ISSN:0003-942X    

DOI:10.1080/17450399609381879

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Polioencephalomalacia (P.E.M.) in ruminants is often associated with high concentrate diets and rumen acidosis; this syndrome is classically related to a disturbance of the rumen metabolism of thiamin. Anin vitromodel using a semicontinuous system (RUSITEC) was used to investigate the effect of pH on microbial metabolism and on production of thiamin in the rumen. These effects were tested using either a natural diet (hay/wheat) or a semi‐synthetic one. Lowering the pH decreased total volatile fatty acids, methane and microbial nitrogen production. Molar proportions of VFA were modified by an increase in butyric, valeric and caproic acids. Microbial production of thiamin was comparable toin vivosynthesis but decreased when the diet was enriched with thiamin. The diet of the donors of inoculum had no effect on this metabolism. For all diets, lowering of pH did not reduce microbial production of thiamin. Thiaminase activity in the liquid phase of fermentors was very low and was not modified by pH. Thus lowering of pHin vitro, had no deleterious effect on microbial production of thiamin. Therefore, lowering of the rumen pH in acidotic conditions may not be a factor which promotes P.E.M.

ISSN:0003-942X    

DOI:10.1080/17450399609381880

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Four Jersey cows, fitted with ruminal and duodenal cannulas, were used to assess the specific effects of changes in ruminal pH that were induced by barley addition to a hay diet on ruminal fiber digestion. Cows received successively 100% unchopped cocksfoot hay (diet H), 65% hay and 35% pelleted ground barley (diet HB), and HB plus a continuous intraruminal infusion of bicarbonate salt solution (diet HBB). Cows were limit‐fed once daily at 7 kg of DM day‐1. The ruminal fractional passage rate of the liquid and hay was respectively estimated from a single administration of Cr‐EDTA and Eu labeled on hay fiber. Duodenal fiber flow was estimated both by the double marker method (Yb‐acetate/Cr‐EDTA) and by multiplying the fractional passage rate of Eu‐labeled hay by ruminal pool size. Barley supplement decreased ruminal NDF and ADF digestion compared with diet H, but passage rates of the solid and fluid fractions in the rumen were not affected. The depressive effect of barley supplement on in situ degradability of hay NDF and ADF decreased the degradation rates and increased the 72‐h undegradable fraction. Compared with diet HB, ruminal NDF and ADF digestion was improved with buffer supplementation but was less than that of diet H, eventhough ruminal pH was similar to that of diet H. Passage rates of the fluid and particle fractions were depressed and unaffected, respectively, with buffer addition. Higher in situ degradability of hay with the buffer supplement resulted in an increase in the 72‐h undegradable fraction, but the fractional degradation rate was unaffected.

ISSN:0003-942X    

DOI:10.1080/17450399609381881

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

In this study three different laboratory procedures were compared as predictors of net energy content of raw materials and compound feeds for ruminants. Laboratory measurements included an enzymatic technique (pepsin‐cellulase method) and a rumen fluid technique (Hohenheim gas test). An estimate based on crude nutrients only was also tested. A total of 98 feed samples with knownin vivodigestibility were available. By multivariate regression analysis equations for the prediction of the net energy content were calculated. The results suggest that in case of compound feeds for dairy the cellulase technique and the gas test are suitablein vitrotechniques. With both procedures the relationships between energy contents estimatedin vitroand energy contents measuredin vivoshowed residual errors of less than 4 percent. However for the evaluation of raw materials the gas test was superior. Compared to the cellulase technique the risk of extreme under‐ or overestimations is apparently reduced and this was found to be the case for own prediction equations as well as equations from literature. Crude nutrients proved to be very poor predictors for all feed samples.

ISSN:0003-942X    

DOI:10.1080/17450399609381882

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A bi‐factorial experiment was conducted to investigate the effect of enzyme supplements (200 mg RoxazymeRG per kg feed) and white lupins (35%, freshly harvested or stored) on concentrations of lipids in serum and lipoproteins as well as in chest and leg meat. Enzyme supplements had not any effect on concentrations of cholesterol, triglycerides and phospholipids in serum and lipoproteins and on concentrations of triglycerides and cholesterol in meat.

ISSN:0003-942X    

DOI:10.1080/17450399609381883

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

In an experiment with 405 Hisex white hens rations with 5–20 % low glucosinolate rapeseed (RS) or rape‐seed meal (RSM) of 00 quality were used. Feed intake, egg production, individual egg weight and live weight gain were reduced in hens fed 5–20% RS and 10–20% RSM. There was a positive correlation between the RS proportion in the ration and the thyroid weight as well as the iodine content of the thyroid. The relation between the iodine content related to one gram of thyroid and the RS proportion was not significant. There were not any significant differences between the RSM groups and the iodine content of the thyroid. The T3and T4concentrations in the blood plasma was independent of the RS‐ or RSM‐proportion in the diet.

ISSN:0003-942X    

DOI:10.1080/17450399609381884

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Two experiments, each following a two‐factorial design (2 × 2), were carried out using 12 and 13 male kids initially weighing about 10 kg. Concentrations per kg dietary dry matter were 10 vs. 4 g Ca and 4.5 vs. 2.0 g P in experiment 1 as compared to 10 vs. 17 g Ca and 4.2 vs. 2.5 g P in experiment 2, respectively.

ISSN:0003-942X    

DOI:10.1080/17450399609381885

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Annette Zeyner: Diätetik beim Pferd. Vet special. 175 S., 15 Abb., 23 Tab., Gustav Fischer Verlag Jena ‐ Stuttgart 1995. ISBN 3–334–60905–7

ISSN:0003-942X    

DOI:10.1080/17450399609381886

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:0003-942X    

DOI:10.1080/17450399609381878

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor