The occurrence of salmonellae during the rearing of broiler birds

1. The incidence of salmonellae was studied in two broiler houses at each of two commercial sites in an integrated commercial enterprise.

2. Salmonellae were not isolated from the empty, cleaned and fumigated houses and only on one occasion from the foodstuffs.

3. Salmonellae were isolated from the environment of the chicks and spasmodically from the litter, water troughs and dust.

4. The incidence of infection of the chicks did not influence the number of isolations of salmonellae from the environment of the birds during rearing.

5. Water in the water troughs rather than foodstuffs appeared to be the major oral route of infection or re‐infection of birds during rearing.     

Effect of age and sex on the chemical composition of edible offal and blood from broilers

1. The effects of age and sex on the proximate composition and inorganic constituents in edible offal and whole blood from a commercial British broiler chicken strain were studied.

2. Although the protein content of all tissues varied with age, the only statistically significant effect was on the level of protein in the gizzard.

3. The moisture content of the gizzard was significantly affected by age and blood by age and sex.

4. The fat content of the gizzard was significantly affected by age, as was the effect of sex on the fat content of blood.

5. The ash contents of heart and gizzard were significantly affected by age.

6. The phosphorus contents of the gizzard, heart and liver were significantly affected by age, as were the chloride content of heart and the calcium content of the liver. Blood potassium was significantly affected by sex. Fluctuations in the contents of other elements are discussed.

7. The variability in organ composition is discussed with respect to the degree of trimming and preparation of the samples.     

Protein and energy metabolism in two lines of chickens selected for growth on high or low protein diets

1. Genetic adaptation was investigated in broilers selected for seven generations on a normal (A) or a low (B) protein diet.

2. Protein and energy metabolism were studied in males from these selected lines fed on a diet of intermediate protein content.

3. All selected birds retained more nitrogen than those studied 10 years previously.

4. There was no difference in nitrogen retention between groups, although relative growth rate of group B birds was higher.

5. Heat productions relative to gross energy intake were 0.38 (group B) and 045 (group A). Energy retentions relative to gross energy intake were 0.39 (group B) and 0.35 (group A); the difference being primarily due to higher fat retention in group B.

6. Using a common maintenance requirement for metabolisable energy, group B utilised metabolisable energy for growth (0.78) better than did group A (0.71).

7. At 53 d of age plasma glucose (10%) and insulin (50%) were higher in group B than in group A.     

Effects of method of processing and chilling of Turkey carcasses on processing losses,water absorption and yields

1. The effects of wet or dry plucking, wet or dry evisceration procedures and method of chilling on processing losses and water uptake during chilling were studied using 19‐week‐old female large white turkeys.

2. Dry plucking increased weight loss due to plucking and eviscerating, and reduced chilled carcass yield.

3. Dry eviscerating increased carcass water uptake during chilling.

4. Pre‐chilling with running water increased carcass water uptake compared with chilling in ice and water alone.

5. Water uptake during chilling appeared to be increased by longer eviscerating time.     

Effect of substrate provision on performance and behaviour of laying hens in the pecking and scratching area of furnished cages

1. An experiment was set up to study the effects of substrate provision on performance and behaviour in the pecking and scratching area (PSA) of non-beak-trimmed hens housed in large furnished cages (60 hens/cage).

2. Three layer hybrids (two brown and one white, ISA-Hendrix Genetics, France) and two substrate conditions (with or without wheat bran automatically distributed on the PSA) were compared in a 3 × 2 experimental design with 12 cages per treatment.

3. Substrate distribution improved laying rate with no impact on the frequency of dirty or cracked eggs.

4. Substrate distribution improved the viability and body integrity of hens, which were not beak-trimmed.

5. Distribution of substrate tended to increase the number of hens in the PSA and enhanced their pecking and scratching behaviours but had a negative impact on the number of dust bath bouts per cage and encouraged dust bathing on the wire floor close to the feeder.

6. The white hens laid more eggs in the nest than the brown birds and used the PSA more for pecking, scratching and dust bathing at the end of the day than the brown hens, underlining the necessity to adapt cage furnishing and rearing management to specific behaviours of each layer genotype.     

Plumage loss in medium‐bodied hybrid hens: The effect of beak trimming and cage design

1. Plumage loss was assessed by visual scoring in 288, 78‐week‐old hens, housed as groups of four in battery cages, which differed in the design of the cage front and the position of the nipple drinkers.

2. Half the hens had undergone beak trimming at 18 weeks, but in many cases regrowth had occurred.

3. Plumage damage and loss was significantly reduced in beak‐trimmed birds compared with birds with normal beaks. Tier and cage design had no effect.

4. This finding supports the idea that feather pecking is the important factor in causing plumage damage, rather than abrasion.

5. A comparison between 64 birds in which beak regrowth had occurred, and 64 in which it remained truncated, showed that both groups had similar plumage scores.

6. It appears to be the beak‐trimming procedure which is important; subsequent regrowth being irrelevant.     

Cross performance as influenced by selection in pure lines

1. The resultant genetic gains in cross performance due to the individual, dam family and sire family (IDS) method of index selection for increased part‐period egg number in their parent lines are described.

2. A randombred control population of known pedigree was used to measure the environmental trends.

3. Selection in pure lines resulted in concomitant improvement in the crosses for the selected as well as the correlated traits.

4. Cross performance was comparatively more than expected on the basis of mid‐parent values, indicating involvement of non‐additive gene action in the expression of cross performance.

5. Crosses responded better to independent culling level selection for egg weight than their parents.

6. Heterosis appeared to increase in later generations as compared with initial generations of selection.     

A mathematical representation of the Ovulatory cycle of the domestic hen

1. The ovulatory cycle of the domestic hen (Gallus domesticus) was postulated to be the result of the interaction of two independent systems.

2. A circadian system was postulated to control the restriction of ovulation to an 8‐h period of the day under conventional 14 h light: 10 h dark regimes.

3. The final phase of follicular maturation was postulated to commence after ovulation of the preceding ovum in the hierarchy.

4. Ovulation was postulated to occur when a mature follicle was present in the ovary during the appropriate phase of the circadian‐linked system.

5. The predicted times of oviposition were within the standard error of the observed times of oviposition under 21‐, 24‐ and 28‐h photoschedules.

6. It was concluded that this hypothesis for the control of the ovulatory cycle of the hen is consistent with current knowledge.     

Evaluation of bone strength,keel bone status,plumage condition and egg quality of two layer lines kept in small group housing systems

1. The aim of the present study was to determine the influence of large (54 or 60) and small (36 or 40) group sizes and tiers of the small group housing system “Eurovent German” on tibia and humerus bone breaking strength, keel bone status, plumage condition and egg quality for two commercial layer lines, Lohmann Selected Leghorn (LSL) and Lohmann Brown (LB), at the same stocking density (890 or 830 cm²/bird).

2. In 4 consecutive trials, 4752 hens were recorded for keel bone status. Evaluation of plumage condition was made for 1440 hens and bone breaking strength was recorded for 1200 hens. A total of 4962 eggs were analysed for internal and external egg quality traits. Analyses involved 30 small group compartments per trial.

3. The layer line had a much more pronounced influence on humerus breaking strength than on tibia breaking strength.

4. Plumage condition, particularly on the neck, was positively correlated with humerus breaking strength in both layer lines.

5. An average of 34% of LB and 23% of LSL hens showed keel bone deformities, with higher proportions of slight deformities.

6. Slight keel bone deformities, rather than moderate to severe, increased significantly during the laying period.

7. Stocking density had no influence on bone breaking strength, keel bone status and egg quality traits.

8. LB layers had a 1.4-fold higher humerus, but only a 1.06-fold higher tibia breaking strength compared to LSL layers.

9. Tibia breaking strength was significantly affected by the interaction of group size and layer line. LSL layers in small groups had lower tibia breaking strengths than those of the large groups.     

The effects of restricted feeding on adrenal cortical activity in the immature domestic fowl

1. The effect of reducing food intake to 75% of the ad libitum intake was determined from hatching to 8 weeks in young Light Sussex chickens.

2. Restricted birds were lighter throughout the experiment.

3. Relative adrenal weight tended to be greater in restricted birds but the difference decreased with time.

4. There was no depletion of adrenal cholesterol: from week 5 there was a significantly greater amount in the adrenals of restricted birds.

5. After 1 week of restriction plasma corticosterone concentration was 73% greater than in controls. It decreased progressively, falling within the normal range at 5 weeks.

6. Restricted birds were hypoglycaemic from weeks 2 to 7 and hyper‐lipacidaemic throughout. A negative correlation between plasma glucose and free fatty acids was found.     

Selection for high specific gravity of eggs in a flock of Australorp hens

1. A realised heritability of 0.23 was obtained in an Australorp flock (S) selected for five generations for high egg specific gravity.

2. A comparison with an unselected control flock (C) over 50 weeks of lay in the final generation indicated a number of statistically significant correlated responses in commercially important traits in the S line in addition to the direct response of + 0.004 in specific gravity.

3. With an increase in specific gravity, there was a decrease of 3.4 in the percentage of soft‐shelled eggs laid.

4. The weight and albumen height of eggs measured within 1 hour of lay declined by 1.8 g and 2.1 Haugh units respectively.

5. There were reductions in the weight and albumen height losses of eggs stored over a 10‐d period (C 0.74, S 0.62 g and C 17.9, S 15.0 Haugh units respectively), so that at the end of this period the albumen heights in both lines were the same.

6. Average body weight and daily food intake were less by 0.28 kg and 7.5 g respectively.

7. Although there was no change in egg production, the average age at first egg was reduced by 11.3 d.     

The effects of trienbolone acetate implantation of Turkeys upon fluid balance and blood chemistry

1. The effects of implanting turkeys with trienbolone acetate (TA) upon fluid balance and blood chemistry were studied.

2. The Na and water contents of skeletal muscles were increased by TA treatment while K was unaltered.

3. The extracellular space expressed as a proportion of starved body weight was unaffected by TA implantation.

4. Plasma or serum concentrations of P, Ca, Mg, Na and K and activities of the enzymes aspartate aminotransferase [EC 2.6.1.1], creatine kinase [EG 2.7.3.2] and γ‐glutamyl transferase [EC 2.3.2.2] were not changed by TA treatment.

5. Packed cell volume was significantly increased by TA implantation after a delay of some 2 to 3 weeks while plasma protein concentrations were immediately decreased for a period of two weeks before nearly normal concentrations were obtained again.

6. Erythrocyte sedimentation rate was decreased by TA treatment, but serum protein electrophoretic pattern was unchanged.     

Effects of high inclusion rates of salseed meal in the diet of chicks

1. Starter diets containing either maize or salseed meal to replace the maize were fed to chicks over a period of 2 weeks.

2. Growth rate, food intake, food utilisation and proportion of dietary nitrogen retained were much poorer in chicks receiving salseed meal.

3. The chicks receiving salseed meal developed pathological lesions in liver and kidney.

4. The red blood cell count, white blood cell count, haemoglobin concentration and packed cell volume of the chicks receiving salseed meal were lower than those of chicks receiving maize.

5. The apparent metabolisable energy value of salseed meal was determined as 6.83 MJ/kg.     

An update on approaches to controlling coccidia in poultry using botanical extracts

1. This paper reviews the use of botanical extracts in the control of coccidial infection in poultry.

2. Some plants and their respective volatile oils and extracts have the potential to alleviate coccidiosis and reduce its severity.

3. Most plant bioactives improve some, but not all, aspects of coccidiosis with variable effectiveness against different species of Eimeria.

4. Difficulties in comparing research findings have arisen from the use of different experimental models, different active components and infectious dose of Eimeria.

5. Current knowledge of their potential anti-coccidial effects may provide guidance for the use of botanical extracts in the control of the coccidiosis.     

Effect of age and sex on the composition of muscle and skin from a commercial broiler strain

1. The effects of age and sex have been studied on the proximate composition and inorganic constituents in breast, thigh, drumstick and skin from a commercial British broiler strain (Ross 1).

2. Protein content generally increased with age in all muscles and decreased in skin. Protein content in skin of males was always higher than that in females.

3. Moisture content in all muscles decreased with age. In the skin, moisture decreased with age considerably more in females than in males.

4. Fat content increased with age in all tissues, while ash content of breast, thigh and skin decreased with age.

5. Phosphorus, chloride, magnesium and potassium all decreased with age in all the tissues. Thigh and skin calcium content were affected by age, as was the sodium content of drumstick and skin.

6. The sex effect on the inorganic constituents was variable.     

Influence of site and variety on starch,hemicellulose and cellulose composition of wheats and their digestibilities by adult cockerels

1. It has been shown that both the variety of wheat and the environment under which growth took place influenced the quantities of starch and cell wall carbohydrate contents of wheat.

2. The different varieties of wheat investigated contained different proportions of water‐soluble to water‐insoluble hemicelluloses.

3. By comparison of the arabinose to xylose ratios it was concluded that water‐soluble and insoluble arabinoxylans of wheat were branched to the same degree.

4. Starch from six wheat varieties grown in the U.K. was very well digested by adult cockerels and true metabolisable energy values of the wheats were high.

5. Small amounts of cell wall carbohydrates were digested by adult cockerels.     

Prevalence of and risk factors for Campylobacter colonisation in broiler flocks at the end of the rearing period in France

1. A study was conducted to estimate the prevalence and quantification by species of Campylobacter infection in broiler flocks at the end of the rearing period and to identify associated risk factors.

2. A questionnaire about the rearing period was completed and caecal samples were collected from 121 broiler flocks in Brittany, France, during 2008.

3. Campylobacter was isolated in 87 out of 121 flocks – a prevalence of 71.9% (95% CI, 63.7–80.1%), including 40.5% of Campylobacter jejuni and 29.8% of Campylobacter coli.

4. The average concentration, in positive flocks, was 7.96 log₁₀ cfu/g and ranged from 3.15 to 10.32 log₁₀ cfu/g.

5. The average concentration by species was: 7.57 log₁₀ cfu/g for C. jejuni and 8.44 log₁₀ cfu/g for C. coli.

6. There was a seasonal effect, with increased risk of Campylobacter colonisation in June, July and August (odds ratio (OR) = 9.59, 95% CI 1.15–79.75).

7. The other factors, associated with lower risk of Campylobacter colonisation, were the acidification of drinking water (OR = 0.33, 95% CI 0.13–0.86), antibiotic treatment at the beginning of the rearing period (OR = 0.20, 95% CI 0.07–0.55) and rodent control around the house (OR = 0.18, 95% CI 0.03–0.95).

8. The results show that hygiene practices and biosecurity measures could lead to a reduction in Campylobacter colonisation.     

Influence of age,sex and rearing systems on Toll-like receptor 7 (TLR7) expression pattern in gut,lung and lymphoid tissues of indigenous ducks

1. The objective of the experiment was to determine the influence of age, sex and rearing system on Toll-like receptor 7 (TLR7) gene expression in gut, lung and lymphoid tissues and physiological responses to stress in male and female indigenous ducks of Tamil Nadu, India.

2. A total of 36 ducks (12 males and 24 females) were obtained from local farmers and tissue samples of gut tissues (duodenum, jejunum, ileum and caecum), lymphoid organs (spleen and bursa) and lungs were collected in RNAlater solution followed by RNA extraction.

3. After normalisation to β-actin (endogenous control) qPCR analysis identified a significant effect of age, sex and rearing system on TLR7 expression in the ducks.

4. A significant up-regulation of TLR7 expression was observed in lungs, duodenum, jejunum, ileum and caecum of sexually mature (45 wk) compared with that of immature ducks (16 wk). Among sexes, male ducks had significantly higher TLR7 expression than female ducks.

5. Age and sex interactions were significant in lungs, duodenum, jejunum and caecum. Ducks reared in an extensive housing system showed significantly higher TLR7 expression in bursa, lungs, duodenum, ileum and caecum compared to intensively reared ducks. There were no effects of age, sex and rearing systems on TLR7 expression in the spleen.

6. The heterophil-to-lymphocyte ratio and serum corticosterone were higher in ducks reared on an intensive system compared with ducks from an extensive rearing system.     

The choline and sulphur amino acid requirements of broiler chickens fed on semi‐purified diets

1. Growth and food conversion efficiency of broilers were reduced at low dietary choline concentrations. These effects were accentuated by low dietary total sulphur amino acids (TSAA).

2. Increased mortality, perosis and other pathological changes involving a number of tissues were observed in birds fed on a low‐choline diet.

3. Methionine replaced part of the dietary requirement for choline at low dietary choline concentrations.

4. High dietary concentrations of choline (> 1 750 mg/kg) increased the requirement for dietary TSAA.

5. Increasing the dietary choline while maintaining the TSAA at an inadequate level may decrease performance.