ANSC EXAM 2

1. Health & Welfare: The "Stress" Connection

  • Production Logic: Animals in constant stress or suffering cannot produce efficiently.

  • Clinical vs. Subclinical:

    • Clinical: Visible signs such as limping, fever, cough.

    • Subclinical: No visible signs; these are "hidden" carriers that require lab tests to identify.

  • Pathogen 4-Step Cycle:

    1. Enter body

    2. Adapt/Reproduce

    3. Exit body

    4. Attack new host.

  • Terminology:

    • Etiology is the term used to describe the cause of a disease.

    • Pathology is the study of the nature of the disease.

  • Immunity:

    • Passive Immunity:

    • Antibodies are "gifted" through colostrum or first milk.

    • Provides short-term protection.

    • Active Immunity:

    • Antibodies are "earned" through the animal's immune system response to vaccinations or past infections.

2. Environmental Physiology & Temperatures

[!important]
SPECIES BODY TEMPERATURES (Memorize these!):

  • 100.0°F: Horse (The "Coolest")

  • 101.5°F: Cattle and Cats

  • 102.0°F: Sheep, Goats, Pigs, and Dogs (The "Warmest")

  • Thermal Neutral Zone (TNZ):

    • Defined as the range where production efficiency is maximized, meaning that zero energy is expended on cooling or warming.

  • Heat Stress (UCT):

    • Under conditions of heat stress, feed intake decreases while water intake increases by 50–100%.

  • Cold Stress (LCT):

    • Under cold stress, feed intake increases as animals need more energy to generate body heat.

  • Cooling Methods:

    • Shade: Considered the cheapest solution.

    • Evaporative cooling: Most effective for swine; utilizes water to cool the animals.

    • Refrigeration: Generally too expensive for widespread use.

3. Grading Math: Beef Yield Grades




  • Base Yield Grade = 2.0



  • Factors and Calculation Rules:


    Factor

    Calculation Rule



    Hot Carcass Wt (HCW)

    Base = 600 lbs. Add/Subtract 0.4 for every 100 lbs over/under.



    Fat Thickness

    Add 0.25 for every 0.1 inch of fat.



    Ribeye Area (REA)

    Base = 11.0. SUBTRACT 0.33 for every 1.0 inch larger than base.



    KPH Fat

    Base = 3.5%. Add 0.2 for every 1% over.





    [!tip]
    Yield Grade Hint: A lower number (for example, 1 or 2) signifies a "better" yield because it indicates more lean muscle and less fat. Larger muscle size means to subtract from the overall score.



    4. Quality Grading & Meat Safety

    • Beef Quality Factors:

      • Determined by Maturity (age of the animal) and Marbling (amount of intramuscular fat).

    • Maturity Classes:

      • Maturity A: 9–30 months; eligible for Premium cuts such as Prime and Choice.

      • Maturity C+: 42 months or older; usually grades as Commercial, utilized for ground beef or utility.

    • Sheep Grading:

      • Break Joint: Indicates a young sheep (Lamb).

      • Spool Joint: Indicates an older sheep (Mutton).

    • Meat Safety:

      • Inspection: Mandatory process to ensure safety as per HACCP guidelines.

      • Grading: Optional; undertaken for marketing and quality purposes.

    • HACCP: Hazard Analysis and Critical Control Points.

      • The first step in HACCP is always Hazard Analysis, which identifies potential hazards in food production.

    5. Genetics & Inheritance

    • EPDs (Expected Progeny Difference):

      • Statistical measure predicting an offspring's performance in comparison to its peers.

    • Note on EPDs: An EPD represents exactly half of the EBV (Estimated Breeding Value) as offspring inherit only 50% of their DNA from either parent.

    • Accuracy Ratings:

      • >0.7 indicates high confidence;

      • <0.4 indicates a "best guess" that is likely to change in future predictions.

    • Heritability (h2h^2):

      • Low heritability (0–0.2): Often associated with reproductive traits, indicating slow genetic progress.

      • High heritability (0.4–0.6): More common in carcass traits, supporting fast genetic advancements.

    • Dominance Types:

      • Codominance: Both traits are expressed simultaneously (example: Roan color in cattle = mix of red and white hairs).

      • Incomplete Dominance: Traits blend together (example: Mixing red and white colors produces gray).

    • Sex Traits:

      • Sex-Limited Traits: Both genders carry the genes, but only one sex exhibits the trait (example: only females produce milk).

      • Sex-Linked Traits: Genes that are specifically located on the X or Y chromosomes, impacting inheritance patterns.

    6. Economics & Zoonotic Disease

    • Economic Impact:

      • Foot and Mouth Disease (FMD) is specifically tied to Brazil and can spread within a radius of 100 miles from the outbreak.

    • Zoonotic Diseases: Defined as diseases that can pass from animals to humans, posing a significant public health risk.

    • Examples of Zoonotic Diseases:

      • Brucellosis/Tuberculosis: Primarily explains the reason for pasteurization of milk to ensure safety.

      • Rabies/Ringworm: Transmitted through direct physical contact.

    • > [!important]

    Selection Differential: The difference between the selected breeding parent and the average of the herd.
    Example: If the herd average EPD is 7 and the selected parent has an EPD of 11, the selection differential would be 4.

    • Closing Encouragement: Good luck this afternoon! Emphasize careful attention during math problems and trust in your instincts.