Master of Agribusiness / Department of Agricultural Economics / Jeffery R. Williams / Economically optimized ration formulations were used to test whether California dairy producers who implemented price risk management strategies on both the input and output sides achieved significantly higher net returns as measured by milk income minus feed costs compared to producers who bought feed and sold milk on the spot market. Two ration formulation models were developed, a least cost and a profit-maximization. The least cost method formulates a ration that meets the nutritional requirements of a lactating cow at the lowest possible cost for a given level of milk production. The profit maximization model incorporates into its algorithm a production function between net energy intake and milk production that increases at a decreasing rate. For today's high producing cows, after being supplied with enough energy to meet maintenance requirements, all additional energy is partitioned for milk production. Up to a certain point, depending on the price of milk and the price of feed, the cost of providing additional feed units is more than offset by the revenues derived by the extra milk produced from the larger quantities of feed consumed. The profit-maximization model used formulates a ration using both feed and milk prices where the cost of the last unit of feed provided is equal to the revenues of the last unit of milk produced. To compare returns, a ration program was designed that could either use spot or forward values for feed costs and milk price to economically optimize the ration on a weekly basis in the cow’s milk production cycle. To better gauge the impact of price volatility on both the input and output sides and to account for the extended nature of the forward contracts, the 305-day lactation cycle of a high producing cow over six successive cycles was used. The federal order Class III milk price was used for milk values and it was assumed that unless the producer engaged in some sort of forward contract, the milk price received was the monthly Class III value. To account for forward sales, the Class III futures contract traded at the Chicago Mercantile Exchange was used. For the feed prices, the ration model had a library of 16 different ingredients, 11 of which had forward and spot values. Similar to the output side, it was assumed that unless the producer engaged in some sort of forward contract the feed price used was the spot value averaged for each month. Most California dairy operators use some version of the least-cost method when formulating their rations. A large number also forward contract a significant portion of their feed as the concept of forward contracting feed is much more common in the western U.S. as compared to other regions in the country. Conversely, there has been little interest in locking in future milk prices as the tools for forward contracting are relatively new and many producers are not familiar with the mechanics. This helps explain the limited use of the profit-maximization model since milk prices are an integral part of this process. Results of this study show that producers who formulate using the profit-maximization model attain higher milk production and derive higher milk revenues, albeit with higher feed costs. Nonetheless, across every situation, that is whether one forward contracts feed, milk, or some combination thereof the profit-maximization model returned anywhere from $0.14 to $0.19 of milk revenues in excess of feed costs per hundredweight of milk as opposed to the least-cost method. For a producer milking 1,000 cows this represents another $50,000 to $70,000 of income per year. The results also show that whether least-cost or the profit-maximization method is employed, feed costs were lower when producers forward contract at least a portion of their needs. Milk prices, on the other hand, were lower relying on the spot market as opposed to either of the two forward milk contracting models that were developed. Finally, the variability of returns as measured by the coefficient of variability show less volatility in revenues when producers forward contract milk and less variability with input costs when producers forward contract feed.

Produtos de fracionamento da Farinha de Soja Desengordurada e Autoclavada foram administrados a ratos para avaliar ação na tireóide, em ensaios desde 7 até 84 dias de duração. Frações de baixo peso molecular, solúveis em água e acetona, quando avaliadas em ensaios agudos, de 24hs ou \"in vitro\", provocaram uma diminuição na captação de I-131. Porém, quando avaliados em rações, em experiências de até 84 dias de duração, mesmo em condições de restrição de iodo, não apresentaram efeito significativo. Por outro lado, identificou-se um fator, associado às frações de alto peso molecular, que induz, já a partir de 14 dias, quando administrado em rações com restrição em iodo, um aumento no peso da tireóide, redução na captação de I131, alterações na Síntese dos hormônios e seus precursores a nível glandular. Em ensaios mais longos (84 dias), provoca uma diminuição de T4 sérico e uma rarefação bastante significativa no colóide do folículo glandular. Por sua vez, a hidrólise de uma das frações de alto peso molecular, por pepsina e pancreatina, não é capaz de inativar a ação desse fator. O seu mecanismo de ação parece ser semelhante ao de substâncias que agem a nível de captação de iodo pela tireóide. / Defatted autoclaved soybean flour presented a water/acetone soluble fraction which is able to depress I-131uptake by rat thyroids tested in 24hs \"in vivo\" or in 3hs \"in vitro\" assays. When this fraction was given to rats in ration with either normal or deficient iodine content for periods from 7 to 84 days no significant action was detected. On the other hand a factor associated to the high molecular weight protein fraction was identified. The factor is active in rats starting from 14 days after ingestion, in rations with low iodine content producing: increase in thyroid weight, lowering of I-131 uptake, alteration on MIT/DIT, T3/T4 ratios and after 84 days of administration a significant reduction of serum T4 and a large decrease of the colloid content of follicle. Hydrolysis by pepsin or pancreatin does not eliminate the observed action. The mechanism of action of this factor seems to the related to a blockage of the iodine uptake.

Orientador: Danilo Domingues Millen / Resumo: O objetivo deste estudo foi avaliar a redução do tempo de adaptação à rações com alto teores de energia para bovinos Nelore canulados em confinamento com a utilização de virginiamicina (VM) como aditivo alimentar, em que foram avaliadas as seguintes variáveis: pH, temperatura, e potencial de óxido-redução do rúmen, taxa de desaparecimento, digestibilidade total e degradabilidade ruminal de nutrientes, seletividade da ração e comportamento ingestivo, produtos da fermentação ruminal, assim como dados de ingestão de matéria seca. O delineamento experimental foi em quadrado latino 5x5, e cada período durou 21 dias, com 7 dias de washout entre o final e o início de um novo período. Foram utilizados 5 bovinos inteiros, com peso vivo aproximado de 414.86 ± 21.71 kg e com 17 meses de idade. Neste estudo os animais foram divididos em cinco tratamentos: 1) Monensina (MON; 30 mg/kg) com adaptação por 14 dias; 2) MON (30 mg/kg) + VM (25 mg/kg) com adaptação por 14 dias; 3) VM (25 mg/kg) com adaptação por 14 dias; 4) VM (25 mg/kg) com adaptação por 9 dias; e 5) VM (25 mg/kg) com adaptação por 6 dias. Bovinos que consumiram apenas MON tiveram menor concentração de butirato (P=0,02) e maior concentração de propionato (P=0,04), quando comparados aos que consumiram VM e foram adaptados por 14 dias. E animais que consumiram VM e foram adaptados por 14 dias tiveram maiores proporções AGCC quando comparados com animais que consumiram VMMON (P= 0,05) e quando comparados com animais que consumiram... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The objective of this study was to evaluate the reduction of adaptation length to the high-energy diet offered to cannulated Nellore cattle using Virginiamycin (VM) as sole feed additive, in which the following variables were assessed: pH, temperature,and ox-redox potential of the rumen, rate of disappearance, total tract digestibility and rumen nutrient degradability, feed particles sorting and feeding behavior, ruminal fermentation end-products, as well as dry matter intake. It was adopted the experimental design in a 5 x 5 Latin square, where each period lasted 21 days, with 7-day washout between the end and the beginning of a new period. Were used 5 Nellore yearling bulls,with approximately 414.86 ± 21.71 kg of body weight and 17 mo-old. In this study, the animals were divided into five treatments: 1) MON (30 mg/kg) adapted by 14 days; 2) MON (30 mg/kg) + VM (25 mg/kg) adapted by 14 days; 3) VM (25 mg/kg) adapted by 14 days; 4) VM (25 mg/kg) adapted by 9 days and 5) VM (25 mg/kg) adapted by 6 days.Bovine animals that consumed only MON had lower concentration of butyrate (P = 0.02)and higher concentration of propionate (P = 0.04) when compared to those that consumed VM and were adapted for 14 days. Animals that consumed VM and were adapted for 14 days had higher AGCC ratios when compared to animals that consumed VMMON (P = 0.05) and when compared to animals that consumed only MON (P = 0.04). As the adaptation time increased for animals that consumed VM, the dry matter inta... (Complete abstract click electronic access below) / Mestre

Produtos de fracionamento da Farinha de Soja Desengordurada e Autoclavada foram administrados a ratos para avaliar ação na tireóide, em ensaios desde 7 até 84 dias de duração. Frações de baixo peso molecular, solúveis em água e acetona, quando avaliadas em ensaios agudos, de 24hs ou \"in vitro\", provocaram uma diminuição na captação de I-131. Porém, quando avaliados em rações, em experiências de até 84 dias de duração, mesmo em condições de restrição de iodo, não apresentaram efeito significativo. Por outro lado, identificou-se um fator, associado às frações de alto peso molecular, que induz, já a partir de 14 dias, quando administrado em rações com restrição em iodo, um aumento no peso da tireóide, redução na captação de I131, alterações na Síntese dos hormônios e seus precursores a nível glandular. Em ensaios mais longos (84 dias), provoca uma diminuição de T4 sérico e uma rarefação bastante significativa no colóide do folículo glandular. Por sua vez, a hidrólise de uma das frações de alto peso molecular, por pepsina e pancreatina, não é capaz de inativar a ação desse fator. O seu mecanismo de ação parece ser semelhante ao de substâncias que agem a nível de captação de iodo pela tireóide. / Defatted autoclaved soybean flour presented a water/acetone soluble fraction which is able to depress I-131uptake by rat thyroids tested in 24hs \"in vivo\" or in 3hs \"in vitro\" assays. When this fraction was given to rats in ration with either normal or deficient iodine content for periods from 7 to 84 days no significant action was detected. On the other hand a factor associated to the high molecular weight protein fraction was identified. The factor is active in rats starting from 14 days after ingestion, in rations with low iodine content producing: increase in thyroid weight, lowering of I-131 uptake, alteration on MIT/DIT, T3/T4 ratios and after 84 days of administration a significant reduction of serum T4 and a large decrease of the colloid content of follicle. Hydrolysis by pepsin or pancreatin does not eliminate the observed action. The mechanism of action of this factor seems to the related to a blockage of the iodine uptake.

Na presente dissertação foi desenvolvido um procedimento automático para a determinação de selênio em rações para animais doméstico digeridas em meio ácido. O método automatizado foi baseado no efeito catalítico do selênio(IV) na reação de sulfato de ferro amoniacal com EDTA em meio contendo NaNO3. O módulo de análise foi baseado no processo de multicomutação em fluxo. Tendo em vista que reação tem cinética lenta, o módulo de análise foi projetado com seis bobinas de reação acopladas em paralelo para permitir tempo de residência da zona de amostra em torno de cinco minutos, sem comprometer a freqüência de amostragem. Após a definição das variáveis de controle, amostras de rações para animais digeridas em meio de ácido nítrico/perclórico foram processadas. Os resultados referentes ao testes de adição de padrão apresentaram recuperação entre 95 e 109 %. Outras características importantes tais como desvio padrão relativo em torno de 2% (n = 8) e freqüência de amostragem de 60 determinações por hora foram observadas. / In this work it was developed an automatic procedure for the determination of selenium in ration for domestic animals digested in acidic medium. The automated method was based on the catalytic effect caused by selenium (IV) on the reaction of ammoniacal iron sulfate with EDTA in medium containing NaNO3. The analytical module was based on multicommuted flow process. Considering that the kinetic of reaction was slow, the analytical module was designed with six reaction coupled in parallel in order to allow that residence time of sample zone was increased up to 5 min without decrease of the analytical throughput. After definition of the system control variables, sample of animal ration mineralized in nitric/perchloric acid medium were processed. The results concerning to standard solution addition assays gave recoveries between the range of 95 % up to 109 %. Other profitable features such as a relative standard deviation of 2 % (n = 8) and an analytical throughput of 60 samples determination per hours were also achieved.

<p>Three studies were conducted to evaluate the nutritional value of different oat (Avena sativa) forage cultivars (Assiniboia, Bell and Baler) that were newly emerged cultivars as a result of extensive oat growing conditions in western Canada. A total tract digestibility trial using 24 sheep (n=6) in a completely random design was conducted to assess apparent digestibility of dry matter (DM), organic matter (OM), crude protein (CP), crude fat (EE), acid detergent fiber (ADF), neutral detergent fiber (NDF), hemicellulose, non-structural carbohydrate, acid detergent lignin (ADL), soluble crude protein (SCP), non-protein nitrogen (NPN) and neutral detergent insoluble crude protein (NDICP) in Assiniboia silage, Bell hay, Baler hay and Rosser (barley- Hordeum vulgare) silage. Rumen in situ degradability characteristics of DM, OM, CP, ADF and NDF were determined on Assiniboia silage, Bell hay, Baler hay and Rosser silage at 96 to 0 h using a Holstein cow fitted with a rumen fistula. A dairy production trial using 8 multiparous Holstein cows at 90±20 DIM averaging 41 kg d-1 milk yield, in a 2 × 3 switch-back design was conducted to compare the production response of the cows fed either 48 percent Assiniboia silage or Rosser silage (DM basis) in total mixed rations with the concentrate portion consisting mainly of rolled barley, canola meal and soy meal.</p> <p>Digestibility of DM, OM, NDF, NPN, NDICP and EE were not different for Assiniboia and Rosser silages. Digestibility of DM, NDF and ADF were similar for Baler hay and Rosser silage. Digestibility of hemicellulose, NSC and ADL were similar for all forages. Sheep voluntary intakes of DM, OM, NDF, ADF and EE, except CP were similar across the forages. Assiniboia silage provided more nutrients to the rumen than the hays due to the higher rumen disappearance and effective degradabilities of DM and CP, and lesser undegradable DM, CP, NDF and ADF (P<0.05). Estimated carbohydrate and protein fractions of Assiniboia and Rosser silages were similar. Assiniboia silage was typically comparable to Rosser silage whereas Baler hay was compatible to Bell hay which in contrast was chemically inferior to Baler hay in NDF and TDN content. An increase (8%, P<0.05) in milk fat percentage was observed in cows fed the Assiniboia diet. Milk protein and lactose percentages, and protein yield were higher (P<0.05) in the cows fed the Rosser diet. However, 3.5% fat corrected milk yields were similar. Milk fatty acids (FA) when Assiniboia diet was fed, showed a remarkable increase (P<0.05) in oleate percentage and yield while the others were not different. The increase in oleate content resulted in an increase (P<0.05) in unsaturated FA to saturated FA ratio. Therefore Assiniboia silage would be useful to increase unsaturated long chain milk fat content. It is concluded that Assiniboia silage could substitute for Rosser silage in dairy rations.</p>

<p>Three studies were conducted to evaluate the nutritional value of different oat (Avena sativa) forage cultivars (Assiniboia, Bell and Baler) that were newly emerged cultivars as a result of extensive oat growing conditions in western Canada. A total tract digestibility trial using 24 sheep (n=6) in a completely random design was conducted to assess apparent digestibility of dry matter (DM), organic matter (OM), crude protein (CP), crude fat (EE), acid detergent fiber (ADF), neutral detergent fiber (NDF), hemicellulose, non-structural carbohydrate, acid detergent lignin (ADL), soluble crude protein (SCP), non-protein nitrogen (NPN) and neutral detergent insoluble crude protein (NDICP) in Assiniboia silage, Bell hay, Baler hay and Rosser (barley- Hordeum vulgare) silage. Rumen in situ degradability characteristics of DM, OM, CP, ADF and NDF were determined on Assiniboia silage, Bell hay, Baler hay and Rosser silage at 96 to 0 h using a Holstein cow fitted with a rumen fistula. A dairy production trial using 8 multiparous Holstein cows at 90±20 DIM averaging 41 kg d-1 milk yield, in a 2 × 3 switch-back design was conducted to compare the production response of the cows fed either 48 percent Assiniboia silage or Rosser silage (DM basis) in total mixed rations with the concentrate portion consisting mainly of rolled barley, canola meal and soy meal.</p> <p>Digestibility of DM, OM, NDF, NPN, NDICP and EE were not different for Assiniboia and Rosser silages. Digestibility of DM, NDF and ADF were similar for Baler hay and Rosser silage. Digestibility of hemicellulose, NSC and ADL were similar for all forages. Sheep voluntary intakes of DM, OM, NDF, ADF and EE, except CP were similar across the forages. Assiniboia silage provided more nutrients to the rumen than the hays due to the higher rumen disappearance and effective degradabilities of DM and CP, and lesser undegradable DM, CP, NDF and ADF (P<0.05). Estimated carbohydrate and protein fractions of Assiniboia and Rosser silages were similar. Assiniboia silage was typically comparable to Rosser silage whereas Baler hay was compatible to Bell hay which in contrast was chemically inferior to Baler hay in NDF and TDN content. An increase (8%, P<0.05) in milk fat percentage was observed in cows fed the Assiniboia diet. Milk protein and lactose percentages, and protein yield were higher (P<0.05) in the cows fed the Rosser diet. However, 3.5% fat corrected milk yields were similar. Milk fatty acids (FA) when Assiniboia diet was fed, showed a remarkable increase (P<0.05) in oleate percentage and yield while the others were not different. The increase in oleate content resulted in an increase (P<0.05) in unsaturated FA to saturated FA ratio. Therefore Assiniboia silage would be useful to increase unsaturated long chain milk fat content. It is concluded that Assiniboia silage could substitute for Rosser silage in dairy rations.</p>

In this study, complex rolling technology is adopted to produce aluminum/copper clad metals . The aluminum alloy A1050 and the copper C1100 are used. The experimental plan : the roughness (RCu=3.5£gm¡ARAl=6.45£gm)¡A(RCu=1.0£gm¡ARAl =2.15£gm)¡A(RCu=0.35£gm¡ARAl=0.8£gm) the thickness ratio(tAl:tCu=3:1)¡A(tAl:tCu =2:2)¡A(tAl:tCu=1:3) reduction 60% and 70% are set. It shows that the influence of the thickness is more significant than the roughness on the curvature according to the experimental results. And the results of peeling tests show that the peeling strength for the reduction 70% is larger than that for 60%. And peel strength with the second time rolling is larger than that with only once. The average peeling strength of the specimen in the rolling direction is larger than that in the perpendicular direction. From the micro Vickers hardness tests , it is known that the larger of the reduction of copper is, the larger the micro Vickers hardness between the interface of the sheets is .

Jörg Bauerfeld Untersuchungen zur Prophylaxe der Gebärparese bei Kühen durch Verfütterung anionenangereicherter Rationen in der Trockenstehperiode Medizinische Tierklinik der Veterinärmedizinischen Fakultät der Universität Leipzig In einem Milchkuhbestand mit hoher Gebärpareseinzidenz wurden Untersuchungen zur Prophylaxe durch gezielte Steuerung der Dietary Cation-Anion-Difference (DCAD) in der Trockenstehperiode mittels Fütterung einer Anionenration (&#132;saure Salze&#147;) und zur Ermittlung einer optimalen Applikationsdauer durchgeführt. Dazu wurden Verlaufsuntersuchungen im Zeitraum von 6 Wochen (Wo.) ante partum (a.p.) bis 14 Tage (d) post partum (p.p.) zu den Parametern des Calcium-, Phosphor- und Säure-Basen-Haushaltes in Blut und Harn vorgenommen. Die DCAD der Futterration in der Trockenstehperiode, die an die Kontrolltiere (KT) verfüttert wurde, betrug +221,4 meq/kg TS. Durch Zusatz eines definierten Mineralstoffgemischs wurde die DCAD der Ration auf &#150;108,8 meq/kg TS abgesenkt und den Versuchstieren (VT) im Durchschnitt 36 d a.p. gefüttert. VT und KT hatten die absolut gleichen Haltungsbedingungen. Als Probanden dienten Kühe ab der 4. Laktation mit hoher Gepärparesegefährdung. Eine visuelle Körperkonditionsbewertung wurde 1 Wo. a.p. mittels Body Condition Scoring nach EDMONDSON et al. (1989) durchgeführt und ergab durchschnittliche Boniturnoten bei den VT von 3,8 ± 0,3 und bei den KT von 3,8 ± 0,2. Durch die Verfütterung der Anionenration in der Trockenstehperiode wurde mit 5 % bei den VT eine deutlich geringere Gebärparese-inzidenz als mit 47,5 % bei den KT erreicht. Puerperium und Milchleistung wurden günstig beeinflußt. Statistisch gesicherte höhere Konzentrationen bei ionisiertem Calcium (Cai), Gesamtcalcium (Cat), Ionisierungsgrad des Calciums und anorganischem Phosphat (Pa) im Blut wurden bei den VT gegenüber den KT nur unmittelbar nach der Kalbung (1 d p.p.) festgestellt. Beim Blut-pH-Wert fanden sich keine statistisch gesicherten Unterschiede. Die Erzeugung einer milden Azidose durch die Verfütterung der Anionenration ließ sich durch die Bestimmung des Harn-pH-Wertes nicht nachweisen. Zwischen VT und KT gab es hier über den gesamten Untersuchungszeitraum keine statistisch signifikanten Unterschiede. Erst durch Bestimmung der fraktionierten Netto-Säuren-Basen-Ausscheidung (NSBA), des Kreatinins und der errechneten Quotienten im Harn zeigte sich, daß im präpartalen Zeitraum bei den VT eine milde Azidose mit günstigem Einfluß auf den Calciumhaushalt erzeugt wurde. Die Azidität des Harnes ist bei den VT 2 und 1 Wo. a.p. und 1 d p.p. statistisch gesichert deutlicher ausgeprägt als bei den KT. Für den milden kompensierten Charakter der induzierten Azidose spricht, daß sich der Blut-pH-Wert über den gesamten Untersuchungszeitraum im physiologischen Bereich bewegte und Veränderungen im Calcium-Metabolismus erst unmittelbar unter der Geburt auftraten. Klinische Nebenwirkungen waren, bis auf eine gesteigerte Diurese in Einzelfällen, nicht zu verzeichnen. Zur Ermittlung einer optimalen Applikationsdauer der Anionenration wurden die VT in vier Gruppen zu je 10 Kühen unterteilt und diesen die Anionenration in unterschiedlicher Dauer a.p. gefüttert. Hier zeigte sich, daß in der Gruppe mit der kürzesten Applikationsdauer (3 Wo. a.p.) die beiden einzigen klinisch manifesten Gebärparesefälle bei den VT auftraten. Die Milchleistung in der Folgelaktation blieb deutlich unter der der anderen VG. Bei den Blutparametern zeigten sich statistisch signifikante Unterschiede nur beim Ionisierungsgrad des Calciums, der bei der Gruppe mit 3-wöchiger Applikationsdauer a.p. 1 d p.p. am niedrigsten war. Die Erzeugung der (milden) Azidose erfolgte bei dieser Gruppe 2 Wo. a.p. mit Beginn der Transitfütterung. Das bedeutet eine zusätzliche Belastung der Regulationssysteme des Säure-Basen-Haushaltes in diesem Zeitraum. Daraus ist zu schließen, daß eine kurze Applikationsdauer von 3 Wo. a.p. nicht die gute Wirksamkeit einer längeren zur Gebärpareseprophylaxe besitzt. Die übrigen drei Gruppen mit längerer Applikations-dauer wiesen bei den Blut- und Harnparametern keine statistisch signifikanten Unterschiede auf. Die Gruppe mit 5- bis 6-wöchiger Applikationsdauer wies bei den Blut- und Harnparametern die konstantesten Verhältnisse bzw. die kontinuierlichsten Veränderungen auf. Die 5- bis 6-wöchige Applikationsdauer der Anionenration a.p. stellt somit die beste Variante dar und gewährleistet, daß auch bei Kühen mit Abkalbung vor dem errechneten Geburtstermin eine ausreichende azidotische Wirkung auf den Calciumstoffwechsel gegeben ist. / Jörg Bauerfeld Investigations into the prophylaxis of parturient paresis in cows by administering anion-enriched rations during the dry period Large Animal Clinic for Internal Medicine, Faculty of Veterinary Medicine University of Leipzig In a dairy cow livestock with many incidences of parturient paresis, research was conducted in order to determine a prophylaxis strategy by purposefully controlling the Dietary Cation-Anion-Difference (DCAD) through administration of an anion ration (&#147;acidic salt&#148;) during the dry period and in order to determine the optimal length of application. Therefore the parameters of the calcium, the phosphor and the acid base state were investigated in blood as well as in urine for the period of time of 6 weeks before parturition (b.p.) and up to 14 days after parturition (a.p.). The DCAD of the food ration that was given to the control animals (CA) during the dry period amounted to + 221.4 meq/kg DM. By adding a well-defined amount of mineral mixture, the DCAD of the ration came down to -108.8 meq/kg DM and was fed to the test animals (TA) on average 36 days a. p. TA and CA were kept and fed under similar conditions. Cows starting from 4th lactation and at high risk of parturient paresis were used as test animals. A visual assessment of the body condition was carried out by means of the &#147;Body Condition Scoring&#148; by EDMONDSON et al. (1989) 1 week b.p., resulting in mean Bonitur marks of 3.8 ± 0.3 in the TA and 3.8 ± 0.2 in the CA. Because of the administration of the anion ration during the dry period markedly less incidences of parturient paresis occurred with 5 % in the TA, compared to the 47.5 % in the CA. Puerperium and milk yield were favourably influenced in the following lactation. Statistically confirmed higher concentrations in ionised calcium (Cai), total calcium (Cat), degree of ionisation of calcium and inorganic phosphate (Pa) were determined in the TA compared to the CA just after calving (1 day a.p.). Regarding the pH-value of blood, no statistically proven differences were found. The creation of a mild acidosis could not be verified through the determination of the pH-value of urine. Statistically the TA and the CA did not differ significantly during the period of the investigations. Only after determining the fractioned net acid base excretion, the creatinine and the quotients in urine a mild acidosis with a favourable effect on the calcium balance became noticeable in the test animals during the peripartal period. Compared to the CA, the acidity of urine is statistically proven and markedly distinctive 2 and 1 week b.p. and 1 day a.p.. The mild and compensated character of the induced acidosis is indicated by the pH-value in blood which varied within the physiological range during the whole period of investigations as well as the changes in the calcium metabolism occurring just after parturition. Except for diuresis in single cases, clinical side effects were not registered. Determining the optimal length of application, TA were divided into 4 groups with 10 cows each and the anion ration was given to these groups in varying periods b.p.. Evidently, the group with the shortest duration of application, 3 weeks, had the only two apparent incidences of parturient paresis in TA. Besides, the following lactation clearly lagged behind to those of the other TA. Regarding the blood parameters, the only statistically significant differences occurred in the degree of ionisation of calcium in blood, whereas the degree value 1 day a.p. was at its lowest in the group with the application period of 3 weeks. The mild acidosis was created in that group 2 weeks b.p. at the beginning of the transit feeding, which means that the regulating system of the acid base state was additionally strained during that period of time. Hence, a short application period of 3 weeks b. p. is less effective compared to a longer one in order to prevent parturient paresis. The other three groups with longer periods of application showed no statistically significant differences in blood and urine parameters. The group with the application period of 5 and 6 weeks showed in their blood and urine parameters the most balanced rates and continuous changes. The application of anion ration over a period of time between 5 and 6 weeks b. p. is consequently regarded to be the best option and insures even a sufficient acidotic effect on the Ca metabolism

Reproduction de : Thèse d'exercice : Médecine : Nancy 1 : 2002. / Thèse : 2002NAN11170. Titre provenant de l'écran-titre.