Effects of Dietary Cation -Anion Difference on Performance, Acid-Base Status, and Nitrogen and Macromineral Metabolism of Lactating Dairy Cows

In the second experiment, 16 Holstein and 8 Jersey multiparous cows were used immediately after calving to compare two DCAD4 (22 and 47 meq/100 g of DM) in a completely randomized design. An additional 2.3 kg of alfalfa hay was fed during the first 5 days postpartum, and then milk, blood, and urine samples were collected weekly for 6 weeks. Repeated-measures, with an extra between-cow effect, mixed model analysis indicated that DCAD 4 did not affect DM intake, milk production, milk composition, and jugular venous pH and HCO3- concentration. Elevated concentration of plasma branched chain AA and ratio of essential AA to total AA in cows with DCAD4 of 47 versus 22 meq/100 g of DM indicated N metabolism in the rumen was affected, probably a result of more microbial protein flowing to the small intestine. Higher net acid excretion in cows with DCAD4 of 22 versus 47 meq/100 g of DM suggested that net acid excretion was a much more sensitive indicator of acid load than blood acid-base parameters in cows postpartum.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Animal Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Hu, Wenping

Contributors dc:contributor

• Murphy, Michael R.

• Agriculture, Animal Culture and Nutrition

Language dc:language

eng

Identifier

(MiAaPQ)AAI3199024

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/83582