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The rumen ( Latin pantex , from French panse "belly"; anatomically rumen ) is a hollow organ in ruminants ( ruminantia ) and the largest of the three fore-stomachs . It is a large fermentation chamber , which is upstream of the actual glandular stomach (known as the abomasum in ruminants ). In the rumen, the cellulose is broken down by microorganisms (“rumen flora”) and the resulting compounds are absorbed . Together with the reticulum ( reticulum he cares) for the initiation of rejection (regurgitation in the oral cavity ) coarse feed components to the rumination and the further transport of comminuted and pre-digested food components into the omasum . The rumen and reticulum are therefore functionally combined to form the ruminoreticulum and arise from a common system in the embryo .

Stomach of a calf: m - end of the esophagus, v - rumen , n - reticulum, b - leaf stomach  , l - abomasum, t - beginning of the small intestine


Size and location

In adult animals, the rumen is the largest of the three fore- stomachs. It takes up the entire left half of the abdominal cavity , in the rear area it sometimes even takes up part of the right half of the abdomen. Only the reticulate stomach lies on the left side of the diaphragm in front of the rumen; in ruminants , the liver is completely displaced to the right side of the abdomen by these two fore-stomachs. The rumen lies with its left wall surface ( Facies parietalis ) directly on the inside of the left abdominal wall and extends from the 8th  rib to the pelvic entrance . Its visceral surface ( facies visceralis ) borders on the leaf and abomasum in front, and further back on the intestinal convolute . The rumen of the adult domestic cattle has a capacity of up to 100 liters , of the domestic sheep of around 10 liters and thus takes up around 75 to 80% of the total stomach volume.


Stomach of a sheep from the left, 1–13 rumen. 1 centrifugal stomach, 2 dorsal rumen sac, 3 ventral rumen sac, 4 ruminous recess, 5 caudodorsal blind sac, 6 caudoventral blind sac, 7 cranial sulcus, 8 left longitudinal furrow, 9 dorsal coronary sulcus, 10 ventral coronary sulcus, 11 caudal sulcus, 12 accessorial sulcus 13 rumen island, 14 rumen reticulum furrow, 15  reticulate stomach , 16  abomasum , 17  esophagus , 18  spleen .

The rumen is divided into several sub-chambers by externally visible furrows. In the area of ​​these furrows, there are raised bulges on the inside, the rumen pillars ( pilae ).

The left and right longitudinal furrows ( sulcus longitudinalis sinister and dexter ) or the corresponding pillars inside ( pila longitudinalis sinister and dexter ) divide the rumen into its two main divisions, the back ( saccus dorsalis ) and the abdominal rumen sac ( saccus ventralis ). The front part of the rumen sac on the back protrudes over the belly side. This part is called the rumen atrium ( atrium ruminis ) or "sling stomach " . The spleen has grown together with it. The front part of the belly-side rumen sac is called the ruminous recess ("rumen sac"). Between these two front sections lie the sulcus or pila cranialis . From the left and right longitudinal furrows there is an additional furrow that separates and runs further up ( sulcus accessorius dexter and sinister ) or corresponding pillars ( pila accessoria dextra and sinistra ) that delimit the rumen island ( insula ruminis ).

To the rear, the two rumen sacs are separated from the two rumen blind sacs ( Sacci caeci ) by the coronary furrow ( sulcus coronarius ventralis or sulcus coronarius dorsalis ) on the back or abdomen, respectively , inside by the pila coronaria ventralis or dorsalis . Between the backward and upward directed saccus caecus caudodorsalis and the backward and downward directed saccus caecus caudoventralis lie the sulcus or pila caudalis . The deer have three blind sacs.

From the adjacent forward reticulum ( reticulum ) of the centrifugal stomach through the rumen-reticular furrow ( sulcus ruminoreticularis defined). Only for the ruminoreticular sulcus there is no corresponding pillar in the rumen. Instead, a ruminoreticular plica is found here. The esophagus opens from above in this border area between the two foregomies .

The rumen is only fused to the abdominal wall in a small area of ​​the anterior back rumen sac and is held in place by gravity, its contents and the other internal organs. The large network ( omentum majus ) is attached to the longitudinal furrows . Its deep wall ( paries profundus ) runs along the right longitudinal furrow, encloses the rumen and continues along the left longitudinal furrow as a superficial wall ( paries superficialis ). The paries superficialis again runs ventrally around the rumen and extends to the right upper trunk wall as well as to the leaf and abomasum.

Vessels and nerves

The blood supply is provided by the right and left rumen arteries ( arteria ruminalis dextra and sinistra ), which arise from the splenic artery ( arteria lienalis ). The right rumen artery is the larger of the two rumen arteries. It moves backwards in the right longitudinal furrow, turns in the caudal sulcus to the side of the abdominal wall of the rumen and thus also supplies the rear part of the left rumen wall. The left rumen artery also runs over the cranial sulcus to the side of the abdominal wall. The corresponding veins flow into the portal vein ( Vena portae ) and thus ensure that the nutrients absorbed in the rumen reach the liver directly .

The lymph vessels lead to several groups of lymph nodes in the gastric lymph nodes ( Lymphonodi gastrici ). The right rumen lymph nodes ( Lymphonodi ruminales dextri ) lie along the right, the left ( Lymphonodi ruminales sinistri ) in the left rumen longitudinal furrow. In addition, the anterior rumen lymph nodes ( Lymphonodi ruminales craniales ) in the sulcus cranialis and the rumen- abomasal lymph nodes ( Lymphonodi ruminoabomasiales ) on the anterior underside of the rumen in the area of ​​the contact surface with the abomasum are included in the lymphatic drainage.

The nervous control ( innervation ) of the rumen is carried out by the vegetative (autonomous) nervous system . The parasympathetic vagus nerve (Xth  cranial nerve ) pulls in the form of an upper and lower trunk ( truncus vagalis dorsalis and ventralis ) together with the esophagus on the rumen. The main supply is provided by the upper trunk, the lower one only participates in the innervation of the gizzard. The efferent (towards the rumen) nerve fibers of the vagus trunks stimulate the motor function of the rumen, the afferent ( towards the rumen) conduct impulses from mechano and chemoreceptors into the elongated medulla ( medulla oblongata ). The reflex center, which controls the rumen movements without the involvement of the conscious mind, is also located in this part of the brain stem . The sympathetic nerve fibers reach the rumen with the blood vessels via the plexus plexus ( plexus celiacus ). Their efferents have an inhibiting effect on the movements of the forestomach, the afferents conduct pain stimuli . The contraction of the smooth muscles of the rumen is mediated via the ganglion cells of the intestinal nervous system , but ordered movements (see rumen motor skills) are not possible without the influence of the vagus. The nerve cells of the intestinal nervous system are located between the two muscle layers of the rumen in the form of the myenteric plexus (Auerbach plexus). The submucosal plexus (Meissner's plexus), in contrast to the other sections of the gastrointestinal canal , is not formed on the foregometals.


Histological preparation of a sheep rumen. 1 rumen villi, 2 epithelium, 3 mucous membrane, 4 connecting layer, 5 muscle layer, 6 peritoneum
Mucous membrane of the rumen of a sheep with rumen villi; in the middle a rumen pillar

Like all internal hollow organs, the rumen consists of an internal mucous membrane , a muscle layer of smooth muscles and the external peritoneum . In the area of ​​the spleen resting on the rumen, the upper front part of the rumen grows together with the abdominal wall, so that a small area is without a peritoneum coating.

Rumen villi

In contrast to the first compartment of the camel's fore-stomachs , the mucous membrane forms rumen villi ( papillae ruminis ) in ruminants to increase the surface area, in cattle by about a factor of 7. The size, shape and distribution of these villi varies according to the diet and the current situation available food. The villi develop in the embryo and are thread-shaped with a round to oval cross-section, in adult animals they are mostly tongue-shaped, but vary according to the food available (see below). The approximately 300,000 larger villi ("main villi") in large ruminants are up to 13 mm long in cattle and up to 25 mm long in giraffes . In the so-called grass and roughage eaters (e.g. cattle , sheep , mouflon ), the rumen pillars are mostly villi-free and the rumen roof and floor have only a few, short villi. In the case of the “ selectors ”, i.e. those ruminants who consume plants that are poor in crude fiber and easily digestible (e.g. deer , elk , giraffe), the villi are more evenly distributed and mostly also formed on the pillars. In the case of the "intermediate type", ie those animals that take up plants from both categories (e.g. red deer , goats , impala ), the villi in the area of ​​the pillars are only short.

Depending on the food supply and thus the composition of the fatty acids produced during fermentation, changes in the villi occur. So under poor nutritional conditions (winter, dry season ) the villi decrease in number, length and thickness ("hunger villi") and then resemble the thread-like villi of the fetus . This process is reversible, the adjustment process takes about two to three weeks. The changes are most pronounced in the intermediate type. The adaptation processes not only affect the villi, but also the intrinsic layer of the mucous membrane and the architecture of the blood vessels.

Mucous membrane

The mucous membrane of the rumen is free of glands and has a multilayered keratinized squamous epithelium .

The rumen epithelium is modified with regard to the resorption function of the rumen and is subject to cyclical changes caused by resorption processes. The epithelium is subdivided into five layers, which with optimal nutritional conditions usually consist of only one cell layer. In addition to the actual epithelial cells, white blood cells and Langerhans cells that migrate through the epithelium also occur, which serve the immune defense .

Light microscopic picture of a rumen villus. 1 balloon cell, 2 granule cells, 3 parabasal cells, 4 basal cells, 5 self-layer, 6 papillary bodies, 7 villi central artery
The stratum basale of the epithelium lies against the basement membrane . The highly prismatic basal cells are anchored to the basement membrane via hemidesmosomes and have a relatively large nucleus . The gaps between the basal cells are relatively wide, the cells are connected to one another by desmosomes sitting on long cytoplasmic processes .
The deep prickly cell layer ( Stratum spinosum profundum ) of the epithelium consists of the polygonal parabasal cells . They also have wide intercellular spaces bridged by cell processes. The cell processes sometimes also extend to the basement membrane. The cell contacts behave like the basal cells.
The superficial spiny cell layer ( stratum spinosum superficiale ) is composed of the flattened intermediate cells arranged parallel to the surface . Their appendages are particularly rich in tonofilaments and adhesive plates for the formation of desmosomes. The intermediate cells contain many lysosomes .
The granule cell layer ( stratum granulosum ) of the epithelium consists of two types of granule cells . The type A granule cells are still similar to the intermediate cells, but only have short cell processes. They contain small nuclei and little keratohyalin - granules . The type B granule cells are larger and have already severely shrunken (pyknotic) cell nuclei. They do not form a cohesive layer of cells and contain clumps of keratohyalin. The fusion of the cell membranes results in the formation of tight junctions in the granular cells facing the interior .
The horny layer ( stratum corneum ) lying to the cavity of the rumen consists of horn cells. The type A horny cells are already flattened and filled with keratohyalin clods and cell nucleus remains. They are connected to one another via tight junctions. The type B horn cells with spongy loosened keratin arise from them . These cells can detach themselves from the epithelial association or develop further into type C horn cells ( balloon or source cells ). The latter are balloon-shaped due to further swelling, the cell organelles have almost disappeared and the corrugated cell membrane can finally tear. Balloon cells are usually missing in the villi-free regions and when there is poor food supply.

The intrinsic layer of the mucous membrane ( lamina propria mucosae ) forms a papillary . The own layer consists of collagenous and elastic connective tissue with some defense cells ( leukocytes , plasma cells , mast cells ). The fine blood vessels and nerve fibers lie in it. In the process, two villi marginal arteries and one or two central villi arteries extend from the vessels of the self-layer at the base of the rumen villi into the villi, from which arterioles extend parallel to the epithelium . These feed a dense network of capillaries directly under the epithelium. The draining venules are also located directly under the epithelium and have an endothelium with pores to facilitate the exchange of substances. The venules are partially expanded to form sinusoids . A mucous membrane muscle layer ( lamina muscularis mucosae ) is missing, but the connective tissue of the own layer is compressed into a lamina compacta , which also contains some smooth muscle cells. The intrinsic layer merges smoothly into the connecting layer ( tela submucosa ) with its vascular networks. Lymph follicles and glands are not formed in the mucous membrane of the rumen.

Muscle layer

Like the entire gastrointestinal tract, the muscle layer consists of an inner ring and an outer longitudinal muscle layer, but this arrangement has been modified. The longitudinal muscle layer of the remaining gastrointestinal canal only radiates into the back of the rumen and rumen blind sac; it corresponds to the external oblique fibers ( Fibrae obliquae externae ) of the single-cavity stomach. The sphincter layer, on the other hand, only extends to the gizzard and the stomach-side rumen sections. In addition to this muscle layer, there is a second muscle layer, which also forms the muscle loop at the entrance to the stomach and corresponds to the internal oblique fibers ( fibrae obliquae internae ) of the single-cavity stomach. It encompasses all rumen sections in a ring. With this additional layer, the muscular layer of the rumen also consists of two layers with different directions at all points.

Development history

While the separation of ungulates into pair and odd- toed ungulates took place in the early Eocene , the evolution of ruminants and thus of the rumen did not begin until the Oligocene and reached its peak in the Miocene . In the process, the ruminants and camels developed a multi-chambered stomach, which initially only served for short fermentation, similar to recent selectors (such as deer). Only with the development of the delay mechanisms in the forestomach system (reticulum-leaf stomach opening) could also hard-to-digest and crude fiber-rich forage plants be used.

In contrast to ruminants, the camel's stomach consists of three glandular compartments. Occasionally the first compartment of the camels is also referred to as "rumen", which should be avoided due to the morphological differences. Such rumen with a multilayered cornified squamous have also sloths , peccaries and whales (with the exception of beaked whales ). In monotremes and shed animals of the entire stomach is lined like that.

In the ruminant embryo , all gastric compartments arise from the spindle-shaped gastric anlage, as can also be found in other mammals. In ruminants, the gastric system only turns 90 ° to the left when the stomach is first turned . The rumen develops together with the reticulum (hood) in the area of ​​the great curvature ( curvatura major ) as a bulge facing left, front and top, the rumen hood system. All four stomach sections are already created in the 20 mm long bovine embryo. With the increase in size, the two blind sacs also grow out, which are initially directed upwards and forwards. With the regression of the urnal kidney, the rumen rotates over the back so that the blind sacs are shifted backwards and the rumen assumes its definitive position.

At birth, the rumen is still the largest gastric compartment with a volume share of 47%, closely followed by the abomasum (around 40%). During the suckling period in the first weeks of life, the abomasum grows larger than the rumen, as the breast milk is digested there and is conducted past the fore-stomachs via the hood reflex . Only with the uptake of structurally effective crude fiber does the rumen develop under the influence of mechanical and chemical stimuli ( fatty acids produced by fermentation ) into the clearly largest gastric department. This also leads to the transformation of the rumen villi as described above. The colonization of the rumen with microorganisms occurs in young animals mainly through contact with other animals, bacteria are also ingested with the food.


There is a stratification of the contents in the rumen. The liquid phase is in the lower section. Coarser plant components float on it in the middle section and a gas bubble forms at the top. The liquid phase with its solid suspended particles and microorganisms is called rumen juice .

Rumen flora and fauna

The totality of microorganisms in the rumen is referred to as the rumen flora and fauna . These are predominantly anaerobic (only viable in the absence of oxygen) bacteria , single-cell organisms (so-called "infusoria") and fungi . They make up about 20% of the volume of the rumen contents.

The bacteria break down carbohydrates ( cellulose , hemicellulose , pectins , xylans , sugar ) and proteins . In the rumen there are about 10 10 to 10 11 bacteria / ml, which mainly adhere to the surfaces of the food particles and the rumen epithelium. They belong to about 200 different species, including Ruminococcus spp., Lactobacillus spp., Clostridium spp. and Bacteroides spp. In addition to the breakdown processes, the bacteria are also involved in maintaining the rumen environment. The oxygen-consuming bacteria adhering to the epithelium maintain the anaerobic environment and the negative redox potential of −250 to −300 mV ensures that the carbohydrates are only broken down down to the short-chain fatty acids and not completely into carbon dioxide and water. The archaea in the rumen sap form methane from carbon dioxide and hydrogen and thus lower the partial pressure of hydrogen in the rumen, which prevents the excessive formation of ethanol and lactic acid . Methane cannot be used by ruminants and has to be emitted together with the carbon dioxide as "exhaust gas" via the trunk . The release of this hydrocarbon, however, reduces the efficiency of energy utilization.

The protozoa make up about half of the biomass of the rumen flora and are mainly composed of ciliates (10 5 to 10 8 / ml, mainly representatives of the Isotrichidae and Ophryoscolecidae ) and, to a lesser extent, flagellates (10 3 to 10 4 / ml) . Protozoa are involved in the breakdown of carbohydrates and proteins to a lesser extent (approx. 10%). They can absorb easily degradable carbohydrates and thus prevent their rapid degradation and thus rumen acidosis due to excessive amounts of organic acids. In addition, the protozoa can break down or bind harmful components of the food (toxic plant components and heavy metals). In addition, the protozoa ingest bacteria and thus regulate their population. However, the protozoa do not seem to be absolutely necessary for the forestomach activity, multiple studies even show that they are responsible for an inefficient use of nitrogen. The efficiency of nitrogen use can be increased by removing the protozoa from the rumen, known as defaunation. In addition, methane production can be reduced, since protozoa are used by methane producers as hosts.

So far, no reliable knowledge is available about the importance of the fungi occurring in the rumen ( Neocallimastigaceae ). They utilize soluble carbohydrates and proteins to a small extent and are also capable of producing long-chain fatty acids. Their occurrence is also considered not absolutely necessary.


The β-glycosidic bonds of structural carbohydrates are broken by the rumen flora, especially those of cellulose , which cannot be broken down by the digestive enzymes of mammals. The resulting grape sugar (glucose) serves as a substrate for the microorganisms; the products of their metabolism include short-chain carboxylic acids such as propionic acid , butyric acid and, above all, acetic acid . In order to grow, the microorganisms need fermentable carbohydrates as well as nitrogen , which is supplied by the protein contained in the feed, but also by non-protein nitrogen (NPN). Proteins are largely split into peptides , amino acids or ammonia by the microorganisms in the rumen and then serve them as a nitrogen source.

The ruminant therefore provides the microorganisms with the fermentation chamber and the substrate. The microorganisms provide the ruminant with:

  1. Energy : Volatile carboxylic acid derivatives are an essential product of microorganisms . A cow produces around 5 mol of short-chain fatty acids per kg of dry matter intake, a high-performance dairy cow alone produces around 45 mol of acetate per day. These are absorbed by the ruminant through the rumen wall.
  2. Proteins : The microorganisms themselves do not remain permanently in the rumen, but gradually leave it, while new ones arise through reproduction. In the small intestine, the microorganisms are then largely digested by the ruminant and thus provide the animal with proteins. Therefore, the microorganisms themselves are an important source of protein for ruminants and thus indirectly enable them to utilize inorganic nitrogen sources as well.
  3. Vitamins and a .: In addition to energy and protein, the microorganisms also provide the ruminant with various vitamins and the like. a .; for example, the microorganisms can synthesize cobalamin (vitamin B12) and many others.

Various mechanisms exist to maintain the environment required for microorganisms, for example the volatile fatty acids in the rumen have a pH-lowering effect. The physiological pH value of the rumen is 5.5 to 7. At lower pH values ​​( rumen acidosis ) the environment for the microorganisms becomes unfavorable. That will u. a. counteracted by chewing with swallowed saliva , as it contains buffering substances ( above all bicarbonate , HCO 3 and hydrogen phosphate, HPO 4 2− ). Depending on the feed intake of the ruminant (high-performance cows:> 25 kg dry matter), up to 270 liters of saliva can be formed per day.

Resorption processes

Resorption processes in the rumen (FS = fatty acids, FS - = dissociated FS, FS-D = fatty acid derivatives)

The rumen epithelium represents a barrier against passive resorption processes, it maintains chemical gradients between the rumen contents and blood and is therefore called "moderately dense epithelium". This barrier function prevents the blood from becoming too acidic . There are various cellular transport proteins for minerals ( sodium , chloride , potassium , magnesium , calcium ) for the extensive resorption processes that take place in the rumen . Magnesium absorption, in particular, plays a major role, as it takes place almost exclusively in the rumen of ruminants and a magnesium deficiency in cattle in spring is not uncommon ( pasture tetany ). Phosphate is presumably only absorbed passively and in small amounts via diffusion between the rumen epithelial cells (paracellular). Under normal conditions, water is only absorbed in small amounts due to osmotic gradients.

The short-chain fatty acids produced during fermentation are presumably absorbed passively via a material gradient , both dissociated and undissociated. A large part of these are chemically converted in the rumen epithelial cells ( butyric acid in ketone bodies , propionic acid in lactic acid ) before they are released into the blood. As a result, the gradient between the lumen and epithelial cell is maintained and the epithelial cell uses these substances to generate energy that is necessary for the active transport processes.

At physiological pH values , the ammonia produced during protein breakdown is mostly present as ammonium ions (NH 4 + ) and is mostly used by the rumen flora for protein synthesis and in part also absorbed into the epithelial cells via potassium channels. At high pH values ​​( rumen alkalosis ), more ammonia is produced, which, due to its lipid solubility, can easily enter the cells and has to be detoxified by the liver . Various manufacturers therefore offer feed with rumen-resistant protein . The amino acids and peptides produced during protein breakdown are not or only in traces absorbed in the rumen.

Urea can be released into the interior of the rumen via the saliva, blood and rumen epithelium and is thus available for microbial protein synthesis. In contrast to other mammals , where the urea has to be excreted in the urine , ruminants are able to recycle it, up to 90% when fed low-protein. This process is called the rumen-liver cycle ( rumino-hepatic cycle ). Part of the urea is released through the milk (→ milk urea ).

In addition to urea, potassium, H + , HCO 3 - and water can also be transported back into the rumen.

Rumen motor skills

A cycle of rumen motor skills. Double contraction of the hood (1) - contraction of the ejected stomach (2) - contraction of the back rumen sack (3) and blind sack (5) - contraction of the abdominal rumen sack (4) and blind sack (6)

The microbial breakdown, rumination and further transport are maintained by a complicated sequence of muscle contractions, the so-called rumen motor skills .

These contractions of the rumen muscles and the rumen pillars ensure that the contents are constantly mixed. A distinction is made between so-called A-cycles with involvement of the reticulum and B-cycles that take place in the rumen alone. These movements are controlled via the reflex center in the brain stem and are mediated afferently via the stretching and chemoreceptors of the rumen wall and chemoreceptors of the duodenum , and efferent via the vagus nerve. In the case of fever and pain, the rumen motor skills are inhibited.

When ruminating, a chunk coarse feed ingredients is lifted in front of the entrance to the stomach by the contraction of the network and spin stomach, by inhalation at elevated soft palate sucked and by an opposite wave of contraction (Anti peristalsis ) of the esophagus into the oral cavity conveyed back (rejiziert). Then the food is chopped up with the teeth and swallowed again in the rumen.

The already finely chopped and largely decomposed parts of the food, including the microorganisms, collect in the rumen sac on the stomach side due to their higher density. Through the contraction of this rumen part, they reach the reticulum, which transports them to the leaf stomach.

The fermentation gases that accumulate in the rumen sac on the back are released through a reflex mediated by the vagus nerve , the so-called trunk . The gas is transported by a contraction of the rumen sac on the back during a B-cycle to the esophageal opening, which opens reflexively, and from there it is directed towards the mouth via anti-peristalsis in the esophagus. Since the soft palate closes the path and the mouth is closed, the gas first reaches the lungs , where the carbon dioxide is partially absorbed, which triggers rapid breathing movements . A break occurs about twice a minute.


The examination of the vital rumen motor skills is part of every general clinical examination in ruminants. It can be felt through observation, listening or a fist pressed into the left hunger pit . In a healthy animal, two to three contraction cycles can be detected in two minutes. The most important functional examination is the removal of rumen juice via a rumen probe inserted through the mouth and its examination. Above all, the pH value and microscopically the rumen flora are assessed.


The rumen flora is in a delicate balance . If the pH value shifts to the acidic ( rumen acidosis ) or alkaline range ( rumen alkalosis ), severe damage to the rumen flora, the rumen epithelium and increased formation of unfavorable metabolic products occur (see the Function section ). The causes are mostly feeding errors such as high-energy feed (grain) with insufficient crude fiber content (acidosis) or low-energy and protein-rich feed (alkalosis). Feed changes lead to a species shift in the rumen flora and changes in the mucous membrane. Abrupt changes in feed (> 15% of the ration) can cause changes in the pH value and disturbance of the flora balance as well as cornification disorders of the epithelium ( hyperkeratosis , parakeratosis ). They must therefore be avoided and stretched to 10 to 20 days in order to allow the adjustment processes the necessary time. Withdrawal of feed for a few days (e.g. during transport) also leads to severe disorders of the rumen flora and the metabolism of the animal ( alkalosis , ketosis ). In the same way, calves must gradually increase their feeding of green fodder before weaning in order to stimulate the physiological development of the rumen and rumen flora. In case of failure of the hood trough reflex in calves milk enters the rumen and is fehlvergoren there, causing indigestion and diarrhea.

Feeding food rich in starch or protein can lead to foamy gas bubbles in the rumen. A rumen tympany (inflation) occurs because the gases can no longer be released through the trunk. Then the gas accumulation must be removed either with foam-breaking medication and a tube inserted into the rumen or, in emergencies, with a rumen stab with a trocar .

A disorder of the rumen motor skills can occur due to damage to the vagus nerve in the so-called Hoflund syndrome or a lack of structurally effective crude fiber. If the rumen motor functions fail (rumen atony ), both the microbial degradation processes and the gas release are severely disturbed, which quickly leads to a life-threatening condition.

An inflammation of the rumen mucosa ( Ruminitis ) occurs mainly in the rumen acidosis, and during recording chemical substances harmful or hot feed. It can also be caused by various bacteria ( Arcanobacterium pyogenes , Fusobacterium necrophorum ) with previous damage to the mucous membrane or it can occur as a side effect of some viral diseases ( foot and mouth disease , malignant catarrhal fever ).

In the case of foreign body disease, the foreign body usually bores through the reticulum, less often through the rumen. A flank incision is usually carried out here, the surface of the rumen wall is scanned and the foreign body is then removed from the reticulate stomach or rumen via a rumen incision. Magnets inserted in the rumen can prevent foreign body disease from metallic objects. When feeding heavily soiled forage, the rumen can silt up, which must be surgically removed if it is more severe.

In the event of severe damage to the rumen flora, e.g. B. can also be triggered by antibiotics or toxic substances, this must be restored by transferring rumen juice from another animal.

Man and rumen

As tripe is called rumen pieces for human consumption, which must first be subjected to an elaborate kitchen technical preparation.

Nutrient content per 100 g of green rumen
TS 28 g Approx 120 mg
Raw fat 5 g P 130 mg
vRP 19 g Mg 40 mg
ME 0.58 MJ K 100 mg
Crude fiber 1.1 g N / A 50 mg

Rumen as pet food

Rumen press in Seegrenzschlachthof (1929)

Pieces of rumen are also used as pet food, especially for dogs . They are found in some commercial dog foods and are also sold dried as rumen sticks. Rumen can also be used fresh (“green” rumen or cleaned) for the individual production of dog food. Due to its composition, rumen is not suitable as a complete feed .

Ecological damage

The gases produced in the rumen cannot be used without further ado. The roughly 200 liters of rumen gases (60% CO 2 , 40% methane) produced by a cow per day represent an environmental burden, especially in regions with a high density of cattle (see greenhouse effect ). However, the rumen is also a natural model for the production of biogas (methane) in technical systems . In 2005, researchers at Ohio State University succeeded in producing a microbial fuel cell using bacteria from the rumen flora .


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  • RR Hoffmann, B. Schnorr: The functional morphology of the ruminant stomach . Enke-Verlag, Stuttgart 1982, ISBN 3-432-88081-2 .
  • M. Kressin, B. Schnorr: Embryology of domestic animals. 5th edition. Enke-Verlag, Stuttgart 2006, ISBN 3-8304-1061-1 .
  • N. Rossow: Diseases of the forestomach and abomasum. In: N. Rossow (Hrsg.): Internal diseases of farm animals . Gustav Fischer Verlag, Jena 1984, pp. 224-259.
  • Franz-Viktor Salomon: stomach, ventriculus (gaster). In: Salomon u. a. (Ed.): Anatomy for veterinary medicine . 2nd ext. Edition. Enke-Verlag Stuttgart 2008, ISBN 978-3-8304-1075-1 , pp. 272-293.

Web links

Wiktionary: rumen  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. Optimization of the microbial conversion in the rumen through feeding . ( Memento of March 13, 2014 in the Internet Archive ) (PDF; 845 kB).
  2. a b Jörg R. Aschenbach: The acid-base balance in the rumen. In: Vet-MedReport. V10, 2009, p. 2.
  3. J. Kamphues et al. a. (Ed.): Supplements to lectures and exercises in animal nutrition. 9th edition. Schaper, Hannover, p. 250.
This article was added to the list of excellent articles on December 23, 2006 in this version .