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PSSSB Veterinary Inspector study materials
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PSSSB Veterinary Inspector practice questions

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Question 1Animal Anatomy, Physiology and Histology

In the ruminant stomach, which compartment is lined by a keratinized stratified squamous epithelium and functions mainly as a fermentation vat?

  1. Reticulum
  2. Omasum
  3. Abomasum
  4. Rumen Correct answer.

Explanation

The rumen is lined by keratinized stratified squamous epithelium and houses the dense microbial population that ferments cellulose. The abomasum is the glandular true stomach, the omasum absorbs water and volatile fatty acids, and the reticulum has a honeycomb mucosa involved in regurgitation.

Question 2Animal Anatomy, Physiology and Histology

The functional unit of the kidney in domestic mammals is the nephron. Which segment is the principal site of glucose and amino acid reabsorption?

  1. Thin limb of the loop of Henle
  2. Proximal convoluted tubule Correct answer.
  3. Distal convoluted tubule
  4. Collecting duct

Explanation

The proximal convoluted tubule, with its brush border and abundant mitochondria, reabsorbs nearly all filtered glucose, amino acids and much sodium. The thin limb is water-permeable but reabsorbs little solute, the distal tubule handles sodium and potassium under hormonal control, and the collecting duct fine-tunes water balance.

Question 3Animal Anatomy, Physiology and Histology

Which formed element of ruminant blood is anucleate, biconcave and the most numerous, carrying oxygen via hemoglobin?

  1. Neutrophil
  2. Thrombocyte
  3. Erythrocyte Correct answer.
  4. Lymphocyte

Explanation

Mature erythrocytes of domestic mammals are anucleate biconcave discs packed with hemoglobin and are the most abundant blood cells. Neutrophils and lymphocytes are nucleated leukocytes, and thrombocytes are small platelets involved in hemostasis.

Question 4Animal Anatomy, Physiology and Histology

The sinoatrial node of the heart is located in which region and acts as the cardiac pacemaker?

  1. Wall of the left ventricle near the aortic valve
  2. Base of the pulmonary trunk
  3. Interventricular septum near the apex
  4. Wall of the right atrium near the opening of the cranial vena cava Correct answer.

Explanation

The sinoatrial node lies in the wall of the right atrium at the junction with the cranial vena cava and depolarizes spontaneously to set heart rate. The atrioventricular node sits in the interatrial septum and delays conduction, while the Purkinje network distributes impulses through ventricular walls.

Question 5Animal Anatomy, Physiology and Histology

Which layer of the tubular digestive tract lies immediately beneath the mucosa and contains blood vessels, lymphatics and glands in some regions?

  1. Serosa
  2. Mucosa
  3. Submucosa Correct answer.
  4. Muscularis externa

Explanation

The submucosa is the loose connective tissue layer beneath the mucosa carrying vessels, nerves and sometimes glands such as Brunner's glands. The muscularis externa provides peristalsis, the serosa is the outer covering, and the mucosa is the innermost lining.

Question 6Animal Anatomy, Physiology and Histology

In the avian respiratory system, air flows through the lungs during both inspiration and expiration mainly because of which structure?

  1. Diaphragm
  2. Alveolar surfactant
  3. Air sacs acting as bellows Correct answer.
  4. Intercostal muscles alone

Explanation

Birds lack a diaphragm, and the air sacs act as bellows that keep air moving unidirectionally through the rigid parabronchial lungs during both inspiration and expiration. Alveoli and surfactant are mammalian features, and intercostal muscles alone cannot sustain continuous flow.

Question 7Animal Anatomy, Physiology and Histology

Which connective tissue type forms tendons and is characterized by dense parallel collagen bundles with sparse fibroblasts?

  1. Reticular connective tissue
  2. Hyaline cartilage
  3. Dense regular connective tissue Correct answer.
  4. Adipose tissue

Explanation

Dense regular connective tissue has collagen fibers arranged in parallel bundles with few fibroblasts, giving high tensile strength along one axis, as in tendons. Hyaline cartilage is a firm matrix with chondrocytes, adipose stores lipid, and reticular tissue forms supportive networks in lymphoid organs.

Question 8Animal Anatomy, Physiology and Histology

During the estrous cycle of the mare, ovulation occurs approximately how long before the end of estrus?

  1. 7 days before the end of estrus
  2. At the onset of diestrus
  3. Immediately after luteolysis
  4. 24 to 48 hours before the end of estrus Correct answer.

Explanation

In the mare, ovulation typically occurs about 24 to 48 hours before the end of behavioral estrus, so mares may still show estrus after ovulation. Luteolysis precedes the next follicular phase, and diestrus follows ovulation under progesterone dominance.

Question 9Animal Anatomy, Physiology and Histology

A cow is presented with rumen stasis. Which anatomical feature most directly explains the close relationship between rumen and reticulum function?

  1. A separate sphincter isolating the reticulum
  2. A complete septum separating the two compartments
  3. A common rumenoreticular fold allowing shared contractions Correct answer.
  4. Absence of papillae in the reticulum

Explanation

The rumen and reticulum share the rumenoreticular fold and contract together in the mixing cycle, so dysfunction of one readily affects the other. They are not completely separated by a septum or sphincter, and the reticulum bears a honeycomb crest pattern rather than lacking surface features.

Question 10Animal Anatomy, Physiology and Histology

In a histological section of the thyroid gland, which feature distinguishes it from parathyroid tissue?

  1. Sinusoids containing islets
  2. Cords of cells without follicles
  3. Follicles lined by epithelium containing colloid Correct answer.
  4. Hassall's corpuscles

Explanation

The thyroid is uniquely organized into follicles lined by cuboidal epithelium and filled with colloid (thyroglobulin). The parathyroid consists of solid cords of chief cells without follicles, Hassall's corpuscles occur in the thymus, and islets are pancreatic endocrine clusters.

Question 11Animal Anatomy, Physiology and Histology

Which statement correctly describes the difference between the pulmonary and systemic circulations in the mammalian heart?

  1. The left ventricle pumps deoxygenated blood to the lungs
  2. The pulmonary artery carries oxygenated blood to the body
  3. The right ventricle pumps deoxygenated blood to the lungs at lower pressure Correct answer.
  4. The right atrium receives oxygenated blood from the lungs

Explanation

The right ventricle drives the pulmonary circuit with deoxygenated blood at lower pressure, while the thicker-walled left ventricle pumps oxygenated blood into the systemic circulation. The pulmonary artery carries deoxygenated blood to the lungs, and the right atrium receives systemic venous blood.

Question 12Animal Anatomy, Physiology and Histology

Which type of muscle tissue is involuntary, striated and found only in the heart?

  1. Skeletal muscle
  2. Myoepithelium
  3. Cardiac muscle Correct answer.
  4. Smooth muscle

Explanation

Cardiac muscle is striated yet involuntary, with intercalated discs and branched fibers unique to the heart. Skeletal muscle is striated but voluntary, smooth muscle is involuntary but non-striated, and myoepithelium is a contractile epithelial derivative.

Question 13Animal Anatomy, Physiology and Histology

In the male reproductive tract, which structure is the primary site of sperm maturation and storage before ejaculation?

  1. Prostate gland
  2. Seminiferous tubule
  3. Epididymis Correct answer.
  4. Vas deferens

Explanation

Sperm acquire motility and fertilizing capacity while passing through and being stored in the epididymis. Seminiferous tubules produce sperm, the prostate contributes seminal fluid, and the vas deferens transports sperm during ejaculation.

Question 14Animal Anatomy, Physiology and Histology

Which component of the avian integument produces the contour feathers and is anchored in a dermal follicle?

  1. Sebaceous gland
  2. Sweat gland
  3. Feather follicle Correct answer.
  4. Hoof

Explanation

Each feather develops from a dermal papilla within a feather follicle and is keratinized into a shaft and vanes. Birds lack sweat glands, sebaceous glands are sparse and associated with the uropygial gland, and hooves are ungulate keratin structures.

Question 15Animal Anatomy, Physiology and Histology

A dog with a portosystemic shunt shows elevated blood ammonia. Which anatomical arrangement normally ensures hepatic first-pass metabolism of portal blood?

  1. Lymphatic drainage bypassing the liver
  2. Portal vein emptying directly into systemic veins
  3. Hepatic artery draining into the caudal vena cava
  4. Portal vein draining into hepatic sinusoids before hepatic veins Correct answer.

Explanation

The portal vein normally delivers intestinal blood to hepatic sinusoids, where hepatocytes metabolize ammonia before blood exits via hepatic veins. A shunt connects portal to systemic circulation, bypassing this first-pass clearance. The hepatic artery supplies oxygenated blood, not intestinal venous return.

Question 16Animal Anatomy, Physiology and Histology

Which histological feature identifies the small intestine rather than the large intestine?

  1. Abundant goblet cells with crypts only
  2. Villi projecting into the lumen Correct answer.
  3. Teniae coli
  4. Haustra

Explanation

Finger-like villi that increase absorptive surface are characteristic of the small intestine. The large intestine lacks villi, has numerous goblet cells, and in many species shows teniae coli and haustra.

Question 17Animal Anatomy, Physiology and Histology

In the estrous cycle, which hormone surge directly triggers ovulation?

  1. Progesterone
  2. Prolactin
  3. Oxytocin
  4. Luteinizing hormone Correct answer.

Explanation

A preovulatory surge of luteinizing hormone from the anterior pituitary triggers follicular rupture and ovulation. Progesterone dominates the luteal phase and suppresses ovulation, prolactin supports lactation, and oxytocin acts on smooth muscle during parturition and milk ejection.

Question 18Animal Anatomy, Physiology and Histology

Which spinal nerve component carries motor fibers to skeletal muscle and is identified by its ventral root origin?

  1. Dorsal root
  2. Dorsal root ganglion
  3. Sympathetic trunk
  4. Ventral root Correct answer.

Explanation

The ventral root contains efferent motor axons leaving the spinal cord for skeletal muscle. The dorsal root carries afferent sensory fibers, its ganglion holds sensory neuron cell bodies, and the sympathetic trunk is a paravertebral ganglion chain.

Question 19Animal Anatomy, Physiology and Histology

Which cell type lines the alveoli and produces surfactant to reduce surface tension?

  1. Type I pneumocyte
  2. Alveolar macrophage
  3. Type II pneumocyte Correct answer.
  4. Endothelial cell

Explanation

Type II pneumocytes are cuboidal cells that secrete surfactant, lowering alveolar surface tension and preventing collapse. Type I pneumocytes form the thin gas-exchange barrier, macrophages phagocytose debris, and endothelial cells line capillaries.

Question 20Animal Anatomy, Physiology and Histology

Which feature of the camelid erythrocyte is correctly described as an adaptation seen in these species?

  1. Presence of a cell wall
  2. Nucleated mature form
  3. Elliptical shape Correct answer.
  4. Absence of hemoglobin

Explanation

Camelid erythrocytes are characteristically elliptical rather than round, an adaptation noted in these species. Mature mammalian erythrocytes are anucleate and lack a cell wall, and they contain hemoglobin for oxygen transport.

Question 21Animal Anatomy, Physiology and Histology

In a histology slide, a gland shows acini with basally located nuclei and apical zymogen granules. Which secretion mechanism and gland type is most consistent?

  1. Endocrine secretion into sinusoids
  2. Holocrine secretion from a sebaceous gland
  3. Merocrine secretion from a serous acinar gland Correct answer.
  4. Apocrine secretion from a mucous gland

Explanation

Basal nuclei with apical zymogen granules indicate serous acinar cells releasing enzyme-rich product by merocrine exocytosis, as in the pancreas. Mucous glands have pale apical mucin, sebaceous glands release whole cells holocrine, and endocrine glands lack ducts and secrete into blood.

Question 22Animal Anatomy, Physiology and Histology

A horse in training shows increased packed cell volume due to splenic contraction. Which mechanism best explains this splenic response?

  1. Sympathetic-mediated contraction expelling stored erythrocytes into circulation Correct answer.
  2. Parasympathetic stimulation increasing erythropoiesis acutely
  3. Direct filtration of plasma by the spleen
  4. Immediate release of new erythrocytes from bone marrow

Explanation

The spleen stores a reservoir of erythrocytes, and sympathetic stimulation during exercise or stress contracts the capsule to expel them, raising packed cell volume within minutes. This is not new marrow production, which takes days, and parasympathetic activity does not drive splenic contraction.

Question 23Animal Anatomy, Physiology and Histology

In the kidney, the countercurrent multiplier depends on which arrangement of the loop of Henle?

  1. Descending limb water-permeable and ascending limb actively transporting sodium chloride Correct answer.
  2. Both limbs freely permeable to water
  3. Descending limb actively secreting glucose
  4. Ascending limb permeable to water and impermeable to solute

Explanation

The descending limb is permeable to water but not solute, while the ascending limb actively transports sodium chloride and is relatively water-impermeable. This countercurrent arrangement builds the medullary osmotic gradient that concentrates urine.

Question 24Animal Anatomy, Physiology and Histology

During the cardiac cycle, closure of the atrioventricular valves produces which heart sound?

  1. Fourth heart sound
  2. Third heart sound
  3. First heart sound Correct answer.
  4. Second heart sound

Explanation

The first heart sound arises from closure of the atrioventricular valves at the onset of ventricular systole. The second sound reflects semilunar valve closure, while third and fourth sounds relate to ventricular filling and atrial contraction.

Question 25Animal Nutrition and Feed Management

In ruminant nutrition, the term 'bypass protein' refers to dietary protein that:

  1. Is synthesized by rumen microbes from non-protein nitrogen
  2. Escapes ruminal degradation and is digested in the small intestine Correct answer.
  3. Remains undigested and is excreted in the faeces
  4. Is degraded rapidly by rumen microbes into ammonia

Explanation

Bypass protein, also called rumen-undegradable protein (RUP), passes through the rumen without being fermented by microbes and is then digested and absorbed in the abomasum and small intestine. It supplies amino acids directly to the animal, complementing microbial protein. Rapidly degraded protein is the opposite category (RDP).

Question 26Animal Nutrition and Feed Management

The primary role of roughage in the diet of a dairy cow is to:

  1. Supply most of the dietary phosphorus
  2. Maintain rumen pH and stimulate chewing and rumination Correct answer.
  3. Provide the main source of bypass amino acids
  4. Increase the energy density of the ration

Explanation

Roughages are high in fibre, which promotes chewing, saliva production and rumination, and supports a healthy rumen microbial population that keeps rumen pH stable. Fibre is fermented slowly to acetate, which is important for milk fat synthesis. Energy density and bypass amino acids come mainly from concentrates.

Question 27Animal Nutrition and Feed Management

A feed sample contains 88% dry matter. On a dry matter basis, the crude protein content is 20%. What is the crude protein content on an as-fed basis?

  1. 22.7%
  2. 20.0%
  3. 17.6% Correct answer.
  4. 8.8%

Explanation

To convert from a dry matter basis to an as-fed basis, multiply by the dry matter fraction: 20% × 0.88 = 17.6%. As-fed values are always lower than dry matter values because water dilutes the nutrient. This conversion is essential when formulating rations from feed analysis reports.

Question 28Animal Nutrition and Feed Management

Which mineral deficiency is most classically associated with 'pica' (depraved appetite) and poor growth in grazing cattle?

  1. Selenium
  2. Iodine
  3. Phosphorus Correct answer.
  4. Copper

Explanation

Phosphorus deficiency in grazing livestock commonly causes pica, in which animals chew bones, wood or soil, along with poor growth, stiff gait and reduced fertility. Phosphorus is required for bone formation and energy metabolism. Other minerals cause different, more specific syndromes.

Question 29Animal Nutrition and Feed Management

A concentrate mixture is being balanced for a growing calf. Which feed ingredient is the richest plant source of energy per unit weight among the following?

  1. Maize grain Correct answer.
  2. Wheat bran
  3. Lucerne hay
  4. Groundnut cake

Explanation

Maize grain is a cereal rich in starch and contains roughly 3.3 to 3.4 Mcal of metabolisable energy per kg on a dry matter basis, making it one of the highest-energy plant feeds. Wheat bran is more fibrous, while groundnut cake is a protein supplement and lucerne hay is a forage. Energy density therefore ranks maize highest.

Question 30Animal Nutrition and Feed Management

Urea can be used as a non-protein nitrogen source in ruminant diets mainly because rumen microbes:

  1. Directly absorb intact urea and use it to build body protein
  2. Hydrolyse urea to ammonia and incorporate it into microbial protein Correct answer.
  3. Convert urea into bypass protein in the abomasum
  4. Use urea as an energy source for volatile fatty acid production

Explanation

Rumen microbes possess urease, which hydrolyses urea to ammonia; the ammonia is then used with available carbon skeletons and energy to synthesise microbial protein. Urea supplies nitrogen, not energy, so it must be fed with readily fermentable carbohydrates. Overfeeding urea risks ammonia toxicity.

Question 31Animal Nutrition and Feed Management

Silage that has fermented poorly and smells strongly of butyric acid most likely indicates:

  1. A clostridial fermentation with excessive protein breakdown Correct answer.
  2. Excessive wilting before ensiling
  3. A successful lactic acid fermentation
  4. A high sugar content in the forage

Explanation

Butyric acid and a putrid smell indicate clostridial fermentation, which occurs when the pH does not fall quickly enough, often due to low sugar or high moisture. Clostridia break down proteins and produce butyric acid, reducing silage quality and palatability. Well-made silage has a low pH dominated by lactic acid and a pleasant acidic odour.

Question 32Animal Nutrition and Feed Management

The Pearson square method is used in ration formulation to:

  1. Determine the proportion of two feeds needed to achieve a target nutrient concentration Correct answer.
  2. Calculate the digestibility of a feed from faecal output
  3. Determine the amino acid profile of a protein supplement
  4. Estimate the dry matter intake of a herd

Explanation

The Pearson square is a simple algebraic tool that mixes two feeds to reach a desired nutrient percentage, such as a target crude protein level. The difference between each feed's value and the target gives the parts of each feed to combine. It is widely used for balancing energy or protein in practical rations.

Question 33Animal Nutrition and Feed Management

Which vitamin is synthesized in sufficient quantity by rumen microbes and therefore rarely needs supplementation in adult ruminants fed a normal diet?

  1. Vitamin D
  2. Vitamin B complex Correct answer.
  3. Vitamin A
  4. Vitamin E

Explanation

Adult ruminants generally synthesise adequate B-complex vitamins through rumen microbial activity, so deficiency is uncommon unless the rumen function is impaired. Vitamins A, D and E are not synthesized in adequate amounts and must be supplied through feed or, for vitamin D, sunlight exposure. Young pre-ruminant calves may still need B-vitamin supplementation.

Question 34Animal Nutrition and Feed Management

In poultry, the metabolisable energy of a feed is best described as:

  1. Gross energy minus energy lost in faeces, urine and gaseous products Correct answer.
  2. The energy retained in body tissue only
  3. The energy lost as heat during digestion
  4. The total heat of combustion of the feed

Explanation

Metabolisable energy (ME) is the gross energy of the feed minus the energy voided in faeces, urine and gaseous losses. It represents the energy available to the bird for maintenance and production. In poultry, ME is the standard system because urinary and faecal outputs are voided together.

Question 35Animal Nutrition and Feed Management

A dairy ration is suddenly changed from high roughage to high concentrate. The most likely consequence is:

  1. Increased saliva flow and buffering capacity
  2. Improved rumen pH and increased fibre digestion
  3. Rumen acidosis due to rapid volatile fatty acid accumulation Correct answer.
  4. Reduced risk of laminitis and rumenitis

Explanation

A sudden shift to high concentrate increases rapidly fermentable starch, producing large amounts of volatile fatty acids that lower rumen pH and cause acidosis. This can lead to rumenitis, laminitis and reduced feed intake. Rations should be changed gradually over one to two weeks to allow microbial adaptation.

Question 36Animal Nutrition and Feed Management

The term 'total digestible nutrients' (TDN) is calculated by summing the digestible fractions of which components?

  1. Crude protein and ash only
  2. Crude protein, crude fibre, nitrogen-free extract and ether extract (with fat multiplied by 2.25) Correct answer.
  3. Crude fibre and minerals only
  4. Dry matter and moisture

Explanation

TDN sums the digestible crude protein, crude fibre, nitrogen-free extract and ether extract, with the ether extract multiplied by 2.25 because fat yields about 2.25 times the energy of carbohydrate. It is expressed as a percentage or in kilograms. TDN is an energy measure, so ash and moisture are not included.

Question 37Animal Nutrition and Feed Management

Which feed additive is used to improve feed efficiency and carcass leanness in pigs and poultry but is banned as a growth promoter in many countries due to antimicrobial resistance concerns?

  1. Organic acids
  2. Probiotics
  3. Antibiotic growth promoters Correct answer.
  4. Prebiotics

Explanation

Sub-therapeutic antibiotics were historically used as growth promoters in pig and poultry production, improving feed conversion and reducing disease. Concerns about antimicrobial resistance have led many countries, including the European Union, to ban their routine use. Probiotics, prebiotics and organic acids are alternatives that do not carry the same resistance concern.

Question 38Animal Nutrition and Feed Management

A feedlot steer is fed a ration containing 12% crude protein on a dry matter basis and consumes 10 kg of dry matter daily. What is the daily crude protein intake?

  1. 1.2 kg Correct answer.
  2. 12 kg
  3. 0.12 kg
  4. 120 g

Explanation

Crude protein intake equals dry matter intake multiplied by the protein percentage: 10 kg × 0.12 = 1.2 kg per day. This equals 1,200 g of crude protein. Such calculations help check whether the ration meets the animal's protein requirement for growth.

Question 39Animal Nutrition and Feed Management

In a ruminant, microbial protein synthesized in the rumen is the main source of amino acids because:

  1. Microbial protein replaces the need for all dietary protein
  2. Microbial protein is absorbed directly from the rumen wall
  3. Microbial protein is completely undegradable in the rumen
  4. Microbial protein has a favourable amino acid profile and supplies most of the protein reaching the small intestine Correct answer.

Explanation

Rumen microbes convert nitrogen sources, including non-protein nitrogen, into protein with a good balance of essential amino acids. This microbial protein typically supplies the majority of amino acids flowing to the small intestine in ruminants. Dietary bypass protein supplements it, but does not replace it entirely.

Question 40Animal Nutrition and Feed Management

Which of the following is a characteristic of a good-quality hay?

  1. Presence of mould and heating on storage
  2. Green colour, leafy texture and a pleasant aroma Correct answer.
  3. High proportion of mature stems and seed heads
  4. Brown colour with a musty smell

Explanation

Good hay retains a green colour, has a high leaf-to-stem ratio, and smells fresh and pleasant, indicating that it was cured properly with minimal nutrient loss. Leaves contain most of the protein and energy, so leafiness is an important quality indicator. Mould, brown colour and musty odours indicate poor curing or storage.

Question 41Animal Nutrition and Feed Management

A farmer wants to reduce the risk of nitrate poisoning in cattle grazing a lush cereal crop. The most appropriate management practice is to:

  1. Feed the crop only at midday when nitrate levels peak
  2. Introduce the cattle gradually and avoid grazing heavily fertilised forage after drought or cloudy weather Correct answer.
  3. Allow hungry cattle unrestricted access to the crop
  4. Increase nitrogen fertiliser application before grazing

Explanation

Nitrate accumulates in plants when uptake exceeds conversion to protein, such as after drought, cloudy weather or heavy nitrogen fertilisation. Gradual introduction and avoiding risky periods reduce the dose of nitrate ingested. Hungry animals consume large amounts quickly and are at higher risk of nitrite toxicity.

Question 42Animal Nutrition and Feed Management

Which factor most directly determines the voluntary dry matter intake of a high-producing dairy cow?

  1. The number of feeding times per day only
  2. The brand of mineral supplement used
  3. Body weight, milk yield and the energy density of the ration Correct answer.
  4. The colour of the feed

Explanation

Voluntary dry matter intake in dairy cattle is driven mainly by body weight (rumen capacity), level of milk production and the energy density of the diet. Higher-producing cows need more energy, and they eat more when the ration is more digestible. Feed colour, mineral brand and feeding frequency alone are not primary determinants.

Question 43Animal Nutrition and Feed Management

In feed formulation, a 'least-cost ration' is best described as:

  1. The ration made only from the cheapest single ingredient
  2. A ration that ignores nutrient requirements to minimise cost
  3. The ration with the highest possible protein content
  4. A ration that meets all nutrient requirements at the lowest possible cost using available ingredients Correct answer.

Explanation

Least-cost formulation uses linear programming to select ingredient combinations that satisfy all specified nutrient requirements while minimising total cost. It balances energy, protein, minerals and other constraints rather than simply choosing the cheapest feed. This ensures both nutritional adequacy and economic efficiency.

Question 44Animal Nutrition and Feed Management

Which practice best prevents bloat in cattle grazing legume-rich pasture?

  1. Grazing only the youngest legume growth
  2. Increasing the legume content of the sward
  3. Withholding water during grazing
  4. Feeding roughage before turnout and avoiding grazing lush legumes when hungry Correct answer.

Explanation

Frothy bloat occurs when soluble leaf proteins in lush legumes such as clover stabilise foam in the rumen. Feeding roughage before turnout and avoiding hungry animals on wet, lush pasture reduce the risk. Managing legume proportion and providing poloxalene or other anti-foaming agents are additional measures.

Question 45Animal Breeding, Genetics and Reproduction

In cattle, the structure that serves as the site of fertilization and the primary site of sperm reservoir storage before ovulation is the:

  1. Ampulla of the oviduct Correct answer.
  2. Cranial vagina
  3. Body of the uterus
  4. Cervix

Explanation

The ampullary-isthmic junction of the oviduct is where sperm meet the oocyte and fertilization occurs, and the caudal isthmus acts as the functional sperm reservoir in cattle. The uterus and cervix are transport and gestation structures, not the site of gamete fusion.

Question 46Animal Breeding, Genetics and Reproduction

The normal duration of a bovine estrous cycle (from one estrus to the next) is approximately:

  1. 35 days
  2. 21 days Correct answer.
  3. 48 days
  4. 10 days

Explanation

Cattle are polyestrous with a cycle averaging about 21 days, comprising a follicular phase of roughly 4 days and a luteal phase of about 17 days. Deviations beyond about 18–24 days suggest an abnormality such as cystic ovarian disease or early embryonic loss.

Question 47Animal Breeding, Genetics and Reproduction

The hormone that triggers ovulation in the cow and ewe through a preovulatory surge is:

  1. Oxytocin
  2. Progesterone
  3. Luteinizing hormone Correct answer.
  4. Prolactin

Explanation

A preovulatory surge of luteinizing hormone from the anterior pituitary initiates final follicular maturation, resumption of meiosis and rupture of the follicle. Progesterone and oxytocin do not induce ovulation; progesterone withdrawal merely permits the surge.

Question 48Animal Breeding, Genetics and Reproduction

The sire of a calf is confirmed by parentage testing using DNA markers because each parent contributes:

  1. Only mitochondrial DNA
  2. Two alleles at each locus
  3. Only Y-chromosomal DNA
  4. One allele at each microsatellite or SNP locus Correct answer.

Explanation

Each parent transmits one allele per autosomal locus, so a calf must inherit one of the sire's two alleles at every tested locus. Exclusion of a candidate sire occurs when mismatches appear at multiple loci.

Question 49Animal Breeding, Genetics and Reproduction

In sheep, the practice of 'teasing' with vasectomised rams before the breeding season is used mainly to:

  1. Induce multiple ovulations in rams
  2. Synchronise and stimulate estrus in ewes Correct answer.
  3. Increase lamb birth weight directly
  4. Prevent pregnancy toxaemia in ewes

Explanation

The ram effect works through pheromones and sociosexual stimulation, which advance and tighten the onset of estrus in seasonally anovular ewes. It is a management tool for synchronising mating and tightening the lambing pattern.

Question 50Animal Breeding, Genetics and Reproduction

The primary hormone responsible for maintenance of the corpus luteum and pregnancy in early gestation of ruminants is:

  1. Progesterone Correct answer.
  2. Follicle-stimulating hormone
  3. Prostaglandin F2α
  4. Estradiol-17β

Explanation

Progesterone from the corpus luteum prepares the endometrium and suppresses further ovulations, and its withdrawal causes luteolysis and return to estrus. In cattle the corpus luteum is the sole source of progesterone throughout gestation.