The influence of a diet containing Helminthosporium maydis blighted corn on laying hen performance.
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Animal Feed↗
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Fertility, hatchability and progeny performance of laying hens fed high levels of DDT in the diet.
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Adipose Tissue↗
Rapeseed meal glucosinolates: metabolism and effect on performance in laying hens.
Two experiments were conducted with Hyline Leghorn hens to study the metabolism and detrimental effects of rapeseed meal (RSM) glucosinolates. Raw Target RSM was force fed to 12 hens which were killed after varying time intervals (15 min., 30 min., 60 min.) and the contents of areas of the digestive tract (crop; proventriculus and gizzard; duodenum and ileum) were analyzed for the presence of hydrolysis products of progoitrin. Nitrile compounds were found to be present in all areas of the digestive tract in much larger relative amounts than was oxazolidinethione. When commercially prepared RSMs of varying glucosinolate content were fed to laying hens at a 50% level of dietary inclusion, high glucosinolate-content RSM depressed egg production (P less than 0.05) more than low glucosinolate-content RSM but did not cause a greater frequency of liver hemorrhage. Histological examination of liver tissues from hens suffering liver hemorrhage revealed a severe reticulolysis.
Animal Feed↗
Reproductive performance of laying hens fed tungsten.
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Animal Feed↗
Performance of laying hens subjected to intermittent lighting initiated at 24 weeks of age.
Leghorn pullets of a commercial strain were subjected to a conventional light program of constant photoperiod or an intermittent programming involving, during the house of conventional "lights-on", 45 min light (L): 15 min dark (D) from 24 to 27 weeks of age; 30 min L:30 min D from 28 to 35 weeks; and 14 min L:45 min D from 36 weeks to the duration of the trial. Each light treatment was tested with 12 replicate groups of 14 individually caged birds housed in adjacent rooms, with all birds fed a standard 15% crude protein, 2750 kcal ME/kg diet. Intermittent lighting resulted in a significant (P less than .05) reduction in feed intake and a consistent but nonsignificant (P less than .05) reduction in egg production. Egg size, egg shell quality, and albumen quality, as assessed by Haugh units, were not affected by light treatment. Due to the effect on egg production, it is concluded that intermittent lighting programs should not be initiated close to time of peak egg production.
Animals↗
Performance of laying turkeys grouped according to daily food intake.
The individual food intake of 120 Large White turkey hens in cages was measured for 3 weeks for 36 to 39 weeks of age. Based on that rate of intake, hens were divided into four treatment groups: two high intake (HI) and two low intake (LI). A control diet was fed to one HI group and one LI group. In addition, diets with different nutrient density were formulated for one HI group and one LI group. The experimental period was for 10 weeks beginning when the hens were 39 weeks of age. There were no significant differences among the groups for rate of egg production, total number of eggs, egg weight, or egg specific gravity, although there were significant differences for the daily intakes of protein, sulfur amino acids, lysine, phosphorus, calcium, and metabolizable energy. These data indicate that, at 39 weeks of age, there was no benefit from grouping birds based on previous food intake and feeding them diets to increase or decrease daily intake of certain nutrients.
Amino Acids, Sulfur↗
The effect of low protein pullet growing diets on performance of laying hens housed in the fall.
A total of 6000 layer-type pullet chicks were fed either a low protein (9.1%) or a high protein (15.4%) diet from 8 through 18 weeks of the growing period in two experiments. All chicks were fed a commercial starter for the first 8 weeks and the high protein diet from 18 to 21 weeks of age. All chicks were grown in floor pens and were supplied feed and water ad libitum throughout the growing trial. They were placed in either a cage- or floor-laying house and fed a commercial layer diet for 12 periods of 28 days each. The experiment was repeated in the subsequent year. The low protein regimen was found to produce a smaller pullet, delay sexual maturity, delay production peaks, and maintain higher levels of production near the end of the laying period. Pullets fed the low protein grower diet had higher mortality during the growing period, greater feed intake during the laying period, eggs with higher Haugh unit values, and reduced egg production in the laying house.
Animals↗
The performance of laying hens as affected by copper sulfate and methionine level.
Two strains of White Leghorn hens were subjected to seven copper treatments that included a negative control for the first week of each of five 28-day periods. The hens were approximately 500 days of age when the experiment began. Copper treatments were assigned to simulate the different levels of copper intake that might result from differences in daily feed intake similar to the practice followed with commercial industry. In order to simulate daily dietary intake ranging from a low of 73 to a high of 136 g per bird, levels of 76, 91, 100, 114, 129, and 143 mg of copper sulfate per kilogram were added to each of the basal diets. Treatments were administered across two methionine levels in a corn-soy basal diet. Hen-day egg production, egg weight, daily feed intake, and feed efficiency values were not affected by dietary levels of copper or methionine. Hens fed diets containing low methionine laid eggs with significantly poorer specific gravity.
Animals↗
The influence of dietary phosphorus level on laying hen performance, egg shell quality, and various blood parameters.
The influence of dietary phosphorus on hen performance and egg shell quality was investigated. Total dietary phosphorus levels of .17, .23, .30, .40, .50, .70, 1.50, and 2.30% were fed to four body weight groups of 23-week-old White Leghorn hens. Hens consuming the diets containing .17, .23, and .30% phosphorus, all from plant origin, consumed significantly (P less than or equal to .05) less feed, which resulted in poorer performance than hens fed diets supplemented with inorganic phosphorus. Addition of supplemental inorganic phosphorus at levels of .10 to .40% resulted in the best overall hen performance. Plasma phosphorus was directly related to dietary phosphorus level. Egg shell quality as measured by specific gravity was inversely related to dietary phosphorus levels above .50%.
Animals↗
Effect of a high-protein diet fed prior to the onset of lay on performance of broiler breeder pullets.
The influence of protein level (154 versus 181 g/kg) in a prelayer diet fed from 134 to 181 days of age on the subsequent performance of hens was studied with two strains of broiler breeders. Birds given the prelayer diet of 181 g protein/kg showed higher egg production, 110 versus 101 eggs per bird, and a lower requirement for amount of feed per egg. The differences were noted mainly in the period 35 to 50 weeks of age. No differences were observed in age at 50% production, egg weight, incidence of cracked eggs, hatchability, or mortality.
Animals↗
Virginiamycin and laying hen performance.
Two experiments were conducted for five 28-day periods each. In Experiments 1 and 2, Hyline W-36 hens, 36 and 26 weeks of age, respectively, were used. Experiment 1 was designed to measure the effect of virginiamycin on hen performance and egg characteristics when supplementing a diet having low pigmentation potential. In Experiment 2, the diet contained 3% added fat with 0, 10, and 20 ppm virginiamycin. In Experiment 1, virginiamycin-supplemented hens showed increased (P less than or equal to .05) egg production, body weight, and improved feed efficiency. When egg production and feed efficiency were ranked by quartiles within the control and virginiamycin-supplemented groups, virginiamycin was shown to benefit only the poorer producing hens. In Experiment 2, added fat improved feed efficiency; however, the response to virginiamycin, as observed in Experiment 1, did not occur.
Animals↗
Effects of comb dubbing on the performance of laying stocks.
Three studies were conducted with birds dubbed at hatch vs. dubbed and dewattled at 118 days or 255 to 260 days of age or with normal hens. In the first, involving 5928 pullets of four strains housed 1 per cage, dubbing and dewattling at 255 to 260 days caused small adverse effects on egg numbers as compared with nondubbed controls. Body size was reduced, and both egg weight (EW) and shell strength were increased slightly. In the second study, involving 8180 pullets of nine strains housed 1 per cage, dubbing and dewattling at 118 days slightly increased survivor egg production (SEP) and laying house mortality, and reduced age at first egg, 240-day EW, and 450-day Haugh units (HU), as compared with dubbing only at hatch. There were significant strain by dubbing treatment interactions for hen-day rate of lay (HDR) and SEP. In the third study, involving 1824 pullets of three strain crosses housed 2 and 3 birds per cage (three different cage sizes), there were no significant differences between birds dubbed at hatch and those not dubbed. Variation in age at 50% production, SEP, and HDR was reduced for the dubbed groups. These studies show that the older the birds are when dubbed, the greater the negative effects of dubbing. Hens dubbed at hatch exhibit no effects with the early dubbing or adverse effects in the laying house.
Animals↗
Fluorine toxicity and laying hen performance.
Two hundred eighty-eight Single Comb White Leghorn (SCWL) hens were treated for 252 days with sodium fluoride added to a practical wheat-soybean meal-type basal diet to supply 0, 100, 400, 700, 1,000, and 1,300 ppm fluoride (F). On Day 252, hens fed the two highest levels of F were switched to the control diet and the experiment continued for another 168 days. The two highest levels of fluoride resulted in significant (P less than .05) depression of feed intake, body weight gain, hen-day production, feed efficiency, and egg quality. Fluoride (700 ppm) tended to reduce performance but generally was not significantly different from the control and lower F diets. Long-term feeding of high levels of F (NaF) did not result in permanent production impairment. Birds fully recovered during the 168-day recovery period. In the second experiment 288 SCWL pullets were treated for 49 days with seven dietary regimens: 0 ppm F fed ad libitum (1), 1,300 ppm F fed ad libitum (2), 0 ppm F control pair-fed to 1,300 ppm F (5), an NaCl diet formulated to supply as much Cl- as F- in diet 3 (4), an NaCl diet formulated to supply as much Na as supplied by NaF in Diet 3, (5), 1,300 ppm F plus 1,040 ppm Al diet fed ad libitum (6), and the same diet pair-fed to the 1,300 ppm F diet (7). All groups were fed the control diet for a 7-day recovery period at the end of the experiment. High F intake significantly (P less than .01) decreased feed intake, hen-day production, feed efficiency, and shell quality. However, these depressions were not as severe when Al was present in the diet. The depression in performance due to F feeding was not simply due to the depressed feed intake but rather was a result of a metabolic function of F. Pair feeding the control and F/Al diets resulted in much smaller depression. Egg shell quality was more responsive to the addition of Na to the diet than the F. Although feed consumption recovered within the 7-day recovery period, this time was inadequate for complete recovery in egg production.
Animals↗
Influence of probucol ((4,4'-isopropylidine dithio)-bis(2,6-di-t-butyl-phenol)) on egg yolk cholesterol content and performance of laying hens.
Addition of the hypocholesteremic agent Probucol ((4,4'-isopropylidine dithio)-bis(2,6-di-t-butyl-phenol)) to the diet of laying hens at up to 1% significantly reduced egg yolk cholesterol content (mg/g yolk) without impairment of rate of egg production, egg weight, shell strength, albumen quality, or other production related parameters. Dietary concentration of .1% Probucol significantly reduced yolk cholesterol within 2 weeks after feeding. Higher concentrations did not further reduce yolk cholesterol. Probucol at .025% reduced egg yolk cholesterol within 4 weeks after feeding, but after 8 weeks of feeding, eggs from hens fed .025% Probucol did not differ significantly in yolk cholesterol from those fed the basal unsupplemented diet. This suggests possible adaptation in cholesterol synthesis by the laying hen.
Animals↗
Postmolt performance of laying hens molted by high dietary zinc, low dietary sodium, and fasting: egg production and eggshell quality.
Single Comb White Leghorn (SCWL) hens, 65 weeks of age, were assigned to one of four dietary treatments: fasting to a body weight loss of 34% (FAST), administration of a diet containing less than or equal to 500 ppm sodium for 42 days (Lo Na), administration of a diet containing 20,000 ppm zinc for 10 days (Hi Zn), and a control (CON) diet. The hens were subjected to two photoperiod treatments, those receiving 17 hr (17-hr) of light per day throughout the 32-week experiment and those restricted to 8 hr of light per day for the first 42 days followed by a .5 hr/day increase until 17 hr was reached. Egg production and mortality were recorded daily. Feed consumption, feed conversion, and livability were determined weekly. Beginning on Day 56, eggs were collected at 28-day intervals for determination of egg weight, egg specific gravity, and shell weight. During the molt phase (1 to 6 weeks), the 17-hr light day significantly increased egg production, feed consumption, and decreased feed conversion (kg/doz) across all groups when compared with the 8-hr light/day treatments, but FAST treatments consumed identical amounts under both light treatments. From 7 to 32 weeks during the postmolt phase, egg production was significantly increased and feed conversion decreased by the FAST and Hi Zn treatments relative to CON, Lo Na treatment was intermediate. Feed consumption was significantly higher for the FAST treatment. Overall, there were not significant effects on egg production, feed consumption, and feed conversion.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Effects of pullet-stocking density on performance of laying hens.
Effects of cage-stocking density during the rearing period on three commercial strains housed in open and closed rearing and laying houses were examined in two experiments. Stocking densities in Experiment 1 were 311, 259, and 239 cm2 per bird and in Experiment 2 were 311, 259, and 222 cm2 per bird. In the rearing period, greater stocking densities significantly reduced feed intake and 18-wk body weight and increased age at 50% production. In the second experiment, mortality to 20 wk was higher among birds reared at 222 cm2 per bird compared to the less dense treatments. In the laying phase of the experiments, there were no differences among the treatments in number of eggs per bird housed, layer mortality or kilograms of feed consumed per kilograms of egg produced. Final (499 days) body weight of hens reared at 222 cm2 per bird was significantly less than that of those in the other treatment groups. Egg weight of birds reared at 22 cm2 per bird was significantly greater than that of birds reared at 311 cm2 per bird in Experiment 2. Calculated incomes over feed and chick costs were not different among the treatments in either experiment. A less rapid decline in egg production was noted among birds reared at the highest stocking density over the time of the experiment.
Animal Husbandry↗
Influence of Fermacto on the performance of laying hens when fed diets with different levels of methionine.
An experiment was conducted to determine the effect on laying hens of adding Fermacto at a level of 454 g/909 kg diet to diets containing various levels of supplemental methionine. The addition of Fermacto to the basal diet resulted in increased (P less than or equal to .05) production, egg mass, and feed intake while improving feed efficiency. A significant (P less than or equal to .05) main effect for supplemental Fermacto over all levels of added methionine was found for egg production and feed efficiency.
Animal Nutritional Physiological Phenomena↗
Production performance of laying hens fed L-tryptophan.
The purpose of this study was to determine whether supplementing L-tryptophan to a nutritionally complete diet would influence egg production rate and egg shell quality in laying hens. One hundred and twenty layers (Rhode Island Red x White Leghorn) were randomly allocated into three groups. Birds were fed a basal diet or diets supplemented with L-tryptophan at 250 or 500 mg/kg for 405 days from 25 wk of age. Hen day egg production and daily egg output were proportionately higher with higher levels of supplemental dietary L-tryptophan; the differences were significant (P less than .05) for layers fed the 500 mg tryptophan/kg diet. The improvement in egg production by dietary L-tryptophan was greatest during the latter part of the laying period. These findings suggest that supplemental L-tryptophan improves the egg production rate in laying hens.
Animal Feed↗