UPSC Animal Husbandry & Veterinary Science 2025 — Paper I

The directive 'write short notes' demands concise, information-dense responses for each sub-part within ~30 words per mark. Allocate approximately 30 words (20% time) per sub-part: for (a) focus on neural pathways and respiratory centers; for (b) emphasize programme components and funding; for (c) distinguish pre-natal (maternal, placental) from post-natal (nutrition, hormonal) factors; for (d) detail the AIV (Aho, Ilves, Valio) preservation mechanism and acid application; for (e) define EAAI formula and interpret values >1.0. No elaborate introduction or conclusion needed; begin each sub-part directly with definition or key mechanism.

• (a) Nervous control: Medullary respiratory centers (DRG/VRG), pontine centers, chemoreceptors (central-peripheral), Hering-Breuer reflex, and their integration in rhythmic breathing
• (b) NLHDCP: Components like ASCAD, NADCP, Brucellosis Control, PPR Eradication, funding pattern (60:40 Centre-State), and target species coverage
• (c) Growth factors: Pre-natal (maternal nutrition, placental efficiency, genetic imprinting) vs post-natal (colostrum intake, creep feeding, GH/thyroid axis, environmental temperature)
• (d) AIV method: Addition of mineral acids (HCl/H₂SO₄ mixture) to drop pH <4.0, rapid fermentation inhibition, suitability for low-sugar forages, dosage rate (3-5 litres/tonne)
• (e) EAAI: Formula using egg protein as reference, calculation of geometric mean of essential amino acid ratios, significance (EAAI>0.9=high quality, <0.5=poor), application in feed formulation

The directive 'discuss' requires critical examination with balanced coverage across all four sub-parts. Allocate approximately 35-40% time/words to part (a) given its 15 marks, 30% to part (b), and 15% each to parts (c) and (d). Structure with brief introductions for each sub-part, systematic body coverage, and integrated conclusions where analytical synthesis is possible.

• Part (a): Methods for calculating maintenance energy including factorial method (NEm = Fasting metabolism + Activity allowance), comparative slaughter technique, and respiration calorimetry; reference to NRC/ICAR standards for Indian conditions
• Part (b): Ionophores (monensin, lasalocid) effects on rumen fermentation: shift from acetate to propionate, reduced methane production, improved feed efficiency, and altered microbial population (Gram-positive inhibition)
• Part (c): Blood constituents—plasma (water, proteins, electrolytes) and formed elements (RBCs, WBCs, platelets); functions including oxygen transport, immune defense, clotting, and acid-base balance
• Part (d): Adrenal hormones—cortisol (gluconeogenesis, stress adaptation), aldosterone (Na+/K+ balance, blood pressure), adrenaline/noradrenaline (fight-flight, glycogenolysis); survival relevance during starvation, dehydration, and environmental stress
• Integration: Comparative physiological adaptations across species (cattle vs. buffalo vs. small ruminants) relevant to Indian livestock production systems

The question demands descriptive-narrative responses across three distinct domains: rural sociology (PRA techniques), behavioural science (ethology), and applied nutrition (dairy feeding). Allocate approximately 20% time/words to part (a) (10 marks), 40% to part (b) (20 marks), and 40% to part (c) (20 marks). Structure with brief introductions for each sub-part, systematic elaboration of techniques/behaviours/nutrients, and integrated conclusions that link theory to field application.

• Part (a): PRA techniques including Participatory Mapping, Transect Walks, Seasonal Calendars, Venn Diagrams, and Wealth Ranking with their specific applications in livestock-based rural planning
• Part (b): Precise definition of ethology distinguishing it from animal psychology; comprehensive classification of behaviours including ingestive, eliminative, sexual, maternal, social, agonistic, and thermoregulatory behaviours with species-specific examples
• Part (b): Detailed coverage of innate vs. learned behaviours, stereotypies, and their welfare implications in intensive production systems
• Part (c): Identification of limiting nutrients in high-yielding cows: energy (negative energy balance), protein (rumen undegradable protein), minerals (Ca, P, Mg, trace elements), and vitamins (A, D, E)
• Part (c): Strategic feeding approaches including phase feeding, TMR formulation, bypass nutrient technology, and transition cow management for metabolic disease prevention
• Integration: Link between PRA-identified local feed resources and strategic feeding; ethological considerations in housing design for high-yielding herds

The directive 'explain' demands clear, detailed exposition with causal reasoning and mechanism description. Allocate approximately 20% time/words to part (a) on hormonal receptors, 20% to part (b) on rumen carbohydrate digestion, 20% to part (c) on poultry feed intake factors, and 40% to part (d) covering all four short notes (5 marks each). Structure with brief introductions for each sub-part, systematic body coverage of all components, and concise summaries where analytical synthesis is possible.

• (a) Classification of hormonal receptors: membrane-bound (G-protein coupled, receptor tyrosine kinases, ion channel-linked) vs. intracellular (nuclear receptors); downstream signaling pathways (cAMP, IP3/DAG, JAK-STAT); specific functions in metabolic regulation, growth, and reproduction
• (b) Microbial carbohydrate digestion in ruminants: rumen microbial population (bacteria, protozoa, fungi); cellulolytic and amylolytic activity; volatile fatty acid production (acetate, propionate, butyrate); fermentation kinetics and energy yield; factors affecting microbial efficiency
• (c) Factors influencing voluntary feed intake in poultry: physiological factors (body weight, age, sex, strain); environmental factors (temperature, humidity, photoperiod); dietary factors (energy density, palatability, particle size, feed form); management factors (stocking density, feeder space, water availability)
• (d)(i) Amino acid imbalance in swine: antagonism (lysine-arginine), deamination and energy wastage, reduced growth performance, feed conversion ratio deterioration, correction through ideal protein concept and crystalline amino acid supplementation
• (d)(ii) Cerebrospinal fluid: production by choroid plexus, circulation pathway (ventricles → subarachnoid space → arachnoid villi), functions (shock absorption, nutrient transport, waste removal, intracranial pressure maintenance)
• (d)(iii) Reno-renal reflex: juxtaglomerular apparatus and macula densa sensing, tubuloglomerular feedback mechanism, renin-angiotensin-aldosterone system activation, autoregulation of glomerular filtration rate and sodium balance
• (d)(iv) General mineral functions: structural roles (Ca, P in bone), catalytic roles (Zn, Cu, Mn as enzyme cofactors), electrolyte balance (Na, K, Cl), acid-base regulation, oxygen transport (Fe), thyroid function (I, Se)

This multi-part question requires concise, structured responses of ~150 words each across five sub-topics. Allocate approximately 30 words per mark (150 words × 5 parts). For (a), contrast the two selection methods clearly; for (b), identify linkage and epistasis with brief descriptions; for (c), prioritize emergency feeding strategies; for (d), cover housing, breeding, and health in commercial rabbitry; for (e), distinguish in vivo (animal-level) from in vitro (laboratory-level) factors. Use bullet points or short paragraphs for clarity within each part.

• (a) Recurrent selection: repeated cycles of selection and intermating of selected individuals within a population; Reciprocal recurrent selection: simultaneous improvement of two populations by using each as tester for the other, exploiting both general and specific combining ability
• (b) Linkage (physical proximity of genes on same chromosome preventing independent assortment) and epistasis (non-allelic gene interaction masking expression); brief description of how each prevents random assortment
• (c) Drought feeding strategies: strategic culling, use of drought-tolerant fodder (sorghum, pearl millet), urea-molasses mineral blocks, silage utilization, restricted feeding, and water conservation techniques
• (d) Rabbit meat management: intensive housing (cages/hutches), commercial breeds (New Zealand White, California), accelerated breeding (re-mating at 14 days post-kindling), balanced pelleted diet, disease prevention (coccidiosis, pasteurellosis)
• (e) In vivo factors: nutrition, age, season, thermal stress, disease; In vitro factors: dilution rate, extender type (egg yolk-citrate, Tris), temperature, pH, osmotic pressure, microbial contamination, cryoprotectants (glycerol)

The directive 'describe' for part (a) and (c) and 'explain' for part (b) demand comprehensive coverage with technical precision. Allocate approximately 20% time/words to part (a) on heritability types, 40% to part (b) on semen collection methods given its higher marks and need for detail, and 40% to part (c) on heritability estimation methods. Structure with a brief introduction defining genetic variance and reproductive biotechnology, then address each sub-part sequentially with clear sub-headings, and conclude with integration of breeding theory and biotechnology application in Indian livestock improvement.

• Part (a): Broad-sense heritability (H² = VG/VP) vs narrow-sense heritability (h² = VA/VP) with components VG = VA + VD + VI and VP = VG + VE + VGE
• Part (a): Partitioning of genetic variance into additive (VA), dominance (VD), and epistatic (VI) components with their breeding significance
• Part (b): Artificial vagina method for bulls, rams, and bucks with temperature (40-42°C), pressure, and lubrication specifications
• Part (b): Electroejaculation, massage method, and AV adaptations for poultry (abdominal massage, dummy females, teaser males)
• Part (c): ANOVA-based methods including half-sib, full-sib, and parent-offspring regression with Falconer's formulae
• Part (c): REML (Restricted Maximum Likelihood) and Bayesian methods for complex pedigrees; comparison of precision and bias
• Part (c): Indian examples: heritability estimates for milk yield in Sahiwal, Karan-Fries; semen collection protocols at NDRI Karnal and ICAR-CIRC Meerut

The directive 'illustrate' in part (b) demands visual/diagrammatic representation with systematic explanation, while parts (a) and (c) require descriptive-analytical treatment. Allocate approximately 40% of time/words to part (a) given its 20 marks weightage, with 30% each to parts (b) and (c). Structure: Introduction defining mixed farming and population genetics concepts → Body with detailed treatment of each sub-part using diagrams for (b) → Conclusion synthesizing how integrated dairy systems and genetic improvement converge in Indian livestock development.

• Part (a): Definition and characteristics of dairying under mixed farming (crop-livestock integration, smallholder systems, use of crop residues and manure recycling); comparison with specialized dairy farming (capital intensity, scale, feed dependency, market orientation); India-specific advantages: risk distribution, resource use efficiency, employment generation, suitability for marginal farmers, organic manure availability, and resilience against price volatility
• Part (b): Hardy-Weinberg equilibrium as baseline; systematic factors changing gene/genotype frequencies: mutation, migration/gene flow, genetic drift (founder effect, bottleneck), natural selection (directional, stabilizing, disruptive), and artificial selection; mating systems (assortative, disassortative, inbreeding, outbreeding); diagrammatic representation of selection response and changes in allelic frequencies over generations
• Part (c): Socio-economic dimensions of layer poultry: backyard vs. commercial systems; role in women empowerment and nutritional security; contract farming models (Suguna, Venkateshwara); regional disparities (Andhra Pradesh, Tamil Nadu dominance); feed cost-price squeeze; disease outbreaks (Avian Influenza) and biosecurity economics; government schemes (Rural Backyard Poultry Development, NADCP)
• Integration point: How mixed farming dairy and poultry egg production represent complementary livelihood strategies in Indian smallholder agriculture, with population genetics principles underlying breed improvement in both sectors
• Critical analysis: Challenges facing mixed farming dairy (declining grazing lands, labour shortage) and socio-economic barriers in poultry (middlemen exploitation, market access for small producers)

The directive 'classify' in part (a) demands systematic categorization with clear headings and sub-headings; parts (b) and (c) require 'mention' and 'give an account' respectively, calling for descriptive precision. Allocate approximately 40% of time/words to part (a) given its 20 marks, 30% each to parts (b) and (c). Structure with a brief introduction on dairy economics and breeding importance, then three distinct sections for each sub-part, and a concluding synthesis on integrated dairy farm management.

• Part (a): Investment classification into fixed (land, building, equipment, milch animals) and working capital (feed, fodder, labor, veterinary expenses); receipts from milk sales, manure, calves, and cull animals; expenditure on feed (60-70%), labor, breeding, healthcare, and miscellaneous overheads
• Part (a): Economic indicators like cost of milk production, net income per cow, benefit-cost ratio, and break-even analysis for commercial viability assessment
• Part (b): Estrus signs in cattle (mounting, bellowing, mucus discharge, swollen vulva) and buffaloes (silent estrus, reduced feed intake, restlessness, characteristic vocalization); optimal AI timing at 12-24 hours after onset in cattle and 18-24 hours in buffaloes due to ovulation patterns
• Part (b): Scientific rationale for timing based on ovulation occurring 24-32 hours post-estrus onset, sperm capacitation time, and egg viability window
• Part (c): Individual selection based on own phenotype and breeding value; family selection using full-sib and half-sib averages; within-family selection removing family mean effects to exploit Mendelian sampling variance
• Part (c): Comparison of selection methods with respect to heritability, accuracy of genetic evaluation, and applicability in dairy cattle breeding programs under Indian conditions