| Some Thoughts on Slipped Wing Bernard Gil |
This article is not meant to be a scientific study, but only the personal observation
and experience of one breeder.
Slipped wing, also known as angel wing, is a condition in which the extremity of
the bird's wing, weakened by it's own weight during the early stages of the
primaries' development, folds at an unnatural angle to the body.
The majority of Muscovy breeders have, at one time or another, been faced with
this problem. This in turn has given rise to a variety of theories as to it's causes
and numerous approaches to its correction. These hypothetical causes cover a
wide spectrum of concepts ranging from the accidental stretching of the bird's
undeveloped wing tip to the presence of problematic genes. The most popular,
by far, seems to be the notion that the wing is deformed by the young bird's
accelerated growth, due to an overabundance of protein in it's diet. Unfortunately,
most of these ideas have never been verified.
Alleged cures also vary quite significantly. Some more colorful than others, but
most offering some degree of success, depending on the severity of the case
and at what stage the corrective manipulation is started. These procedures,
which usually call for the use of strings or tape, are meant to immobilize the wing
until the bone and cartilage have developed sufficiently to hold a more or less
natural position without assistance. For those who believe that nutrition is the
culprit, a reduction in the amount of protein fed to the young birds seems to be
the preferred course of action.
Personally, I am convinced that the problem is genetic; at least at it's base. By
that I mean, in order for a bird to develop slipped wing, it must first have the
genetic predisposition for it. Then, and only then, if the duckling is fed a diet high
in protein, will it develop the symptoms.
I make it a point of maintaining very accurate records and pedigrees (all my birds
are mated in pairs, making clutches genetically distinct from one another); this in
turn greatly simplifies the task of tracing the exact source of a problem. At first,
amongst my original Muscovies, the incidence of slipped wing in any given clutch
would range from 0% to 100%, depending on the strain. Since I have always
offered my young birds homemade rations containing high levels of protein,
several long time breeders led me to believe that the cause of my problem was
strictly nutritional. But the fact that it's manifestation varied so greatly from one
family to the next, made me question why some birds seemed resistant to the
affliction, while others fell prey to it; even if all had been consuming the same diet
and managed in the same way.
I soon began to notice obvious patterns within my breeding program. The most
important observation was that clutches in which all the young had slipped wing,
usually came from matings in which both parents had developed the condition as
youngsters, but had their wings "repaired." Another very important fact was that
when a clutch was totally free of slipped wing, the parents, if mated together in
future seasons would rarely, if ever, produce youngsters with the problem. There
had to be something more than just nutrition controlling the occurrence of this
deformity. Although I never got around to conduct any in depth experimental
breeding, I did however try quite a few test matings using birds that were either
afflicted or normal, but coming from clutches where only one parent showed the
condition. I also used birds from parents that had always produced normal
offspring. The results were pretty much predictable and consistent. Based on
those tentative findings, I would guess that the predisposition for slipped wing is
caused by one or possibly several recessive genes acting in unison. Hopefully, in
the near future, someone will be able to confirm this hypothesis.
As far as I'm concerned, repairing the wing of an affected bird, and using it as a
breeder, only whitewashes the problem. If Mendel's theory serves, all of that
bird's offspring will be, in some way, influenced by the condition...regardless of
what you mate with it.
Based on the theory that a simple recessive gene is responsible for the
predisposition to slipped wing, the following mating results can be expected, when
using an affected or "repaired" bird (the outcome would not necessarily be the
same should more than one gene be involved.)
1). When mated to a non-carrier of the gene -- all offspring appear normal but all,
without exception, are carriers.
2). When mated to a bird, which appears normal but is a carrier -- 50% of the
offspring are affected and the remaining 50% appear normal, but are carriers (the
percentage figures only reflect the odds of producing these results.)
3). When mated to an affected bird -- all the offspring are affected.
Naturally, these figures no longer apply if the bird's diet is altered during the early
stages of development. In fact, many breeders firmly believe that holding the
ducklings back nutritionally, by reducing the amount of protein ingested is a
prerequisite to proper wing formation. They will argue that a high protein diet is
unnatural, and that a slower rate of growth relieves the wing of excessive weight
before it is fully formed. I remain very skeptical about the validity of this
argument. Consider, for one moment, what wild Muscovies eat in their natural
habitat; you will notice that fish, small amphibians and insects are way up there on
the menu, making the consumption of large quantities of protein an integral part of
their lives. My personal experience has been that, ultimately, restricted birds don't
quite achieve their full potential. I am persuaded that resorting to diet tampering in
order to produce birds free of slipped wing, only perpetuates the camouflaging of
an abnormality, which can easily be eradicated by judicious breeding and record
keeping.
Again, I must emphasize that these are only my personal views and observations.
A qualified geneticist would be quick to point out many oversimplifications in this
text. I am a hobbyist writing for other hobbyists, and in no way am I urging
anyone to adopt a breeding or feeding program in lieu of another.
As I once commented to a friend; "Saying that high protein rations cause slipped
wing in waterfowl can be compared to saying that strobe lights, so widely used in
the 70's at the height of the disco era, cause epileptic seizures in humans. Sure,
strobe lights do cause epileptic seizures, but only if you're epileptic to begin with."
The genes load the gun, nutrition pulls the trigger.
and experience of one breeder.
Slipped wing, also known as angel wing, is a condition in which the extremity of
the bird's wing, weakened by it's own weight during the early stages of the
primaries' development, folds at an unnatural angle to the body.
The majority of Muscovy breeders have, at one time or another, been faced with
this problem. This in turn has given rise to a variety of theories as to it's causes
and numerous approaches to its correction. These hypothetical causes cover a
wide spectrum of concepts ranging from the accidental stretching of the bird's
undeveloped wing tip to the presence of problematic genes. The most popular,
by far, seems to be the notion that the wing is deformed by the young bird's
accelerated growth, due to an overabundance of protein in it's diet. Unfortunately,
most of these ideas have never been verified.
Alleged cures also vary quite significantly. Some more colorful than others, but
most offering some degree of success, depending on the severity of the case
and at what stage the corrective manipulation is started. These procedures,
which usually call for the use of strings or tape, are meant to immobilize the wing
until the bone and cartilage have developed sufficiently to hold a more or less
natural position without assistance. For those who believe that nutrition is the
culprit, a reduction in the amount of protein fed to the young birds seems to be
the preferred course of action.
Personally, I am convinced that the problem is genetic; at least at it's base. By
that I mean, in order for a bird to develop slipped wing, it must first have the
genetic predisposition for it. Then, and only then, if the duckling is fed a diet high
in protein, will it develop the symptoms.
I make it a point of maintaining very accurate records and pedigrees (all my birds
are mated in pairs, making clutches genetically distinct from one another); this in
turn greatly simplifies the task of tracing the exact source of a problem. At first,
amongst my original Muscovies, the incidence of slipped wing in any given clutch
would range from 0% to 100%, depending on the strain. Since I have always
offered my young birds homemade rations containing high levels of protein,
several long time breeders led me to believe that the cause of my problem was
strictly nutritional. But the fact that it's manifestation varied so greatly from one
family to the next, made me question why some birds seemed resistant to the
affliction, while others fell prey to it; even if all had been consuming the same diet
and managed in the same way.
I soon began to notice obvious patterns within my breeding program. The most
important observation was that clutches in which all the young had slipped wing,
usually came from matings in which both parents had developed the condition as
youngsters, but had their wings "repaired." Another very important fact was that
when a clutch was totally free of slipped wing, the parents, if mated together in
future seasons would rarely, if ever, produce youngsters with the problem. There
had to be something more than just nutrition controlling the occurrence of this
deformity. Although I never got around to conduct any in depth experimental
breeding, I did however try quite a few test matings using birds that were either
afflicted or normal, but coming from clutches where only one parent showed the
condition. I also used birds from parents that had always produced normal
offspring. The results were pretty much predictable and consistent. Based on
those tentative findings, I would guess that the predisposition for slipped wing is
caused by one or possibly several recessive genes acting in unison. Hopefully, in
the near future, someone will be able to confirm this hypothesis.
As far as I'm concerned, repairing the wing of an affected bird, and using it as a
breeder, only whitewashes the problem. If Mendel's theory serves, all of that
bird's offspring will be, in some way, influenced by the condition...regardless of
what you mate with it.
Based on the theory that a simple recessive gene is responsible for the
predisposition to slipped wing, the following mating results can be expected, when
using an affected or "repaired" bird (the outcome would not necessarily be the
same should more than one gene be involved.)
1). When mated to a non-carrier of the gene -- all offspring appear normal but all,
without exception, are carriers.
2). When mated to a bird, which appears normal but is a carrier -- 50% of the
offspring are affected and the remaining 50% appear normal, but are carriers (the
percentage figures only reflect the odds of producing these results.)
3). When mated to an affected bird -- all the offspring are affected.
Naturally, these figures no longer apply if the bird's diet is altered during the early
stages of development. In fact, many breeders firmly believe that holding the
ducklings back nutritionally, by reducing the amount of protein ingested is a
prerequisite to proper wing formation. They will argue that a high protein diet is
unnatural, and that a slower rate of growth relieves the wing of excessive weight
before it is fully formed. I remain very skeptical about the validity of this
argument. Consider, for one moment, what wild Muscovies eat in their natural
habitat; you will notice that fish, small amphibians and insects are way up there on
the menu, making the consumption of large quantities of protein an integral part of
their lives. My personal experience has been that, ultimately, restricted birds don't
quite achieve their full potential. I am persuaded that resorting to diet tampering in
order to produce birds free of slipped wing, only perpetuates the camouflaging of
an abnormality, which can easily be eradicated by judicious breeding and record
keeping.
Again, I must emphasize that these are only my personal views and observations.
A qualified geneticist would be quick to point out many oversimplifications in this
text. I am a hobbyist writing for other hobbyists, and in no way am I urging
anyone to adopt a breeding or feeding program in lieu of another.
As I once commented to a friend; "Saying that high protein rations cause slipped
wing in waterfowl can be compared to saying that strobe lights, so widely used in
the 70's at the height of the disco era, cause epileptic seizures in humans. Sure,
strobe lights do cause epileptic seizures, but only if you're epileptic to begin with."
The genes load the gun, nutrition pulls the trigger.
Copyright © 2006 Witt Farms. All rights
reserved.
reserved.