TAMU ANSC 307 - Exam 3 Study Guide (13 pages)

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Exam 3 Study Guide

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Exam 3 Study Guide


Exam 3 review for lectures 16-20

Study Guide
Texas A&M University
Ansc 307 - Meats
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ANSC 307 1nd Exam 3 Study Guide Lectures 16 20 Lecture 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 Merit Age 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 disease Weight 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 value Cut Size effects For hams the larger the ham the lesser the value Sex Sexes differ in Dressing percentages Carcass proportions Cutability Palatability Acceptability Differences 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 deposition Swine 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 months Swine Boar gilt barrow Sheep 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 problems Swine No effect Sheep Ewes may have class designation of Yearling Mutton because of earlier maturity Net 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 marble Red require marbling as energy heavy muscle white use glycogen for energy Breeds with superior ability to deposit marbling Duroc hogs Southdown lambs Angus beef Breeds with inferior ability to deposit marbling Yorkshire hogs Merino sheep Limousin cattle Predominately 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 1 Effect of cattle type on the ratio of major cuts to bone 1 Holsteins have a large amount of bone not a lot of muscle 2 Steers have more bone than heifers heifers have more fat Cattle do vary in muscle to bone so you cannot predict muscle bone Interaction 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 fat Lecture 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 will provide Carcass value depends upon Age Weight Sex Fatness Muscling Of these weight and sex are easily described age fatness and muscling have endless combinations It became obvious in the early 1920 s that some common terminology had to be developed to facilitate market news reporting and transactions sight unseen Estimated

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