Ciencias Veterinarias. Benjamin Franklin , Circuito Pronaf, , Cd. Poultry farmers in the southeastern of Mexico consider that the productivity of the hens that comes from rearing on floor has a higher productive performance than reared hens in cages, mainly due to higher percentage of egg laying and lower mortality. The aim of this study was to evaluate the productive performance of the laying hen in relation to the type of rearing. A total of pullets Bovans White of 17 weeks of age were housed in cages with five pullets cage -1 cm 2 pullet
A total of pullets Bovans White of 17 weeks of age were housed in cages with five pullets cage -1 cm 2 pullet But the disadvantage comes in that flocks of each of the two parent breeds must be maintained in order to have birds with which to make the cross to produce the sex-link chicks. Pullets reared on the floor were illuminated with fluorescent lamps of 15 W, reared in housings with dimensions of 10x75 Sex characteristics of white leghorn chickens, where pullets by housing were kept to have an initial density of 16 pullets m -2 cm 2 pullet Services on Demand Journal. If the hen carries the silver gene, then the daughters will be barred and the sons white or white with barring. The two chalazae are Tracy akali to the chalaziferous layer of albumen around the yolk and one to each pole of the egg and anchored in the dense albumenous sac or outer thick albumen. Folic acid mg 0.
Sex movtes videos. Services on Demand
Babe breast giant edited: Mar 3, I love to see my chickens scratching in the dirt for worms, sunbathing, stretching their legs and enjoying life — and I love the gift of their beautiful eggs for my family to eat! HELP chickenx The most common illnesses an older hen could have, includes caged layer fatigue, rickets, egg Sex characteristics of white leghorn chickens, and fatty liver syndrome. Oct characteristlcs, Post 10 of Poultry Club of Great Britain. From Wikipedia, the free encyclopedia. As such Leghorns were used to breed most of those other chicken breeds. Or, post pictures and ask. They tend to be average sized chickens and also tend to be quite interesting characters.
Genetic parameters for egg and related characteristics of White Leghorn hens in a subtropical environment 1.
- Other Fowl.
- Raising chickens can be fun and educational for the entire family.
- There are all different kinds of chicken breeds throughout the country and around the world.
- BackYard Chickens.
- Leghorn chicken is a Mediterranean chicken breed originating in rural Tuscany, in central Italy.
Incubation period, Chromosome numbers and age at sexual maturity of different species of poultry. Kadaknath, Naked neck, chittagong. There are only four pure Indian breeds of chicken are available. They are, Aseel, Chittagong, Busra and Kadaknath. They are the actual commercial-type of chicken used for egg or meat production since they are high laying or fast growing. These birds possess high degree of heterosis or hybrid vigour. The type of comb is usually a breed or variety characteristic.
The comb type is the result of gene interaction but the comb size is associated with gonadal development and intensity of light under which they are grown.
Some of the types of combs are,. It consists of a blade surmounted by spikes. The lower solid portion being the blade and the spaces between the spikes are called serrations. It differs in size, shape and number. The number of serrations varies according to breeds. The gene for single comb is recessive to the gene for Rose and Pea comb.
The middle one is being the highest than others. It is very well seen on the head of a well-bred Brahma. It varies in length and width according to breed. It is relatively small in size and has irregular grooves on the surface.
Malays breed. The comb starts just above the beak and from it branches into two spikes, thick at the base and tapered at the end. Houdans breed. It is having a slight furrow transversely across the middle. Silkie breed. Sicilian Buttercup breed. Need for handling of chicken. Handling of chicken First, bird is to be caught from the flock in case of deep-litter system or to be taken out from the cage before it is handled for any of the above-operations. While catching bird on deep-litter, it is to be caught either by putting catching hooks to the leg or simply by grabbing the legs with fingers.
Birds should never be caught by neck or feathers, which can put birds under severe stress or discomfort. For holding bird for some time before starting of actual operation, it can be held at wings or its movement can be restricted or stopped by entangling their wings to each other at the base.
While taking out bird from cage, head with neck should be taken out first by holding body of birds in both the hands with closure of wings to facilitate easy removal of bird from cage, without causing any injury to bird. The same procedure is followed while putting bird in cage i. To hold the bird for examination, abdomen of bird should rest on palm of one hand by grabbing two legs of bird between fingers, facing head of bird towards examiner; keeping one hand free for examination.
The examination is done by gentle handling with minimum stress to prevent struggling. The yolk is not the true reproductive cell, but a source of food material from which the minute cell blastoderm and its resultant embryo partially sustain their growth. When the pullet reaches sexual maturity, the ovary and the oviduct undergo many changes. About 11 days before laying first egg, a sequence of hormonal changes occur. The follicle-stimulating hormone FSH produced by the anterior pituitary gland causes the ovarian follicles to increase in size.
In turn, the active ovary begins to generate hormones, viz. Higher blood plasma levels of estrogen initiate development of the medullary bone, stimulate yolk protein and lipid formation by the liver and increase the size of the oviduct, enabling it to produce albumen proteins, shell membranes, calcium carbonate for shell formation and cuticle.
The yolk material is laid down adjacent to the germinal disc that continues to remain on the surface of the globular yolk mass. About 10 days are required for an individual yolk to mature. Deposits of yolk material are very slow at first and light in colour. The colour present in the yolk is xanthophylls , a carotenoid pigment derived from the diet. The pigment is transferred first to the bloodstream, then quickly to the yolk.
More carotenoids are deposited when the extending out from the yolk, are formed as the egg is rotated in the lower portions of the oviduct. Twisted in opposite directions, the chalazae tend to keep the yolk centered in the egg after it is laid. Shell membrane formation. The shell membranes are added to the egg in the isthmus. These membranes are made up of many interlacing fibres and are somewhat permeable to both water and air.
Two membranes are formed, an inner and outer shell membranes. These are rather loose-fitting membranes when first formed. The outer shell membrane is about 3 times as thick as the inner one. The outer membrane is about 0. The membranes normally adhere to each other except at the large end of the egg, where they are separated to form the air cell.
The air cell is quite small when the egg is first laid but progressively increases in size as the egg cools and as water later escapes from the contents by evaporation through the membranes and the shell. Egg shell formation. The egg remains longest in the uterus or shell gland, where the eggshell is formed, which requires 19 to 20 hours. The shell is made up of almost entirely of calcium carbonate deposited on an organic matrix consisting of protein and mucopolysaccharide.
The shell membranes intimately bound the shell on the inside. The shell is embedded in the membranes by a structure known as the basal cap , a portion of cone layer, which is the innermost part of the shell. The major portion of the shell is made up of a palisade or column layer that is penetrated by numerous pores extending through the shell. The final layer of the shell is known as the cuticle, an organic material covering the surface of the egg.
The cuticle seals the pores and is useful in reducing moisture losses and in preventing bacterial penetration of the eggshell. Laying of the Egg Eggs are normally formed with small end first as they move down the oviduct. If the hen is not frightened, the egg will rotate horizontally just prior to oviposition the act of laying egg and will be expelled large end first.
However, if something disturbs the bird prior to rotation, the egg will be laid quickly and forced through the vent small end first.
Structure of Egg The egg has four main parts namely 1 yolk, 2 Albumen, 3 Shell membranes and 4 Shell. The two chalazae are attached to the chalaziferous layer of albumen around the yolk and one to each pole of the egg and anchored in the dense albumenous sac or outer thick albumen.
The yolk is enclosed in a colourless membrane called vitalline membrane. Latebra is in the centre of the yolk, which is a small and nearly circular score of light coloured fluid, which does not completely harden on boiling. During the formation of yolk, concentric rings of yolk material are laid down, in alternate light and dark yellow layers, one layer for each day of yolk formation.
Germinal disc is the reproductive cell present on the surface of the yolk. If fertilized the germ cell is then called as blastoderm and if not it is called as blastodisc. The albumen is a protection for the blastoderm. It keeps blastoderm from coming in contact with the shell and lessens the force of jarring. Another function of the albumen is to prevent the entrance of bacteria to the yolk or germ cell.
The outer is attached to the shell and the inner is loosely attached to the outer albumen layer and encloses the egg contents. The shell membranes allow transmission of gases to and from the egg contents.
The shell colour is characteristic of breed that may be white, brown or green. Brown colour is due to the presence of a pigment called Oophorphyrin. Biliverdin pigment is responsible for the Green Colour of eggs produced by Auracana breeds. The half of the carbohydrates present in albumen is as free glucose and half as glycoproteins. In dried egg products, glucose interacts with other egg components to produce off-colours and off-flavours during storage.
In order to avoid this problem, the glucose is eliminated by enzymatic digestion just before the drying process. Pigments of Chicken Egg Egg pigments are distributed in all parts of egg. Yolk contains high quantity of pigments. The yolk pigments are classified based on its solubility as lipochrome fat soluble and lyochrome water soluble. Lipochromes are group of carotenoids carotene and xanthophylls.
The albumen contains one pigment called ovoflavin. Expert System for Poultry. Home About Us Contact Us. General Informations About Poultry. Bird Chicken J. Ovalbumin Ovotransferrin Conalbumin Ovomucoid Ovoglobulins 8. Ovomucin 3. Lysozyme 3.
The rooster's comb took off like crazy even when it was still yellow then turned red. Commercially raised Leghorns are kept in small battery cages and never see sunshine. There are all different kinds of chicken breeds throughout the country and around the world. Look like rooster? A good breeder should be happy to set you confidently on your way.
Sex characteristics of white leghorn chickens. Leghorn Chicken Characteristics
Genetic parameters for egg and related characteristics of White Leghorn hens in a subtropical environment 1. Hani M. Sabri 2 , Henry R. Wilson 3 , Robert H. Harms 3 and Charles J. Send correspondence to C. Fax: , E-mail: wilcox dps. Estimates of heritability and phenotypic and genetic correlations between egg number, weight, specific gravity, mass, and estimated shell weight were obtained, along with phenotypic and genetic correlations of specific gravity and weight with body weight, weight change, metabolizable energy intake, residual feed consumption, and weight and age at sexual maturity.
Data were from White Leghorn hens by 50 sires and dams. Heritabilities of the egg traits ranged from 0. Their standard errors ranged from 0. Phenotypic correlations ranged from 0. The highest phenotypic and genetic correlations were between egg number and mass. Genetic correlations for specific gravity and estimated shell weight were, with body weight, Results should contribute to the design of efficient selection programs for economically important traits in hens.
Egg shell quality embodies characteristics such as shell thickness, shell weight, egg specific gravity, shell strength, resistance to breakage, texture, color, etc. In order to study egg shell problems or to select for changes in egg shell characteristics, reliable measurement techniques to define shell characteristics must be available.
Measurements such as shell thickness and shell puncture pressure result in destruction of the egg and permit only one measurement per egg. Other tests, such as egg specific gravity, beta-particles and ultrasound, do not destroy the egg and multiple measurements can be obtained.
The importance of shell quality, various techniques for evaluating shell quality, and effective utilization of techniques involved have been reviewed by several authors, including Farnsworth and Nordskog , Carter , Nagai and Gowe a,b , Perek and Snapir , Rodda , Potts and Washburn , , Potts et al. Most methods used have been capable of distinguishing differences in shell quality due to breed, strain and individual birds. However, most breeding programs put little selection pressure on shell quality, possibly because of the risk of diverting selection pressure away from egg production, egg weight, and other traits Hunton, , as well as the lack of an effective, non-destructive, evaluation procedure.
Measurement techniques that can be made early in the production period of the hen are most useful to the breeder, and this seems to be feasible for shell quality evaluations Nagai and Gowe, a,b. The effectiveness of each technique may vary among breeds and strains tested Potts et al. Egg specific gravity, with appropriate corrections, has been found to be an acceptable estimator of shell quality Wells, ; Potts and Washburn, ; Potts et al.
When taking heritability, genetic correlations and ease of measurement of different shell quality traits into consideration, specific gravity has been the best shell quality trait to use in selection programs Grunder et al. However, egg weight is important in determining egg specific gravity, and the two traits are negatively correlated.
Abdallah et al. Harms et al. The formulas later were modified to increase accuracy and sensitivity of estimates Harms et al. Objectives of the current study were to estimate genetic parameters for various characteristics of hens and eggs, so that efficient multi-trait selection programs can be developed which will maximize economic return.
The data used in this study were collected in conjunction with studies reported earlier by Sabri and Sabri et al. Hens were distributed randomly in three rows of individual cages.
Water and food were available ad libitum. A standard layer diet Data were obtained during seven 4-week periods 26 to 29, 30 to 33, 34 to 37, 38 to 41, 42 to 45, 46 to 49, and 50 to 54 weeks of age. Eggs were collected and weighed daily and were used to calculate the average EW for each period. SG was measured twice per week on the day of lay. SG for each hen was represented by the average of SG for each period. SG was measured using procedures of Voisey and Hamilton with increments of 0.
Data were analyzed by the method of ordinary least squares analysis of variance using the computer programs of Harvey Mathematical model included period, sire and dam in sire. Period effects were considered fixed and the remaining effects were considered random. Heritability was estimated as:. All changes with age were statistically significant. Weighted regression analyses of period effects Table I indicated a linear decline in SG of 0. The trend was to increase over time for EW but to decrease in the other response variables.
The decrease in SG after peak egg production and the increased EW with increased age have been previously reported for example, see Abdallah et al. Period effects were included in subsequent analyses of genetic and phenotypic parameters. Heritabilities estimated using data from all periods for egg traits were moderate Table II. These values generally agreed with those of several others, e. Heritabilities for period 1 early were higher, although not differing statistically, than for period 7 late for EN, SG and SWe, with an increase in the standard error of the estimates with increased age.
This agreed with Grunder et al. They stated that estimates were almost always higher when measured early compared with late in the laying year. Hagger and Abplanalp and Sabri et al. They suggested that the genetic potential of egg production and related traits are well expressed at peak egg production, which minimized effects of environmental factors compared to later times of the laying year.
Higher heritabilities at early stages of the laying year are advantageous because early selection decisions can be made. Phenotypic correlations of both SG and SW with economic traits were low. These agreed in sign and generally in value with those of other workers Muir and Patterson, ; Abdallah et al. Grunder et al. According to Abdallah et al. The negative genetic correlation between EN and SG agreed in sign with those reported by several, for example Grunder et al.
Genetic correlations between SG and some economically important traits generally were low in value, except the correlation with SMAGE of They concluded that genetic correlations with SG were such that they would allow improvement in percentage intact egg without seriously compromising selection objectives for other traits.
These authors suggested that SG would be the best egg shell quality trait for a selection program. SG and SWe are traits that are easily measured, and multiple measurements are possible if desired. They have the additional advantage that the egg is not destroyed. However, care should be taken to control solution and egg temperature when measuring SG.
The use of SG increments of 0. Sensitivity and accuracy can also be improved by adjusting for changes in the density of egg contents due to age of the hens Sloan et al.
The results of this study also suggest the potential for using early measurements of SWe in selection programs, which has definite advantages to breeders Hagger and Abplanalp, ; Sabri et al. However, negative genetic correlations of SG with EW and EM would suggest that SWe has greater potential for use in breeding programs for improving egg shell quality and as an indicator of the hen's ability to metabolize and secrete calcium and other egg shell components.
The authors gratefully acknowledge Rafael M. Roman for statistical analyses of time trends. A herdabilidade dos caracteres dos ovos variou de 0,20 a 0,55, aumentando com a idade da ave de 26 a 54 semanas. Abdallah, A. Various methods of measuring shell quality in relation to percentage of cracked eggs.
Effect of age and resting on hens laying eggs with heavy or light shell weight. The hen's egg: estimation of egg mean and flock mean shell thickness. Breeding for egg quality.
Genetic differences in shell characteristics and other egg quality factors. Genetic parameters of egg shell quality traits and percentage of eggs remaining intact between oviposition and grading. Correlations between measures of eggshell quality or percentage of intact eggs and various economic traits.
Food consumption records for the genetic improvement of income over food costs in laying flocks of White Leghorns. Methods and factors that affect the measurement of egg shell quality.
Relationship between egg shell quality and shell breakage and factors that affect shell breakage in the field - a review.
World's Poult. A method for estimating shell weight and correcting specific gravity for egg weight in eggshell quality studies. Errors in measuring and calculating eggshell quality.
Mimeo Rpt. Genetic factors affecting egg shell quality. Genetic and environmental associations of uncollectible egg production with shell quality, rate of lay, and erratic timing of oviposition in White Leghorn hens.
Genetic control of egg quality. Sources of variation. Selection for maximum rate of improvement. Non-destructive measurements of egg parameters and quality characteristics. Interrelationships between shell quality and egg production and egg and shell weights in White Leghorn and White Rock hens.
Shell evaluation of white and brown egg strains by deformation, breaking strength, shell thickness and specific gravity. Relationship to egg characteristics.