Japanese quails () show keel bone damage during the laying period-a radiography study.

Keel bone damage is an important welfare issue in laying hens and can occur with a high prevalence of up to 100% of hens within one flock. Affected hens suffer from pain. Although multiple factors contribute to the prevalence and severity of keel bone damage, selection for high laying performance appears to play a key role.

Productive performance, perching behavior, keel bone and other health aspects in dual-purpose compared to conventional laying hens.

Several alternatives to avoid killing male day-old chicks are available. One of these alternatives is to keep dual-purpose chicken strains. The aim of this study was to compare dual-purpose hens (Lohmann Dual, LD) with conventional laying hens (Lohmann Tradition, LT) in terms of performance, animal welfare parameters such as keel bone state and foot pad dermatitis, and perching behavior.

A tagged visual analog scale is a reliable method to assess keel bone deviations in laying hens from radiographs.

Laying hens often suffer from keel bone damage (KBD) that includes pathologies with different etiologies, like diverse forms of fractures and deviations. Since KBD is a problem in all countries and housing systems, methods for the assessment of deviations are urgently needed. Comparisons between genetic lines and between studies are important to detect underlying mechanisms.

Estradiol-17ß Is Influenced by Age, Housing System, and Laying Performance in Genetically Divergent Laying Hens ( f.d.).

The estrogen estradiol-17ß is known as one of the major gonadal steroid hormones with different functions in reproduction. In this study we analyzed estradiol-17ß concentration in laying hens of four pure bred chicken laying lines at four different time intervals of the laying period (17th-19th week of age, 33rd-35th week of age, 49th-51st week of age, and 72nd week of age). The high performing white egg (WLA) and brown egg (BLA) layer lines as well as the low performing white (R11) and brown (L68) layer lines were kept in both single cages and a floor housing system.

Video Endoscopy-Guided Intrabronchial Spray Inoculation of in Goats and Comparative Assessment of Lung Lesions With Various Imaging Methods.

Bovine tuberculosis (bTB) not only poses a zoonotic threat to humans but also has a significant economic impact on livestock production in many areas of the world. Effective vaccines for humans, livestock, and wildlife are highly desirable to control tuberculosis. Suitable large animal models are indispensable for meaningful assessment of vaccine candidates.

Bone quality and composition are influenced by egg production, layer line, and oestradiol-17ß in laying hens.

Keel bone fractures are a serious animal welfare problem in laying hens. The aim of the current study was to assess the influence of egg production, oestradiol-17ß, and selection for high laying performance on bone quality. Hens of two layer lines differing in laying performance (WLA: 320 eggs per year, G11: 200 eggs per year) were allocated to four treatment groups.

Investigation of the Morphology of Adrenal Glands in Hens Kept in Two Different Housing Systems-A Pilot Study.

It is difficult to objectively assess the chronic effects of housing systems on livestock and particularly on laying hens. However, this seems to be important in the context of animal welfare. Therefore, we conducted the present study in order to compare the effect of two different housing conditions, single cage (SC) and floor pen (FP), on the morphology of the adrenal gland.

Influence of Age and Phylogenetic Background on Blood Parameters Associated With Bone Metabolism in Laying Hens.

The high laying performance of today's laying hens places enormous demands on their mineral metabolism. While up-to-date data are rare, the present study aimed to describe blood parameters associated with egg laying and bone metabolism during the pre-laying period, in the course of the laying period and the daily egg laying cycle. Ten to 15 laying hens of two high-performing, phylogenetically divergent lines (BLA: brown-egg layer; WLA: white-egg layer), kept in single cages were blood sampled at 17, 25, 29, 49, and 69 weeks of age.

Bone Health or Performance? Adaptation Response of Genetically Divergent Chicken Layer Lines to a Nutritive Calcium Depletion.

In modern laying hybrids, calcium (Ca) homeostasis is immensely challenged by daily eggshell calcification. However, excessive mobilization of Ca from bones may lead to osteoporosis, which then manifests in a high incidence of poor bone quality. The aim of this study was to characterize the hens' adaptation response to an alternating dietary Ca restriction.

Explanations for keel bone fractures in laying hens: are there explanations in addition to elevated egg production?

The current article served to provide the most up-to-date information regarding the causes of keel bone fracture. Although elevated and sustained egg production is likely a major contributing factor toward fractures, new information resulting from the development of novel methodologies suggests complementary causes that should be investigated. We identified 4 broad areas that could explain variation and increased fractures independent of or complementing elevated and sustained egg production: the age at first egg, late ossification of the keel, predisposing bone diseases, and inactivity leading to poor bone health.

Smaller brains in laying hens: New insights into the influence of pure breeding and housing conditions on brain size and brain composition.

During domestication, many different chicken breeds have been developed that show many alterations compared with their wild ancestors and large variability in parameters such as body size, coloring, behavior, and even brain morphology. Among the breeds, one can differentiate between commercial and noncommercial strains, and commercial strains do not usually show variability as high as noncommercial breeds but exhibit a high production rate of eggs (or meat). The breeding of high-performing laying hens, including the housing conditions of hens, is often a focus of concern for animal welfare, and to date, little is known about the correlation between housing conditions and artificial selection on brain structure.

The Role of Egg Production in the Etiology of Keel Bone Damage in Laying Hens.

Keel bone fractures and deviations belong to the most severe animal welfare problems in laying hens and are influenced by several factors such as husbandry system and genetic background. It is likely that egg production also influences keel bone health due to the high demand of calcium for the eggshell, which is, in part, taken from the skeleton. The high estrogen plasma concentration, which is linked to the high laying performance, may also affect the keel bone as sexual steroids have been shown to influence bone health.

Comparison of cortisol concentrations in plasma and saliva in dairy cattle following ACTH stimulation.

The experiments described in this research communication compared cortisol concentrations in plasma and saliva samples collected from dairy cattle before and after an adrenocorticotropic hormone (ACTH) application. For that purpose, blood and saliva samples were collected from five dairy cows at determined time intervals before (490 min and down to 0 min) and after (10 min and up to 500 min) an ACTH application. Mean baseline cortisol concentrations were greater in plasma compared to saliva.

Influence of a Sustained Release Deslorelin Acetate Implant on Reproductive Physiology and Associated Traits in Laying Hens.

The aim of this study was to develop an animal model with non-laying hens which would allow for investigation of the relationship between egg production and common diseases in hens. A total of 40 Lohmann Selected Leghorn hens were kept for 20 weeks in a floor housing system in two groups: group "Adult" (21 weeks of age) and group "Juvenile" (14 weeks of age). In each group, 10 hens were administered a 4.

Radiographic examination of keel bone damage in living laying hens of different strains kept in two housing systems.

A high prevalence of deviations and fractures of the keel bone is a widespread welfare problem in laying hens. The aim of this study was to experimentally investigate this multifactorial problem throughout the laying period and to compare the prevalence and severity in different layer lines and different housing systems. High performing white (WLA) and brown (BLA) pure bred layer lines and low performing white (R11, G11) and brown layer lines (L68) were kept in both single cages and a floor housing system.

Effects of intra-hippocampal D-AP5 injections on one trial passive avoidance learning in adult laying hens (Gallus gallus domesticus).

Domestic chickens are an established model organism for studies on learning and memory. Commonly, the chicks are used as subjects in several different learning tests, including one trial learning tests. However, for adult laying hens no such one trial learning tests have been established.