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GOAT MILK VERSUS COW MILK
By: "Goat Handbook, United States, 1992"
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About the Author
Breeds
Domestic goat breeds are many. Swiss breeds are distinguished in milk producing ability and have
influenced significantly milk production from goats around the world, especially in Europe, North America, Australia and New Zealand. A few breeds kept mostly for meat are the South African boer goat, the Indian beetal, black Bengal, the Latin American criollo, the US
''Spanish'' goats and most of the small or nondescript goats. Fiber producing goat breeds are the Angora in Turkey, USA, South Africa; the Cashmere in Afghanistan, Iran, Australia and China; and Don breed in Russia.
The major breeds of US goats are:
a.. Saanen originate from Switzerland (Saanen Valley),
are totally white, with or without horns. The white color
is dominant over other colors. They are mostly short
haired. The ''Appenzell'' is a similar breed, but
partially related to the Toggenburg from Northern
Switzerland, longhaired, white and hornless. Saanen have
been exported around the world as leading milk producers.
An Australian Saanen doe holds the world record milk
production of 7,714 lbs in 365 days. Saanen had been bred
in Switzerland for odorfree milk long ago.
b.. Toggenburg, brown with white facial, ear and leg
stripes, another straight nosed, horned or hornless,
mostly shorthaired, erect eared goat, as all Swiss are,
has been very popular in the USA, comes from N.E.
Switzerland, but is 4 inches shorter in height and 18 lb
lighter in average than the Saanen. They have been bred
pure for over 300 years, longer than many of our other
domestic breeds of livestock. They are reliable milk
producers summer and winter, in temperate and tropical
zones. Mrs. Carl Sandburg, wife of the famous US poet had
several world record Toggenburg does on official USDA
tests.
c.. Alpine (including French, Rock and British),
another Swiss breed (French Switzerland), horned or
hornless, shorthaired, as tall and strong as the Saanen,
with usually faded shades of white into black, with white
facial stripes on black. They are second in milk
production to Saanen and Toggenburg.
d.. LaMancha is a new, young breed developed in
California from Spanish Murciana origin and Swiss and
Nubian crossings. They are known for excellent
adaptability and good winter production. They are also
producing fleshier kids than the Swiss, but are not
milking as much. They have straight noses, short hair,
hornless or horns, and no external ear due to a dominant
gene. They are more the size of Toggenburg. Their milk
fat content is higher than that of the Swiss breeds.
e.. (Anglo)-Nubian is a breed developed in England from
native goats and crossed with Indian and Nubian which
have heavy arched ''Roman'' noses and long, drooping,
pendulous ears, spiral horns and are shorthaired. They
are leggy and as tall as Saanen, but produce less milk,
though higher milk fat levels and are more fleshy. They
are less tolerant of cold but do well in hot climates.
They ''talk'' a lot, and are in numbers the most popular
breed in USA and Canada. They have a tendency for
triplets and quadruplets. They are horned or hornless and
have many colors that may be ''Appaloosa''-like spotted.
f.. Oberhasli, a western Swiss breed, usually solid red
or black, horned or hornless, erect ears, not as tall as
Saanen, very well adapted for high altitude mountain
grazing and long hours of marching; popular in
Switzerland, but milk production is variable. They are
also called Swiss Alpine, Chamoisie or Brienz.
g.. Angora originated in the Near East. The long upper
coat (mohair) is the valuable product in the Angora in
contrast to the Cashmere, where the fine underwool is the
valuable product. Head has a straight or concave nose,
thin, not very long; pendulous ears and twisted horns, in
both sexes. It is a small breed, usually white. The
haircoat is long with undulating locks and ringlets of
fine, silky hair. The top quality fleece of purebreds may
be 1-2 lbs, but slightly more in males and wethers. They
are bearded. Spring moult is natural and shearing occurs
just before. They are not very prolific and twinning is
less frequent than in other breeds.
h.. Pygmy are dwarf, short legged goats from West and
Central Africa and the Caribbean. Their growth rates and
milk production are relatively respectable, although low,
twinning is frequent and they are breeding all year
usually. They are adaptable to humid tropics and
resistant to trypanosoma.
i.. Others. There is little known about the so-called
Spanish or bush goats that are kept on the open range in
the Southwest mostly. Also, a few minor breeds exist in
this country, e.g. the Sables, which are a colored
variety of the Saanen. It would be profitable to know
more about the other at least 60 goat breeds in the world
and their comparative values under US conditions.
Adjustment Factors for Milk Records
Lactation records of milk and fat production provide
important information for managing a dairy goat herd and
for breeding better goats. Environmental factors such as
length of lactation, age of doe, and season of kidding
should be standardized through appropriate adjustment
factors to make genetic evaluations more accurate.
A lactation length of 305 days has been defined as the
standard for dairy cattle and also is used for goats.
This standard assumes a 365-day interval between
parturitions, which includes a 60-day dry period.
However, many goats do not milk 305 days. A recent study
shows that only one-third of all does with official
records ending with a dry date milked 305 days. One
reason for shorter records is that production of many
does declines sharply with the onset of seasonal estrus
and the does then are dried off. A standard lactation
length of less than 305 days might be more useful for
comparisons among does; however, the 305-day standard
allows for reduced computing costs because doe and cow
records can be computed the same way.
If a doe's lactation ends on or before 305 days because
her production declined to the point at which continued
milking was not worthwhile, then her record is considered
complete. Such records are not projected to 305 days but
are treated as complete 305-day records. If a lactation
ends before 305 days for any reason other than going dry,
such as the doe's being sold or the herd's discontinuing
testing, the record is considered incomplete and is
adjusted. If a doe is still milking and has fewer than
305 days in milk, the record is considered incomplete,
adjusted, and referred to as a record in progress. If a
doe milks for more than 305 days, the production for only
the first 305 days is included in the 305-day record.
A method to adjust incomplete records and records in
progress uses the USDA projection factors in Table 1.
Different categories of factors are required to adjust
records because of variations in the lactation curve,
particularly in the rate of decline of production after
the peak and the number of days milked. To select the
appropriate factor, the following information is
necessary: breed, herd average production, month of
kidding, days in milk, and age of doe at kidding. An
adjusted or projected record is the incomplete record
plus an estimate of production for the rest of the
lactation. That estimate is the projection factor times
the last sample-day production times the number of days
from the end of the incomplete record through 305 days.
Suppose a Nubian doe freshens in March at 25 months of
age. She has an incomplete record at 130 days of 800 lb
milk and 27 lb fat. Her last sampleday production is 5 lb
milk with 3.4 The herd average is 1,725 lb. Then, her
projected record would be 800+0.69(5) (305-130) =1,404 lb
milk and 27+0.76(5) (0.034) (305-130) =50 lb fat.
Age-Season Lactation production increases with age until
maturity and then declines. Month or season of kidding
also influences lactation production. For example, does
kidding in the early spring produce more milk than those
kidding later in the year. Lactation records can be
adjusted to a common age and season of kidding to
standardize the effects of age and season. The factors in
Table 2 standardize production to that expected from a
doe kidding from January through March at 36 months of
age.
The adjustment factors vary by breed, age, and season of
kidding. Records are adjusted for age and season by
multiplying production by the appropriate factor from
Table 2. To illustrate, consider the Nubian doe from the
previous example: Adjusted milk=1.07(1,404)=1,502 lb
Adjusted fat=1.08(50)=54 lb.
The factors in Table 2 were computed by assuming a smooth
change by age and by ignoring lactation number. Recent
results, however, suggest that lactation number should be
considered, particularly for does kidding about 24 months
of age. Equations recently developed at the University of
California in Davis provide factors that vary by parity.
These factors may be more accurate; however, the factors
reported here should contribute to improved comparisons
among does.
Artificial Insemination
If you have a few backyard does that you enjoy as a
hobby, with little concern for genetic improvements of
their offspring, then artificial insemination (AI) is
probably not for you, assuming a suitable buck can be
located for servicing the does. The expense of purchasing
the necessary equipment and learning to do AI are likely
not worthwhile. However, if there is an experienced
inseminator in the area who is willing to work with your
goats, then this may prove to be a viable alternative and
certainly is much simpler than hauling your does in heat
to the buck's home.
AI has some key advantages over natural breeding.
a.. It eliminates the necessity of keeping one or
several bucks on the farm (depending on herd size). Costs
of feeding, housing, separate fencing and labor are
eliminated. However, heat detection may be more difficult
in the absence of a buck.
b.. AI can increase the rate of genetic improvement in
an herd, as long as superior bucks are consistently
selected. In natural service, the prospective breeder has
only the buck's pedigree to rely on, whereas AI bucks
should be progeny tested for their transmitting ability
of milk and fat percentage, weight gain, type
conformation, etc.
c.. AI allows breeding of different portions of the
herd to different bucks. Young does may be bred to not
yet proven but high potential bucks, while the majority
of the herd can be bred to proven high quality bucks.
d.. AI permits breeding of many does on one day when
synchronization is practiced. No long drives to top bucks
are involved.
e.. The danger of transmission of diseases or parasites
is greatly reduced. (The transmission of diseases through
frozen semen needs further study.)
f.. The time of breeding can be more carefully
regulated, and the owner knows exactly when the doe was
bred, as opposed to pasture servicing by a buck that is
allowed to run with the herd.
g.. AI induces good recordkeeping of dates of heat,
breeding, pedigrees, etc. This will aid in herd
improvements and enable the owner to make better culling
decisions.
Once the decision to use AI has been made, the next step
is to determine whether to do the inseminating yourself
or pay someone else to do it. If there are only a few
does in your herd, and an experienced inseminator of
goats is available, then it may be more practical to pay
to have the service done. However, if the number of does
in the herd is rather large, or an experienced
inseminator is nowhere to be found, then its probably
time to learn how to practice AI techniques yourself.
AI technicians of the cattle industry may not necessarily
be of much help when it comes to inseminating goats, for
the modern method of inseminating cattle (rectal
palpation) differs from that of breeding goats (speculum
method) considerably. The speculum was used on cattle
early in AI history, and some cattle inseminators may be
capable of teaching goat insemination.
The cost of getting started in AI, not including semen
purchases, will generally run around $500, of which $400
to $450 is tied up in the liquid nitrogen tank, which is
necessary for storing semen any length of time.
Temperatures must be kept at -320F (-196C) for sperm
survival to be maximized at breeding time. It may be
possible to share the cost of the tank with neighboring
goat owners or dairy farmers, thus alleviating some
initial costs of an AI program.
If AI is to be used with any hope of achieving a good
level of success, much must be known and well understood
by the prospective inseminator.
a.. basic knowledge of the doe's reproductive organs
and their functions
b.. understanding of storage and handling of semen
c.. ability to use, in a proper and sanitary manner,
the equipment required for inseminating goats
d.. ability to accurately detect heat at an early stage
e.. necessity of keeping accurate, up to date records
of heat cycles, breeding, kidding, reproductive problems,
treatments, and any other pertinent information that may
reflect on the goat's reproductive patterns.
Reproductive Organs and Functions
The two ovaries are the sites of egg formation. They
produce estrogens and progesterone, and as such are
determining factors of heat cycle, ovulation and
pregnancy. Basically the estrus (heat) cycle in goats
operates as follows:
a.. Proestrus is the time of follicle growth. As an egg
(ovum) begins to mature in an ovary, it becomes
surrounded by a fluid filled sac on the outside of the
ovary, much like a blister forms on the skin. This growth
is accompanied by increasing levels of estrogen in the
blood.
b.. Estrus - As estrogen levels peak, the doe will come
into heat. This can be observed by changes in behavior
(increased bleating and restlessness), willingness to be
bred, and the swelling of the external genital area. The
period of ''standing heat'' (acceptance of the buck) will
generally last for 24 to 36 hours.
c.. Ovulation, or the release of the egg, is
accomplished by the rupturing of the follicle, expelling
the egg from the ovary, and receiving it into the oviduct
via the fimbria funnel. This occurs very near, or soon
after, the end of standing heat (6 hours before to 12
hours after). Egg life is 12 to 24 hours, while the sperm
lasts 24 to 48 hours.
d.. Metaestrus - in this stage, the ruptured follicle
is undergoing cellular differentation to form a
functionally important tissue mass, the corpus luteum
(yellow body). This structure is responsible for the
secretion of progesterone, a hormone which prevents the
development of another follicle and prepares the uterus
to receive a fertilized egg.
e.. Diestrus - is the longest period of the estrous
cycle in does. During this period of corpus luteum
influence, two events may happen. If fertilization of
the egg occurred, the corpus luteum will persist for the
entire gestation period, preventing follicular
development and keeping estrogen levels low. If no
fertilization took place, the progesterone secretions of
the corpus luteum gradually lessen, allowing a new cycle
of follicular development to begin, with a corresponding
increase in estrogen levels. The length of time required
for one estrous cycle without fertilization, ranges from
17 to 24 days in goats, with the majority taking 21 days.
Shorter cycles are not uncommon (5-10 days).
f.. The egg, after being expelled from the ovary,
passes into the oviduct via the infundibulum, and toward
the cornua (horns) of the uterus. This movement is
produced by wave-like motions of the ciliated (hair-like
projections) cells of the oviduct. Sperm and eggs meet in
the oviduct and fertilization occurs in the middle to
upper one third of the duct.
g.. The egg continues into the horn of the uterus,
where, if it has been fertilized and undergone several
cellular divisions, it will become attached to the
uterine wall. If no fertilization has occurred, the egg
will degenerate and the cycle goes on.
h.. The cervix of the uterus plays a key role in
artificial insemination, as it is the external entrance
to the uterus which must be located and penetrated with
the inseminating instrument. The cervix is normally
tightly closed, except during periods of heat or kidding.
Semen is deposited on the vaginal side of the cervix in
natural services, but AI requires the deposition of semen
in the uterine side of the cervix. This is because of the
greatly reduced volume of semen that is used in AI. If
the 0.5 to 1 cc of semen in AI were deposited on the
vaginal side of the cervix, there is a good chance that
none of the sperm would reach the egg.
i.. The vagina serves as the connecting tube between
the uterus and the outside opening, the vulva. It is part
of the birth canal, and also contains the urethral
opening, from which urine will pass during emptying of
the bladder.
Purchase and Preparation of Semen
In most cases, the inseminator will acquire the semen
needed by direct purchase from a commercial operation, in
which case it will be shipped to the inseminator. It is
of the greatest importance that the semen be transferred
to permanent storage (the liquid nitrogen tank) without
exposing it to anything approaching air temperature.
Generally, this means transferring the container element
which houses the semen directly to the liquid nitrogen
tank. Here it can be safely stored for long periods of
time, since biological activity practically stops at
liquid nitrogen temperatures (-320F). Semen is generally
to be used within 6 months, but conceptions have resulted
from semen stored for several years, although sperm
survival is decreased, resulting in lower conception
rates.
Semen Collection Bucks are handled basically the same way
as bulls for semen collection. Three basic methods may be
employed, but all three require an artificial vagina, a
double walled device with an opening at one end and
collection tube at the other. The inner lining holding
warm water should be coated with a light application of
water soluble lubricating jelly.
The three methods of semen collection are:
a.. A buck may be allowed to mount a doe, with the
semen collector manually diverting the buck's penis into
the artificial vagina (ram or dog size). Don't touch the
penis directly, instead direct the penis into the
artificial vagina by grasping the buck's sheath. After
ejaculation (usually 0.5 to 1.0 cc) has occurred, remove
the artificial vagina and tip it so that the semen will
all run into the collection tube. This method may require
practice and adjustment by both the buck and the
collector before good samples are collected.
b.. A buck is trained to mount a dummy instead of a
live doe. The same procedures are followed for sample
collection. Mounting may be facilitated by applying
vaginal mucus scrapings of a doe that is in heat to the
dummy, at least during the training process.
c.. Use of electro-ejaculation. The buck is not
required to mount an object, although an artificial
vagina should still be used for semen collection. An
electrode unit, which has a number of contact rings, is
inserted into the buck's rectum. Slight electric
stimulation brings on ejaculation. This technique
generally results in good samples in quantity and
quality. However, the sperm concentration of the sample
will be lower. This method does not require extensive
training, and will allow collections from bucks that may
refuse or are unable to mount and serve an artificial
vagina.
Semen, once collected, may be used in one of three
different ways:
a.. As liquid semen, directly or on the same day one
ejaculate can serve 3 to 5 does. If kept at body
temperature, the semen may be good for three hours.
b.. Semen may be stored 24 to 48 hours by placing the
collection tube in a container of water and putting this
unit in a refrigerator. No diluter is needed, although
plain egg yolk can serve as simple extender to double the
number of does that can be served.
c.. Semen that is to be stored for longer periods of
time must be mixed with a diluter and very carefully
frozen. A commercially prepared diluter extender, such as
Ortho Semen Diluter is desirable, although plain milk can
be used successfully also.
Following are steps in semen extending:
1.. With a commercial preparation, use a diluter to
semen ratio of 19:1, adding the semen to the diluter, and
rolling the bottle gently to achieve a thorough mixing.
The semen and diluter should be at the same temperature.
This mixture can be stored in the refrigerator and used
for a week, or slowly cooled and stepwise frozen for
storage in a liquid nitrogen tank for later insemination.
2.. For a homemade milk diluter, it is best to use
fresh 3.5 pasteurized, homogenized whole milk. It must be
heated and held at 210F for 10 minutes in a glass boiler,
keep the lid in place so that no moisture is lost. Next,
the milk is cooled in a water bath with the lid on. When
the milk is in equilibrium temperature with the water
bath, the water condensation on the inside of the lid is
shaken back into the milk. To every 400 cc of milk, add
100,000 units of potassium G crystalline penicillin and
500 mg crystallin di-hydrostreptomycin sulfate, mixing
well. Warm this diluter to about body temperature before
adding the fresh semen at 19:1 ratio. Place the diluted
semen in a water bath at body temperature of 101F and
allow to cool slowly. Semen may be frozen, if the
extender contains an antifreeze compound, slowly,
stepwise for storage on dry ice or in liquid nitrogen.
3.. A microscope, capable of 900x magnification is an
essential tool when doing your own semen collection in
order to determine semen quantity and quality. First,
place a semen sample on a clean slide and cover with a
coverslip or another slide. Set the magnification to 400x
and observe the appearance of dark patches or spots thru
the scope; four dark areas or more per microscope field
represent high concentrations of sperm, a really good
sample. Three dark areas is somewhat chancy for use at a
diluted service, but is good enough for natural service.
Two dark areas should be used only for natural services
and one dark area means that the concentration of sperm
is too low for even natural service. Switching to 900x,
the sperm cells can be individually observed for normal
structures. Diluting in warm saline is helpful. Coiled
tails, broken tails, absence of tails and abnormal shapes
all constitute deficient sperm cells. Sixty to 70% good
motility before freezing should be observed in a good
sample, with a minimum of 30% motility after freezing and
thawing.
Any insemination program, no matter how carefully carried
out, will yield poor results if the concentration and
quality of the collected sperm is not of high standards.
Sophisticated techniques of washing the sperm free of
seminal plasma before extending and freezing will improve
post-thaw viability.
The concentration of a buck semen ejaculate can be
determined accurately by using a red blood cell diluting
pipette and standard hemocytometer techniques. Typical
results during the breeding season are 3 to 5 billion
sperm per cc. Optical density can also be used to
estimate sperm concentration if the photometer has been
calibrated for buck semen. A simpler technique involves
the determination of a spermatocrit using microhematocrit
pipettes. The aliquot of semen is centrifuged for 10
minutes; for each percentage point of packed sperm,
approximately 200 million sperm cells per cc are present.
Correction is made for the percent motile sperm, after
which the ejaculate can be diluted appropriately to
supply a minimum of 125 million motile sperm in each
breeding dose. It is often difficult to introduce more
than 0.2 ml of semen into the cervix, so dilution to a
final concentration of 600 million to 1.2 billion live
sperm per cc has been recommended. When no laboratory
support is available, fresh semen for immediate use may
be diluted up to 5 times in extender if it is yellowish
and 10 times if the ejaculate is white. A straw holding
0.5 cc of this diluted semen will provide adequate sperm
if excessive reflux does not occur.
Storage and Removal of Semen from the Liquid Nitrogen Tank
A liquid nitrogen tank is basically a very large
thermos-bottle in which liquid nitrogen is placed to keep
the inner temperature near -320F (-196C). The spacing
between the inner and outer walls is insulated and under
vacuum. The temperature in the tank is maintained
uniformly at -320F up to the bottom of the tank neck
until the liquid nitrogen level gets down to around 5''.
To measure liquid nitrogen, use a piece of black metal
rod that is long enough to hold and touch the bottom of
the tank. Dip the rod to the tank bottom and remove after
30 seconds. By waving it in the air, a white frost line
will appear on the rod. This line indicates the liquid
nitrogen depth of the tank. Levels nearing 5'' require a
refill. The only real differences between tanks is their
storage capacity (number of ampules or straws that they
will hold) and their length of holding time (liquid
nitrogen evaporation rate). The neck diameter varies
somewhat also, with wider openings being easier to work
with, but an increased evaporation rate usually results.
When working with semen in the liquid nitrogen tank, it
is important to keep the racks below the frost line in
the neck of the tank. Removal of semen from the tank for
periods as brief as 10 seconds, such as for
identification, before replacing it to the tank will
often result in lowered fertility levels. If the right
rack can't be located in 5 seconds, lower the canister
back to the bottom of the tank for at least 30 seconds
before trying again. Also, when handling semen, try to
stay out of any direct sunlight, as ultraviolet light has
a spermicidial effect.
The semen comes in two basic types of packaging: ampules
(1 ml) and straws (0.5 or 0.25 ml). The ampule is the
most common type of packaging for buck sperm. Both
ampules and straws are stored in racks (canes), which are
aluminum pieces that hold a vertical row of ampules,
usually six.
A few key reminders concerning semen storage:
a.. Always keep the liquid nitrogen level above 5''.
b.. Never lift a canister above the frost line of the
tank.
c.. When the semen is removed with a forceps from the
tank it should be placed immediately in the thaw box.
d.. Never expose semen to direct ultraviolet light.
e.. Never refreeze semen that has been thawed as it
will be destroyed.
f.. Check for proper identification on ampule or straw.
g.. A defective ampule may blow up after it is removed
from the tank. This is due to a small leak that allows
nitrogen to enter the ampule. When removed from the tank,
the gas expands too rapidly to vent back out the hole and
it explodes the glass. A hissing sound is usually audible
when it is removed. Keep your hand between the ampule and
your face when putting it into thaw box.
h.. Always wear gloves and goggles for your own
protection when working inside a liquid nitrogen tank.
Thawing Procedures
Methods for semen thawing vary among manufacturers, and
it is best to follow their recommendation. The thawing
procedure for 1cc ampules, the most common for goat
semen, is generally the ice water bath.
Ice water (38-42F) is placed in a styrofoam box long
enough before-hand to allow temperature to equilibrate.
Remove the ampule from tank and place immediately into
thaw box. Ampule may be placed in a small plastic cup
with holes in the bottom. This prevents ice from coming
into direct contact with ampule. Ampule should thaw in 3
to 5 minutes. Check for slushiness and allow more time if
needed. Ampule may sit in ice water for as long as 30
minutes with no damage. Once removed, the semen must be
used right away. The layer of ice on the ampule must be
peeled off before opening to avoid possible
contamination. The ice water thaw method is especially
good during winter breeding of does because of low risk
of cold shock to thawed and exposed semen. Thawing of
semen can be done from -320F rapidly, but any subsequent
exposure to lower temperatures after thawing will kill
many or all of the sperm.
The warm water method of thawing is more exact than the
ice water method, but probably will not work in cold
weather, although it may give somewhat better results the
rest of the year. The procedure is basically the same as
for the ice water thaw except that the water must be
maintained at 92 to 98F. This requires a source of warm
water and an accurate thermometer. Thawing will be
complete in about 1 minute with no ice layer formation of
the ampule. Ampules thawed with the warm water method
should be used within 5 minutes.
Straws (0.5 or 0.25 m
l) can be thawed by either of the
previous two methods. A given amount of semen in a straw
will take about one half as long to thaw as an equal
amount in an ampule. Many inseminators simply thaw straws
by placing them into their shirt or pants pocket.
Inseminating Procedures
All the care in handling, storage and preparation of
semen will be useless if the inseminating process is not
done carefully and cleanly. Hygienic practices at this
point cannot be over-emphasized. All reusable items such
as inseminating guns (for straws), scissors for cutting
straws, scribe for cutting ampules, etc. must be wiped
clean with 70 0sopropyl alcohol and allowed to dry before
reuse. Disposable items should be kept in their sealed
packages until they are to be used. The speculum should
be sterilized after each use (this is one reason why the
cattle industry discontinued the speculum method; the
inseminator would have to carry a few dozen specula on
his daily rounds, sterilizing them each night). This is
best accomplished by boiling for 10 minutes, allowing to
air dry. Then place inside a sterile container or
wrapping, such as a new plastic AI glove. Disposable
plastic type specula for goats can be obtained from mail
order companies, eliminating the need for constant
resterilization.
Materials needed for artificial insemination:
a.. Speculum, Pyrex 22 x 175 mm for doelings; 25 x 200
mm for adult does; or stainless steel human vaginal
speculum; or plastic disposables; with a small clip-on
flashlight.
b.. Sterile lubricating jelly (K-Y)
c.. Thaw box
d.. Inseminating pipette with bulb or syringe (ampules
only) or Inseminating gun (straws only)
e.. Paper towels
f.. Facility for securing doe (stanchion, fence, rope
hoist)
g.. Recording journal for breeding dates, buck's name,
etc.
Preparing Ampules:
1.. Partially remove an inseminating pipette from its
plastic bag.
2.. Place bulb or syringe on exposed end.
3.. Thaw ampule according to the described methods.
4.. Dry ampule after thawing, hold in paper towel and
scribe (with proper tool) one side of ampule collar. Some
ampule types do not need to be scribed, but can be
snapped open.
5.. Pull syringe back 1/2 cc on plunger or squeeze bulb
closed before placing pipette into ampule. Tip ampule to
slight angle and maintain constant suction on pipette
while it is slowly inserted into the ampule. Try to get
all the semen into the pipette, keeping the semen column
down near the end of the pipette.
6.. When filled, the pipette should have a semen column
with no air spaces, with the bottom of the column being 1
to 2'' from the pipette tip. Do not draw semen into the
syringe or bulb.
7.. Keep the ampule for information to complete
breeding records.
8.. Keep the pipette away from sunlight or cover with
paper towels.
9.. The semen is now ready to be placed into the doe in
estrus.
Preparing Straws:
1.. An inseminating gun, designed for your type of
straw is needed, obtainable thru farm supply houses or
the local cattle AI technician. Have cover sheath
available, sealed until needed.
2.. Place straw in thaw box.
3.. Remove when thawed, wipe dry. Check buck
information.
4.. Pull plunger on gun back 4 to 6'' and insert straw
into gun, cotton plug end first (towards plunger).
5.. Hold gun in upright position, allowing air bubble
to rise to the sealed end.
6.. Cut sealed end of straw with scissors. Take care to
cut straw squarely for proper seating.
7.. Install the sheath over the gun, fastening it down
with the provided O-ring. Install it so that the wider
side of the ring faces the straw, with the narrower side
facing the syringe end.
Insemination:
Assuming that the doe has been observed in heat, has been
suitably restrained (i.e. in stanchion) and the steps for
preparing the ampule or straw have been followed. The
next steps are:
a.. Position doe on milk stand. The inseminator places
his left foot on the stand and drapes the hindquarters of
the goat across his horizontally positioned thigh. The
goat is allowed to stand as long as she does not struggle
or collapse. The vulva is cleaned.
b.. Hold pipette or inseminating gun, wrapped in a
paper towel, in your mouth; or let someone else hold it
if extra hands are available.
c.. Turn head light on and insert lubricated speculum
in a slow and gentle manner. Begin entrance at a somewhat
upward angle for the first several inches. This is to
prevent the speculum from scraping across the vaginal
floor, possibly doing damage to the urethral opening.
d.. Complete insertion of speculum and locate cervix.
Center the end of the speculum over the os uteri
(entrance to cervical canal).
e.. Cervix should be of a red-purple coloration with a
viscous whitish mucus present if doe is truly in heat.
f.. Insert pipette or inseminating gun into speculum to
the cervix. Gently manipulate the instrument through the
cervical canal (cervix is 1 to 2'' long) to the 4th or
5th annular ring.
g.. Deposit semen near the uterine end of the cervix or
just inside the uterus. Do not enter too far into the
uterus as the semen will then tend to be dumped into one
horn or the other. If the semen is pushed into the wrong
horn (i.e. egg produced in left ovary, semen dumped into
right horn) then fertilization may not occur.
h.. Deposit semen slowly, taking at least five seconds.
i.. Slowly withdraw instrument without release of
syringe or depressed bulb, then carefully remove the
speculum.
j.. Record all pertinent breeding information.
k.. Carefully discard all disposable materials. Arrange
to sanitize reuseable items and sterilize the speculum
(if it is a non-disposable type).
Frequently, the pipette cannot be passed all the way
through the cervix even though the doe is in heat. If it
has penetrated deeply into the cervix (3 to 4 cm, as
determined by laying another pipette alongside the first
and observing the distance by which the outer ends are
offset), cervical insemination will provide a conception
rate almost equal to that of intrauterine semen
deposition. The conception rate expected from
intra-vaginal insemination, however, is less than 30. If
semen is very valuable, it may be advisable to pass a
trial pipette to determine patency of the cervix before
thawing the semen unit.
In France, a doe is usually restrained by a second person
who straddles the doe's neck and elevates the
hindquarters to a vertical position while holding the
hind limbs tightly flexed. The inseminator is free to
stand in a comfortable position. He holds the speculum
and the goat's tail in one hand and the pipette or straw
gun in the other hand. If excess mucus is a problem, the
assistant lowers the goat's hindquarters almost to the
ground; if the mucus does not run out of the speculum,
the latter is removed and shaken to clear it. The goat is
then lifted to its former position. If many goats are to
be bred, the assistant may tire using this technique. If
the doe is not held in a vertical position, it is often
impossible to adequately visualize and penetrate the
cervix. Various slings have been devised to suspend the
goat in the appropriate position.
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