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(vertebrate zoology)
The final chamber of the complex stomach of ruminants; has a glandular wall and corresponds to a true stomach.



the fourth and last part of the multicompartmental stomach of ruminants, corresponding to the simple uncompartmental stomach of most mammals. The abomasum is connected to the omasum (third stomach) and the duodenum. The mucous membrane of the abomasum is covered by prismatic epithelium and contains fundic, pyloric, and cardiac glands. It forms 13 or 14 long folds, which enlarge its surface. In young animals the mucous membrane of the abomasum produces rennin. The muscular membrane of the abomasum consists of external longitudinal and internal circular layers. Food is digested in the abomasum by gastric juice.

References in periodicals archive ?
05) when starch was infused into rumen or abomasum at the concentration of 800 g/d (Table 5), which may be due to a lower starch infusion level and an experimental period which lasted from early to mid-lactating period.
reported that critical threshold of [beta]HBA for metabolic disorders such as displaced abomasums, clinical ketosis, metritis or retained fetal membranes are 0.
If farmers get the nutrition right to prevent displaced abomasums they will also increase their milk production as cows with this condition are just the tip of an iceberg,' he suggests.
Displaced abomasums are becoming par for the course in modern high-yielding Holsteins.
Larger particles of food that pass through the reticulo-omasal orifice are retained between the omasum's folds, with fluid components being transported comparatively rapidly to the abomasum.
Microbial organic matter (MOM) and microbial nitrogen (MN) leaving the abomasum were calculated using purines as a microbial marker (Zinn and Owens, 1986).
8), but soluble and released at the more extreme pH conditions found in the abomasum (pH 2.
In addition, numerous studies have recently demonstrated that feeding cattle diets rich in highly degradable carbohydrates results in disorders such as acidosis, fatty liver, laminitis, liver abscesses, displaced abomasum, and bloat (Nocek, 1997; Ametaj et al.
Once the contents had been removed, the weight of rumen, reticulum, omasum, abomasum, large and small intestines, liver, heart, spleen, lungs, and trachea was measured.
The digestive tract (esophagus, rumen, reticulum, omasum, abomasum, and small and large intestines) content was removed before the digestive tract was flushed with tap water, the excess water was then stripped manually, and weighed again.