Conventional Housing Systems Research Articles

Microbiological vulnerability of eggs and environmental conditions in conventional and free-range housing systems

Although Brazil is currently the world’s eighth largest egg exporter, the shift of consumers towards free-range eggs may present new sanitary challenges. This study aims to evaluate the microbiological vulnerability of eggs and environmental conditions in a farm certified for both conventional and free-range systems using two standard methods (enterobacteria counting and Salmonella spp. survey). Two high-producing farms were selected for this study, one under both conventional and free-range systems at the same place as the test farm, and another under conventional system only as a control farm. Enterobacteriaceae counts were determined for eggshells; and detection of Salmonella spp. was conducted in eggs, nest box material, feeder, and sponge samples from water dispensers, feeders, production plant, besides water samples from nipple dispensers and artesian well. The average enterobacteria count (log CFUmL-1) was 0.09 for conventional and 1.73 for free-range systems (p < 0.001). While Salmonella spp. was not detected in the conventional system but was present in one feeder and three eggshells from the free-range system. Therefore, the conventional system demonstrated better hygiene-sanitary status than the free-range one. Moreover, controlling food safety should always be considered when improving animal welfare.

Development of a Machine Vision Method for the Monitoring of Laying Hens and Detection of Multiple Nest Occupations.

Free range systems can improve the welfare of laying hens. However, the access to environmental resources can be partially limited by social interactions, feeding of hens, and productivity, can be not stable and damaging behaviors, or negative events, can be observed more frequently than in conventional housing systems. In order to reach a real improvement of the hens’ welfare the study of their laying performances and behaviors is necessary. With this purpose, many systems have been developed. However, most of them do not detect a multiple occupation of the nest negatively affecting the accuracy of data collected. To overcome this issue, a new “nest-usage-sensor” was developed and tested. It was based on the evaluation of thermografic images, as acquired by a thermo-camera, and the performing of patter recognitions on images acquired from the nest interior. The sensor was setup with a “Multiple Nest Occupation Threshold” of 796 colored pixels and a template of triangular shape and sizes of 43 × 33 pixels (high per base). It was tested through an experimental nesting system where 10 hens were reared for a month. Results showed that the evaluation of thermografic images could increase the detection performance of a multiple occupation of the nest and to apply an image pattern recognition technique could allow for counting the number of hens in the nest in case of a multiple occupation. As a consequence, the accuracy of data collected in studies on laying performances and behaviors of hens, reared in a free-range housing system, could result to be improved.

Manipulating the immune system for pigs to optimise performance

Disease and enhanced microbial load are considered to be major factors limiting the performance and overall efficiency of feed use by pigs in Australian piggeries. It is recognised that pigs exposed to conventional housing systems with high microbial loads grow 10–20% more slowly than do gnotobiotic pigs or pigs kept in ‘clean’ environments. Consequently, a proportion of pigs in any production cycle are continuously being challenged by their immediate environment, which can cause an immune response to be mounted. Such a process is physiologically expensive in terms of energy and protein (comprised of amino acids), with, for example, the enhanced rate of protein turnover associated with the production of immune cells, antibodies and acute-phase proteins increasing energy expenditure by 10–15% of maintenance needs and protein requirements by 7–10%. The requirements for lysine, tryptophan, sulfur-containing amino acids and threonine can be increased by a further 10%. The over-stimulation of the immune response with excess production of pro-inflammatory cytokines causes excessive production primarily of the prostaglandin E2 (PGE2), which contributes to anorexia, fever and increased proteolysis, and a concomitant reduction in pig performance. Prostaglandin E2 is produced from dietary and cell-membrane phospholipids via secretory phospholipase A2 (sPLA2) to produce arachidonic acid, which is catalysed by the COX-2 enzyme. Negating the negative effects of PGE2 appears not to adversely affect the ability of the immune system to combat pathogens, but improves pig performance. There are negative outcomes for pig health and productivity through both under- and over-stimulation of the immune response. This review briefly outlines the impact of immune stimulation on pigs and discusses strategies to optimise the immune response for pig health and performance.

Changes in the life cycle environmental footprint of egg production in Canada from 1962 to 2012

Current levels of productivity, resource efficiency and animal health on Canadian egg farms are superior to those achieved historically. Supply chain efficiencies have also changed over time. An important question, then, is to what extent have such changes influenced the sustainability of egg production?The current analysis provides a quantitative understanding of the actual scale and consequences of these changes in the Canadian egg industry. By evaluating to what extent and for what reasons the life cycle environmental footprint of conventional Canadian egg production – as measured in terms of acidifying, eutrophying, and greenhouse gas emissions, as well as energy, land, and water use – has changed over a 50 year interval spanning 1962 to 2012, the historical trajectory of the industry towards more sustainable practices is elucidated.Per unit of eggs produced in conventional cage housing systems in Canada in 2012 (which accounted for over 90% of production nationally), cradle-to-farm gate impacts were, on average, roughly one third of those estimated for egg production in Canada in 1962. Supply chain acidifying emissions declined by 61%, eutrophying emissions by 68%, and GHG emissions by 72%, while life cycle energy, land and water use decreased by 41%, 81% and 69% respectively. Moreover, despite that egg production volumes increased from 43.4 million dozen to 65.7 million dozen eggs per year between 1962 and 2012 – an increase of over 50% - the industry's overall environmental footprint actually decreased across all emissions and resource use domains considered. Industry total life cycle emissions for egg production were 41%, 51% and 57% lower for acidifying, eutrophying, and greenhouse gas emissions respectively. Energy, land and water use were 10%, 71% and 53% lower.These observed changes are attributable to a combination of factors, including: improved efficiencies in the supply chain activities that support egg production; changes in the composition of feeds sourced for both pullet and egg production; and significant improvements in resource efficiencies, animal health, and productivity at the level of pullet and egg production.

Productivity and Financial Viability of Commercial Broiler Farm Using Climate Controlled System: The Case in a State-Owned University in Nueva Ecija, Philippine

This study analyzed the performance and profitability of broiler production in a climate controlled system (CCS) operated by a state-owned academic institution under a contract growing scheme. Production efficiency such as average live weight (ALW), feed conversion ratio (FCR), and livability or harvest recovery (HR) of broilers under CCS in 11 growing cycles were analyzed and compared with broilers in conventional housing. The financial viability of the CCS was examined using cost and return analysis. All the data were subjected to t-test with uneven number of observation using the General Linear Model of Statistica for Windows Version 8, 2007. Moreover, regression analysis was done to further determine the effects of type of housing on productivity and profitability. Broilers under conventional and CCS housing system have similar ALW (P>0.05) of 1.63 kg and 1.65 kg, respectively, at 35 days. Both of these values are higher than the standard set by the integrator. However, FCR and HR of the broilers under CCS were significantly better (P<0.05). They have more growth uniformity and cumulative livability than those in conventional housing. With better FCR and HR, there is higher revenue per bird in CCS than in conventional housing, PHP 14.69 vs PHP 11.96. Moreover, return over total expenses was significantly higher at 150% for CCS and 84% in conventional housing. The higher productivity of broilers under CCS compensated for the higher cost of investment.

A method of determining bending properties of poultry long bones using beam analysis and micro-CT data

While conventional mechanical testing has been regarded as a gold standard for the evaluation of bone heath in numerous studies, with recent advances in medical imaging, virtual methods of biomechanics are rapidly evolving in the human literature. The objective of the current study was to evaluate the feasibility of determining the elastic and failure properties of poultry long bones using established methods of analysis from the human literature. In order to incorporate a large range of bone sizes and densities, a small number of specimens were utilized from an ongoing study of Regmi et al. (2016) that involved humeri and tibiae from 3 groups of animals (10 from each) including aviary, enriched, and conventional housing systems. Half the animals from each group were used for ‘training’ that involved the development of a regression equation relating bone density and geometry to bending properties from conventional mechanical tests. The remaining specimens from each group were used for ‘testing’ in which the mechanical properties from conventional tests were compared to those predicted by the regression equations. Based on the regression equations, the coefficients of determination for the ‘test’ set of data were 0.798 for bending bone stiffness and 0.901 for the yield (or failure) moment of the bones. All regression slopes and intercepts values for the tests versus predicted plots were not significantly different from 1 and 0, respectively. The study showed the feasibility of developing future methods of virtual biomechanics for the evaluation of poultry long bones. With further development, virtual biomechanics may have utility in future in vivo studies to assess laying hen bone health over time without the need to sacrifice large groups of animals at each time point.

Effect of deep litter housing and fermented feed on carcass characteristics and meat quality of crossbred Hampshire pigs.

Aim:The objective of the study was to evaluate the effect of deep litter housing and fermented feed on carcass characteristics and meat quality of crossbred Hampshire pigs.Materials and Methods:Forty-eight weaned crossbred Hampshire piglets of 2 months age (24 males and 24 females) were selected for the experiment. The piglets were randomly assigned into 4 homogenous experimental groups with 6 males and 6 females each: E1; reared on a conventional housing and fed with a fermented diet, E2; reared on a deep litter housing system and fed with a fermented diet, E3; reared on a deep litter housing system and fed with a conventional diet and C; reared on a conventional housing system and fed with a conventional diet. The study was continued up to 32 weeks of age and at the end of this period, 6 animals (3 males and 3 females) from each experimental group were slaughtered to evaluate carcass traits and meat quality characteristics.Results:Pre-slaughter weight, hot carcass weight, and dressing percentage were significantly (p<0.01) affected by feeding fermented diet and deep litter housing while carcass traits, i.e., carcass length, backfat thickness, and loin eye area were not affected. The edible offal; liver and heart weight (p<0.05) differed significantly while kidney weight showed no difference. The inedible offal; head weight (p<0.01) and lung weight revealed a significant difference (p<0.05) while spleen and stomach weight showed no difference among the experimental groups. The wholesale cuts and meat: bone ratio of pigs also differed significantly among the groups. Morphometry of small and large intestine also showed a significant difference. Chemical composition of pork viz., moisture and total ash content was influenced by the treatment, while crude protein and ether extract content were not affected. Mineral composition of pork also showed no significant difference. Color characteristics of Longissimus dorsi muscle showed a significant difference in L* and a* value while parameter b* was not affected. The tenderness of meat showed significant difference among the groups (p<0.01).Conclusion:Crossbred Hampshire pigs being reared on fermented feed and deep litter housing could produce highlygraded carcass and improvement in meat quality.

Environmental assessment of three egg production systems — Part II. Ammonia, greenhouse gas, and particulate matter emissions

As an integral part of the Coalition for Sustainable Egg Supply (CSES) Project, this study simultaneously monitored air emissions of 3 commercially operated egg production systems at the house level and associated manure storage over 2 single-cycle flocks (18 to 78 wk of age). The 3 housing systems were 1) a conventional cage house (CC) with a 200,000-hen capacity (6 hens in a cage at a stocking density of 516 cm2/hen), 2) an enriched colony house (EC) with a 50,000-hen capacity (60 hens per colony at a stocking density of 752 cm2/hen), and 3) an aviary house (AV) with a 50,000-hen capacity (at a stocking density of 1253 to 1257 cm2/hen). The 3 hen houses were located on the same farm and were populated with Lohmann white hens of the same age. Indoor environment and house-level gaseous (ammonia [NH3] and greenhouse gasses [GHG], including carbon dioxide [CO2], methane [CH4], and nitrous oxide [N2 O]) and particulate matter (PM10, PM2.5) emissions were monitored continually. Gaseous emissions from the respective manure storage of each housing system were also monitored. Emission rates (ERs) are expressed as emission quantities per hen, per animal unit (AU, 500 kg live BW), and per kilogram of egg output. House-level NH3 ER (g/hen/d) of EC (0.054) was significantly lower than that of CC (0.082) or AV (0.112) (P < 0.05). The house-level CO2 ER (g/hen/d) was lower for CC (68.3) than for EC and AV (74.4 and 74.0, respectively), and the CH4 ER (g/hen/d) was similar for all 3 houses (0.07 to 0.08). The house-level PM ER (mg/hen/d), essentially representing the farm-level PM ER, was significantly higher for AV (PM10 100.3 and PM2.5 8.8) than for CC (PM10 15.7 and PM2.5 0.9) or EC (PM10 15.6 and PM2.5 1.7) (P < 0.05). The farm-level (house plus manure storage) NH3 ER (g/hen/d) was significantly lower for EC (0.16) than for CC (0.29) or AV (0.30) (P < 0.05). As expected, the magnitudes of GHG emissions were rather small for all 3 production systems. Data from this study enable comparative assessment of conventional vs. alternative hen housing systems regarding air emissions and enhance the U.S. national air emissions inventory for farm animal operations.

Microbiological contamination of shell eggs produced in conventional and free-range housing systems

The present study was conducted to determine microbiological contamination of free-range and conventional chicken eggs produced under controlled conditions. Eighty-four certified Salmonella-free Bovan Brown chicks (age 2 days) were grown in 6 separate floor pens until age 16 weeks, and then moved into 3 conventional battery cages (BC) or 3 free-range (FR) housing systems. Total aerobic microorganisms and Enterobacteriaceae on egg shell surfaces were enumerated weekly when the hens were 20–27 weeks of age (N = 535 and N = 541 for BC and FR, respectively). Prevalence of Salmonella and Campylobacter were determined on crushed egg shells (N = 212 and N = 176, respectively) and in feces (N = 36 and N = 30, respectively) collected from hens at 24 and 28 weeks of age. Counts of total aerobic microorganisms recovered from BC and FR eggs ranged from 5.0 to 6.0 log10 CFU/mL. Numbers of Enterobacteriaceae averaged 1.0 log CFU/mL higher (90% greater) on FR eggs than on eggs from BC hens. Salmonella was not detected on any of the eggs collected from BC hens (0/212), but prevalence on eggs collected from FR hens was 2.36% positive (5/212). Prevalence of Campylobacter recovered from eggs collected from FR (26.1% positive or 46 out of 176 positive) was significantly higher (P ≤ 0.0001) than the prevalence of Campylobacter recovered from eggs from BC hens (7.4% positive or 13 out of 176 positive). These data demonstrate that FR eggs, where hens have more contact with eggs after oviposition, have greater microbiological contamination on the egg shell surface than eggs produced in the BC cage systems.

Tail biting behaviour and tail damage in pigs and the relationship with general behaviour: Predicting the inevitable?

Tail biting behaviour in pigs is a common problem in conventional housing systems. Our study examined the consistency over time in tail biting and tail damage and it explored the predictive value of general behaviours observed in individual pigs and in pens as a whole.Pigs (n=480), reared in conventional farrowing pens with a sow crate, were followed from pre-weaning to slaughter (23 weeks). Post-weaning, piglets were housed barren (B) or enriched (E). Behaviours were observed pre-weaning (averaged per litter) and post-weaning in three phases (weaner, grower, finisher) (averaged per pig/phase). Tail damage of individual pigs was scored weekly from weaning (4 weeks) onwards (averaged per phase). Relationships between tail biting and tail damage with behaviour were investigated both at individual and pen level using mixed or generalized linear mixed models and Spearman's rank correlations, respectively.Tail biting and tail damage (2.1±0.05, 1=no tail damage, 4=tail wound) were already observed pre-weaning. Post-weaning, tail biting and tail damage were less prevalent in E compared to B housing (P<0.001). Tail biting behaviour in individual pigs was not consistently observed over time, i.e. none of the pigs was tail biter in all three phases, so new tail biters were found in later phases and some of the already identified tail biters stopped tail biting completely or temporarily. In B housing 38.3% and in E housing 5.6% of pigs was identified as tail biter in at least one phase post-weaning. B housed tail biters in different phases were likely to originate from litters with a relatively high level of tail biting behaviour pre-weaning (P<0.05–0.01). Generally, post-weaning victims were likely to be a victim again in successive phases of life (B: P<0.10–0.001; E: P<0.01). Tail biting and tail damage were best predicted by behaviours at pen level and less by behaviours at the individual level: a higher activity, and more pig and pen-directed manipulative behaviours were observed in pens with high levels of tail biting. Particularly higher levels of chewing or consuming objects such as jute sacks could be useful in predicting tail bite outbreaks. To conclude, tail biting in pigs starts early in life and is difficult to predict due to its inconsistency, although tail damage is more consistent throughout life. Especially behaviour observed at litter or pen level is a promising tool in predicting tail biting and tail damage.

The effect of different pen cleaning techniques and housing systems on indoor concentrations of particulate matter, ammonia and greenhouse gases (CO2, CH4, N2O)

The objective of this study was to investigate the effect of two pen cleaning techniques for pig fattening houses on the indoor concentrations of particulate matter (PM1, PM2.5 and PM10), ammonia (NH3) and greenhouse gases (CO2, CH4, N2O), using a multi-pollutant approach. Both cleaning techniques were tested in a conventional housing system and in a low-ammonia-emission housing system. In total, four compartments from the conventional housing system and four from the low-ammonia-emission housing system were sampled during two consecutive fattening periods between August 2011 and June 2012. Two compartments from each housing system were only cleaned dry, while the other two received a more intensive cleaning. Indoor concentrations of NH3, CO2, CH4, N2O and PM were measured continuously.Overall, the low-ammonia-emission housing system showed no reduction in indoor pollutant concentrations compared to the conventional system, except for CH4. The additional wet cleaning and disinfection step in the more intensive cleaning protocol did not result in consistently lower indoor concentrations for the studied pollutants.

Modelling ventilation rate, balance temperature and supplemental heat need in alternative vs. conventional laying-hen housing systems

An Excel-based spreadsheet model has been developed to delineate ventilation rate (VR), supplemental heat need ( H s ), balance temperature ( t bal , outdoor temperature below which H s is required to maintain the desired indoor temperature), energy use and cost for H s in alternative (aviary and enriched colony) vs. conventional cage laying-hen houses. The model was applied to the Midwestern U.S. housing characteristics (same land footprint) and winter weather conditions (−30 °C to 5 °C ambient temperature, and a constant relative humidity or RH of 70%). Effects of hen stocking density, target indoor temperature and RH ( t i , RH i ), building insulation, and light period vs. dark period on VR, t bal and H s were examined. For the housing characteristics considered and target indoor condition of 25 °C and 60% RH, t bal for the alternative housing systems was found to be 2.0–2.6 °C higher than that for the conventional cage counterpart. The supplemental heater capacity would need to be 20.5–22.0 kW per 10,000 hens for the aviary houses (107,000-hen capacity) and 17.6 kW per 10,000 hens for the enriched colony house (124,000-hen capacity). Annual H s was estimated to be 0.09 and 0.12 MJ [kg egg] −1 for the enriched and aviary houses, respectively. The corresponding H s cost (in US dollars) would be, respectively, 0.11 and 0.15 US cent [kg egg] −1 at a wholesale liquid propane (LP) fuel price of $0.32 l −1 ($1.21 gal −1 ) or 0.26 and 0.35 US cent [kg egg] −1 at a retail LP fuel price of $0.75 l −1 ($2.84 gal −1 ). Among all the influencing factors considered, t i and RH i setpoints had more pronounced impacts on t bal and H s . The analysis indicated that H s energy cost for the alternative housing systems in the Midwestern USA is less than 0.3% of the total production cost. The simulation model was validated with measured heating energy use by a commercial aviary house in northern Iowa and the difference between the predicted and field-measured H s values was less than 5%. This interactive model can be readily used for analysis of other laying-hen housing, climatic conditions, and/or management scenarios.

Dynamics of air temperature, velocity and ammonia emissions in enclosed and conventional pig housing systems.

This study aimed to compare the dynamics of air temperature and velocity under two different ventilation and housing systems during summer and winter in Korea. The NH3 concentration of both housing systems was also investigated in relation to the pig’s growth. The ventilation systems used were; negative pressure type for the enclosed pig house (EPH) and natural airflow for the conventional pig house (CPH). Against a highly fluctuating outdoor temperature, the EPH was able to maintain a stable temperature at 24.8 to 29.1°C during summer and 17.9 to 23.1°C during winter whilst the CPH had a wider temperature variance during summer at 24.7 to 32.3°C. However, the temperature fluctuation of the CPH during winter was almost the same with that of EPH at 14.5 to 18.2°C. The NH3 levels in the CPH ranged from 9.31 to 16.9 mg/L during summer and 5.1 to 19.7 mg/L during winter whilst that of the EPH pig house was 7.9 to 16.1 mg/L and 3.7 to 9.6 mg/L during summer and winter, respectively. These values were less than the critical ammonia level for pigs with the EPH maintaining a lower level than the CPH in both winter and summer. The air velocity at pig nose level in the EPH during summer was 0.23 m/s, enough to provide comfort because of the unique design of the inlet feature. However, no air movement was observed in almost all the lower portions of the CPH during winter because of the absence of an inlet feature. There was a significant improvement in weight gain and feed intake of pigs reared in the EPH compared to the CPH (p<0.05). These findings proved that despite the difference in the housing systems, a stable indoor temperature was necessary to minimize the impact of an avoidable and highly fluctuating outdoor temperature. The EPH consistently maintained an effective indoor airspeed irrespective of season; however the CPH had defective and stagnant air at pig nose level during winter. Characteristics of airflow direction and pattern were consistent relative to housing system during both summer and winter but not of airspeed. The ideal air velocity measurement favored the EPH and therefore can be appropriate for the Korean environment. Further emphasis on its cost effectiveness will be the subject of future investigations.

Influence of housing on endocrine function and immune system in pregnant sows

Regrouping of unfamiliar animals as well as individual housing can lead to social stress causing an activation of physiological stress systems that affect various immune functions. Whereas EU guidelines (2001/88/EG) impose the housing of pregnant sows in social groups by 2013, individual housing is still the most conventional housing system in numerous countries. However, the effects of different housing systems on immune functions in pregnant sows are poorly investigated. Therefore, this study aimed at characterizing endocrine and immunological responses during the second half of gestation in sows kept in different housing systems. Blood samples of pregnant sows (German Landrace) either housed in single crates ( n = 11) or in a dynamic group ( n = 22) were taken 7, 6, 4, and 2 weeks pre partum and the number of different leucocyte subpopulations, the proliferative response of lymphocytes to stimulation with concanavalin A or pokeweed mitogen as well as plasma cortisol concentrations were evaluated. Significantly higher absolute numbers of helper T cells (CD3 + CD4 + CD8 +/− ) as well as cytotoxic T cells (CD3 + CD4 − CD8 + ) were found in group housed sows at most sampling points. Proliferative lymphocyte responses to each mitogen did not differ between sows of the two housing systems. However, sows kept in single crates showed a tendency for higher cortisol concentrations 7 weeks pre partum and significantly higher cortisol concentrations two weeks before parturition. In summary, these results indicate substantial effects on the neuroendocrine-immune system of pregnant sows depending on the housing system, which might affect their ability to deal with infection.

The welfare of laying hens in conventional cages and alternative systems: first steps towards a quantitative comparison

AbstractResearch synthesis, using techniques such as meta-analysis to combine the results of a number of studies, is a particularly useful technique when there are multiple studies with conflicting results, or where there may be conflicting interests, and can serve to extract the maximum information from animal experiments. The effect of conventional cages and alternative housing systems on measures of production, behaviour, physical and physiological condition in laying hens is an important question that would benefit from research synthesis. We found that statistical constraints did not allow the usual methods of meta-analysis, so as a first step towards quantitative comparison, we used a simple vote-counting approach based on the treatment means. We counted the number of papers in which conventional cages or alternative systems had a higher weighted mean for various response variables. Egg production was higher in conventional cages than in alternative systems, though this effect was probably mostly confined to the comparison with multi-level indoor systems. Bones were stronger from hens kept in alternative systems than those kept in conventional cages. We confirmed previous reviews that birds show more comfort behaviour and possibly dustbathing (or vacuum dustbathing) behaviour in alternative systems, but aggressive pecking did not differ between systems. Perhaps surprisingly, mortality, feather pecking and body wounds were not found to differ between systems. The latter findings suggest that the chance of a mortality or cannibalism outbreak may be no greater in alternative systems than in cage systems, but it should be noted that our analysis did not consider the magnitude of the difference in mortality. In conclusion, the meta-comparison undertaken here supports some but contradicts other conclusions reached in qualitative reviews.

A study on bioaccumulation of selected metals in meat and internal organs of intenstively fed kid goats

Owing to its wholesomeness and good taste, meat of goats and lambs is an increasingly more important in human nutrition. It is characterized by excellent nutritive value and high digestibility. It is also relatively rich in mineral compounds. The aim of this study has been to determine the content of some elements in muscles, liver and kidneys of male and felame kid goats, fattened to 150 day of life. The animals received full-ration mixture containing 169 g total protein and 6.0 MJ net energy. The mixture was given ad libitum and supplemented with meadow hay as bulk feed. During the whole period of fattening, the animals were kept under the conventional housing system. Samples for analysis were taken from adductor femoris muscles, liver and kidneys. The muscle tissue of the analysed male goats contained less Cd (0.002 mg kg-1 ± 0.004) than that of the female goats (0.003 mg kg-1 ± 0.001). In turn, the level Pb was lower in the female goats (0.019 mg kg-1 versus 0.026 mg kg-1 in male goats), although the difference was statistically non-significant. In the internal organs, more Cd occurred in kidneys than in the liver, unlike Pb. The concentration Pb was higher in kidneys of the male than female goats (0.073 mg kg-1 ± 0.02), whereas the level of this element the liver was identical in both groups (0.084 mg kg-1 ). In the muscule tissue, the sex differentiated the content of Fe (p = 0.01) as well as Mg and Zn (p = 0.05). The liver accumulated not only Pb and Cd, but also Cu and Zn. The concentration Cu in the liver of female goats was higher (146.79 mg kg-1 at p = 0.01) than in male goats by about 50 mg kg-1. High disproportions between the sexes in the content of Fe in the liver were observed: 36.30 mg kg-1 for female goats and 21.99 mg kg-1 for male goats (p = 0,01). In kidneys, however, the concentration of Ca was very high, particularly for female goats particularly (81.01 ± 26.55 mg kg-1). 502

Effect of an organic and conventional rearing system on the mineral content of hen eggs

In this study, the effect on mineral content of eggs from organic and conventional-housing systems was investigated. For this, random samples of 12 eggs were collected in both housing systems. Egg shells and edible portions were analysed for ash, Ca, P, Mg, Fe, Zn and Cu contents.The P and Zn contents of the edible egg portion were lower in the organic eggs than in conventional eggs. Mg content of the eggshell was higher in organic eggs while Zn content showed a marked decrease. As far as Ca, Fe and Cu values were concerned, these did not differ between the eggs from organic and conventional systems.The results showed considerable differences in mineral content between the eggs from the hens reared in organic and conventional systems.

Simple, Economical Heat-Shock Devices for Zebrafish Housing Racks

One reason for the popularity of the zebrafish (Danio rerio) as a model vertebrate is the ability to manipulate gene expression in this organism. A common method is to induce gene expression transiently under control of a heat-shock promoter (e.g., hsp70l). By making simple mechanical adjustments to small aquarium heaters (25-50W), we were able to produce consistent and reliable heat-shock conditions within a conventional zebrafish housing system. Up to two heat-shock intervals per day (>37°C) could be maintained under conditions of continuous flow (5-25 mL/min). Temperature logging every 30 s indicated rapid warm up times, consistent heat-shock lengths, and accurate and precise peak water temperatures (mean±SD=38°C±0.2°C). The biological effects of these heat-shock treatments were confirmed by observing inducible expression of enhanced green fluorescent protein (EGFP) and inhibition of caudal fin regeneration in a transgenic fish line expressing a dominant negative fibroblast growth factor receptor (Tg(hsp70l:dnfgfr1-EGFP)(pd1)). These devices are inexpensive, easily modified, and can be calibrated to accommodate a variety of experimental designs. After setup on a programmable timer, the heaters require no intervention to produce consistent daily heat shocks, and all other standard care protocols can be followed in the fish facility. The simplicity and stability of these devices make them suitable for long-term heat shocks at any stage of the zebrafish lifecycle (>7 days postfertilization), and useful for both laboratory and classroom experiments on transgenic zebrafish.

Effect of environmental enrichment on productive performance and welfare aspects in fattening rabbits

Fattening rabbits are conventionally housed in 2 animals per cages, according to the local tradition. Presently in Europe no EU Directive exists on cage dimensions for these animals, while in some Countries local Codes (i.e.Ministry of Agriculture, U.K., 1987) indicate the housing dimensions for fattening rabbits (rabbits between 5 and 12 weeks of age: 0.07m2 pro capite; rabbits above 12 weeks of age: 0.18m2 pro capite in individual cages and rabbit between 5 and 12 weeks of age: 0.09m2 in colony cages). The conventional housing system may negatively affect animals' welfare, both for breeding and for fattening rabbits (Verga, 2000). No abnormal behaviours have been shown in group-housed females (Gunn, 1994) while they have been found in males, because they may become more aggressive when reaching sexual maturity (Hackness and Wagner, 1989)...

Environmental impacts and sustainability of egg production systems

As part of a systemic assessment toward social sustainability of egg production, we have reviewed current knowledge about the environmental impacts of egg production systems and identified topics requiring further research. Currently, we know that 1) high-rise cage houses generally have poorer air quality and emit more ammonia than manure belt (MB) cage houses; 2) manure removal frequency in MB houses greatly affects ammonia emissions; 3) emissions from manure storage are largely affected by storage conditions, including ventilation rate, manure moisture content, air temperature, and stacking profile; 4) more baseline data on air emissions from high-rise and MB houses are being collected in the United States to complement earlier measurements; 5) noncage houses generally have poorer air quality (ammonia and dust levels) than cage houses; 6) noncage houses tend to be colder during cold weather due to a lower stocking density than caged houses, leading to greater feed and fuel energy use; 7) hens in noncage houses are less efficient in resource (feed, energy, and land) utilization, leading to a greater carbon footprint; 8) excessive application of hen manure to cropland can lead to nutrient runoff to water bodies; 9) hen manure on open (free) range may be subject to runoff during rainfall, although quantitative data are lacking; 10) mitigation technologies exist to reduce generation and emission of noxious gases and dust; however, work is needed to evaluate their economic feasibility and optimize design; and 11) dietary modification shows promise for mitigating emissions. Further research is needed on 1) indoor air quality, barn emissions, thermal conditions, and energy use in alternative hen housing systems (1-story floor, aviary, and enriched cage systems), along with conventional housing systems under different production conditions; 2) environmental footprint for different US egg production systems through life cycle assessment; 3) practical means to mitigate air emissions from different production systems; 4) process-based models for predicting air emissions and their fate; and 5) the interactions between air quality, housing system, worker health, and animal health and welfare.