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n. pl. ab·o·ma·sa (-sə)
The fourth division of the stomach in ruminant animals, such as cows, sheep, and deer, in which digestion takes place.

[New Latin abomāsum : Latin ab-, ab- + Latin omāsum, tripe; see omasum.]

ab′o·ma′sal (-səl) adj.


(ˌæbəˈmeɪsəm) or


n, pl -sa (-sə) or -si (-saɪ)
(Zoology) the fourth and last compartment of the stomach of ruminants, which receives and digests food from the psalterium and passes it on to the small intestine
[C18: New Latin, from ab-1 + omāsum bullock's tripe]


(ˌæb əˈmeɪ səm)

n., pl. -sa (-sə).
the fourth or true stomach of the cow and other ruminants, from which partially fermented and digested food is passed to the small intestine.
[1700–10; < New Latin; see ab-, omasum]


The fourth division of the stomach in ruminant animals, and the only one having glands that secrete acids and enzymes for digestion. It corresponds anatomically to the stomachs of other mammals. See more at ruminant.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.abomasum - the fourth compartment of the stomach of a ruminantabomasum - the fourth compartment of the stomach of a ruminant; the one where digestion takes place
ruminant - any of various cud-chewing hoofed mammals having a stomach divided into four (occasionally three) compartments
stomach, tum, tummy, breadbasket - an enlarged and muscular saclike organ of the alimentary canal; the principal organ of digestion
References in periodicals archive ?
In the deer's abomasum, or fourth stomach compartment, the gastropod releases infective larvae that migrate to the deer's spinal cord and brain, where they develop into mature egg-laying worms.
inserted into the abomasum through the rumen and held in place with a flexible rubber disk (18 cm i.
However it is advisable to separate fluid and milk feeds by 2-3 hours so that there is no adverse effect on milk clotting in the abomasum.
On days 5, 28, and 42, camels 1, 2, and 3, respectively, were euthanized, and samples were collected from nasal turbinates, lungs, trachea, larynx, pharynx, liver, spleen, kidney, bladder, urine, duodenum, jejunum, colon, rectum, abomasum, forestomachs, prescapular lymph node, retropharyngeal lymph node, tracheobronchial lymph node, mediastinal lymph node, mesenteric lymph node, medulla, and olfactory cortex.
Herds most at risk are those: With a 5% incidence of left dis-placed abomasum (fourth stomach).
3) Anaerobic digestion in the reticulorumen (1st and 2nd chamber of the stomach) and intestine of ruminants is interrupted by acidic hydrolysis in the abomasum (4th chamber or tree stomach) with a pH of around 2.
The manure pile is the fifth of the cows' four stomachs: after the men, reticulum, omasum, and abomasum, after the long and narrow passage through the intestine, after the deposition around the stall comes the final, longest act which takes place once again in the open.
Low DMI and deficiency in nutrient supply, specially protein and amino acids, lead to immunosuppression [34] and incidence of metabolic disorders consisted of rapid loss of BCS, ketosis, fatty liver and displaced abomasum [14,13,12].
The contents and gross appearance of the forestomachs and abomasum were unremarkable.
ABOMASUM The fourth stomach is a true stomach, and it works basically the same way your stomach does.
Once ingested, parasite larvae quickly find their way into the host's abomasum, or true stomach.
Microbial organic matter (MOM) and N (MN) leaving the abomasum was calculated using purines as a microbial marker (Zinn and Owens, 1986).