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Maharashtra HSC Animal Husbandry & Dairy (Vocational) study materials
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Maharashtra HSC Animal Husbandry & Dairy (Vocational) practice questions

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Question 1Animal Nutrition and Feeding

In a balanced cattle ration, which nutrient group supplies the largest share of energy to rumen microbes under normal feeding conditions?

  1. Crude fibre
  2. Mineral mixture
  3. Vitamin premix
  4. Carbohydrates Correct answer.

Explanation

Carbohydrates such as starch, sugars and structural polysaccharides are the main energy source fermented by rumen microbes into volatile fatty acids. Fibre is itself a carbohydrate fraction, so it cannot be counted as a separate energy class here. Minerals and vitamins are needed in small amounts and do not supply energy.

Question 2Animal Nutrition and Feeding

Which term describes the total quantity of feed consumed by an animal in 24 hours, expressed on a dry matter basis?

  1. Feed conversion ratio
  2. Nutritive ratio
  3. Digestibility coefficient
  4. Dry matter intake Correct answer.

Explanation

Dry matter intake is the weight of feed eaten after correcting for its moisture content, which allows rations of different moisture to be compared fairly. Digestibility coefficient measures the proportion of a nutrient absorbed, and feed conversion ratio relates feed used to product output. Nutritive ratio compares digestible protein with digestible carbohydrates and fat in the ration.

Question 3Animal Nutrition and Feeding

A dairy farmer notices that a freshly calved cow is off feed and the rumen is distended with gas that cannot be eructated. Which condition should be suspected first?

  1. Bloat Correct answer.
  2. Milk fever
  3. Acidosis
  4. Ketosis

Explanation

Bloat results from excessive gas accumulation in the rumen when eructation fails, commonly after grazing lush legume fodder, and is recognised by a distended left flank and reduced appetite. Ketosis shows nervous signs and a ketone smell, while milk fever presents as recumbency with cold extremities. Acidosis follows sudden grain overload with diarrhoea and low rumen pH rather than gas trapping.

Question 4Animal Nutrition and Feeding

Which roughage is traditionally conserved by sun-drying and is commonly fed to cattle during the scarcity period in Maharashtra?

  1. Silage
  2. Concentrate mixture
  3. Hay Correct answer.
  4. Mineral mixture

Explanation

Hay is conserved fodder made by drying green forage to a safe moisture level so that it stores without spoilage. Silage is preserved by anaerobic fermentation and remains moist, while concentrate and mineral mixtures are supplementary feeds rather than conserved roughages.

Question 5Animal Nutrition and Feeding

Which of the following is classified as a leguminous fodder crop suitable for green feeding to milch animals?

  1. Maize
  2. Jowar
  3. Napier grass
  4. Berseem Correct answer.

Explanation

Berseem is a legume grown as a green fodder and is valued for its high protein content and palatability. Maize, jowar and Napier grass are cereal or grass fodders that are richer in carbohydrates and relatively lower in protein.

Question 6Animal Nutrition and Feeding

Which feed ingredient is the richest plant source of protein among the following and is widely used in concentrate mixtures for dairy cattle?

  1. Maize grain
  2. Rice bran
  3. Molasses
  4. Groundnut cake Correct answer.

Explanation

Groundnut cake is an oilseed meal containing roughly 40 to 45 percent crude protein, making it a standard protein supplement in dairy concentrates. Rice bran, maize grain and molasses are energy-rich feeds with much lower protein content.

Question 7Animal Nutrition and Feeding

A farmer wants to store green fodder for lean months with minimum loss of nutrients. Which conservation method preserves the fodder through anaerobic fermentation?

  1. Hay making
  2. Silage making Correct answer.
  3. Straw stacking
  4. Chaffing

Explanation

Silage making packs chopped green fodder in an airtight pit or silo where lactic acid bacteria ferment sugars into lactic acid, lowering pH and preserving the crop. Hay making relies on drying, and straw stacking or chaffing are not fermentation-based preservation methods.

Question 8Animal Nutrition and Feeding

Which mineral is most commonly deficient in cattle grazing on coarse roughage-based rations and is supplied through common salt in the ration?

  1. Calcium
  2. Sodium and chlorine Correct answer.
  3. Phosphorus
  4. Iron

Explanation

Common salt is added to rations chiefly to supply sodium and chlorine, which are often low in roughage-based diets and are needed for osmotic balance and acid-base regulation. Calcium and phosphorus are supplied mainly through mineral mixtures and bone meal, while iron deficiency is uncommon under normal grazing.

Question 9Animal Nutrition and Feeding

A ration for a growing calf contains 20 percent digestible protein and 60 percent digestible carbohydrates plus fat. What is the nutritive ratio of this ration?

  1. 1:4
  2. 1:3 Correct answer.
  3. 1:1
  4. 1:2

Explanation

Nutritive ratio is calculated as digestible protein to digestible carbohydrates and fat, with fat multiplied by 2.25 because of its higher energy value. Here the ratio is 20 to 60, which simplifies to 1:3, a fairly wide ratio typical of growth rations.

Question 10Animal Nutrition and Feeding

Which statement best explains why urea can replace part of the protein in a cattle ration but not in a poultry ration?

  1. Rumen microbes can convert urea nitrogen into microbial protein, but poultry lack a functional rumen Correct answer.
  2. Urea is toxic to poultry only because of its high phosphorus content
  3. Poultry require more urea than cattle to meet their protein needs
  4. Urea is digested directly by the abomasum in cattle and by the gizzard in poultry

Explanation

Urea supplies non-protein nitrogen that rumen microbes use to synthesise microbial protein, which the animal then digests, so it is useful only in ruminant feeding. Poultry have no functional rumen and cannot convert urea nitrogen into amino acids, and excess urea would be wasted or harmful. Urea contains no phosphorus and is not digested directly in the abomasum or gizzard.

Question 11Animal Nutrition and Feeding

A milch cow yielding 10 litres of milk daily is to be fed a concentrate mixture. Using the thumb rule of 1 kg concentrate for every 2.5 litres of milk, plus 1 kg for maintenance, what quantity of concentrate should be offered per day?

  1. 6 kg
  2. 4 kg
  3. 10 kg
  4. 5 kg Correct answer.

Explanation

The thumb rule gives 10 divided by 2.5, which equals 4 kg for milk production, plus 1 kg for maintenance, totalling 5 kg of concentrate per day. This simple rule helps balance the ration while roughage supplies the remaining nutrients.

Question 12Animal Nutrition and Feeding

Why is gradual introduction of a new concentrate mixture advised when changing the ration of cattle?

  1. To reduce the crude fibre content of the roughage
  2. To allow rumen microbes to adapt and prevent acidosis Correct answer.
  3. To increase the moisture content of the ration
  4. To improve the colour of the concentrate mixture

Explanation

A sudden switch to a concentrate-rich ration favours starch-fermenting bacteria, lowers rumen pH and can cause acidosis and off feed. Gradual introduction over about a week allows the microbial population to adjust and keeps rumen fermentation stable. Moisture, fibre content of roughage and colour are unrelated to the adaptation process.

Question 13Animal Nutrition and Feeding

In a proximate analysis report, a feed sample shows 90 percent dry matter, 20 percent crude protein and 4 percent ether extract. Which fraction represents nitrogen-free extract?

  1. Approximately 54 percent Correct answer.
  2. Approximately 66 percent
  3. Approximately 70 percent
  4. Approximately 46 percent

Explanation

Nitrogen-free extract is obtained by subtracting crude protein, ether extract, crude fibre and ash from the dry matter, so the crude fibre and ash values must be known. With the figures given, only about 54 percent remains once typical fibre and ash values are accounted for, which fits the nitrogen-free extract fraction. The other values either ignore fibre and ash or miscalculate the subtraction.

Question 14Animal Nutrition and Feeding

Which practice best reduces wastage and improves utilisation when feeding dry paddy straw to cattle?

  1. Feeding the whole straw in long bundles
  2. Mixing the straw with soil
  3. Chaffing and soaking the straw before feeding Correct answer.
  4. Feeding the straw dry along with excess water

Explanation

Chaffing shortens the straw so animals sort less and waste less, while soaking improves palatability and intake of dry roughage. Feeding long bundles or mixing with soil increases refusal and contamination, and excess water alone does not improve utilisation.

Question 15Animal Nutrition and Feeding

Which of the following best describes the role of bypass protein in the nutrition of high-yielding dairy cows?

  1. It escapes rumen degradation and supplies amino acids in the small intestine Correct answer.
  2. It supplies non-protein nitrogen for microbial growth
  3. It acts as a buffer against rumen acidity
  4. It is fermented rapidly in the rumen to supply energy

Explanation

Bypass or rumen-undegradable protein passes through the rumen without being broken down and is digested in the abomasum and small intestine, supplying amino acids directly to high-producing animals. Rapidly fermented feeds supply energy rather than bypass protein, non-protein nitrogen is a different category, and buffers such as sodium bicarbonate control acidity.

Question 16Animal Nutrition and Feeding

A farmer feeding a high-grain ration notices frothy rumen contents and persistent bloat in several animals. Which management change is most appropriate?

  1. Feed only finely ground concentrate without roughage
  2. Reduce grain level and include adequate long roughage in the ration Correct answer.
  3. Increase the grain level to stimulate rumen microbes
  4. Withdraw drinking water for the whole day

Explanation

Frothy bloat on high-grain rations reflects an imbalance between rapidly fermentable starch and the fibre needed for rumination and saliva flow. Reducing grain and restoring long roughage helps normal rumen function and gas expulsion. More grain, water restriction or all-concentrate feeding would worsen the condition.

Question 17Animal Nutrition and Feeding

Which statement about the water requirement of a lactating cow is most accurate?

  1. Water need is unrelated to milk yield
  2. Water need is highest in dry animals
  3. Water need rises with milk yield because milk is about 87 percent water Correct answer.
  4. Water need equals the dry matter intake in kilograms

Explanation

Milk contains roughly 87 percent water, so a high-yielding cow needs substantially more drinking water than a dry animal. Water requirement generally increases with dry matter intake and milk production, so the other statements misrepresent the relationship.

Question 18Animal Nutrition and Feeding

Which of the following is the main objective of adding a mineral mixture to the concentrate ration of dairy cattle?

  1. To improve the energy value of the concentrate
  2. To correct deficiencies of calcium, phosphorus and trace elements Correct answer.
  3. To increase the crude protein content of the ration
  4. To preserve the concentrate mixture during storage

Explanation

Mineral mixtures are formulated to supply calcium, phosphorus, salt and trace elements that are often deficient in roughage-based rations. They contribute negligible protein or energy and are not preservatives, so they are added purely for mineral nutrition.

Question 19Animal Nutrition and Feeding

A farmer has 100 kg of green fodder containing 80 percent moisture. What is the approximate dry matter content of this fodder?

  1. 80 kg
  2. 100 kg
  3. 10 kg
  4. 20 kg Correct answer.

Explanation

Dry matter is the portion remaining after moisture is removed, so 100 kg multiplied by 20 percent dry matter equals 20 kg. The 80 kg figure is the moisture content, not the dry matter, and the other values do not follow from the calculation.

Question 20Animal Nutrition and Feeding

Which feed additive is used to improve fibre digestion in cattle fed poor-quality roughage by supplying a specific enzyme or microbial culture?

  1. Molasses
  2. Common salt
  3. Urea
  4. Yeast culture Correct answer.

Explanation

Yeast culture is a feed additive that supports fibre-digesting bacteria and stabilises rumen pH, improving fibre digestion in animals on poor roughage. Urea supplies non-protein nitrogen, common salt supplies sodium and chlorine, and molasses is an energy source, so none of these is a microbial feed additive.

Question 21Animal Nutrition and Feeding

Which consideration is most important when deciding the particle length of silage or hay for dairy cattle?

  1. Uniform length equal to the size of the feed trough
  2. Shortest possible length to reduce chewing time
  3. Adequate effective fibre length to maintain rumination and rumen pH Correct answer.
  4. Maximum fineness to increase bulk density in the silo

Explanation

Effective fibre of adequate length stimulates chewing, saliva secretion and rumination, which help maintain rumen pH and prevent acidosis. Excessive fineness or very short particles reduce chewing and rumination, while trough size is irrelevant to particle length.

Question 22Animal Nutrition and Feeding

A feed sample contains 90 percent dry matter and 12 percent crude protein on a dry matter basis. What is the crude protein content on an as-fed basis?

  1. 13.3 percent
  2. 12 percent
  3. 9 percent
  4. 10.8 percent Correct answer.

Explanation

To convert from a dry matter basis to an as-fed basis, multiply by the dry matter fraction, so 12 percent multiplied by 0.90 equals 10.8 percent. The value 12 percent is the dry matter basis, while dividing by 0.90 gives 13.3 percent, which is the reverse conversion.

Question 23Animal Nutrition and Feeding

Which feeding strategy is most appropriate for a calf during the first week of life to ensure adequate intake of colostrum?

  1. Wait 24 hours before the first feed to allow the calf to settle
  2. Feed diluted milk replacer instead of colostrum
  3. Feed only water and hay for the first two days
  4. Feed colostrum within the first hour or two after birth at about 10 percent of body weight Correct answer.

Explanation

Colostrum must be fed soon after birth because the intestine can absorb maternal antibodies only during a short window and antibody concentration in colostrum declines rapidly. Feeding about 10 percent of body weight gives adequate volume for passive immunity. Delay, replacement with milk replacer or feeding only water and hay leaves the calf unprotected.

Question 24Animal Nutrition and Feeding

A farmer wants to formulate a concentrate mixture with 20 percent crude protein using maize (9 percent CP) and groundnut cake (45 percent CP). Using the Pearson square method, what proportion of groundnut cake is required?

  1. Approximately 45 percent
  2. Approximately 69 percent
  3. Approximately 20 percent
  4. Approximately 31 percent Correct answer.

Explanation

In the Pearson square, the differences between the target and each ingredient are taken diagonally: 45 minus 20 equals 25 parts maize and 20 minus 9 equals 11 parts groundnut cake. The cake share is 11 out of 36 parts, which is about 31 percent. The other figures represent either the ingredient's own protein content or the maize share.

Question 25Animal Nutrition and Feeding

Which statement correctly explains why excessive urea feeding can cause toxicity in cattle?

  1. Urea is converted to fat in the rumen and causes obesity
  2. Urea binds calcium in the blood and causes milk fever
  3. Rapid release of ammonia exceeds the liver's capacity to convert it to urea, raising blood ammonia Correct answer.
  4. Urea directly damages the rumen wall by abrasion

Explanation

When urea is consumed too quickly or in excess, rumen microbes release ammonia faster than the liver can convert it to urea for excretion, so blood ammonia rises and signs of toxicity such as tremors and bloat appear. Urea does not abrade the rumen, bind calcium to cause milk fever, or turn into fat in the rumen.

Question 26Animal Nutrition and Feeding

In a concentrate mixture for dairy cattle, which ingredient is included mainly to supply energy while also improving palatability and binding the mash?

  1. Molasses Correct answer.
  2. Groundnut cake
  3. Common salt
  4. Bone meal

Explanation

Molasses is a by-product of sugar manufacture rich in soluble sugars, so it supplies readily available energy and also sweetens the mash and reduces dustiness. Protein cakes, mineral supplements and salt serve different roles in the mixture.

Question 27Animal Nutrition and Feeding

A dairy farmer in a drought-hit area has limited green fodder but plenty of dry maize stover. Which practice best improves the feeding value of this stover for maintenance of dry cows?

  1. Boiling the stover for several hours before feeding
  2. Chaffing and soaking it with water plus a small quantity of molasses and urea Correct answer.
  3. Feeding it alone as the sole roughage without any supplement
  4. Feeding it whole and unchopped to slow intake

Explanation

Chaffing reduces wastage and soaking with molasses and a little urea softens the stover, raises its nitrogen content and improves rumen microbial fermentation of the fibre. Whole, unsupplemented or boiled stover remains poorly digestible and wasteful.

Question 28Animal Nutrition and Feeding

Which statement correctly describes the concept of total digestible nutrients (TDN) as used in evaluating cattle feeds?

  1. It is the mineral matter left after complete ignition of the feed sample
  2. It is the sum of digestible protein, digestible carbohydrate and 2.25 times the digestible fat Correct answer.
  3. It is the sum of digestible crude fibre and digestible ash expressed as a percentage
  4. It is the total crude protein content of the feed measured after nitrogen estimation

Explanation

TDN expresses the energy value of a feed by adding digestible crude protein, digestible nitrogen-free extract, digestible crude fibre and digestible fat multiplied by 2.25 because fat yields about 2.25 times the energy of carbohydrate. It is an energy measure, not a protein or mineral measure.

Question 29Animal Nutrition and Feeding

A crossbred cow in early lactation is fed a ration very low in fibre with a large amount of finely ground concentrate. Which consequence is most consistent with rumen function?

  1. Reduced rumen pH with depressed fibre digestion and milk fat Correct answer.
  2. Faster rumen microbial protein synthesis with no risk of acidosis
  3. Enhanced acetate production and higher milk fat percentage
  4. Increased chewing and greater saliva flow into the rumen

Explanation

A low-fibre, high-concentrate ration is fermented rapidly, producing large amounts of volatile fatty acids and less saliva for buffering, so rumen pH falls. At low pH the fibre-digesting bacteria are inhibited, the acetate to propionate ratio drops and milk fat percentage declines.

Question 30Animal Nutrition and Feeding

Which mineral mixture component is added to cattle rations chiefly to prevent white muscle disease and to support antioxidant function along with vitamin E?

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

Explanation

Selenium works together with vitamin E as an antioxidant and its deficiency in calves and lambs causes white muscle disease. Iodine, copper and manganese have other specific roles and do not jointly act with vitamin E in this way.

Question 31Animal Breeding and Genetics

In dairy cattle breeding, which term describes the proportion of the total phenotypic variation in a herd that is due to additive genetic differences among animals?

  1. Selection differential
  2. Heritability Correct answer.
  3. Heterosis
  4. Repeatability

Explanation

Heritability expresses the share of observed phenotypic variance attributable to additive genetic variance, so it predicts how strongly a trait responds to selection. It is a property of a trait within a specific population and environment, not a fixed constant of the breed.

Question 32Animal Breeding and Genetics

A Murrah buffalo breeder wants the fastest possible genetic gain in first-lactation milk yield. Which breeding strategy is most appropriate for this herd?

  1. Progeny testing of bulls followed by AI with the top sires Correct answer.
  2. Crossing with a beef breed to increase body weight
  3. Grading up the herd with a single local bull for many years
  4. Random mating within the herd without record keeping

Explanation

Milk yield is a sex-limited trait with moderate heritability, so genetic gain depends on accurate sire evaluation through progeny testing and wide use of proven bulls via artificial insemination. This increases selection intensity and shortens the generation interval compared with keeping a single herd bull.

Question 33Animal Breeding and Genetics

The Sahiwal breed of cattle is best described by which combination of characteristics?

  1. Exotic Bos taurus dairy type with black-and-white coat and high milk yield
  2. Zebu dairy type, red-brown coat, high heat tolerance, native to the Indian subcontinent Correct answer.
  3. Buffalo breed with curled horns kept mainly for milk in the Punjab
  4. Dual-purpose hill breed with a prominent hump and long horns used for draught only

Explanation

Sahiwal is an indigenous Bos indicus dairy breed, typically red-brown, tick- and heat-tolerant, and well suited to tropical conditions. It is valued in crossbreeding programmes for its adaptability and milk quality.

Question 34Animal Breeding and Genetics

Two crossbred heifers are produced from the same Jersey bull and the same Holstein Friesian dam line. Which statement about their expected genetic merit for milk yield is most accurate?

  1. Their breeding values will differ only because of the sex of the calf
  2. Their phenotypes will be similar but their breeding values will be completely unrelated
  3. Their breeding values will be similar but their phenotypes may differ because of environmental and non-additive effects Correct answer.
  4. Their breeding values will be identical and their milk yields will be identical

Explanation

Breeding value reflects the additive gene effects transmitted to offspring, so full sibs share an expected breeding value but differ in realised merit because of Mendelian sampling, non-additive gene action and environmental effects. Phenotype is the sum of genotype and environment, so identical phenotypes are not expected.

Question 35Animal Breeding and Genetics

Which mating system is being used when a breeder crosses two purebred lines and then mates the resulting crossbred females to a third pure breed?

  1. Three-breed rotational crossing Correct answer.
  2. Two-breed terminal cross
  3. Grading up
  4. Inbreeding

Explanation

Using crossbred females from two breeds and mating them to a third breed is the defining structure of three-breed rotational crossing, which exploits both maternal and individual heterosis. Grading up and inbreeding involve a single breed, and a terminal cross does not retain crossbred females for breeding.

Question 36Animal Breeding and Genetics

In a herd, the average milk yield is 3000 kg and the selected parents average 3600 kg. If heritability of milk yield is 0.25, what is the expected response to selection in the next generation?

  1. 75 kg
  2. 150 kg Correct answer.
  3. 2400 kg
  4. 600 kg

Explanation

Response equals heritability multiplied by the selection differential, so 0.25 × (3600 − 3000) = 150 kg. The selection differential of 600 kg is the phenotypic superiority of the parents, and only the heritable fraction appears as gain.

Question 37Animal Breeding and Genetics

Which of the following is an example of a simply inherited (qualitative) trait in farm animals?

  1. Egg weight in poultry
  2. Body weight at six months in goats
  3. Coat colour in cattle Correct answer.
  4. Milk yield in buffaloes

Explanation

Coat colour is controlled by one or a few gene loci with discrete phenotypes, so it is a qualitative trait. Milk yield, body weight and egg weight are continuous traits influenced by many genes plus environment.

Question 38Animal Breeding and Genetics

A purebred Holstein Friesian cow is mated to a purebred Jersey bull. The F1 female offspring is then mated back to a purebred Holstein Friesian bull. What proportion of Holstein Friesian inheritance is expected in the resulting calf?

  1. 100 per cent
  2. 25 per cent
  3. 75 per cent Correct answer.
  4. 50 per cent

Explanation

The F1 female carries 50 per cent Holstein Friesian inheritance, and her calf receives half of that (25 per cent) from her plus 50 per cent from the pure Holstein Friesian sire, giving 75 per cent. This is the standard arithmetic of grading up.

Question 39Animal Breeding and Genetics

Which breeding method is most suitable for improving a trait with high heritability, such as butterfat percentage, in a small herd where progeny testing is not feasible?

  1. Individual selection based on the animal's own record Correct answer.
  2. Random mating
  3. Family selection using only half-sib records
  4. Progeny testing of young bulls

Explanation

When heritability is high, an animal's own phenotype is a good predictor of its breeding value, so individual (mass) selection gives rapid progress and needs no progeny data. Progeny testing is costly and slow and is justified mainly for lowly heritable, sex-limited traits.

Question 40Animal Breeding and Genetics

Inbreeding in a closed cattle herd is most likely to produce which consequence?

  1. Increased heterozygosity and hybrid vigour
  2. Increased homozygosity and inbreeding depression in fitness traits Correct answer.
  3. A rise in the frequency of recessive alleles in the gene pool
  4. Immediate fixation of favourable dominant alleles

Explanation

Inbreeding raises the probability that an animal carries two copies of alleles identical by descent, increasing homozygosity and exposing deleterious recessives, which lowers fertility and viability. Allele frequencies in the population do not change; only the genotypic proportions shift.

Question 41Animal Breeding and Genetics

Which of the following correctly states a difference between artificial insemination and natural service in cattle breeding?

  1. Artificial insemination eliminates the risk of venereal infection entirely
  2. Artificial insemination removes the need for accurate heat detection
  3. Artificial insemination allows one bull to sire far more offspring in a year than natural service Correct answer.
  4. Artificial insemination cannot be used with frozen semen

Explanation

A single ejaculate can be diluted into many doses of semen, so AI greatly multiplies the number of cows a superior bull can serve and accelerates genetic gain. It does not remove the need for heat detection and requires strict hygiene to control infection.

Question 42Animal Breeding and Genetics

A buffalo breeder records that daughters of bull A average 2100 kg milk while daughters of bull B average 1950 kg, though both bulls had similar dam-side pedigrees. Which conclusion is best supported?

  1. The difference is due to heterosis and cannot be inherited
  2. Both bulls have equal breeding value because the difference is small
  3. Bull B is genetically superior because pedigree is the only reliable guide
  4. Bull A has a higher estimated breeding value for milk yield and should be preferred Correct answer.

Explanation

Progeny performance is the strongest evidence of a sire's transmitting ability, so the bull whose daughters yield more has the higher estimated breeding value when daughters are managed comparably. Pedigree information is useful before progeny data exist but is less accurate.

Question 43Animal Breeding and Genetics

The main purpose of maintaining a pedigree record in a dairy herd is to:

  1. Trace ancestry and calculate relationship and inbreeding coefficients Correct answer.
  2. Record daily milk yield for the lactation curve
  3. Maintain the feed and fodder inventory
  4. Note the dates of vaccination and deworming

Explanation

A pedigree documents parentage across generations, which is essential for computing coefficients of relationship and inbreeding and for planning matings. Production, health and feed records serve different management purposes.

Question 44Animal Breeding and Genetics

Which statement about heterosis is correct?

  1. It is greatest for traits with high heritability and accumulates across generations
  2. It is greatest for traits with low heritability and is not transmitted to the next generation Correct answer.
  3. It is permanent once a crossbred line is formed
  4. It is caused by the additive effects of genes alone

Explanation

Heterosis arises from non-additive gene action such as dominance and epistasis, so it is largest for fitness and reproductive traits with low heritability and is lost when crossbreds are inter se mated. The additive component, by contrast, is transmitted and responds to selection.

Question 45Animal Breeding and Genetics

A goat herd shows a trait with phenotypic variance of 40 units and additive genetic variance of 10 units. What is the heritability of the trait in this herd?

  1. 0.25 Correct answer.
  2. 0.40
  3. 4.0
  4. 0.75

Explanation

Heritability in the narrow sense is the ratio of additive genetic variance to phenotypic variance, so 10/40 = 0.25. The value applies to this herd and environment and would change with different conditions.

Question 46Animal Breeding and Genetics

Which of the following best describes the role of a nucleus breeding herd in a dairy cattle breeding programme?

  1. It is a quarantine station for imported animals
  2. It produces genetically superior bulls and semen for distribution to commercial herds Correct answer.
  3. It receives surplus calves from commercial farms for fattening
  4. It supplies only frozen semen to other countries

Explanation

A nucleus herd is the elite tier where selection intensity is highest and superior sires are generated and tested for wider use. Commercial herds form the lower tiers that receive genetic material from the nucleus.

Question 47Animal Breeding and Genetics

In a crossbreeding programme for market goat production, which type of heterosis is exploited when crossbred does are used as mothers and their kids are sold?

  1. Heterosis only in the terminal sire
  2. Paternal heterosis only
  3. Maternal heterosis in the doe plus individual heterosis in the kid Correct answer.
  4. No heterosis because the does are crossbred

Explanation

A crossbred doe benefits from maternal heterosis in fertility and mothering ability, while her crossbred kid benefits from individual heterosis in growth and survival. Both effects contribute to output in a terminal cross.

Question 48Animal Breeding and Genetics

Which of the following is an example of a chromosomal sex-determination abnormality that can affect breeding efficiency in cattle?

  1. Mastitis caused by bacterial infection
  2. Rickets caused by vitamin D deficiency
  3. Bloat caused by legume-rich fodder
  4. Freemartin condition in the female co-twin of a bull calf Correct answer.

Explanation

A freemartin is a genetically female calf that shares the uterus with a male twin and is masculinised by hormonal exchange, resulting in an infertile heifer. Rickets, mastitis and bloat are nutritional or infectious conditions, not chromosomal sex abnormalities.

Question 49Animal Breeding and Genetics

A breeder wishes to estimate the repeatability of lactation yield in a buffalo herd. Which interpretation of a high repeatability value is correct?

  1. The trait is strongly inherited and will respond rapidly to selection
  2. The trait is unaffected by permanent environmental factors
  3. The first lactation record is a reliable guide to later lactations of the same animal Correct answer.
  4. The herd average will shift quickly under selection

Explanation

Repeatability measures the consistency of repeated records on the same animal and therefore indicates how well an early record predicts later ones. It includes both genetic and permanent environmental variance, so it is not a measure of heritability or of selection response.

Question 50Animal Breeding and Genetics

Which of the following is the correct description of the term 'progeny testing' in dairy cattle breeding?

  1. Evaluating a cow's breeding value from her own milk record
  2. Evaluating a sire's breeding value from the performance of his daughters Correct answer.
  3. Testing the fertility of a bull by observing libido
  4. Testing the milk quality of a herd before sale

Explanation

Progeny testing estimates a sire's transmitting ability from the records of his daughters compared with herd contemporaries. It is especially valuable for sex-limited traits such as milk yield that cannot be measured in the bull himself.