Introduction: In the Northern region of the Northern Province, there is an increase in the number of small-scale and semi-commercial farms in all sectors of agriculture. This includes the production of grains, vegetables, fruits and livestock. Broiler production seemed to be a much-preferred alternative of development in community based projects and emerging farmers have shown keen interest. This is because broiler production requires less space than ruminants and is ready for human consumption within a very short period of time. Poultry production provides a constant source of income and protein with a big customer demand. By the year 2000, broiler production is expected to reach 4000 million and 7.5 million tons of poultry feeds in the world. Many countries have initiated programs aimed at improving small-scale poultry as a means of helping to bring socio- economic benefits to rural communities (Panda, 1989). In order to feed the ever rising population of 4.9 million in the Northern Province (1996 Census), there must be an increase in the production of broilers as a primary source of top quality animal protein. With the high unemployment rate (46%) in the Northern Province, self- employment projects are needed which comply with agro- processing. More than 90 community projects based on poultry production in the Northern region of the Northern Province had been established in order to reduce the high rate of unemployment. Today more people have engaged themselves in community projects especially in poultry production than ever before. Some of the constrains of broiler production at both small-scale and semi-commercial farming condition includes inadequate ventilation system. Lack of suitable health care facilities and frequently the absence of efficient marketing structures form part of the obstacles to the rapid development of poultry production. Feed costs which remain the highest input cost in the production of broilers represent between 60 to 70% or more of the total costs of broiler productions (Benyi and Habi, 1998). Lack of management skills and training for small and semi-commercial farmers makes it difficult to obtain optimum performance. The objective of this study is to evaluate the performance of broilers as influenced by environmental factors under small.

Commercial broiler chickens were reared as combined sexes at floor space areas of 0.6, 0.7, 0.8, 0.9 and 1.0 ft.2 per bird to ten weeks of age. There was no significant difference in the mean body weights at nine weeks of age. At ten weeks of age, there was no significant difference in the mean body weights of the birds reared at 0.7, 0.8, 0.9 and 1.0 ft.² per bird, while the floor area of 0.6 ft.² per bird produced significantly lighter birds than did 1.0 ft.² Mortality was not affected by bird density, whereas the percentage of breast blisters increased with increasing density. Broiler production costs and various combinations of feed and meat prices were used in models to determine the age at which maximum annual net returns per square foot of floor area occurred. Assuming that the weekly mean body weights were the same for birds grown at 0.7 and 1.0 ft.² per bird floor area, maximum net returns were obtained by marketing at nine or ten weeks of age depending on feed and meat prices. The effect on net returns of marketing one week earlier or later than at the age of greatest net returns was examined. When it was assumed that the number of lots per year was limited to 4.33 i.e. a twelve week replacement program, annual maximum net returns were found to occur at a market age of at least ten weeks. When the number of lots marketed was not assumed to be limited, annual maximum returns also occurred, with few exceptions, at least at ten weeks of age. / Land and Food Systems, Faculty of / Graduate

An experiment was designed to test the hypothesis that enthalpy could be used as an indicator of the suitability of the environment for growing poultry. Growth-rates and body weights of the birds were used as a measure of their performance under different enthalpy conditions. The experiment tested three enthalpy treatments, ranging from 29.3 to 33.3 BTU/lb of air, each treatment being replicated three times. Male University of British Columbia New Hampshire chickens from nine hatches (120 birds per hatch) were used. They were grown from hatch to seven weeks of age in three groups. Two of the groups were raised from hatch to three weeks of age in controlled environment brooders. The third group was raised in a non-controlled environment in a floor pen, and used as a check or control group. The results of the analyses indicated that further study would be necessary before enthalpies in the range studied could be used to predict environmental conditions for poultry. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate

Corrigenda inserted behind title page. Bibliography: leaves 275-306. The pattern of body growth and intestinal development of an Australian strain of broiler chicken, the Steggles x Ross (F1) in response to different diets was studied. Five experiments were designed to examine the pattern of growth and mechanisms involved. In four other experiments, the mechanisms underlying the gross response of the broiler chicks to dietary ingredients, anti-nutritive factors and growth enhancers were examined. Results indicated that a rapid development of the small intestine preceded significant overall body growth. Body growth would, however, depend more on the various physiological events such as those related to mucosal growth and renewal, digestive enzyme function, and nutrient transport. Some of the differences observed in productivity of broiler chickens on different diets were traced to events at the intestinal level.

Thesis (M.Sc. (Agric.)(Animal and Wildlife Sciences)) -- University of Pretoria, 2009. / Abstract in English. Includes bibliographical references.

Two growth trials were designed to measure the effects of: (1) dietary Virginiamycin (0 or 16.5 mg/kg) and added fat (0 or 4%), and (2) Virginiamycin (0 or 16.5 mg/kg) and dietary lysine levels (low, NRC, high) individually, and in combination on broiler performance. A third trial investigated the relationship of plasma glucose, triglyceride and phospholipid concentrations with degree of fatness/leanness in genetically lean and fat broiler chickens. A combination of supplemental fat and Virginiamycin increased protein and decreased fat content of the dressed carcass. Virginiamycin supplementation overcame the growth depression of a low lysine diet by increasing feed intake. In the low lysine diet, Virginiamycin supplementation reduced abdominal fat deposition in females and increased carcass yield in males. Carcass protein content was increased by feeding the NRC-recommended level of lysine or by Virginiamycin supplementation. (Abstract shortened by UMI.)

Corrigenda inserted behind title page. / Bibliography: leaves 275-306. / xxxv, 306 leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The pattern of body growth and intestinal development of an Australian strain of broiler chicken, the Steggles x Ross (F1) in response to different diets was studied. Five experiments were designed to examine the pattern of growth and mechanisms involved. In four other experiments, the mechanisms underlying the gross response of the broiler chicks to dietary ingredients, anti-nutritive factors and growth enhancers were examined. Results indicated that a rapid development of the small intestine preceded significant overall body growth. Body growth would, however, depend more on the various physiological events such as those related to mucosal growth and renewal, digestive enzyme function, and nutrient transport. Some of the differences observed in productivity of broiler chickens on different diets were traced to events at the intestinal level. / Thesis (Ph.D.)--University of Adelaide, Dept. of Animal Sciences, 1999

No description available.

This study was conducted to examine the potential of plastic slats as flooring material for maintenance of broiler breeders. Although plastic slats are more expensive than wood slats, plastic slats are more durable and easier to clean. Wood and plastic slats were tested as full and partial flooring to determine the ideal proportion of slats for broiler breeder floors. Space allotment was 2040 cm²/bird on all floor treatments. . Arbor Acres broiler breeders, one of the more common strains in British Columbia, were raised to 58 weeks of age to monitor the influence of slat material and slat coverage on egg production and progeny growth over one production cycle. Since the pens were not set up to determine the number of eggs lost through slats, "egg production" values were actually egg recovery values. Over-all egg recovery was significantly higher on partial wood (PWS) and partial plastic slats (PPS) than on either of the full slat treatments. Breeders on full wood slats (FWS) had higher over-all egg production than those on full plastic slats (FPS). Differences were significant for three biweekly periods, but slats did not influence the over-all incidence of floor eggs and cracked floor eggs. The incidence of cracked nest eggs was significantly higher in FWS and FPS than in PWS and PPS pens during four lay periods and overall. The proportion of non-cracked nest eggs, which was taken as an approximation of the proportion of settable eggs, was higher for partial slat pens than full slat pens, and FWS pens had a higher proportion of non-cracked nest eggs than FPS pens. To monitor fertility and hatchability, eggs were incubated at 37, 42, 46, 50 and 56 weeks of breeder age. Fertility, hatchability of total eggs set and hatchability of fertile eggs was not affected by type of slats. Progeny from the hatch at 37, 46 and 56 week of breeder age were grown in Petersime battery cages to three weeks of age. The progeny of breeders on FPS had lower first week weight gain than the other progeny groups due to moisture loss when 7 FPS progeny were lost during the second growth trial. Weekly and over-all feed conversion of progeny was not affected by types of slats used by parents. The 56th week progeny were grown in Petersime battery cages to market age (six weeks). PWS and FPS progeny had higher third week weight gain than PPS progeny. During the sixth week, FWS and PWS progeny had higher weight gain than FPS and PPS progeny. The sixth week feed conversion of FPS progeny was higher than that of the other three progeny groups. No other differences were seen. As long as slats were used as partial flooring, there were no differences in egg production on wood or plastic slats. The proportion of "settable" eggs, fertility, and hatchability of eggs of plastic slat breeders were comparable with that of wood slat breeders regardless of slat coverage. There were significant differences in the 3-week growth of 37th, 46th and 56th week progeny and the 6-week growth of 56th week progeny on the different slat types, but the differences were not due to slat treatments. There was no interaction between breeder age and slat material, therefore the influence of slat material on egg production and progeny growth did not vary with breeder age. Although egg recovery and the number of settable eggs were lower for FPS breeders, breeders on plastic slats performed as well as those on wood slats in the present study. / Land and Food Systems, Faculty of / Graduate

Seven experiments were carried out to investigate the involvement of carbohydrate and lipid metabolism on the incidence of Sudden Death Syndrome (SDS) in broiler chickens. Hepatic arachidonate level decreased after 1 h postmortem. The decreased level of hepatic arachidonate previously observed in SDS birds was, therefore, associated with the post-mortem aging. Broiler chickens fed diets high in glucose monohydrate (cerelose) were more susceptible to SDS mortality than broilers fed diets high in corn starch or corn-soy. Feeding broilers a high cerelose diet increased the levels of plasma calcium, total protein, triacylglycerol, and uric acid compared to broilers fed corn starch diet. Broilers fed cerelose diet also showed the higher incidence of leg abnormality than broilers fed corn starch or corn-soy diets. Daily intraperitoneal injection with 0.25 ml of L(+) lactic acid solution (100 mg lactic acid/ml) to broilers over a 7-d period failed to reproduce the SDS incidence, whereas intravenous injection of 40% lactic acid solution (200 mg lactic acid/kg body weight) resulted in 100% incidence of SDS-type mortality. No SDS-type mortality was observed with the intravenous injection of 40% sodium lactate solution (200 mg sodium lactate/kg body weight). Disturbance of physiological acid-base balance might be a factor in the SDS-type mortality. Suboptimal thiamin level in broilers fed cerelose diets was observed. Thiamin supplementation to cerelose diet improved the thiamin status of the broilers. Mortality due to SDS was decreased when thiamin hydrochloride was supplemented to cerelose diet at the level of 0.6 and 2.8 mg thiamin hydrochloride/kg diet, respectively. Thiamin supplementation, however, did not change the liver pyruvate dehydrogenase activity and the proportion of pyruvate dehydrogenase in the active form. Disturbance of acid-base balance was postulated to be associated with the incidence of SDS. Other genetic, nutritional, and environmental factors are likely to modify the incidence by affecting the acid-base status of the chicken. / Graduation date: 1993