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Biomedical subjects

E A Butler

Publications and source records attributed to E A Butler.

13 recordsLinked to original sources
PubMed2006

Free-range village chickens on the Accra Plains, Ghana: their husbandry and productivity.

A cross-sectional[4pc] survey investigating husbandry and productivity of free-range village chickens was carried out in four administrative districts within 60 km of Accra. Responses were provided by 101 men and 99 women. The mean (SD) household flock size was 28.7 (25.97) and the median was 20. The factors included in the final model investigating variance in flock size were sex of the respondent (p = 0.011), administrative area (p = 0.004), the numbers of members in the household (p = 0.017) and the number of cattle, sheep and goats owned by the household (p = 0.031). Chickens were owned by individual members of the household, but women and children were the predominant providers of care for chickens. All respondents described their chickens as scavengers that were provided with supplementary feed, and over 80% of respondents named maize as a supplementary food source. Approximately 50% of respondents claimed difficulty in providing supplementary feed, with the degree of difficulty varying between administrative areas (p < 0.001). A majority of respondents (approximately 65%) claimed that their chickens laid 3-4 clutches of eggs per year. Over 70% of respondents estimated that each clutch contained 10-20 eggs, and approximately 70% of respondents estimated that 75% of the eggs hatched. Opinions on mortality varied, but 60% of men and 70% of women estimated that between 50% and 75% of both chicks and adult birds died each year. Approximately 80% of respondents named Newcastle disease as the most important health issue. The opportunities for and consequences of controlling Newcastle disease are discussed.

Animal Feed↗
PubMed1995

New intermittent lighting programme (the Reading system) for laying pullets.

1. Two intermittent lighting systems for laying hens are: the Biomittent system, using an asymmetric pattern of 0.25L:0.75D for 16 h followed by 8D, which entrains oviposition to 24 h cycles and, compared with standard lighting programmes, gives the same egg number and egg size but a smaller feed cost, and a symmetrical system (4[3L:3D]) which allows intervals between ovipositions to stretch, giving bigger eggs with thicker shells, but yielding fewer eggs and achieving no saving in food intake. 2. A new system was devised to combine the increased egg size and shell thickness, characteristic of symmetrical intermittent lighting programmes, with the reduction in food intake which is a feature of programmes that reduce total activity time. The pattern tested was 24(0.25L:0.75D). 3. The results of 2 trials showed that this new system gives about 2% fewer eggs than conventional (Step Up) or Biomittent lighting with a 2% increase in mean egg size and a 3% improvement in shell thickness at the end of the laying year. Feed consumption with the new system was similar to that under Biomittent lighting and 6% lower than that recorded for Step Up lighting. 4. Mortality was lower with the new system than with Step Up lighting, but not significantly so. From the evidence of other trials it is argued that intermittent lighting programmes which provide less than 8 h total illumination in 24 h generally reduce laying house mortality and may be regarded as beneficial to the welfare of the hen.

Aging↗
PubMed1995

A test for photorefractoriness in high-producing stocks of laying pullets.

1. Pullets of 2 high-producing commercial stocks (both brown-egg layers) were exposed to 5 different lighting patterns between 18 and 72 weeks to test the hypothesis that photoperiods used in commercial lighting programmes early in the laying year may be unnecessarily long and, by accelerating the development of photorefractoriness, may contribute to the decline in egg production observed after the initial peak. Two rooms of 288 pullets were allocated to each treatment. 2. The rate of lay observed with a Step-Up treatment which gave increases in photoperiod from 8L:16D at 18 weeks to 15L:9D at 27 weeks of age was not significantly different from that of treatments which held the birds on 11L:13D during peak egg production but gave increments up to 15L:9D later in the laying year. 3. A control group maintained on 11L:13D from 20 to 72 weeks laid 295 eggs per bird housed and a further group held on 8L:16D from 0 to 72 weeks laid 284 eggs per bird. These yields were lower than the Step-Up treatment (299 eggs) but show the potential of modern hybrid stocks to lay prolifically even without light stimulation. 4. It is concluded that the stocks tested in this experiment showed no advantage when given lighting programmes in the first laying year which were designed to minimise the adverse effects of photorefractoriness.

Aging↗
PubMed1991

Optimum isoleucine requirement of laying hens and the effect of age.

1. Medium weight laying hens were used for an assay to determine their isoleucine requirement between 26 and 36 weeks of age and again between 46 and 56 weeks of age. 2. Two isoleucine-limiting mixtures were formulated with similar amino acid profiles, one containing 198 g and the other 110 g crude protein per kg diet. These mixtures were blended to give a series of 11 diets with isoleucine contents ranging from 7.6 to 3.8 g/kg. The lowest protein diet was also fed with a supplement of L-isoleucine. Each of the 12 diets was given to 5 groups of 24 laying hens. 3. The daily isoleucine requirement of individual laying hens was estimated to be 9.48 mg/g egg output plus 44.47 mg/kg body weight per day for the 1st period and 12.11 mg/g egg output plus 6.86 mg/kg body weight per day for the 2nd period. Calculated optimum intakes of isoleucine for various ratios of cost of input to value of output are tabulated. For example, for a flock of medium weight hens producing an average of 50 g daily egg mass, the optimum isoleucine intake (mg/hen d) varied between 760 and 890 varying for ratios of costs to egg prices. 4. It is concluded that the isoleucine required per day does not decrease during the first laying year despite a decrease in rate of egg output.

Aging↗
PubMed1991

Optimum threonine requirement of laying hens.

1. One experiment was conducted with medium weight laying hens to determine their threonine requirement between 28-38 weeks. 2. Two threonine-limiting diets of identical protein quality (summit-dilution) were used and, by dilution, ten protein contents were produced supplying 2.7 to 5.4 g total threonine/kg diet. The diet with the lowest protein was also supplemented with synthetic L-threonine. Each diet was fed to 5 groups of 24 laying hens. 3. The daily threonine requirement of the individual laying hens was estimated by direct methods to be 8.7 mg/g egg output plus 43.49 mg/kg body weight for this experiment. Calculated optimum intakes of threonine for various ratios of costs of input to value of output are tabulated. For example, for a flock of medium weight laying hens producing an average of 50 g daily egg mass, the optimum threonine intake (mg/hen d) varied between 700 and 710 for cost ratios (k-values) varying between 0.002 and 0.001.

Amino Acids↗
PubMed1988

Experiments with the Cornell intermittent lighting system for laying hens.

1. Two experiments were conducted to provide further evidence about rate of lay under the Cornell lighting system (2L:4D:8L:10D). Each used 1728 hens of each of 2 brown-egg stocks in 12 light-proof rooms. 2. In the first the Cornell system was compared at 2 light intensities (average values 2 and 10 lux) with a conventional step up lighting programme. In the second, Cornell lighting was introduced at 18, 21 or 24 weeks of age and compared with a step up programme. 3. Total egg output was essentially the same from the Cornell lighting system, using 10 h light/d, as from the step up programme using 16 h/d. When the Cornell system was applied abruptly at 18 weeks to pullets which had been reared on short days (8L:16D) sexual maturity was advanced, resulting in an increase in mean rate of lay to 72 weeks of age and a reduction in mean egg size. Application of the Cornell system from 21 or 24 weeks gave the same egg numbers and the same egg size as the step up programme. 4. Food intake was about 2% lower with the Cornell treatment in both experiments. Although this difference was not quite significant in either, it probably reflects a real effect of the reduced hours of light. It represents a greater potential cost saving than the reduced electricity consumption. 5. Birds in rooms with an average light intensity of 2 lux laid slightly fewer eggs but their eggs were 0.5 g heavier than those laid in rooms maintained at 10 lux. There were no interactions between light intensity and light pattern or between stocks and light pattern.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Experiments with the Bio-mittent lighting system for laying hens.

1. Two experiments are described in which a system of intermittent lighting (15 min light followed by 45 min dark for 15 h, then 15 min light, 30 min dark, 15 min light and 8 h dark) was applied to laying pullets from 37 to 72 weeks of age. A step-up lighting programme was used as a control treatment (8L:16D from 0 to 18 weeks, photoperiod increased by 20 min each week from 18 to 41 weeks, 16L:8D from 41 to 72 weeks of age). 2. Food consumption was reduced by about 5% when intermittent lighting was in use and by 3.8% for the period from 18 to 72 weeks. 3. Rate of lay and egg weight were similar for intermittent lighting and the control treatment, provided that protein content of the diet was adjusted to maintain an adequate amino acid intake. 4. In the second trial 2 stocks, 2 stocking densities confounded with 2 temperatures and 2 types of food trough were used. Each of these factors affected food intake and it was found that more food was saved by intermittent lighting when intake was high and less when it was low. The proportion saved was approximately 5%. 5. Mortality was slightly but not significantly lower in both experiments where intermittent lighting was used. This may indicate that caged pullets are under less stress when intermittent lighting is used.

Animals↗