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by Monika Yost
Temperature At this time it has been determined that temperature, light
conditions, health, and harvesting methods, as well as feed can
influence the amount of fibers produced in the secondary follicle
as well as the texture. The OPTIMUM temperature for top fiber
production is right at 50 degrees Fahrenheit. At this temperature,
the just sheared rabbits will not be so cold as to affect the
skin or health of the rabbit, yet encourage maximum wool production.
Colder temperatures would also benefit wool production. However,
at colder temperatures, the just sheared rabbits would get cold
and may get sick. Also, the skin of just sheared rabbits is affected
negatively by cold temperatures, causing the skin to become thick
and leathery, with less density in the new wool growth. Therefore,
even though a colder temperature benefits wool production after
the first insulating growth of wool has occurred, it is not of
benefit to expose the rabbits to colder temperatures right after
shearing. Warm temperatures also have a negative effect on wool
production, since the secondary follicles produce more fibers
in cold temperatures than in warm temperatures, and fiber growth
itself is accelerated in colder temperatures. Light Recent studies have shown that light, or rather the LENGTH
OF DAYLIGHT HOURS affect the rate of growth of Angora wool fibers.
Nature predicts that as the daylight hours lengthen, temperatures
rise, and wool does not need to be as dense and long as it needs
to be in colder temperatures. Vice versa, as the daylight hours
shorten, nature predicts temperatures to become colder. German
test stations tested this theory and successfully determined
that the amount of light offered to Angora rabbits does affect
the rate of growth as well as the density. This stands in direct
conflict with the production of offspring and a happy medium
needs to be found to aid production of offspring as well as top
wool production. It is therefore not advisable to have your Angora
herd under constant light, since this does give the effect of
summertime with less wool production as a result. However, we
also know that a minimum of light is needed to keep does in production
of offspring. Number of Follicles Per Unit of Skin The number of follicles per unit of skin is truly genetic
and is inherited from both parents equally. In other words, a
doe that has 250 follicles in a specific unit, mated to a buck
with 350 follicles in that same unit will produce offspring that
has 300 follicles in that same unit. This theory was later supported
by the fact that studies have been undertaken to determine follicles
in a specific unit in various populations and crosses of various
populations. It was found that offspring of the crosses had half
of the sum of the follicles of both parents combined. In direct
relation, the wool production was also half of the sum of the
production of both parents. The number of follicles in a unit
cannot be increased through environmental changes. However, scarring
can decrease the number of follicles in a particular unit. This
scarring is not inherited but is strictly environmental and only
affects the wool production of the scarred animal. Limitations due to Population Various Angora breeds or populations have a genetic limitation as to the quantity of wool they can produce. Chinese populations are showing the least wool production, with German populations capable of producing 8 times as much, while English, Russian, and Japanese are limited to approximately half of the German population. This is not surprising, because many factors play a role in this development. Many of these factors are purely environmental, such as feed causing the animals to be smaller, less productive; light and temperature conditions also interfering with the animals’ actual potential. However, when making true comparisons with animals from various populations, placing them under the same conditions, there still was a big difference in wool production which is now purely genetic. This again is determined by size difference of the various populations, but also is due to the lack of proper selection for quality and quantity of wool production; preferences in the exterior appearance of the various populations, and the inherited number of follicles per unit. The quantity of wool produced is limited as per population of Angora. Through selection, various populations have been developed, each with their own characteristics, the English Angora, a small sized rabbit, averaging 6 – 7 lbs cannot possibly produce the same amount of wool that a 10 – 12 lgs rabbit can produce. The English Angora also has another characteristic that genetically correlates to lower wool production – heavy furnishings. The heavier the furnishings, the lower the wool production, and the finer the wool, causing more chance for matting. Through the years, the English Angora has been plucked. Plucking injures the secondary follicles that do not shed at the same intervals as the primary follicles. These injuries eventually form scars and less fiber is produced. It has been found that a genetic change has taken place as well, causing less production – an adaptation, a genotype environmental interaction. Even if the English Angora now is sheared from the very beginning and is never plucked, the overall wool production will not compare to a German Angora of the same size. Taking skin samples from various populations showed a higher amount of fiber per cm2 in the German populations than any other population due to the difference in harvesting method. The same goes for the French Angora, which is comparable in size to the German Angora. However, again the population has been plucked for generations, causing the above mentioned genotype environmental interaction. It appears that the French Angora has more guardhairs than the German Angora, however that has been disproved. The appearance is caused by the method of harvest. Since the wool is plucked when guardhairs shed, the undercoat is pulled out of the secondary follicles before they are ready. By the time the secondary follicles are ready for their cycle and start to grow their new fibers, the guardhair has already grown for some time. This gives the appearance of a higher amount of guardhair. Tests have revealed that there is only a 1 – 3% variance in favor of the French population when actually counting the guardhairs. Guardhairs counted in the staple and compared to the total number of fibers in that staple revealed that German bucks had 1.5%, German does 1.8%, French bucks 2%, and French does 2.1% true guardhair. English and French Angoras are limited as to the wool they can produce because of their genetic inheritance due to selection, characteristics, and method of harvesting. It can be increased by changing the procedures for selection and harvesting, but it will take many generations and much patience. The German Angora of all Angora populations, is the one with
the highest wool production as well as quality and feed intake
correlation. Even this population is limited as to how much wool
it can produce. There are reports of higher and higher wool productions.
The highest right now is nearing 2500 gram – a doe owned
and produced by herdsobmann Peter Hoefer. However, there are
limitations, and sacrifices must be made when pushing animals
beyond their limits. It has been noted that bucks with extremely
high wool production tend to be sterile. Size As already mentioned above, the size of the animal does determine
its overall wool production. There is more surface area to a
larger animal than a smaller one. However, be forwarned that
a larger animal also consumes more food. Therefore it is necessary
to not only record the total wool production of the animal, but
also the amount of feed consumed to produce that amount of wool. Wool Quantity Wool Quantity is determined most commonly by weight. The animal’s
wool is harvested and all wool is weighed. However, there is
a difference between weight in the grease and clean wool weight.
Wool in the grease consists of the following: moisture, dirt,
and wool. The dirt in the wool can vary so much that the weight
of the fleece in the grease alone would be of little value as
a genetic indication for the true wool production. In selecting
according to the clean wool fleece weight per Angora rabbit,
the breeder is undoubtedly dealing with a polygenic situation
which results from the combination of the properties determining
the many variations of the fleece weight within the same blood
line. Influencing Quantity The quantity of wool is influenced by many environmental conditions,
such as temperature, type of feed, feeding schedule, amino acids,
timing of the harvest, and the harvesting methods. Temperature
is one of the major problems we as breeders have to contend with.
Unless we want to spend money to keep the temperature at a constant
50 degrees Fahrenheit, we have to expect a variation in wool
production, and take these variations into account when keeping
accurate records and comparing animals for future selection.
An animal is certainly going to produce more wool in the cold
winter temperatures, than another with the same POTENTIAL, that
has been tested in the heat of summer. Age Age also plays a major role in comparisons, 6 months being
the preferred age for testing. Again, not all of our animals
are going to be tested at the same time. Therefore, animals should
not be compared with one another if the age difference is more
than 2 months, because of the seasonal influences. Feed The type of feed is also a major problem for the breeders.
In various parts of the country one type of feed is available,
another is not. One feed is better than another. All you can
do to test your feed is to put groups of animals on different
feed available in your area. Each group should contain at least
5 rabbits from various families. Texture and quality of the wool
must be judged as well as judging the quantity of wool produced
by each group. Health and condition of the animals in each group
must be equally recorded. Some feeds are producing a dry, coarse
coat due to the ingredients that are in the feed or lacking in
it. Some feeds cause a thin coat due to heat producing ingredients.
You must test, in order to determine if you are looking at a
problem in feed or inheritance. Feeding Schedule The feeding schedule does play a part in wool production and quality of the wool. Animals only perform their best if they are healthy and happy. An irregular feeding schedule upsets the rabbits and stresses them. You must ascertain a schedule that works well for you as well as for them. Then you must adhere to that schedule as closely as possible. Angora rabbits going into stress do several of the following things: They shed before they should, their coat is dull and coarse, the coat is uneven, the fibers are weak and break. I already mentioned the importance of finding a feed that
works well for your rabbits and gives you the highest possible
production. Amino Acids play a major role in wool production.
Methionine is one major Amino Acid that has been found to actually
increase wool production and density. However, it needs to be
fed in limited amounts or production of offspring stops. Tests
have shown that smaller amounts of feed were needed when it contained
.77% Methionine than compared to feed containing .42% in order
to produce a kg of wool. Timing of the Harvest Timing of the harvest also affects overall wool production. Angora rabbits go through periodic shedding cycles. If the shedding is missed two things happen: You are losing a considerable amount of wool under the cage and in the cage and matting begins with more wool being lost to matts. If you have decided that your harvesting method is going to be shearing, then do not wait until your animals trail. Trailing is a definite sign that shedding is well underway. You must shear your animals prior to shedding – in their prime. Often it works to figure from the birth date of each individual rabbit and calculate in 3 month increments. This generally works. However, some animals do have an inborn tendency to shed in 2 ½ month intervals. You may need to adjust your schedule accordingly. If you have decided to harvest your wool by plucking (not recommended at all if you want to increase your wool production), you have already decided that wool production is not one of your major concerns. Wool production is adversely affected by plucking. When plucking, wait until the animal begins to trail, a sign that the primary follicles are releasing the old fiber and beginning to grow new ones. Unfortunately, the secondary follicles seldom shed at the same time as the primary follicles, and it is difficult to only harvest one fiber and not the other, aside from the fact that the remaining fiber tends to matt when lacking in the support offered by the guardhair. Scarring due to the plucking of secondary fibers are the result. Be prepared for less and less wool production from animals that you have decided to pluck instead of shear. |
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