Navigation/Menü: Links auf weitere Seiten dieser Website
|Experimentelle Untersuchungen zu fütterungsabhängigen Einflussfaktoren auf die Ergebnisse des Glukosetoleranztests bei Jungbullen, Ochsen und Färsen|
|Main title||Experimentelle Untersuchungen zu fütterungsabhängigen Einflussfaktoren auf die Ergebnisse des Glukosetoleranztests bei Jungbullen, Ochsen und Färsen|
|Title variations||Experimental examination of feeding-based influence on results of the glucose-tolerance-tests with young bulls, oxen and heifers|
Place of birth: Neubrandenburg
|1. Referee||Univ.-Prof. Dr. R. Staufenbiel|
|Further Referee(s)||Prof. Dr. L. Panicke
Univ.-Prof. Dr. H. Martens
|Keywords||Cattle, dairy cows, glucose tolerance test, animal feeding, animal breeding, sex differences|
|Classification (DDC)||630 Agriculture, Veterinary medicine|
|Summary||The partial selection of high milk yield in dairy breeding led to an enormous increase of milk yield but a series of sanitaryproblems within the dairy cattle stocks, too. Cows with high milk yield show a low level of insulin. Insulin occupies a central position in the metabolic arrangement for milk yield, fertility and metabolism by regulating metabolic arrangements. To counteract this trend in dairy cattle selection, the glucose-tolerance-test ought to determine the individual copability of metabolism regulation and with that to mark the breeding animal´s typ of metabolism. Thereby important additional information for breeding valuation could be determine but it is clear that the results of the glucose-tolerance-test are influenced by several factors. It exists a need for standartisation of the tests to get to reproducable results for a single animal and a whole group of animals.
This experimaental study examines the influences of of feeding, body condition and acute stress on the results of the glucose-tolerance-test under consideration of gender and age.
23 GTT´s have been carried out in a period of six months with six bulls, six oxen and six heifers. The animals were on average age of 9.2 months in the beginning and 14.8 months in the end of the tests. The whole period of six months was divided into three perservative phases. Each phase showed a rotation of feeding between food of high energetic potential (4-6 kg concentrated feed stuff plus 4 kg hay) and food with a low energy and protein (4 kg hay ad libitum). Addtionally a ratio with high protein and energy content rotated with a ratio of low energy and protein. Hunger, jealousy of food and accustical stress were used to create stress. A weekly determination of back fat thickness, live weight and a GTT was placed.
The bull´s glucose half-life is significantly more constant than the glucose half-life of oxen and heifers. The is no significant difference of glucose half-life between oxen and heifers but heifers showed the affinity of shortest glucose half-life. The glucose expanse-equivalent showed no difference between the genders and is therefore not usable for comparison of GTT-results between bulls and heifers. As expected heifers are significantly fatter than bulls and oxen. There are no existing differences of the back fat thickness between bulls and oxen. The energy-supply-level influences the GTT-result significantly. The influence of feeding acts indipendently rectified from gender. Low energy feeding shows significant shorter glucose half-life in comparison to a high energy feeding. The aprupt change of ratio from high to less energy lowered the glucose half-life significantly. With a change from low to to high energy ratios showed a decrease of glucose half-life after a few weeks. Along with this effect goes an excursive increase of the back fat thickness. The way of feeding influences the results of GTT significantly by using the data of body condition. The influence of the body condition on the GTT-results rises with the increase of overconditioning. In this interrelation it is necessary to differ between overconditioning and age-caused adiposis. A high content of protein in the ratio influences the GTT-results, too. Especially a simultanious lack of energy in the ratio leads to a decrease of the basal glucose concentration and an increase of the glucose half-life. An impact on the GTT-results by using acute stress turns out to be different and addicted to the moment of occurence. Thereby an untypical developing of the glucose concentration in GTT can be caused. With bulls the acute stress significantly extent the glucose half-life but with oxen and heifers it significantly decreases.
To get reproductable results the animals should be fed well balanced over at least four weeks before starting the test. Withal the body condition of the animals should range between mark 2.5 and mark 3.5 of the body-condition-score. Partial ratios and radical change of the ratio need to be avoided.
|Number of pages||167 S.|
|FU Department||Department of Veterinary Medicine|
|Year of publication||2009|
|Document type||Doctoral thesis|
|Authors comments||Mensch und Buch Verlag|
|Date of defense||2008-07-15|
|Created at||2009-03-20 : 01:14:03|
|Last changed||2010-02-19 : 03:07:11|