Egg Production In Layers Research Articles

Informal Nutrition Symposium Biological limits to productivity

SUMMARY There will obviously be biological limits to productivity in terms of growth rate of meat birds and egg production in layers and breeding stock. We continue to see an unprecedented increase in commercial performance, and to date, we have managed to accommodate this everincreasing potential as provided by the poultry geneticists. In many situations, we do not see the full genetic potential at the poultry farm because of myriad factors that negatively affect productivity compared with maintaining these birds under small-scale experimental conditions. Under such ideal conditions, we have realized 345 eggs in 365 d in some strains of white-egg layers, whereas handling individual broilers during trials has resulted in weights of almost 4 kg at 42 d. These values therefore represent the true genetic potential of these birds and suggest that we are nowhere near the biological limit to productivity in commercial flocks of layers, broilers, or turkeys. It is not the intent of this review to discuss the reasons for “reduced” commercial productivity; rather, the goal is to discuss potential factors that may influence the absolute biological limits to performance inherent today and, more important, in the future.

Intensive versus extensive management systems in commercial egg production.

Abstract Despite the degree of environmental protection and economic feasibility offered by traditional poultry production systems, the practice of housing laying hens in cages has been widely criticized worldwide because of the public perception that caged housing systems provide poor welfare for laying hens. As a result of increasing public interest in laying hen welfare, alternative management systems such as free-range environments have been resurrected and new legislation such as the California Proposition Two is expediting a shift back towards extensive practices. The transition from intensive back to extensive practices coupled with the advent and increasing popularity of novel alternative layer housing management methods in recent years necessitates an examination of the influence of environmental stressors associated with different housing methods on layer egg production, immunological response and reproductive well-being. In this review, the evolution of intensive and extensive management practices is comparatively examined based on how these different management practices impact layer hen well-being and productivity. Different welfare assessment techniques are also examined in an effort to provide insight into the progression of research concerning layer hen welfare in different management systems.

Evaluation of egg production in layers using random regression models

The objectives of this study were to estimate genetic parameters for egg production over the age trajectory in 3 layer lines, which represent different biotypes for egg production, and to validate the use of breeding values for slope as a measure of persistency to be used in the selection program. Egg production of more than 26,000 layers per line from 6 consecutive generations were analyzed with a random regression model with a within-hatch-nested fifth-order fixed-regression polynomial and linear polynomials for random additive genetic and permanent environmental effects. Daily records were cumulated into biweekly periods. In all lines, a nonzero genetic variance for mean and slope and a positive genetic correlation between mean and slope were estimated. Genetic variance of egg production by 2-wk period was low at the beginning of lay and increased as the birds aged for all 3 lines, which resulted in heritability estimates increasing with age. Breeding values for slope reflected the shape of the egg production curve well and can be used to directly select for persistency of egg production.

Some hematological changes in chickens infected with ectoparasites

The study was conducted to identify different ectoparasites infesting 280 chicken (native breed out door house reared layers, 6 months – 2 years old), from various regions of Mosul city (poultry market, Hadba' Flock, and six flocks at Kogialli village), for one year. Total percentage of ectoparasites in chickens were 19.3 % of which (54 positive case out of 280 chicken) 81% were single infections and 19 % mixed infections. Lice infestation (12.5 %) and four types of chewing lice were classified (Menacanthus stramineus , Cuclotogaster hetrographus , Goniocoteus gallinae , and Columbicola columbae ). One species of flies (1.4%) ( Pseudolynchia canariensis ). One species of mites (4.3%) ( Dermanyssus gallinae ) were seen. One species of soft ticks (6.8%) ( Argas persicus ) were seen. Parasitological findings of skin and feathers examination for all types of ectoparasites on chicken showed three degrees of infestation depending on the number of these ectoparasites on each bird (low degree 1–50/ bird, moderate degree 51–100/ bird, and heavy degree more than 100/ bird). Clinical signs of the infected chicken with ectoparasites especially severe infection were itching, annoyance, loss of sleep, general weakness, loss of appetite, restless, allergy, drop of egg production in layers and anemia. It clear from results of blood examinations the presence of anemia in infected birds blood sucking ectoparasites with significant decrease in PCV % , TRBC and Hb concentration in chicken especially in severe (heavily) infestation with soft ticks and mites. Results also showed increase in total white blood cells (Leucocytosis) with increase in heterophils, and eosinophils in infected chicken with ticks, mites and lice, with bad nutrition and unhygienic management as compared with non-infected chicken control group.

Detection of mortality clusters associated with highly pathogenic avian influenza in poultry: a theoretical analysis

Rapid detection of infectious disease outbreaks is often crucial for their effective control. One example is highly pathogenic avian influenza (HPAI) such as H5N1 in commercial poultry flocks. There are no quantitative data, however, on how quickly the effects of HPAI infection in poultry flocks can be detected. Here, we study, using an individual-based mathematical model, time to detection in chicken flocks. Detection is triggered when mortality, food or water intake or egg production in layers pass recommended thresholds suggested from the experience of past HPAI outbreaks. We suggest a new threshold for caged flocks--the cage mortality detection threshold--as a more sensitive threshold than current ones. Time to detection is shown to depend nonlinearly on R0 and is particularly sensitive for R0<10. It also depends logarithmically on flock size and number of birds per cage. We also examine how many false alarms occur in uninfected flocks when we vary detection thresholds owing to background mortality. The false alarm rate is shown to be sensitive to detection thresholds, dependent on flock size and background mortality and independent of the length of the production cycle. We suggest that current detection thresholds appear sufficient to rapidly detect the effects of a high R0 HPAI strain such as H7N7 over a wide range of flock sizes. Time to detection of the effects of a low R0 HPAI strain such as H5N1 can be significantly improved, particularly for large flocks, by lowering detection thresholds, and this can be accomplished without causing excessive false alarms in uninfected flocks. The results are discussed in terms of optimizing the design of disease surveillance programmes in general.

Entry Barriers in Rural Business

Market liberalisation should ideally enhance the chances for development of rural business. Yet, entry barriers in poor areas are still high and local resources like land and labour, remain underutilised. This article searches for reasons behind entry barriers in one specific business, in rural Indonesia, namely layer egg production. In Indonesia, the poultry business is strongly concentrated in Java, and the huge populations on other islands are practically without commercial egg producers. Egg prices in these regions are therefore high and quality is low. The research is based on fieldwork in five of Indonesia's islands: Java, Bali, Lombok, Sumbawa, and Flores. Traditional entry barriers, like capital costs, economies of scale, brand loyalty, and technological development, are found to be low. Main explanations for the lack of entry by small-scale entrepreneurs are: limited information and knowledge; uncertainties due to the concentration and market dominance by powerful business groups. The gap is wide between those who know and control and those who do not. Lowering entry barriers into layer egg and feed production is mainly a matter of increasing competence at the household level, but institutional changes are also required. Government institutions should play a stronger role in competence development, and local cooperatives could facilitate stable supply of quality feed.

Cottonseed Meal in Poultry Diets: A Review

The residue of cottonseed oil extraction industry popularly known as cottonseed meal (CSM) is a fairly good source of protein (222.0 to 560.2gkg-1) and metabolizable energy (7.4 to 11.99MJkg-1). The use of CSM in poultry diet is limited due to the presence of gossypol, cyclopropenoid fatty acids (CPFA), high fibre and poor protein quality. The most critical amino acid in CSM is lysine. During the oil extraction from cotton- seeds, a portion of free gossypol (FG) binds with the epsilon amino group of lysine, thereby reducing the availability of lysine to the chicken. The concentration of nutrients, FG, CPFA in CSM depends on the variety of cultivars, methods of oil extraction, proportion of kernel to husk, lint and seed coat. The concentration of FG in various varieties of CSM ranges from 200 and 5300mgkg-1. In glandless variety, the FG concentration is less (>130mgkg-1). Gossypol inhibits the activity of pepsin and trypsin in gastro-intestinal tract, thereby reducing the digestibility of protein. The reported toxic effects of gossypol are growth depression, lameness, decreased egg size and hatchability. Gossypol and CPFA also deteriorates the internal egg quality by causing yolk mottling and pinkish discoloration of albumen, respectively. The tolerance levels of FG in birds vary widely depending on the age and strain of birds, protein content and quality, duration of feeding, presence of minerals especially the iron content in the diet. The tolerance of FG in chicks varies widely (90 to 1000mgkg-1 diets), however performance of layer chicks could be affected even at a lower FG intake of 2.02mg day-1 bird-1. Though, growth was not affected in broilers at FG concentration in diet below 150mgkg-1, feed efficiency was reduced at lower levels i.e. 60-100mgkg-1. The depression in egg production in layers fed diets containing more than 100mgkg-1 was mainly due to lowered feed intake. The egg weight and egg quality was not affected at FG levels upto 200mgkg-1 diet. Iron treatment (4 : 1; Fe : FG) proved to be effective in alleviating the negative effects on egg quality, but could not alleviate the depression in laying performance. Lysine supplementation to CSM containing diets is also effective in counteracting the ill effects of FG in chicken, especially chicks and broilers. Other processing methods like solid substrate fermentation, production of glandless cotton seed and use of organic solvents were though effective in improving the nutritive value of CSM and reducing the FG content in CSM, these methods are of little practical relevance and uneconomical. Production of glandless variety of cottonseed through genetic modification (Bacillus thuringiensis cotton) is one of the recent trends of reducing the FG content. Some other methods like pelleting, extrusion, cooking and Ca (OH)2 treatment of CSM could be tried for improving the feeding value of CSM in poultry.

The effect of dietary inclusion of Mansonia altissima on egg production and fertility of laying hens

An experiment was conducted in Port Harcourt to determine the effect of dietary inclusion of Mansonia altissima on egg production and fertility of laying hens, using a total of 45 birds consisting of 36 layers and 9 cocks in a randomized block of groups A, B, C of 15 birds each. Each treatment group was replicated thrice each containing 5 birds of both sexes (4 females and 1 male). Birds in group A were used as control while those in treatments B, C were fed M. altissima powder at the rate of 30 and 50 g per kg feed daily, respectively, for eight weeks. Results showed a significant difference (P<0.05) in egg production with group C showing the highest egg production but decreased fertility. It was therefore concluded that M. altissima can be used to increase egg production in layers at the level of 50 g/kg feed but the reduced fertility, which it causes should be borne in mind while doing so.

Integrating Poultry into a Crop and Pasture Farming System

Small scale operations in which poultry forage freely around farms is widespread on rura l properties. In Australia grain farmers, market gardeners and graziers integrate poultry into their farming system. In this system, birds are unrestricted in their movements except that they are usually locked in sheds at night for protection from predators. Consumers pay a premium for eggs and chicken meat on the grounds of enhanced welfare of birds in this system. Eggs are perceived as having superior taste and nutritional properties. The purpose of this experiment was to determine the impact of poultry integrated into a pasture and crop rotation system. The pasture availability, insects, weeds and soil fertility were measured before and after grazing by poultry. Sheep were used as a comparison in the experiment. Laying hens stocked at 110/ha (compared to sheep-stocking density 12/ha) were allowed to forage a medic pasture in a crop and pasture rotation system during summer in a Mediterranean environment. The egg production of layers (Hyline Brown) in the free-range system was lower than the standard performance expected in a cage system. Rate of lay from 18-40 weeks was 79% vs 93% (cage standard). The mortality of free-range birds was higher than the cage standard (9.1 vs 1.2%). The reduction of performance of birds relative to the standard was expected considering the heat wave conditions experienced during the experiment. Sheep were very effective in grazing the wire seed, which contaminated the paddocks whereas poultry avoided this weed. In contrast, the number of unidentified weeds in the sheep paddocks was greater than the poultry paddock. This raises the possibility that sheep and poultry could be grazed together in some circumstances, to provide a method for reducing weed build up. Sheep could be used to graze out weeds they prefer and poultry to consume weed seeds and insects that sheep avoid. Soil fertility was not different between the sheep and poultry paddocks. The yield of wheat from poultry paddocks in the subsequent crop was 1.25 tonne/ha versus 1.43 tonnes/ha from sheep paddocks.

Effects of the Feeding of Iodine Additives on Qualities and Production of Eggs in Layers

This experiment was to determine the effects of the feeding of three different types of organic or inorganic iodine additives on the contents of iodine and cholesterol in eggs and egg production in layers. The iodine content in yolk increased rapidly 4 days after the feeding of the additives. At 9-11 days later it reached to the maximal levels (19-23μg) which were about 60-70 times compared with those of the control group and were maintained during the feeding of the additives. When the feeding of the additives was suspended, the iodine content in yolk decreased sharply 5 days later and reached to almost the same levels as those of the control group 9 days later. The iodine content in albumen also increased gradually reaching to the maximal levels (0.6-1μg) 5 days after the feeding of the additives. It reached to the same levels as those of the control group 4 days after suspending the feeding of the additives. It is suggested that iodine fed additionally to layers is accumulated both in yolk and albumen, but the degree of the accumulation is much higher in yolk than albumen.There was no difference in iodine accumulation in the eggs among three different types of iodine additives used. The content of cholesterol in yolk and laying performance was not affected by the feeding of the additives.

Forced Molting in Pullets and Its Effect on Subsequent Egg Production in Layers

Effects of forced molting induced by methalibure administered either at 3 months or 7 months after the age of 50% egg production upon subsequent egg production were investigated.In the group treated at earlier age the level of egg production after the recovery from temporal cessation of egg laying was more or less similar to that of non-treated control, while the group treated at older age showed a marked rebounding of egg production and continued higher production level throughout the testing period (Fig. 2).Approximately 10% increase in the income through egg marketing can be expected by the use of forced molting conducted at 7 months after the age of 50% production, when the price of eggs is lowest.The degree of molting by methalibure administration seems to be dependent on the age of pullets or the stage of egg production, since the molting appeared in the primary feather was less severe in the group treated at the earlier age and the recovery to 50% production was hastened in this group in comparison with the group treated 4 months later.

Effect of Alfalfa Saponin on Laying Chickens

COONEY, Butts, and Bacon (1948) found that dehydrated alfalfa meal had a depressing effect on the growth, diet consumption, and diet utilization of chicks. Lepkovsky et al. (1950) reported that dehydrated alfalfa meal contains a naturally occurring substance (or substances) that depresses the growth of chicks, and that its fiber is not the offending substance.The experiments of Heywang (1950) indicate that both dehydrated and suncured alfalfa meals may contain a factor (or factors) that retard not only the growth of chicks but also the egg production of layers. He also observed that alfalfa meals may vary considerably in their retarding effects, and thus in the amount of responsible factor.According to Peterson (1950) the growth inhibiting effect of Quillaja saponin is similar to that of dehydrated alfalfa meal. Consequently, his results indicate that the growth inhibiting effect of alfalfa might be due to saponin.Heywang and Bird (1953) fed …

The Effect of Alfalfa Saponin on the Growth, Diet Consumption, and Efficiency of Diet Utilization of Chicks

IN THE experiment of Cooney, Butts and Bacon (1948) each addition of 5 percent dehydrated alfalfa meal to the diet above the 5 percent level had an increasingly depressing effect on the growth, diet consumption, and diet utilization of chicks. Lepkovsky, Shaeleff, Peterson and Perry (1950) reported that dehydrated alfalfa meal contains a naturally occurring substance (or substances), probably organic in nature, that depresses the growth of chicks and that the fiber in alfalfa meal is not the offending substance.The experiments of Heywang (1950) showed that both dehydrated and suncured alfalfa meals may contain a factor (or factors) that retards the growth of young chickens and the egg production of layers when they are included in the diet at levels as low as 10 percent. He observed that alfalfa meals may vary considerably in their growth depressing effect, which seems to explain why some investigators have reported that the …