Animal Digestive Systems, Nutrients, and Dairy Breeds Overview

What animals do NOT have gallbladders?

Horses, deer, rats, camels.

List each part of a monogastric digestive system (in order).

Mouth → Esophagus → Stomach → Duodenum → Jejunum → Ileum → Cecum → Colon → Rectum → Anus.

Where does fiber breakdown occur in horses and why?

In the cecum and large colon due to microbial fermentation (hindgut fermentation).

What are the accessory organs? What does each one do?

Liver: produces bile; Gallbladder: stores bile (not in horses); Pancreas: secretes enzymes & insulin; Salivary glands: moisten food & begin digestion.

Beak (avian digestive tract function)

Picks up and breaks food.

Esophagus (avian digestive tract function)

Moves food to crop.

Crop (avian digestive tract function)

Temporary food storage.

Proventriculus (avian digestive tract function)

"True stomach"; secretes acid and enzymes.

Gizzard (avian digestive tract function)

Grinds food with grit.

Small intestines (avian digestive tract function)

Nutrient absorption (duodenum, jejunum, ileum).

Ceca (avian digestive tract function)

Two pouches; ferment undigested fiber.

Large intestines (avian digestive tract function)

Absorbs water and salts.

Cloaca (avian digestive tract function)

Common exit for digestive, urinary, and reproductive tracts.

Vent (avian digestive tract function)

External opening for waste and eggs.

Do chickens have two ceca?

Yes.

Examples of ruminants

Cows, sheep, goats, deer, bison.

Animals that only have bottom incisors (examples)

Ruminants like cows, sheep, goats.

Rumen (function)

Fermentation vat; microbes digest fiber.

Reticulum (function)

Honeycomb structure; traps foreign objects, mixes digesta.

Omasum (function)

Absorbs water and nutrients.

Abomasum (function)

True stomach; secretes acid and enzymes.

Six essential nutrients

Water, Carbohydrates, Fats, Proteins, Vitamins, Minerals.

Cheapest essential nutrient

Water.

"PVT TIM HALL" amino acids

Phenylalanine, Valine, Threonine, Tryptophan, Isoleucine, Methionine, Histidine, Arginine, Leucine, Lysine.

Essential amino acid in cats for retinal health

Taurine.

Two essential amino acids for poultry

Glycine and Proline.

Crude protein if feed has 12% nitrogen

12 × 6.25 = 75% crude protein.

ADF (Acid Detergent Fiber)

Cellulose + lignin (least digestible portion).

NDF (Neutral Detergent Fiber)

Hemicellulose + cellulose + lignin.

NDSC (Non-Detergent Soluble Carbohydrates)

Sugars and starches.

NDSF (Non-Detergent Soluble Fiber)

Pectin, beta-glucans.

Least digestible carbohydrate composition

ADF.

Which is more energy-dense: fats or carbohydrates? By how much?

Fats, about 2.25 times more energy than carbohydrates.

Difference between saturated and unsaturated fatty acids

Saturated: no double bonds; solid at room temp. Unsaturated: one or more double bonds; liquid at room temp.

Minerals required for skeletal formation

Calcium (Ca), Phosphorus (P), Magnesium (Mg).

Minerals required for oxygen transport

Iron (Fe), Copper (Cu).

Minerals required for fluid and acid-base balance

Sodium (Na), Potassium (K), Chloride (Cl).

Why are vitamins essential?

Regulate metabolism, support growth, reproduction, and immune function.

Holstein breed description

Black and white; highest milk yield.

Guernsey breed description

Golden milk high in beta-carotene.

Jersey breed description

Small size; highest milk fat percentage.

Brown Swiss breed description

Large, strong; milk high in protein.

Ayrshire breed description

Hardy, red and white, good grazer.

Jamaican Hope breed description

Heat-tolerant tropical dairy breed.

Milking Shorthorn breed description

Dual-purpose (milk and meat).

Dutch Belt breed description

Black with white belt; moderate production.

Purpose of the dairy industry

Produce milk and dairy products for human consumption.

What did Egypt produce?

Cheese and cultured dairy products.

Land Grant Act purpose

Established agricultural colleges for research and education.

Hatch Act purpose

Created agricultural experiment stations.

Babcock Test purpose

Measures butterfat content in milk.

Process using heat to kill harmful microorganisms in milk

Pasteurization.

What is homogenization?

Process that breaks fat globules so milk stays uniform.

Top states in dairy cattle numbers

California, Wisconsin, Idaho, Texas, New York.

California Dairy Statistics

#1 dairy state; produces ~18-20% of U.S. milk; ~1.7 million cows.

Solutions to environmental concerns in dairy industry

Manure management, methane digesters, efficient water use, feed additives to reduce emissions.

Sources of income in the dairy industry

Milk sales, calves, cull cows, manure byproducts.

What are newborn calves fed and why?

Colostrum; contains antibodies for immunity.

What is used on a calf's navel and why?

Iodine; disinfects and prevents infection.

Breeding weights for dairy breeds

Holstein: 750-800 lbs; Jersey: 600-650 lbs; others 700-800 lbs.

What is a springer?

A cow or heifer close to calving.

What is a dry cow?

A cow not producing milk (rest period before calving).

What is given to springers and dry cows for good BCS?

Forages and balanced minerals.

Advantages of artificial insemination (AI)

Genetic improvement, disease control, cost-effective, safer.

Gestation period of a dairy cow

283 days (~9 months).

Prolactin (LTH) function

Stimulates milk production.

Oxytocin function

Causes milk letdown and uterine contractions.

Epinephrine function

Inhibits milk letdown (stress hormone).

Steps in the milking procedure

Wash and dry udder → Forestrip → Attach milking unit → Detach and post-dip teats.

Common pathogens for mastitis

Staphylococcus aureus, Streptococcus agalactiae, E. coli.

What is ketosis, treatment, and breath smell?

Energy deficit; treat with propylene glycol; breath smells like acetone.

What is milk fever?

Calcium deficiency (hypocalcemia) after calving.

What is hardware disease and how treated?

Ingested metal punctures stomach; treated with a magnet in reticulum.

What is white muscle disease?

Selenium and Vitamin E deficiency.

How do you treat bloat?

Use a trocar, tubing, or anti-foaming agents.

Reasons to cull a cow (top reason)

Low milk production (top), reproductive failure, mastitis, lameness.

Which part of the cow counts most in judging?

Udder (highest % of score).

What is BST and why was it used?

Bovine Somatotropin; hormone that increases milk yield (no longer commonly used).