Effects of short intermittent lighting on food consumption and performance of dwarf broiler breeders and progeny

1. Two hundred and sixty four dwarf broiler breeder hens were subjected to ad libitum or restricted feeding and to four lighting patterns: 15L (bright light):9D (dark), 15L:9d (dim light), 2L:10d: 1L:11d, (0.5L:3.5d) × 6.

2. Breeder hens fed ad libitum and subjected to either conventional or intermittent lighting ingested respectively, 25 g and 14 to 17 g more than hens restricted to 115 g/d.

3. Body weight was greater in hens fed ad libitum irrespective of the lighting pattern and of the amount of food intake.

4. Persistency of egg production was impaired by intermittent lighting.

5. Ad libitum feeding reduced egg fertility. The decrease was larger in breeder hens on intermittent lighting.

6. Hatchability was increased in hens submitted to the symmetrical lighting pattern (0.5L:3.5d).

7. Egg and chick weights were higher in hens fed ad libitum.

8. Shell index and shell breaking strength increased in restricted hens on the intermittent lighting pattern (0.5L:3.5d) × 6.

9. The best performance was obtained in restricted hens on the conventional lighting pattern.     

The effects of dietary calcium concentration on pheasant breeder performance

1. Thirteen pens of breeding pheasants (Phasianus colchicus) were fed ad libitum on diets containing 20, 23 or 27 g calcium/kg.

2. All diets were formulated to contain 10.6 MJ ME/kg.

3. Three pens of birds receiving the diet containing 23 g calcium/kg were also offered grit free choice containing 280 g calcium/kg.

4. There were no effects of treatment on food consumption or reproductive performance.     

Male-to-female aggression in cage-housed common pheasants (Phasianus colchicus) during the breeding season was not related to male plasma testosterone level

1. The aim of this study was to investigate if male-to-female aggression of common pheasants in the course of the breeding season was related to the concentration of plasma testosterone and/or other biochemical plasma indicators in male pheasants housed in breeding cages. The influence of season on the concentration of testosterone and biochemical indicators was also investigated.

2. Males were divided into non-aggressive and aggressive groups during the breeding season based on ethological evaluation. At the beginning, in the middle and at the end of the breeding season, a blood sample was taken from all males on the same day and the concentration of selected biochemical indicators and the total circulating testosterone in the plasma were determined.

3. Male-to-female aggression during the breeding season of pheasants was not influenced by the total plasma testosterone of males.

4. The concentration of total plasma testosterone in males decreased gradually during the breeding season.

5. Male-to-female aggression of pheasants did not have a significant effect on any of the assessed biochemical indicators.

6. The influence of the breeding season affected the activities of alanine aminotransferase and aspartate aminotransferase as well as the concentrations of glucose, magnesium, potassium and chloride in the blood plasma of cage-housed male pheasants.     

Long‐term selection for increased egg production 1

1. Results are presented of a closed White Leghorn flock selected for increased egg production over a period of 17 years.

2. During the last 7 years a random breeding sample of the production flock served as a genetic control.

3. Regressions of deviations of the production flock from the control flock on years, were highly significant for age at sexual maturity (‐2.18 d), egg production up to 275 d old (3.04 eggs), egg production to 500 d old (5.04 eggs) and egg weight at 14 months old (October) ( — 0.79 g).

4. The heritability of egg production up to 275 d old declined significantly from 0.35 to 0.19.

5. The realised heritability of egg production up to 275 d old was estimated to be 0.14.

6. The genetic correlation between egg production up to 275 d old and production in the residual part of the year was 0.48.

7. The rate of inbreeding in the production flock was 0.515% per generation and the expected rate of inbreeding in the control flock 0.21% per generation.     

Traits influencing the hatching performance of Japanese quail eggs

1. Japanese quail eggs from moderately heavier sires showed superior fertility; while fertile eggs from moderately heavier dams hatched slightly better than the eggs from lighter dams.

2. Higher rates of fertility and hatchability of Japanese quail eggs were observed from parents of 10 to 19 weeks of age, with peak fertility and hatchability at 14 and 12 weeks of age, respectively.

3. Sex ratios of 1:2 to 1:5 gave comparable fertility and hatchability results.

4. The hatching performance of quail eggs from cage and deep litter reared breeders was comparable.

5. Fertility and hatchability were directly proportional to the egg weight.

6. Quail egg shell colour, tints and blotches were found to influence hatching performance.

7. Storing quail eggs at 16 ± 2°C and 75 ± 5% relative humidity for more than 4 d reduced hatchability.

8. Hatchability of eggs stored at room temperature was improved if they were sealed in polyethylene bags.

9. Provision of light during the first 14 d of incubation resulted in a photo‐acceleration of about 3.2 h.     

Inheritance of body weight and rate of gain in Japanese quail

1. The effects of hatch date, location and sex on the body weight and rate of gain in Coturnix coturnix japonica were examined.

2. The data conformed to a mixed model and adjustments were made for the fixed effects sex, hatch date and location. Adjustment improved the precision of the estimates by reducing the error variances significantly.

3. Rearing equal numbers of birds from each family at different locations made the interactions negligible.

4. Weight gain was greater if illumination intensity up to 35 d was less.

5. Females were not heavier on the 1st day but were heavier on the 14th and 35th days than males.

6. Variance components and genetic parameters were estimated.     

Effect of lighting treatment on the productivity,health, behaviour and sexual maturity of heavy male Turkeys

1. Turkey poults (1620) were used to compare the effects of three lighting programmes on heavy strain males reared to 188 d: constant light (24L:0D, CON); increasing light (6L:18D at 7 d gradually increasing to 20L:4D by 63 d, INC); a pattern identical to INC followed by a decrease in daylength from 84 d to 10L:14D at 112 d (DID).

2. Lighting affected growth pattern but had no effect on body weight at 118 d or overall food to gain ratio.

3. Both INC and DID lighting reduced overall mortality in comparison to CON light primarily because of a reduction in the incidence of skeletal disease and spontaneous cardiomyopathy. INC and DID lighting increased the incidence of cannibalism.

4. Turkeys given INC or DID lighting had a superior ability to walk in comparison to those birds given CON light.

5. INC and DID males stood, ate and drank more frequently, and sat less often than CON turkeys during behavioural observation.

6. There were no lighting effects on carcase composition except that INC and DID birds had heavier keel bones. The ultimate force per cm² (stress) required to break femora was greater for turkeys given INC and DID lighting (P = 0.065).

7. Plasma testosterone concentrations at 117 d were 272.5, 115.2 and 29.5 pg/ml for turkeys given CON, INC and DID lighting, respectively (P= 0.072). Testosterone concentration was not related to growth rate.     

Metabolic and anatomical adaptations of light‐bodied chicks to intermittent feeding

1. Chicks of a light‐bodied strain were deprived of food on alternate days from 15 to 46 d of age.

2. Hyperphagia, amounting to twice the intake of control birds early in the experiment, occurred on the repletion day.

3. Final body weight attained 80% of that of the controls.

4. Body fat concentration decreased at first but returned to that of controls after 3 weeks.

5. A consistent hyperlipaemia was observed after food deprivation or restoration.

6. There was a marked increase in the digestive enzymes found in the small intestine, but not in the pancreas during the repletion day.

7. These responses may be considered as mechanisms to reduce the physiological manifestations of starvation.     

Behaviour of egg shell under compression in relation to deformation measurements1

1. The egg does not completely obey Hook's law when compressed between flat surfaces.

2. Deformation was not completely reversible due to crumbling at the points of contact with the force.

3. There are three components of non‐destructive deformation: (a) local deformation at the points of contact, (b) local surface crumbling and (c) deformation of the over‐all shell structure.

4. The latter two are uncontrolled, contributing to errors in the prediction of fracture force and depending on the non‐destructive force applied.

5. These effects should be considered in test selection and interpretation.

6. The optimum non‐destructive force was found to be 1 kg.     

Genotypic differences in speed and magnitude of response to ahemeral lighting

1. The paper compares between three genetically different lines in their egg weight and shell thickness response to a 28‐h cycle.

2. The response in shell thickness to ahemeral lighting was more rapid (2.2 d) than for egg weight (4.2 d).

3. Differences between genotypes were evident in both the speed and magnitude of response.

4. Overall, egg weight and shell thickness on the 28‐h cycle were 7% and 8% greater than on 24 h.

5. The allometric increase indicates that the increase in shell weight was on average 14% more than the increase in egg weight.     

Comparison of nutritive values of groundnut oil cake and Niger oil cake for laying pullets

1. The nutritive value of Niger oil cake (Guizotia abyssinica, Cass.) as a protein supplement for layers’ diets has been assessed.

2. Replacing groundnut oil cake (GNC) by Niger oil cake (NC) on an isonitrogenous basis, did not affect egg production, egg weight or the amount of food required per dozen eggs.

3. The percentage retention of nitrogen from diets containing 30% GNC or 30% NC was similar.

4. The ME value of NC used was 3025 kcal/kg.

5. It is concluded that NC can replace GNC in layers’ diets.     

Defective egg production in a population of dwarf white leghorns 1

1. The incidence of defective eggs during the first 60 weeks of age increased with time due to significant increases in broken and membranous eggs in a population of dwarf White Leghorn hens.

2. The production of double‐yolked eggs/100 hen d, high during the initial weeks of lay, rapidly declined and disappeared by 30 weeks of age.

3. The frequencies of broken, membranous and soft‐shelled eggs were significantly correlated with each other and with the frequency of multiple daily ovulations indicating a common aetiology for these defective egg types.

4. Double‐yolked eggs were produced by the heavier, earlier‐maturing pullets in the population.

5. Normal egg production in dwarf White Leghorns may be enhanced by reducing the incidence of defective eggs.     

Effects of adding yeast cell walls and Yucca schidigera extract to diets of layer chicks

1.?This research was conducted to determine the impact of diet supplementation with yeast cell walls and Yucca schidigera extract on the growth performance, antibody titres, and intestinal tissue histology of layer chicks.

2.?White, 1-d-old, Hy-Line hybrid chicks (n?=?840) were divided into 4 main groups, each comprising 7 replicates of 30 chicks (n?=?210): (1) control; (2) 1000?mg/kg yeast cell walls (YCW) added; (3) 1000?mg/kg Yucca schidigera extract (YE) added; and (4) 500?mg/kg YE?+?500?mg/kg YCW added. The trial lasted 60?d.

3.?Daily weight gain of the chicks was positively affected between d 45-60 in the YE and YCW?+?YE groups compared with the control group.

4.?Overall, feed consumption did not differ between the control and YCW, YE, YCW?+?YE groups during the 60?d study period. Feed efficiency was better in the YE and YCW?+?YE groups than in the control group between d 1-60.

5.?During the 60?d evaluation period, live weight gain, and final live weight were higher in YE and YCW?+?YE groups than in the control group.

6.?Antibody titres against infectious bronchitis and infectious bursal disease did not differ among the 4 treatments, but those for Newcastle disease were higher in the YE?+?YCW groups than in the control, YCW and YE groups on d 45.

7.?There were differences in intestinal histomorphometry between the 4 treatments. The height of the jejunal and ileal villi was greater in the YE and YCW?+?YE groups than in the control and YCW groups

8.?It can be concluded that YCW and YE supplementation for layer chicks is beneficial for growth performance and intestinal histology during the 1-60?d growing period.     

Associations between body weight and rectal temperature in turkey poults

1. Associations between body weight and rectal temperature were observed in female turkeys.

2. Turkeys with lower weights between 13 and 30 d of age tended to have higher temperatures.

3. Turkeys with lower weights at 7 d exhibited depressed body temperatures.

4. Higher or lower body temperatures may be associated with poorer performance depending on the time of appearance.     

Some observations on the caecal micro‐flora of the chick during the first two weeks of life

1. Changes in the caecal flora of chicks aged from approximately 3 h to 14 d were studied.

2. Counts obtained by means of a conventional anaerobic plating method and a method for the stricter anaerobes remained comparable throughout but occasionally it was found that strains of anaerobic bacteria isolated from the predominant flora of 4‐ to 14‐d‐old birds could not be grown when tested by the conventional method.

3. During the 14‐d period approximately 100% of the organisms isolated on anaerobic plates utilised uric acid up to the third day but the incidence subsequently declined and in one case represented only 4% of the total flora.

4. The predominant uric acid‐utilising bacteria were Streptococcus faecalis and Escherichia coli up to 3 d of age and various types of anaerobic bacteria thereafter.

5. None of the isolates showed an absolute requirement for uric acid.     

Effect of egg composition on hatchability and on growth and slaughter characteristics of meat-type chicks

1.?Using the so-called TOBEC (Total Body Electrical Conductivity) method, which allows the determination of egg composition in vivo, correlations between egg composition, hatchability and hatched chicks’ development were studied.

2.?A total of 1500 hen eggs (Ross-308) were measured by TOBEC, and eggs with extremely high (10%, n = 150), extremely low (10%, n = 150) and average (10%, n = 150) electrical conductivity values were chosen for further investigation.

3.?During the incubation period, it was observed that eggs with high electrical conductivity had a significantly higher mortality than eggs with low electrical conductivity.

4.?It was observed that both the increase in electrical conductivity at the same egg weight, and the increase in egg weight at the same electrical conductivity resulted in an increase in the hatching weight.

5.?It was found that the dry matter, protein and fat content of the chicks hatched from eggs with low electrical conductivity was higher at hatching than that of the chicks hatched from eggs with high electrical conductivity.

6.?At 42 d of age the liveweight of cocks and pullets hatched from eggs with low electrical conductivity was 3·2 and 8·2% higher than the liveweight of cocks and pullets hatched from eggs with high electrical conductivity.

7.?Because of the higher liveweight at slaughter, there was a significant superiority of the chicks hatched from eggs with low electrical conductivity in the case of the examined carcase traits at slaughter.

8.?Similar tendencies were found also in the ratios of carcase variables to liveweight, but the between group differences were not statistically significant in this case.

9.?Based on the results it was concluded that TOBEC seems to be a useful method for separating eggs with different composition.

10.?This could be a good starting point for further in vivo investigations in order to clarify the effect of egg composition on hatchability and further development.     

Effects of food intake regulation on the energy metabolism of laying hens

1. The effects of dietary energy restriction on the energy metabolism of post‐peak‐of‐lay hens of two hybrid layer strains were studied by indirect calorimetry.

2. Starving and resting rates of heat production (SHP and RHP) were measured, over 1‐d periods, at intervals during a 25‐week period in which the experimental birds were individually restricted to 80% of their previous energy intake ad libitum.

3. In both strains mean RHP per bird was about 7% lower in the restricted birds than in controls fed ad libitum, but when RHP was expressed in terms of metabolic body size (kg^0.75) the two groups did not differ.

4. Mean SHP per bird was about 18% lower in the restricted birds of both strains than in the corresponding controls; the decrease in SHP per kg^0.75 was 12%.

5. Heat increment of feeding and calculated maintenance energy were higher, and net availability of metabolisable energy for maintenance and production was lower, in the restricted than in the control groups.

6. Gross efficiencies of egg production, in terms of both mass and energy, increased in the restricted birds.

7. Live‐weight and total carcass energy after 25 weeks of restriction were respectively about 15% and 30% lower in the restricted groups of both strains than in the groups fed ad libitum.     

Storage of hatching eggs: The effect on total incubation period

1. A time‐lapse photographic technique has been developed which enables routine recording of the hatching times of up to 192 chicken embryos.

2. Storage of eggs for 14 d caused a delay of 134 h in the mean total incubation period.

3. Female embryos hatched about 3 h earlier than males in the non‐stored eggs but there was no difference between the sexes in eggs stored for 14 d.

4. Rate of weight loss during incubation was similar in both non‐stored and stored eggs: there was no relationship between weight loss at 19 d incubation and total incubation period.

5. Hatchability of fertile eggs was 19.5% lower in eggs stored for 14 d and proportionately more embryos died between 4 d and 18 d incubation than in the non‐stored eggs.     

Effect of progesterone on the magnum proteins during primary stimulation of chick oviduct

1. The effect of progesterone on the secretion of protein by the magnum of 5‐d‐old, female chicks was determined.

2. The supernatant prepared by centrifuging an homogenate of the magnum at 105 000g was found, by immunodiffusion, to contain an antigenic component which precipitated the antisera for conalbumin 1, conalbumin 2 and ovalbumin after 5 d treatment with progesterone: there was no reaction to ovomucoid, lysozyme and avidin antisera.

3. Disc‐electrophoresis of the homogenate revealed two bands at the site of ovalbumin.

4. Incorporation of ³H‐lysine into the magnum proteins of progesterone‐treated chicks did not differ from that of controls.

5. The secretion available in the magnum may be only a transudate from the serum and not a true secretory product. Progesterone behaved qualitatively as oestrogen in this study although the action is much less pronounced and was delayed.     

The bacterial flora of unhatched eggs

1. The methods of bacteriological examination of hatchery waste eggs were compared.

2. Using one of these methods a survey was conducted on eggs which had failed to hatch from commercial hatcheries.

3. An assessment of the level of contamination in the eggs examined indicated an average level of contamination of 12.7%.

4. The contaminating flora was composed mainly of Micrococcus sp. and Enterobacteriaceae, with Streptococcus sp., Staphylococcus sp., Bacillus sp. and Pseudomonas sp. present at lower levels.

5. Various interrelationships between contamination and hatchability are discussed.