
erupted and are fully developed, but are not in wear. The eruption of
the central incisors indicates that the animal is in the 18 - 24 month
age range. White arrows identify the central incisors in photograph 7a.

photo7a.jpg (40935 bytes)

photo7b.jpg (50127 bytes)

Click on the photograph for an enlarged image.

Photographs 8a and 8b show that the central incisors have erupted. These
incisors are fully developed. This animal is in the 18 - 24 month age
range.

photo8a.jpg (45572 bytes)

photo8b.jpg (62118 bytes)
Click
on the photograph for an enlarged image.

Cattle 24 – 30 Months of Age

Cattle that have the middle (I 2) incisor (or incisors) erupted are in
the 24 – 30 month age range as indicated by Table 2 above.

However, FSIS, as written in FSIS Notice 5-04, is using a conservative
approach and is determining that cattle with eruption of at least one of
the second set of permanent incisors (I 2) is 30 months of age or older.
FSIS would consider the animal in photographs 9a – 9c to be 30 months of
age or older; the animal in photographs 10a and 10b is also considered
to be 30 months of age or older.

These three photographs (9a – 9c) show the eruption of the middle (I 2)
incisors. The white arrows in photograph 9a locate the I 2 incisors; the
central (I 1) incisors (found between
the I 2 incisors) have erupted and are fully developed. Photographs 9b
and 9c are rostro- lateral views of the lower jaw. These photographs
demonstrate the variation in eruption of the I 2 incisors. The I 2
incisor (white arrow) in photograph 9c has recently erupted.

photo9a.jpg (59592 bytes)

photo9b.jpg (63594 bytes)

photo9c.jpg (58222 bytes)
Click on
the photograph for an enlarged image.

In photographs 10a and 10b, the central (I 1) and middle (I 2) set of
incisors have erupted.
The I 1 incisors are identified by the white arrows and I 2 incisors by
the red arrows in photographs 10a and 10b.

photo10a.jpg (46793 bytes)
photo10b.jpg
(47782 bytes)

Click on the photograph for an enlarged image.

Cattle Greater Than 30 Months of Age

The eruption of the lateral (I 3 or second intermediate) incisor (or
incisors) indicates that the animal has reached 36 months of age. The
eruption of the corner (I 4) incisor (or incisors) indicates that the
animal has reached at least 42 months of age. These ages are based upon
permanent incisor eruption times found in Table 2 above.

The following 4 sets of photographs are representative of animals that
are at least 42 months of age or older. These photographs (as you move
from Photograph 11 through 14) also demonstrate that as cattle age the
teeth are worn down. Photographs 14a and 14b demonstrate what happens
after years of use; the teeth have worn down to what are called “peg
teeth”.

photo11a.jpg (71543 bytes)
photo11b.jpg
(73060 bytes)
photo12a.jpg (75838 bytes)
photo12b.jpg
(66678 bytes)
photo13a.jpg
(67612 bytes)
photo13b.jpg (69217 bytes)
photo14a.jpg
(68692 bytes)
photo14b.jpg (55687 bytes)

Click on the
photograph for an enlarged image.

References

# Sisson, S and Grossman, J. D. The Anatomy of Domestic Animals.
4th edition, 1953. W. B. Saunders, Philadelphia .

# Getty, R. Sisson and Grossman’s: The Anatomy of the Domestic
Animals. 5th edition, 1975. W. B. Saunders, Philadelphia .

# http://edis.ifas.ufl.edu/AN046

# Nickel, R, Schummer, A, Seiferle, E and W O Sack. The Viscera
of the Domestic Animals. 1973, Springer-Verlag , New York .

# http://www.tnbeefcattleinitiative.org/shirtpocketinfosheets/sp11.pdf

# The Stockman’s Handbook. 6th Edition by M. E. Ensminger,
Copyright 1983 by Interstate Printers and Publishers.

http://www.fsis.usda.gov/ofo/tsc/bse_information.htm


######### https://listserv.kaliv.uni-karlsruhe.de/warc/bse-l.html ##########





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