**5. Digestive system of the goat**

The organs present in this system are responsible to get the food, chemically and mechanically breaking it down into smaller pieces and then absorbing them so that it can be used to get energy and body growth and renewal of cells and tissues. Later, it has to remove the unabsorbed portion of the food. This system extends from mouth to anus, including other accessory gland and organs (**Figure 3**). The anal canal is a

short tube and is the terminal portion of the elementary canal. This is controlled by internal consists of smooth muscle and external anal sphincters consists of striated muscles [45].

## **6. Oral cavity**

The oral cavity plays an important role in procuring and mastication of food particles. The oral cavity includes tongue, lips, teeth gum, cheeks, palate (hard and soft), and the vestibular space. The tongue is the mobile muscular tissue covered dorso-ventrally by stratified squamous epithelium and has three parts: root, body, and apex. Within the oral cavity, the tongue is supported by the hyoid bone caudally, mandible rostrally, and ventrally, and is attached dorsally through frenulum linguae. A large number of papillae are present on its dorsal surface and the filiform (mechanical papillae) are most numerous. Other (gustatory papillae) including fungiform are scattered on the tips, circum vallate is located on the anterior root dorsally, and foliate on the sides of the tongue. The tongue executes functions like reception of dry leaves, mastication, and deglutition of food and the muscles of the intrinsic and extrinsic groups facilitate fodder movement inside the oral cavity [15, 46]. The group of muscles, including masseter muscle, internal pterygoid muscle, medial pterygoid muscle, and temporal muscles, are responsible for mastication.

### **7. Salivary glands**

In mammals, the main function of the salivary glands is to lubricate the ingested food, which helps in mastication and deglutition to protect oral tissues and in some species to initiate enzymatic activity. Salivary glands are present outside the wall of the digestive system and linked with the oral cavity through the duct. The two types of salivary glands include the major salivary glands and the minor salivary glands. The secretions of the salivary glands are serous, mucous, or seromucous

(mixed). Serous cells produce a watery secretion having enzymes, ions, and a small amount of mucin, whereas mucous cells produce a viscous, stringy secretion called mucus [15, 47].
