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Dwarfism In Chickens
Dwarfism in chickens is an inherited condition found in chickens consisting of a significant delayed growth, resulting in adult individuals with a distinctive small size in comparison with normal specimens of the same breed or population. The affected birds show no signs of dwarfism in the first weeks of age.Hutt, F.B. ''Genetics of the fowl''. McGraw-Hill Book Co. N.Y. 1949. Differences in size due to dwarfism appear slow and progressively along the growing stage. Poultry breeders begin to distinguish gradually dwarfs from normal birds by their shortest shanks and smallest body size. Depending on the breed, most types of dwarfism in chickens begin to be recognized when the birds reach 8–10 weeks of age,Hutt, F.B 1959 Sex-linked dwarfism in the fowl. ''Journal of Heredity'' 50:209-221Cole, R.K. 1973 An autosomal dwarfism in the fowl. Poultry Science vol.52:2012-2013 but classification is more precise when the chickens are five months old or more. At this point differences betwee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dwarf Rooster
Dwarf or dwarves may refer to: Common uses *Dwarf (folklore), a being from Germanic mythology and folklore * Dwarf, a person or animal with dwarfism Arts, entertainment, and media Fictional entities *Dwarf (Dungeons & Dragons), Dwarf (''Dungeons & Dragons''), a humanoid race *Dwarf (Middle-earth), a humanoid race in J. R. R. Tolkien's literature *Dwarf (Warhammer), Dwarf (''Warhammer''), a humanoid race *Dwarfs (Discworld), Dwarfs (''Discworld''), a race of characters *Dwarves (Artemis Fowl), Dwarves (''Artemis Fowl''), a race of characters *Dwarves (Warcraft), Dwarves (''Warcraft''), a short, strong race *Dwarves (Marvel Comics) Literature *The Dwarf (Cho novel), ''The Dwarf'' (Cho novel), a 1978 novel by Cho Se-hui *The Dwarf (Lagerkvist novel), ''The Dwarf'' (Lagerkvist novel), a 1944 novel by Pär Lagerkvist Other arts, entertainment, and media *Dwarfs (video game), ''Dwarfs?!'' (video game) *Dwarves (band), American punk band *Killer Dwarfs, Canadian heavy metal band *Wroc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bantam (poultry)
A bantam is any small variety of fowl, usually of chicken or domestic duck, duck. Most large chicken breeds and several breeds of duck have a bantam counterpart, which is much smaller than the standard-sized fowl, but otherwise similar in most or all respects. A List of true bantam chicken breeds, true bantam chicken is naturally small and has no large counterpart. Etymology The word ''bantam'' derives from the name of the Banten (town), seaport city of Bantam in western Java, Indonesia. European sailors restocking on live fowl for sea journeys found the small native breeds of chicken in Southeast Asia to be useful, and any such small poultry came to be known as a ''bantam''. See also * List of chicken breeds * American Bantam Association * Call duck - bantam breed of duck originally bred to attract wild ducks within the range of hunters with guns, now kept as pets * Dwarfism in chickens#Bantam dwarfism, dwB, Dwarfism in chickens References * * {{Authority control B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Applied Genetics
Genetic engineering, also called genetic modification or genetic manipulation, is the modification and manipulation of an organism's genes using technology. It is a set of Genetic engineering techniques, technologies used to change the genetic makeup of cells, including the transfer of genes within and across species boundaries to produce improved or novel organisms. New DNA is obtained by either isolating and copying the genetic material of interest using recombinant DNA methods or by Artificial gene synthesis, artificially synthesising the DNA. A Vector (molecular biology), construct is usually created and used to insert this DNA into the host organism. The first recombinant DNA molecule was made by Paul Berg in 1972 by combining DNA from the monkey virus SV40 with the Lambda phage, lambda virus. As well as inserting genes, the process can be used to remove, or "Gene knockout, knock out", genes. The new DNA can be inserted randomly, or Gene targeting, targeted to a specific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poultry
Poultry () are domesticated birds kept by humans for their eggs, their meat or their feathers. These birds are most typically members of the superorder Galloanserae (fowl), especially the order Galliformes (which includes chickens, quails, and turkeys). The term also includes birds that are killed for their meat, such as the young of pigeons (known as squabs) but does not include similar wild birds hunted for sport or food and known as game. The word "poultry" comes from the French/Norman word ''poule'', itself derived from the Latin word ''pullus'', which means "small animal". Recent genomic study involving the four extant Junglefowl species reveals that the domestication of chicken, the most populous poultry species, occurred around 8,000 years ago in Southeast Asia - although this was previously believed to have occurred later - around 5,400 years ago - in Southeast Asia. The process may have originally occurred as a result of people hatching and rearing young birds fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thyroid
The thyroid, or thyroid gland, is an endocrine gland in vertebrates. In humans it is in the neck and consists of two connected lobes. The lower two thirds of the lobes are connected by a thin band of tissue called the thyroid isthmus. The thyroid is located at the front of the neck, below the Adam's apple. Microscopically, the functional unit of the thyroid gland is the spherical thyroid follicle, lined with follicular cells (thyrocytes), and occasional parafollicular cells that surround a lumen containing colloid. The thyroid gland secretes three hormones: the two thyroid hormones triiodothyronine (T3) and thyroxine (T4)and a peptide hormone, calcitonin. The thyroid hormones influence the metabolic rate and protein synthesis, and in children, growth and development. Calcitonin plays a role in calcium homeostasis. Secretion of the two thyroid hormones is regulated by thyroid-stimulating hormone (TSH), which is secreted from the anterior pituitary gland. TSH is regula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aviculture
Aviculture is the practice of keeping and breeding birds, especially of wild birds in captivity. Types There are various reasons that people get involved in aviculture. Some people breed birds to preserve a species. Some people breed parrots as companion birds, and some people breed birds to make a profit. Aviculture Aviculture is the practice of keeping birds (class ''Aves'') in captivity using controlled conditions, normally within the confines of an aviary, for hobby, business, research and conservation purposes. Some reasons for aviculture are: breeding birds to preserve the species because many avian species are at risk due to habitat destruction and natural disaster. Aviculture encourages conservation, provides education about avian species, provides companion birds for the public, and includes research on avian behaviour. Publications and avicultural societies Publications on aviculture include books on species which include pets, books on breeding and introductory b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterogametic Sex
Heterogametic sex (digametic sex) refers to the individuals of a species in which the sex chromosomes are not the same. For example, in humans, males with an X and a Y sex chromosome would be referred to as the heterogametic sex, and females having two X sex chromosomes would be referred to as the homogametic sex. This arrangement is known as the XY sex-determination system. However, in birds and some reptiles, males have two Z sex chromosomes and so are the homogametic sex, while females, with one Z and one W chromosome, are the heterogametic sex. Platypus males are heterogametic while females are homogametic. Among the insects, Lepidopterans (butterflies and moths) have heterogametic females, but in ''Drosophila'', males are the heterogametic sex. This arrangement is known as the ZW sex-determination system. Heterogamesis can lead to reduced or absent meiotic recombination between the sex chromosomes, and in some species, this extends to the autosomes, a phenomenon called ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dwarfism
Dwarfism is a condition wherein an organism is exceptionally small, and mostly occurs in the animal kingdom. In humans, it is sometimes defined as an adult height of less than , regardless of sex; the average adult height among people with dwarfism is , although some individuals with dwarfism are slightly taller. ''Disproportionate dwarfism'' is characterized by either short limbs or a short torso. In cases of ''proportionate dwarfism'', both the limbs and torso are unusually small. Intelligence is usually normal, and most have a nearly normal life expectancy. People with dwarfism can usually bear children, though there are additional risks to the mother and child dependent upon the underlying condition. The most common and recognisable form of dwarfism in humans (comprising 70% of cases) is achondroplasia, a genetic disorder whereby the limbs are diminutive. Growth hormone deficiency is responsible for most other cases. Treatment depends on the underlying cause. Those w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chicken
The chicken (''Gallus gallus domesticus'') is a domesticated junglefowl species, with attributes of wild species such as the grey and the Ceylon junglefowl that are originally from Southeastern Asia. Rooster or cock is a term for an adult male bird, and a younger male may be called a cockerel. A male that has been castrated is a capon. An adult female bird is called a hen and a sexually immature female is called a pullet. Humans now keep chickens primarily as a source of food (consuming both their meat and eggs) and as pets. Traditionally they were also bred for cockfighting, which is still practiced in some places. Chickens are one of the most common and widespread domestic animals, with a total population of 23.7 billion , up from more than 19 billion in 2011. There are more chickens in the world than any other bird. There are numerous cultural references to chickens – in myth, folklore and religion, and in language and literature. Genetic studies have pointed to mult ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Broiler
A broiler is any chicken (''Gallus gallus domesticus'') that is bred and raised specifically for meat production. Most commercial broilers reach slaughter weight between four and six weeks of age, although slower growing breeds reach slaughter weight at approximately 14 weeks of age. Typical broilers have white feathers and yellowish skin. Broiler or sometimes broiler-fryer is also used sometimes to refer specifically to younger chickens under , as compared with the larger roasters. Due to extensive breeding selection for rapid early growth and the husbandry used to sustain this, broilers are susceptible to several welfare concerns, particularly skeletal malformation and dysfunction, skin and eye lesions and congestive heart conditions. Management of ventilation, housing, stocking density and in-house procedures must be evaluated regularly to support good welfare of the flock. The breeding stock (broiler-breeders) do grow to maturity but also have their own welfare concerns re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dominance (genetics)
In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome. The first variant is termed dominant and the second recessive. This state of having two different variants of the same gene on each chromosome is originally caused by a mutation in one of the genes, either new (''de novo'') or inherited. The terms autosomal dominant or autosomal recessive are used to describe gene variants on non-sex chromosomes ( autosomes) and their associated traits, while those on sex chromosomes (allosomes) are termed X-linked dominant, X-linked recessive or Y-linked; these have an inheritance and presentation pattern that depends on the sex of both the parent and the child (see Sex linkage). Since there is only one copy of the Y chromosome, Y-linked traits cannot be dominant or recessive. Additionally, there are other forms of dominance such as incomplete d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sebright (chicken)
The Sebright (IPA: ) is a British breed of bantam chicken. It is a true bantam – a miniature bird with no corresponding large version – and is one of the oldest recorded British bantam breeds. It is named after Sir John Saunders Sebright, who created it as an ornamental breed by selective breeding in the early nineteenth century.Hobson, Jeremy and Lewis, Cecilia. ''Choosing & Raising Chickens: The complete guide to breeds and welfare''. David and Charles publishing. London. 2009. p 85. The first poultry breed to have its own specialist club for enthusiasts, Sebrights were admitted to poultry exhibition standards not long after their establishment. Today, they are among the most popular of bantam breeds. Despite their popularity, Sebrights are often difficult to breed, and the inheritance of certain unique characteristics the breed carries has been studied scientifically. As a largely ornamental chicken, they lay tiny, white eggs and are not kept for meat production. H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
