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This paper, the second from a comprehensive study, describes the effects of varying growth rate by feeding at different planes of nutrition with a constant ME:CP ratio on muscle characteristics and meat quality in 2 distinct broiler breeds of male chickens (Arbor Acres, a commercial line; and Beijing-You, a Chinese nonimproved line). Experimental diets, differing on average by 2% CP, were formulated with high-, medium-, or low-nutrient densities for 3 growing phases. Male hatchlings (216 of each breed) were randomly assigned to 6 pens of 12 birds in each treatment. Altered histological characteristics of muscle fibers, early postmortem muscle metabolism, and meat quality were investigated in the pectoralis major and biceps femoris. At their market age, Arbor Acres broilers had significantly higher concentrations of plasma protein and lipid metabolites, ratios of white to red and intermediate fibers, pH, L* and b* values, and lower concentrations of plasma glucose metabolites, muscle-fiber diameter, muscle contents of energy stores, a* value, drip loss, and shear force than the values found for the Beijing-You chickens (P < 0.01). Higher nutrient density increased the size of the muscle fibers, decreased glycogen reserve, and reduced the rate and extent of acidification in the Arbor Acres chickens, while accelerating transformation of red and intermediate-to-white fibers, enhancing energy stores, and hastening the decrease in pH postmortem in the Beijing-You chickens (P < 0.05). In each breed, most meat quality variables (e.g., shear force, drip loss, and color) were consistent with the histological and biochemical changes caused by the feeding strategy. Together, dietary nutrient density can influence meat quality as a result of altered histological and initial energy and metabolic characteristics of the muscle. Many of the responses to diet are breed and tissue dependent in broiler chickens.

This paper summarizes the results from 3 simulated in-house catastrophic mortality composting experiments. Experiment 1 evaluated the impact of water-based foam mass depopulation on in-house composting of the carcasses and litter and showed that water-based foam improved windrow temperatures. Experiment 2 evaluated the impact of freezing samples on virus recovery from windrow compost tissue and the choice of tissue for virus sampling within the bird. Experiment 2 documented that freezing the samples had minimal impact on processing and that virus recovery was more consistent among inoculated breast meat than inoculated tracheas. Experiment 3 evaluated the impact of sawdust, straw, and sawdust-straw base layer litter material on in-house mortality composting. All litter materials were able to reach and maintain temperatures in excess of 60°C for multiple days. No viral hemagglutination activity was observed after d 2 during any of the 3 experiments.

A LITERATURE review summarizing available research data on restricted feeding programs for replacement pullets has been made by Wolf (1965). The data which have been obtained are often inconsistent and contradictory. A more basic approach needs to be made in studying the nutrient intake requirements of replacement pullets in which consideration is given to food intake and the factors which control food intake. The individual physiological mechanisms through which food intake is regulated and controlled have been summarized in a review paper by Anand (1961). The basic findings from this area of research (insofar as they involve dietary protein, dietary energy, dietary volume, and dietary weight) have been applied in the feeding trial with replacement pullets which is reported in this paper. EXPERIMENTAL PROCEDURE General Design. The experimental design and the treatments imposed in this experiment are outlined in Table 1. The entire experiment covered a span of 64 weeks…

This paper is concerned with the effects of photoperiod on ovarian morphology and carcass traits at sexual maturity in egg-type hens. Two hundred fifty-six commercial egg-type pullets were initially subjected to a photoperiod of 23L:1D, which was reduced to 22L:2D at 1 wk, to 18L:6D at 2 wk, and to 16L:8D at 3 wk. From 4 to 20 wk, the photoperiod was 8L:16D. At 20 wk, 32 pullets were individually caged in individually lit cages, with 8 cages per unit. Two cage units were placed into 4 photoperiods of 17L:7D, 15L:9D, 13L:11D, and 11L:13D, respectively. Each bird was processed when it reached sexual maturity (SM), and carcass and ovarian morphology were assessed. The results showed that photoperiod had an effect on the timing of SM, and the age at first egg was 5.7 d earlier for hens exposed to the 17L:7D photoperiod than the 11L:13D photoperiod. However, photoperiod had no effect on BW at SM. A photoperiod of 11L:13D limited ovarian follicle formation and increased carcass protein and lipid compared with birds on longer photoperiods, whereas the 17L:7D photoperiod restricted ovary and oviduct full development. These results indicated that excessively long and short photoperiods can restrict reproductive development in egg-type hens.

To comprehensively assess conventional vs. some alternative laying-hen housing systems under U.S. production conditions, a multi-institute and multi-disciplinary project, known as the Coalition for Sustainable Egg Supply (CSES) study, was carried out at a commercial egg production farm in the Midwestern United States over two single-cycle production flocks. The housing systems studied include a conventional cage house (200,000 hen capacity), an aviary house (50,000 hen capacity), and an enriched colony house (50,000 hen capacity). As an integral part of the CSES project, continual environmental monitoring over a 27-month period described in this paper quantifies indoor gaseous and particulate matter concentrations, thermal environment, and building ventilation rate of each house. Results showed that similar indoor thermal environments in all three houses were maintained through ventilation management and environmental control. Gaseous and particulate matter concentrations of the enriched colony house were comparable with those of the conventional cage house. In comparison, the aviary house had poorer indoor air quality, especially in wintertime, resulting from the presence of floor litter (higher ammonia levels) and hens' activities (higher particulate matter levels) in it. Specifically, daily mean indoor ammonia concentrations had the 95% confidence interval values of 3.8 to 4.2 (overall mean of 4.0) ppm for the conventional cage house; 6.2 to 7.2 (overall mean of 6.7) ppm for the aviary house; and 2.7 to 3.0 (overall mean of 2.8) ppm for the enriched colony house. The 95% confidence interval (overall mean) values of daily mean indoor carbon dioxide concentrations were 1997 to 2170 (2083) ppm for the conventional cage house, 2367 to 2582 (2475) ppm for the aviary house, and 2124 to 2309 (2216) ppm for the enriched colony house. Daily mean indoor methane concentrations were similar for all three houses, with 95% confidence interval values of 11.1 to 11.9 (overall mean of 11.5) ppm. The 95% confidence interval values (overall mean) of daily mean PM10 and PM2.5 concentrations, in mg/m3, were, respectively, 0.57 to 0.61 (0.59) and 0.033 to 0.037 (0.035) for the conventional cage house, 3.61 to 4.29 (3.95) and 0.374 to 0.446 (0.410) for the aviary house, and 0.42 to 0.46 (0.44) and 0.054 to 0.059 (0.056) for the enriched colony house. Investigation of mitigation practices to improve indoor air quality of the litter-floor aviary housing system is warranted.

Enteric disorders predispose poultry to malnutrition. The objectives of this paper were 1) to simulate the inanition of poult enteritis mortality syndrome by restricting feed intake and 2) to develop a drinking water supplement that supports the immune functions of poults with inanition. Poults were restricted to 14 g of feed/d for 7 d beginning at 14 d of age then fed ad libitum until 36 d (recovery). The control was fed ad libitum. During the feed-restriction period, duplicate groups of 6 poults received 1 of 5 drinking water treatments: 1) restricted feed, unsupplemented water; 2) restricted feed + electrolytes (RE); 3) RE + glucose + citric acid (REGC); 4) REGC + betaine (REGCB); or 5) REGCB + zinc-methionine (REGCBZ). Immunological functions were assessed by inoculating poults with SRBC and B. abortus (BA) antigen at 15, 22, and 29 d of age. Antibody (Ab) titers were determined 7 d later for primary, secondary, and recovery responses. The primary and secondary total Ab titers to SRBC for restricted feed were 4.71 and 6.16 log3, which where lower (P < 0.05) than for controls (8.00 and 9.66 log3) and the other treatments. The recovery Ab titer for controls was 10.7, significantly higher than restricted feed (8.71) and RE (8.10) groups but not different from other treatments. The primary total Ab responses to BA were significantly lower in the restricted feed and RE groups as compared with the control and other treatments. Although feed restriction of poults to maintenance reduces the humoral immune responses, these responses can be significantly improved by drinking water containing electrolytes and especially sources of energy such as glucose and citric acid.

Natural antibodies (NAb) are an important component of the first line of immune defense. Selective breeding for enhanced NAb levels in chickens may improve general disease resistance. It is unknown what the consequences of selection for NAb will be on the productive performance of laying hens. In this paper we describe the genetic relations between NAb titers binding keyhole limpet hemocyanin at 19 wk age and production traits in a white purebred leghorn chicken line observed in several time periods. A linear animal model was used to estimate (co)variance components, heritabilities, and correlations. Negative genetic correlations were found between egg weight and NAb titers, and between egg breaking strength and NAb titers. Positive genetic correlations were found between the feed conversion ratio (consumed feed/egg mass produced) and NAb titers, and egg production and NAb titers. Negative phenotypic correlations were found between body weight and NAb titers, between egg weight and NAb titers, and between egg breaking strength and NAb titers. Positive phenotypic correlations were found between egg production and NAb titers, and feed conversion ratio and NAb titers. In general, phenotypic correlations were more often significant, but less pronounced than genetic correlations. Other production traits were not found to be significant related to NAb titers. These findings suggest that there is a genetic tradeoff between levels of immunity and some production traits, although the underlying mechanism(s) remain(s) unclear. The results suggest possible consequences for production efficiency as a result of selective breeding for improved general disease resistance by natural antibodies.

This study estimated the genetic variance components of P utilization in Japanese quail. A parental generation was assembled from an unselected random-bred Japanese fattening quail line. Seven sires and 14 dams were randomly selected, and each sire was paired with 2 dams to produce full and half sibs. A total of 200 unsexed 1-d-old quail with known pedigree were wing-banded and raised during the first 4 d posthatch in groups in floor pens on wood shavings and fed a preexperimental diet that was adequate in all nutrients. Starting on d 5, quail were individually housed in metabolic compartments on P-free filter paper. This started a balance trial with 5 d of adaption and 5 d of total excreta collection. During this balance period, all quail were fed a low-P (3.9 g/kg of DM) corn-soybean meal-based diet with a Ca:P ratio of 1.6:1.0. Phosphorus and Ca utilization were determined individually using the difference in P or Ca intake and the total P or Ca excretion. The average P utilization was 72% and the average Ca utilization was 63%, each with very high variation. Heritabilities were estimated to be 0.09 (SE = 0.09) for P utilization and 0.09 (SE = 0.09) for Ca utilization. Heritabilities were close to the values reported in the literature for broilers and suggest that quail are suitable as a model animal. The SE of the heritability estimates were large. This implies that further studies with a larger sample size are needed to identify genetic and physiological mechanisms that influence P and Ca utilization in Japanese quail.

Rubin, Bird, and Rothchild (1946) reported that hen feces contained a factor essential for maximum growth of chicks fed a cereal grain-soybean oil meal diet containing adequate amounts of the known growth factors. The discussion in the paper by Rubin et al. (1946) indicates that these workers believed the chick growth factor was synthesized in the intestinal tract of the hen. However, it was pointed out that the possibility of synthesis after voiding of the feces could not be ruled out. Since no description of the manner of collecting the feces or the time and temperature of holding before drying was given in the paper by Rubin et al. (1946) it was considered desirable for us to determine whether fecal material reduced to temperatures too low for bacterial growth immediately after voiding would contain chick growth promoting properties. Feces were collected from White Leghorn hens kept in an unheated house . . .

The effects of heating of eggs during storage, broiler breeder age, and length of egg storage on hatchability of fertile eggs were examined in this study. Eggs were collected from Ross 344 male × Ross 308 broiler breeders on paper flats, held overnight (1 d) at 18°C and 75% RH, and then transferred to plastic trays. In experiment 1, eggs were obtained at 28, 38, and 53 wk of flock age. During a further 10 d of storage, eggs either remained in the storage room (control) or were subjected to a heat treatment regimen of 26°C for 2 h, 37.8°C for 3 h, and 26°C for 2 h in a setter at d 5 of storage. In experiment 2, eggs from a flock at 28 wk of age were heated for 1 d of a 6-d storage period. Eggs from a 29-wk-old flock were either heated at d 1 or 5 of an 11-d storage period in experiment 3. In experiment 4, 27-wk-old flock eggs were heated twice at d 1 and 5 of an 11-d storage period. Control eggs stored for 6 or 11 d were coincubated as appropriate in each experiment. Heating eggs at d 5 of an 11-d storage period increased hatchability in experiment 1. Although no benefit of heating 28-wk-old flock eggs during 6 d of storage in experiment 2 was observed, heating eggs from a 29-wk-old flock at d 1 or 5 of an 11-d storage period increased hatchability in experiment 3. Further, heating eggs from a 27-wk-old flock twice during 11 d of storage increased hatchability in experiment 4. These effects were probably due to the fact that eggs from younger flocks had been reported to have many embryos at a stage of development where the hypoblast had not yet fully developed (less than EG-K12 to EG-K13), such that heating during extended storage advanced these embryos to a more resistant stage.

This paper provides an overview of results from a long-term (38 generations) selection experiment. Lines were developed from individual phenotypic selection for high or low body weight at 8 wk of age. Included are data for the selected lines, sublines in which selection was relaxed, crosses of the selected lines, and sublines in which the sex-linked dw gene was introduced. Periodically (and in some cases every generation) data were obtained for unselected traits. These unselected traits included feed consumption and intake behavior, reproduction, allomorphic relationships, and metabolic, immunological, endocrine, and molecular factors. These responses have been integrated into a resource allocation paradigm.

Reducing the level of nonphytate P (NPP) in diets for laying hens without negatively affecting their productivity and heath is crucial for sustainable egg production. A meta-analytical approach using a full quadratic model was applied to quantify relationships between dietary NPP and phytase levels and performance of laying hens. Egg production (EP, %), egg mass (EM, g/hen/day), and feed conversion ratio (FCR) were considered as model outputs. A data set containing 168 P or P plus phytase treatments was extracted from 12 published papers. The data were assembled from 14 trials with a total of 8,752 hens in the range of 36 to 76 wk of age. The EP, EM, and FCR were analyzed using a linear mixed model that included the linear and quadratic effects of dietary NPP and phytase levels and their interactions. Except for the quadratic effect of dietary phytase on FCR, all other model components (that is, intercept, linear, quadratic, and interactions) were significant (P

The objectives of this paper were to identify the phenotypic egg-laying patterns in a White Leghorn line mainly selected for egg production, to estimate genetic parameters of traits related to egg production and to evaluate the genetic association between these by principal components analysis to identify trait(s) that could be used as selection criteria to improve egg production. Records of 54 wk of egg production from a White Leghorn population were used. The data set contained records of the length:width ratio of eggs at 32, 37, and 40 wk of age; egg weight at 32, 37, and 40 wk of age; BW at 54 and 62 wk of age; age at first egg; early partial egg production rate from 17 to 30 wk and from 17 to 40 wk of age; late partial egg production rate from 30 to 70 wk and from 40 to 70 wk of age; and total egg production rate (TEP). The estimates of genetic parameters between these traits were estimated by the restricted maximum likelihood method. Multivariate analyses were performed: a hierarchical cluster analysis, a nonhierarchical clustering analysis by the k-means method of weekly egg production rate to describe the egg-laying patterns of hens, and a principal components analysis using the breeding values of all traits. The highest heritability estimates were obtained for BW at 54 wk of age (0.68 ± 0.07) and age at first egg (0.53 ± 0.07). It is recommended that a preliminary clustering analysis be performed to obtain the population structure that takes into account the pattern of egg production, rather than the TEP, because hens may have the same final egg production with different patterns of egg laying. Early partial production periods were not good indicators for use in improving total egg production because these traits presented an overestimated genetic correlation with TEP because of the part-whole genetic correlation component. Egg production might be improved by selecting individuals based on TEP.

Broiler litter (manure plus bedding) represents the single largest waste by-product generated by the broiler industry. In 1990, 5.86 billion broilers were produced in the United States (National Agricultural Statistic Service, USDA). On a dry-weight basis, using averages cited in the present paper for litter (1.0 metric ton per 1,000 broilers per flock) and nutrient composition (3.88% total N, 4.25% P2 O5, and 2.68% K2 O), the total annual United States broiler nutrient production is estimated at 227,368, 249,050, and 157,048 metric tons of N, P2 O5, and K2 O, respectively. However, there are substantial variations in both litter production rates and composition values among reports that can greatly influence these estimates. Litter rates and values are influenced by amount and type of bedding, frequency of removal, broiler market weights, nutrition and feed utilization efficiency, and numerous management factors. Understanding these sources of variability is helpful in the implementation of strategies for litter enrichment. In the future, a totally integrated approach may be necessary for the production of litter that is designed for specific applications and markets.

Northern fowl mites (NFM) are external parasites that can lower egg production and cause anemia and even death in laying hens. An experiment was conducted with New Hampshire Red and Single Comb White Leghorn laying hens. Hens were individually caged and provided a complete laying diet and water ad libitum. Hens were assigned to groups in a way that assured that treatments, within each breed, would be applied to comparable numbers of birds with light and heavy mite infestations. Each hen was sprayed around the vent with either water or 10% garlic juice in water. Spraying continued each week for 3 wk. During the fourth week, each bird was scored for the presence of NFM on its skin and feathers. A small snippet of feathers was removed from below the vent of each hen and placed in a labeled petri dish with a round, white filter paper insert. The NFM content of each dish was scored by two individuals approximately 1 h after sampling. There was no significant difference in the NFM scores for hens based on breed or future treatment. After the birds were treated for 3 wk, there was no significant difference in external NFM scores based on breed. There were significantly fewer NFM on the birds treated with garlic juice compared with controls, based on external and petri dish scoring (P0.002 and P0.04, respectively). The reduction in external NFM score was also significant (P0.004), with controls declining approximately 0.2 units, whereas garlic-treated hens had a 1.8-unit decrease in external NFM score. Topical application of garlic juice may be an effective way to decrease NFM in laying hens.

Six rooms, identical and environmentally controlled, and each housing 14 caged turkey breeder hens, were exposed to light schedules to provide continuous and intermittent photoperiods of 14, 12, and 10 h as follows: 1) 14 h, continuous; 2) 14 h, intermittent; 3) 12 h, continuous; 4) 12 h, intermittent; 5) 10 h, continuous; and 6) 10 h, intermittent. Observations were made regarding: 1) the number of flies on feeders, in jug traps, on sticky fly tapes for 24 h, and sticky fly tapes for 1 h; 2) fly spots on paper sheets and fly spots on hanging cords. There were significantly (P

Beta-adrenergic agonists have been shown to be capable of improving growth performance in poultry when added to the feed at 1.0 ppm. However, no reference has been made concerning the cardiovascular responses when one of these agents is added to the feed at a lower concentration during the whole production cycle. The aim of this paper was to assess the effects on the ascites syndrome of 0.25 ppm clenbuterol in the feed, throughout 52 d, in broiler chicks. Results showed a lack of difference in growth and feed conversion rate between the untreated control groups and the experimental group. There were differences in mortality due to the ascites syndrome, abdominal fat:body weight ratio, and ventricular index. A statistically significant positive correlation was also found between ventricular index and mortality rate (r = 0.98). If adequate withdrawal times are ensured, the use of clenbuterol at 0.25 ppm is suggested to reduce mortality due to the ascites syndrome in broilers.

The research described in this paper relates the changes in serum concentration of calcium, phosphorus, and 1,25-dihydroxycholecalciferol [l,25(OH)2 D3] to changes in tibial ash percentage and the incidence of endochondral ossification defects (EOD) in flocks of commercially reared broiler chickens at 14 d of age. Sequential studies of six Australian broiler flocks representing three major genetic lines were undertaken at weekly intervals from 1 to 28 d of age. Serum collected from birds was analyzed for total calcium, inorganic phosphorus, and l,25(OH)2 D3. Tibial ash percentage was also determined at weekly intervals, and the incidence of EOD was determined at 14 d of age by examining sagittal sections of the proximal tibiotarsus. The EOD observed in the 14-d-old broiler chickens were characterized by enlarged zones of proliferating chondrocytes, similar to that which occurs during calcium- or vitamin D-dependent rickets. Three flocks had a 50% incidence of EOD at 14 d of age and were classified as severely affected. The other three flocks had incidences ranging from 12 to 16% and were classified as mildly affected. Broiler flocks severely affected with EOD (50% incidence at Day 14) had lower (P ≤ .05) concentrations of l,25(OH)2 D3 than flocks mildly affected (12 to 16% incidence). Tibial ash percentages were lower (P ≤ .05) in the severely affected flocks between Days 14 to 28, and it is likely that a lower rate of ash accretion between Days 7 to 14 precedes the development of the EOD. From these studies it is evident that flocks with a high incidence of EOD have significantly lower bone ash and 1,25 (OH)2 D3 compared with mildly affected flocks, and it seems probable that higher systemic concentrations of l,25(OH)2 D3 between 7 to 14 d of age will enhance the ability of broiler chickens to effectively mineralize the cartilaginous growth plates in the appendicular skeleton during early bone maturation.

Recently, Vazquez-Anon et al. (2006) published a paper in Poultry Science suggesting evidence for DL-2-hydroxy4-(methylthio) butanoic acid (DL-HMTBA) and DL-Met (DL-M) having different dose responses in growing broilers. The authors concluded that the 2 Met sources “have a different dose-response form, DL-HMTBA could outperform DL-M at commercial levels, and DL-M could outperform DL-HMTBA at deficient levels.” Additionally, it is suggested that relevant comparisons between the 2 Met sources should be conducted “at levels of commercial use.” These conclusions and suggestions are incorrect and misleading. When comparing essential nutrients or different sources of the same nutrient (L-Met in the present case), one should always evaluate the complete dose-response curve, starting with a deficient basal diet, followed by several incremental levels of the nutrients to be tested. Depending on the data structure of the respective dose-response trial, slope-ratio (linear response) or nonlinear models should be applied. These models can be used for estimation of comparative bioefficacy or bioavailability of any nutrients, such as P (Potter et al., 1995) or Fe (Boling et al., 1998). A simple example based on broiler weight gain data by Lemme et al. (2002) shall be used to demonstrate the statements above vs. the incorrect methodology and conclusions of Vazquez-Anon et al. (2006). Two Met sources, DL-M and diluted DL-M (65%, a product representing an internal standard with a known “relative efficacy” of 65%), were added at incremental levels to a Met-deficient commercial-type diet (Table 1). Using the proper exponential regression method to analyze the data sets, diluted DL-M (65%) had a calculated relative efficacy of 60% relative to DL-M (Lemme et al., 2002), confirming the validity of the used statistical method. Using a completely different approach to evaluate the data, the relative response rate of the basal diet was 64% of the maximum response (see Table 1). The relative response rates for the 0.06, 0.12, 0.18, and 0.24% supplemented DL-M levels were 84, 94, 99, and 100%, whereas the relative response rates for diluted DLM (65%) were 76, 86, 91, and 98%. Hypothetically, several different “effectiveness figures” were generated in this ex

This paper assesses the effects of substituting aerobically stabilized poultry manure for tap water on the performance of caged White Leghorn laying hens. Three separate feeding trials over a three-year period were conducted. In each feeding trial, aerobically stabilized poultry manure from an undercage oxidation ditch was substituted for tap water. For the three trials, egg production by the hens receiving the aerobically stabilized poultry manure exceeded that of the control group by an average of 2.6 ± 1.7%. No significant differences were observed in final body weights, mortality, or egg weights between the two groups of hens in any of the three feeding trials.

This paper examined the effect of N-correction on the true metabolizable energy (TME) values of mixed diets and single ingredients using mature White Leghorn roosters. The N-corrected TME (TMEn) values were consistently higher than the corresponding TME values, the results being significant (P less than .05) in about one-half of the samples tested. This indicated a net loss in body N in the birds during the experiments. The correlations between N input and N correction were highly (P less than .01) significant. This, however, explained only 46 to 48% of the variation in the TMEn data as being due to differences in the amount of N input. In view of the present results and the abnormal condition (fasted birds) in the TME assay, it is doubtful that birds would retain enough N from a single feeding to revert to a positive body N equilibrium. Therefore, positive N retention in such an assay would be indicative of incomplete feed passage through the birds. This appears to be the only valid reason for applying N correction to TME values. However, the variations associated with N correction of TME data raise some doubt concerning the validity of this assay as compared with the conventional apparent metabolizable energy assay.

Nine groups of 12 Small-type White turkey hens each were used to study dietary vitamin D3 and calcium and their effect on egg production, eggshell quality, and hatchability. The 3 × 3 factorial arrangement of treatments consisted of three levels of calcium (1.16, 2.25, and 3.34%) and three levels of vitamin D3 (cholecalciferol) at 900, 6,900, and 12,900 International Units per kg. of diet. Increasing dietary calcium to 2.25% significantly improved body weight, egg production and feed efficiency (feed/kg. eggs). The 3.34% level of calcium stimulated an increase in percentage hatchability of fertile eggs and produced the lowest percentage of 28-day embryonic mortalitites. Dietary vitamin D3 in excess of established requirements had no statistically significant effects on any of the parameters studied. Positive correlations were noted between beta-backscatter counts, shell weight, shell thickness and percentage calcium content of the egg. Percentage hatchability of fertile eggs was negatively associated with percentage moisture loss during the first seven days of incubation. The data presented in this paper show no beneficial action in the turkey hen from vitamin D3 fed in excess of recommendations, but dietary calcium in excess (3.34%) promoted an increase in hatchability and a decrease in embryonic mortality.

TRENDS in egg production and egg weight during the first year of production have been studied by many investigators, but data relating to the trend in hatchability appear to be somewhat scanty. This paper presents data on the average hatchability of eggs, during each month of the first year of production, from pullets receiving low-protein and normal diets, together with data on average egg production and egg weight for the same birds which have been included for purposes of comparison with the hatchability data. The data herein reported were obtained as part of a study of the effects of some nutritional factors on hatchability, conducted by the staffs of the nutrition and physiology laboratories at the U. S. Animal Husbandry Experiment Farm, Beltsville, Maryland. The observations were made over a period of three years, a different group of pullets being used each year. The experimental work was usually begun during . . .

IN A previous paper on wood sugar molasses as a feedstuff for laying hens (Cooney and Parker, 1952) it was pointed out that cane and beet molasses have been accepted and used as an ingredient in livestock and poultry rations for a good many years. The review of literature indicated that these products could be fed up to ten percent of the chicken’s total ration. However, levels of five to seven percent of the total ration seemed to be more generally accepted. McGinnis, MacGregor and Carver (1948) were the first to report on the use of molasses prepared from wood waste in poultry rations. They fed levels of 0, 5, 10, 15, and 20 percent of this product to duplicate lots of one week old New Hampshire chicks over a three-week test period. From this work they concluded that wood sugar molasses could be used in chick rations at any …

Recent studies (Motzok et al., 1967) showed that for maximum growth and bone calcification of chicks fed soft phosphate, it was necessary to supplement the diet with additional calcium (0.15–0.2% as calcium carbonate), even when sufficient soft phosphate was used to raise the level of calcium in the diet to 1.12%. These data suggested that for maximum utilization of the inorganic (available) phosphorus of the basal ingredients, about 0.2% additional calcium, in a readily available form, was required in diets supplemented with soft phosphate. This suggestion was tested in an assay procedure for estimating the relative availability of phosphorus from supplements, and the results are presented in this paper. Sufficient calcium carbonate to provide 0.2% calcium was added to the basal diet (Motzok et al., 1967) to raise the calcium level to 0.46%. Tricalcium phosphate (chemical grade) and soft phosphate were added to the basal diet containing 0.46% calcium . . .

GARDINER (1957) reported that young chickens kept in wire cages and inoculated experimentally with large numbers of sporulated oocysts of Eimeria tenella (1) did not die from cecal coccidiosis when fed growing mash medicated with sulfamethazine at a level of 0.125 percent, and (2) made weight gains equal to or somewhat better than uninfected control birds when aureomycin was added to the sulfamethazine-medicated mash at the rates of 100 and 200 grams per ton. In the above-mentioned investigation, the amount of sulfamethazine included in the feed was kept constant, whereas the amount of aureomycin was varied. The present paper summarizes results of experiments in which birds were fed growing mash fortified with a constant amount of aureomycin, namely, 200 grams perton, and medicated with sulfamethazine at levels of 0.125, 0.075, and 0.050 percent. EXPERIMENTAL PROCEDURE The chicks used in these experiments were New Hampshire-Barred Rock crosses. They were obtained from . . .

Previous papers by the author have shown that both ovarian and bodily injury caused certain fowls to lay more eggs. It was true also that other hens in the same experiment had their egg production retarded, hence a greater variability among the operated animals (Steggerda ’28 and ’30). In the present experiment the ovary of six-weeks old pullets was injured to note the effect upon the length of time until the first egg was laid. The results indicate a similar stimulation due to the operation since the operated pullets layed on the average sooner than did the control birds. The experiment was carried on at the Poultry Department of the Massachusetts Agricultural College, with birds owned by the College. The author wishes to express his thanks to Prof. J. C. Graham and Supt. John Vondell for the use of the birds and the keeping of the records, also to his . . .

POULTRY breeders interested in the improvement of egg quality would like to know how many eggs are needed to adequately evaluate the real but unknown inherent breeding worth of a hen. Some breeders feel that observations on two or three eggs per hen are sufficient, while others think that a larger number of eggs should be examined. The key to a problem of this type is based on a knowledge of the repeatability of the quality trait under consideration. Repeatability may be defined for our purposes as the correlation between observations on successive eggs laid by the same hen. The limits of repeatability (R) are between zero and one. If R is large only a few eggs per hen would be required, whereas if R is small several eggs may be required to accurately evaluate the egg quality characteristics of a hen. In a previous paper (Scheinberg et al., 1953) …

BALANCE studies of various dietary factors have been conducted with the chicken as the experimental subject, but scarcely any consideration has been given to the intake and output of fat by this species. Guntherberg (1930) has reported on the digestion of the fat of cereals by hens. The object of the present investigation was the determination of the intake and output of fat by the laying and non-laying hen on normal and low fat rations, to determine the effect of the deprivation of fat on egg production, and the extent to which the chicken can synthesize fat for egg production. EXPERIMENT 1 This experiment was planned to determine the relation between egg production and the fat consumption and output when a normal ration is fed. Throughout the paper the word “fat” is used for convenience instead of the term crude fat or ether extract, which was actually determined. Also the . . .

THE period of non-production following the first laying year is frequently referred to as the annual molt. Although the close association of cessation of egg production with the process of shedding and replacement of feathers has been adequately demonstrated (Marble, 1930), certain differences in this respect exist between birds with different production characteristics. Marble has found that in cases of higher producing individuals molting begins before production has actually stopped, while in lower producing individuals little if any molt occurs before complete cessation of laying. Thus there is no complete coincidence of molting with the period of non-production between the first and second laying years. Since no molt observations were made on the birds considered in this paper, the period of nonproduction studied is termed here the annual rest. The methods followed in the determination of the duration of this period will be described later. The factors affecting the duration . . .

THERE is evidence in the literature that calcification in the chick involves more factors than calcium, phosphorus, manganese, and vitamin D. In a recent paper Wilcke and Hammond (1940) summarized earlier investigations. Jukes (1940) found that choline was necessary for the prevention of perosis and commented that its action was more complete in the presence of pantothenic acid. Working with rats, Krieger, Bunkfeldt, and Steenbock (1940) found that the phosphorus of phytin was not readily available and that vitamin D increased its availability. In an experiment involving the use of a diet heated to destroy its pantothenic acid it was noted that if riboflavin was added, growth was improved but symptoms of severe rickets soon developed. It was soon found that if the vitamin D content of the found that if the vitamin D content of the diet was increased from 40 to 200 A.O.A.C. chick units per 100 grams . . .

THE large scale production of the many types of turkey products from whole carcasses has focused attention on the number of servings obtained per pound of turkey purchased. Since the amount of turkey used for this purpose is measured in tons, sizable economic differences may result from factors which have gone unrecognized. McCartney (1952) reported that the meat yield from Broad Breasted Bronze (BBB) was greater than that of the Beltsville Small White (SW). Orr et al. (1956) found that dressed weight yields were significantly higher for BBB than for a Medium White (MW) and the BSW, and the MW gave a significantly higher yield than the BSW. Mortenson (1960) indicated the yield for a BBB exceeded a Broad Breasted White (BBW) by less than one percent. Additional data indicating differences between turkey strains were reported by Carlson et al. (1962). The purpose of this paper is to report that . . .

WHILE many papers have been published on the use of artificial light to stimulate gonad activity among turkeys out of season, the authors have found only one experiment reported where the fluorescent tube was used as one of the sources of light. Since fluorescent tubes are used as the only source of light in many of the cage laying houses for chickens in this area, the following experiment was conducted to compare a 60-watt incandescent lamp and a 15-watt white fluorescent tube for stimulating egg production in mid-winter. Turkeys were used as the experimental birds since the sexual periodicity is fixed from year to year more in turkeys than in chickens. In this latitude (39°N.) turkeys normally do not begin laying until the first week in March unless provided with artificial light. (Scott and Payne, 1937.) These authors using information previously established by Bissonnette (1932), who worked with starlings, demonstrated . . .

APPARENTLY there are no published data on the effect of the fat content of the diet of laying chickens on the hatchability of their eggs. In order to obtain information on this subject the writer conducted two experiments, in each of which diets of different fat content were fed to laying pullets and data were obtained on the time of occurrence of embryo mortality and on hatchability. The results of these experiments and the conclusions drawn from them are presented in this paper. EXPERIMENTAL MATERIALS AND PROCEDURES The first experiment was started on October 18, 1939, and the second on November 6, 1940, For each experiment 200 White Leghorn pullets, hatched during the preceding spring, were carefully selected and distributed into eight groups. The distribution was so made that any effect the live weights of the individual pullets might have on feed consumption and egg production would be equalized among . . .

INTRODUCTION ENVIRONMENTAL factors greatly influence production characteristics of chickens. The effect of varying temperatures on egg production traits of Leghorns in cages has not been investigated thoroughly. It is the purpose of this paper to report the results of such a study. The work was done at Agricultural Research Center of the U. S. Department of Agriculture. The study was cooperative with Animal and Poultry Husbandry and Agricultural Engineering Research Branches of the Agricultural Research Service. The senior author was on leave from the University of California. EXPERIMENTAL PROCEDURES AND EQUIPMENT S. C. White Leghorn pullets, hatched on March 8, 1954, were raised on the range until August 5, then brought indoors and placed in three-tiered 48-hen capacity commercial individual laying cages. Later on August 19, thirty pullets selected on the basis of maturity and egg production were used in the three groups. The ambient room temperature during the week . . .

THE results of experiments reported by Gallup and Norris (1939) constitute additional evidence that perosis in chicks is due to a deficiency of manganese. The results support the contention that the deficiency is of dietary origin intimately related to the manganese requirements of the breed under investigation. Perosis consistently occurred in about 4 percent of the chicks in several experimental groups which were allowed adequate amounts of manganese. Since these cases developed soon after hatching the possibility of impaired manganese utilization induced by factors, dietary or otherwise, which operated during embryonic development and early growth was indicated. Accordingly, a study has been made of the assimilation and storage of manganese in the developing embryo, and in chicks receiving diets of medium and low-manganese content. The present paper reports the results of this investigation. EXPERIMENTAL Eggs from a selected group of New Hampshire hens were incubated weekly. The hens received an . . .

INVESTIGATIONS on the ability of growing and laying chickens to tolerate cane final molasses have been reviewed by Ewing (1951) and Scott (1953). In general, as with young chicks, earlier reports have shown that the growing chicken can make effective use of levels ranging around 5 percent of total ration, whereas concentrations in excess of 10 percent tended to induce diarrhea and were uneconomical. Similarly, it was concluded that mature chickens cannot efficiently utilize comparatively high levels of molasses. In contrast, two papers have recently presented studies which tend to refute these earlier reports. It was found that optimum results to 6 weeks of age, as determined by growth rate and cost of feed per unit of gain, may be obtained on concentrations of cane final molasses ranging from 7.5 to 23.0 percent, while other lots of chicks safely tolerated levels as high as 34.5 percent of total ration (Rosenberg, 1955)… .

The experiments which are the subject of this paper were started in 1925. It was their original purpose to test whether embryonic malformations or disturbances of development of one or the other kind might be induced by exposing the embryos to electrolyte solutions during the first stages of development. Lippincott and de Puy had reported about experiments in which they incubated eggs lying in shallow distilled water up to the 18th day of incubation. Since the hatchability in these experiments was surprisingly high (28.57 to 47.22%), it appeared probable that a similar method but with Ringer’s physiological salt solution for a medium would yield still better results. Eggs, therefore, were placed in zinc pans coated with paraffin, and enough fluid was poured in to cover the lower half of the eggs. Once a day distilled water was added to compensate for loss by evaporation. The eggs were kept in these . . .

In a previous paper (Steggerda, ’28) it was shown that by the injury or partial removal of the ovary of fowls certain birds were stimulated to lay more eggs. This result appears to be related to the work of Zeleny (’03) on regeneration in Brittlestars, from which he concludes, “the greater the number of removed arms, (excepting the case where all are removed) the greater is the rate of regeneration of each arm,” and also to the work of Hartman (’25) on semispaying of the opossum in which he states, “ a compensatory hypertrophy was noted.” The work of Pearl (’21) on the partial removal of the ovary of fowls is also related; he concludes, “The total number of oocytes developing to visible size in the lifetime of a bird is caused to increase from 33 to 68 percent over the number which develope in the normal unoperated bird.”

INTRODUCTION UNDER floor housing a bird’s position in the peck order, and her aggressiveness are correlated with her egg production (Sanctuary, 1932; Guhl, 1953; McBride, 1958, 1964). This effect is most probably related to her ability to freely obtain food and water. McBride (1958) suggested that selection for egg production under floor housing would lead to an increase in relative aggressiveness. The experiments described in this paper were designed to determine whether the relative aggressiveness of two lines of White Leghorn poultry selected for increased part-record egg production under floor housing had changed relative to that in their unselected base population. MATERIALS AND METHODS The lines of White Leghorns used were S275, S% and O.C.S. (the Ottawa Control strain of Gowe et al., 1959). S275 originated in 1955 from a sample of O.C.S. and has been selected for number of eggs from housing (147 to 156 days of age) till…

SINCE the initial reports of Carlson et al. (1949), Menge et al. (1949) and Wiese et al. (1949) showing the need by the chick for an unidentified growth factor or factors, considerable effort has been directed toward the development and use of suitable chick assays. Much of this work has been reviewed by Menge et al. (1952), Branion and Hill (1953), Combs et al. (1954a), Lillie et al. (1953) and Pappenhagen et al. (1953). The observations reported in this paper were made in unidentified factor experiments conducted during a two-year period at this station. An effort has been made to determine some of the causes of variability encountered in our experimental assay. EXPERIMENTAL Day-old New Hampshire chicks of both sexes were employed in all experiments except experiment 6 in which New Hamp-shire × Silver Cornish crossbred males were used. 3 All New Hampshire chicks were the progeny of dams housed on …

INTRODUCTION POULTRY breeders are finding that laying cages are a useful aid in poultry breeding. Most breeders using cages are resorting to artificial insemination in order to reproduce their breeding stocks. Further information is needed concerning semen yields of males to facilitate the increased use of artificial insemination. The purpose of this paper is to report the results from a study on the yields of semen among inbred lines and crosses of S. C. White Leghorns. REVIEW OF LITERATURE Burrows and Titus (1939) observed that crossbred (B. P. Rocks×R. I. Reds) cockerels averaged over 1.0 cc. semen per bird per collection. They obtained a significant correlation between testes size and semen production. They concluded that 61 percent of the variation in semen production was due to differences in testes size. Wheeler and Andrews (1943) obtained results which indicate a seasonal variation in production of semen in Barred Plymouth Rock males… .

EGGS have long been used as a medium ingredient for promoting the growth of bacteria and protozoa, and have been used for tissue cultures. They have been highly recommended as the first solid food for infants and as a staple in the adult diet. It was rather disconcerting, therefore, to see a paper suggesting that eggs contained a carcinogen. Szepsenwol (1955 Szepsenwol (1958a) reported that female chicks fed a diet of whole hatchery waste eggs, autoclaved for 40 minutes at 20 lbs. pressure, mixed with wheat bran, iodized salt and cod liver oil (the latter for the first month only) came into production relatively early and males had large combs, wattles and spurs. Controls on Purina broiler mash were smaller and became productive 2 months later than those on the egg diet. Four New Hampshire females, but no controls, were kept on the egg diet for 28 months, while three White …

THIS paper presents a brief report on the effect of age on the egg production and hatching results of Bronze turkey females during the period 1927 and 1933 inclusive. Some data are also presented on the comparative mortality and rate of growth of the progeny. In compiling the data the age of the males to which the females were mated was disregarded. Egg Production All reports so far published, regarding the effect of age on egg production deal with the domestic fowl. Brody, Henderson, and Kempster (1923) reported that the egg production of the flock studied declined 12 percent each successive year. Jull (1928) and Hall and Marble (1931) have shown that the decline in egg production with age is greater in the case of the Barred Plymouth Rock, Rhode Island Red, and Wyandotte breeds than in the case of the White Leghorn. They as well as Atwood (1928) and . . .

IN A PREVIOUS paper (Byerly and Quinn, 1936) it was shown that 47.5 percent of 1,102 Rhode Island Red chicks hatched at the National Agricultural Research Center, Beltsville, Maryland, carried black spotting on the head or black striping on either head or body, also that 42.1 percent of 663 chicks from an excellent standard bred flock carried spotting or striping, indicating that these characteristics may be rather widely distributed among Rhode Island Red flocks. It was further shown that 84.9 percent of the striped or spotted Beltsville chicks were females, whereas 77.8 percent of the non-spotted, non-striped chicks were males. Several breeders and hatcherymen have questioned the extent of the distribution of the characteristics mentioned above. They have also pointed out that little melanic pigment (black spotting and striping) appears in the Rhode Island Red Chicks shown in commercial and standard bred exhibition classes. It was the opinion of the . . .

VITAMIN G is one of the important nutrients of properly prepared alfalfa leaf meal. The term vitamin G used in this paper pertains to the growth promoting factor and not to the B2 factor as described by Koehn and Elvehjem (1936). Bethke et al (1931) demonstrated the value of alfalfa leaf meal in preventing nutritional paralysis and promoting increased growth in chicks. Norris and co-workers (1934) reported that when alfalfa meal was fed to breeders as a supplement to a diet deficient in vitamin G, hatchability was improved. Hunt, Record, and Bethke (1935) showed with rats that alfalfa hay contained much more vitamin G than vitamin B and that the content of these vitamins decreased in amount as the plant matured. In general, the quantity of these vitamins present was correlated with leafness, greenness, and protein content of the plant. Wilgus, Norris, and Heuser (1936) showed that the average vitamin . . .

A FRESHLY laid egg has a white which is firm and stands up well. After the shell egg has been kept for a few days at room temperature or for a longer period in cold storage, the broken out egg white contains less firm white (Almquist and Lorenz, 1932; Lorenz and Almquist, 1936) and becomes less viscous and spreads out much more (Evans and Carver, 1942b; Evans, 1943). The whites of these older eggs do not stand up well and are considered to be of poorer quality (Wilhelm and Heiman, 1938; Evans and Carver, 1942a). Evidently some changes in the protein structure of the white must occur during storage of shell eggs, because egg white is composed primarily of water and protein. Evans and Bandemer (1956) developed a method for the separation of egg white proteins and their quantitative estimation by filter paper electrophoresis in order to make possible a . . .

EGG production of turkeys is not important commercially but good egg production during the breeding season is desirable in order to obtain a satisfactory number of poults per breeding female. To present information regarding the egg-laying ability and habits of turkeys is the purpose of this paper. The problem undertaken was to determine: (1) the average size of the egg laying clutches, (2) the extent to which Bronze turkey hens (under modern conditions of management) lay according to the “litter” theory, (3) the average number and length of the litters and of the pauses between them, (4) the average egg production up to the end of May of hens lighted and not lighted, (5) the effect of age on egg production occurring from commencement of laying to the end of May, and (6) the average annual egg production. Trapnest and flock egg records of Bronze turkeys obtained over a period . . .

SEVERAL reports have appeared which suggest that thyroprotein, (iodinated casein) may have beneficial effects when fed to young chicks and, during the summer months, to laying hens (Parker, 1943, Irwin, Reineke and Turner, 1943, Turner et al., 1945, Turner, Irwin and Reineke, 1945, Gutteridge and Pratt, 1946, Gutteridge and Novikoff, 1947, Wheeler, Hoffmann and Graham, 1948). No experimental data are available, however, on the effect of feeding thyroprotein during the “growing period,” but Turner (1947) has recommended in a popular article that, “For growing pullets, the . . . (thyroprotein) feeding can continue at the rate of 15–20 grams per hundred pounds of their total feed until the approach of sexual maturity. Then the . . . (thyroprotein) can be cut to 10 grams per hundred pounds of their total feed.” The present paper reports on the effects of feeding thyroprotein during the 12 weeks period (12 to 24 . . .

CONSIDERABLE effort has been expended in recent years to discover just what quality is in reference to the contents of an egg, to set up and to standardize ways of improving and maintaining it at a high level. But there has been little work to show differences in the initial quality of eggs, as determined by present day measures, that occur with season. Parker, Grossman and Lippincott (1926) concluded that there is no seasonal effect on the color of the yolks of eggs. Almquist (1933) states that, “eggs are not all ‘created equal’ or, if they are, they do not long remain so. Initial quality and keeping quality may vary greatly from egg to egg, but are found to vary to a relatively small extent in eggs from the same hen.” This paper considers the seasonal changes in the interior quality of eggs laid by a flock of S.C. White . . .