Tolga AkayRuminant Nutrition

24 Hours in the Rumen

One day in the rumen on a single timeline. Choose a feeding scenario and press play to follow fermentation, rumination and the pH tendency hour by hour.

Educational simulationThis visualization demonstrates expected directional relationships and is not a validated animal-level prediction model.

Feeding scenarios

Balanced TMR: Moderate starch, adequate effective fibre, TMR delivered twice and pushed up regularly.
High starch: Fast-fermenting, finely processed grain with limited effective fibre.
High forage: Forage-based diet: slower fermentation and more rumination.
Irregular feeding: Late and uneven feed delivery: cows wait, then eat large meals.

A typical sequence after a meal

Feed delivery / meal
Fermentation activity increases
pH tends to decline
Post-feeding fermentation remains active
Rumination contributes to salivary buffering
pH tends to recover as acids are absorbed and buffered
Resting and rumination period

Timing and size of the responses are illustrative. Real responses depend on the diet, feeding behaviour, intake, particle size, fermentability, cow variation and management.

Methodology & references

The simulation combines the inputs into two relative scores, “acid load” (starch × fermentability, intake, low forage NDF) and “buffering” (peNDF, forage NDF, buffer, live yeast), and applies a meal-response curve for each feeding. Directions follow the reviewed literature; the size of the effects is illustrative and is not a validated prediction for any cow or herd. Real rumen pH can only be known by measurement (e.g. boluses or rumenocentesis).

Plaizier, J.C., Krause, D.O., Gozho, G.N., McBride, B.W. (2008). Subacute ruminal acidosis in dairy cows: the physiological causes, incidence and consequences. The Veterinary Journal 176: 21–31.
Krause, K.M., Oetzel, G.R. (2006). Understanding and preventing subacute ruminal acidosis in dairy herds: a review. Animal Feed Science and Technology 126: 215–236.
Allen, M.S. (1997). Relationship between fermentation acid production in the rumen and the requirement for physically effective fiber. Journal of Dairy Science 80: 1447–1462.
Bauman, D.E., Griinari, J.M. (2003). Nutritional regulation of milk fat synthesis. Annual Review of Nutrition 23: 203–227.