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Biomedical subjects

F N Reece

Publications and source records attributed to F N Reece.

At least 19 recordsLinked to original sources
PubMed1987

Influence of a wheat diet on mortality of broiler chickens associated with necrotic enteritis.

In an experiment to determine methods of incorporating soft winter wheat into broiler diets, a significant increase in mortality was observed in broilers fed wheat in crumbled diets. This increase in mortality was associated with necrotic enteritis with Clostridium perfringens indicated as the causative pathogen and complicated by a coccidiosis outbreak. When yellow corn was used in the diet, mortality was 2.9%. Use of all wheat, ground with a hammer mill, increased mortality to 28.9%. However, roller mill-ground wheat diet resulted in a mortality of 18.1%. When the grain component was approximately 50% wheat and 50% corn, mortality was 12.6% for broilers fed hammer mill-ground wheat and 3.4% for roller mill-ground wheat. Grain and feed were tested for several mycotoxins. Low levels of deoxynivalenol were found in both corn and wheat diets, but no differences between the corn and wheat-based diets were found that would explain the incidence of enteritis.

Animal Feed↗
PubMed1986

Relationship of photoperiod and feed intake to thyroid hormone concentration.

Broilers, obtained from a commercial hatchery, were reared in two environmental chambers with controlled temperature, humidity, and lighting in three trials. Lighting was continuous for 0 to 7 days and 12L:12D thereafter. Temperatures, initially 32.2 C in Trials 1 and 3 and 29.4 in Trial 2, were gradually lowered during rearing. At the end of the trials, temperatures were 21.1, 10.0, and 23.9 C in Trials 1, 2, and 3, respectively. Feed and water were provided ad libitum until 21 days in Trials 1 and 3 and 28 days in Trial 2. During the subsequent 14 days in each trial, feed was provided 12 hr/day with one chamber receiving feed during photophase (LF) and the other receiving feed during scotophase (DF). Plasma samples for 3,5,3'-triiodothyronine (T3) and thyroxine (T4) assay were obtained at 3-hr intervals throughout a 24-hr period at the end of the 14-day treatment period. During the 14-day treatment period, the weight gain of the DF broilers averaged 90% of the LF broilers for the three trials. This demonstrates broilers adapted very well to feeding during scotophase. The T4/T3 ratio increased during fasting and decreased when feed was available, but photoperiod had no discernible effect. The change in T4/T3 ratio over 24 hr was greater at high than at low environmental temperatures.

Animals↗
PubMed1986

Effect of acclimation and heat stress on thyroid hormone concentration.

In three trials, broilers were exposed to either moderate-constant or high-cyclic temperatures for 3 days. Broilers in both treatments were exposed to 41 C and high humidity over a 4- to 6-hr period on the 4th day. Blood samples, collected before and at the end of the heat exposure, were assayed for thyroid hormones. Neither acclimation nor severe heat exposure consistently affected triiodothyronine (T3) or thyroxine (T4) concentration. It appears the mechanism of short-term acclimation involves endocrine or physiological responses other than changes in circulating thyroid hormone concentrations.

Acclimatization↗
PubMed1986

Use of ammonium chloride and sodium bicarbonate in acute heat exposure of broilers.

Ammonium chloride (NH4Cl) and sodium bicarbonate (NaHCO3) were added separately to the drinking water of 42- to 52-day-old broilers. Birds were given access to the water ad libitum for a total of 42.5 hr consisting of 18.5 hr prior to an 8-hr interval of severe heat exposure and a further 16 hr-post exposure. Water and feed intake during the treatment period were unaffected by either NH4Cl at 6.25 g/liter (.63%) of distilled water (DW) or NaHCO3 at 3.15 g/liter (.32%) DW. Water intake was increased by approximately 20% in birds given water containing 6.25 g of NaHCO3/liter (.63%) DW, while both feed and water intake were severely limited by NH4Cl at 31 g/liter (3.1%) DW. Blood pH of birds was substantially lowered by consumption of NH4Cl, while consumption of NaHCO3 did not significantly affect blood pH. Blood pH of all treatments increased during the heat exposure period and declined afterward; however, blood pH change appeared to be more pronounced for birds receiving the NH4CL. A correlation coefficient (r = -.31) existed between blood pH and mortality, while a correlation (r = -.72) was demonstrated between water consumption and mortality.

Ammonium Chloride↗
PubMed1984

Effect of atmospheric ammonia on pullets at point of lay.

Results obtained show that pullets exposed to 200 ppm atmospheric ammonia for 17 days had a reduced feed intake and reduced growth rate when compared to controls. After the ammonia exposure period at point of lay, percent egg production was less and mortality greater for the ammonia exposed group versus the controls.

Air Pollutants↗
PubMed1984

Effect of differing temperature cycles on broiler performance.

Commercial male broilers were used in five trials conducted to determine whether lowering the temperature during the cool portion of the 24-hr period in summer affected broiler performance. Treatments used were 24-hr linear temperature cycles ranging from a high of 35 C to a low of either 26.7 or 21.1 C. Results obtained showed that lowering the low portion of the temperature cycle from 26.7 to 21.1 C during the 24-hr period significantly increased broiler body weight at 48 days of age.

Animal Feed↗
PubMed1984

Response of broiler chickens to dietary energy and lysine levels in a warm environment.

Two trials were conducted to determine the response of 23- to 47-day-old broiler chickens to dietary lysine and energy levels when reared in a 26.7 C environment. Broiler finishing diets, which contained 3100, 3175, 3250, or 3325 kcal ME/kg of feed were fed in combination with either .308 or .322% lysine/Mcal (kg) with a constant 18.7% dietary protein. Male and female body weights were not statistically different (P less than .05) among dietary energy levels when both sexes were fed .308% lysine/Mcal (kg). When the male chicks were fed .322% lysine/Mcal (kg), body weights increased with increasing dietary energy level. Feed utilization also increased with increasing dietary energy level when broilers were fed either .308 or .322% lysine/Mcal (kg). These data suggest that the body weight response to dietary energy level when broilers were reared in a warm environment will occur only when adequate amino acid levels are employed. The dietary energy requirement is at least 3250 kcal ME/kg of feed when 23- to 47-day-old broilers are fed .322% lysine/Mcal (kg) and reared in a hot environment but appeared to be lower when broilers were fed .308% lysine/kg of feed.

Animals↗
PubMed1984

The effects of feed form, protein profile, energy level, and gender on broiler performance in warm (26.7 C) environments.

Two dietary energy levels, 3032 and 3109 kcal ME/kg, and four protein levels of approximately 17, 18, 19 and 20%, were used to formulate eight grower-finisher rations used in four feeding regimens used in both mass and crumble form fed to broilers in a warm (26.7 C) environment. The protein levels were established by specific lysine: energy ratios with methionine plus cystine at a constant percentage of lysine. Best overall broiler performance was obtained with a feeding regimen using the higher energy level with high-protein profile in crumble form; feed conversion for this regimen was improved 5.4% and body weight 3.2% over the poorest performing diet, which was the lower energy diet with low-protein profile in mash form. Overall, crumbling improved feed conversion 1.5% and increased body weight 2.2%, the high-protein profile improved feed conversion 2.0%, and increasing metabolizable energy from 3032 to 3109 kcal/kg improved feed conversion 2.2%. Feed conversion for males was 3.3% better than for females.

Animal Feed↗
PubMed1983

The effects of temperature and age on body weight and feed efficiency of broiler chickens.

Mixed sex, commercial broiler chickens were grown at three environmental temperatures: 15.6, 21.1, and 26.7 C. Starting at 35 days, body weights and feed conversions were measured at 3- to 5-day intervals to 55 days of age. Both body weights and feed conversions were linear with age over the time range indicated. The growth rates at 26.7 C were 6% less at 35 days and 10% less at 55 days than at 15.6 C. When equated for body weight differences, there was no difference in feed conversion between broilers grown at 21.1 and 26.7 C. Birds grown at 15.6 C consumed more feed per unit of weight than at the other two temperatures. At 49 days of age, the birds grown at 15.6 C required 16% more feed than those grown at 26.7 C; however, when weights were equated at 2000 g, those grown at 15.6 C required only 3% more feed than those grown at 26.7 C.

Aging↗
PubMed1982

The effect of environmental temperature on sensible and latent heat production of broiler chickens.

Sensible and latent heat (moisture) production data were obtained for broiler chickens grown from 3 to 7 weeks of age on litter at three environmental temperatures: 15.6, 21.1, and 26.7 C. Shape of the specific sensible and latent heat curves were similar for the 15.6 and 21.1 C temperatures, but the sensible heat production at 15.6 C was about 12% greater than for 21.1 C for chickens weighing between 500 and 1000 g; the different increased for heavier chickens. Heat production curves for 26.7 C were markedly different from the other two temperatures. Specific sensible heat at 26.7 C was 2.8 cal/hr (g) and was independent of body weight over the range 500 to 1800 g. The data were compared to those published since 1969 to determine if increased growth rates have affected heat production data. Results indicate no discernible effect for cool temperatures, but for warm temperatures it appears that increased growth rates may be accompanied by an approximately proportional increase in specific sensible heat production.

Animals↗
PubMed1982

Effect of atmospheric ammonia on laying hen performance.

In periods of extremely cold weather, energy conservation in a pit-type laying house usually results in a restricted ventilation rate and an increase in air pollutants particularly ammonia. Results show that 200 ppm ammonia for 17 days causes a significant loss in percent egg production and the hens lose a significant amount of weight with a reduced feed intake. Although not satisfactory, it appears that lesser amounts of ammonia (100 ppm) can be tolerated for short periods without an immediate drastic loss in laying performance if a choice has to be made between frozen waterers and cold stress versus atmospheric ammonia in the laying house.

Ammonia↗
PubMed1982

Dietary energy requirements of broilers reared in low and moderate environmental temperatures. 1. Adjusting dietary energy to compensate for abnormal environmental temperatures.

Four trials were conducted to determine the feasibility of replacing fossil fuel energy with dietary energy to meet the 23- to 48-day-old broiler chicken's energy requirements during abnormal cold exposure. Sexed broilers were fed 3250 or 3500 kcal metabolizable energy (ME)/kg in a 21.1 C environment (a normal management situation), and 3250 or 3125 kal ME/kg in a 26.7 C environment. Body weights and feed utilizations increased when broilers were exposed to a 15.6 C environmental temperature and fed 3375 kcal ME/kg dietary energy as compared to feeding a 3250 kcal ME/kg dietary energy in the same environment. When broilers were reared in a 10.0 C environment, maximum body weights were not obtained by increasing the dietary energy from 3250 to 3500 kcal/kg dietary energy. Broiler males, fed 3250 kcal ME/kg and reared in either a 21.1 or a 26.7 C environment, were larger than males reared in 10.0 C environment. No significant differences were found in broiler female weights reared in a 10.0, 15.6, or 21.1 C environment and fed 3250 kcal ME/kg in each temperature regimen. Feed utilizations were the same broilers were reared in a 15.6 C environment and fed 3375 kcal ME/kg compared to broilers reared in a 21.1 C environment and fed 3250 kcal ME/kg. These results indicate that maximum performance of 23- to 48-day-old broilers may be achieved in a 15.6 C environment by feeding a high energy diet (3375 kcal/kg). Results also showed that dietary energy may replace fossil fuel energy that would normally be supplied in a 21.1 C environment.

Adipose Tissue↗
PubMed1982

Effects of dietary nutrient density on broiler performance at low and moderate environmental temperatures.

Three broiler finishing rations with calculated metabolizable energy values (ME) of 3175, 3250, and 3325 kcal/kg and constant lysine and sulfur-bearing amino acid: energy ratios were evaluated at two environmental temperatures. Broiler chickens were reared from 3 to 7 weeks in either an 18.3 or 26.7 C temperature. At the 18.3 C temperature, 7-week body weights increased linearly 3.1% as energy level increased from lowest to highest level. Feed:gain ratio decreased linearly 5.0% as energy level increased from lowest to highest. At the 26.7 C temperature, no significant differences were found in 7-week body weights due to energy level of the diet. Feed:gain ratio decreased 3.2% as energy level increased from lowest to highest, but the response was not linear. Energy intake increased as dietary energy was increased in the cool temperature; energy intake was less in the warm temperature and did not change appreciably as dietary energy changed. Because lysine and methionine plus cystine were tied to dietary energy by a fixed ratio, the pattern for intake of these amino acids was the same as for energy. It appears that the procedures used to formulate the diets do not give uniform results for the range of environmental temperatures and energy levels tested.

Animals↗
PubMed1980

Effect of carbon dioxide on broiler chicken performance.

Broiler chickens were exposed to 3,000, 6,000 and 12,000 ppm of CO2 for the 4-week brooding period, and their performance was compared to that of controls brooded where the CO2 level did not exceed 1,000 ppm. Exposure to 3,000 and 6,000 ppm did not significantly affect body weights at 4 or 7 weeks, but exposure to 12,000 ppm of CO2 depressed body weight at 4 weeks by about 60 g; the deficiency in weight persisted until 7 weeks of age. Feed conversions were not affected.

Animals↗
PubMed1978

Lysine requirement of broilers as influenced by environmental temperatures.

Two experiments were conducted to determine the influence of 15.6 and 29.4 degrees C. environmental temperatures on 2- to 4-week broiler lysine requirements. Weights for 4-week-old cockerels were maximum when either 1.10% dietary lysine in the 15.6 degrees C. environment or 1.00% dietary lysine in the 29.4 degrees C. environment were fed. Feed was used more efficiently by 4-week old cockerels fed either 1.10% dietary lysine in the 15.6 degrees C. environment or 0.95% dietary lysine in the 29.4 degrees C. environment. Plasma free lysine concentrations from 4-week-old cockerels increased as dietary lysine increased. Total plasma free amino acid concentrations from chicks grown in a 15.6 degrees C. environment were approximately 25% greater than from chicks grown at 29.4 degrees C. Total plasma free amino acids for 4-week-old cockerels peaked when 1.05% dietary lysine in the cool environment and 0.95% dietary lysine in the warm environment were fed.

Amino Acids↗