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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

The Effects of a Single Strain Bacillus subtilis DFM on pullet performance, laying hen performance, and egg quality when fed from day of hatch until 70 weeks

Samper, Jordyn Marie 18 August 2022 (has links)
Direct-fed microbials (DFM) are a method to increase bird performance and health when antibiotics are removed or limited in the diet. The objective of this experiment was to determine the effects of a single strain Bacillus subtilis DFM on pullet performance, layer performance, and egg quality when fed from day of hatch until 70 weeks of age. In total, 576 Hy-Line W-36 laying hen pullets were randomly divided between two treatments (Control and DFM) on day of hatch across 12 cages for each of the treatments and maintained on those respective treatments for 70-weeks. The DFM was added at a target dose of 300,000 cfu/kg of feed. At the end of the 17-week pullet phase, DFM fed pullets resulted in reduced feed intake, improved FCRm with both similar body weights (P = 0.98) and body composition (P > 0.05) to the control fed pullets. At 17 weeks, 72 birds were randomly selected from each treatment and moved to 12 laying hen cages. At the end of the 52-week laying hen phase, DFM-fed hens had significantly higher hen-day egg production (P = 0.02), but decreased egg weights. No differences were reported in egg mass or feed intake, but FCR was significantly improved (P = 0.02) on a per dozen eggs basis, and improved (P = 0.06) on a g/g basis by 7.1 points with DFM-fed hens having an FCR of 2.016 and control fed hens having and FCR of 2.087. Supplementation of diets with DFM resulted in a trend in egg specific gravity, but no differences were reported in shell breaking strength or shell weight. Overall, supplementation of the DFM lowered feed intake and improved FCR without affecting body composition in the pullet phase, and increased production and improved FCR during the egg laying phase. / Master of Science / Due to the decreased use of antibiotics across the poultry industry, producers and allied companies are developing new methods to increase bird health and performance when antibiotics are removed from or limited in the diet. One such method is through the use of "good" bacteria or technically called Direct-Fed Microbials (DFM). Direct-fed microbials are defined as live microorganisms that when fed, confer a health benefit to the host. The goals of this thesis were to determine the effects of a Bacillus subtilis based DFM on pullet performance, laying hen performance, and egg quality when fed from day of hatch until 70 weeks of age. In the pullet phase, DFM-fed pullets had reduced feed intake and improved feed conversion ratio (the ratio of feed intake to body weight gain), with no differences in body weights or body composition at the end of the 17-week growth period. In the laying phase, DFM fed hens had significantly improved egg production, but lighter eggs compared to the control fed hens. Addition of the DFM significantly improved feed conversion ratio per dozen eggs by 5.3 points and reduced feed conversion ratio on a g/g basis by 7.1 points in the 52-week laying phase. Small improvements were noted in specific gravity, but no differences were reported in shell weight or shell breaking strength. When fed from day of hatch until 70 weeks of age, the Bacillus subtilis DFM allowed the pullets to reduce their feed intake, but maintain body development for egg production resulting in an improved feed conversion ratio (FCR) in the growth phase before egg production and once hens initiated egg production resulted in smaller eggs, but increased egg production and FCR in laying hens with minimal differences in egg quality. Therefore, the DFM may be able to be used in place of growth promoting antibiotics to help support efficient protein production.
22

Vliv ustájení na parametry užitkovosti nosnic / Stabling influence on the performance parameters of laying hens

KECLÍKOVÁ, Magda January 2015 (has links)
The aim of the thesis was comparing production parameters of laying hens breeding in different housing systems at a production enterprise, it means in enriched cages and aviary. There is used the laying hybrid ISA Brown for production consumer eggs. The achievement during 13months' cycle shown that in each laying month except 1st laying month the higher hen-day egg production was fond out by hens in enriched cages. The hen-egg production per month was higher in enriched cages too. The higher mortality was demonstrated by hens in aviary during all laying months. Both housing systems reached the highest mortality in the 13th laying month. The hens in aviary had higher feed consumption per egg during all months. Higher daily feed consumption was assigned by the hens in the aviary in the 1st, 2nd and 3rd month and from the 9th to the 13th laying month. In other laying months the hens in enriched cages had higher daily feed consumption. Feed costs formed the highest entry of total costs.
23

Vliv technologie ustájení nosnic na produkci konzumních vajec. / The impact of layer housing technology on commercial egg production.

TOLKNER, Martin January 2014 (has links)
In this thesis the selected enterprise indicators of laying were analyzed in terms of the impact of a hen housing system. For commercial egg production in the enterprise the laying hybrid Lohmann brown-LITE hen has been used since 2011. A total of 16 laying turns were included for the observation during the period of 20112014. Due to the sufficient number of data a nine-month laying batch has been chosen. The highest average number of eggs laid by one hen for the observation period was achieved in the Profit-Tier Layer Cage System by Big Dutchman (257.0 pcs.). In the Laying battery Cage System by Kovobel the number of eggs was by 1.3 pcs lower (255.7 pcs). The lowest number of eggs was set down for laying hens kept in a cage free systems (249.2 pcs). It was 7,8 pcs and 6,5 pcs lower respectively than with laying hens housed in the cage systems by Big Dutchman and Kovobel. The highest average intensity of laying for 9-month laying period was found in the cage system by Big Dutchman (93.9%). In the cage system by Kovobel company it was 1.0 % lower (92.9 %). The intensity of laying at a cage free system amounted to 89.2 % pcs. It was 4.7 % and 3.7% respectively lower than when housed in the cage systems by Big Dutchman and Kovobel. For laying hens kept in a cage system the average consumption per hen in a day, for the observed period, was found out to be lower 117.6 g for the cage system by Big Dutchman company and 117.4 g for Kovobel. The highest average feed consumption showed 121.5 g with laying hens kept in a cage free system. The average mortality of laying hens during the observed period was 0.64 %.
24

Circuit and Behavioral Basis of Egg-Laying Site Selection in Drosophila melanogaster

Zhu, Edward January 2015 (has links)
<p>One of the outstanding goals of neuroscience is to understand how neural circuits are assembled to produce context appropriate behavior. In an ever changing environment, it is critical for animals to be able to flexibly respond to different stimuli to optimize their behavioral responses accordingly. Oviposition, or the process of choosing where to lay eggs, is an important behavior for egg-laying animals, yet the neural mechanisms of this behavior are still not completely understood. Here, we use the genetically tractable organism, Drosophila melanogaster, to investigate how the brain decides which substrates are best for egg deposition. We show that flies prefer to lay eggs away from UV light and that induction egg-laying correlates with increased movement away from UV. Both egg-laying and movement aversion of UV are mediated through R7 photoreceptors, but only movement aversion is mediated through Dm8 amacrine neurons. We then identify octopaminergic neurons as being potential modulators of egg-laying output. Collectively, this work reveals new insights into the neural mechanisms that govern Drosophila egg-laying behavior.</p> / Dissertation
25

Diferentes densidades de gaiola e suas implicações no comportamento de galinhas poedeiras e na qualidade dos ovos produzidos / Different cage densities and their implications on the behavior of laying hens and the quality of eggs

Cabrelon, Maria Amelia Flandres 26 January 2016 (has links)
Objetivou-se com esta pesquisa avaliar o efeito de diferentes densidades de galinhas poedeiras alojadas em gaiolas convencionais (50x45x40 cm) nos índices produtivos, na viabilidade, qualidade dos ovos e comportamento das aves. A pesquisa foi realizada na cidade de Bastos (SP) com duração de 18 semanas. Foram utilizadas 500 aves, da linhagem ISA Brown, distribuídas em 5 tratamentos com 25 repetições cada. Os tratamentos foram: tratamento 1: 6 aves/ gaiola (375,0 cm²), tratamento 2: 5 aves/gaiola (450,0 cm²); tratamento 3: 4 aves/gaiola (562,5 cm²); tratamento 4: 3 aves/ gaiola (750,0 cm²) e tratamento 5: 2 aves/gaiola (1.125,0 cm²). Adotou-se o delineamento inteiramente aleatorizado, este contendo cinco tratamentos e 25 repetições. De acordo com os resultados, verificou-se que o tratamento 1 apresentou as menores médias percentuais de produção quando relacionado aos demais tratamentos, diferindo-se estatisticamente. A viabilidade e qualidade dos ovos, não apresentaram diferença estatística entre os tratamentos. Já com relação ao comportamento das aves foi possível observar que o tratamento 5 (menor densidade) foi o que expressou diferentes comportamentos e diferiu-se estatisticamente dos demais. Observou-se também que, quanto à atividade, o tratamento 5 passou menor parte do tempo \"parado\". De acordo com esses resultados, conclui-se que com o aumento da densidade, ocorreu uma significativa redução na produção e na viabilidade, porém, quanto a qualidade dos ovos, não sofreu influência significativa, em relação aos comportamentos das aves, observouse que os animais expressaram melhor o seu comportamento natural quando estavam em menor densidade, ou seja, maior espaço. / The objective of this research was to evaluate the effect of different densities of laying hens housed in conventional cages (50x45x40 cm) in production rates, viability, quality of eggs and bird behavior. The survey was conducted in the city of Bastos (SP) lasting 18 weeks. They were used 500 birds, ISA Brown hens, distributed in 5 treatments with 25 repetitions each. The treatments were: Treatment 1: 6 / Bird Cage (375.0 cm²), treatment 2: 5 birds / cage (450.0 cm²); treatment 3: 4 birds / cage (562.5 cm²); Treatment 4: 3 birds / cage (750.0 cm²) and treatment 5: 2 / Bird Cage (1125.0 cm²). Adopted a completely randomized design, this containing five treatments and 25 repetitions. According to the results, it was found that the treatment 1 had the lowest average percentage of production when related to other treatments, differing statistically. The viability and quality of eggs, there was no statistical difference between treatments. In relation to the behavior of birds was observed that the treatment 5 (lower density) was expressed that the different behaviors and differed statistically from the others. It was also observed that, as the activity, treatment 5 spent less of their time \"stopped\". According to these results, we conclude that with the consolidation of the cages, it was noticeable that the production and mortality has a significant worsening, as the quality of eggs, there was no influence of the different densities of the conduct of the birds, it is observed that the animals best express their natural behavior when they are in lower density, or larger space.
26

Improving the Effectiveness of Laying Hens for Use in Value-Added Egg Production.

Nain, Sandeep 06 1900 (has links)
A series of experiments were conducted to explore factors affecting transfer of value-added ingredients from the diet to table eggs, with the goal of contributing to improvements in the enrichment process. Flaxseed-based ω-3 PUFA enrichment did not reduce lutein enrichment. The combine enrichment of lutein and ω-3 PUFA had decresed lipid oxidation potential. Also, when fed a ω-3 PUFA diet, birds scored as energetic Efficient had longer and wider villi, resulting in greater absorptive surface area/villi than Non-efficient hens. However, histomorphological differences did not affect transfer of ω-3 PUFA from diet to egg. Finally, birds fed graded levels of ω-3 PUFA to characterize change in lipid profile of egg and blood plasma in time reached a plateau in total ω-3 PUFA/egg in 5.9 to 6.6d, with High birds reaching the target of 300 mg/egg in 5d. Egg enrichment can be modulated by changes to the hen diet. / Animal Science
27

Evaluation of guar meal as a source of prebiotic galactomannans for laying hens

Zhang, Cheng 01 November 2005 (has links)
Four experiments were conducted to evaluate guar meal as a source of prebiotic galactomannans for laying hens. In the 1st experiment, late phase laying hens were fed diets with 0, 5, 10% guar meal (GM) for 56 days or 15% GM for 28 days then switched to the 0% GM diet for the final 28 days. In the 2nd experiment, young pullets were fed guar germ (GG) or GM at 0, 2.5 or 5% for 20 weeks. In the 1st and 2nd experiments, egg production and feed consumption were not affected by feeding up to 5% guar by-products whereas feed efficiency was decreased by guar feeding. Feeding of GG or GM did not affect egg weight or shell quality, but decreased the egg yolk color and Haugh units. Guar increased absolute and relative liver weight, but did not affect the weights of the pancreas, spleen, or the incidence of fatty liver or liver hemorrhage. Feeding 10% GM depressed feed consumption and increased body weight loss. Feeding 15% GM severely depressed egg production followed by a recovery of production after returning to 0% GM feeding. In the 3rd and 4th experiments, late phase laying hens were induced to molt by feed withdrawal (FW) or feeding 15 or 20% GM with or without β-mannanase (Hemicell??). All hens except those fed 15% GM with enzyme obtained a complete cessation of lay in 10 days. Compared to FW birds, hens fed GM had lower body weight reduction and mortality, while hens fed 20% GM with enzyme had higher post-molt egg production. Salmonella enteritidis (SE) present in 6 organs (crop, liver, spleen, ovary, oviduct and cecum), and SE in cecal contents were significantly reduced by 20% GM feeding with and without enzyme. The results showed that GG or GM can be safely fed to laying hens up to 5% without adverse effects on performance. An alternative molting method employing 20% GM with or without β-mannanase is preferable to FW because GM feeding results in a complete molt and decreases mortality, as well as enhances the resistance to SE of molted hens.
28

Barley silage effects on poultry behaviour

Johannson, Sarah G. 28 April 2008
A series of trials were conducted to determine the effect of feeding barley silage to laying hens and broiler breeder pullets on performance, stress and behaviour. In the first study, two trials were conducted each with 20 hens and 2 roosters (n=176) randomly assigned to one of 8 community cages. The birds in 4 cages were provided with a nutritionally balanced soy/wheatbased laying hen diet ad libitum, whereas the birds in another 4 cages were given free access to barley silage in addition to the regular laying hen diet. In both trials, the control birds consumed more feed (P < 0.05) than the birds given barley silage. Birds fed barley silage had significantly decreased (P < 0.05) aggressive and feather pecking behaviours as well as time spent in their nest boxes at different ages. Time spent drinking, resting, preening and eating a large particle calcium source was similar between the two treatments. No treatment effects (P > 0.05) were found in regards to egg quality, egg production and bird weights at various ages; however yolk colour was darker by silage treatment in each trial. At the end of each trial, the feather score was improved in silage-fed birds compared to the control birds. It was concluded that feeding barley silage as a supplement to laying hens can improve their welfare without negatively affecting the egg production and egg quality. <p>A second study was conducted to determine the effect of feeding barley silage on body weight, stereotypic behaviour, stress and fear on broiler breeder pullets during the brooding and rearing periods. The 3 week old broiler breeder pullets (n=180) were randomly allocated into 12 straw litter floor pens having 15 birds per pen. The birds in 6 pens were provided with a nutritionally balanced corn/oat-soybean/canola meal-based broiler breeder diet at recommended restricted levels, whereas the birds in another 6 pens were given free access to barley silage in addition to a regular broiler breeder diet. Total DM intake was significantly higher (P < 0.05) for silage-fed birds compared to their control counterparts without affecting mean body weights. Dietary treatment had no significant effect on bird behaviour with the exception of object pecking behaviour which was reduced with silage feeding. Aggressive and gentle feather pecking behaviour was consistently numerically higher in the control birds than the silage-fed birds, although not significantly. Age affected many of the behaviours recorded in this study. Silage feeding had no significant effect on heterophil to lymphocyte ratios and tonic immobility values indicating that birds in both treatments were not very stressed or fearful. It was concluded that feeding barley silage to broiler breeder pullets has potential to aid in improving their welfare.
29

Evaluation of Yeast Cell Wall on Early Production Laying Hen Performance

Hashim, Mohammed Malik Hashim 1981- 14 March 2013 (has links)
he influence of two levels of yeast cell wall on phase one laying hen performance was investigated in this study. A total of 75 Lohmann W-36 replacement pullets, 17-weeks-old, were distributed among 75 laying hen cages (1 bird per pen). A total of 3 treatments were sequentially assigned to pens and each treatment had 25 replicates. Feeds were prepared according to the management guide for those birds and a single basal diet was divided into three treatments. First was the control basal diet only with no feed additives. The second was the basal diet supplemented with 250 ppm of yeast cell wall (YCW 250) and the third treatment was the basal diet supplemented with 500 ppm of yeast cell wall (YCW 500). Individual birds per cage served as the experimental unit for this study. Feed and water were offered ad libitum. Data were collected when birds were 21 weeks old and hen day egg production was > 90%. Treatment YCW 250 resulted in significantly higher egg weight than the control and YCW 500 treatment in the first and second production period and was higher than YCW 500 in the third and fourth production period. Feed consumed per dozen eggs was significantly lower in treatment YCW 500 versus treatment YCW 250, but not significantly lower than the control for the first production period and all treatments were not different from each other for the rest of the study. Average feed consumed per bird per day, and monthly cumulative egg production was not different between treatments. Period feed conversion ratios were lower for the second and fourth period (P = 0.15 and 0.18 respectively). There was no treatment effect on interior egg quality except for yolk color for the YCW 500 treatment in the fourth period which had significantly higher Roche color scores than the YCW 250 treatment. Specific gravity, egg shell thickness, egg shell weight, and percent shell weight were significantly higher in hens fed YCW 500 versus YCW 250. Egg shell breaking force was significantly higher in hens fed YCW 250 versus the control group. Overall, feeding a diet supplemented with yeast cell wall improved laying hen performance and 250 ppm YCW had the most significant influences, particularly with respect to increasing egg weight in early production laying hens.
30

Barley silage effects on poultry behaviour

Johannson, Sarah G. 28 April 2008 (has links)
A series of trials were conducted to determine the effect of feeding barley silage to laying hens and broiler breeder pullets on performance, stress and behaviour. In the first study, two trials were conducted each with 20 hens and 2 roosters (n=176) randomly assigned to one of 8 community cages. The birds in 4 cages were provided with a nutritionally balanced soy/wheatbased laying hen diet ad libitum, whereas the birds in another 4 cages were given free access to barley silage in addition to the regular laying hen diet. In both trials, the control birds consumed more feed (P < 0.05) than the birds given barley silage. Birds fed barley silage had significantly decreased (P < 0.05) aggressive and feather pecking behaviours as well as time spent in their nest boxes at different ages. Time spent drinking, resting, preening and eating a large particle calcium source was similar between the two treatments. No treatment effects (P > 0.05) were found in regards to egg quality, egg production and bird weights at various ages; however yolk colour was darker by silage treatment in each trial. At the end of each trial, the feather score was improved in silage-fed birds compared to the control birds. It was concluded that feeding barley silage as a supplement to laying hens can improve their welfare without negatively affecting the egg production and egg quality. <p>A second study was conducted to determine the effect of feeding barley silage on body weight, stereotypic behaviour, stress and fear on broiler breeder pullets during the brooding and rearing periods. The 3 week old broiler breeder pullets (n=180) were randomly allocated into 12 straw litter floor pens having 15 birds per pen. The birds in 6 pens were provided with a nutritionally balanced corn/oat-soybean/canola meal-based broiler breeder diet at recommended restricted levels, whereas the birds in another 6 pens were given free access to barley silage in addition to a regular broiler breeder diet. Total DM intake was significantly higher (P < 0.05) for silage-fed birds compared to their control counterparts without affecting mean body weights. Dietary treatment had no significant effect on bird behaviour with the exception of object pecking behaviour which was reduced with silage feeding. Aggressive and gentle feather pecking behaviour was consistently numerically higher in the control birds than the silage-fed birds, although not significantly. Age affected many of the behaviours recorded in this study. Silage feeding had no significant effect on heterophil to lymphocyte ratios and tonic immobility values indicating that birds in both treatments were not very stressed or fearful. It was concluded that feeding barley silage to broiler breeder pullets has potential to aid in improving their welfare.

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