Effects of forage feeding level on ruminal pH and metabolic adaptation of the rumen epithelium in pre-weaned Jersey calves.

The objective of this study was to determine the effect of limiting forage provision in pre-weaned calves on ruminal pH and short chain fatty acid (SCFA) transport capacity during the pre-weaning period. Twelve Jersey bull calves (age = 1.9 ± 0.

Effects of weaning on regulators of volatile fatty acid absorption and intracellular pH in Holstein calves.

This study examined the effects of changes in rumen fermentation during the weaning transition on abundance of transporters involved in volatile fatty acid (VFA) absorption or intracellular pH homeostasis. Holstein bull calves (n = 27) were assigned to 1 of 3 treatment groups in a randomized, complete block design: 2 preweaning groups [animals fed milk only (PRE-M) or milk, calf starter, and hay (PRE-S)] and 1 postweaning group (animals fed milk, starter, and hay with a 2-wk weaning transition; POST-S). Calves were euthanized at 42 d of age (PRE-M and PRE-S) or at 63 d of age (POST-S), and rumen epithelium and rumen fluid samples were collected.

Are constructs of the transtheoretical model for physical activity measured equivalently between sexes, age groups, and ethnicities?

Background/purpose: Identifying mediators of physical activity change requires measurement instruments that are reliable, valid, and generalizable to multiple populations. Despite continued application of the transtheoretical model (TTM) to the study of physical activity, the structural components of the TTM measurement instruments have been understudied in diverse populations.

Methods: A multiethnic sample (N = 700, M (age) = 47, 63% women, 38% Caucasian) of participants living in Hawaii completed TTM measures.