Zootechny

The General aspects about Farm animals

Zootechny is the art of breeding animals. It studies and manages whole the main aspects of Breeding technics and of the current laws. This art is based on whole of applications and fondation theories of Biology that they will be able to applicato to the breeding. Fenopipe , Genotipe of animals are considered and at same time tha clime , the temperature, the light, the breeding condition, the wealth constitution of animals and feeds.

General speaking, the Zootechny manages the fondation of Biology to applicate to own species of animal, this aim to lead to more and more better ways of breedind and as result two things could be abtained, first of all the wealth of animal and seondly a good quality product will be able to delivered to the constumers, in fact a wealthy animal will give us a high quality meat.

Severals arts are connected with Zootechy itself because severals species and breeding traditions occur, for instance: Anatomy, Phisiopatology, Etology.

The aim of this section of Food and Surrondings is to focus on whole the aspect of Breeding of the most important specie used to meal: Bovine, Sheep, Pigs, chikens and Game too.






 The Abomasum

The abomasum, also known as the maw, rennet-bag,  or reed tripe,  is the fourth and final stomach compartment in ruminants. It secretes rennet, which is used in cheese creation.

The word abomasum is from New Latin and it was first used in English in 1706. It comes from Latin ab- + omasum "intestine of an ox," and it is possibly from the Gaulish language.

The abomasum's normal anatomical location is along ventral midline. It is a secretory stomach similar in anatomy and function as the monogastric stomach. It serves primarily in the acid hydrolysis of microbial and dietary protein, preparing these protein sources for further digestion and absorption in the small intestine.

Dairy cattle on high production diets are susceptible to a number of pathologies, most commonly after calving. A gas-filled abomasum can move into an abnormal location, resulting in left-displaced abomasum (LDA) or right-displaced abomasum (RDA). If the abomasum displaces to the right, it is at risk of torsion and becoming a right torsioned abomasum (RTA). A displaced abomasum will cause cows to present all or some of the following signs: loss of appetite, decrease rumen contractions, decrease cud chewing, and drop in milk production.

While an LDA and RDA are not immediately life-threatening, veterinary care is required for surgical correction. Abomasitis is a relatively rare, but serious, disease of the abomasum whose causes are currently unknown.
The abomasum is used to make the lampredotto, a typical dish of Florence. It is also fried and eaten with onions as part of the Korean dish Makchang gui. Another dish made with the abomasum is Turkish Şırdan.
The abomasum is the fourth chamber in the ruminant. It functions similarly to the carnivore stomach as it is glandular and digests food chemically, rather than mechanically or by fermentation like the other 3 chambers of the ruminant stomach.

Structure and fuction

The abomasum differs in its position within the abdomen, depending on fullness of the other chambers of the stomach, intrinsic abomasonal activity, contractions of the rumen and reticulum (to which it is attached) and by age and pregnancy status.
Displacement of the abomasum to the left or to the right is a common disorder affecting dairy cows due to high concentrate feed.

The abomasum lies upon the abdominal floor. The cranial part is split into the pylorus and body. There is also a caudal part. It is covered by the lesser omentum. It has 15-20 folds inside. The torus is at the pyloric exit. The outflow is fairly constant. There is motility at the pylorus (peristalsis) and some control at the pyloric sphincter. The abomasum is large in newborn animals. The proximal ends of the abomasal folds form a plug preventing reflux into the omasum. It has thin walls and a serosa covering.

The function of the abomasum is the chemical breakdown of food. It secretes hydrochloric acid and pepsinogen. It has some intrinsic motility. Impaired motility can cause distension. The movements are slow, contractions occur first in the proximal part and are more forceful at the pyloric part.
The vasculature of the abomasum includes the cranial mesenteric artery, the celiac artery and the left gastric and left gastroepiploic arteries.
The innervation of the abomasum includes the dorsal vagus nerve (CN X) and the ventral vagus nerve (CN X)

Single lymph nodules are present at the junction between the epithelium and the lamina propria. Numerous small lymph nodes are scattered in the abomasal curvatures. The lymph drains to larger atrial nodes between the cardia and omasum, then to the hepatic lymph nodes.

 CN X :  Vagus nerve (X)

The vagus nerve is part of the group of cranial nerves responsible for innervation of structures derived from the branchial arches. It is also part of a group together with the glossopharyngeal and accessory nerves that passes through the jugular foramen which is termed the vagus group. The vagus nerve innervates structures related to the fourth branchial arch. The vagus nerve has cell bodies that are referred to as nucleus ambiguus.

The vagus nerve is composed of many different types of nerve fibre including general somatic efferent fibres supplying motor function to the muscles of the larynx, pharynx, palate and oesophagus; general visceral afferent fibres to the base of the tongue, pharynx and larynx; general visceral efferent fibres for parasympathetic supply of the thoracic and abdominal viscera; special visceral afferent fibres supplying taste to regions of the epiglottis and palate and finally general somatic afferent fibres to the external ear and the dura mater. The vagus nerve also supplies general somatic afferent fibres and special visceral afferent fibres to the root of the tongue.

There are many functional components of the vagus nerve including the heart, larynx, pharynx and many other viscera. On clinical examination any changes related to gag reflexes, blood pressure or heart rate, changes in 'voice' or inspiratory dyspnoea may indicate a problem with the vagus nerve.











Histology


The abomasum has a simple columnar epithelium. There are 3 layers of tunica muscularis - inner oblique, middle circular and outer longitudinal. The lamina muscularis is thicker and has 3 separate layers.

Gastric glands are present in the lamina propria of the mucosal layer in the pyloric region (lighter part). The abomasum is heavily coated by mucous for protection. The submucosa contains loose connective tissue, many blood vessels and unilocular adipocytes. The coiled glands in the lamina propria open into deep gastric pits. The inner mucosa is pink. Rugae are present in the pyloric region and a torus (large swelling) is present at the pyloric passage to narrow the lumen. The dark mucosa of the fundus and body contains peptic glands.

Normal Abomasum