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The Virginia Stocked-Trout Program: An Evaluation of Anglers and Their CatchHyman, Amanda Ashley 19 January 2016 (has links)
Despite the long history of stocking trout and the popularity of stocked-trout fishing in Virginia, no study has investigated the use of the program nor attempted to describe anglers actively seeking stocked trout. Agencies have stocked trout in Virginia since the 1920s and today, Virginia Department of Game and Inland Fisheries (VDGIF) stocks the majority of the fish in the state, stocking over 1 million catchable-sized trout on over 180 waters. Given the expansive effort of VDGIF and the popularity of the program, VDGIF desired to understand how anglers utilize their program and who actively fishes for stocked trout. My objectives were 1) to assess catch, harvest, effort, and return-to-creel rates of stocked trout on various fishery and water body types, across seasons and number of days post-stocking in stocked waters in western Virginia, 2) to identify market segments of anglers seeking stocked trout based upon their demographic characteristics, motivations, and degree of specialization, 3) to compare satisfaction and management preferences of the market segments of anglers seeking stocked trout in Virginia and 4) to recommend stocking and management strategies that best meet the desires of stocked-trout anglers in Virginia and that produce managerially desired catch rates to the Virginia Department of Game and Inland Fisheries.
I conducted on-site surveys on 17 stocked-trout waters across Virginia. Most anglers reported high levels of satisfaction with their fishing experience that day and with the program in the last 12 months. The majority of anglers caught something that day. Anglers had diverse fishing and management preferences.
Stocking density did not affect catch rate on lakes nor streams. Time following a stocking event did influence catch rate and effort; anglers caught fish the quickest on the day of stocking, but catch rate remained near 1 trout per angler-hr and did not significantly differ from the day after stocking to 30 days after stocking. Catch rate positively correlated with angler satisfaction, yet the majority of the anglers were highly satisfied, even if they did not catch any fish.
We identified four groups of anglers: casual anglers, consumptive-experienced anglers, avid anglers, and specialists. Social investment, experience, and fishery resource use varied among the four groups. The four groups also had differing motivations for fishing, fishing preferences, management preferences, and levels of satisfaction.
Multinomial logistic regressions showed that specialization, age, catch rate, importance an angler places on catching something, and waterbody type contributed to the best model for predicting angler satisfaction. Anglers on streams typically expressed greater satisfaction than anglers on lakes. Angler satisfaction negatively correlated with the importance an angler placed on catching something. / Master of Science
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The Virginia Stocked Trout Program: An Evaluation of Current and Former AnglersDiCenzo, Victor James 21 April 2016 (has links)
Trout anglers comprise about 20% of all anglers in Virginia and expended > 1-million angler-days in pursuit of Virginia trout. Stocked trout account for approximately 80% of the trout angling effort in Virginia (O'Neill 2001) through a program managed by the Virginia Department of Game and Inland Fisheries (VDGIF). Each year, the VDGIF stocks > 1-million catchable-sized trout in about 180 waters in Virginia.
Despite the popularity of stocked trout fishing in Virginia, several factors potentially threaten the future of the stocked trout program in Virginia. First, previous surveys indicate that stocked trout anglers are less satisfied with their fishing experiences in Virginia than other species specialists. Additionally, the sale of stocked trout fishing licenses declined 31% between 2006 and 2013. Revenue generated from the sale of trout licenses is a significant source of income that helps fund the stocked trout program.
Given the popularity of stocked trout fishing in Virginia and the considerable effort of VDGIF in managing the stocked trout program, my research objectives were to 1) identify homogenous angler groups seeking stocked trout in Virginia, 2) compare motivations, satisfaction, and preferences of stocked trout anglers in Virginia, and 3) examine the extent to which prior satisfaction and constraints relate to future participation.
To address objectives 1 and 2, I administered a mail survey of 5,400 licensed trout anglers in Virginia. Using cluster analysis, I identified four distinct groups of stocked trout anglers: traditional anglers, generalists, occasional specialists, and specialists. Traditional anglers constituted the largest group, comprised of those who fished with bait, harvested the stocked trout they caught, fished more frequently than other groups, had low centrality, and invested less money in trout fishing than did other groups. Generalists included those who took fishing-related vacations, fished with a variety of terminal tackle, harvested their catch, and demonstrated low invest little in fishing for stocked trout. Occasional specialists fished infrequently, had low centrality, invested little money in fishing, fished with lures and flies, and released the stocked trout they caught. Specialists had high centrality and investment, fished with flies, and almost always released the stocked trout they caught.
Psychological and natural-setting attributes were stronger motives to fish for stocked trout than were fishery and social motives. Anglers rated catching fish as being more important than keeping fish to eat. Overall, anglers were satisfied only somewhat with stocked trout fishing in Virginia. However, anglers rated satisfaction higher with activity-general characteristics, such as the setting and relaxing, than they did activity-specific factors, such as number or size of fish caught.
Results of stated preference choice models indicated that anglers preferred unannounced stockings rather than stockings announced in advance. Furthermore, anglers preferred stocking of streams rather than lakes, stocking taking place during the spring, and catching six 10-inch trout rather than fewer, larger trout. Compared to weekday stockings, anglers did not show a preference for weekend stockings, despite comments made at public meetings suggesting that many anglers preferred weekend stockings. Although four specialization levels exist for Virginia's stocked trout anglers, choice models suggest that preferences coalesced into only two groups: preferences of specialists differed from those of traditional anglers, generalists, and occasional specialists. When compared to the status quo fishing trip, traditionalists, generalists, and occasional specialists preferred a prior announced stocking, whereas specialists preferred a delayed announcement and catching fewer, but larger, trout.
To address the third objective, I surveyed 1,100 lapsed trout anglers (individuals who had purchased licenses twice between September 1, 2011, and August 31, 2013, but did not purchase one between September 1, 2013, and August 31, 2014). I found that anglers who placed high importance on non-catch-related factors (e.g., being outdoors, enjoying a relaxing experience, experiencing a natural setting) were more likely to fish for stocked trout again in the future. Constraints did not mediate the effect of prior satisfaction on future participation. However, structural constraints were related positively to future participation, suggesting that individuals who had more time and family commitments were more likely to negotiate those constraints and resume participation in the future. / Ph. D.
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Effects of Starvation and Time at Stocking on Survival of Stocked Rainbow Trout, Salmo gairdneriBricker, Marlin John 01 May 1970 (has links)
Investigations of effects of starvation and time at stocking on the survival of catchable rainbow trout in two areas of Mammoth Creek in Dixie National Forest, Utah, were conducted from May 24 to December 6, 1969. Fish were starved for 6 days and 1 day and stocked in the morning (5:40-7:00 a.m.) and in the afternoon (1:45-5:30 p.m.). Out of 7,000 tagged fish stocked, 4,751 tags were returned by fishermen. The 6-day starved fish, stocked in the morning returned to the creel in highest numbers (1,240); followed by 1-day starved, afternoon-stocked fish (1,194); 6-day starved, afternoon-stocked fish (1,163); and 1-day starved, morning-stocked fish (1,154). For the entire stream, the main effects of starvation and time at stocking were not significant at the 10 percent level, but their interaction was significant at the 1 percent level.
In the upper area, however, both 6-day starved lots returned to the creel in greater numbers (692) than the 1-day starved lots (643), and the main effect of starvation was significant at the 1 percent level in addition to the interaction being significant at the 5 percent level.
About 81 percent of the tags returned were from fish caught in the sections stocked. One percent of the tags were from fish that moved upstream and 18 percent from fish that moved approximately 3 miles or less downstream. No consistent downstream movement patterns were related to either starvation or time at stocking.
One week after the fishing season, 68 percent of all (19) tagged fish captured by electrofishing were 6-day starved fish, but this difference was not significant at the 10 percent level.
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Effects of Stocked Trout, Native Small-bodied Fish, and Winter Surface Aeration on Zooplankton in Small Boreal Foothills LakesHolmes, Teslin G. Unknown Date
No description available.
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Estudo da produção de gases pela digestibilidade in vitro do capim-Marandu [Brachiaria brizantha (Hochst ex A. Rich) Stapf], submetido a intensidades de pastejo / Study of gas production by in vitro digestibility Marandu palisadegrass [Brachiaria brizantha (Hochst ex A. Rich) Stapf], submitted to grazing intensitiesMarchesin, Wilson Aparecido 04 March 2010 (has links)
A presente pesquisa teve como objetivo analisar a produção de gases pela digestão in vitro do capim-Marandu [(Brachiaria brizantha (Hochst ex A. RICH) STAPF], quando submetido a quatro intensidades de pastejo, representadas pelas ofertas de forragem (OF) 5, 10 15 e 20% (kg de MSV/100 kg de peso animal/dia). O experimento foi realizado na Faculdade de Zootecnia e Engenharia de Alimentos - FZEA/USP, no município de Pirassununga/SP, Numa pastagem formada com Brachiaria brizantha. O delineamento experimental foi em blocos completos casualizados com 4 repetições. A área de 25,2 ha foi dividida em 16 unidades experimentais de 1,575 ha, subdivididas em 5 piquetes de 3150 m2, a fim de permitir um ciclo de pastejo de 35 dias, (sendo sete dias de ocupação e 28 dias de descanso). Os animais utilizados foram bovinos da raça Nelore (Bos taurus indicus L.) com peso médio inicial de 250 kg e aproximadamente 15 meses de idade. Para a técnica de produção de gases, os ensaios foram realizados de acordo com a técnica semi-automática. Os dados acumulativos da produção de gases foram gerados usando um transdutor de pressão e um \"data logger\" (PDL800, LANA/CENA/USP, Piracicaba/SP, Brazil). O substrato foi utilizado em triplicata com líquido ruminal de bovinos como inoculo. Três fêmeas bovinas fistuladas adultas da raça holandesa foram utilizadas como doadoras de inoculo. No preparo do inoculo utilizou-se 50% da fase líquida e 50% da fase sólida do conteúdo ruminal. As medições de gases foram realizadas às 6, 12, 18 e 24 horas após a inoculação. Foram realizadas as determinações de Ácidos Graxos Voláteis (acético, propiônico e butírico),por cromatografia gasosa. A degradabilidade da material seca in vitro foi determinada após 24 horas, juntamente com o fator de partição (FP). As amostras que foram utilizadas como substrato durante os ensaios laboratoriais foram colhidas durante seis ciclos de pastejo durante o ano de 2004, mais especificamente janeiro, fevereiro, março, maio, julho e agosto. Para as estações do ano (EA), os ciclos dos meses de janeiro e fevereiro foram designados como verão, os ciclos dos meses de março e maio como outono e os ciclos dos meses de julho e agosto como inverno. Um comportamento linear foi observado para os valores de Produção total de gases, Matéria Orgânica Digestível (MOD) e Matéria Seca Digestível (MSD) e os coeficientes de determinação obtidos foram 0,96, 0,94, 0,81 respectivamente. O volume de metano em mL/g de MSD e MOD produzido durante a fermentação foi semelhante, considerando as OF, no entanto, para as EA percebe-se aumento na produção de metano do verão (MSD - 46,5 e MOD - 51,9) para o inverno (MSD - 75,94 e MOD - 76,28, P = 0,0001). As médias do FP foram diferentes entre as estações do ano, sendo crescentes do verão (2,92) para o inverno (3,52). Não foram observadas diferenças significativas (P>0,05) para as OF em e para as EA para as percentagens molares dos ácidos acético, propiônico e butírico e também para a relação acético:propriônico e pH. O manejo do pastejo, considerando a OF e as EA, pode ser uma ferramenta importante de manipulação da MSD e MOD. A produção de metano é estimulada quando se intensifica a utilização da forragem produzida durante o verão. No inverno há maior eliminação do metano produzido considerando a MSD e MOD. No inverno verifica-se avaliando o FP que há maior atividade microbiana. / This study aimed to analyze the gas production by in vitro digestion Marandu palisadegrass [(Brachiaria brizantha (Hochst ex A. Rich) Stapf], when subjected to four grazing intensities, represented by herbage allowance (HA) 5 , 10 15 and 20% (kg DM/100 kg live weight / day). The experiment was conducted at the Faculdade de Zootecnia e Engenharia de Alimentos - FZEA / USP in Pirassununga / SP, in a pasture with Brachiaria brizantha. A randomized complete block design with 4 replications. The area of 25.2 ha was divided into 16 experimental units of 1.575 ha, divided into 5 paddocks of 3150 m2, in rotationally stocked pasture under a 35 day of grazing cycle (seven days of occupation and 28 days of rest). The animals used were Nellore cattle, with initial body weight of 250 kg and approximately 15 months of age. For the gas production, testing were according to the semi-automatic technique. The data from cumulative gas production were generated using a pressure transducer and a data logger (PDL800, LANA / CENA / USP, Piracicaba-SP, Brazil). The substrate used in triplicate with bovine rumen fluid as inoculum. Three fistulated Holstein cows were donors of inoculum. To prepare the inoculum was used 50% of the liquid phase and 50% of the solid phase of rumen contents. Measurements gases were at 6, 12, 18 and 24 hours after inoculation. The analysis of volatile fatty acids (acetic, propionic and butyric acids) by gas chromatography. Degradability of dry mater in vitro was determined after 24 hours, together with the partition factor (PF). Samples were used as substrate during laboratory tests were collected for six grazing cycles during 2004, specifically January, February, March, May, July and August. The seasons (SE), the cycles of months of January and February were designated as summer, the cycles of months of March and May and autumn and the cycles ofmonths of July and August and winter. A linear behavior was observed for values Total production of gas, organic matter digestible (OMD) and dry matter digestible (DMD) and the determination coefficients obtained were 0.96, 0.94, 0.81 respectively. The volume of methane in mL / g and DMD OMD produced during fermentation was similar, whereas the OF, however, for EA sees an increase in methane production of summer (DMD - OMD and 46.5 - 51.9) for winter (DMD - 75.94 and OMD - 76.28, P = 0.0001). The averages of PF were different between the seasons, and growing summer (2.92) for the winter (3.52). There were no significant differences (P> 0.05) for the HA and in the SE to the molar percentages of acetic, propionic and butyric acids as well as for the Acetic:Propionic and pH . Grazing management, considering the HA and the SE may be an important tool of manipulation of DMD and OMD. Methane production is stimulated when it enhances the use of forage produced during the summer. In winter there is a greater elimination of methane produced considering the DMD and OMD. In the winter occurs evaluating the PF that there is greater microbial activity.
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Influência da estrutura dos pastos de capim tanzânia (Panicum maximum Jacq.) sobre o comportamento ingestivo de cabras F1 Boer x Saanen /Fernandes Junior, Jalme de Souza. January 2007 (has links)
Resumo: Neste estudo foi avaliado o comportamento ingestivo de cabras F1 Boer X Saanen, mantidas diurnamente em pastagens de capim Tanzânia (Panicum maximum Jacq.), em sistema de pastejo com lotação rotacionanada com o ciclo de pastejo de 36 dias, sendo 33 dias de período de descanso e 3 dias de período de ocupação. A área do estudo foi dividida em 12 piquetes de 990 m2 , distribuídos em 6 blocos. Cada piquete foi subdivido para obtenção de dois sistemas (tratamentos) com resíduo de forragem pós pastejo distintos (TBR = baixo resíduo - 1500 kg de M.S./ha e TAR alto resíduo - 3000 kg de M.S./ha ) controlados através da intensidade de pastejo aplicada. Cada piquete foi pastejado por três dias consecutivos (D1, D2 e D3) e constituíram os sub-sub-tratamentos. Foram efetuadas medidas na estrutura do pasto como massa, distribuição espacial dos componentes morfológicos, altura e densidade volumétrica e avaliadas as respostas animais (tempo de pastejo, taxa de bocado e tamanho de bocado) em cada dia de pastejo, nos dois resíduos. As avaliações foram realizadas durante três ciclos de pastejo consecutivos (sub-tratamentos). As quantidades de matéria seca, matéria verde seca, de folhas e a altura do dossel foram maiores no TAR em relação ao TBR e reduziram a quantidade com o decorrer dos dias de pastejo. A quantidade de material morto não diferiu entre os dias e os tratamentos estudados. A quantidade de haste foi menor no TBR em relação ao TAR e não diferiu entre os dias de pastejo. A densidade volumétrica (DV) da matéria seca, da matéria verde seca e do material morto foram maiores no TBR em relação ao TAR e aumentaram do D1 para o D3. A DV da haste no estrato potencialmente pastejável (EPP = 50% da altura do dossel) foi maior no TBR em relação ao TAR e aumentou do D1 para o D3. A porcentagem de folha no EPP comportou-se de forma inversa ao DV da haste do EPP...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This study evaluated the grazing behavior of F1 Boer x Saanen goats, during daytime, maintained in a tropical pasture (Panicum maximum Jacq), under rotationally stocked pasture in different sward structure. The area was divided into 12 paddocks of 990 m2 each, allocated in six blocks (repetitions). Each paddock was divided into two identical plots (treatments, TRT) with high post grazing residue (THR, 3.0 t/ha of dry matter; DM) and low post grazing residue (TLR, 1.5 t/ha DM). Each plot was grazed for three consecutive days (D1, D2 and D3) before animals were rotated. Sward structure measurements consisted of herbage mass, spatial distribution of morphological components, sward height and bulk density (BD). Measurements were conducted during three consecutive grazing cycles of 36 d. The herbage mass, green herbage mass, green leaves mass and sward height were higher in THR than in TLR, and decreased from D1 to D3. Dead herbage mass did not differ between treatments or among days. Stem mass was lower in TLR than in THR, but did not differ among days. The total herbage mass BD, green mass BD and dead herbage mass BD were higher in TLR than in THR, and increased from D1 to D3. The top one-half stratum (i.e., the grazed potentially stratum) had a stem mass BD higher in TLR than in THR and that increased from D1 to D3. Inversely, the leaf percentage on the top one-half stratum was lower in TLR than in THR and decreased from D1 to D3. Bite rate did not differ between treatments or among days. In contrast, bite mass was higher in THR than in TLR, and decreased from D1 to D3. This study suggested that measurements of sward height, leaf bulk density and herbage mass could not be sufficient for establishing tropical pastures management, in particular when pastures vary greatly in sward structure from top to bottom of canopy. / Orientador: Kleber Tomás de Resende / Coorientador: Ricardo Andrade Reis / Banca: Ana Claudia Ruggieri / Banca: Patrícia Menezes Santos / Mestre
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Estudo da produção de gases pela digestibilidade in vitro do capim-Marandu [Brachiaria brizantha (Hochst ex A. Rich) Stapf], submetido a intensidades de pastejo / Study of gas production by in vitro digestibility Marandu palisadegrass [Brachiaria brizantha (Hochst ex A. Rich) Stapf], submitted to grazing intensitiesWilson Aparecido Marchesin 04 March 2010 (has links)
A presente pesquisa teve como objetivo analisar a produção de gases pela digestão in vitro do capim-Marandu [(Brachiaria brizantha (Hochst ex A. RICH) STAPF], quando submetido a quatro intensidades de pastejo, representadas pelas ofertas de forragem (OF) 5, 10 15 e 20% (kg de MSV/100 kg de peso animal/dia). O experimento foi realizado na Faculdade de Zootecnia e Engenharia de Alimentos - FZEA/USP, no município de Pirassununga/SP, Numa pastagem formada com Brachiaria brizantha. O delineamento experimental foi em blocos completos casualizados com 4 repetições. A área de 25,2 ha foi dividida em 16 unidades experimentais de 1,575 ha, subdivididas em 5 piquetes de 3150 m2, a fim de permitir um ciclo de pastejo de 35 dias, (sendo sete dias de ocupação e 28 dias de descanso). Os animais utilizados foram bovinos da raça Nelore (Bos taurus indicus L.) com peso médio inicial de 250 kg e aproximadamente 15 meses de idade. Para a técnica de produção de gases, os ensaios foram realizados de acordo com a técnica semi-automática. Os dados acumulativos da produção de gases foram gerados usando um transdutor de pressão e um \"data logger\" (PDL800, LANA/CENA/USP, Piracicaba/SP, Brazil). O substrato foi utilizado em triplicata com líquido ruminal de bovinos como inoculo. Três fêmeas bovinas fistuladas adultas da raça holandesa foram utilizadas como doadoras de inoculo. No preparo do inoculo utilizou-se 50% da fase líquida e 50% da fase sólida do conteúdo ruminal. As medições de gases foram realizadas às 6, 12, 18 e 24 horas após a inoculação. Foram realizadas as determinações de Ácidos Graxos Voláteis (acético, propiônico e butírico),por cromatografia gasosa. A degradabilidade da material seca in vitro foi determinada após 24 horas, juntamente com o fator de partição (FP). As amostras que foram utilizadas como substrato durante os ensaios laboratoriais foram colhidas durante seis ciclos de pastejo durante o ano de 2004, mais especificamente janeiro, fevereiro, março, maio, julho e agosto. Para as estações do ano (EA), os ciclos dos meses de janeiro e fevereiro foram designados como verão, os ciclos dos meses de março e maio como outono e os ciclos dos meses de julho e agosto como inverno. Um comportamento linear foi observado para os valores de Produção total de gases, Matéria Orgânica Digestível (MOD) e Matéria Seca Digestível (MSD) e os coeficientes de determinação obtidos foram 0,96, 0,94, 0,81 respectivamente. O volume de metano em mL/g de MSD e MOD produzido durante a fermentação foi semelhante, considerando as OF, no entanto, para as EA percebe-se aumento na produção de metano do verão (MSD - 46,5 e MOD - 51,9) para o inverno (MSD - 75,94 e MOD - 76,28, P = 0,0001). As médias do FP foram diferentes entre as estações do ano, sendo crescentes do verão (2,92) para o inverno (3,52). Não foram observadas diferenças significativas (P>0,05) para as OF em e para as EA para as percentagens molares dos ácidos acético, propiônico e butírico e também para a relação acético:propriônico e pH. O manejo do pastejo, considerando a OF e as EA, pode ser uma ferramenta importante de manipulação da MSD e MOD. A produção de metano é estimulada quando se intensifica a utilização da forragem produzida durante o verão. No inverno há maior eliminação do metano produzido considerando a MSD e MOD. No inverno verifica-se avaliando o FP que há maior atividade microbiana. / This study aimed to analyze the gas production by in vitro digestion Marandu palisadegrass [(Brachiaria brizantha (Hochst ex A. Rich) Stapf], when subjected to four grazing intensities, represented by herbage allowance (HA) 5 , 10 15 and 20% (kg DM/100 kg live weight / day). The experiment was conducted at the Faculdade de Zootecnia e Engenharia de Alimentos - FZEA / USP in Pirassununga / SP, in a pasture with Brachiaria brizantha. A randomized complete block design with 4 replications. The area of 25.2 ha was divided into 16 experimental units of 1.575 ha, divided into 5 paddocks of 3150 m2, in rotationally stocked pasture under a 35 day of grazing cycle (seven days of occupation and 28 days of rest). The animals used were Nellore cattle, with initial body weight of 250 kg and approximately 15 months of age. For the gas production, testing were according to the semi-automatic technique. The data from cumulative gas production were generated using a pressure transducer and a data logger (PDL800, LANA / CENA / USP, Piracicaba-SP, Brazil). The substrate used in triplicate with bovine rumen fluid as inoculum. Three fistulated Holstein cows were donors of inoculum. To prepare the inoculum was used 50% of the liquid phase and 50% of the solid phase of rumen contents. Measurements gases were at 6, 12, 18 and 24 hours after inoculation. The analysis of volatile fatty acids (acetic, propionic and butyric acids) by gas chromatography. Degradability of dry mater in vitro was determined after 24 hours, together with the partition factor (PF). Samples were used as substrate during laboratory tests were collected for six grazing cycles during 2004, specifically January, February, March, May, July and August. The seasons (SE), the cycles of months of January and February were designated as summer, the cycles of months of March and May and autumn and the cycles ofmonths of July and August and winter. A linear behavior was observed for values Total production of gas, organic matter digestible (OMD) and dry matter digestible (DMD) and the determination coefficients obtained were 0.96, 0.94, 0.81 respectively. The volume of methane in mL / g and DMD OMD produced during fermentation was similar, whereas the OF, however, for EA sees an increase in methane production of summer (DMD - OMD and 46.5 - 51.9) for winter (DMD - 75.94 and OMD - 76.28, P = 0.0001). The averages of PF were different between the seasons, and growing summer (2.92) for the winter (3.52). There were no significant differences (P> 0.05) for the HA and in the SE to the molar percentages of acetic, propionic and butyric acids as well as for the Acetic:Propionic and pH . Grazing management, considering the HA and the SE may be an important tool of manipulation of DMD and OMD. Methane production is stimulated when it enhances the use of forage produced during the summer. In winter there is a greater elimination of methane produced considering the DMD and OMD. In the winter occurs evaluating the PF that there is greater microbial activity.
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Influência da estrutura dos pastos de capim tanzânia (Panicum maximum Jacq.) sobre o comportamento ingestivo de cabras F1 Boer x SaanenFernandes Junior, Jalme de Souza [UNESP] 29 June 2007 (has links) (PDF)
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fernandesjr_js_me_jabo.pdf: 347275 bytes, checksum: 5097d091697cc488ab8afd2df3fe3213 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Neste estudo foi avaliado o comportamento ingestivo de cabras F1 Boer X Saanen, mantidas diurnamente em pastagens de capim Tanzânia (Panicum maximum Jacq.), em sistema de pastejo com lotação rotacionanada com o ciclo de pastejo de 36 dias, sendo 33 dias de período de descanso e 3 dias de período de ocupação. A área do estudo foi dividida em 12 piquetes de 990 m2 , distribuídos em 6 blocos. Cada piquete foi subdivido para obtenção de dois sistemas (tratamentos) com resíduo de forragem pós pastejo distintos (TBR = baixo resíduo – 1500 kg de M.S./ha e TAR alto resíduo – 3000 kg de M.S./ha ) controlados através da intensidade de pastejo aplicada. Cada piquete foi pastejado por três dias consecutivos (D1, D2 e D3) e constituíram os sub-sub-tratamentos. Foram efetuadas medidas na estrutura do pasto como massa, distribuição espacial dos componentes morfológicos, altura e densidade volumétrica e avaliadas as respostas animais (tempo de pastejo, taxa de bocado e tamanho de bocado) em cada dia de pastejo, nos dois resíduos. As avaliações foram realizadas durante três ciclos de pastejo consecutivos (sub-tratamentos). As quantidades de matéria seca, matéria verde seca, de folhas e a altura do dossel foram maiores no TAR em relação ao TBR e reduziram a quantidade com o decorrer dos dias de pastejo. A quantidade de material morto não diferiu entre os dias e os tratamentos estudados. A quantidade de haste foi menor no TBR em relação ao TAR e não diferiu entre os dias de pastejo. A densidade volumétrica (DV) da matéria seca, da matéria verde seca e do material morto foram maiores no TBR em relação ao TAR e aumentaram do D1 para o D3. A DV da haste no estrato potencialmente pastejável (EPP = 50% da altura do dossel) foi maior no TBR em relação ao TAR e aumentou do D1 para o D3. A porcentagem de folha no EPP comportou-se de forma inversa ao DV da haste do EPP... / This study evaluated the grazing behavior of F1 Boer x Saanen goats, during daytime, maintained in a tropical pasture (Panicum maximum Jacq), under rotationally stocked pasture in different sward structure. The area was divided into 12 paddocks of 990 m2 each, allocated in six blocks (repetitions). Each paddock was divided into two identical plots (treatments, TRT) with high post grazing residue (THR, 3.0 t/ha of dry matter; DM) and low post grazing residue (TLR, 1.5 t/ha DM). Each plot was grazed for three consecutive days (D1, D2 and D3) before animals were rotated. Sward structure measurements consisted of herbage mass, spatial distribution of morphological components, sward height and bulk density (BD). Measurements were conducted during three consecutive grazing cycles of 36 d. The herbage mass, green herbage mass, green leaves mass and sward height were higher in THR than in TLR, and decreased from D1 to D3. Dead herbage mass did not differ between treatments or among days. Stem mass was lower in TLR than in THR, but did not differ among days. The total herbage mass BD, green mass BD and dead herbage mass BD were higher in TLR than in THR, and increased from D1 to D3. The top one-half stratum (i.e., the grazed potentially stratum) had a stem mass BD higher in TLR than in THR and that increased from D1 to D3. Inversely, the leaf percentage on the top one-half stratum was lower in TLR than in THR and decreased from D1 to D3. Bite rate did not differ between treatments or among days. In contrast, bite mass was higher in THR than in TLR, and decreased from D1 to D3. This study suggested that measurements of sward height, leaf bulk density and herbage mass could not be sufficient for establishing tropical pastures management, in particular when pastures vary greatly in sward structure from top to bottom of canopy.
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