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ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Cell Wall Biology and Utilization Research » Research » Publications at this Location » Publication #350751
Research Project: Investigating Microbial, Digestive, and Animal Factors to Increase Dairy Cow Performance and Nutrient Use Efficiency

Location: Cell Wall Biology and Utilization Research

Title: Physiological effects of low rumen pH in calves before, during and after weaning

Author
item GELSINGER, SONIA - University Of Wisconsin
item Zanton, Geoffrey

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/8/2018
Publication Date: 6/11/2018
Citation: Gelsinger, S.L., Zanton, G.I. 2018. Physiological effects of low rumen pH in calves before, during and after weaning. Journal of Dairy Science. 101(Suppl. 2): 335.

Interpretive Summary:

Technical Abstract: The objective of this study was to determine the effects of low rumen pH in dairy calves. Starter diets were formulated to induce (A) or blunt (B) rumen acidosis in young dairy calves. Diet A was a complete pellet (42% starch, 13% NDF) and B was texturized (31% starch, 22% NDF). Ten (n=5/diet) Holstein bull calves were assigned to treatments at birth, cannulated at wk 3, and received milk replacer and a starter diet through wk 7, then starter only through wk 16. Rumen contents were sampled and pH recorded -8, -4, 0, 2, 4, 8, 12, and 24 h relative to starter feeding during wk 6, 8, 10, 12, 14, and 16 of age. Cobalt-EDTA was used to estimate liquid passage rate and rumen volume. Blood was drawn once every other wk to determine complete blood cell count, pH, hematocrit, hemoglobin concentration, and partial pressures of CO2 and O2. Calves were weighed weekly; starter intake was recorded daily. Calves were slaughtered and rumen tissue collected at wk 17. Formalin-fixed ruminal tissues were given a lesion score (0=healthy tissue, 5=severe degradation and inflammation). Statistical analyses were conducted in SAS with P<0.05 considered significant. Mean (min, max) rumen pH was lower for A than B calves: 5.4 (3.3, 7.2) and 5.6 (3.5, 6.8). Lowest mean pH values, 5.0 and 5.5 for A and B diets, were observed in wk 8. Starter consumption and body weight were lower in A calves beginning at 3 and 5 wk, respectively. Carcass weights were 68.1 and 82.2±1.8 kg for A and B calves. Rumen liquid volume tended to be greater in B calves (P = 0.08) and increased with age. Liquid passage rate was similar between treatments. Blood hemoglobin concentration and hematocrit were reduced in A calves. Blood pH decreased linearly with wk of age. No clear trends were observed for other blood parameters. Mean rumen lesion scores of rumen tissue were 3.7 and 2.3±0.2 in A and B calves. Growth and physiological responses were negatively affected in calves receiving A. Additionally, these calves responded similarly to mature cattle experiencing rumen acidosis, more research is warranted on the short- and long-term implications of this observation.