Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “laying performance”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8Linked to original sources
PubMed1991

Research note: effect of excess lysine, methionine, threonine, or tryptophan on production performance of laying hens.

An experiment was conducted with laying hens to determine effects of feeding excesses of several individual amino acids in a practical layer diet. Single Comb White Leghorn hens, which were in peak production (31 wk of age), were assigned to one of five dietary treatments: a 16% CP corn and soybean meal positive control diet, or this diet fortified with 1% additional L-Lys, 1% additional DL-Met, 1% additional L-Thr, or 1% additional L-Trp. The diets were fed for ad libitum intake for 4 consecutive wk of production. For the entire production period, hen-day egg production, egg yield, and feed intake were not significantly different among any of the treatments. The study indicated that considerable tolerance exists in high-producing laying hens for individual excesses of the amino acids commonly used as supplements in poultry diets.

Analysis of Variance↗
PubMed1992

Laying hen performance as affected by diet and caging density.

Two trials were conducted to investigate the effects of caging density and diet on the performance of caged layers. Diets were formulated contain .775, .725, and .675% lysine. The TSAA content was formulated to be 85% of the lysine content of each diet. Pullets were caged in 25.4 cm wide x 40.0 cm deep cages at three, two, or one bird per cage. Production data were collected for 112 days in Trial 1 and 168 days in Trial 2. As dietary protein, lysine, and TSAA increased, hen-day egg production, egg weight, and feed conversion improved (P less than .05) . Feed consumption and feed per dozen eggs were not consistently affected by diet. Caging density had no consistent effects on any of the production parameters. No interactions were detected between dietary treatments and cage density in either trial.

Amino Acids↗
PubMed1993

Evaluation of two novel biochemicals on plasma and egg yolk lipid composition and laying hen performance.

PD132301-2, an inhibitor of acyl-coenzyme A:cholesterol O-acyltransferase (ACAT; EC 2.3.1.26), and 1-stearylboronic acid (SBA), a fatty acid analogue, were orally administered to White Leghorn hens in separate experiments to evaluate their effects on layer performance and plasma and egg yolk lipids. Five 60-wk-old hens each were fed either a corn-soybean meal basal layer ration, or the basal diet supplemented with .0121, .0363, or .1089% PD132301-2. In a second experiment, 12 37-wk-old hens each were fed either a basal layer ration, or the basal diet supplemented with .20 or .40% SBA. The duration of the experiments were 21 and 16 days, respectively. Neither compound significantly affected hen-day production, egg weight, yolk weight, BW gain, feed consumption, feed efficiency, plasma total cholesterol and triglyceride concentrations, or egg yolk cholesterol content. PD132301-2 had no effect on yolk fatty acid profiles, and C22:6n3 was the only fatty acid altered by SBA. Although 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors have been successful in reducing egg cholesterol, ACAT inhibitors and fatty acid analogues apparently hold little promise in this regard. The results of the present work also support the concept that, in order to pharmacologically alter the cholesterol content of eggs, direct inhibition of key enzymes in the cholesterol biosynthetic pathway is necessary.

Administration, Oral↗
PubMed1996

The effect of phenyl mercury on reproductive performance in laying hens.

The effect of phenyl mercury with and without selenium on the egg production of laying hens and on the fertility, hatchability and properties of eggs was studied. Mercury was administered via the feed at dosages of 5 ppm, 30 ppm, and 30 ppm Hg + 4 ppm Se, for 56 days. After two months, egg production decreased by 8.18% and 7.74% in hens fed 30 ppm Hg, and 30 ppm Hg + 4 ppm Se, respectively. Egg weight decreased in all experimental groups. In comparison to the controls, these results were highly significant (P < 0.01) in hens fed 30 ppm Hg and 30 ppm Hg + 4 ppm Se and significant (P < 0.05) between hens fed 5 ppm Hg and 30 ppm Hg. Fertility rate and hatchability were not affected. Mercury exposure did not affect egg shape, egg-white height, egg-shell hardness or yolk colour. Both egg-shell thickness and weight decreased in all experimental groups. In the group supplemented with selenium there was a nonsignificant improvement in egg production, hatchability and all qualitative properties of eggs in comparison with the group without selenium supplementation. Residual mercury levels in egg yolk greatly surpassed the level found in the egg white: the highest values were measured in the group fed 30 ppm Hg. The addition of selenium had a protective effect upon residual Hg deposits in the yolk, but not in the egg-white.

Administration, Oral↗
PubMed1993

Influence of prelay treatment and dietary protein level on the reproductive performance of White Leghorn hens.

Two experiments were undertaken to study the influence of prelay diet treatment on subsequent laying performance. Feeding either a conventional laying or growing diet or diets containing essentially only wheat bran from 18 to 21 wk resulted in little grower diet carryover effect beyond 24 wk of age, although the wheat bran diets resulted in a marked drop in body weight of the pullets during the prelay treatment. Similar performance was noted for pullets in a second experiment in which prelay treatments consisted of feeding just corn or wheat bran from 18 to 20 wk of age. In interpreting the results of the present study, it is important to consider the fact that "mature pullet weights" were obtained before the prelay diet treatments were employed. Where prelay diet treatments have had significant effects on laying house performance, in most cases, immature or underweight pullets were involved. Feeding hens low-protein diets (13 versus 17%) from 20 to 44 wk of age resulted in similar egg production; however, egg weight and thus egg mass were slightly reduced with the lower protein diet. There was no laying by growing treatment interaction. The importance of good pullet weight at the start of the production cycle and the subsequent performance of such pullets fed low-protein diets is discussed.

Animal Feed↗
PubMed1985

An economic analysis of performance data from toe-clipped laying hens housed at variable stocking densities.

Data from a previously reported study investigating the interaction of toe-clipping and stocking density on laying-hen performance were subjected to economic analyses to determine optimal profit-producing combinations of these two management practices. In three separate trials, toe-clipped (TC) and intact (IN) pullets were examined at caging densities of either 4 (465 cm2/hen) or 5 (372 cm2/hen) birds per cage. In each trial, beginning at 22 wk of age, hen production performance (hen-day egg production, hen-housed egg production, feed consumption, body weight, and mortality) was assessed for 12 28-day periods of lay. Performance criteria were averaged over all trials and used to determine per cage returns ($) above feed and pullet rearing costs (irrespective of fixed costs) and per cage profits (gross returns minus total costs) for the four treatment combinations. Economic analyses were also adjusted for hatchery toe-clipping costs. Profits (or losses) from each toe treatment stocking-density combination were calculated under variable egg and feed prices. At a blended egg price of $.35/doz, all cage systems lost money. Housing hen TC, 5/cage, yielded the greatest profits or least losses in 76% of the toe treatment stocking-density combinations studied. Economic returns were greatest for TC hens, 5/cage, at an egg price of $.55/doz when feed costs ranged from $140 to $230/ton and at egg prices higher than $.55/doz, regardless of feed prices. However, when these price combinations exist, housing hens IN, 4/cage is more profitable than housing hens TC, 4/cage.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Husbandry↗
PubMed2001

Effect of supplementary choline on the performance of broiler breeders fed on different energy sources.

1. Laying performance, egg quality, fertility and hatchability, and fat deposition in liver and abdomen were recorded in broiler breeders (29 to 48 weeks of age) fed on diets containing perarl millet (Pennisetum typhoides) (PM), broken rice (BR) or yellow maize (YM) (600 g/kg diet). Constant ratios of metabolisable energy (ME) to other nutrients were maintained in all the diets. Food grade choline chloride (50%) was added to the diets at 3 concentrations (0, 760 and 1,520 mg/kg). Each diet was offered to 3 replicate groups of 15 birds (12 hens and 3 cockerels), maintained in deep litter pens, to provide 1.46 MJ ME/bird/d. 2. Neither the source of energy nor dietary choline content had any influence on hen-d egg production, fertility or hatchability. Food efficiency and egg weight were significantly reduced in BR-fed groups compared to those fed on the other energy sources. 3. The efficiency of energy and protein utilisation increased and liver fat content was decreased significantly by dietary choline supplementation. 4. Haugh unit score, egg shell weight, liver weight and intestinal weight were not influenced by either supplementary choline or the source of energy. However, the yolk colour index was significantly reduced in PM- or BR-fed groups compared to those fed on the maize-based diet. 5. Deposition of abdominal fat was significantly greater in BR-fed birds compared to those fed on the YM-based diet, while liver fat content was significantly greater in the birds fed on the PM-or BR-based diets than those based on YM. Although supplementation of the diet with choline had no influence on abdominal fat deposition, liver fat content was significantly reduced in birds given diet containing 760 mg supplemental choline/kg diet. 6. The present study indicates that PM or BR can be used as principal energy sources in place of YM in broiler breeder diets without affecting egg production, fertility or hatchability. Liver fat content can be reduced by adding choline at 760 mg/kg to diets based on different energy sources.

Abdomen↗
PubMed1999

Production and egg quality as influenced by mash or crumbled diets fed to laying hens in an aviary system.

Effects of feeding a crumbled diet compared with a mash diet on laying performance and egg quality of two hybrids of laying hens, a total of 3,204 birds, kept in an aviary system from 20 to 80 wk of age, were investigated. The two diets had the same composition and calculated nutrient content. Two hybrids, Lohmann Selected Leghorn (LSL) and SLU-1329 (a two-line cross of Leghorn x Rhode Island Red), were housed in six pens each of an aviary system with groups of 269 and 265 birds, respectively. There was a total of three replicates per treatment (diet x hybrid). Birds fed the mash diet compared with those fed the crumbled diet had a significantly higher proportion of misplaced eggs, inferior feed conversion ratio (FCR), and higher energy consumption per kilogram egg mass produced (collectable misplaced eggs included). The latter birds had higher body and egg weight, suggesting a higher nutritive value for the crumbled diet. Higher egg mass production and a more intensive yolk color were also found for the birds fed the crumbled diet compared with the mash diet. Hybrid affected production and egg quality traits the most. The LSL also showed significantly higher excreta DM compared with SLU-1329. Interactions between diets and hybrids were found regarding the proportion of misplaced eggs, dirty eggs, egg weight, and FCR. Some of the interactions may indicate other genetic and nutritional factors affecting bird performance in aviary systems more than is normally seen in cages.

Animal Feed↗
PubMed1989

Effect of plumage renewal after induced moulting on subsequent laying efficiency and persistence.

1. Brown egg layers and dwarf broiler breeder females were force-moulted by different diets. The relationship between the extent of feather replacement and subsequent laying performance was studied. Some brown hens were subjected to metabolic experiments in order to compare post-moult heat production in relation to moulting success. 2. The extent of moulting had a clear effect on the post-moult heat production, and the differences were still present after 6 months in the second year of laying. 3. The extent of feather renewal during moulting showed high and very significant rank correlations with efficiency of food utilisation during the subsequent laying cycle. These correlations were generally higher than those of other features of the moulting procedure (body-weight-loss, minimum weight, duration of pause in laying). 4. The long-term energetic implications of the extent of moulting play an important role in subsequent performances and the persistence of lay during the following year is related to the extent of feather replacement.

Animals↗
PubMed2000

[A new live Salmonella enteritidis vaccine for chickens--experimental evidence of its safety and efficacy].

Within the works for the registration of a new live Salmonella Enteritidis vaccine for layers, safety and efficacy of the vaccine strain were tested by experimental studies. After oral administration of the single and the tenfold dose, no incompatibility reactions were seen in day-old chicks. The laying performance and the egg weight were not affected by the vaccination of the chickens during the laying period. There was only a limited period in which the excretion of the vaccine strain and its persistency in organs were seen. Even after the threefold oral vaccination the vaccine strain could not be isolated from eggs and internal organs of slaughtered chickens. Moreover, a high safety for non-target animals (cattle, pigs) could be established. Studies with BALB/c mice proved that a cell-mediated immunity and the development of complement-fixing antibodies is induced by the vaccine. Efficacy studies in target animals were carried out by a proved dependable oral challenge system that reproduces a latent infection with marked S. Enteritidis strains and by means of the seeder-bird method. The test results demonstrate that the vaccination is capable to avert or to reduce an infection significantly.

Animals↗
PubMed2000

Incorporation of different polyunsaturated fatty acids into eggs.

An experiment was carried out to examine thoroughly the relationships among different n-3 and n-6 polyunsaturated fatty acids (PUFA) in the diet, their deposition into the eggs' fat, and their effect on hens' laying performance. A diet enriched with 4% fish oil (FO) was fed to the birds throughout the 14-wk laying period (Treatment 1; T1); this was the same oil source that was replaced in proportions of 25, 50, 75, or 100% with four different fat sources, resulting in 17 isocaloric dietary treatments: linseed oil (LO; T2 to T5), rapeseed oil (RO; T6 to T9), sunflower oil (SO; T10 to T13), and tallow (T; T14 to T17). Performance parameters were recorded weekly and analyzed on the basis of the replacing fat source. At the end of the 14-wk experimental period, eggs were collected, and their fatty acid (FA) profile was determined. Performance parameters were not significantly different among grouped treatments. Smaller proportions of FO in diets resulted in lower values of saturated and higher values of n-6 FA contents, regardless of the fat source used when replacing FO. The n-6 content increased mostly because of the rise in linoleic acid (LA), although the level of arachidonic acid (AA) was always higher when FO was completely suppressed. The amount of the different n-3 long-chain PUFA was lower (P < 0.001) when FO was present in lesser proportions in the diet. However, the slope of the decline of these FA changed according to the included fat. Replacing FO with LO resulted in the lowest decline of its derivatives by elongation and desaturation and an increase in the total n-3 FA in the form of linolenic acid (LNA).

Animals↗
PubMed1997

Effects of environmental and social factors on incubation behavior, endocrinological parameters, and production traits in turkey hens (Meleagris gallopavo).

Hens raised in three different environments were assessed for changes in egg production performance, the rate of incubation behavior expression, and plasma levels of luteinizing hormone (LH) and prolactin for 20 wk following the laying of the first egg. The environments were individual (IFP) or collective floor pens (CFP) and individual battery cages (Cp and Cnp). The hens from three experimental groups (IFP, CFP, and Cp) were transferred from a short (6 h) to a long (14 h) photoperiod, whereas the ones from the remnant (Cnp) were left under a short one. Increase of the photoperiod induced significant increases (P < 0.05) in levels of prolactin and LH after 1 d, and resulted in the onset of egg laying in a delay of 14 d in all groups. However, the overall egg laying performance was highest for the IFP hens. The CFP and IFP hens laid 98 and 24% of their eggs inside the nest boxes, respectively. The hens raised in battery cages did not express incubation behavior, whereas 50 and 33%, respectively, of the CFP and IFP hens did. During the 1st wk of egg laying, levels of prolactin increased for all photostimulated hens but to a greater extent for CFP hens. Higher increases in levels of prolactin were associated with the expression of incubation behavior; however, prolactin levels of nonincubating laying hens were also higher under the CFP treatment. It appears that the rate of expression of incubation behavior, as well as changes in the plasma levels of prolactin and LH throughout an egg production period, are dependent upon rearing conditions in turkey hens.

Analysis of Variance↗
PubMed1991

Effects of dietary cottonseed meal and iron-treated cottonseed meal in different laying hen genotypes.

The effects of dietary screw-pressed cottonseed meal (CSM) and iron-treated CSM on laying performance and discolourations in eggs were examined in a range of hen genotypes. In experiment 1, six genotypes, obtained at point-of-lay from various sources, were fed on a non-CSM diet, a diet with 300 g CSM/kg, and a diet containing iron-treated CSM at 300 g/kg. In experiment 2, two of these genotypes were reared together from day-old and were fed from 10 to 18 weeks on a non-CSM diet or a diet containing iron-treated CSM at 250 g/kg. They were then fed on a non-CSM layer diet or a diet containing iron-treated CSM at 300 g/kg, in a 2 x 2 x 2 factorial design that also examined the effects of the rearing diet. 2. The effects on food intakes and egg production of including CSM and iron-treated CSM in layer diets depended on the genotype of the hens. The strongest interaction between breed and diet was on food intake, the breed Hubbard Golden Comet (HGC) being the least tolerant of CSM and iron-treated CSM. 3. Inclusion of iron-treated CSM in the rearer diet to supply approximately 70% of the dietary protein had no adverse effects on growth or age at first egg. Food intake and egg production between 18 and 26 weeks were affected by the iron-treated CSM layer diet, but there were no carry-over effects attributable to the rearing diets. 4. Genotype was not a factor in the development of the gossypol-related brown yolk discolouration in fresh or warm-stored eggs of hens fed on a CSM-based diet containing 197 mg free gossypol/kg and 52 mg cyclopropenoid fatty acids (CPFA)/kg (experiment 1). 5. In both experiments, the susceptibility of eggs to the CPFA-related cold storage effects depended on the genotype of the hen, eggs from hens of the HCG breed being more affected than those of ISA hens. 6. Treatment of CSM with crystalline ferrous sulphate heptahydrate, at a 4:1 weight ratio of iron to free gossypol, prevented brown yolk discolourations in all genotypes tested, as assessed by subjecting egg yolks to atmospheres of ammonia, and cold storage of eggs.

Ammonia↗
PubMed1984

Effect of heat stress and diet composition on performance of White Leghorn hens.

A total of 192 Single Comb White Leghorn pullets were divided into three groups to study the effect of heat stress and diet composition on feed intake and laying performance at 21, 25, and 33 weeks of age. For each age group all birds were fed a control diet [17.1% crude protein (CP), 2770 kcal metabolizable energy (ME)/kg] for a 7-day period. During this time they were kept at a temperature of 18 C. The temperature was then immediately increased to 35 C, and groups of 16 birds offered either the control diet, a high protein diet (43.5% CP), a high energy diet (3371 kcal ME/kg), or a diet of high nutrient density (28.3% CP, 2842 kcal ME/kg, and 6.5% Ca) for a 3-day period. After the 3-day test period, temperature was returned to 18 C, although birds were still offered the experimental diets for an additional 4 days prior to returning to the control diet. Production parameters were measured for individual birds. Feed consumption, egg production (except for the 21-week-old birds), egg weight, and egg shell thickness decreased (P less than .05) with heat stress. Increases in energy and calcium intake helped partially to maintain normal egg production, egg weight, and egg shell deformation. Egg weight and egg shell deformation returned to pretest levels within an 8-week postexperimental period. With the exception of those birds receiving the control and high nutrient density diets at 21 weeks of age, data collected over the test periods showed that heat stress caused a significant reduction (P less than .05) in liveweight birds.

Animals↗
PubMed1984

Lack of influence of pullet rearing conditions on the hen's performance.

The influence of three aspects of the rearing conditions of pullets on their performance as adults was investigated. The rearing conditions investigated were early acquaintance between birds, group size and stocking density. The production characteristics measured were laying performance, feathering and foot condition. No significant effect of rearing condition on the characteristics measured was found.

Animal Husbandry↗
PubMed2000

Effect of age of release from light or food restriction on age at sexual maturity and egg production of laying pullets.

1. Lohmann Brown pullets, in one trial, and Hyline Brown pullets in another, were reared from day 2 on short daylengths, and from week 8 in trial 1 (week 16 in trial 2) on food restriction. These restrictions were lifted at various times during the rearing period as a means of determining the relative importance of the day length and food restriction stimuli on the attainment of sexual maturity and subsequent laying performance. 2. A total of 2304 pullets were used in each trial. The birds were reared in light proof rooms, and subjected to 8L:16D until they were moved to a laying facility where a light stimulus of 16L:8D was applied. In trial 1 the six ages at which light stimulation was applied were 115, 122, 129, 136, 143 and 171 d. Within each light treatment, food restriction of pullets, which consisted of feeding 72 g of food/bird d, was lifted at six different ages, namely, 115, 129, 143, 157, 171 and 185 d. In trial 2 both the light stimulation and the lifting of food restriction occured at 111, 125, 139, 153, 167 and 181 d of age, producing 6x6=36 treatments in both trials. 3. The first trial was terminated when the pullets were 28 weeks old, soon after all the birds had commenced laying, because of an outbreak of Egg Drop Syndrome. However, because age at maturity was the variable of major interest, data from this experiment could be used in the analysis. The second trial ended when the birds reached 40 weeks of age. Variables measured were age at maturity, food intake and body weight gain subsequent to the lifting of restrictions and, in the second experiment, rate of lay, peak rate of lay and egg weight at various ages. 4. The mean age at sexual maturity was influenced by the date of release from light restriction (P<0.001) and from food restriction (P<0.001) in both trials. In addition, the interaction between the age at release from light and from food restriction was significant. Regression equations were produced for each trial to describe the relationships between the age at sexual maturity and the age at release from light restriction and food restriction. 5. There was an effect of both light restriction (P<0.001) and of food restriction (P<0.001) on the increase in food intake (g/bird d) in the week following release from food restriction in both experiments. These effects were not independent: the effect of the interaction of light and food restriction on this increase in food intake was also highly significant. The longer the birds were subjected to light restriction, the less dramatic the increase in food intake when food restriction was lifted. The more sustained the period of food restriction, the higher the increase in food intake in the week following release from the restriction. 6. Mean egg weight was 4 g heavier at 22 weeks of age in birds released from food restriction at 16 and 18 weeks, than from those released at 24 and 26 weeks of age. However, by 30 weeks of age, birds restricted for longer produced heavier eggs than their earlier-maturing counterparts. This effect continued to the end of the trial at 40 weeks of age, at which time there was a 2.3 g difference in egg weight between these treatments. 7. Both light and food restriction have an effect on the age of maturity in laying hens. The length of time between the release from light or from food restriction to the onset of laying depended on the age of the pullets when the release occurred. Egg weight at a given age was significantly affected by the age at release from food restriction, but not from light restriction.

Age Factors↗
PubMed1995

Effect of substituting sesame meal for soybean meal on layer and broiler performance.

Sesame meal (SM, 47.1% CP) has an amino acid composition similar to that of soybean meal (SBM, 47.7% CP) with the exception of lower lysine and higher methionine, but has been relatively underutilized in poultry feeds. Two experiments (1 and 2) were conducted to measure laying performance and hatchability of White Leghorn hens fed practical diets (17% CP), and two additional experiments (3 and 4) examined the performance of broiler chicks fed practical diets (22% CP) with varying substitution levels of screw-pressed SM for solvent-extracted SBM. In Experiment 1, SM contributed 0, 12.6, 25.3, 38, or 50.6% of dietary CP, and each diet was fed to hens for 6 wk. In Experiment 2, SM contributed 0, 4.7, 9.4, 14.1, 18.8, or 23.6% of dietary CP, and each diet was fed for 4 wk. In Experiment 3, SM contributed 0, 15, 30, 45, or 60% of dietary CP, and in Experiment 4, SM contributed 0, 38, or 76% of dietary CP; in these experiments, diets were fed to broiler chicks for 3 wk. There were no differences in egg production, egg weight, egg mass, daily feed intake, or body weight measurements among control hens fed SBM and hens fed SM at 12.6% (Experiment 1) or 4.7 to 18.8% of dietary CP (Experiment 2). Hens consuming these diets were able to satisfy their daily requirements for essential amino acids. Egg quality measurements were similar among hens fed the control SBM diet and those fed SM at 12.6 or 25.3% of dietary CP in Experiment 1, and at 4.7 to 23.6% of dietary CP in Experiment 2. All production variables were significantly depressed in hens that were fed SM at 38 or 50.6% of dietary CP, but Haugh units increased. In Experiment 3, the performance of broiler chicks fed the diet containing SM at 15% of dietary CP was not different from that of the control chicks fed the SBM diet, and both diets contained essential amino acids at required levels. Feed intake, body weight gain, and feed conversion were consistently depressed with increased SM substitution at 30, 45, or 60% of dietary CP. In Experiment 4, feed intake was not different between the control chicks fed the SBM diet and those fed the diet containing SM at 38% of dietary CP. However, body weight gain and feed conversion of chicks fed diets containing SM at 38 or 76% of dietary CP were significantly lower than those of the control chicks fed the SBM diet.

Animal Feed↗