• Pathogenesis of Primary Tympany (Frothy Bloat): Primary ruminal tympany is a nutritional disorder caused by the excessive ingestion of lush, immature, rapidly growing legumes (such as alfalfa, red clover, and ladino clover) or young winter wheat pastures.
• Biochemical Froth Formation: These forages contain high concentrations of soluble chloroplast proteins (particularly 18S fraction I protein) and saponins. Rapid microbial fermentation releases these foaming agents, creating a persistent, stable, viscous foam that traps fermentation gases ($\text{CO}_2$ and $\text{CH}_4$). The foam covers the cardia, inhibiting the eructation reflex and leading to life-threatening ruminal distension.
• Secondary Tympany (Free-Gas Bloat): Caused by mechanical or functional esophageal obstruction (choke, tumors, papillomas, vagal indigestion).

Correct option: (3) Excessive feeding of legumes

• Avian Spirochaetosis Hallmarks:
• Etiology: Caused by the pathogenic, motile helical spirochete Borrelia anserina [TRUE].
• Vector Transmission: Transmitted biological and transovarially by the soft fowl tick Argas persicus [TRUE].
• Morbidity & Mortality: Causes acute septicemic disease in chickens, geese, and turkeys characterized by high fever, severe depression, greenish diarrhea, and high flock mortality [TRUE].
• Splenic Lesions: Marked splenomegaly where the spleen is enlarged $4\text{--}6$ times with characteristic petechiae and white-gray necrotic mottling throughout the red pulp, imparting a pathognomonic mottled appearance [TRUE].

Correct option: (3) (A), (B), (C) and (D).

• Infectious Bovine Rhinotracheitis (IBR) Biology:
• Etiology: Caused by Bovine Alphaherpesvirus 1 (BoHV-1) [Statement 1 is TRUE].
• Respiratory Lesions: Produces severe necrotizing diphtheritic tracheitis, rhinitis, and bronchopneumonia [Statement 2 is TRUE].
• 'Red Nose': Severe hyperemia, necrosis, and crusting of the muzzle and external nares gives the condition its common name 'Red Nose' [Statement 4 is TRUE].
• Inclusion Body Characteristics: Like all herpesviruses, BoHV-1 replicates within the host cell nucleus, producing diagnostic intra-NUCLEAR inclusion bodies (Cowdry Type A) in respiratory epithelial cells, NEVER intra-cytoplasmic inclusions [Statement 3 is FALSE].

Correct option: (3) Characteristic intra-cytoplasmic inclusions are seen in the tracheal epithelium

• Equine Pinworm Pathology: Oxyuris equi is the common pinworm of horses and equids residing in the caecum, colon, and rectum.
• Pathogenesis of Anal Pruritus: Gravid female worms crawl out through the anal sphincter to deposit millions of eggs in a sticky, yellowish-white gelatinous fluid onto the perianal skin and perineum. Desiccation of this fluid causes intense perianal pruritus (pruritus ani), compelling the horse to rub its hindquarters against fences and walls, resulting in broken tail hair and the classical 'rat-tail' (pipe-tail) appearance.
• Contrasting Parasites:
• Parascaris equorum: Equine ascarid causing impaction in foals.
• Strongylus vulgaris: Causes verminous arteritis of the cranial mesenteric artery.
• Trichuris vulpis: Canine whipworm.

Correct option: (4) Oxyuris equi