JDS
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J. Dairy Sci. 2008. 91:1959-1968. doi:10.3168/jds.2007-0882
© 2008 American Dairy Science Association ®
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Google Scholar
Right arrow Articles by Penner, G. B.
Right arrow Articles by Oba, M.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Penner, G. B.
Right arrow Articles by Oba, M.

Timothy Hay with a Low Dietary Cation-Anion Difference Improves Calcium Homeostasis in Periparturient Holstein Cows

G. B. Penner*, G. F. Tremblay{dagger}, T. Dow{ddagger} and M. Oba*,1

* Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
{dagger} Agriculture and Agri-Food Canada, Soils and Crops Research and Development Centre, Québec, Québec, G1V 2J3, Canada
{ddagger} Alberta Agriculture and Food, Lethbridge, Alberta, T1J 4V6, Canada

1 Corresponding author: masahito.oba{at}afhe.ualberta.ca

The current study was undertaken to evaluate the effects of feeding timothy (Phleum pratense L.) hay differing in dietary cation-anion difference (DCAD) on the capability of cows to maintain calcium homeostasis around parturition. We hypothesized that feeding low-DCAD timothy hay during the prepartum period would induce a mild metabolic acidosis prepartum and improve calcium homeostasis postpartum with no effect on dry matter intake. Forty-one dry pregnant Holstein cows entering their second lactation or greater were used in a randomized complete block design. Timothy hay was obtained from an established timothy stand under a pivot irrigation system. Low-DCAD timothy hay was produced by fertilizing the area between the second and third pivot towers at a rate of 224 kg of CaCl2/ha, and control timothy hay (high DCAD) was grown on the area between the fourth and fifth pivot towers of the same field. The chloride concentration was 1.07 and 0.15% on a dry matter (DM) basis, and the DCAD was 1.2 and 21.6 mEq/100 g of DM for the low- and high-DCAD timothy hay, respectively. Experimental diets, containing timothy hay at 63% of dietary DM, were fed ad libitum starting 30 d before the expected calving date. The DCAD values were 1.6 vs. 14.5 mEq/100 g of DM for the low- and high-DCAD timothy-based diets, respectively. At the beginning of the study, urine pH and blood bicarbonate concentration averaged 8.22 ± 0.06 and 28.5 ± 0.3 mM, respectively. The low-DCAD timothy diet decreased urine pH compared with the high-DCAD timothy diet on d 21 (7.75 vs. 8.31), d 14 (7.69 vs. 8.22), and d 7 (7.50 vs. 8.19) before calving, and it also decreased the prepartum blood bicarbonate concentration by 2 mM. In addition, cows fed the low-DCAD timothy diet had greater blood ionized calcium concentration prepartum (1.22 vs. 1.19 mM), greater blood ionized calcium concentration at 0 and 8 h after calving, and similar prepartum dry matter intake. These results indicate that timothy hay differing in DCAD affects the acid-base balance of periparturient dairy cows, and that low-DCAD timothy hay improves calcium homeostasis postpartum with no negative effect on dry matter intake.

Key Words: dairy cow • dietary cation-anion difference • calcium homeostasis • hypocalcemia






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2008 by the American Dairy Science Association ®.