Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references (leaves 80-89). Also available on the Internet.

Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references (leaves 80-89). Also available on the Internet.

Three duodenally cannulated lactating Holstein cows fed cotton-seed meal (CSM), corn gluten meal (CGM) or blood meal (BM) as protein supplement were used in a 3 x 3 Latin Square experiment to determine microbial crude protein (MCP) in duodenal digesta. Diets, formulated to contain 15% crude protein (CP) on a dry matter basis, consited of 60% concentrate, 31% corn silage and 9% alfalfa hay. Chromium oxide was employed as flow marker. Microbial protein fraction of digesta CP (MCP/DCP) was estimated by three microbial markers: ¹⁵N, diaminopimelic acid (DAP) and ribonucleic acid (RNA). The isotopic method gave the most reliable results. Variability was higher with DAP and RNA. Results from RNA were lower (P < .01) and unreasonable. Based on ¹⁵N, MCP/DCP differed among treatments (P < .10) with means of 61.5, 59.4, and 50.0% for CSM, CGM, and BM, respectively, but differences were not significant for absolute amounts of total CP and MCP in duodenal digesta.

No description available.

Six Angus steers were used in a series of three metabolism trials to study the effect of energy concentration on nitrogen metabolism and digestibility. The experimental design consisted of two randomly selected 3 x 3 Latin squares. Three fattening rations were ted which contained 1133, 1164 and 1222 kcal. digestible energy per lb. feed and 12.18, 12.51 and 12.29% crude protein, respectively. The rations were composed of 10% grass hay, shelled corn, corn cobs and cottonseed meal. An attempt was made to equalize calcium and phosphorus contents. Vitamins A and D were added at the rate or 30,000 I.U. and 3750 I.U. per steer per day, respectively. Energy concentration was varied by changing the proportions of shelled corn and corn cobs. Digestible and metabolizable energy and TDN were all significantly increased with each increase in energy concentration. Digestible energy concentration of feed had no significant effect on nitrogen retention. Biological value waa higher for the medium energy ration than for the low or high energy rations. The quadratic effect was significant (P < .05). The apparent digestibilities of crude protein and ether extract were not influenced by energy concentration. Digestibility of' dry matter, organic matter and NPE significantly increased and digestibility of crude fiber significantly decreased with each increase in energy concentration. / Master of Science

The effects of three fertilization rates of N (0, 112 and 224 kg/ha) as ammonium nitrate and S (0, 34, and 67 kg/ha) as calcium sulphate on yield, chemical composition, digestibility and palatability of orchardgrass (Dactylis glomerata L.) , were studied in a field experiment. Treatments were applied in a randomized block design with a 3x3 factorial arrangement of treatments with four replications. Hay was harvested on 18 Aug. 1982 and fed to sheep in metabolism trials. One half of the initial amount of fertilizer was reapplied and forage was stockpiled. Stockpiled growth was ensiled on 6 Nov. 1982 and was fed to sheep in palatability trials. Fertilizer was reapplied at the initial rates on 27 Apr. 1983 and yield and mineral concentrations were determined on 6 June 1983. Dry matter yield increased in response to N (P<0.01). Nitrogen fertilization decreased NDF (P<0.05) ADF, cellulose (P<0.01) and total S (P<0.01) and increased nitrate-N (P<0.01) in hay and stockpiled growth. In stockpiled growth S increased ADF ( P<0.05) and cellulose quadratically ( P<0.001) at the 34 kg/ha rate. Sulphur increased ( P<0.05) No₃-N in hay but decreased (P<0.05) it in stockpiled growth. The N:S ratio was increased (P<0.01) by N fertilization and decreased (P<0.05) by S fertilization. Nitrogen and S had a quadratic effect (P<0.0001) on lactic acid and water-soluble carbohydrates in silage. Digestibility or palatability of silage was not influenced by N or S. / Master of Science

The effects of red clover (Trifolium pratense, L.), three levels of N (0, 224 and 448 kg•ha⁻1•yr⁻1, as a split application) and two levels of S (0 and 34 kg•ha⁻1•yr ) on the chemical composition and dry matter digestibility of an orchardgrass (Dactylis glomerata, L.) sward were studied. The treatments were replicated three times in a randomized block design with a split-plot arrangement of treatments. Crude protein content, in vitro dry matter digestibility and dry matter yield were increased (P<. 01) with increasing levels of N. Increasing levels of N decreased (P<.05) S content of orchardgrass. The inclusion of red clover did not have any significant effect on the components analyzed, probably due to a low proportion of red clover (approximately 8%) in the mixed sward. Application of S increased ( P<.05) the S content of orchardgrass and decreased N-to-S ratio at all levels of N application. Application of S increased (P<.05) the crude protein and in vitro dry matter digestibility, whereas neutral detergent fiber, lignin and hemicellulose were decreased (P<. 05). Nitrogen fertilization had a quadratic effect (P<.05) on in vivo digestibility of dry matter, acid detergent fiber and hemicellulose and a linear effect (P<.001) on apparent digestibility of crude protein. Inclusion of red clover increased (P<.01) in vivo digestibility of dry matter and hemicellulose, and decreased (P<.01) digestibility of acid detergent fiber and lignin. Application of S had no direct effect on in vivo digestibility of orchardgrass. A linear interaction (P<.01) between N and S was observed for dry matter and crude protein digestibility. Rumen fluid ammonia-N was increased (P<.05) and butyric acid concentration was decreased (P<.05) linearly by N fertilization. / Master of Science

Made available in DSpace on 2015-03-26T13:55:23Z (GMT). No. of bitstreams: 1 texto completo.pdf: 458453 bytes, checksum: 52841bfa7a70fd9ab10f120499d2f3c2 (MD5) Previous issue date: 2009-01-05 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / We evaluated the effect of four levels of mixing urea:ammonium sulfate (9:1) (Urea) on sugarcane (0, 0.4, 0.8 and 1.2%, fed basis) on consumption, on the intake and diet digestibility, production performance, metabolism of nitrogenous compounds and economy of diets in dairy cows producing less than 15 kg/day. We used 12 Holstein cows distributed in three 4x4 Latin squares. Diets were formulated to be isonitrogenous initially containing 12.5% crude protein, dry matter basis. The concentrated feed has been supplied in proportion to the milk production, making it a ratio of 1 kg for every 3 kg of milk. The sugarcane used had 21.9 brix. No effect of urea level in cane sugar on the intake and digestibility of dietary constituents, as well as on the production and composition of milk. It was found that the increase in the level of urea in sugar cane increases (P < 0.05) linearly the concentration of nitrogen-urea at the plasma, urinary excretion of nitrogen-urea (NUU in g/day) and the contribution of nitrogen-urea in the urinary excretion of nitrogen and reduce (P < 0.05) milk production per unit of nitrogen excreted in the urine. Although there wasn't detected significant effects (P > 0.05) for urinary excretion of nitrogen (UN) and nitrogen balance (NB), there was an increase of 50.3% on the UN and the consequent reduction 112.8% for the BN with increasing from 0 to 1.2% urea in sugarcane. These results demonstrate that even using sugarcane with high sugar content (50.5% of CNFcp, DM basis), the increased level of urea extends ureogênese and losses of nitrogen (N) in urine, reducing the efficiency of use of N, increasing energy expenditure and environmental liability. From the sensitivity analysis of the balance with the price of urea, it was found that the use of the same is feasible when the price is equal to or less than R$ 2.0/kg, equivalent to 2.17 times the price of kg of soybean, fed basis. In addition, it was found that regardless of the price range between R$ 0.40 to R$ 2,0/kg, the urea level that maximizes the balance with supply remains at 1.20%, fed basis of sugarcane. / Avaliou-se o efeito de quatro níveis da mistura de uréia:sulfato de amônio (9:1) (uréia) na cana-de-açúcar (0; 0,4; 0,8 e 1,2%, base da matéria natural) sobre o consumo, sobre o consumo e digestibilidade da dieta, desempenho produtivo, metabolismo de compostos nitrogenados e economicidade das dietas em vacas leiteiras com produção abaixo de 15 kg/dia. Utilizou-se 12 vacas da raça Holandesa, distribuídas em três quadrados latinos 4 × 4. As dietas foram inicialmente formuladas para serem isonitrogenadas contendo 12,5% de proteína bruta, base da matéria seca. A ração concentrada foi fornecida proporcional à produção de leite, perfazendo-se uma relação de 1 kg para cada 3 kg de leite produzido. A cana-de-açúcar utilizada apresentou 21,9 oBrix. Não houve efeito do nível de uréia na cana-de-açúcar sobre o consumo e coeficiente de digestibilidade dos constituintes da dieta, bem como sobre a produção e composição do leite. Verificou-se que o aumento no nível de uréia na cana aumenta (P<0,05) linearmente a concentração de nitrogênio-uréico no plasma, a excreção urinária de nitrogênio-uréico (NUU, em g/dia) e a contribuição do nitrogênio-uréico na excreção urinária de nitrogênio, além de reduzir (P < 0,05) a produção de leite por unidade de nitrogênio excretado na urina. Apesar de não terem sidos detectados efeitos significativos (P > 0,05) para a excreção urinária de nitrogênio (NU) e para o balanço de nitrogênio (BN), verificou-se aumento de 50,3% na NU e, conseqüente, redução de 112,8% no BN com o aumento de 0 para 1,2% de uréia na cana. Esses resultados demonstram que mesmo utilizando-se cana-de-açúcar com alto teor de açúcar (50,5% de CNFcp, base da MS), o aumento do nível de uréia amplia a ureogênese e as perdas de compostos nitrogenados (N) na urina, reduzindo a eficiência de utilização dos N, elevando-se o gasto energético e o passivo ambiental. A partir da análise de sensibilidade do saldo com alimentação ao preço da uréia, verificou-se que o uso da mesma é viável quando o preço for igual ou inferior à R$ 2,0/kg, o que equivale a 2,17 vezes o preço do kg do farelo de soja, base da matéria natural. Em adição, verificou-se que independente da faixa de preço entre R$ 0,40 a R$ 2,0/kg, o nível de uréia que permite maximizar o saldo com alimentação permanece em 1,20%, base da matéria natural da cana-de-açúcar.