Conventional Cages Research Articles

Impact of Different Rearing Systems and Age on Bovans White Layer’s Performance, Egg Quality Traits and Synthesis of Heat Shock Protein 70 kDa

Abstract This study was conducted to investigate the performance of laying hens and to determine possible age-related changes on external and internal quality traits of their eggs and synthesis of heat shock protein 70 kDa (HSP70) in the conventional cage and organic rearing systems. For this purpose, 4 different Bovans White hybrid flocks of the same age were monitored in each of these two systems for 52 weeks. While a total of 360 eggs were examined to determine the effects of rearing system and age (30 and 60 weeks) on egg quality traits, 48 liver tissue samples were examined for the analysis of HSP70. Egg production (hen-day) and dirty egg ratio were higher in the organic rearing system (P<0.05). The age at 50% yield, the age at peak of lay, and peak production rate were calculated as 156, 218.75 days and 95.98% in the conventional system, and 155.75, 201.50 days, and 96.56% in the organic system, respectively (P>0.05). While egg weight, albumen weight, yolk weight, shell weight, shape index, and yolk colour were higher in the organic system, the crude ash ratio of eggshell and shell ratio were higher in the conventional system (P<0.05). It was also found that the egg weight, albumen weight, yolk weight, shell weight, and the percentage of yolk were higher at 60 weeks of age (P<0.001). The percentage of shell and albumen, shape index, and yolk colour were higher at 30 weeks of age (P<0.001). The interactions between rearing system and age were statistically significant in terms of shell thickness, shape index, crude ash ratio, and yolk colour (P<0.001). Stress protein (HSP70) level was affected only by the rearing system and was higher in the organic system (P<0.001). As a result, the organic system can be considered as advantageous in terms of egg production and quality traits and the eggs of young hens exhibited better properties. The high level of HSP70 in the organic system could indicate that hens were affected by the environmental conditions at higher rates and/or the hens reared in the organic system had a stronger antioxidant defence system.

Consumer perceptions of egg-laying hen housing systems.

The egg industry has transitioned, or is in the process of transitioning, from conventional cages to alternative hen housing systems in response to legal changes in many states across the United States (US). However, consumers find it is increasingly difficult to understand the details behind those labels and specific attributes conveyed. There are multiple hen housing options with a wide range of costs and impacts on hens, workers, and the environment. This research furthers the understanding of US public perceptions and attitudes related to hen housing systems and corresponding animal welfare, worker, economic, and environmental effects. Results reveal that the US public perceives cage-free aviaries as achieving essentially the same positive impact on hen health and stress, hen behavior, and environmental impact as free-range systems when compared to conventional cage systems. The information provided can assist industry, marketing, and policy decisions with respect to hen housing.

Technical note: Assessment of the better location of gnawing sticks in growing rabbit cages

<p>The present work tries to determine the best location of wooden sticks for environmental enrichment, considering usage and level of contamination as variables. A total of 540 rabbits at 4 wk of age were caged in 60 groups of nine animals in conventional rabbit cages, and the effect of the allocation of wooden sticks was studied by fixing them on the floor in 30 cages and on the cage ceiling in the other 30 cages. The sticks were sampled during the fattening period (5 wk) to evaluate the contamination of the sticks, with detection of the most common faecal indicator bacteria in rabbit production (<em>E. coli</em> and <em>Clostridium</em> spp.). Likewise, quantitative enumeration analyses for <em>E. coli</em> were performed at the same sampling times for detection of both bacteria. Sticks used for environmental enrichment of the cage in this experiment were made of fir (<em>Picea abies</em>). According to the results, placing the wooden stick on the ceiling instead of the floor reduces stick consumption (6.28±1.75 <em>vs.</em> 13.55±1.75% of stick consumed). Moreover, microbiological analyses revealed that wooden sticks placed on the ceiling were less contaminated than those placed on the floor (2.8 and 22.8% for <em>E. coli</em>, respectively and 1.1 and 10.6% for <em>Clostridium</em> spp., respectively). In conclusion, fixing the sticks on the ceiling of the cage was revealed as a safer choice during most weeks of the growing period.</p>

An enriched environment prevents diabetes-induced cognitive impairment in rats by enhancing exosomal miR-146a secretion from endogenous bone marrow-derived mesenchymal stem cells.

Increasing evidence suggests that an enriched environment (EE) ameliorates cognitive impairment by promoting repair of brain damage. However, the mechanisms by which this occurs have not been determined. To address this issue, we investigated whether an EE enhanced the capability of endogenous bone marrow-derived mesenchymal stem/stromal cells (BM-MSCs) to prevent hippocampal damage due to diabetes by focusing on miRNA carried in BM-MSC-derived exosomes. In diabetic streptozotocin (STZ) rats housed in an EE (STZ/EE), cognitive impairment was significantly reduced, and both neuronal and astroglial damage in the hippocampus was alleviated compared with STZ rats housed in conventional cages (STZ/CC). BM-MSCs isolated from STZ/CC rats had functional and morphological abnormalities that were not detected in STZ/EE BM-MSCs. The miR-146a levels in exosomes in conditioned medium of cultured BM-MSCs and serum from STZ/CC rats were decreased compared with non-diabetic rats, and the level was restored in STZ/EE rats. Thus, the data suggest that increased levels of miR-146a in sera were derived from endogenous BM-MSCs in STZ/EE rats. To examine the possibility that increased miR-146a in serum may exert anti-inflammatory effects on astrocytes in diabetic rats, astrocytes transfected with miR-146a were stimulated with advanced glycation end products (AGEs) to mimic diabetic conditions. The expression of IRAK1, NF-κB, and tumor necrosis factor-α was significantly higher in AGE-stimulated astrocytes, and these factors were decreased in miR-146a-transfected astrocytes. These results suggested that EEs stimulate up-regulation of exosomal miR-146a secretion by endogenous BM-MSCs, which exerts anti-inflammatory effects on damaged astrocytes and prevents diabetes-induced cognitive impairment.

Effects of rearing systems on reproductive hormones secretion and their receptors gene expression in Xianju chickens under summer conditions.

Previous study in our lab showed that indigenous Xianju chickens from free-range system (FRS) under summer conditions had lower egg production than those from conventional cage rearing system (CRS). The objective of this study was to preliminarily determine the FRS-dependent mechanism of depressing laying performance according to determining the effect of rearing systems on reproductive hormones secretion and their receptors mRNA expression in Xianju chickens reared under summer conditions. A total of 360 indigenous Xianju chickens were randomly allocated to CRS and FRS groups, each of which included 5 replicates of 36 hens. The experiment lasted between 21 and 29 wk of age. We found that the ovarian weight, numbers of small yellow follicles, and large white follicles in the FRS group were lower than those in the CRS group (P < 0.05). Changing from CRS to FRS increased serum concentrations of prolactin and decreased serum-luteinizing hormone and progesterone levels (P < 0.05). Gene expressions in the preovulatory follicles from FRS hens were upregulated for prolactin receptor and downregulated for luteinizing hormone receptor and progesterone receptor, compared to those from CRS hens (P < 0.05). It can be concluded that changing from CRS to FRS in the current experimental conditions depressed egg production traits in Xianju chickens by inducing a synergistic activity of reproductive hormones and the gene expressions of their receptors.

Developments of nano-TiO2 incorporated hydroxyapatite/PEEK composite strut for cervical reconstruction and interbody fusion after corpectomy with anterior plate fixation

The technique of anterior cervical corpectomy and fusion (ACCF) for strut grafting has become a widespread and actively applied for many cervical complaints including cervical degeneration of the intervertebral disks, cervical trauma, cancer, rheumatoid arthritis and multilevel cervical spondylotic diseases. To avoid the complications of the old techniques, the construct stability and long anterior screw-plate designs of the bone strut have been improved by using effective biomaterials. The nanostructured hydroxyapatite (HAp) incorporated with biocompatible polymer matrixes is an effective biomedical material and creating a functional properties applied for different tissue replacements such as dental, hips, knees, tendon and ligaments and tissue repair for maxillofacial reconstruction, stabilization of the jaw bone and spinal fusion. In the present investigation, we have successfully designed cylindrical nano titanium dioxide (n-TiO2) interbody fusion with anterior plate fixation. The n-TiO2 incorporated HAp/ Polyetheretherketone (PEEK) nanocomposite strut has a superior mechanical properties and larger contact area with high fusion rates as compared with the HAp/PEEK strut in the absence of n-TiO2 nanoparticles. It is highly able to provide appropriate strength and biological activity similar to the conventional titanium cage and also mainly it has been minimizes subsidence value. The synthesized novel material of n-TiO2 incorporated HAp/PEEK nanocomposite strut is scientifically given effective outcomes for fusion and reconstruction of the ACCF.

Prevalence, Persistence, and Antimicrobial Resistance of Campylobacter spp. from Eggs and Laying Hens Housed in Five Commercial Housing Systems.

Husbandry practices for laying hens in commercial egg production is a topic of interest from a social, economic, and regulatory standpoint. Animal welfare concerns regarding the use of conventional cages have arisen and consumer perceptions of hen welfare have led to a higher demand for cage-free eggs. The aim of this study was to assess the impact of housing systems on prevalence, persistence, and antimicrobial resistance (AMR) of Campylobacter from laying hens and shell eggs. A total of 425 samples were collected over a 10-month period from the North Carolina Layer Performance and Management Test and Campylobacter isolates were identified by serological, biochemical, and molecular tests. Genetic variability was evaluated using pulsed-field gel electrophoresis (PFGE) and AMR testing was performed. Prevalence of Campylobacter spp. ranged from 11.1% in the enrichable cages to 19.7% in the conventional systems. A greater prevalence of Campylobacter was found in the fecal swab samples from free-range birds compared with those of birds housed in the more intensive housing systems (p > 0.05). Overall, 72 isolates were confirmed as Campylobacter spp. by PCR. More than 90% of the isolates (n = 66) were identified as Campylobacter jejuni, followed by Campylobacter coli (n = 6). C. jejuni isolates displayed high levels of resistance to tetracycline (67%). Genetic variability of Campylobacter was high, with more than 20 PFGE patterns identified. Pattern "a" comprised 42% of isolates from all housing systems and was also the most persistent. This study suggests that housing systems of laying hens used for commercial shell egg production may impact the rate of Campylobacter shedding by layers. Isolation rates and tetracycline resistance levels of this pathogen are still of concern, emphasizing the need for well-implemented biosecurity measures on the farm.

A Description of Laying Hen Husbandry and Management Practices in Canada.

Simple SummaryFurnished cage and non-cage (single-tier or multi-tier) housing systems are increasingly used worldwide in efforts to improve laying hen welfare. Canadian laying hen farms are undergoing a similar transition, however, little is known about the housing and management of laying hens in these housing systems in Canada. Data collected through farmer questionnaires from 65 laying hen flocks across Canada revealed commonly used management practices in furnished cage (26), single-tier (17) and multi-tier systems (22). Non-cage systems should allow hens to perform natural behavior (e.g., foraging/dustbathing). However, a proportion of non-cage systems either did not provide litter or considered manure as a litter substrate, which could have implications for consumer perspectives on these systems. Daily flock inspections and vaccination schemes were the main practices used to maintain flock health, whereas veterinarian involvement on-farm and in the development and implementation of a flock health plan was less common. Further research is needed to make clear recommendations and to investigate how to facilitate management changes by farmers currently transitioning to furnished cage and non-cage housing systems.Canadian laying hen farms are transitioning from conventional cage housing to furnished cage and non-cage housing systems to improve laying hen welfare. However, little is known about the current housing and management systems in Canada. This study addresses this knowledge gap by describing different housing and management practices used on farms where laying hens were housed in furnished cages or non-cage housing systems. A questionnaire covering farm and housing conditions, litter management, nutrition and feeding, environmental control, flock characteristics, rearing and placement, health, egg production and performance were distributed through provincial egg boards to 122 producers across Canada. Data were collected from 65 laying hen flocks (52.5% response rate) in 26 furnished cage, 17 single-tier and 22 multi-tier systems. Flocks were on average 45.1 ± 14.59 weeks old (range: 19–69 weeks). Frequencies of different management practices were calculated according to housing system. Most flocks were reared in the same housing system as they were housed in during lay, with the exception of furnished cage layers which were reared in conventional cage systems. Results indicated that a large proportion of non-cage systems were either fully slatted or had manure as a litter substrate, which could have implications for consumer perspectives on these systems. Further research is needed to develop clear recommendations on proper litter management for farmers. In general, flock health was managed through daily inspections and vaccination schemes, whereas veterinarian involvement on-farm was less common. Vaccination, hygiene, and effective biosecurity should be maintained to ensure good health in laying hens in furnished cage and non-cage systems during the transition to these systems.

Egg production and quality responses of adding up to 7.5% defatted black soldier fly larvae meal in a corn–soybean meal diet fed to Shaver White Leghorns from wk 19 to 27 of age

We examined egg production and quality responses of adding up to 7.5% defatted black soldier fly larvae meal (BSFLM) in a corn–soybean meal diet fed to pullets (19 to 27 wk of age). The concentration of CP and crude fat in BSFLM sample was 59.3 and 7.0% DM, respectively. A corn–soybean meal diet was formulated with 0 or 5.0 or 7.5% BSFLM and fed (n = 6) to a total of 108, 19-wk-old Shaver White pullets placed in conventional cages (6 birds/cage). The birds had free access to feed and water. Hen-day egg production (HDEP) and average egg weight were monitored daily and feed intake (FI) weekly. Egg quality parameters were assessed on individual eggs collected on the 5th d of wk 22, 24, and 26 and included individual EW (IEW), albumen height (HU), yolk color (YC), egg shell-breaking strength (SBS) and thickness (ST). A quadratic response (P < 0.02) was observed for HDEP, EW and egg mass. Specifically, birds fed 0 and 7.5% BSFLM diets had similar (P > 0.05) values for these parameters with birds fed 5.0% BSFLM showing lower (P < 0.05) HDEP than 0 or 7.5% BSFLM fed birds. The HDEP was 89.4, 84.8, and 87.8 for 0, 5.0, and 7.5% BSFLM, respectively. Feeding BSFLM linearly (P < 0.01) increased FI and feed conversion ratio (FCR) (FI/egg mass). There was no diet effect (P > 0.05) on IEW and HU, however, BSFLM linearly (P = 0.02) reduced CV of IEW. The IEW was 53.7, 52.3, and 53.0 g for 0, 5.0, and 7.5% BSFLM-fed birds, respectively and corresponding CV values of IEW were 7.9, 5.2, and 5.1%. Feeding BSFLM linearly (P < 0.01) increased YC, SBS, and ST. In conclusion, birds fed 7.5% BSFLM had similar HDEP and egg mass but poor FCR relative to corn–soybean meal diet without BSFLM. The effects of BSFLM on egg quality characteristics warrant further investigations.

Effects of production systems on the carcass and meat quality characteristics of spent laying hens.

This study evaluated the carcass characteristics and meat quality attributes of spent laying hens raised under conventional battery cage and free-range systems. Thirty free-range and 30 conventional battery-caged Lohmann Brown-Elite spent laying hens of 53 and 40 wk of age, respectively were obtained from a commercial egg producer. Carcass, portion, and organ weights and percentages were determined. Physicochemical analyses were performed on thigh and breast meat samples. Caged hens had heavier (P ≤ 0.05) warm and cold carcasses, thighs, wings, and feet. The percentages of the breast (26.1 ± 0.51vs. 28.3 ± 0.28), drum, breast bones, breast thaw and cooking loss, and thigh cooking loss were higher (P ≤ 0.05) for free-range than for caged hens. Free-range hens had heavy (P ≤ 0.05) gizzards (33.9 ± 1.04vs. 30.5 ± 0.73) and bones and a lower (P ≤ 0.05) breast meat percentage (47.3 ± 0.94vs. 51.7 ± 1.35). Meat redness (a*) (0.54 ± 0.222vs. 1.40 ± 0.135) and hue angle, skin redness (a*), breast (12.37 ± 0.411vs. 17.10 ± 0.751), and thigh (29.68 ± 0.306vs. 39.75 ± 0.826) Warner-Bratzler shear force values (N), breast moisture, and thigh ash content were higher (P ≤ 0.05) for free-range hens. Caged hens had a higher (P ≤ 0.05) thigh thaw loss percentage and breast ash content. Production system significantly influenced the carcass characteristics and meat quality of spent laying hens. The results of this study supply baseline information for the utilization of spent laying hens by the poultry industry and consumers.

Comparison of Anterior Cervical Discectomy and Fusion With a Stand-Alone Interbody Cage Versus a Conventional Cage-Plate Technique: A Systematic Review and Meta-Analysis.

Study Design:Systematic review and meta-analysis.Objective:Compare the clinical and radiographic outcomes of anterior cervical discectomy and fusion (ACDF) with a stand-alone interbody cage versus a conventional cage and anterior cervical plate technique.Methods:A systematic Medline search was conducted using PubMed, EMBASE, and Cochrane Library Database of Systematic Reviews. Search terms included “anterior cervical discectomy and fusion,” “cage,” and “bone plates,” or variations thereof. Only studies involving a direct comparison of ACDF with a stand-alone cage versus a cage and plate were included. From the selected studies, we extracted data on patient demographics, comorbidities, surgical risk factors, and pre- and postoperative radiographic findings. A meta-analysis was performed on all outcome measures. The quality of each study was assessed using the Downs and Black checklist.Results:Nineteen studies met the inclusion and exclusion criteria. Patients who underwent ACDF with a cage-only technique had significantly lower rates of postoperative dysphagia and adjacent segment disease compared with patients who underwent ACDF with a cage-plate technique. However, patients who underwent ACDF with a cage-plate technique had better radiographic outcomes with significantly less subsidence and better restoration of cervical lordosis. There were no other significant differences in outcomes or postoperative complications.Conclusions:ACDF with a cage-only technique appears to have better clinical outcomes than the cage-plate technique, despite radiographic findings of increased rates of subsidence and less restoration of cervical lordosis. Future randomized controlled trials with longer term follow-up are needed to confirm the findings of this meta-analysis.

Limestone particle size fed to pullets influences subsequent bone integrity of hens

This study was conducted to evaluate limestone particle size (LPS) in 2 strains of laying hens housed in conventional cages or aviaries on bone integrity. Lohmann Brown and Bovan White pullet chicks were started in equal numbers on the floor or in battery brooders and were intermingled throughout all subsequent housing systems. At 5 wk of age, 432 floor-raised pullets were moved to 8 aviary cages. At 10 wk, 256 battery-raised pullets were transferred to 64 conventional layer cages. Pullets were given diets containing fine (LPS-FINE, 0.431 mm) or a blend of fine and coarse (LPS-BLEND, 0.879 mm) LPS from 7 to 17 weeks. Data were analyzed as a split plot factorial design with strain as subplot and with 4 replicates for each treatment combination. Body weight, feed intake, egg production, and eggshell breaking strength and percentage were measured. Tibia bone mineral density (BMD) was determined using a dual energy x-ray absorptiometry. Presence of keel indentations, curvatures, or fractures was recorded. LPS-BLEND increased BMD (0.215 vs. 0.208, P = 0.03) at 18 weeks. During the pullet phase, the odds of pullets fed LPS-FINE displaying keel curvatures were 2.8 times the odds of those fed LPS-BLEND (P = 0.04). At 54 wk, hens fed LPS-BLEND as pullets had lower odds of keel indentations (P = 0.02). Brown aviary hens fed LPS-BLEND as pullets had the lowest egg production compared to the rest of the treatment combinations (P = 0.004). Taken together, feeding LPS-BLEND to pullets improved bone mineralization at the onset of sexual maturity and reduced keel damage during the pullet and layer phases, regardless of strain; however, LPS-BLEND was associated with lower egg production in Brown hens housed in aviaries compared to all others.

Mineral content of eggs differs with hen strain, age, and rearing environment

Egg nutrient quality is strongly influenced by hen diet but is also affected by rearing environment, hen strain, and hen age. The objective of the current study was to determine the effect of: 1) conventional battery cages, 2) enrichable cage systems, 3) enriched colony housing, 4) cage-free, and 5) free-range rearing systems on mineral concentrations of whole, dried egg (yolk and albumen combined) from TA Tetra White (TW) and Hy-Line Brown (HB) hens at 44, 68, and 88 wk of age. We hypothesized that mineral concentration of eggs would differ among rearing systems but not between strains or with hen age. Hens held in enriched colony housing systems produced eggs with 10% lower Mg and 11% lower Mn levels than conventional hens. Concentrations of Ca and Cu were higher (7 and 8%, respectively) in eggs from TW hens than from HB hens. Eggs from HB hens had 8% higher concentrations of Fe, 6% higher Mg and 5% higher Mn than TW hens. Mn was higher in eggs from 44-wk hens than from 68- or 88-wk hens (16 and 11%, respectively). Interaction effects between rearing environment and hen age were observed for K and Mn concentrations. Eggs from 68-wk hens in conventional rearing systems contained 14 to 21% more K than eggs from conventional hens at 44- and 88 wk and 14 to 18% more than eggs from 68-wk hens in other rearing systems. At 88 wk of age, hens in conventional rearing systems produced eggs with higher Mn concentration than hens in enrichable or enriched colony housing systems (22 and 23%, respectively). Interactions between rearing environment, hen strain, and hen age were observed for egg Zn levels among 44- and 68-wk hens but were not detectable among 88-wk hens regardless of rearing system or hen strain. Observed differences in egg mineral content in our study were small and are unlikely to have substantial impact on human nutrition.

Performance indexes’ evaluation of a NSynRM with sinusoidal rotor shape

This study presents the evaluation of performance indexes of a novel synchronous reluctance motor (NSynRM) that has an axially sinusoidal rotor lamination shape. The stator of a 5.5 kW, 4-pole, 50 Hz conventional three-phase squirrel cage induction motor, with distributed and chorded by one slot, double-layer winding, is used for both standard and NSynRMs. Owing to the nature of the sinusoidal rotor structure, the three-dimensional finite element analysis (FEA) is utilised to study the electromagnetic parameters of interests. The NSynRM with sinusoidal rotor shape results is compared with the standard SynRM without cut-off on the q -axis. The FEA results are validated by means of practical measurements.

Effect of simple and low-cost enrichment items on behavioral, clinical, and productive variables of caged laying hens

ABSTRACTHousing layers in battery cages is a practice still used by many countries but it has been criticized because of its influence on behavioral repertoire of birds. We investigated whether simple and affordable enrichment devices alone impact behavior, foot condition and performance of laying hens housed in conventional cages. Hens were divided into plain cages (CON), cages with perches (PER), and cages with tassels and scratch-pads (ENR), and parameters were evaluated before and after enrichment placement. After perch placement inactivity, drinking and competition for space reduced 35.6%, 40.8% and 70.3%, respectively, whereas social interaction increased 19.3%. Both modifications decreased locomotion (75.0% and 42.4% for PER and ENR respectively) and abnormal behaviors (62.5% and 43.9.4% for PER and ENR respectively). None of the performance variables were affected by ENR or PER. Thermography was more efficient than visual inspection in detecting subclinical bumblefoot, and it confirmed that PER reduced subclinical and clinical cases. Our findings indicate that perches increased welfare-related behaviors and foot health of hens, supporting the use of these inexpensive and highly adaptable alternatives for the enrichment of battery cages.

Radiostereometric analysis using clinical radiographic views: Development of a universal calibration object

Radiostereometric analysis (RSA) is a highly accurate technique used to provide three-dimensional (3D) measurements of orthopaedic implant migration for clinical research applications, yet its implementation in routine clinical examinations has been limited. Previous studies have introduced a modified RSA procedure that separates the calibration examinations from the patient examinations, allowing routine clinical radiographs to be analyzed using RSA. However, in order to calibrate the wide range of clinical views, a new calibration object is required. In this study, a universal, isotropic calibration object was designed to calibrate any pair of radiographic views used in the clinic for RSA. A numerical simulation technique was used to design the calibration object, followed by a phantom validation test of a prototype to verify the performance of the novel object, and to compare the measurement reliability to the conventional calibration cage. The 3D bias for the modified calibration method using the new calibration object was 0.032 ± 0.006 mm, the 3D repeatability standard deviation was 0.015 mm, and the 3D repeatability limit was 0.042 mm. Although statistical differences were present between the universal calibration object and the conventional cage, the differences were considered to be not clinically meaningful. The 3D bias and repeatability values obtained using the universal calibration object were well under the threshold acceptable for RSA, therefore it was successfully validated. The universal calibration object will help further the adoption of RSA into a more routine practice, providing the opportunity to generate quantitative databases on joint replacement performance.

Physicochemical determinants of pH in pectoralis major of three strains of laying hens housed in conventional and furnished cages

ABSTRACT1. Post-mortem decline in muscle pH has traditionally been attributed to glycogenolysis-induced lactate accumulation. However, muscle pH ([H+]) is controlled by complex physicochemical relationships encapsulated in the Stewart model of acid–base chemistry and is determined by three system-independent variables – strong ion difference ([SID]), total concentration of weak acids ([Atot]) and partial pressure of CO2 (PCO2).2. This study investigated these system-independent variables in post-mortem pectoralis major muscles of Shaver White, Lohmann Lite and Lohmann Brown laying hens housed in conventional cages (CC) or furnished cages (FC) and evaluated the model by comparing calculated [H+] with previously measured [H+] values.3. The model accounted for 99.7% of the variation in muscle [H+]. Differences in [SID] accounted for most or all of the variations in [H+] between strains. Greater PCO2 in FC was counteracted by greater sequestration of strong base cations. The results demonstrate the accuracy and utility of the Stewart model for investigating determinants of meat [H+].4. The housing differences identified in this study suggested that hens housed in FC have improved muscle function and overall health due to the increased opportunity for movement. These findings support past studies showing improved animal welfare for hens housed in FC compared to CC. Therefore, the Stewart model has been identified as an accurate method to assess changes in the muscle at a cellular level that affect meat quality that also detect differences in the welfare status of the research subjects.

Isolation and Characterization of Campylobacter hepaticus from Layer Chickens with Spotty Liver Disease in the United States.

Spotty liver disease (SLD) is characterized by multifocal liver lesions, mortality, and drop in egg production. The disease is emerging in Europe and Australia, particularly in free-range and floor-raised layer flocks. Campylobacter hepaticus has been recently identified as the causative agent of SLD. We report the isolation and characterization of C. hepaticus from livers of laying hens affected with SLD in the United States. Two isolates were characterized and found to be highly similar to those described from SLD cases in the United Kingdom and Australia. Initial isolation of C. hepaticus from liver samples required microaerophilic and thermophilic conditions and incubation for a particularly long duration (approximately 7 days). Morphologic and phenotypic properties of the isolates were typical for Campylobacter spp. Phylogenetic analysis based on 16S ribosomal RNA gene sequences and detection of a glycerol kinase gene confirmed the identity of the isolates as C. hepaticus. To the authors' knowledge, this is the first report of C. hepaticus isolation from layer chickens with SLD in the United States. With the increasing changes in the egg industry from conventional cages to cage-free housing systems, the incidence and economic impact of SLD could become significant.

Improving utilization of nests and decreasing mislaid eggs with narrow width of group nests

Provision of nest boxes is necessary for laying hens, especially in non-cage systems. This study investigated the effects of nest width on nest utilization and mislaid eggs. Hy-Line Browns hens were transferred from conventional cages to perchery pens at 12 weeks of age. Two experiments were conducted to mutually verify the hypothesis that narrowing group nests would improve nest utilization and reduce mislaid eggs. In experiment 1, group nests of 150 cm wide in two pens were partitioned at intervals of 50 cm and 37 cm, respectively. In experiment 2, partition panels were removed after acclimation. The number of mislaid eggs and nest eggs in each pre-set section were compared. Results indicated that narrowing group nests had positive effects on improving usage uniformity and efficiency of group nests. Nest eggs were more evenly distributed on the egg belt in both narrowed group nests, which was indicated by the significant decrease of variance among different sections. The proportion of mislaid eggs decreased by 3.5% in 37 cm treatment and 4.7% in 50 cm treatment, respectively. As expected, reuse of the 150 cm group nests after removal of partition panels lowered the usage uniformity of group nests. A growth of three percentage points was found for the proportion of mislaid eggs after removing the partition panels in 50 cm treatment. The present results indicated that it is the width of the nest box that works for a better use of group nests. In conclusion, adding partition panels at intervals of 50 cm and 37 cm in group nests both are effective on nest usage and decreasing the occurrence of mislaid eggs. Keywords: group nest, nest width, utilization, mislaid eggs, hen house, non-cage system, bird welfare DOI: 10.25165/j.ijabe.20181101.3167 Citation: Zheng H Y, Li B M, Chen G, Wang C Y. Improving utilization of nests and decreasing mislaid eggs with narrow width of group nests. Int J Agric & Biol Eng, 2018; 11(1): 83–87.

Improving energy efficiency in poultry farms through LED usage: a provincial study

Conventional cage layer barns typically exhibit distinct variations in light levels between tiers in cases where lamps are both ceiling mounted and where they are alternated between ceiling-mounted and drop-down fixtures. Light-emitting diodes (LED) offer benefits over traditional lamps including extended life, reduced energy consumption, no flicker and different lamp forms allowing a greater variety of applications; however, the impacts of such lighting systems have not been thoroughly investigated. A review of poultry layer farm energy consumption was conducted in the Canadian province of Nova Scotia and their barn lighting profiles analysed. From this, a 3-month trial was conducted to investigate the potential of replacing conventional lighting with in-cage modular LED lighting. This initial research suggests that there is potential for the application of LED modular lamps to be used within caged systems without negatively impacting bird welfare or performance, but with the benefit of improved energy efficiency.