At the time of writing I’m just back from the annual board meeting and publishers discussions about the journal. The board meeting was excellent – with the new board members fitting in easily – but of course many of us have known them for a long time. The WPSA board is rather like a family in that people look out for each other. As some of you know, I had a bad accident in December last year and have been rather incapacitated with a broken femur neck, and the WPSA board members have been very supportive during this time. I would like to express my appreciation to all of them at this time.

In terms of business, the board is very sharp and keeps a tight rein on how the association is run. In these terms, we are all very conscious of what the association can provide for members, including the journal. Interestingly, the change in March in terms of making the journal online only unless a print copy was specifically requested, has yielded some quirky findings – including members now asking where their print copy has gone. This is despite publicity on the wrapper and within the journal regarding the change, and the purpose of this change (i.e. to reduce costs for printing and freight), which frees up valuable resources for other functions, such as funds for supporting speakers and conference attendance for students and those from lower income countries. It does beg the question how often the print copy is actually read, or whether it is just put on a book shelf. So for all members out there that still want a print copy, please think first about this decision. We are happy to provide a hard copy, but it comes at a relatively high price that can deprive other members of a valuable resource for other needs. If you don’t need a hard copy, please keep to online only and allow us extra funding for other projects.

For this current issue, we have a variety of topics being covered, including welfare, disease, immunity, specialist cereals for poultry diets and economics. Please keep the diversity of topics in papers coming in – we really appreciate providing something for everyone at WPSJ. On that topic, we could do with more papers on poultry processing if possible, so for all those readers out there who work in this field, please think of the journal when writing your papers. As always, my focus is to provide a quality review journal encompassing all aspects of poultry production – and submission is easy via the online system at manuscript central.

So I trust you find useful information in this issue and keep the papers coming in! We already have enough for March 2014 and beyond, which is very encouraging.

Dr Lucy Waldron

Editor

The use of carbohydrases and proteases in poultry production occasionally results in inconsistent physiological responses that are difficult to explain. However, it has previously been demonstrated that a substantial portion of the variation in enzyme efficacy is associated with the inherent ileal digestibility of starch, protein and lipid, and so an appreciation for the concentration of the undigested fractions of these nutrients in a diet may help to determine the magnitude and consistency of feed enzyme responses. Considering that the expense of in vivo physiological assays for the assessment of enzyme functional pattern is high, it is crucial to develop suitable in vitro methods to predict the magnitude of enzyme response. The purpose of the current paper is to describe inherent characteristics of poultry diets and feed ingredients in response to carbohydrases and proteases in order to aid the development of in vitro assays to predict feed enzyme functional patterns.

Studies on the prevalence of feather pecking in different commercial laying hen systems and its welfare and economic impacts are reviewed in the following paper. Current methods for controlling feather pecking include beak-trimming and alterations to light regimes, but these methods have significant disadvantages from the perspective of bird welfare. A substantial body of research has now identified risk factors for feather pecking during both the rearing and laying periods. It is argued that these findings can be translated into optimised management practices that can prevent and control feather pecking whilst simultaneously conferring welfare benefits. The genetic basis of feather pecking is considered, and studies that suggest group selection techniques could produce birds with a reduced tendency to feather peck in commercial flocks are highlighted.

Electrolytes (sodium, potassium and chloride) are compounds that dissolve into positive and negative particles in solution. The relationship between these compounds, known as the ‘dietary electrolyte balance’ (DEB), is affected by either electrolyte or its supplemental salt source. The National Research Council recommended 0.20% sodium, chloride, and 0.30% potassium for starter phase and lower doses of sodium and chloride for the finisher phase of broilers. However, these requirements are increased under heat stress conditions, and birds perform better when increasing levels of these electrolytes are offered, maintaining a DEB of preferably 250 mEq/kg. Increased levels of these electrolytes, especially sodium, were found effective for growth but caused increased water consumption and ultimately higher litter moisture in summer. Potassium and chloride were found effective in the diets of heat-stressed broilers. Sodium bicarbonate and potassium chloride have been recognised as the best choice in salt selection for broiler diets, particularly under hot summer conditions. In conclusion, a combination of the electrolytes with higher levels of cations and lower level of anions is recommended. Furthermore, the requirements of these electrolytes should be explored, with reference to current poultry housing systems and modern genetics.

Severe disease outbreaks of erysipelas in poultry flocks are caused by infection with the bacterium Erysipelothrix rhusiopathiae. This disease occurs in a wide range of poultry, including turkey, broiler chicken, hen, goose, and pheasant flocks. Erysipelas usually follows an acute course in birds, in the form of sepsis. Infections with E. rhusiopathiae occur through damaged skin or mucous membranes. The symptoms that occur just before death include unsteady locomotion and a lack of coordinated movement. A chronic form of bacterial infection primarily occurs in turkeys that have been vaccinated against erysipelas, and, in addition to affecting the joints, endocarditis can occur. Usually, carcasses are in good condition and correctly muscled, although ecchymosis might be visible in subcutaneous fat and thigh muscles, while internal organs become enlarged, such as the liver, spleen and kidneys. Histopathological tests indicate major vascular changes in the parenchymatous organs. Points of necrosis related to the infarctions of the large vessels are rarely observed, whereas spilled degenerative changes of parenchymatous organs are more likely to be observed. Turkeys are the only species of poultry for which vaccines against erysipelas have been registered; however, this vaccination is also effective for other poultry. E. rhusiopathiae is mainly sensitive to penicillin, but also responds to cephalosporins, tetracyclines, quinolines, clindamycin, erythromycin, and piperacillin.

High ambient temperatures in tropical and subtropical regions adversely affect the growth and egg productive performance of both broiler and laying chickens. Relative humidity and ventilation rate influences bird's performance, particularly when they are reared in open sided poultry houses. Genetic approaches that aid in reducing or altering the extent of plumage cover has, as a result, been adopted in many hot regions. Fortunately, there are some major and marker genes can reduce the deleterious effects of heat stress, naked neck (Na) and frizzle (F) genes being the most notable ones. The bulk of relevant literature has shown that their favourable effects on growth and laying performance are well established. Therefore, the naked neck and frizzle genes can be a viable alternative for broiler and layer production particularly, in the tropical countries where summer temperatures are very high.

The requirements of different electrolytes (sodium, potassium and chloride), dietary electrolyte balance (DEB) and salt source in broilers have considerably changed in recent times. The increasing level of sodium (Na), potassium (K) and DEB are associated with higher pH (i.e. alkalosis) while lower levels of chloride (Cl) and DEB are linked with a lower pH (i.e. acidosis). A narrow range of DEB (150-250 mEq/kg) is recommended to overcome the variations in acid base homeostasis and normal blood chemistry especially in summer conditions. The supplementation of suitable salts like NaHCO3 and KCl are proven to be beneficial to sustain viability of various biochemical processes. The cations usually alleviate whereas anions exacerbate the lysine:arginine antagonism. In most cases, the electrolytes and their balance (DEB) are considered ineffective in order to influence carcass and related traits; however, the supplementation of their respective salts, particularly NaHCO3 and KCl under heat stress, showed contrary but potentially useful results. The role of electrolytes in combination with coccidiostats is still ambiguous; however, the level of both entities (electrolytes and coccidiostats) should be kept low and studied in detail for mutual compatibility. The inclusion level of electrolytes from various salt sources changes whenever there is change in coccidiostat and environmental condition. Keeping in mind environmental constraints, it is recommended to use the lowest dosage of NaHCO3/ NaCl alongside ionophores. Consequently, it is recommended to supplement electrolytes through a combination of NaHCO3 and KCl, and maintaining dietary electrolyte balance (150-250 mEq/kg) is mandatory to exploit improved physiological responses of broilers for maximum growth response.

Poultry enteric diseases are an important economic problem involving many etiologic agents, including enteric viruses. Several viral agents have been detected around the world in enteric contents isolated from commercial chicken and turkeys flocks that initially appear healthy but exhibit enteric signs, such as diarrhoea, decreased food consumption, loss of body weight, and mortality. Chicken astrovirus, avian nephritis virus, chicken parvovirus, infectious bronchitis virus, fowl adenovirus group 1, avian reovirus, and avian rotavirus have been identified in chickens with enteric diseases. However, no single virus has been established as directly causative of enteric diseases. Knowledge of these viruses is minimal, and information regarding their role in enteric diseases is also scarce. This lack of knowledge, together with the important economic impact that enteric diseases have on poultry, justify the importance of their study. In the present review, all viruses involved in enteric diseases are discussed, with greater emphasis placed on those of the most prevalent.

Injurious pecking is a serious concern for commercial turkey production and welfare. The behaviour is thought to represent re-directed ground foraging, but the development and causes are poorly understood with little supporting literature. In the initial development of the behaviour, early lighting regimes and social facilitation may play contributing roles. Other factors such as the availability of foraging material, diet composition, stocking densities, and group dynamics may also affect levels of injurious pecking. Given that commercial turkeys are group-housed, alternative breeding techniques, like group selection based on social effects, might successfully reduce moralities from pecking without detracting selection pressure from economic traits. However, to better suit their behavioural needs, any genetic attempts to adapt turkeys to perform less injurious pecking should be done in combination with environmental and dietary improvements.

Maize is the preferred energy cereal used in poultry feed formulations because of its high energy, low fibre and the presence of pigments and essential fatty acids. Consequently because it is a primary source of energy, due to its higher level of inclusion in poultry diets (60-70%), it contributes approximately 30% of the protein requirement of poultry. However, maize, like other cereals, is deficient in certain essential amino acids, such as lysine and tryptophan. Therefore, to meet the requirements of these essential amino acids, farmers and feed producers usually supplement poultry rations with synthetic amino acids. Quality protein maize (QPM), with almost double the lysine and tryptophan levels, is no different from that of normal maize (NM) in terms of the quantity of energy and protein it contains. Consequently, inclusion of QPM in poultry formulations will enable the feed manufacturer to produce feeds requiring minimal or no additional supplementation of crystalline amino acids particularly lysine and tryptophan. This review examines the available research on the nutritional value of QPM in poultry for its commercial exploitation as a feed material.

Like other chick quality parameters, hatchling length is an easy and repeatable quality evaluation parameter for newly hatched chicks. This important trait has a positive correlation with the size of the egg and the chick's weight. The hatchling length is the best indicator of pre-incubation and incubation conditions and for the rate of absorption of yolk after hatching in the body cavity of the chick. Chicks with large lengths have heavier heart weights, liver weights and bursa of Fabricius at hatch. The length at hatch can be measured from the crown to toe and it can be improved by maintaining embryo temperature until internal pipping, proper egg storage conditions, maximum turning of eggs, maintaining the minimum egg weight losses at the 18th day of embryonic development, maintaining ample O2 supply and removal of CO2 through gas exchange programs, improved shell quality and better health of the breeder flock.

The yolk does not play any role in the bird's future growth but it can create many disease problems in the bird's life. A bigger, day-old chick has a large residual yolk and a small yolk-free body mass. This characteristic does not play any role in the development and growth during the incubation and post incubation processes. In conclusion, hatchling length offers a fast, repeatable, and non-destructive method to evaluate chick quality.

Ladakh, the Trans Himalayan part of the Jammu Kashmir State of India, is located between the Greater Himalaya and the Karakoram Range, known as the ‘cold desert’, and is comprised of two districts, Leh (45110 km2) and Kargil (14,086 km2). This area has several peculiar climatic conditions characterised by prolonged sub-zero temperatures, unfertile sandy soils with very low water holding capacities, dryness (less than 30% humidity), low oxygen content, intense solar radiation, low atmospheric pressure, high wind velocity and rugged terrain. In winter the temperature falls to -35°C and the altitude varies from 10,000 to 12,000 feet from mean sea level (MSL). The atmospheric oxygen pressure is 30% lower than of MSL. This type of cold arid desert isn't akin to the natural environment of poultry, and hatchability is a big problem due to the climatic conditions in this region. For normal hatchability at sea level, the oxygen concentration, barometric pressure, humidity and temperature should be 21%, 740 mm Hg, 65% and 99.8°F, respectively. However in this cold desert area O2 concentration is 30% lower than at sea level, barometric pressure is only 510 mm Hg, humidity is less than 30% and temperature ranges from -30C to +30°C.

In the last two decades, India has reached a level of self-sufficiency in chicken production, and the poultry industry has become more sophisticated, but the situation in the cold arid part of Leh-Ladakh in India remains challenging. The main reasons for this are the non-existence of any commercial hatcheries, problems transporting day old chicks, poor availability of poultry feed ingredients and the fact that the majority of the population are Buddhist, and consequently largely vegetarian and generally avoid killing animals. The following paper reviews some of the issues of raising poultry in such inhospitable conditions, and how these can be resolved.

The process of growth and development of any business entity is tightly linked to investments. This paper elaborates on the application of multiple criteria methods from the Analytic Hierarchy Process (AHP) with the aim to create assumptions for the development of production, particularly focused on opportunities for investments in table egg production. There were two alternatives analysed: investment in enriched cages and investment in alternative production systems. Each of these options had advantages and disadvantages, that were graded by criteria. Investment in alternative systems was assessed as a better alternative, as eggs produced in these systems were estimated to achieve higher income. Financial investments in such systems are higher, but eggs achieve a higher price in the market than those from enriched cages. Sensitivity analysis presented the effects that changes in the egg price and in costs structure have on the net present value of investment. Sensitivity analysis showed that changes in egg price significantly affect the success of business, while input costs have less impact on the business result.

Mycoplasma are a successful group of pathogens because of their ability to enter and colonise a host, whilst, at the same time, evading the bird's immune response. Mycoplasma iowae (MI) is no exception and, while mostly being a pathogen of turkeys, it can be found in other domestic poultry. It has the added ability of being able to induce a transient immune suppression situation, and this may result in a low to undetectable humoral immune response, giving it the capacity to conceal itself from the immune system. This makes MI both difficult to diagnose and control. The organism has a range of strain dependent pathogenicities and when it is pathogenic, it is primarily found in the embryo and growing poult. This leads to a range of clinical presentations such as decreased hatchability (due to higher than expected embryonic mortality) and stunting and leg abnormalities in the growing poult. As a consequence of the significant variation in pathogenicity of field strain isolates, the isolation of a non-pathogenic MI may conceal the true origin of possible embryo and poult health issues. Control of pathogenic MI at the commercial level is primarily through sourcing pathogenic MI free stock and the maintenance of appropriate biosecurity levels.

The present study was conducted to document the rearing practices of village chicken production in the Northern midlands, agro-ecological zone comprising Kannur and Kozhikode districts of Kerala state, India. Data was generated from 65 and 63 chicken farming families of Kozhikode and Kannur districts respectively. The system of chicken rearing is extensive, with the provision of shelter only during the night. The birds are being managed mostly by women (89.06%). The decision on the sale of birds and eggs is made by women and the proceeds of sales go directly to them. It was found that as many as 43.75% of the chicken farmers in these areas have no other animal husbandry activities. The average flock size is 5.62 birds. Natural incubation using locally available materials as a nest box and sand as the nesting material is the common practice. The average number of eggs set under the broody hen for hatching is 10.41. Chicken coops are placed at an average distance of 5.45m from the house and elevated 0.39 m from the ground. The average floor area of the coops is 0.757 m2 and the night shelter provided per bird is 830.39 cm2. The walls and floor of the coops are made of wood and the roof with tiles or thatch in most of cases. Rice grain is commonly fed as supplementary feed with mostly no specific timing in feeding. Farmers depend on an array of herbs rather than chemotherapeutic agents and vaccines for the treatment and control of diseases. Most of the surplus males (59.38%) are discarded before one year of age, whereas females are less commonly culled (21.87%). The average culling age of males and females was 11.05 and 36.64 months, respectively. It was discovered that as high as 52.15% of the eggs and 59.38% of the cockerels produced are consumed in the home. When sold they attract at least a two-fold higher price compared to birds of industrial origin.

Research results and facts about indigenous Muscovy duck production in Nigeria are reviewed with the aim of assessing its current status and delivering relevant information to stakeholders and other potential beneficiaries. There are large variations in phenotypic and biochemical characteristics of indigenous Muscovy ducks in the country, which could serve as a basis for genetic improvement. These ducks have the potential for a mean live weight of 2.73 and 1.52 kg and dressing percentage of 71.2% and 69.8% for drakes and ducks, respectively. Under scavenging, backyard farming conditions, the ducks can lay between 60 and 80 eggs each per year, and about 100 and 125 eggs per bird per year with an egg weight of about 72g under improved management conditions. The morphological, meat and egg attributes of local Muscovy ducks may be exploited in management decisions geared towards ensuring an increase in productivity, thereby making an important contribution to food security in a developing economy.

The World’s Poultry Science Journal is indebted to Prof J.A. Castello, Prof D.K. Flock, Dr D. Grastilleur, Dr S. Cherepanov and Prof N. Yang for the translations of these summaries.