(a)(i) Elucidate the etiology, pathogenesis, clinical findings and line of treatment of esophagitis in cow. (10 marks) (a)(ii)…

(a)(i) Esophagitis in Cattle

Esophagitis is an inflammation of the esophageal mucosa. Causes are traumatic (sharp feed or foreign bodies such as wire, and rough use of a probang, stomach tube or balling gun), chemical (ingestion of caustic or irritant substances, very hot or irritant drenches), and infectious or parasitic: the erosive and ulcerative viral diseases (BVD–mucosal disease, IBR, malignant catarrhal fever, bluetongue, FMD) produce esophageal erosions, and Hypoderma bovis larvae migrate through the esophageal submucosa. Pathogenesis involves mucosal injury leading to local inflammation, edema, and ulceration or necrosis; secondary bacterial infection (e.g. Fusobacterium necrophorum) follows, and deep injury can cause perforation with cellulitis or abscess of the neck, while healing by fibrosis may leave a stricture. Clinically, affected cows exhibit dysphagia, regurgitation of feed, excessive salivation, and pain upon palpation of the cervical region. Swelling may be palpable along the neck. Treatment depends on etiology: remove any accessible foreign body; withhold oral feed for a few days and maintain hydration with parenteral fluids and electrolytes (avoid passing a stomach tube); give broad-spectrum systemic antibiotics (e.g. procaine penicillin or oxytetracycline) against secondary infection, and drain any cervical abscess surgically. Supportive care includes NSAIDs for pain and inflammation and a soft, moistened, palatable diet when feeding resumes; the underlying viral disease is managed as a herd problem, and animals are monitored for stricture.

(a)(ii) Iodine Supplementation in Livestock

Iodine is an essential micronutrient required for the synthesis of thyroid hormones, triiodothyronine (T3) and thyroxine (T4), which regulate metabolism, growth, and reproduction. In iodine-deficient regions, such as the Himalayan "Goiter Belt" in India, livestock are prone to hypothyroidism. Deficiency manifests as endemic goitre, reproductive failures including retained placenta and anestrus, and the birth of weak, premature, or stillborn offspring with abnormal hair coats. Other effects include hairless piglets, poor wool growth in sheep, reduced milk yield and lowered growth rate. Requirements rise when goitrogens are fed: glucosinolates in rapeseed–mustard cake and brassica fodders (cabbage, turnip), and thiocyanate from cyanogenic feeds such as linseed and white clover. The dairy-cow requirement is about 0.5 mg iodine per kg dietary dry matter (NRC), with a higher allowance when goitrogens are present. Because most Indian roughages and grains are low in iodine, and because iodine in milk also reaches human consumers, dietary supplementation is essential to prevent these conditions and the production losses they cause. Excess must be avoided, since iodine toxicity causes lacrimation, coughing and scaly skin. Preventive dosing via iodised salt, area-specific mineral mixtures or salt licks is critical in endemic areas to maintain herd health and productivity.

(b)(i) Femur Fracture Repair in Murrah Buffalo

Femoral fractures in an adult Murrah buffalo (often 450–600 kg) carry a guarded prognosis, because the heavy muscle mass makes reduction difficult and implants must withstand very large loads; the owner should be counselled about cost and outcome. Pre-operatively, the animal is stabilised, the limb is supported, and orthogonal radiographs define the fracture configuration. A Thomas splint–cast or external coaptation alone is not adequate for a mid-shaft femur fracture in an adult, because the femur is enclosed in muscle and the joint above cannot be immobilised.

Under general anaesthesia (e.g. xylazine–ketamine induction with inhalant maintenance, supplemented by epidural analgesia) in lateral recumbency, the femoral shaft is exposed by a craniolateral approach between the biceps femoris and vastus lateralis. Haematoma and debris are removed and the fragments are brought into open reduction, often requiring traction and bone-holding forceps. Stable internal fixation is essential: an interlocking intramedullary nail, or one or two dynamic or locking compression plates placed at right angles, with cerclage wires for oblique fragments; a plain intramedullary pin alone does not control rotation and usually fails in an adult. Cancellous bone graft may be packed into any defect.

Post-operatively, the buffalo is confined to a small pen with a non-slip, well-bedded floor and slings if needed, given antibiotics for 5–7 days and NSAIDs for pain, and is watched for implant failure, infection, and pressure sores or overload laminitis in the opposite limb. Weight-bearing is increased gradually as serial radiographs show callus bridging, usually over 8–12 weeks.

(b)(ii) Factors Leading to Non-Union

Non-union of broken bones results from a combination of biological, mechanical, and patient-related factors. Biologically, poor blood supply to the fracture site, active infection, or inadequate soft tissue coverage impedes healing. Mechanically, excessive gap between bone fragments, instability due to inadequate fixation, or premature weight-bearing disrupts the healing process. Patient-related factors include advanced age, poor nutritional status (deficiencies in calcium, phosphorus, or protein), and metabolic diseases like hyperparathyroidism. Iatrogenic causes, such as aggressive debridement that removes periosteum or improper surgical technique, also contribute significantly to non-union.

(c) Gross Anatomy of Ovary and Oviduct in Fowl

Only the left ovary and oviduct are functional in the hen (the right regresses during embryonic life). The ovary lies at the cranial end of the left kidney, attached by the mesovarium; in the laying hen it resembles a bunch of grapes, with follicles hanging on stalks from its surface. Follicles are present at every stage in a size hierarchy, from small white follicles to five or six large yellow yolk-filled follicles, the largest being the next to ovulate. Each follicle ruptures along an avascular band, the stigma. Unlike mammals, there is no persistent corpus luteum graviditatis; the post-ovulatory follicle has only transient endocrine function.

The oviduct of a laying hen is a long, coiled, muscular tube (about 65–70 cm) divided into five distinct segments, each with specific secretory functions. The infundibulum is the funnel-shaped initial segment with fimbriae that capture the ovulated oocyte; fertilisation takes place here and the chalazae begin to form (about 15–30 minutes). The magnum is the longest segment, responsible for secreting the bulk of the albumen (egg white) in about 3 hours. The isthmus is a narrow segment where the inner and outer shell membranes are synthesized from proteins like collagen and glycoproteins. The uterus (or shell gland) is the widest segment, where the egg spends about 20 hours: water and salts are added to the albumen (plumping), the calcareous shell is deposited, pigments are added, and the cuticle is laid down just before laying. Finally, the vagina is the terminal segment, through which the egg passes to the cloaca during oviposition; it is not a copulatory organ (mating is by cloacal contact), and sperm-host glands at the utero-vaginal junction store sperm for one to two weeks. It does not secrete the shell cuticle, which is formed in the uterus.

A labelled schematic of the ovary and oviduct with the secretory role of each segment is shown below: