(a) Development of pituitary gland (10 marks) (b) Boundaries of thoracic and pelvic cavities of bovines and organs present…

(a) Development of pituitary gland

The pituitary has a double origin. Rathke's pouch, an upgrowth of the oral ectoderm (stomodeum) roof, grows dorsally towards the infundibulum, a downgrowth of the neuroectoderm of the diencephalic floor. The pouch loses its connection with the mouth and is cut off, and its lumen narrows to the residual cleft. Its anterior wall thickens to form the pars distalis, its posterior wall forms the pars intermedia, and lateral extensions wrap the stalk as the pars tuberalis; together these are the adenohypophysis. The infundibulum forms the neurohypophysis: the pars nervosa, infundibular stem and median eminence. The adenohypophysis receives the hypophyseal portal vessels from the median eminence, and the gland settles in the sella turcica (pituitary fossa) of the basisphenoid bone. Failure of development causes congenital hypopituitarism and dwarfism; remnants of the pouch may give craniopharyngioma.

(b) Boundaries of thoracic and pelvic cavities of bovines and organs present

Thoracic cavity: cranially the thoracic inlet (first thoracic vertebra, first ribs and manubrium), caudally the diaphragm, dorsally the thoracic vertebrae, laterally the ribs and intercostal muscles, ventrally the sternum. The mediastinum divides it into two pleural sacs holding the lungs; the mediastinum contains the heart in the pericardium, trachea, oesophagus, thoracic aorta, vena cava, thoracic duct, vagus and phrenic nerves, lymph nodes and the thymus in young animals.

Pelvic cavity: dorsally the sacrum and first caudal vertebrae, laterally the ilium and sacrosciatic ligament, ventrally the pubis and ischium; the pelvic inlet is cranial and the outlet caudal. It holds the rectum, urinary bladder and pelvic urethra. In the cow it also holds the vagina, vestibule and caudal cervix, and in the bull the accessory sex glands (vesicular glands, prostate and bulbourethral glands) and the pelvic part of the vas deferens.

(c) Diagnosis and treatment of epilepsy in dogs

Diagnosis: epilepsy means recurrent seizures, and it is diagnosed by exclusion. A history records age, seizure type, frequency and triggers; idiopathic epilepsy usually starts at 6 months to 6 years. Physical and neurological examination, blood count, biochemistry (glucose, calcium, liver function, bile acids), urinalysis and blood pressure exclude metabolic and toxic causes. MRI and cerebrospinal fluid analysis are done for structural, inflammatory or infectious disease, especially with abnormal neurology, onset before 6 months or after 6 years, and EEG is supportive.

Treatment: antiepileptic therapy is advised for clusters, status epilepticus or frequent seizures. Phenobarbital is first line (about 2.5 mg/kg twice daily), with serum level and liver monitoring; potassium bromide or levetiracetam or imepitoin is added or used instead. Status epilepticus is treated with intravenous or rectal diazepam. The owner keeps a seizure diary.

(d) Measures to assess environmental pollution

Assessment combines physical, chemical and biological measures.

• Air: sampling for particulate matter (PM10, PM2.5), SO₂, NOx, CO and ozone, reported as an Air Quality Index.
• Water: pH, dissolved oxygen, BOD, COD, total dissolved solids, nitrates, heavy metals and coliform counts.
• Soil: pH, salinity, organic matter, heavy metals and pesticide residues.
• Biological: bioindicators such as lichens for air and macroinvertebrates or fish for water, and biomonitoring with sentinel animals.
• Residue analysis of milk, meat and feed for pesticides, heavy metals and drug residues against standards (FSSAI limits).
• Noise meters, and remote sensing and GIS for mapping.

The Central Pollution Control Board runs the national monitoring networks.

(e) Milk fever and its management in dairy cows

Milk fever (parturient paresis) is hypocalcaemia in high-yielding cows, mostly within 72 hours after calving, when colostrum synthesis drains calcium faster than bone and gut can replace it. Blood calcium falls below about 5.5 mg/dl and muscle and nerve function fail.

Signs: restlessness and tremors (stage 1), then the cow is down, with sternal recumbency, S-shaped neck, cold extremities, dry muzzle, poor anal tone, tympany and weak pulse (stage 2), then lateral recumbency and coma (stage 3).

Treatment: slow intravenous 23% calcium borogluconate, about 400–500 ml (1 g of calcium per 45 kg body weight) over 10–20 minutes with the heart auscultated, since rapid injection causes arrhythmia; subcutaneous or oral calcium follows to avoid relapse. Magnesium and phosphorus are given where low.

Prevention: a low-calcium or negative-DCAD ration in the last three weeks of pregnancy, adequate magnesium, and vitamin D or oral calcium at calving.