W. J. (William J.) Miles.

Modern practical farriery : a complete system of the veterinary art as at present practised at the Royal Veterinary College, London online

. (page 152 of 160)
Online LibraryW. J. (William J.) MilesModern practical farriery : a complete system of the veterinary art as at present practised at the Royal Veterinary College, London → online text (page 152 of 160)
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is commonly supposed. I find in comparing Southdown
ewes with ram hoggets which have been bred and reared on
the same farm, that there is but very slight difierence in
favour of young rams."

At about one year and nine months, the second pair of
temporary incisors are replaced by permanent ones ; although
canes do occur in which these teeth are developed within one



year and six months from birth. In fact, this is the period
Professor Simonds gives as his early average ; but although
such is the case, on the other hand instances of later dentition
with these particular teeth sometimes come to our knowledge,
in which the second pair of deciduous teeth have been in the
mouth of an animal two years old. But we never have met with
them in the gums of sheep between two and three years of
age — the period assigned by Touatt for their fall, and six
months more for their full development, namely, when the
sheep has reached his third year. Simonds asserts, and such
is our experience, that one year and three quarters is the
average time when sheep will cut their second pair of per-
manent incisors. The third pair of incisors are replaced by
their successors when the sheep is two years and a half old ;
but instances are ot common occurrence in which, especially
among advanced breeds, these teeth are shed when the animal
has lived only two years and three months. This of course is
the early average, whereas the late average represents sheep
as not cutting the third pair of permanent incisors until six
months later, i.e., when the sheep is two years and nine months
old. The same latitude, or a period of six months, must
also be allowed in considering the time when the fourth pair
ot milk teeth make room for their succeeding ones ; the mean
average being when the sheep is three years and three months
old. Sometimes however, these teeth appear three months
earlier (the early average); at other times three months later
than the mean average, i.e., when the animal's life extends
to three years and six months. At the time the above
teeth are cut, the central and second pair of permanent
incisors will give indication of considerable wear, and not
uncommonly rise in their sockets to compensate for their
decreased height, which has been efi'ected by attrition. These
central teeth, also, are frequently broken whilst the sheep
is biting the wood of hard plants, which are constantly met
with on heath lands, &c. This gives to the mouth an old
appearance, and sheep with such injured teeth are often
said to be very old, and for this reason have been named
"crones " (old women), from the Greek word ■)(^p6voi, " time. "
In this consideration however, we are likely to be much mis-
taken, as this accident may occur, and sometimes does, before
the sheep is three years old. Such animals often lose con-
dition, and consequently require more care than those having
these teeth intact. " The Norfolk heath-land farmer has to
look well to his flock, and to draft such sheep. When removed
into other districts where they can live on good grass land
and have manger food, these animals, however, are profitable
for breeding purposes until they are ten, twelve, or fif-
teen years old, as we see in Leicestershfre and other counties.
There is this important difference, however, between the old
sheep of Leicestershire and the crones of Norfolk ; namely,
that in one instance the incisors have been gradually worn
down, while in the other they have been prematurely forced
out or broken oS'. A broken incisor often leads to the displace-
ment of other teeth. It will also occasionally lacerate the
dental pad, and not unfrequently works its way through the



THE DISEASES OF CATTLE, SHEEP, AND PIGS.



71



substance of the pad to the bone itself." From the foregoing
it will be understood, that when the sheep is three years and
six months old, the permanent dentition of this animal is
completed, although sometimes the process terminates three
mouths before, and at times three months, or more, later. After
this period therefore, our judgment in determining the age
of the sheep must be guided, first, hj the wear and tear of the
teeth, and secondly, by the general appearance of the animal.
Although as a rule, the sheep is full-mouthed when three years
and six months old, yet a few instances are not wanting in
which the corner temporary incisors are in the mouth at four
years ; but this is an exception to the rule, which seldom varies,
in that the sheep, before the expiration of the fourth year of
life, possesses all its permanent incisors and molars, and con-
sequently is full-mouthed.

THE AGE OF THE PIG AS INDICATED BY THE TEETH.

Correct information relative to the age of the pig as indi-
cated by the teeth, was never given to the public by Girard
or Youatt, although these writers were received as authorities
on this important matter for years previously to the appear-
ance of Professor Simonds' work " On the Age of the Pig."
Zouatt doubtless translated from Girard, and in so doing
repeated his errors, which a slight examination of the den-
tition of this animal would have prevented. In fact, he
copied without investigating the subject for himself, and con-
sequently we find Girard and Youatt writing in the self-same
strain; the latter repeating all the mistakes of the former.
" The hog," writes Youatt, " has fourteen molar teeth in each
jaw, six incisors and two canines ; these latter are curved
upwards, and commonly denominated tushes. The molar teeth
are all slightly difi'erent in structure, and increase in size from
first to last ; they bear no slight resemblance to those of the
human being. The incisors are so fantastic in form as to
baffle description, and their destined functions are by no
means clear. Those in the lower jaw are long, round, and
nearly straight; of those in the upper jaw, four closely
resemble the coiTesponding teeth in the horse, while the two
corner incisors bear something of the fleur de lis shape of
those of the dog. These latter are placed so near to the
tushes as often to obstruct their growth, and it is sometimes
necessary to draw them in order to relieve the animal and
enable him to feed.

" The calculation of the age of the hog by means of reference
to the mouth has not yet been carried beyond three years —
no writer seems to have gone much beyond the protrusion of
the adult middle teeth of the lower jaw. The hog is born
with two molars on each side of the jaw; by the time he is
three or four months old he is provided with his incisive milk
teeth and two tushes. The supernumerary molars protrude
between the fifth and seventh months, as does the first back
molar ; the second back molar is cut at the age of about ten
months, and the third generally not until the animal is three
years old. The upper comer teeth are shed at about six or
eight months, and the lower ones at about seven, nine, or ten



months old, and leplaced by permanent ones. The milk
tushes also are shed and replaced between six and ten months
old. The age of twenty months and from that to two years,
is denoted by the shedding and replacement of the middle
incisors or pincers in both jaws, and the formation of a black
circle at the base of each of the tushes. At about two years
and a half or three years of age the adult middle teeth in
both jaws protrude, and the pincers are becoming black and
roimded at the ends. After three years the age may be com-
puted by the growth of the tushes : at about four years, or
rather before, the upper tushes begin to raise the lip ; at five
they protrude through the lips ; at six years of age the tushes
of the lower jaw begin to show themselves out of the mouth
and assume a spiral form. These acquire a prodigious growth
in old animals, and particularly in uncastrated boars. As they
increase in size they become curved backwards and outwards,
and at length are so crooked as to interfere with the motion
of the jaws to such a degree that it is necessary to cut oflF these
projecting teeth, which is done with a file or with nippers."

The above contains the views of Youatt respecting the
development of the pig's teeth ; these views were considered
correct until Professor Simonds found that little reliance could
be placed on Youatt's assertions, and therefore determined to
study the teething of the pig " from the period of ita birth
onwards until the permanent set of teeth should be completed,
and to mark the changes these organs might undergo, depend-
ing on wear or increasing age."

The incisors of the pig difi"er in their external outline from
those of any other domesticated animals. Their formatioi^
and arrangement in the upper jaw difiers from that noticed in
the lower ; for instance, the fangs of the teeth fixed in the
sockets of the former take a curved course backwards and
inwards, and their crowns pass down into the mouth almost
vertically, i.e., at right angles to the lower jaw, from which
the incisor teeth common to it run out almost in the same
straight line with the jaw. Their fangs, also, slightly curve
backwards and upwards, but are much longer than the fangs
of the corresponding teeth in the upper jaw. The fangs, how-
ever, common to the upper teeth gradually decrease in length
from the middle to the comer ones, whereas the fangs of the
middle pair of the lower incisors are not quite so long nor
thick throughout their entire length as the lateral teeth situ-
ated next to them. These last-named teeth possess fangs more
than double the length of the comer incisors, which are in
every respect much smaDer teeth, both as regards their fangs
and crowns. The pig is bora with four teeth in each jaw, in
all eight ; and by taking one side of the lower jaw for
examination, we find one tooth in the place of the comer incisor,
and another in that of the tush. Simonds has named these
teeth, respectively, the foetal incisor and foetal tush, owiug to
the place they occupy in the mouth during ibetal lifp- The
situation of these at the sides of the mouth leaves a space
between them in the middle of the mouth, and consequently
the nipple of the sow can be brought into the young pig's
mouth through the space created between the eight teeth



72



THE DISEASES OF CATTLE, SHEEP, AND PIGS.



above mentioned. Moreover, the nipple of the sow ia yet
further protected from injury by the tongue of the sucking
pig, which in this act may always be seen surrounding and
firmly adhering to its mother's teat. This grasping power of
the tongue is greatly facilitated by the existence of a fringed
border which surrounds it when " in the act of sucking ; the
tongue is doubled along its middle, so that these fringes are
brought into such a position that they can partially overlap
the nipple, and thus produce the grasping power alluded to."
At one month old, four incisors being then situated in front of
the mouth, viz., the middle temporary teeth, two in the upper
and two in the lower jaw, appear in the gums, as also do the
two temporary molars, being the second and third in position.
The first or anterior deciduous molar sometimes is cut at the
expiration of the first month, but as a rule this tooth does not
make its appearance until five or six days later. The third
molar in the lower jaw presents a very similar configuration
to that noticed in the ox and sheep, described under their
respective headings as being composed of lobes and cusps,
and as occupying a much greater space both in diameter and
length than its two anterior companions. When the young
pig has reached the age of three months, four more temporary
incisors, the lateral teeth, issue from their sockets, and in
80 doing complete the temporary dentition of the pig,
both that of the incisors and that of the molars ; consequently,
before the pig is three months and a half old its mouth
exhibits (taking one side of a lower jaw for description) a
foetal tush, a foetal incisor occupying the situation of the
corner incisor of other animals, and two middle incisors and
two lateral ones; these last-named pairs occupying the
front part of the mouth. In addition to the above, three
temporary molars are situated anteriorily to the three per-
manent molars, which enter the jaw at a later period, after-
wards to be considered. From three months and a half to
six months, no new teeth escape into the mouth, neither does
any replacement of teeth occur. On the wearing surfaces of
the temporary teeth, however, signs of attrition indicate that
the pig is nearing the age of six months, soon after which
period, on each side of both jaws, just in front of the molars
and behind the fcetal tush in the lower, and directly in front
of the molars in the upper, two teeth are added to the
previously described set. These have been named by Professor
Simonds "Premolars," which appellation he has borrowed from
Professor Owen, but has mistaken the latter's reason for
naming certain teeth premolars. Simonds writes, " Professor
Owen has applied the term premolars to the teeth which
succeed the temporary or deciduous set of molars. He limits
the ordinary word molar to those teeth which are not preceded
hy similar ones. The term premolar therefore, is intended
to signify the pre-existence of other teeth in the situation of
these molars." Such is Professor Simonds' explanation of
the peculiarities of premolars; now the description given
of these teeth by Professor Owen leads me to believe that
by premolars he meant to signify that such teeth existed in
the jaw anteriorly to the permanent molars, and such would



be tne true meaning of the Latin preposition fprce, before,\,
4. fid not on account of such teeth being preceded by deciduous
ones. For instance, Professor Owen caUs the tooth now under
notice (the premolar of Simonds), the first premolar, and the
three molars situated posteriorly to it, respectively premolars
No. 2, No. 3, No. 4. Now, in further confirmation of my
view, it is known that the premolar of Simonds and the first
premolar of Owen is not a deciduous tooth ; it is never shed
to make room for a successor; consequently Owen would
not have called this tooth the first premolar, if he had
intended to convey the idea, that by premolar he meant to
signify the pre-existence of another tooth in the situation
of this molar. The word premolar is a very well applied
and distinctive term in describing the dentition of the pig,
especially so, as the terms temporary molars and permanent
molars in the present chapter have been used; and therefore
the first premolar of Owen can be called the premolar,
as no other tooth of this name has been mentioned in our
above nomenclature. In other animals, similar teeth to
the premolar of the pig exist. For instance, in the sheep
and ox these teeth are called supernumerary molars ; in the
horse they are named wolf's teeth. These teeth are permanent
ones, and consequently if removed by accident or as the
result of a surgical operation, are not renewed. At six months,
or soon after, the first permanent molar, viz., the fourth in
position, breaks through the gum. At from nine to ten
months the foetal incisor and the fcBtal tush are replaced by
permanent teeth ; these, it will be remembered, were existing
in the mouth at the period of birth, on each side of the jaws.
Just previously to the fall of these teeth, a slight inspection
of the mouth will demonstrate to how great an extent, during
the past nine months of life, they have been exposed to the
efi'ects of attrition, as they wiU appear nearly ground down
to a level with the gums. The tusk of the hog is the same
tooth as the canine of other animals, and holds in the mouth
a similar position. Professor Owen usually calls them canines,
and in describing their development in the wild boar, writes: —
" The upper canines in the wild boar curve forward, outward,
and upward, their sockets inclining in the same direction,
and being strengthened above by a ridge of bone which is
extraordinarily developed in the masked boar of Africa. The
enamel covering the convex inferior side of this tusk is longi-
tudinally ribbed, but is not limited to that part; a naiTow
strip of the same hard substance is laid upon the anterioi
part, and another upon the posterior concave angle forming
the point of the tusk, which is worn obliquely upward from
before, and backwards from that point. In the sow the
canines are much smaller than in the boar. Castration arrests
the development of the tusks in the male."

The lower tusks are much longer than the upper ones, and
take a direction upwards and backwards; their fimgs assume
a downward and backward course, but as age advances, they
become vertically disposed. From ten months we pass on
to twelve or thirteen months, at which period the middle
temporary incisors a'-e shed, and replaced by their permanenl




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THE DISEASES OF CATTLE, SHEEP, AND PIGS.



73



successors. The middle permanent incisors differ little from
their temporary forerunners. They are broader and flatter,
but their chief difference consists " in the existence on their
upper and inner surface, of a well-marked ridge running
parallel with their long axis, and bounded on either side by
a deepish hollow. In the recently cut incisor, these hollows
unite, at the apex of the tooth, giving a pointed extremity to
the ridge just described." The same remarks apply equally
to the middle permanent incisors, both of the upper and
lower jaws. At this period also it will be observed that the
corner incisors and tusks have considerably grown, the lower
tusks to nearly an inch long. Soon after the appearance of
the permanent middle incisors, the three anterior temporary
molars escape from the gums and are replaced by permanent
teeth; the two anterior teeth generally fall before the third,
and consequently their places are filled with permanent
molars. A short time before, a similar exchange is noticed in
the third molar, and that situated posteriorly to the second
(now) permanent double tooth. Before the pig has attained
the age of sixteen months, the permanent molars will be nearly
on the same level, the middle incisor will have become
almost fully developed, and the tusks also commence assum-
ing a circular course upwards and backwards. The only
temporary teeth now remaining in the mouth, it will be
recognized, are the lateral incisors; these, however, before the
animal is one year and seven months old, are replaced by
permanent teeth ; at the same period the last or sixth per-
manent molar makes its appearance, and before two months
have elapsed it will be on a level with the other double
teeth. The dentition of the pig is, as a rule, therefore
completed by the time the creature has lived one year
and seven months, and after this time its age must be
guessed at by its general appearance. In the boar, however,
the greater or lesser development of the tusks will afford
some guide in determining its age up to three or four years.
Professor Owen, in describing the molar dentition of the hog,
writes : — " The teeth of the molar series progressively increase
in size from first to last. The first premolar (the premolar of
Simonds), has a simple, compressed, conical crown, thickest
behind, and has two fangs. The second premolar (the first
molar of Simonds), has a broader crown, with a hind lobe
having a depression on its inner surface, and each fang be-
gins to be subdivided. The third premolar (second molar of
Simonds), has a similar but broader crown implanted by four
fangs. The fourth premolar (third molar of Simonds), has
two principal tubercles and some irregular vertical pits on
the inner half of the crown. The first true molar (fourth of
Simonds), when the permanent dentition is completed, exhibits
the effects of early development in a more marked degree
than in most other mammals, and in the wild boar has its
tubercles worn down, and a smooth field of dentine exposed
by the time the last molar has come into place. It originally
bears four primary cones with smaller subdivisions formed by
the wrinkled enamel, and an anterior and posterior ridge.
The four cones produced by the crucial impression, of which



the transverse part is the deepest, are repeated on the second
true molar (fifth of Simonds), with more complex shallow
divisions, and a larger tuberculate posterior ridge. The
greater extent of the last molar (third of Owen, sixth and
last of Simonds), is chiefly produced by the development of
the back ridge into a cluster of tubercles ; the four primary
cones being distinguishable on the anterior main body of the
tooth. The crowns of the lower molars are very similar to
those above, but are rather narrower, and the inner and outer
basal tubercles are much smaller, or are wanting.' The sixth
molar is, as stated by Owen, much larger than its tellows, and
consequently cannot be mistaken. It resembles aomewhat the
form of the third molar of the lower jaw, in that it possesses
three divisions, i.e., is trilobate; and that from each lobe two
cusps arise, which are intersected by small subdivisions. This
development is readily noticed on the newly cut tooth, but
in a short time daily attrition causes its obliteration.



THE PIG.

THE CONSTRUCTION OF PIGGERIL-b.

Nothing to those keeping or about to keep pigs can be
more important, if the well-being of these creatures is con-
sidered, than the selection of suitable ground whereon to build
proper habitations — " Principle sedes" porcis. Many persons,
in past years and even at the present time, think any hovel
is good enough for the pig's home, and that he delights to
wallow in his own mire. This is a most unfortunate mistake;
one that has retarded both the growth and fattening tendency
of such animals, and sometimes produced disease, and con-
sequently caused great loss to owners. The land suitable
for building piggeries on is not very different to that which
is required for other animals, viz., rising gi'ound from which
the drainage can flow naturally. The back of the sties, also,
should be so constructed as to afford shelter from the north
and east winds ; and if this arrangement be carried out, it is
obvious that the open parts and yards in front must face the
south or south-west ; it is also very important to insure
perfect ventilation. The above items mentioned aa being
necessary to the health of pigs, can with very little fore-
thought and expense be thoroughly and efiiciently obtained.
Having chosen a plot of rising ground, the extent of which
must of course be defined according to the size and number of
sties required, it will be our next endeavour *-> build the
dormitories and yard walls. It matters little of what material
these are composed, so long as they are impervious to wind
and weather (this remark particularly applies to the sleeping
compartments) ; but perhaps brick or stone, when these can be
readily and cheaply procured, recommend themselves more
particularly to our notice, as being likely to form the most
durable fabric. In order to explain the mode of constructing
piggeries and of keeping them clean, and of insuring easy
drainage and perfect viCtilation within them, it will be con-



74



THE DISEASES OF CATTLE, SHEEP, AND PIGS.



venient for the sake of plainness to describe the construc-
tion and the system of hygiene to be adapted to one. Given
then a plot of ground, as above described, sufficient to build
one sty upon. The walls composing the sleeping shed
should be built of brick or stone ; but if these materials are
not of easy access, then rough wood covered outaide by mud
walls will form a perfect protection against wind and bad
weather. The walls at the back of the sty should be at least
five feet high, and those at the side should gradually slope
downwards to the yard, to about three feet and a half. The
roof always productive of the greatest comfort to the inmates
is found in good straw thatch ; for this substance tends not
only to keep the apartment warm in winter, but also forms
the best protection against the sun's rays during the excessive
summer heat. The floor of the sleeping compartment should
consist of boards resting on planks raised at least six inches
from the ground, when the sleeping chamber can be shut in
two-thirds of the way across, by boards, bricks, or any other
building material that is ready to hand. The sties in which
breeding sows are kept will be beneficially supplied with a
ledge running round the chamber, and raised about six
inches from the floor and extending over it about one foot.



Online LibraryW. J. (William J.) MilesModern practical farriery : a complete system of the veterinary art as at present practised at the Royal Veterinary College, London → online text (page 152 of 160)