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TAMU ANSC 307 - Exam 3 Study Guide
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ANSC 307 1nd Exam # 3 Study Guide Lectures: 16 - 20Lecture 16 (November 10) Appraisal of Market Animals Appraisal of market animals = knowledge necessary to evaluate market animals (relative merit and market situation). Relative Merit is determined by: - Age - Weight - Sex - Fatness - Muscling Factors affecting Relative MeritAge As animals increase in age, they are likely to become: - less tender - more flavorful ,- darker in lean color - yellow in fat color- diseased - fatter Not all species are affected equally Comparative effects of age on market value by species (old:young ratio): Old/ Young x 100-Old animal is worth half as much as a young animal; young animal worth twice as much as old Old: young ratios for Beef, Swine, and Sheep: - 1. Swine- least impacted - 2. Beef- 3. Sheep- most impacted Why:Beef- less tender, more intense flavor, darker lean color, yellow fat color Swine- fatter (can have max of 50% fat)Sheep- undesirable flavor, condemnation due to higher incidence of diseaseWeight:As animals increase in weight:- Their carcasses become fatter - Their retail cuts become larger Consumers object to both fatness and excessively large (too costly) cuts.Fatness effects:- For lamb carcasses, the heavier the carcass, the lesser the valueCut Size effects:- For hams, the larger the ham, the lesser the valueSex: Sexes differ in: - Dressing percentages - Carcass proportions - Cutability - Palatability - AcceptabilityDifferences are the result of age at marketing versus age at puberty: - Beef: market at 18 months, puberty at 12 months- Swine: market at 7 months, puberty at 7 months- Sheep: market at 8 months (Spring lamb) or 14 months (old crop lamb), puberty at 8 months *More problems for species that don’t market at puberty (beef and old crop lamb), no problems for swine or spring lamb Dressing percentage: Beef: Decrease 4 to 10% (heifers, some bulls). Heifers due to pregnancy; bulls due to heavier hides and heads and less fat Swine: No effect Sheep: Decrease 4 to 10% in old crop lambs. Same as for beef Carcass proportions:Beef: Chuck +2% in bulls due to crest development; flank +2% in heifers due to udder fat depositionSwine: No effect Sheep: Shoulder +3% in old crop rams due to development of secondary sexual characteristics Cutability: Beef: Bullock > steer > heifer *Bullock= young bull <30 monthsSwine: Boar>gilt>barrowSheep: Ram > wether > ewe Palatability:Beef: Bullock (tenderness problem) Swine: Boar (flavor problem — "boar odor") Ram (flavor problem) Acceptability:Beef: Class designation, "Bullock" because of toughness problemsSwine: No effect Sheep: Ewes may have class designation of "Yearling Mutton" because of earlier maturityNet effects: intact males and females are usually priced lower than the castrated males of the species (with the exception of swine) Fatness Contributes: - firmness and appearance to cuts - retards cooler shrink - retards cooking shrink - contributes to palatability Fat is deposited in the following sequence: Mesenteric, Kidney, Intermuscular, Subcutaneous, Intramuscular (marbling)- Mesenteric, kidney and intermuscular fat: contribute little to firmness and appearance, retarding shrink and to palatability- Subcutaneous and intramuscular fat do contribute- Correlation of subcutaneous fat to marbling is .35 (explains about 12% of the variation, 88% unknown)**Because of the relationship between red versus white muscle fibers and fatness-muscling, it is difficult to select for very muscular animals that marbleRed require marbling as energy- heavy muscle; white use glycogen for energyBreeds with superior ability to deposit marbling: - Duroc hogs- Southdown lambs- Angus beefBreeds with inferior ability to deposit marbling - Yorkshire hogs - Merino sheep- Limousin cattlePredominately red fibers: (British breeds); marbling, less muscular - Angus, Jersey, Longhorn, Shorthorn Predominately white fibers: (continental breeds); lean, muscular - Charolais, Limousin, Maine Anjou, Gelbvieh Impact of marbling on the price of beef strip loins (IMPS #180): - Slightly Abundant, Moderate, Modest, Small, Slight Traces- Marbling plays an important role in the price of beef. A large portion of this price deals with supply/demand- More marbling, higher value Acceptable/ Trimmable fat:- Acceptable: In market animals, we require a certain quantity of subcutaneous fat- Trimmable: we grossly penalize that fat that is considered in excess)- In today's market, we sort carcasses into groups of "Y 3's or better," "Y 4's" and "Y 5's" because the trim level we consider acceptable is 1 inch or less. As trim levels decrease over the years, the line for acceptability will likely shift to the left.Muscling: Growth gradients for muscling: - Starts at extremities (forelimbs and hindlimbs)- Moves upward (chuck and round) - Progresses forward from rump and backward from withers - Meets at rib-loin juncture Theories regarding muscling and responses:(1) That long-bodied, tall stretchy animals are more muscular and/or yield higher percentages of steaks from certain areas of the carcass.FALSE: With increased length of loin and rib sections, the flank and plate sections are longer, too. Thus, no net effect from a percentage standpoint. (2). That you can select for heavy muscling in the loin and/or round (or leg or ham) and select against muscling in the chuck or shoulder. FALSE: Muscles grow in concert. Thus, as you select for increased muscle in the round, muscles in the chuck will also increase. "Expensive Muscle Group" makes up 56% of total muscle weight of cattle of very different shapes and appearance (Butterfield and Berg).(3). That muscle is always present in constant ratio and proportion to bone.FALSE: Muscle:Bone Ratio: - Thinly muscled- 2.5:1- Normally muscled- 3.5:1 - Thickly muscled- 4.5:1 - Double muscled- 5.5-8.5:1Effect of cattle type on the ratio of major cuts to bone:1. Holsteins have a large amount of bone, not a lot of muscle2. Steers have more bone than heifers; heifers have more fat- Cattle do vary in muscle to bone, so you cannot predict muscle: boneInteraction of fatness and muscling on cutability:- Leanness: ratio of total muscle to total fat - Muscling: ratio of total muscle to total bone - Meatiness: ratio of total muscle plus acceptable fat to total bone plus trimmable fatLecture 17 (November 17) USDA Slaughter Animal and Carcass Grades Grades: Groups of livestock of similar market desirability in terms of predictions of the type of carcass they


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TAMU ANSC 307 - Exam 3 Study Guide

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