Conformation, Body Composition, and Meat Quality | Animal Husbandry & Veterinary Science Optional for UPSC PDF Download

Conformation

Changes in Body Proportions

• When animals grow, their body proportions change significantly.
• Calves have larger heads, necks, and legs, making low-priced body parts like the underside, lower limbs, and neck prominent.

Impact of Growth on Value

• The rate and extent of changes in body shape affect the animal's value for beef.
• The back grows faster than low-priced joints, influencing the overall meat quality.

Gender Differences

• Males show greater lengthening, deepening, and muscle development than females or castrated animals.
• Males also exhibit more developed heads and necks.

Nutrition Influence

• The animal's diet affects body proportions and value.
• Early developing parts are less affected by nutrition than later developing ones.

Breeding for Beef

• Beef breeds are developed for depth of fleshing, rapid growth, and fat deposition between muscles.
• Improvements include shortening bones and thickening muscles, resulting in a blocky joint appearance.

Market Trends

• Earlier, the focus was on early maturation and blocky joints with fat.
• Now, rapid growth and lean meat production are more important.

Body Composition

Meat's Importance

• Meat is crucial in the human diet for its concentrated and easily digestible protein.
• It stimulates metabolism, delays stomach emptying, and satisfies hunger.

Comparison with Vegetable Diet

• Meat provides essential amino acids not found in a vegetable diet.
• Vegetable proteins are easier to digest but lead to quicker hunger recurrence.

Meat Components

• Lean bovine muscle composition includes water (75%), protein (19%), lipids (fats and oils, 25%), and carbohydrates (glycogen, 12%).

Protein

• Main muscle component, contributing to rigidity.
• Comprises myofibrillar, sarcoplasmic, and connective tissue proteins.
• Myofibrillar proteins include actin and myosin.
• Sarcoplasmic proteins are water-soluble and include myoglobin and enzymes.
• Connective tissue proteins support the muscle structure along with bony segments.

Meat Quality

Composition Overview:

• Meat is valuable for its protein content, aiding in heat and energy production.
• Fat in meat delays stomach emptying, providing a satisfying feeling.
• Proper treatment enhances flavor, stimulates gastric secretion, and ensures easy digestion.

Role of Meat in Diet

• Meat contributes essential nutrients, amino acids, and vitamins to the diet.
• It offers a palatable flavor, acts as a gastric stimulant, and is readily digestible.

Offal Consideration

• The term "meat" can also include edible offal like liver, heart, and tongue.
• These are not part of the skeletal-muscular system but are still valuable components.

Proteins:

• Found in meat, including collagen, elastin, and reticulin.
• Collagen turns into gelatin when heated, while elastin and reticulin remain tough connective tissues.

Lipids (Fats)

• Mainly triglycerides (fats and oils) present.
• Insoluble in water but soluble in ether.
• Also includes phospholipids, fatty acids, and other fat-soluble substances.
• Varies in quantity among meat animals; horses have high fat content, cattle more than sheep, and pigs the least.
• Fat content has decreased due to cost and consumer preferences.

Carbohydrates

• Mainly represented by glycogen (animal starch).
• Influences muscle changes after death; converted to lactic acid, affecting meat pH.
• Low glycogen levels result in higher pH, while high levels lead to lower pH.
• pH influences water-holding capacity, color development, and bacterial growth in meat.

Non-Protein Nitrogen

• Includes free amino acids, creatine, nucleotides, inosine monophosphate, and carnosine.
• Contributes to the flavor of meat on cooking.
• Flavor production is complex; influenced by factors like age, exercise, and rest prior to slaughter.
• Breed and sex can affect flavor, especially in pigs.

Flavor in Meat

• Derived from sugars, lipids, nitrogen-containing compounds, and oxygen/sulfur-containing compounds.
• Influenced by factors like age, exercise, and rest prior to slaughter.
• Fully-grown animals and well-rested animals produce better flavor.
• Breed has minimal impact on flavor, but sex, especially in pigs, can affect taste.
• Slaughtering at younger ages may reduce the impact of sex on flavor.
• Recent studies show little correlation between nutrition level and flavor, challenging the belief that fatness guarantees good taste and tenderness.

Meat Extracts

• Extractives are key components in commercial meat extracts, obtained by concentrating liquids from cooked beef muscle or offal.
• About 13.6 kg of lean meat produces 453 g of extract.
• Although not highly nutritious, extractives stimulate gastric juice flow and aid in food digestion.

Minerals

• Inorganic minerals in meat make up less than 1%, including sulfur, potassium, phosphorus, sodium, chlorine, magnesium, calcium, iron, and zinc.

Vitamins

• Meat contains water-soluble B vitamins (B1, B2, niacin, B6, pantothenic acid, biotin, folic acid, B12), vitamin A, and vitamin C.
• Pork has more thiamine than beef, while beef has more folate. Cooking reduces vitamin levels.

Other Meat Components

• Myoglobin and hemoglobin are important pigments in meat, with myoglobin contributing to redness.
• Enzyme actions and oxidizing agents affect meat color, especially in conditions like icterus.
• Meat quality changes after death, becoming darker and stickier initially, then lighter and wetter.

Rigor Mortis

• Rigor mortis is the first significant post-mortem change, causing muscle hardening and contraction.
• It starts in active, well-nourished muscles, affecting the head and neck first and gradually spreading.
• Rigor mortis peaks between 20-24 hours post-mortem and then fades.

Tenderization of Meat

• Storing meat at low temperatures (0-3°C) slows down changes that occur at higher temperatures.
• Conditioning or ripening occurs, enhancing flavor, juiciness, and tenderness.
• Tenderness is influenced by factors like breed, age, nutrition, and muscle exercise.
• Rigor mortis initially makes meat tough but then it becomes tender as it passes off.
• Softening of collagen fibers and conversion to gelatin by lactic acid also contribute to tenderness.
• Feeding influences the color and texture of meat, with grass-fed animals having rich yellow fat.

Odor and Taints

• Meat can acquire odors from external sources like feed or drugs, or intrinsic odors like those from specific health conditions.