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Four lactating Holstein cows fitted with ruminal and duodenal cannulae were used in a 4 x 4 Latin square design to determine the effects of feeding raw and heat-treated flaxseed on ruminal fermentation parameters, ruminal fatty acid biohydrogenation (BH), nutrient utilization in various segments of the gastrointestinal tract, and plasma and milk composition of lactating dairy cows. Four diets were formulated: a control diet with no flaxseed (C); a raw flaxseed (RF); a micronized flaxseed (MF); and an extruded flaxseed (EF) diet. Ruminal pH, NH3N and total volatile fatty acids were not affected by dietary treatments. However, feeding flaxseed decreased ( P < 0.01) molar proportion of acetate and increased ( P < 0.01) that of propionate. Ruminal fiber digestion was lower (P < 0.04) for cows fed the flaxseed diets relative to those fed C. Feeding flaxseed had no effect on milk yield, milk fat and protein content, and milk fat yield, but decreased (P = 0.02) milk protein yield. (Abstract shortened by UMI.)

Three studies were conducted to determine the effects of roasting on ruminal degradability of sunflower seeds and the effects of feeding roasted sunflower seeds on ruminal fermentation, nutrient digestibility and milk yield and composition of dairy cows. Experimental treatments were a control diet with no added sunflower seed, a raw sunflower seed diet and a roasted sunflower seed diet. Sunflower seed diets contained 6% fat whereas the control diet contained 3% fat. In study one, two ruminally fistulated cows were used in a randomized complete block design to determine the effects of roasting on ruminal degradation of sunflower seeds. In the second study, three ruminally cannulated lactating Holstein cows were used in a 3 x 3 Latin square experiment to determine the effects of dietary treatments on ruminal fermentation and total tract nutrient utilization. In the last study, three primiparous and six multiparous Holstein cows were used in three 3 x 3 Latin squares to determine the effects of dietary treatments on milk yield and composition.

Thesis (Ph. D.)--University of Missouri-Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves 179-183). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves 179-183). Also available on the Internet.

Made available in DSpace on 2014-06-11T19:32:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-12-16Bitstream added on 2014-06-13T21:05:19Z : No. of bitstreams: 1 silva_zf_dr_jabo.pdf: 288941 bytes, checksum: c6a44e855aa5751be49544caeb8b11a1 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Fundação de Amparo à Pesquisa e ao Desenvolvimento Científico do Maranhão (FAPEMA) / Avaliou-se efeito da inclusão de 0, 15 e 30% de glicerina bruta (GB) na matéria seca (MS) de dietas em substituição ao milho grão moído sobre o consumo de MS, produção de leite (PL), fermentação ruminal e digestibilidade da MS (DMS) em vacas leiteiras. Foram utilizadas seis vacas multíparas, da raça Holandesa providas de cânula permanente de 4” no rúmen, estando no início do experimento com peso médio de 587 ± 39 kg, com 114 ± 29 dias em lactação e produzindo média de 20 ± 1,5 kg/leite em duas ordenhas diárias. As vacas foram distribuídas em dois quadrados latinos 3 x 3 com períodos de 21 dias, sendo 14 de adaptação. As dietas continham silagem de milho, milho grão, farelo de girassol, glúten de milho, uréia, vitaminas, minerais e GB (86% de glicerol, 95% MS, 6% sais e <100 g/kg de metanol) e foram oferecidas ad libitum, duas vezes ao dia, na forma de dieta total. A dieta controle - ausência de GB, continha 36% de milho; a dieta com 15% e 30% de GB continham, respectivamente, 19,3 e 2,8% de milho. A utilização da GB na dieta reduziu a PL (P=0,10), o consumo de MS (P=0,08), os tempos gastos com atividade mastigatória (P<0,03), a digestibilidade da FDN (P<0,04) e a produção de bactérias associadas à fase líquida do rúmen (P=0,04). Não foram observadas diferenças quanto a cinética de degradação e passagem. Porém, houve aumento na concentração de metano quando a GB foi incluída na dieta. A utilização de glicerina bruta (86% de glicerol) em 15% da matéria seca da dieta de vacas em lactação deprime produção de bactérias de fase líquida, digestibilidade da fibra e desempenho. A sua inclusão em até 10% parece ser o limite ótimo / The purpose of this work was to evaluate the effect of the inclusion of 0, 15 and 30% crude glycerin (CG) in the MS diet in replacement of corn grain (diet control) on the ground on the dry matter intake (DMI), milk production (MY), rumen fermentation and dry matter digestibility in dairy cows . We used six multiparous Holstein cows rumen cannulated, being at the experiment with 587±39 kg BW, 114±29 DIM and with average 20±1.5 kg/d MY in two daily milkings, distributed in two 3x3 Latin Square with 21-days periods. The diets contained corn silage (45% DM), corn grain, sunflower meal, corn gluten meal, urea, vitamins, minerals and CG (86% glycerol, 95% DM, salts 6% and <0.1ppm of methanol). Cows were individually fed on total mixed ration in twice daily. The control diet - no glycerin, containing 36% corn, the diet with 15% and 30% contained GB, respectively, 19.3 and 2.8% of the corn. The use of the CG in the diet reduced the MY (P=0.10), DMI (P=0.08), the time chewing activities (P<0.03), NDF digestibility (P=0.04) and the liquid-associated bacteria content (P=0,04). There were no differences in the kinetics of degradation and passage. However, increased methane output when GB was in the diet. The use of crude glycerin (86% glycerol) in 15% of the diet dry matter for lactating cows depresses production of bacteria in the liquid phase, fiber digestibility and performance. Inclusion in up to 10% seems to be the optimum limit

Orientador: Jane Maria Bertocco Ezequiel / Banca: Juliana Borsari Dourado Sancanari / Banca: Weber Vilas Bôas Soares / Banca: Mauro Dal Secco de Oliveira / Banca: Atushi Sugohara / Resumo: Avaliou-se efeito da inclusão de 0, 15 e 30% de glicerina bruta (GB) na matéria seca (MS) de dietas em substituição ao milho grão moído sobre o consumo de MS, produção de leite (PL), fermentação ruminal e digestibilidade da MS (DMS) em vacas leiteiras. Foram utilizadas seis vacas multíparas, da raça Holandesa providas de cânula permanente de 4" no rúmen, estando no início do experimento com peso médio de 587 ± 39 kg, com 114 ± 29 dias em lactação e produzindo média de 20 ± 1,5 kg/leite em duas ordenhas diárias. As vacas foram distribuídas em dois quadrados latinos 3 x 3 com períodos de 21 dias, sendo 14 de adaptação. As dietas continham silagem de milho, milho grão, farelo de girassol, glúten de milho, uréia, vitaminas, minerais e GB (86% de glicerol, 95% MS, 6% sais e <100 g/kg de metanol) e foram oferecidas ad libitum, duas vezes ao dia, na forma de dieta total. A dieta controle - ausência de GB, continha 36% de milho; a dieta com 15% e 30% de GB continham, respectivamente, 19,3 e 2,8% de milho. A utilização da GB na dieta reduziu a PL (P=0,10), o consumo de MS (P=0,08), os tempos gastos com atividade mastigatória (P<0,03), a digestibilidade da FDN (P<0,04) e a produção de bactérias associadas à fase líquida do rúmen (P=0,04). Não foram observadas diferenças quanto a cinética de degradação e passagem. Porém, houve aumento na concentração de metano quando a GB foi incluída na dieta. A utilização de glicerina bruta (86% de glicerol) em 15% da matéria seca da dieta de vacas em lactação deprime produção de bactérias de fase líquida, digestibilidade da fibra e desempenho. A sua inclusão em até 10% parece ser o limite ótimo / Abstract: The purpose of this work was to evaluate the effect of the inclusion of 0, 15 and 30% crude glycerin (CG) in the MS diet in replacement of corn grain (diet control) on the ground on the dry matter intake (DMI), milk production (MY), rumen fermentation and dry matter digestibility in dairy cows . We used six multiparous Holstein cows rumen cannulated, being at the experiment with 587±39 kg BW, 114±29 DIM and with average 20±1.5 kg/d MY in two daily milkings, distributed in two 3x3 Latin Square with 21-days periods. The diets contained corn silage (45% DM), corn grain, sunflower meal, corn gluten meal, urea, vitamins, minerals and CG (86% glycerol, 95% DM, salts 6% and <0.1ppm of methanol). Cows were individually fed on total mixed ration in twice daily. The control diet - no glycerin, containing 36% corn, the diet with 15% and 30% contained GB, respectively, 19.3 and 2.8% of the corn. The use of the CG in the diet reduced the MY (P=0.10), DMI (P=0.08), the time chewing activities (P<0.03), NDF digestibility (P=0.04) and the liquid-associated bacteria content (P=0,04). There were no differences in the kinetics of degradation and passage. However, increased methane output when GB was in the diet. The use of crude glycerin (86% glycerol) in 15% of the diet dry matter for lactating cows depresses production of bacteria in the liquid phase, fiber digestibility and performance. Inclusion in up to 10% seems to be the optimum limit / Doutor

This study was conducted in two trials. The aim was firstly to identify the qualitative characteristics of Atriplex nummularia (Hatfield Select). Goats and sheep were used to identify three palatability groups of plants in the A. nummularia (Hatfield Select) paddock. These palatability groups were compared in terms of quality to one another. Secondly, qualitative and quantitative intakes of A. nummularia (Hatfield Select) by goats and sheep were determined. This was done in a grazing trial lasting five days. A comparison was conducted between goats and sheep as well as between the different days of the grazing period. During the first trial, goats and sheep were used to identify the most-, medium- and least-palatable A. nummularia (Hatfield Select) plants. The regrowth on these plants were harvested and used for laboratory analysis to identify the qualitative differences between these three groups. These samples were also used to determine and compare degradability between the three groups as well as between goats and sheep. Goats and sheep preferred A. nummularia (Hatfield Select) plants with a significantly (p ¡Ü 0.05) higher crude protein (CP), phosphorus (P) and magnesium (Mg) content. The most preferred plants also had higher neutral detergent fibre (NDF), Ca, K, Na, Cl- and Cu content than the least preferred plants, but these were not significant (p > 0.05). A. nummularia (Hatfield Select) provides enough CP for maintenance and production in both goats and sheep. All mineral requirements for maintenance in goats and sheep can be satisfied on A. nummularia (Hatfield Select), except that of Cu. For production (growth and lactation) only P is deficient and needs to be supplemented. A. nummularia (Hatfield Select) makes an ideal drought fodder crop to support the natural veld during the dry season. An overall higher DM, N and NDF rumen degradability of Atriplex was recorded with goats than with sheep. Goats exhibited a significantly (p ¡Ü 0.05) higher DM and N degradation and although a higher NDF degradation was also recorded, this was not significant. The rate of DM, N and NDF rumen degradation was also higher in goats than in sheep. This means that goats have a more favorable rumen environment for the digestion of A. nummularia (Hatfield Select). DM and N degradation were also significantly (p ¡Ü 0.05) higher in the most palatable group than the least palatable group. NDF degradability decreased with palatability. This means that the most palatable plants have a higher digestibility and quality than the least palatable plants. In the second experiment, rumen and oesophageal fistulated sheep and goats were allowed to graze A. nummularia (Hatfield Select) for five days. Qualitative and quantitative intakes were determined. The quality and quantity of ingested material were compared between goats and sheep as well as between the different grazing days. There was a significant decline in the quality and quantity of intake over the grazing period. Some parameters were significant, for example CP. The CP concentration declined from 18% to 3.91 % for goats and from 19.88% to 6.61% for sheep. The cell wall constituents (NDF) increased by about 10% from the start to the end of the grazing period. IVDOM decreased by 14% and intakes were almost halved from the start to the end of the grazing period. Other authors have also observed this decrease in quality and quantity of intake over time. The lower quality and quantity in intake was because of a decline in the availability of high quality edible material. At the end of the grazing period, there was very little edible material left which caused an extremely low quality and quantity of intake. Rumen NH3-N concentrations also declined as the dietary CP declined, but it was still present in high enough concentrations to sustain the rumen micro flora population. Rumen VFA decreased over the grazing period. The acetic acid to propionic acid ratio increased towards the end of the grazing period. This caused a decline in the efficiency of utilization of ME for maintenance as acetic acid has an efficiency in utilization of ME of 59% and propionic acid of 86% (McDonald et al., 1995). This means that energy will have to be supplemented to sustain maintenance. / Dissertation (MSc (Agric) Animal Science, Nutrition)--University of Pretoria, 2007. / Animal and Wildlife Sciences / unrestricted

In recent times there has been much concern among animal product consumers about the safety and use of antimicrobial substances in the production of food for human consumption. This has been driven by the ban of the use of antibiotics at subtherapeutic levels for food animal production in Europe. For this reason, producers are always looking at ‘natural’ alternatives to antibiotics to improve production from their animals. One such alternative is the use of yeast cultures of Saccharomyces cerevisiae in ruminant diets to manipulate rumen fermentation. Yeast culture fed to ruminants has increased production from beef and dairy cattle and sheep as well as stabilizing rumen fermentation under conditions such as rumen acidosis. Yeast culture has been shown to increase the microbial protein supply from the rumen by stimulating growth of bacteria in the rumen. Yeast culture may be used to alleviate the negative effects of rumen antimicrobials such as monensin on rumen microbial populations and fibre digestion. Four separate sets of experiments were undertaken. In the first set of experiments, the effects of 10 specific yeast cultures on the growth of 3 selected rumen bacteria was evaluated. The rumen bacteria evaluated were Ruminococcus albus, Selenomonas ruminantium and Ruminobacter amylophilus. It was found that only two of the ten strains of yeast tested were able to consistently decrease the lag time of the selected rumen bacteria. In the second set of experiments, the effects of yeast culture addition on a rumen fluid based batch culture fermentation was analysed by measuring the gas pressure produced by the fermentation. The results obtained were too variable to draw any conclusions from the data. In the third set of experiments, the effects of yeast, monensin and their combination were evaluated in rumen simulating continuous cultures. It was found that monensin increased the efficiency of the fermentation but decreased the total anaerobic bacteria. Yeast culture increased the total anaerobic bacteria. UNI yeast alleviated the reduction in anaerobic bacteria when combined with monensin. The last set of experiments were an attempt to develop an assay to measure the potential of certain yeast strains to stimulate rumen fermentation. The potential assays were based on the ability of yeasts to stimulate a growing culture of Ruminococcus albus. None of the assays attempted showed obvious potential as a future assay. From the study it seems that yeasts stimulate the growth of certain species of ruminal bacteria but not all yeast strains are able to do so. Yeast supplementation may be fed in combination with monensin in order to reduce the impact of monensin on the microbial populations of the rumen. / Dissertation (MSc(Agric))--University of Pretoria, 2008. / Animal and Wildlife Sciences / unrestricted

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