British Poultry Science

Shabalina, A. T.

doi: 10.1080/00071668408454870pmid: 6478275

Abstract 1. Cockerels were tested for dominance rank (509 tests) and sexual activity (79 tests). Fear responses to a human were estimated using a five‐point scale (264 tests). 2. The sexual activity of calm cockerels was 135·5 units, and that of fearful ones 66·6 units (P < 0·05). There was a tendency to better fertility by cockerels from the first group (86·4% to 81·1%). In addition, eggs from this group showed improved hatchability compared with the fearful ones (88·5% to 77·6%). 3. There was no clear relationship between dominance rank and fear score.

Shurlock, T. G. H.; Forbes, J. M.

doi: 10.1080/00071668408454871pmid: 6478276

Abstract 1. The hepatic portal veins of cockerels were catheterised to study the effects of 3‐h infusions of nutrient solutions on voluntary food intake. 2. An amino acid mixture, infused at rates up to 800 mg N/3 h, depressed intake of a standard diet in a significant linear manner (intakes with the highest dose and control: 1·6 g and 22·6 g/3 h respectively). 3. Infusion of the highest dose into the jugular vein had a smaller and nonsignificant effect (17·2 and 25·3 g/3 h). 4. The effects of combined infusion of amino acids and glucose into the portal vein on food intake were approximately additive.

Charles, D. R.

doi: 10.1080/00071668408454872pmid: 6478277

Abstract 1. A quantitative literature review has been used as the basis of an empirical simulation model of the responses in food intake and egg output of laying hens to temperature, light pattern, light intensity, feeding system type, crude protein, methionine, lysine and metabolisable energy. The financial consequences are considered, by the calculation of gross margin of egg value minus food cost. 2. Response to protein intake in an optimal environment is taken as the first limiting factor. Depressions below the maximum are calculated for sub‐optimal environments. 3. The model was tested against a sample of flocks for which detailed records were available, and found to give realistic answers. A FORTRAN program was written which calculates egg output and food intake by 4‐week production periods, permitting the user to examine the effects of management changes made during lay. Shortened versions of the model, based on annual values have been written for a programmable calculator.

Bornstein, S.; Plavnik, I.; Lev, Y.

doi: 10.1080/00071668408454873pmid: 6478278

Abstract 1. In four trials during consecutive years individually‐caged birds were weighed at first egg, and in the first two trials they were then killed to determine abdominal and skin fat, in order to establish whether there is a minimal body weight and/or body fat pool required for the start of egg production in broiler breeder hens. 2. There were negative correlations ranging from significant to negligible between body weight and age at first egg. For birds of the same strain on a conventional food restriction regimen, the average weight range at first egg in the four trials was 3·3 to 3·7 kg, which may be a strain characteristic. 3. In spite of severe food restriction, all birds were very fat at first egg. The correlations between fat concentration and age at first egg were negative. 4. In mature pullets a minimum concentration of stored, easily mobilised fat may be essential for yolk formation and ovulation.

Abplanalp, H.; Tai, C.; Napolitano, Dona

doi: 10.1080/00071668408454874pmid: 6478279

Abstract 1. Data from 16 inbred lines derived by three generations of full sib mating from a common outbred base population were used to estimate genetic correlations between body weight, abdominal fat content, follicle number, liver weight, egg weight and egg number using between‐line variances and covariances. 2. High genetic correlations were found between body weight, fat content and egg weight. Low genetic correlations were found between follicle number and all traits other than egg weights. 3. Theoretical expectations and low correlations within lines led to the conclusion that environmental correlations among the traits considered were very low.

Damron, B. L.; Goodson, S. R.; Harms, R. H.; Janky, D. M.; Wilson, H. R.

doi: 10.1080/00071668408454875pmid: 6478280

Abstract 1. The possibility of β‐carotene affecting production of hens or hatchability of eggs was studied over 252 d with diets based on white maize containing 0, 1·5, 6·75 or 15 mg added β‐carotene/kg. 2. Egg production, food intake, food utilisation, egg weight, and egg specific gravity were not affected significantly by jS‐carotene. Egg fertility, hatch‐ability and final body weights of hens were also not significantly influenced. 3. Reflectance measurements showed that dietary β‐carotene resulted in increased deposition and more intense pigmentation in the egg yolk.

Sterling, R. J.; Sharp, P. J.; Klandorf, H.; Harvey, S.; Lea, R. W.

doi: 10.1080/00071668408454876pmid: 6434159

Abstract 1. Changes in concentrations of plasma luteinising hormone (LH), follicle stimulating hormone (FSH), androgen, growth hormone (GH), prolactin (Prl), thyroxine (T4) and triiodothyronine (T3) were measured during growth and sexual maturation in broiler cockerels reared in continuous light to 7 weeks and 14 h light/d thereafter. 2. Concentrations of LH and FSH began to increase between 13 and 15 weeks, while those of androgens increased between 16 and 17 weeks. FSH concentration increased faster than that of LH. 3. Concentrations of GH and Prl were high at 3 weeks; that of GH decreasing progressively between 3 and 14 weeks of age and thereafter remaining low, while that of Prl was low between 5 and 9 weeks, relatively high between 10 and 13 weeks, and then temporarily decreasing before increasing progressively during sexual maturation. 4. Concentrations of T3 and T4 were higher in juvenile than in adult birds.

Abplanalp, H.; Peterson, S. J.; Okamoto, S.; Napolitano, Dona

doi: 10.1080/00071668408454877pmid: N/A

Abstract 1. Positive heterosis effects for the proportion of yolk, and negative heterosis for the proportion of albumen were found in crosses of six inbred Leghorn lines. 2. Three‐way crosses showed no consistent change in egg composition when compared with matched two‐way crosses. 3. Large differences in egg composition were found between inbred lines. 4. The egg composition of two‐way crosses was highly predictable from the performance of their parents, while specific combining effects as measured by deviations from offspring—parent regression were relatively unimportant.

Johnson, R. J.; Choice, Amanda; Farrell, D. J.; Cumming, R. B.

doi: 10.1080/00071668408454878pmid: 6478281

Abstract 1. Production responses of laying hens to food restriction during rearing were measured in two trials. 2. Food was restricted by two methods: time restriction (TR, food continuously available for 24 to 30 h each 72 h) and proportion restriction (PR, daily allocations of about 60 to 70% of that consumed by ad libitum fed birds (F))‐ 3. The rearing treatments were applied from 42 to 162 d and from 56 to 168 d of age in experiments 1 and 2 respectively. All birds were fed ad libitum in the laying period to 437 d and 476 d of age in experiments 1 and 2 respectively. 4. Body weight was reduced significantly in both experiments by both methods of restriction, but more so by TR. Marked compensatory growth accompanied the high food intake following the end of food restriction. 5. There was a significant increase in average egg weight concommitant with a change in the relationship between egg weight and age. Possibly this is due to an altered pattern of food intake at onset of lay.

Wallis, I. R.; Balnave, D.

doi: 10.1080/00071668408454879pmid: N/A

Abstract 1. Apparent amino acid digestibilities determined in the lower ileum of broilers given free access to a diet containing normal or heat‐damaged soya protein were similar to “true” digestibilities determined with excreta using the Sibbald rapid bioassay. 2. Higher ileal digestibilities were obtained with the Farrell rapid bioassay than with birds given free access to food. This pattern was reversed when measurements were made on excreta. 3. Maximum absorption of amino acids had occurred by the time the di‐gesta had reached the upper ileum in birds fed on normal but not heat‐damaged soyabean protein. 4. Heat damage to the soyabean protein was detected with all the bioassay procedures.