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The influence of feed restriction during rearing was investigated in male-line Large White breeder hens with regard to effects on ovarian morphology, egg production, laying patterns, and egg characteristics. Two hundred poults were reared from 4 to 28 wk of age under four treatments as follows: full-fed controls (FF), low-protein diet (12% CP from 12 to 28 wk; LP), and reduced BW (10 to 20% lower BW than FF; R10 and R20). At photostimulation (28 wk), all birds consumed a commercial breeder diet ad libitum for the remainder of the study (48 wk of age). Settable egg production (eggs per hen) to 48 wk for all hens, and those in lay was: FF, 39.4 (48.6); LP 42.7 (51.7); R10, 41.4 (52.8); R20, 40.7 (55.4). Inferior egg production per bird in R10 and R20 hens reflected a reduced persistency of lay. At first egg, hens of all treatments had a mean of 4.9 postovulatory follicles (POF) not accounted for by an egg. Number of unreconciled POF correlated with abdominal fat pad weight (P < or = .01). Ovary weight correlated with BW (P < .0001) and fat pad weight (P < .0004). Proportion of yolk and shell in the egg and egg specific gravity were improved with feed restriction. Sequence length was longest in R20 treatment hens and pause length shortest in R10 and R20 hens. Incidence of multiple-follicle sets was reduced in the R10 and R20 treatments. Feed restriction during rearing can potentially improve laying characteristics by altering ovarian morphology without limiting shell quality or yolk size. Quantitative feed restriction was most effective at improving egg quality, reducing average pause length, and reducing ovarian multiple-follicle sets. If problems with persistency of lay are addressed, the R10 and R20 treatments are the recommended rearing restriction treatments for male-line turkey breeder hen candidates.

The influence of feed allowance during rearing was investigated in male-line Large White breeder hens. A flock of 200 poults was reared from 4 to 28 wk of age under four treatments as follows: full-fed controls (FF), low-protein diet (12% CP from 12 to 28 wk; LP), and reduced BW (10 or 20% lower BW than FF; R10 and R20). At photostimulation (28 wk), all birds consumed a commercial breeder diet ad libitum for the remainder of the study (48 wk of age). Body weight differed among treatments during most of rearing. The LP birds were similar in BW to the R10 birds at 28 wk of age. By 40 wk of age, growth curves of all treatments became similar, with the R20 group having lower BW. Feed restriction reduced frame size during rearing. Flock uniformity in the R10 and R20 treatment hens was reduced during rearing, but improved early in the breeder period. Feed restriction reduced breast muscle and abdominal fat pad weight early in lay, except for the LP group. Liver lipid content increased throughout the breeder period. Changes in liver weight followed the pattern of BW changes. Total carcass protein content changes in time reflected breast muscle mass changes. In R20 hens, carcass lipid content was reduced and protein content increased. Sexual maturity was delayed in the R20 hens. Body weight at first egg was negatively correlated with settable egg production (r = -.37, P < or = .0015). The R20 treatment is recommended for male-line turkey breeder hen candidates during rearing.

The purpose of this study was to examine the effect of hypoxia-induced hypoxemia and rate of growth on spontaneous dilatory cardiomyopathy in turkey poults. Turkey poults grown in a hypobaric chamber at an atmospheric pressure of 592 mmHg (calculated partial pressure of oxygen: 124 mmHg; calculated altitude and O2 equivalents: 2054 m and 16.3%) on a rapid-growth diet developed a mainly right ventricular dilatory cardiomyopathy typical of the acute form of spontaneous turkey cardiomyopathy (STC). Poults grown in a hypobaric chamber on a slow-growth diet had a much lower incidence of STC. Control poults at atmospheric pressure, altitude 295 m (calculated atmospheric pressure: 735 mmHg; partial pressure of oxygen: 154 mmHg, 20.26% O2), on a rapid-growth diet had an incidence of STC similar to that of the slow-growth hypobaric group, while those on a slow-growth diet had a lower incidence.

Turkey eggs were incubated at high altitude (1,700 m). Hatchability, hematology, and growth data were analyzed for the following treatments: 1) eggs receiving supplemented oxygen (SO) during the 1st wk of incubation (control eggs received no SO during the 1st wk); 2) eggs receiving SO during the 4th wk (control eggs received no SO during the 4th wk); and 3) the interaction effect of oxygen the 1st or 4th wk with SO the 1st and 4th wk or with no SO. Data analysis was carried out using orthogonal contrasts. Exposing incubating turkey embryos to oxygen the 1st wk or the 4th wk of incubation improved hatchability significantly (P less than or equal to .05) compared with the remaining treatments. When SO was given during the 4th wk of incubation, hemoglobin concentration in embryos decreased (p less than or equal to .05) during pipping compared with that of embryos without SO the 4th wk. Hemoglobin was increased (P less than or equal to .05) by increasing red blood cell numbers if SO was not given during Week 4, otherwise, the embryos increased (P less than or equal to .05) in mean cellular hemoglobin to increase hemoglobin. When oxygen was supplemented the 1st wk of incubation, reticulocyte maturation was slowed (P less than or equal to .05) compared with no SO the 1st wk. Oxygen exposure during the 1st wk or 4th wk of incubation reduced (P less than or equal to .05) body weights of embryos during pipping and at hatching compared with those of embryos in the remaining treatments. Oxygen supplementation during Week 4 affected (P less than or equal to .05) heart growth at the prenatal, internal pipping, and postnatal stages of respiration.(ABSTRACT TRUNCATED AT 250 WORDS)

Turkey eggs (Meleagris gallopavo) were incubated at an altitude of 1,707 m to test the effects of oxygen supplementation and increased eggshell permeability by removal of shell cuticle on embryonic hematology. Turkey embryo hematological indices measured were red blood cell count (RBC), hemoglobin concentration, packed cell volume, mean cellular volume, mean cellular hemoglobin, and percentage of reticulocytes. Although hemoglobin concentration measured during pipping increased as expected by increasing RBC, no significant differences were observed between oxygenation, or permeability treatments, or their interaction. Under the high altitude conditions of the present experiment, increased hemoglobin concentrations in all treatments corresponded to increased numbers of erythrocytes with constant mean cellular hemoglobin. None of the remaining hematological indices examined was affected by oxygen or permeability treatments. It was concluded that turkey embryos incubating at 1,707-m elevation make no additional changes in hemoglobin concentrations during the plateau stage in oxygen consumption (25, 26, and 27 days of incubation) when exposed to increased oxygen tension (151 mm Hg versus 135 mm Hg) or increased eggshell permeability (19.9 mg H2O/day per mm Hg versus 23.2 mg H2O/day per mm Hg).

Large White turkey hens were used in this study to investigate sperm storage in the hen throughout a 20-week breeding cycle. Hens were initially inseminated early or late and subsequently at 7-day intervals with either 20, 50, or 100 million sperm each time. Early inseminations (EI) were performed on Days 14 and 17 postlighting, and the late inseminations (LI) were performed on Days 21 and 24 postlighting. Fertility (percent) was calculated weekly for 20 weeks following the second initial insemination in each group. Fertility was greatest in EI hens for the 20-week period; the largest difference occurred between EI and LI treatments of the 50 million sperm/insemination group. A significant interaction was observed between time of initial insemination and sperm numbers per insemination. Overall fertility was improved with each increase in sperm numbers/insemination.

The eggshell water vapor conductance capable of maintaining constant water content in incubating turkey eggs was determined for three different egg weight classifications. Metabolism of the developing turkey embryos was altered by increasing or decreasing eggshell permeability. Eggshell permeability accommodated metabolic water in large eggs very well. Both relative poult weights and relative water content of embryos in large eggs at the plateau stage in oxygen consumption decreased or increased allometrically to the permeability treatment. However, among small and medium eggs, if eggshell permeability was increased, relative poult weights at hatching were much less than expected. This occurred despite the fact that relative water content of the eggs at 25 days of incubation was not similarly affected. The data suggest a biological asynchrony for egg size, metabolism, and water content of turkey eggs.

Research was conducted to develop an artificial insemination protocol optimizing the use of spermatozoa by turkey breeder hens. Large White turkey hens were inseminated on Days 14 and 17 postphotostimulation with 200 million spermatozoa from one male phenotype to fill the oviductal storage sites. Artificial inseminations were then performed weekly for 20 wk with different spermatozoa numbers of another male phenotype. Fertility and phenotype of each poult were determined at hatch to ascertain which insemination, initial or subsequent, was responsible for fertility. Inseminating weekly with 200 million viable spermatozoa cells resulted in better fertility but did not optimize the hen's utilization of spermatozoa from the initial inseminations. When fewer spermatozoa were inseminated weekly (50 million cells), more progeny were fertilized by spermatozoa already residing in the oviduct than would be expected. When the number of spermatozoa inseminated weekly was increased at intervals during a laying cycle, spermatozoa from the initial inseminations were utilized more efficiently, but fertility was depressed at times during the laying cycle. Gradually increasing weekly inseminated numbers of spermatozoa from 50 to 200 million viable cells/hen as the hens age results in nearly equivalent fertility to that resulting from insemination by 200 million cells each week. This represents a savings of 1.4 billion spermatozoa/hen over a 20-wk laying period.

Weight loss (12%) of turkey eggs in a commercial incubator by a weekly adjustment of relative humidity (RH) was compared in four independent trials with the industry standard of maintaining 58% RH. Trials 1 and 2 were conducted with eggs from one flock of recycled hens during their 14th and 20th week of lay, respectively. Trials 3 and 4 were conducted with first cycle hens during their 3rd and 10th week of lay, respectively. Hatch of eggs was significantly better when eggs were incubated to lose an optimum amount of weight. Hatch of fertile eggs was significantly improved (P less than .05) in all except Trial 2. Hatchability was best when loss of egg weight was not greater than 11.5% at 25 days of incubation.

Turkey egg hatchability at high altitudes was examined at two different oxygen tensions and two incubation temperatures. Incubating turkey eggs in a 149-torr oxygen environment at 37.7 C gave significantly better hatchability than a 109-torr oxygen environment at 37.5 C. Embryonic mortality data indicated that the higher incubation temperature in combination with increased oxygen tension decreased embryonic mortality during the 3rd and 4th wk of incubation and resulted in higher hatchability. The data suggest that hatchery managers at high altitudes should supplement with oxygen and incubate turkey eggs at higher temperatures than employed at lower altitudes.

1. Eggs from large white turkeys were incubated in tenuous and dense gas atmospheres. 2. Tenuous gases resulted in heavier embryos until the onset of the plateau stage in oxygen consumption when dense gas environments caused heavier embryos. 3. Tenuous gases decreased heart and lung weight but increased liver weight. 4. Oxygen supplementation in tenuous gases increased liver weights but had no effect on lung or heart weights. 5. The data suggest an interaction of gas density and partial pressures of individual gases which affects breathing and the physiology of developing poult embryos.