東華大學圖書館 |

Language: English

Help

回圖書館首頁

手機版館藏查詢

Back

Switch To: Labeled | MARC Mode | ISBD

Regulation of the ruminal environmen...

Mooney, Charles Steven.

Linked to FindBook

Google Book

Amazon

博客來

Regulation of the ruminal environment by lactating dairy cows.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Regulation of the ruminal environment by lactating dairy cows./
Author:	Mooney, Charles Steven.
Description:	288 p.
Notes:	Adviser: Michael S. Allen.
Contained By:	Dissertation Abstracts International67-10B.
Subject:	Agriculture, Animal Culture and Nutrition. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3236376
ISBN:	9780542908248

Regulation of the ruminal environment by lactating dairy cows.
Mooney, Charles Steven.

Regulation of the ruminal environment by lactating dairy cows. - 288 p.

Adviser: Michael S. Allen.

Thesis (Ph.D.)--Michigan State University, 2006.

The ruminal environment must be regulated for the health and productivity of ruminants. Sodium is the most abundant cation in the ruminal solution and is the most likely candidate as the regulated ion. Three experiments were conducted to evaluate the role of strong ions in the ruminal environment. If sodium compounds are infused into the ruminal solution, rumination time is reduced markedly, however, these infusions may generate ruminal conditions that are not representative of normal physiological or nutritional conditions. In the first experiment, we hypothesized that additional dietary sodium at normal concentrations would reduce rumination time of dairy cows. Additional dietary sodium decreased rumination time as did additional dietary potassium indicating that the general decrease in rumination was caused by a tonic increase in ruminal osmolality. Sodium is often added to lactating dairy cow diets in the form of sodium bicarbonate. The benefits of sodium bicarbonate addition are well documented but the mechanism of its action has not been defined. In experiment two, addition of dietary sodium increased total tract neutral detergent fiber digestibility probably by an expansion of ruminal contents and slowing of passage of digesta from the rumen. These effects are likely only a component of the mechanism of sodium bicarbonate action in lactating dairy cows. In this experiment, the addition of dietary sodium bicarbonate did not affect ruminal pH or alter the site of starch digestion. Sodium is a strong ion and strong ions are one of the determinants of the pH of a solution. In experiment three, we hypothesized that strong ion concentrations in the ruminal solution would be related to ruminal pH. Ruminal pH was correlated positively with ruminal sodium concentration, the sum of ruminal sodium and potassium, and ruminal strong ion difference, and was correlated negatively with total volatile fatty acid concentration, ruminal ammonium, and the sum of ruminal ammonium plus potassium. Also, ruminal sodium concentration was negatively related to the sum of ruminal potassium plus ammonium concentrations. Therefore, the total concentration of cations is controlled, balancing ruminal acidity and limiting ruminal osmolality. A uniform, alkalizing strong ion difference was maintained in the ruminal solution across animals and dietary treatments and this plus the charge balance in the rumen are likely regulated by modifying sodium flux across the ruminal epithelium. Sodium, as well as bicarbonate, are likely key in the whole body regulation of the volatile fatty acid load. These experiments suggest that lactating dairy cows actively regulate the ruminal environment especially sodium in the ruminal solution.

ISBN: 9780542908248Subjects--Topical Terms:

1017857
Agriculture, Animal Culture and Nutrition.

Regulation of the ruminal environment by lactating dairy cows.
LDR:03597nam 2200265 a 45 001 947772
005 20110524
008 110524s2006 ||||||||||||||||| ||eng d
020 $a 9780542908248
035 $a (UMI)AAI3236376
035 $a AAI3236376
040 $a UMI $c UMI
100 1 $a Mooney, Charles Steven. $3 1271245
245 1 0 $a Regulation of the ruminal environment by lactating dairy cows.
300 $a 288 p.
500 $a Adviser: Michael S. Allen.
500 $a Source: Dissertation Abstracts International, Volume: 67-10, Section: B, page: 5477.
502 $a Thesis (Ph.D.)--Michigan State University, 2006.
520 $a The ruminal environment must be regulated for the health and productivity of ruminants. Sodium is the most abundant cation in the ruminal solution and is the most likely candidate as the regulated ion. Three experiments were conducted to evaluate the role of strong ions in the ruminal environment. If sodium compounds are infused into the ruminal solution, rumination time is reduced markedly, however, these infusions may generate ruminal conditions that are not representative of normal physiological or nutritional conditions. In the first experiment, we hypothesized that additional dietary sodium at normal concentrations would reduce rumination time of dairy cows. Additional dietary sodium decreased rumination time as did additional dietary potassium indicating that the general decrease in rumination was caused by a tonic increase in ruminal osmolality. Sodium is often added to lactating dairy cow diets in the form of sodium bicarbonate. The benefits of sodium bicarbonate addition are well documented but the mechanism of its action has not been defined. In experiment two, addition of dietary sodium increased total tract neutral detergent fiber digestibility probably by an expansion of ruminal contents and slowing of passage of digesta from the rumen. These effects are likely only a component of the mechanism of sodium bicarbonate action in lactating dairy cows. In this experiment, the addition of dietary sodium bicarbonate did not affect ruminal pH or alter the site of starch digestion. Sodium is a strong ion and strong ions are one of the determinants of the pH of a solution. In experiment three, we hypothesized that strong ion concentrations in the ruminal solution would be related to ruminal pH. Ruminal pH was correlated positively with ruminal sodium concentration, the sum of ruminal sodium and potassium, and ruminal strong ion difference, and was correlated negatively with total volatile fatty acid concentration, ruminal ammonium, and the sum of ruminal ammonium plus potassium. Also, ruminal sodium concentration was negatively related to the sum of ruminal potassium plus ammonium concentrations. Therefore, the total concentration of cations is controlled, balancing ruminal acidity and limiting ruminal osmolality. A uniform, alkalizing strong ion difference was maintained in the ruminal solution across animals and dietary treatments and this plus the charge balance in the rumen are likely regulated by modifying sodium flux across the ruminal epithelium. Sodium, as well as bicarbonate, are likely key in the whole body regulation of the volatile fatty acid load. These experiments suggest that lactating dairy cows actively regulate the ruminal environment especially sodium in the ruminal solution.
590 $a School code: 0128.
650 4 $a Agriculture, Animal Culture and Nutrition. $3 1017857
690 $a 0475
710 2 $a Michigan State University. $3 676168
773 0 $t Dissertation Abstracts International $g 67-10B.
790 $a 0128
790 1 0 $a Allen, Michael S., $e advisor
791 $a Ph.D.
792 $a 2006
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3236376