| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
* Agriculture and Agri-Food Canada, Lethbridge, Alberta, Canada Agriculture and Agri-Food Canada, Research Centre, Lethbridge, Alberta T1J 4B1, Canada
Agroscope Liebefeld-Posieux, Research Station ALP, Posieux, Switzerland
2 Corresponding author: tdevries{at}kemptvillec.uoguelph.ca low ruminal pH. These results suggest that feed sorting is affected by whether cows are at risk of acidosis. Furthermore, cows experiencing severe acidosis preferentially sort their feed to attenuate the effects of this condition.
An experiment was conducted to determine whether the susceptibility of cows to ruminal acidosis influences feed sorting and whether feed sorting changes during a bout of ruminal acidosis. Eight ruminally cannulated cows were assigned to 1 of 2 acidosis risk levels: low risk (LR, mid-lactation cows fed a 60% forage diet) or high risk (HR, early lactation cows fed a 45% forage diet). As a result, diets were intentionally confounded with milk production to represent 2 different acidosis risk scenarios. Cows were exposed to an acidosis challenge in each of two 14-d periods. Each period consisted of 3 baseline days, a feed restriction day (restricting TMR to 50% of ad libitum intake), an acidosis challenge day (1-h meal of 4 kg of ground barley/wheat before allocating the TMR), and a recovery phase. Ruminal pH was measured continuously for the first 9 d of each period using an indwelling system. Feed and orts were sampled for 2 baseline days, on the challenge day, and 1 and 3 d after the challenge day for each cow and subjected to particle size analysis. The separator contained 3 screens (18, 9, and 1.18 mm) and a bottom pan to determine the proportion of long, medium, short, and fine particles, respectively. Sorting was calculated as the actual intake of each particle size fraction expressed as a percentage of the predicted intake of that fraction. All cows sorted against the longest and finest TMR particles and sorted for medium-length particles. Sorting was performed to a greater extent by the HR cows, and this sorting was related to low ruminal pH. Both HR and LR cows altered their sorting behavior in response to acidosis challenges. For the HR cows, severe acidosis was associated with increased sorting for the longer particles in the diet and against the shorter particles, likely to lessen the effects of the very
Key Words: acidosis • sorting • rumen pH
This article has been cited by other articles:
|
|
 |
|
  T. J. DeVries, K. A. Beauchemin, F. Dohme, and K. S. Schwartzkopf-Genswein Repeated ruminal acidosis challenges in lactating dairy cows at high and low risk for developing acidosis: Feeding, ruminating, and lying behavior J Dairy Sci, October 1, 2009; 92(10): 5067 - 5078. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. J. DeVries and M. A. G. von Keyserlingk Competition for feed affects the feeding behavior of growing dairy heifers J Dairy Sci, August 1, 2009; 92(8): 3922 - 3929. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. K. Miller-Cushon and T. J. DeVries Effect of dietary dry matter concentration on the sorting behavior of lactating dairy cows fed a total mixed ration J Dairy Sci, July 1, 2009; 92(7): 3292 - 3298. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. B. Penner and M. Oba Increasing dietary sugar concentration may improve dry matter intake, ruminal fermentation, and productivity of dairy cows in the postpartum phase of the transition period J Dairy Sci, July 1, 2009; 92(7): 3341 - 3353. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
