Cattle operations in the Southeastern United States are primarily cow-calf and stocker based and rely heavily on forage. As such, research regarding supplementation strategies that are specific to both the forage cultivars and management strategies that are common in the region are necessary for accurate nutritional recommendations. Additionally, further research is necessary to develop solutions to cope with the negative effects of fescue toxicosis that are common in the region. Therefore, the objectives of this dissertation are to examine supplementation strategies specific to growing cattle as well as to investigate methods of reducing ergot alkaloid intake. Corn gluten feed (CGF) is a common corn co-product that is used to supply supplemental energy and protein. Experiment 1 investigated the effect of supplementing CGF or corn to grazing cattle and found that in grazing situations, growing cattle that are supplemented with CGF have greater average daily gain (ADG) and feed efficiency compared to those supplemented with corn (P  0.03). This improvement in ADG was without changes in subcutaneous fat accretion (P = 0.87), as there were no differences among treatments in fat thickness at the 12th rib (P = 0.54). This improvement in growth and efficiency was thought to be due to differences in the digestibility of fiber in the rumen. Therefore, experiment 2 was designed to investigate the effect of corn or CGF supplementation on apparent total tract nutrient digestibility when cattle are fed a forage-based diet. However, the results from this experiment indicated that there were no changes in neutral detergent fiber digestibility (P > 0.19). In fact, heifers supplemented with corn at 0.25% BW had greater acid detergent fiber digestibility compared with those supplemented with corn at the same level (P = 0.05). Ultimately, this resulted in animals being supplemented with corn tending to have greater organic matter digestibility compared to those supplemented with CGF (P = 0.10). Therefore, the improvement in performance that is observed when grazing cattle are supplemented with CGF compared to corn does not seem to be due to improvements in fiber digestibility. Experiment 3 examined if prolonged storage of ensiled tall fescue would result in the degradation of ergot alkaloids to levels similar to that of hay. Surprisingly, there were no differences among hay or haylage samples for individual or total ergot alkaloids regardless of storage time. Ergovaline concentrations, however, declined after 30 d of storage and were similar throughout the remainder of the storage period. Although no differences were observed among treatments, the reduction of ergovaline concentrations after 30 d of storage indicate that short-term storage may help to reduce the negative effects of fescue toxicosis for the animals consuming it. / Doctor of Philosophy / The Southeastern United States is home to approximately 20% of the country's cattle population and is a major source of feeder cattle that enter the feedlots in the Midwest. The primary nutrient source for cattle in this region is grazeable forage, and production systems in the Southeast are primarily cow/calf or stocker based, with few forage or grain-based finishing operations. Much of the grazeable area is in a portion of the country termed the fescue belt since the primary species of grass is tall fescue. While this species has desirable forage characteristics, it is commonly infected with a fungal endophyte that produces ergot alkaloids that are toxic to livestock. These ergot alkaloids are attributed to billions of dollars of lost revenue and reduced animal welfare. While the forage in the Southeast is of relatively good quality, many producers choose to supplement grazing cattle. This is particularly common during winter months when forage is dormant, and when desired levels of growth exceed what can be provided by forage alone. However, the source of supplemental nutrients can induce changes in the efficiency of forage digestion, and the optimal nutrient source differs when compared to grain-based diets. Therefore, it is important for producers and nutritionists in the Southeast to have access to data relevant to their region of the country. The objectives of this dissertation are to evaluate supplementation strategies relevant for the Southeast, and to evaluate a potential method of mitigating the negative effects of fescue toxicosis in harvested forage. Corn gluten feed has previously been shown to improve performance to a greater extent compared to corn when included in a forage-based diet in a dry-lot setting but has not been investigated in grazing situations. Therefore, we investigated if this effect would be present in grazing situations. Using growing cattle and an automated feeding system, we demonstrated that grazing cattle supplemented with corn gluten feed had greater growth performance compared to those supplemented with corn. To investigate if this was due to differences in nutrient digestibility, we then investigated how total tract digestibility was influenced by supplement type and inclusion level in forage-based diets. However, our results indicated that at relatively small levels of inclusion, total tract digestibility is not impacted by supplement type. To investigate methods to control fescue toxicosis in livestock, we conducted an experiment to determine if ergot alkaloid concentrations in forage harvested as hay and haylage can be reduced through prolonged storage. While there were no differences in concentrations among forage types (hay and haylage), there was a beneficial effect of day for ergovaline concentrations, one of the principal toxins that is present in endophyte-infected tall fescue. This suggests that profits for livestock producers as well as animal welfare can be improved through the short-term storage of harvested tall fescue. Collectively, these experiments demonstrate potential methods for beef producers in the Southeastern U.S. to improve growth in grazing cattle. As researchers continue to improve the understanding of the interaction between grazing livestock and supplementation programs, improved recommendations can be made regarding nutrition programs and ultimately result in a more efficient and profitable operation.

Protein is an important fraction within bovine milk. This milk protein is not only vital for calf growth and development, but also includes bioactive proteins and peptides that have been shown to enhance the health of animals and humans. Research efforts are focusing on factors, such as nutrition, that can influence the quantity and profile of proteins within the bovine milk proteome. The research outlined herein investigated the impact of diet on the bovine milk proteome. The first experiment examined whether dietary inclusion of grape marc (GM), a condensed tannin (CT) containing by-product from the viticulture industry, could alter the bovine milk proteome through altered nitrogen (N) metabolism. In this experiment, 10 lactating Holstein cows were fed either 2.0 kg dry matter (DM)/ cow/ day of beet pulp: soy hulls in a 50% mixture (control), or 1.5 kg DM/ cow/ day of GM as part of a balanced dairy cow ration for a 28-d trial. Milk samples were obtained for analysis of the high- and low-abundance protein fractions. Skimmed milk samples collected for high-abundance protein analysis were measured using high performance liquid chromatography (HPLC), and liquid-chromatography tandem mass spectrometry (LC-MS/MS) was used to identify proteins in the low-abundance protein enriched fraction. Skimmed milk samples collected for low-abundance milk protein analysis were fractionated and enriched to remove higher abundance proteins. Enriched milk samples were then digested and labeled with isobaric tandem mass tags (TMT) prior to protein identification using LC-MS/MS analysis. There were no changes in the high-abundance protein fraction in response to diet; however, 16 of 127 low-abundance proteins were identified at different relative-abundances due to diet (P ≤ 0.05). While there were no alterations in the metabolic or N status of animals due to GM supplementation, the 12% change in the low-abundance milk protein fraction highlighted the potential for dietary alteration of the bovine milk proteome. A second experiment evaluated the inclusion of alternative forage crops (AFC) as a means to alter the bovine milk proteome. In this experiment, both the skimmed milk and milk fat globule membrane (MFGM) protein fractions were included in analysis. Milk samples were collected from 16 lactating Jersey cattle included in a 21-d grazing experiment, where cows were offered one of two diets. The control group (CON, n=8) grazed a grass-legume pasture mixture containing orchardgrass (Dactylis glomerata), timothy (Phleum pratense), Kentucky bluegrass (Poa pratensis), and white clover (Trifolium repens). The treatment group (AFC, n=8) grazed a similar base pasture that was strip-tilled with oat (Avena sativa), buckwheat (Fagopyrum esculentum), and chickling vetch (Lathyrus sativus) so that the AFC species comprised 10% of the AFC group’s pasture DM intake (DMI). Milk samples were collected for HPLC analysis of the high abundance milk proteins, and LC-MS/MS analysis of the low abundance protein enriched skim milk fraction and MFGM-associated protein fraction. Cows that grazed pastures containing AFC had higher αs1-CAS content (P = 0.005), and higher relative-abundances of 7 low-abundance proteins within the skim milk and MFGM fractions (P ≤ 0.05). While it is plausible that the inclusion of AFC in pasture increased nutrient availability to the mammary gland, the specific mechanisms that could have caused the shifts observed remain unclear. Further investigation is necessary to fully understand the role of diet and the milk protein profile.

A sociedade está cada vez mais exigente com relação à qualidade dos produtos consumidos e se preocupa com os benefícios para a saúde. Neste contexto, objetivou-se avaliar o efeito da inclusão de níveis de óleo de canola na dieta de vacas sobre amanteiga e muçarela, buscando produtos mais saudáveis para o consumo humano. Foram utilizadas 18 vacas Holandesas, em estágio intermediário de lactação, com produção média de 22 (± 4) Kg de leite/ dia, as quais foram distribuídas em dois quadrados latinos 3x3 contemporâneos e receberam as dietas experimentais: T1- Controle (0% de inclusão de óleo); T2- 3% de inclusão de óleo de canola e T3- 6% de inclusão de óleo de canola. O perfil lipídico foi determinado através de cromatografia gasosa, além da avaliação de qualidade nutricional, realizada através de equações utilizando os ácidos graxos obtidos no perfil lipídico, análises físico-químicas determinadas pela metodologia do Instituto Adolfo Lutz e análises microbiológicas. Houveram problemas durante processamento do leite, gerando alterações de tecnologia de fabricação do produto manteiga, obtendo-se outro produto, o creme de leite, ao invés de manteiga, além de prejuízos na qualidade microbiológicas do creme de leite e muçarela. A inclusão de óleo de canola na dieta em lactação reduziu quadraticamente os ácidos graxos de cadeia curta e proporcionou aumento quadrático dos ácidos graxos de cadeia longa, dos ácidos graxos insaturados e ácidos graxos monoinsaturados na muçarela. A relação ácidos graxos saturados/ ácidos graxos insaturados (AGS/ AGI) e a relação ômega-6/ômega-3, assim como os índices de aterogenicidade e trombogenicidade, na muçarela, reduziram linearmente 25,68%, 31,35%; 32,12% e 21,78%, respectivamente, quando comparando T1 e T3. No creme de leite, houve redução linear dos ácidos graxos de cadeia curta e média, bem como, os ácidos graxos saturados e a relação ácidos graxos saturados/ ácidos graxos insaturados (AGS/ AGI) em 41,07%; 23,82%; 15,91% e 35,59%, respectivamente, enquanto os ácidos graxos de cadeia longa, ácidos graxos insaturados e ácidos graxos monoinsaturados aumentaram linearmente 41,40%; 28,24% e 32,07%, nesta ordem, quando comparando T1 com T3. Os índices de aterogenicidade e trombogenicidade reduziram de forma linear, enquanto o índice h/H (razão ácidos graxos hipocolesterolêmicos e hipercolesterolêmicos) aumentou linearmente. A composição físico-química de ambos derivados e o rendimento da muçarela não apresentaram efeito significativo com a inclusão do óleo de canola, exceto a proteína bruta da muçarela que apresentou aumento linear e a gordura do creme de leite que apresentou efeito quadrático. As análises microbiológicas mostram contagens muito elevadas de microrganismos, sugerindo que os produtos não apresentam qualidade microbiológica, decorrente da ausência do processo de pasteurização do creme e da baixa eficiência do tratamento térmico aplicado ao leite destinado a produção da muçarela. Conclui-se que a adição de óleo de canola na dieta de vacas lactantes proporciona muçarela e creme de leite mais saudáveis para o consumo humano, pois apresentaram perfil lipídico mais rico em ácidos graxos insaturados, além da série ômega-3 e ácido oleico, entretanto, devido a problemas de processamento, estes produtos obtidos, não estão aptos ao consumo devido à ausência de qualidade microbiológica. / Society is increasingly demanding with regard to the quality of the products consumed and worries about the health benefits. In this context, the objective was to evaluate the effect of inclusion of canola oil levels in cows diet on amanteiga and mozzarella, seeking healthier products for human consumption. 18 Holstein cows were used in middle stage of lactation, with average production of 22 (± 4) kg of milk / day, which were distributed in two 3x3 squares contemporary Latin and received the experimental diets: T1- control (0% of inclusion oil); T2 3% inclusion of canola oil and T3 6% canola oil inclusion. The lipid profile was determined by gas chromatography, in addition to evaluation of nutritional quality, performed using equations using fatty acids obtained in the lipid profile, physical and chemical analysis determined by the methodology of the Institute Adolfo Lutz and microbiological analysis. There were problems during processing of milk, generating fabrication technology changes butter product to give another product, the cream instead of butter, as well as losses in the microbiological quality of milk cream and mozzarella. The canola oil inclusion in the diet of lactating quadratically reduced the short-chain fatty acids and yielded quadratic increase in long-chain fatty acids, unsaturated fatty acids and monounsaturated fatty acids in the mozzarella. The ratio saturated fatty acid / unsaturated fatty acids (SFA / UFA) and the ratio omega-6 / omega-3 as well as the contents of atherogenicity and thrombogenicity in mozzarella, linearly decreased 25.68%, 31.35%; 32.12% and 21.78%, respectively, when comparing T1 and T3. In cream, there was a linear reduction of the fatty acids of short and medium chain, as well as saturated fatty acids and the ratio saturated fatty acid / unsaturated fatty acids (SFA / UFA) in 41.07%; 23.82%; 15.91% and 35.59% respectively, while long chain fatty acids, unsaturated fatty acids and monounsaturated fatty acids 41.40% increased linearly; 28.24% and 32.07%, in that order, when comparing T1 to T3. The index atherogenicity and thrombogenicity reduced linearly, while the ratio h / H (ratio hypocholesterolemic hypercholesterolemic fatty acids) increased linearly. The physical and chemical composition of both derivatives and the income of mozzarella no significant effect with the inclusion of canola oil, except the crude protein of mozzarella that showed a linear increase and fat cream which showed a quadratic effect. Microbiological analyzes show very high scores of microorganisms, suggesting that the products do not present microbiological quality, due to the absence of the cream pasteurization process and low efficiency of the thermal treatment of the milk for the production of mozzarella. We conclude that the addition of canola oil in the diet of lactating cows provides mozzarella and healthier cream for human consumption, as presented richer lipid profile in unsaturated fatty acids, as well as omega-3 series and oleic acid, however because of processing problems, the products obtained are not apt for consumption due to the lack of microbiological quality.

O fósforo (P) é responsável por funções essenciais nos ruminantes, tais como transporte de energia, formação dos fosfolipídeos e efeito tampão no rumem. A falta desse mineral pode prejudicar o apetite e conseqüentemente causar a perda de peso. Entretanto, o seu fornecimento em excesso leva a perda por excreção que pode causar poluição quando o P alcança as águas de rios e mananciais. O objetivo desse trabalho foi utilizar a modelagem matemática como ferramenta para o estudo do metabolismo e cinética do P em ruminantes. Dezesseis ovinos machos jovens foram alimentados com dietas contendo diferentes fontes de cálcio (Ca) e níveis semelhantes de P e Ca. Após adapatação às dietas os animais receberam uma injeção única contendo 7,4 MBq de 32P e 7,4 MBq de 45Ca. As coletas de fezes, urina e sangue foram feitas diariamente durante sete dias para análise desses minerais. Depois de sacrificar os animais, foram coletadas amostras de tecidos moles (rins, fígado, coração e músculo) e ossos para análise do P e do Ca. Num primeiro trabalho, os dados obtidos foram utilizados para revisar o modelo Vitti, e dados referentes ao P do fitato foram adicionados ao modelo. Os resultados referentes aos fluxos obtidos entre os ossos e o plasma (23,8 e 22,9 g/d) foram maiores do que os fluxos entre os tecidos e o plasma (3,35 e 2,83 g/d), refletindo a maior precisão do modelo revisado. As predições do modelo quanto à absorção e excreção do P do fitato poderão ser utilizadas em estudos futuros relativos ao seu metabolismo em ruminantes. No segundo trabalho, os tratamentos contendo as diferentes fontes de cálcio (calcário, feno de alfafa, polpa cítrica e farinha de conchas de ostras) foram comparados através da análise estatística dos fluxos obtidos de dois modelos: Vitti revisado (VD) e modelo Fernandez revisado por Lopes (FL). Os resultados referentes à presença de Ca líquido nos ossos estão de acordo entre os modelos VD e FL, no entanto o modelo VD apresentou maior valor de retenção líquida de Ca nos tecidos. Ambos os modelos mostraram o mesmo padrão para os fluxos de P, assim como para as retenções líquidas de P nos ossos e tecidos. Os modelos refletiram de maneira semelhante o metabolismo do P. No terceiro trabalho, o modelo VD foi utilizado para avaliar o efeito de diferentes níveis de suplementação de P na dieta sobre o metabolismo do P em ovinos em crescimento (0; 1,5; 3,0; 4,5 g de P/animal/dia correspondendo aos tratamentos T1, T2, T3 e T4 respectivamente). O maior valor para o P absorvido nos ossos foi obtido pelos animais do T4 que excretaram os maiores níveis de P nas fezes. O T3 forneceu o melhor nível de P para essa categoria de animal, pois o P absorvido nos ossos e tecidos indicou que a absorção total de P foi adequada. Como conclusão final dos três trabalhos realizados, pode-se afirmar que o modelo VD é uma importante ferramenta para ser utilizada no estudo do metabolismo do P em ruminantes / The phosphorus (P) is responsible for essential functions in ruminants as such energy transportation, phospholipids formation and buffer effect on rumen. The lack of this mineral can impair appetite therefore causing loss of weigh. However the excess of P provided leads to losses through excretion that can cause pollution when it reaches river and stream water. The objective of this work was to apply mathematical modeling as a tool to study P metabolism and kinetics in ruminants. Sixteen young male sheep were fed with diets containing sources of Ca and similar levels of P and Ca. After adaptation to diets the animals received a single injection of 7,4 MBq of 32P and 7,4 MBq of 45Ca. Collections of feces, urine and blood were made daily for 7 days for further P and Ca analyses. After animals were sacrificed, samples were collected from soft tissue (kidney, liver, heart and muscle) and bone for P and Ca analyses. In the first paper, the obtained data was used to revise Vitti model, and data from phytate P were added to the model. The results concerned to the fluxes obtained between bone and plasma (23,8 and 22,9 g/d) were greater than the fluxes between tissue and plasma (3,35 and 2,83 g/d) reflecting the better precision from the revised model. The model prediction for phytate P absorption and excretion can be further used in studies related do phytate P metabolism in ruminants. In the second paper, the treatments containing different Ca sources (limestone, alfalfa hay, citrus pulp and oyster shell meal) were compared using statiscal analyses from the fluxes obtained from two models: Vitti model revised (VD model) and Fernandez model revised by Lopes (FL model). The results concerned to the presence of net Ca in bone are in agreement between the two models; however the net Ca retention in tissue was greater for VD model. Both models showed the same pattern for P fluxes, as well as for net P retention in bone and tissue. The models reflected P metabolism in the same way. In the third paper, the Vitti model revised was used to assess the effect of different levels of P supplementation (0; 1,5; 3,0 and 4,5 g P/animal/ day corresponding to T1, T2, T3 and T4 respectively) upon P metabolism in growing sheep. The higher value for P absorbed in bone was obtained by animals from T4 that also excreted the greater levels of P in feces. The T3 provided the best P level for this animal category because P absorbed in bone and tissue indicated that total P absorption was adequate. As final conclusion from the accomplished work, it can be claimed that the revised Vitti model is an important tool to be used to study P metabolism in ruminants

This study was conducted to evaluate the effect of microbial feed additives Megasphaera elsdenii NCIMB 41125 and Saccharomyces cerevisiae 1026, individually and combined on rumen pH,ammonia-N and volatile fatty acids (VFAs) fermentation. An in vitro batch fermentation was conducted using rumen fluid from two early lactating Holstein cow donor fed the TMR for lactating cows which was evaluated under two diets, differing in concentrate to forage ratio. The diets were high concentrate, a 60:40 concentrate to forage ratio diet (HC) and low concentrate, a 40:60 (LC) concentrate to forage ratio diet. The treatments were; Control (diet with no additives), Me (diet with M. elsdenii NCIMB 41125 10mm (108 CFU/ml)), LY (diet with live yeast, S. cerevisiae 1026), and Me+LY (diet with mixture of M. elsdenii and S. cerevisiae). The average rumen pH was 5.8 and ammonia nitrogen was not affected by Me and LY supplemented separately or in combination (Me+LY) in both low and high concentrate diets. Total VFAs were increased with the addition of LY alone and in combination Me+LY+Me) in high concentrate diet only but the addition of Me had no effect in both diets. Acetate, lactate and A: Pr were decreased (P<0.05) by all the treatments (Me and LY alone and in combination) on both diets, except in high concentrate diet where the addition of Me tended to decrease (P<0.07) acetate and had no effect on lactate. Propionate was increased by all the treatments in low concentrate diet and tended toincrease (P<0.08) by addition of Me and Me+LY in high concentrate diet. In a low concentrate diet, butyrate was increased by LY but tended to be decreased by Me, however, all the treatments lacked effects on high concentrate diet. Live yeast appears to act differently compared to Me by showing two times more effects on high than low concentrate diets.This in vitro study showed that both Me and LY had a tendency to modify rumen fermentation and that might indicate their potential to mitigate the metabolic challenges and improve energy status of Holstein dairy cows during the transition and early lactation period. However, there is a need for further research that will include in vivo study. / Agriculture, Animal Health and Human Ecology / M.Sc. (Agriculture)

O fósforo (P) é responsável por funções essenciais nos ruminantes, tais como transporte de energia, formação dos fosfolipídeos e efeito tampão no rumem. A falta desse mineral pode prejudicar o apetite e conseqüentemente causar a perda de peso. Entretanto, o seu fornecimento em excesso leva a perda por excreção que pode causar poluição quando o P alcança as águas de rios e mananciais. O objetivo desse trabalho foi utilizar a modelagem matemática como ferramenta para o estudo do metabolismo e cinética do P em ruminantes. Dezesseis ovinos machos jovens foram alimentados com dietas contendo diferentes fontes de cálcio (Ca) e níveis semelhantes de P e Ca. Após adapatação às dietas os animais receberam uma injeção única contendo 7,4 MBq de 32P e 7,4 MBq de 45Ca. As coletas de fezes, urina e sangue foram feitas diariamente durante sete dias para análise desses minerais. Depois de sacrificar os animais, foram coletadas amostras de tecidos moles (rins, fígado, coração e músculo) e ossos para análise do P e do Ca. Num primeiro trabalho, os dados obtidos foram utilizados para revisar o modelo Vitti, e dados referentes ao P do fitato foram adicionados ao modelo. Os resultados referentes aos fluxos obtidos entre os ossos e o plasma (23,8 e 22,9 g/d) foram maiores do que os fluxos entre os tecidos e o plasma (3,35 e 2,83 g/d), refletindo a maior precisão do modelo revisado. As predições do modelo quanto à absorção e excreção do P do fitato poderão ser utilizadas em estudos futuros relativos ao seu metabolismo em ruminantes. No segundo trabalho, os tratamentos contendo as diferentes fontes de cálcio (calcário, feno de alfafa, polpa cítrica e farinha de conchas de ostras) foram comparados através da análise estatística dos fluxos obtidos de dois modelos: Vitti revisado (VD) e modelo Fernandez revisado por Lopes (FL). Os resultados referentes à presença de Ca líquido nos ossos estão de acordo entre os modelos VD e FL, no entanto o modelo VD apresentou maior valor de retenção líquida de Ca nos tecidos. Ambos os modelos mostraram o mesmo padrão para os fluxos de P, assim como para as retenções líquidas de P nos ossos e tecidos. Os modelos refletiram de maneira semelhante o metabolismo do P. No terceiro trabalho, o modelo VD foi utilizado para avaliar o efeito de diferentes níveis de suplementação de P na dieta sobre o metabolismo do P em ovinos em crescimento (0; 1,5; 3,0; 4,5 g de P/animal/dia correspondendo aos tratamentos T1, T2, T3 e T4 respectivamente). O maior valor para o P absorvido nos ossos foi obtido pelos animais do T4 que excretaram os maiores níveis de P nas fezes. O T3 forneceu o melhor nível de P para essa categoria de animal, pois o P absorvido nos ossos e tecidos indicou que a absorção total de P foi adequada. Como conclusão final dos três trabalhos realizados, pode-se afirmar que o modelo VD é uma importante ferramenta para ser utilizada no estudo do metabolismo do P em ruminantes / The phosphorus (P) is responsible for essential functions in ruminants as such energy transportation, phospholipids formation and buffer effect on rumen. The lack of this mineral can impair appetite therefore causing loss of weigh. However the excess of P provided leads to losses through excretion that can cause pollution when it reaches river and stream water. The objective of this work was to apply mathematical modeling as a tool to study P metabolism and kinetics in ruminants. Sixteen young male sheep were fed with diets containing sources of Ca and similar levels of P and Ca. After adaptation to diets the animals received a single injection of 7,4 MBq of 32P and 7,4 MBq of 45Ca. Collections of feces, urine and blood were made daily for 7 days for further P and Ca analyses. After animals were sacrificed, samples were collected from soft tissue (kidney, liver, heart and muscle) and bone for P and Ca analyses. In the first paper, the obtained data was used to revise Vitti model, and data from phytate P were added to the model. The results concerned to the fluxes obtained between bone and plasma (23,8 and 22,9 g/d) were greater than the fluxes between tissue and plasma (3,35 and 2,83 g/d) reflecting the better precision from the revised model. The model prediction for phytate P absorption and excretion can be further used in studies related do phytate P metabolism in ruminants. In the second paper, the treatments containing different Ca sources (limestone, alfalfa hay, citrus pulp and oyster shell meal) were compared using statiscal analyses from the fluxes obtained from two models: Vitti model revised (VD model) and Fernandez model revised by Lopes (FL model). The results concerned to the presence of net Ca in bone are in agreement between the two models; however the net Ca retention in tissue was greater for VD model. Both models showed the same pattern for P fluxes, as well as for net P retention in bone and tissue. The models reflected P metabolism in the same way. In the third paper, the Vitti model revised was used to assess the effect of different levels of P supplementation (0; 1,5; 3,0 and 4,5 g P/animal/ day corresponding to T1, T2, T3 and T4 respectively) upon P metabolism in growing sheep. The higher value for P absorbed in bone was obtained by animals from T4 that also excreted the greater levels of P in feces. The T3 provided the best P level for this animal category because P absorbed in bone and tissue indicated that total P absorption was adequate. As final conclusion from the accomplished work, it can be claimed that the revised Vitti model is an important tool to be used to study P metabolism in ruminants

Submitted by Marlene Santos (marlene.bc.ufg@gmail.com) on 2016-09-08T12:47:37Z No. of bitstreams: 2 Dissertação - Gustavo Chunca Merma - 2016.pdf: 1384828 bytes, checksum: afbfe1a386ecbe619a04c3b198cfeb90 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-09-09T14:29:27Z (GMT) No. of bitstreams: 2 Dissertação - Gustavo Chunca Merma - 2016.pdf: 1384828 bytes, checksum: afbfe1a386ecbe619a04c3b198cfeb90 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-09-09T14:29:27Z (GMT). No. of bitstreams: 2 Dissertação - Gustavo Chunca Merma - 2016.pdf: 1384828 bytes, checksum: afbfe1a386ecbe619a04c3b198cfeb90 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-08-18 / Evaluated degradability kinetic of grass mombasa silage with inclusion levels of cottonseed meal. The treatments were constituted by four CM inclusion levels (0%, 10%, 15%, 20%). The average levels of dry matter in grass mombasa silages differed depending on cottonseed meal levels, ranging from 22.69 to 31.93. The levels of crude protein ranged from 12.51 to 22.45, and significant differences were observed at the same time promoting a reduction in the levels of insoluble fiber and neutral detergent fiber and acid detergent insoluble, thus keeping within the recommended standards, especially the 20% of CM with the highest level and lower losses by gases and effluents. The levels of hydrogenic potential (pH) ranged from 4.88 to 5.17. The nitrogen ammonia content (N-NH3), were within acceptable parameters with 1.30% to 2.59%. The average levels of soluble carbohydrates ranged from 4.60% to 8.90%, with no significant difference between the 10% and 15% levels of CM (P>0.05). The levels of lactic acid, acetic, propionic and butyric ranged from 0.2682 to 1.482; from 0.1759 to 0.3216; 0.011 to 0.0241 and from 0.0012 to 0.00162 respectively, and showed statistical difference (P>0.05) between the levels of cottonseed meal. The “in situ” dry matter degradability (DM) and crude protein (CP), neutral detergent insoluble fiber (NDIF), insoluble acid detergent fiber (IADF), were significantly influenced by the levels of inclusion of cottonseed meal (P<0.05), and highlighted the inclusion level of 20% of cottonseed meal that showed significant levels of disappearance in DM, CP, NDIF And IADF, showing that the acceptable level of cottonseed meal as addition to grass mombasa. / Avaliou-se a cinética da degradabilidade “in situ” da silagem de capim-mombaça com níveis de inclusão de farelo de algodão. Os tratamentos utilizados foram constituídos por quatro níveis de inclusão de FA (0%, 10%, 15%, 20%). Os teores médios da matéria seca nas silagens de capim-mombaça diferiram em função dos níveis do farelo de algodão, com variação de 22,69 a 31,93. Os teores da proteína bruta variaram de 12,51 a 22,45, e foram observadas diferenças significativas, ao mesmo tempo em que promoveu redução nos teores de fibras insolúveis em detergente neutro e fibras insolúveis em detergente ácido, mantendo assim dentro dos padrões recomendados, com destaque para o 20% de FA que apresentou maior nível e menores perdas por gases e efluentes. Os teores do potencial hidrogeniônico (pH) variaram de 4,88 a 5,17. Os teores de nitrogênio amoniacal (N-NH3), ficaram dentro dos parâmetros aceitáveis com 1,30% a 2,59%. Os teores médios de carboidratos solúveis variaram entre 4,60% a 8,90%, não havendo diferença significativa entre os níveis 10% e 15% de FA (P>0,05). Os teores de ácido lático, acético, propiônico e butírico variaram de 0,2682 a 1,5482; de 0,1759 a 0,3216; de 0,0114 a 0,0241 e de 0,0012 a 0,00162 respectivamente, e apresentou diferença estatística (P>0,05) entre os níveis de farelo de algodão. A degradabilidade “in situ” da matéria seca (MS) proteína bruta (PB) fibra insolúvel em detergente neutro (FDN) e fibra insolúvel em detergente ácido (FDA), foram significativamente influenciados pelos níveis de inclusão do farelo de algodão (P<0,05), tendo em destaque a inclusão do nível 20% do farelo de algodão que apresentou teores significativos de desaparecimento na MS, PB, FDN e FDA, mostrando ser o nível aceitável de farelo de algodão como adição para o capim-mombaça.

A sociedade está cada vez mais exigente com relação à qualidade dos produtos consumidos e se preocupa com os benefícios para a saúde. Neste contexto, objetivou-se avaliar o efeito da inclusão de níveis de óleo de canola na dieta de vacas sobre amanteiga e muçarela, buscando produtos mais saudáveis para o consumo humano. Foram utilizadas 18 vacas Holandesas, em estágio intermediário de lactação, com produção média de 22 (± 4) Kg de leite/ dia, as quais foram distribuídas em dois quadrados latinos 3x3 contemporâneos e receberam as dietas experimentais: T1- Controle (0% de inclusão de óleo); T2- 3% de inclusão de óleo de canola e T3- 6% de inclusão de óleo de canola. O perfil lipídico foi determinado através de cromatografia gasosa, além da avaliação de qualidade nutricional, realizada através de equações utilizando os ácidos graxos obtidos no perfil lipídico, análises físico-químicas determinadas pela metodologia do Instituto Adolfo Lutz e análises microbiológicas. Houveram problemas durante processamento do leite, gerando alterações de tecnologia de fabricação do produto manteiga, obtendo-se outro produto, o creme de leite, ao invés de manteiga, além de prejuízos na qualidade microbiológicas do creme de leite e muçarela. A inclusão de óleo de canola na dieta em lactação reduziu quadraticamente os ácidos graxos de cadeia curta e proporcionou aumento quadrático dos ácidos graxos de cadeia longa, dos ácidos graxos insaturados e ácidos graxos monoinsaturados na muçarela. A relação ácidos graxos saturados/ ácidos graxos insaturados (AGS/ AGI) e a relação ômega-6/ômega-3, assim como os índices de aterogenicidade e trombogenicidade, na muçarela, reduziram linearmente 25,68%, 31,35%; 32,12% e 21,78%, respectivamente, quando comparando T1 e T3. No creme de leite, houve redução linear dos ácidos graxos de cadeia curta e média, bem como, os ácidos graxos saturados e a relação ácidos graxos saturados/ ácidos graxos insaturados (AGS/ AGI) em 41,07%; 23,82%; 15,91% e 35,59%, respectivamente, enquanto os ácidos graxos de cadeia longa, ácidos graxos insaturados e ácidos graxos monoinsaturados aumentaram linearmente 41,40%; 28,24% e 32,07%, nesta ordem, quando comparando T1 com T3. Os índices de aterogenicidade e trombogenicidade reduziram de forma linear, enquanto o índice h/H (razão ácidos graxos hipocolesterolêmicos e hipercolesterolêmicos) aumentou linearmente. A composição físico-química de ambos derivados e o rendimento da muçarela não apresentaram efeito significativo com a inclusão do óleo de canola, exceto a proteína bruta da muçarela que apresentou aumento linear e a gordura do creme de leite que apresentou efeito quadrático. As análises microbiológicas mostram contagens muito elevadas de microrganismos, sugerindo que os produtos não apresentam qualidade microbiológica, decorrente da ausência do processo de pasteurização do creme e da baixa eficiência do tratamento térmico aplicado ao leite destinado a produção da muçarela. Conclui-se que a adição de óleo de canola na dieta de vacas lactantes proporciona muçarela e creme de leite mais saudáveis para o consumo humano, pois apresentaram perfil lipídico mais rico em ácidos graxos insaturados, além da série ômega-3 e ácido oleico, entretanto, devido a problemas de processamento, estes produtos obtidos, não estão aptos ao consumo devido à ausência de qualidade microbiológica. / Society is increasingly demanding with regard to the quality of the products consumed and worries about the health benefits. In this context, the objective was to evaluate the effect of inclusion of canola oil levels in cows diet on amanteiga and mozzarella, seeking healthier products for human consumption. 18 Holstein cows were used in middle stage of lactation, with average production of 22 (± 4) kg of milk / day, which were distributed in two 3x3 squares contemporary Latin and received the experimental diets: T1- control (0% of inclusion oil); T2 3% inclusion of canola oil and T3 6% canola oil inclusion. The lipid profile was determined by gas chromatography, in addition to evaluation of nutritional quality, performed using equations using fatty acids obtained in the lipid profile, physical and chemical analysis determined by the methodology of the Institute Adolfo Lutz and microbiological analysis. There were problems during processing of milk, generating fabrication technology changes butter product to give another product, the cream instead of butter, as well as losses in the microbiological quality of milk cream and mozzarella. The canola oil inclusion in the diet of lactating quadratically reduced the short-chain fatty acids and yielded quadratic increase in long-chain fatty acids, unsaturated fatty acids and monounsaturated fatty acids in the mozzarella. The ratio saturated fatty acid / unsaturated fatty acids (SFA / UFA) and the ratio omega-6 / omega-3 as well as the contents of atherogenicity and thrombogenicity in mozzarella, linearly decreased 25.68%, 31.35%; 32.12% and 21.78%, respectively, when comparing T1 and T3. In cream, there was a linear reduction of the fatty acids of short and medium chain, as well as saturated fatty acids and the ratio saturated fatty acid / unsaturated fatty acids (SFA / UFA) in 41.07%; 23.82%; 15.91% and 35.59% respectively, while long chain fatty acids, unsaturated fatty acids and monounsaturated fatty acids 41.40% increased linearly; 28.24% and 32.07%, in that order, when comparing T1 to T3. The index atherogenicity and thrombogenicity reduced linearly, while the ratio h / H (ratio hypocholesterolemic hypercholesterolemic fatty acids) increased linearly. The physical and chemical composition of both derivatives and the income of mozzarella no significant effect with the inclusion of canola oil, except the crude protein of mozzarella that showed a linear increase and fat cream which showed a quadratic effect. Microbiological analyzes show very high scores of microorganisms, suggesting that the products do not present microbiological quality, due to the absence of the cream pasteurization process and low efficiency of the thermal treatment of the milk for the production of mozzarella. We conclude that the addition of canola oil in the diet of lactating cows provides mozzarella and healthier cream for human consumption, as presented richer lipid profile in unsaturated fatty acids, as well as omega-3 series and oleic acid, however because of processing problems, the products obtained are not apt for consumption due to the lack of microbiological quality.

The aim of this study was to evaluate the Small Ruminant Nutrition System (SRNS) model’s performance predictions for lambs under South African conditions using growth and body composition data of early- (Dorper) and late-maturing (South African Mutton Merino), indigenous sheep breeds. The Cornell Net Carbohydrate and Protein System (CNCPS) biological model has consistently been modified to include recent information. This has led to the development of the SRNS model, but up to now the SRNS model has only been validated with European sheep breeds under European conditions. Thirty two Dorper, 16 male and 16 female lambs, and 36 South African Mutton Merino, 18 male and 18 female lambs, were fed a grower diet for the experimental period of 60 days. Three groups of lambs of each breed were slaughtered as the lambs reached pre-determined target weights. The first group of 24 animals (slaughter group 1) was slaughtered at the onset of the experiment at a live weight of 20 kg. With the second group (slaughter group 2) the South African Mutton Merinos were slaughtered at an average weight of 35 kg and the Dorpers at an average weight of 30 kg. The last group (slaughter group 3) had an average weight of 50 kg for the South African Mutton Merinos and 40 kg for the Dorpers at slaughter. Using the data from this trial, predictions of the average daily gain (ADG), feed intake (DMI), empty body gain and the composition of the empty body gain were used to evaluate the model. The animals were divided into three slaughter groups, based on growth stage, for the determination of body composition data. Energy value of gain (EVG), fat and protein content on a shrunk and empty body weight basis were compared with the corresponding values predicted by the SRNS. Growth composition of the lambs was determined by dividing them into two growth periods. Average daily gain and DMI were evaluated in the experiment, and results compared to the mean ADG and DMI predictions obtained from the SNRS model. Two different equations were compared to estimate EVG and two sets of coefficients were also compared for the EVG. Five different equations were compared to estimate the efficiency of conversion of metabolisable energy (ME) to net energy (NE) for gain, kg. The correction factor to adjust for the increase in the size of the visceral organs as nutrient intake increases and the coefficient for the effect of gender on maintenance requirements were tested for relevance of use in the SRNS. Overall, based on these evaluations it appears that the original SRNS model gave the best predictions when compared to any of the modifications tested. With regards to ADG the model over-predicts the requirements of the lambs in the early growth stage and under-predicts the requirements of the lambs in the later growth stage. The DMI predictions that were made using the original SRNS were accurate. The evaluation of the SNRS predictions in relation to the composition of gain indicated that this model over-predicted both the fat and the protein content of gain. The predictions were accurate, however the precision was low. The low precision was probably due to the lack of variation in the measured range of fat and protein content of gain. Before field application further studies and adjustments to the SRNS model is required, especially with regard to predictions on the fat and protein content of gain and over or under predictions of ADG during different growth stages of Dorper and South African Mutton Merino lambs. / Dissertation (MSc)--University of Pretoria, 2013. / gm2014 / Animal and Wildlife Sciences / unrestricted

Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2011. / Includes bibliography. / ENGLISH ABSTRACT: Forages are the main feed components in ruminant production systems for the reason that they are often the major source of energy available to the animal. However, only 10 to 35% of energy intake is available as net energy because the digestion of plant cell walls is not complete. This can significantly affect livestock performance and profits in production systems that use forages as a major source of nutrients of the diet. As a result of low and variable nutritive values of forage feedstuffs, attempts to improve ruminal fibre degradability have been an ongoing research topic. The use of exogenous fibrolytic enzymes (EFE) has been proposed as means to improve forage digestibility. Positive results with regard to rumen forage digestibility and other animal production traits have consequently been obtained due to increased rumen microbial activity following EFE addition in ruminant diets. Two EFE (Abo 374 and EFE 2) and one commercial yeast preparation were firstly identified and selected for their potential to improve the cumulative gas production (GP) at 24 hours of a range of feed substrates using the in vitro GP system as a screening step to identify the superior EFE products. The different feed substrates were lucerne hay, wheat straw, wheat straw treated with urea and a commercial concentrate diet. An in vitro experiment was undertaken on these four different substrates in order to evaluate the two EFE and the yeast preparation. This was to identify the most promising EFE capable of producing a significant effect on feed digestibility using organic matter digestibility (in vitro true digestibility) and fermentation characteristics (in vitro GP system). Results from the in vitro evaluation showed that EFE significantly enhanced in vitro DM degradability and GP profiles (P < 0.05). Abo 374 enzyme showed potential to increase in vitro microbial protein synthesis (MPS) of GP residues of the concentrate diet. In addition, no correlation was found between the in vitro MPS and the 48 hours cumulative GP of all the tested substrates (P < 0.05; R2 < 0.30). Treatments were found to increase in vitro MPS, feed degradability and the cumulative GP of different quality forages and the concentrate diet, with Abo 374 being the best treatment (P < 0.05). However in vitro responses of EFE were variable depending on the energy concentration and chemical composition of different substrates. Variation in MPS was mostly due to the low recovery of purine derivates with the purine laboratory analysis. On the basis of these results, Abo 374 was selected and consequently further tested in another in vitro and in situ trial using a mixed substrate of lucerne hay and wheat straw. Abo 374 significantly improved the cumulative GP, in vitro DM and NDF disappearance of the mixed substrate (P < 0.05). In addition, no correlation was found between the in vitro MPS and the cumulative GP at 48 hours (P = 0.68; R2 < 0.25). The in situ disappearance of feed nutrients (DM, NDF and CP) with Abo 374 was similar to the control. The lack of significance of disappearance was probably due to the small number of sheep used in the study and the relatively high coefficient of variation associated with measuring ruminal digestion. Abo 374 significantly increased the in situ MPS (P = 0.0088) of the mixed substrate of lucerne hay and wheat straw. Evidence of the increased MPS and both in vitro and in situ disappearance of DM and NDF resulted from the Abo 374 activity during either the pre-treatment or the digestion process. The addition of Abo 374 to the mixed substrate of lucerne hay and wheat straw appeared to have been beneficial for microbial colonization of feed particles as a result of the increased rumen activity. It could be speculated that the primary microbial colonization was thus initiated, leading to the release of digestion products that attract in return additional bacteria to the site of digestion. This EFE may be efficient to produce some beneficial depolymerisations of the surface structure of the plant material and the hydrolytic capacity of the rumen to improve microbial attachment and the feed digestibility thereafter. Therefore, the mechanism of action by which Abo 374 improved the feed digestion can be attributed to the increased microbial attachment, stimulation of the rumen microbial population and synergistic effects with hydrolases of ruminal micro-organisms. With regard to these findings, the addition of EFE in ruminant systems can improve the ruminal digestion of DM, NDF and CP to subsequently enhance the supply of the metabolizable protein to the small intestine. Key words: crude protein (CP), exogenous fibrolytic enzymes (EFE), dry matter (DM), gas production (GP), neutral detergent fibre (NDF), microbial protein synthesis (MPS). / AFRIKAANSE OPSOMMING: Ruvoere is die hoof-voerkomponent in herkouer produksiesisteme aangesien dit dikwels die vernaamstebron van energie aan herkouer is. Slegs 10 tot 35% van die energie-inname is beskikbaar as netto-enrgie, omdat die vertering van selwande onvolledig is. Dit kan die prestasie en profyt in produksiesisteme drasties beïnvloed waar ruvoere as ’n hoofbron van nutriënte in die dieet gebruik word. Aangesien die nutriëntwaarde van ruvoere laag is en baie varieer, is navorsing vir verbeterde ruminale veselvertering steeds ’n voorgesette onderwerp. Dit is voorgestel dat eksogeniese fibrolitese ensieme (EFE) gebruik kan word vir verbeterde ruvoervertering. Positiewe resultate in ruminale ruvoerverterig en ander diereproduksie-eienskappe, is verkry as gevolg van toenemende rumen mikrobiese aktiwiteit na EFE aanvulling in herkouerdiëte. Twee EFE’s (Abo 374 en EFE 2) en `n gisproduk is geïdentifiseer en geselekteer vir hul potensiaal om die kumulatiewe gasproduksie (GP) na 24 uur met ’n reeks voersubstrate te verbeter met die gebruik van die in vitro GP sisteem as seleksiemetode om die superieure EFE produkte te identifiseer. Die verskillende ruvoersubstrate was lusernhooi, koringstrooi, ureumbehandelde koringstrooi en ’n kommersiële konsentraatdieet. ’n In vitro eksperiment was onderneem om die vier verskillende substrate te gebruik om die twee EFE’s en gisproduk te evalueer. Hierdeur sou die belowendste EFE’s identifiseer kon word wat ’n betekenisvolle effek op ruvoervertering het. Die vertering van ruvoer sal bepaal word deur organiese materiaal vertering (in vitro ware vertering), asook fermentasie-eienskappe (in vitro GP sisteem). Resultate van die in vitro evaluering het getoon dat EFE’s in vitro DM degradering en GP profiele verbeter. Dit blyk dat die Abo 374 ensiem ’n potensiële toemame in in vitro mikrobiese proteïensintese (MPS), soos bepaal deur die GP oorblyfsels van konsentraat diëte, tot gevolg gehad het. Daar was geen korrelasie tussen die in vitro GP en MPS van al die proefsubstrate nie. Dit blyk dat die behandelings ’n toename in in vitro GP, MPS en ruvoerdegradeerbaarheid van lae kwaliteit ruvoer- en konsentraatdiëte gehad het, waar Abo 374 die beste behandeling was. Die in vitro reaksies van die EFE’s was egter wisselend, afhangende van die energiekonsentrasie en die chemiese samestelling van die verskillende substrate. Variasie van MPS was meestal as gevolg van die lae herwinning van purienderivate tydens die purienanalise. Op grond van dié resultate, is Abo 374 geselekteer om verdere toetse in ander in vitro en in situ proewe te doen. Die substraat wat gebruik is, was ’n 1:1 mengsel van lusernhooi en koringstrooi. Abo 374 het die kumulatiewe RP, in vitro DM en NBV verdwyning van die gemengde substraat verbeter. Boonop is geen korrelasie tussen die MPS en in vitro GP gevind nie. In situ verdwyning van DM, NBV en RP was hoër vir Abo 374, maar nie betekenisvol nie. Die gebrek aan betekenisvolle verdwynings mag die gevolg wees van die klein hoeveelheid skape wat in die proef gebruik is, asook die relatiewe hoë koëffisient van variasie wat gepaard gaan met die bepaling van ruminale vertering. Abo 374 het die in situ MPS betekenisvol verhoog. Verhoogde MPS en in vitro en in situ verdwyning van DM en NBV is waargeneemwaarskynlik as gevolg van die aktiwiteit van Abo 374 gedurende die voorafbehandeling óf die verterings proses. Die byvoeging van Abo 374 tot die gemengde substraat van lusernhooi en koringstrooi blyk om voordelig te wees vir mikrobiese kolonisering van voerpartikels as gevolg van ’n toename in rumenaktiwiteit. Die primêre mikrobiese kolonisering het waaarskynlik gelei tot die vrystelling van verteringsprodukte wat addisionele bakterieë na die plek van vertering lok. Die EFE mag geskik wees vir voordelige depolimerisasie op die oppervlakstruktuur van die plantmateriaal, asook verbeterde hidrolitiese kapasiteit van die rumen om sodoende mikrobiese aanhegting, asook ruvoervertering te verbeter. Dus, Abo 374 se meganisme van aksie wat verbeterde ruvoervertering tot gevolg het, kan toegeskryf word aan `n verhoogde mikrobiese aanhegting, stimulering van die rumen mikrobiese populasie en die sinergistiese effek met hidrolases van rumen mikroörganismes. Ten opsigte van die bevindings, kan die byvoeging van EFE in herkouersisteme ruminale vertering van DM, NBV en RP verbeter, wat dan daaropvolgend die dunderm met meer metaboliseerbare proteïn sal voorsien. Sleutelwoorde: eksogene fibrolitiese ensieme (EFE), droëmaterial (DM), ruproteïen (RP), neutraal bestande vesel (NBV), mikrobiese proteïensintese (MPS), gasproduksie (GP).