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At least 19 recordsLinked to original sources
PubMed2006

Divergent selection on feather pecking behavior in laying hens has caused differences between lines in egg production, egg quality, and feed efficiency.

The correlated changes in egg production, egg quality, and feed efficiency (FE) due to selection for feather pecking (FP) were investigated by analyzing the data from an experiment including 2 divergently selected lines and a control line. The experiment was conducted with hens from 42 to 46 wk (hatch 1) and 39 to 43 wk (hatch 2) of age in the fifth generation of selection. The number of FP bouts per hour in the low FP line (LFP) was lower than the high FP line (HFP; 0.38 vs. 2.01), and total plumage score in line LFP was better than in line HFP (16.9 vs. 11.6). During the 4 wk, egg number and egg mass in line LFP were higher than those in HFP (24.4 vs. 18.3 and 1,223 vs. 1,132 g, respectively). On the other hand, line HFP had greater egg weight (60.7 vs. 59.2 g), albumen height (73.0 vs. 64.9 in Haugh units), shell thickness (38.1 vs. 37.0 mm), and yolk percentage (30.6 vs. 29.5%) than the LFP line. The control line was intermediate for those traits. The residual feed consumption (RFC) was highest in line HFP, lowest in line LFP, and intermediate in line C. Partial regressions of feed consumption (FC) on BW gain and egg mass were not significantly different among the 3 lines, whereas a significant difference in regression on metabolic BW (32.6 g/d in line LFP, 38.0 g/d in control line, and 43.4 g/d in line HFP) was observed. In addition, there was a negative regression of FC per day on plumage score (-1.73 g). The adjustment for plumage score accounted for 60% of the difference between regressions on metabolic BW in lines LFP and HFP. These results indicated that selection for FP has led to a change in egg production, egg quality, and FE. The better FE in line LFP resulted from a lower requirement for maintenance energy. The later was partly accounted for by a better plumage cover.

Animal Nutritional Physiological Phenomena↗
PubMed2002

Chromium supplementation can alleviate negative effects of heat stress on egg production, egg quality and some serum metabolites of laying Japanese quail.

This study was conducted to determine the effects of Cr (chromium picolinate, CrPic) supplementation at various levels (0, 200, 400, 800 or 1200 microg/kg of diet) on egg production, egg quality and serum concentrations of insulin, corticosterone and glucose in laying Japanese quail (Coturnix coturnix japanica) reared under conditions of heat stress (32.5 degrees C). Laying Japanese quail (n = 150; 45 d old) were divided into five groups of 30 birds. The quail were fed either a control diet containing 965 microg Cr/kg diet or the control diet supplemented with 200, 400, 800 or 1200 microg of Cr/kg diet. Increased supplemental chromium increased body weight (P = 0.05, linear), feed intake (P = 0.05, linear), egg production (P = 0.01, linear) and also improved feed efficiency (P = 0.01, linear). Increased supplemental chromium linearly increased egg weight (P = 0.01), eggshell thickness, egg specific gravity (P = 0.05) and Haugh unit (P = 0.01). Serum insulin concentration increased linearly (P = 0.01), whereas corticosterone and glucose concentration decreased linearly (P = 0.05) as dietary chromium increased. The best results were obtained with 1200 microg Cr/kg diet, and chromium supplementation at such a level can be considered to be protective management practice in a quail diet, reducing the negative effects of heat stress.

Animals↗
PubMed2002

Vitamin E supplementation can alleviate negative effects of heat stress on egg production, egg quality, digestibility of nutrients and egg yolk mineral concentrations of Japanese quails.

The aim of this study was to determine if the negative effects of high ambient temperature (34 degrees C) on egg production, egg quality, digestibility of nutrients, and mineral content of egg yolk could be alleviated by dietary vitamin E (dl-alpha-tocopheryl acetate) supplementation in laying Japanese quails (Coturnix coturnix japanica). Japanese quails (n=240; 7-week-old) were divided into eight groups, 30 birds per group. The quails were fed either a basal diet or the basal diet supplemented with either 125, 250 or 500 mg of dl-alpha-tocopheryl acetate/kg of diet. Birds were kept at 22 degrees C and 55% relative humidity (RH). At 14 weeks of age, the thermo-neutral (TN) group remained in the same temperature as at the beginning of the experiment, whereas the heat stress (HS) group was kept at an environment-controlled room at 34 degrees C and 44% RH for 3 weeks. Heat exposure decreased performance when basal diet was fed (P=0.001). With 250 and 500 mg/kg of diet, an increase in body weight (P=0.01), feed intake (P=0.01), egg production (P=0.001), and improvement in feed efficiency (P=0.01) was found with vitamin E supplementation in quails reared under heat stress conditions (HS). Similarly, egg weight (P=0.01), egg specific gravity (P=0.01), egg shell thickness (P=0.05) and Haugh unit (P=0.01) were positively influenced by vitamin E supplementation. Heat exposure decreased digestibility of dry matter (DM) (P=0.03), organic matter (OM) (P=0.05), crude protein (CP) (P=0.02), ether extract (EE) (P=0.05) and were elevated by supplemental vitamin E (P<or=0.02). Egg yolk concentrations of Zn, Fe, and Mn decreased under high environmental temperature and were increased to values of the control group (P=0.001) when dietary vitamin E was supplemented. No significant differences in any values were observed in TN groups. Results of the present study conclude that supplementation with 250mg alpha-tocopherol acetate/kg of diet can be considered to be protective management practice in a quail diet, reducing the negative effects of heat stress.

Animal Feed↗
PubMed2002

Effects of dietary chromium and zinc on egg production, egg quality, and some blood metabolites of laying hens reared under low ambient temperature.

This experiment was conducted to evaluate the effects of chromium (chromium picolinate, CrPic) and zinc (ZnSO4 x H2O) on egg production, egg quality, and serum insulin, corticosterone, glucose, cholesterol, and total protein concentrations of laying hens reared under a low ambient temperature (6.8 degrees C). One hundred twenty laying hens (Hy-Line; 32 wk old) were divided into 4 groups, 30 hens per group. The laying hens were fed the control diet (T1) or the control diet supplemented with either 400 microg of Cr/kg of diet (T2), 30 mg of Zn/kg of diet (T3), or 400 microg of Cr plus 30 mg of Zn/kg of diet (T4). Although the dry matter intake (DMI) was similar (p > 0.05) for all treatment groups, supplemental chromium and zinc either individually or together increased live-weight change, egg production, and improved feed efficiency (p < 0.05). However, no significant differences were observed between T4 and T2 or T3. Compared to T1, supplemental chromium and zinc increased egg weight, eggshell weight, eggshell thickness, egg specific gravity, and Haugh unit (p < 0.05) in T2, T3, and T4 groups, among which there was no significant difference. Serum insulin concentration increased (p < 0.05) and corticosterone concentration decreased (p < 0.05) with dietary chromium and zinc supplementation. Serum glucose and choles- terol concentrations decreased (p < 0.05) and protein concentrations increased (p < 0.001) with dietary chromium and zinc supplementation in all treatment groups. The results of this study indicated that either supplemental dietary chromium or zinc increased plasma insulin and decreased corticosterone concentrations and that had a positive effect on performance of laying hens under low ambient temperature.

Animals↗
PubMed2002

Effects of dietary chromium picolinate and ascorbic acid supplementation on egg production, egg quality and some serum metabolites of laying hens reared under a low ambient temperature (6 degrees C).

This experiment was conducted to evaluate the effects of chromium (chromium picolinate, Cr Pic) and vitamin C (L-ascorbic acid) supplementation on egg production and egg quality in laying hens (Hy-Line) kept at 18 degrees C (at thermo-neutral zone) or 6 degrees C (cold stress) in temperature-controlled rooms. One hundred and fifty laying hens (32 week-old) were divided into 5 groups, 30 hens per group. The laying hens kept at 6 degrees C temperature were fed either a basal diet (low temperature-basal diet, LTB group) or the basal diet supplemented with either 400 micrograms of Cr per kg diet (Cr group), 250 mg of L-ascorbic acid per kg diet (Vit C group) or 400 micrograms of Cr plus 250 mg of L-ascorbic acid per kg diet (Vit C + Cr group) while hens kept at 18 degrees C fed a basal diet (thermo-neutral-basal diet, TNB group). Performance and egg quality were significantly reduced in LTB group compared with TNB group. Supplemental chromium and vitamin C significantly increased live weight change, egg production, and improved feed efficiency in cold-stressed hens compared with group fed the basal diet at 6 degrees C brought up to the values of the group reared under thermoneutral conditions (18 degrees C). Egg production and egg weight were also greater in each supplemental group compared with the LTB group. Separately or as a combination, supplemental chromium and vitamin C increased serum insulin but decreased corticosterone, glucose and cholesterol concentrations. Results of the present study show that supplementing vitamin C and chromium, particularly as a combination, improved the performance of cold-stressed hens. Such a combination of supplement can offer a potential protective management practice in preventing cold stress-related losses in performance of laying hens.

Animals↗
PubMedDate not supplied

Egg production, egg weight, eggshell strength, and mortality in three strains of commercial layers vaccinated with F strain Mycoplasma gallisepticum.

Three strains of commercial leghorns vaccinated at 17 to 22 weeks of age with F strain Mycoplasma gallisepticum (MG) were maintained through 117 weeks of age. The three strains differed in both mortality and percent egg production per hen housed; however, the strains did not differ in egg weight (EW), eggshell strength (ESS), or percent daily egg production. Results of this study indicate EW and ESS for F strain MG-vaccinated hens follow patterns previously reported for uninfected layers. Further, mortality may account, in part, for differences in percent egg production per hen housed between strains of F strain MG-vaccinated hens.

Animals↗
PubMed2006

Effect of strain of layer and age at photostimulation on egg production, egg quality, and bone strength.

Bone strength in layers is a concern for economic reasons and animal welfare concerns. Bone characteristics were investigated in 3 strains of hens: Babcock B-300, a small-bodied commercial white-egg layer; ISA-Brown, a commercial brown-egg layer; and an unselected Brown Leghorn line (BL). After being reared together in a single pen with 8 h of light per day, hens were caged with 14 h of light per day. Half of the hens were caged at 18 wk of age and the other half at 20 wk of age, resulting in a 2-wk difference in the age at photostimulation. Body weights, egg production, feed efficiency, and egg quality were measured throughout production. At 15, 25, 50, and 74 wk of age, hens were euthanized for sampling of the radius and the humerus. Breaking strength of the radius and humerus was measured, and the area and density of trabecular (largely medullary bone) and cortical bone were measured using quantitative computed tomography. Egg production and feed conversion of ISA-Brown hens was as good as or better than that of Babcock B-300 hens, and both commercial strains had higher production than the BL. Photostimulation late delayed sexual maturity and improved albumen and shell characteristics but had only minor effects on egg production and did not affect the yolk weight. The delayed photostimulation resulting from caging 2 wk later affected the radius by increasing the area of the trabecular space at 50 wk of age and the density of the bone in the trabecular space at 74 wk of age. Breaking strength of the humerus at 25 wk of age was greater for the birds that were photostimulated late but was not different later in the trial. The humerus, but not the radius, of the BL had a greater breaking strength than that of the commercial strains, suggesting that selection has decreased humeral breaking strength.

Aging↗
PubMed1983

The relationship between body weight loss during an induced molt and postmolt egg production, egg weight, and shell quality in caged layers.

Two trials were conducted to determine the relationship between percent body weight loss (% BWL) during an induced molt and postmolt performance. The molt was induced by fasting and photoperiod manipulation. Four groups with 24, 27, 31, or 35% BWL (Trial 1) or 20, 25, 30, or 35% BWL (Trial 2) were utilized in each trial. Performance was evaluated on the basis of 24 weeks of egg production and determinations of egg weight (EW), specific gravity (SG), and shell weight (SW) conducted during Weeks 8 (Trial 2 only), 18, and 24 following the removal of feed. The 27 and 31% BWL groups of Trial 1 and the 30 and 35% BWL groups of Trial 2 produced significantly more eggs per hen housed than the remaining treatments in their respective trial. Differences in SG and SW at the end of the trial were most pronounced in Trial 1 where the 27 and 21% BWL groups exhibited significantly greater SG and SW at Week 24 than did the 24 or 35% BWL groups. No significant differences occurred for SG at Week 24 of Trial 2, but the 35% BWL group exhibited significantly improved SW when compared to the 25% BWL group with the remaining groups intermediate. The EW was greatest for the 31% BWL and least for the 35% BWL group at 24 weeks in Trial 1 but did not differ in Trial 2. It was concluded that a body weight loss of approximately 27 to 31% produced optimum postmolt performance.

Animals↗
PubMed1994

Natural history of Schistosoma mansoni infection in mice: egg production, egg passage in the feces, and contribution of host and parasite death to changes in worm numbers.

Mice, C57Bl/6N (B6) and BALB/cAnN (BALB), infected with Schistosoma mansoni were examined 8-26 weeks postinfection (PI) to estimate the fecundity of the worms and the contribution of death of worms and the death of heavily infected mice to the decrease in worm numbers in chronic infections. Portal worms were recovered by perfusion and the lungs were examined for parasites shunted from the portal circulation. Animals that died were more heavily infected than those that survived. Between eight and 12 weeks PI, this loss of worms resulted in a net decrease of approximately 19% of worm pairs in surviving BALB mice, but of only 4% in B6 mice. Loss of portal worms to the lungs after the eighth week of infection was 9-13% of portal worms in BALB mice and 3-4% in B6 mice. The estimated rates of egg production by S. mansoni decreased slightly with time in both strains of mice. At 12 and 20 weeks PI, tissue eggs per worm pair and eggs passed in the feces per worm pair often decreased as the intensity of infection increased. We do not consider the loss of worms in the murine host relevant to most infections in humans because of the high intensity of infection relative to body size in mice and the high frequency of severe portal obstruction in murine infections.

Animals↗
PubMed1981

The effect of sodium fluoride on egg production, egg quality, and bone strength of caged layers.

The development of bone fragility in caged layers is a major problem in the poultry industry. The incidence of bone breakage during the processing of spent hens substantially reduces the economic return from these birds. In two trials, a commercial strain of White Leghorn pullets was used. In each trial, one-day-old chicks were divided into two groups, wing banded, and placed in floor pens. The treated group received fluoridated water at levels up to 300 ppm. The control group of birds received only well water. At 20 weeks of age, birds from each group were transferred to one of two laying batteries. One battery of birds received fluoridated water (100 ppm F). The other served as a control and those birds received only well water. Production rate, egg weight, shell strength, shell thickness, and Haugh units were determined for each bird. At 45 weeks of age, the humeri and tibiae were removed, and bone strength, percentage of bone ash, and fluoride content were determined. Combined data from both trials showed that the fluoride treatment increased the breaking strength of humeri from 6.86 to 13.35 kg and that of tibiae from 6.61 to 13.10 kg. The fluoride treatment also significantly (P less than .01) increased the percentage of bone ash. Egg quality and rate of production were not reduced by the fluoride treatment.

Animal Feed↗
PubMed1984

The effect of cyclic and constant ambient temperatures on feed consumption, egg production, egg weight, and shell thickness of hens.

Groups of 18 hens, 230 days of age, were housed in each of three climatic chambers with light schedules of 14L:10D. One was maintained at a constant temperature of 23.9 C, the second was cycled between 15.6 and 37.7 C (mean, 26.7 C), and the third was cycled between 21.1 and 37.7 C (mean, 29.4 C). In Experiment 1, the high temperature peaked during the dark period at 0200 hr and in Experiment 2, the high temperature peak was at 1400 hr during the light period. The birds had free access to a commercial breeder feed in these two experiments. The results from three 2-week observation periods indicated no significant differences in percent hen-day production, grams of feed per gram of egg mass, or overall body weight change but feed intake per day, egg weight, and shell thickness were significantly reduced by mean temperatures of 26.7 and 29.4 C in cycling chambers. The pair-feeding of birds in the 23.9 C constant chamber compared with those in the cycling 29.4 C chamber resulted in production of significantly heavier eggs with thicker shells without significantly influencing any of the other parameters. The reductions in egg weight and shell thickness observed at cyclic temperatures were not simply a result of a reduction in nutrient intake at high temperatures but also the direct effect of heat stress on the hens. In the 23.9 C constant temperature chambers, a reduction in AME of the feed for the hens fed ad libitum was observed but not for hens pair-fed to hens in the 29.4 C cyclic chamber.

Animals↗
PubMed1985

Effects of early maturation of brown egg-type pullets, flock uniformity, layer protein level, and cage design on egg production, egg size, and egg quality.

Eight-week-old Harco Sex-Link pullets were assigned to four growing regimens. Feed was restricted to Group 1. The birds reached an average weight of 1.52 kg at 20 weeks of age and were then light stimulated. Group 2 received the same ration ad lib and reached an average weight of 1.64 kg at 16 weeks. At this age they were light stimulated. Birds in Groups 3 and 4 were separated into two weight classes at 8 weeks of age. Those below the median weight received an 18% protein grower ration and those above the median weight a 16% ration. Group 3 birds were grown similarly to Group 1; Group 4 birds were grown similarly to Group 2. At housing, each group was equally divided and given either a 17 or 19% protein layer ration. Two cage designs (standard and reverse) were used and each treatment combination was equally represented. Ad lib-fed, early-housed pullets reached 1.64 kg at 16 weeks of age, but they did not come into production until 19.4 weeks of age. Hen-day percent production (HDP) was significantly less than for the late-housed pullets. Feed per dozen eggs was not affected by the early housing, but early-housed pullets laid significantly smaller eggs and feed per gram egg was significantly increased. Hens in reverse cages on a 19% protein layer ration laid the largest eggs in weight and size. Although early housing had a detrimental effect on average egg weight, it appeared possible to manipulate egg weight and size distribution through a combination of cage design and layer protein. Birds grouped by body weight at 8 weeks had higher uniformity, but this trait was not correlated with egg numbers or size. Moreover, housing body weights were not significantly correlated with egg size, suggesting factors other than body weight were responsible for the smaller eggs from early-housed pullets.

Animals↗
PubMed2003

Genetic variation for egg production, egg quality and bone strength in selected and traditional breeds of laying fowl.

1. A multi-breed experiment was conducted with 25 commercial and traditional lines of laying fowl to determine the extent of between-breed genetic variation for adult body weight, sexual maturity, rate of lay, egg weight and egg composition to 55 weeks of age. The genetic variability for bone strength and eggshell strength was determined at 55 weeks of age and a comparison of commercially selected and traditional breeds was performed. 2. The proportion of the total variation that was associated with breed or line of origin was high (> 0.8) for body weight, sexual maturity and shell colour; moderately high (0.4 to 0.7) for rate of lay, early and late egg weight, weights of egg yolk, albumen and shell at 55 weeks; and low (< 0.4) for egg weight at 42 to 45 weeks, albumen quality and the number of egg inclusions. 3. There were no detectable differences between breed within category (traditional and commercial lines) for rate of lay, and estimates of breed variation for egg weight and egg components were substantially decreased within category compared with the overall analysis. 4. Commercial lines displayed earlier sexual maturity, greater rates and persistency of lay, and higher egg weights at earlier (32 to 35 weeks) and later (52 to 55 weeks) ages. At 55 weeks, the larger eggs from commercial birds contained more albumen of higher quality and paler yolks of similar weight to those from traditional breeds. The relative weight of the eggshell was similar in both categories. 5. There was considerable genetic variation between commercial lines for bone density and a moderate proportion of genetic variability for bone strength. Commercial lines had very weak bones compared with traditional lines but there was relatively little genetic variation for eggshell strength. The results suggest that eggshell quality is maintained in genetically selected lines at the expense of bone strength and bone radiographic density.

Animals↗
PubMedDate not supplied

The effects of 6/85 live Mycoplasma gallisepticum vaccine in commercial layer hens over a 43-week laying cycle on egg production, selected egg quality parameters, and egg size distribution when challenged before beginning of lay.

In each of two trials, 80 commercial leghorn-type pullets were separated into two treatments with four replicates of 10 chickens in each treatment. Forty pullets were designated as controls and received no inoculation, whereas the remaining 40 pullets received the 6/85 vaccine strain of Mycoplasma gallisepticum (MG) at 10 wk of age. Hen-day egg production, egg weight, eggshell strength, Haugh unit score, pimpling incidence, and blood/meat spot incidence were monitored and recorded weekly in each trial through an entire laying cycle of 43 wk. Further, eggs from all treatments were collected daily, Monday-Thursday, and individually weighed. No significant difference was observed between the treatments for 43-wk means for hen-day egg production, for any of the monitored egg or eggshell quality parameters, or for the number of extra large, large, medium, small, pee wee, or undergrade egg sizes. A significant (P < or = 0.05) difference was observed for the number of jumbo-sized eggs between the two treatments. Results of this study suggest that vaccination of commercial layer chickens at 10 wk of age with 6/85 strain MG does not detrimentally impact egg production, egg size distribution, or ovary/oviduct function as evidenced by selected egg parameters monitored in this study.

Animals↗
PubMed1997

Ahemeral lighting of turkey breeder hens. 1. Cycle length effects on egg production and egg characteristics.

A study was conducted to determine the effective range of light-dark cycle lengths for reproductive performance in turkey hens. The treatments consisted of seven different light-dark cycle lengths: 21, 23, 24, 26, 27, 28, and 30 h each with a 15-h photophase per cycle. Data were collected for BW, feed intake, livability, onset and rate of egg production, egg weight (EW), shell thickness, and weight of egg components. The results indicate that turkey hens can be induced to lay eggs with light-dark cycle lengths other than 24 h (ahemeral) with practical extremes being about 23 to 28 h. Egg production in the ahemeral treatments never significantly exceeded that occurring in the 24 h group and the percentage of floor eggs increased at cycle lengths greater than 26 h and at 21 h. Cycle lengths of 21 and 30 h provided the most extreme deviations in the quantity and quality of eggs from those obtained on a 24 h cycle length. Shell thickness increased consistently as cycle lengths increased from 23 to 30 h. Egg weight increased in a curvilinear manner as cycle lengths increased or decreased from 24 h. This increase was associated with increases in shell, yolk, and albumen weight; however, the contribution by each was inconsistent, varying by cycle length as well as time on treatment. It may be concluded that an effective practical range of light-dark cycles for turkeys is 23 to 28 h and that 28 h is a reasonable limit to maximize EW and shell thickness while minimizing a reduction in egg production.

Animals↗
PubMed1999

The effect of dietary wheat middlings and enzyme supplementation. 1. Late egg production efficiency, egg yields, and egg composition in two strains of Leghorn hens.

A study was conducted to test the effects of wheat middlings (WM) with and without enzyme (xylanase and protease) supplementation on late egg production (EP), egg yields, and egg composition in two strains of Leghorn hens (DeKalb Delta and Hisex White). Six diets were randomly assigned to 300 birds (150 birds per strain) from 42 to 60 wk of age. Diet 1 was a corn-soybean meal control, Diets 2 and 3 had 8 and 16% WM, respectively, Diet 4 had 8% WM with 0.1% enzyme, and Diets 5 and 6 had 16% WM with 0.1 and 0.2% enzyme, respectively. Each dietary treatment was replicated five times per strain. Egg production, feed consumption (FC), feed efficiency (FE), percentage dirty eggs, specific gravity (SP), egg weight (EW), and egg mass (EM) were measured on a weekly basis. Egg components (EC) were measured biweekly and birds were weighed every 4 wk. Egg production was not significantly affected by diet, with averages of 83.7, 85.7, 84.1, 84.2, 82.3, and 84.0% for Diets, 1, 2, 3, 4, 5, and 6, respectively. Strain had a marked effect on FC, with Hisex having higher FC than DeKalb hens. Feed consumption also showed a significant diet by strain effect, being lower for Hisex hens fed diets with enzyme compared to diets without enzyme. DeKalb hens had better FE than Hisex hens, and addition of enzyme to 16% WM improved it further. Strain and diet had a significant effect on EC with higher percentages of albumen and yolk for diets with enzyme and for DeKalb hens. Percentage shell was lower for DeKalb hens than for Hisex hens but was not affected by diet. There was also a significant increase in EW for Diets 4 (63.1 g), 5 (63.8 g), and 6 (63.2 g) compared to Diets 1 (62.1 g), 2 (62.4 g), and 3 (63.0 g), with DeKalb hens showing an increase with Diet 5 compared to Hisex hens. Egg mass improved with the higher rate of enzyme in 16% WM diet compared to the lower enzyme level. Specific gravity declined with enzyme supplementation in WM diets. Eggs from DeKalb hens had lower SP than those from Hisex hens for all diets. Percentage dirty eggs did not differ significantly among treatments but was higher for the Hisex strain than for the DeKalb strain. There were no differences in BW between the two strains of hens or among diets. Adding protease and xylanase to diets rich in fiber can improve the egg output without affecting production parameters.

Animal Husbandry↗