meats - exam c

Appraisal of market animals

• Knowledge necessary to evaluate market animals:

  • Relative merit

  • Market situation (supply & demand, recession, tariffs)

Relative Merit is determined by:

• Age

• Weight

• Sex

• Fatness

• Muscling

• All lead to value differences

Factors affecting Relative Merit - age

• As animals increase in age, they are likely to become:

  • Less tender: less soluble collagen, less fat

  • More flavorful: flavor stored in fat

  • Darker in lean color: myoglobin

  • Yellow in fat color: keratin in fat, mostly seen in beef cattle (dairy, white fat, beef, yellow fat)

  • Diseased: weaker immune system/ exposure to diseases

  • Fatter: metabolism slows

Not all species are affected equally!

Comparative effects of age on market value by species (old:young ratio)

Old:Young Ratios for Beef, Swine and Sheep

Reasoning for old:young ratios - why?

• Beef

  • Less tender

  • More intense in flavor

  • Darker lean color

  • Yellow fat color

• Swine

  • Fatter

• Sheep

  • Undesirable flavor

  • Higher condemnation rate due to higher incidence of disease

• In summary, swine are the least impacted species of meat animals, while sheep are the most impacted with respect to the negative effects of increasing age on the value of older animals

Factors affecting Relative Meritt - weight

As animals increase in weight:

• Their carcasses become fatter

• Their retail cuts become larger

Discounts for heavy beef carcasses

Consumers object to both fatness and excessively large (too costly/unit serving) cuts.

Factors affecting Relative Merit - sex

Sexes differ in:

• Dressing percentages

• Carcass proportions

• Cutability

• Palatability

• Acceptability

These 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 at 14 months (old crop lamb), Puberty at 8 months

• Issues seen in beef and old crop lamb

Dressing percentage

• Beef: Decrease 4 to 10% (heifers, some bulls). Heifers due to pregnancy; bulls due to heavier hides (and testicles) and heads and less fat

• Swine: No effect Decrease 4 to 10% in old crop lambs.

• Sheep: Same general reasons 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 is young bull less than 30 months old

  • Ranked based on leanness due to testosterone

• Swine: Boar > gilt > barrow

  • Gilt faster maturing than not intact male

• Sheep: Ram > wether > ewe

Palatibility

• Beef: Palatability Bullock (tenderness problem)

• Swine: Boar (flavor problem - “boar odor”)

  • In fat, pheromone

• Sheep: Ram (flavor problem)

Acceptability

• Beef: Acceptability 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

Net effects → intact males and females are usually priced lower than the castrated males of the species (with the exception of swine)

Fatness

• 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

• Mesenteric, kidney and intermuscular fat contribute little to firmness and appearance, retarding shrink and to palatability, but subcutaneous and intramuscular fat do.

Subcutaneous fat and intramuscular fat

• Correlation of subcutaneous fat to marbling is .24, explains about 5.8% of the variation

Red vs White muscle fibers

• Because of the relationship between red (Type I) versus white (Type IIB) muscle fibers and fatness-muscling, it is difficult to select for very muscular animals that marble.

  • Red type 1 muscle, slow twitch, FA energy

  • White, type IIB muscle fiber, glycolytic

• Predominately red (Type I) fibers: Angus, Jersey, Longhorn, Shorthorn (“running”)

• Predominately white (Type IIB) fibers: Charolais, Limousin, Maine Anjou, Gelbvieh

  • Continental Europe breeds

  • Designed tripurpose, usually heavily muscled and lean

Breeds with superior ability to deposit marbling

• Duroc

• Southdown

• Angus

Breeds with inferior ability to deposit marbling

• Yorkshire

• Merino sheep

• Limousin

Impact of marbling on price/cwt of beef strip loins

• Marbling plays an important role in the price of beef. A large portion of this price deals with supply/demand.

• Shows small changes in intramuscular fat can have a great impact on the price of beef subprimals.

Price/cwt for carcasses that vary in USDA yield grade

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&2:

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” (rib, loin, round, chuck) makes up 56% of total muscle weight of cattle of very different shapes and appearance (Butterfield and Berg).

Theories regarding muscling and responses 3

3. That muscle is always present in constant ratio and proportion to bone

False!

• Thinly muscled 2.5:1

• Normally muscled 3.5:1

• Thickly muscled 4.5:1

• Double muscled 5.5 to 8.5:1

  • Myostatin deficiency (Belgian blue), not selected bc c-sections and lower meat quality

Effect of cattle type on the ratio of major cuts (1/2-inch external fat trim) to bone

• Cattle do vary in muscle to bone and thus you cannot predict muscle:bone

  • Differences among English (Angus, Hereford), exotic (charolais and limousin), <50% bos indicus (Brahman), >50% bos indicus (Brangus/ Santa Gertrudis) breeds

• Steer has more bone than heifer

  • Heifer stops maturing earlier

• Holstein has most amount of bones/ larger bones

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

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, but age, fatness and muscling have endless combinations.

• It became obvious in the early 1920's that some common terminology (development of grades) had to be developed to facilitate:

  • Market news reporting

  • Transactions sight unsee

Estimated palatability (words)

• Beef: Prime, Choice, Select, Standard, Commercial, Utility, Cutter, Canner

• Pork: U.S. and U.S. Utility

• Lamb: Prime, Choice, Good, Utility, Cull

Estimated cutability (numbers)

• 1 best 5 worse

• Beef 1, 2, 3, 4, 5

• Pork 1, 2, 3, 4

• Lamb 1, 2, 3, 4, 5

Grading concepts

• Once the purpose is defined, specific traits in carcasses can be used to identify and stratify carcasses into homogeneous groupings.

• Heterogenous supply → homogenous groupings (A, B, C, D, etc.)

Grading schemes

• Dichotomous – two categories

  • Acceptable

  • Unacceptable

• Hierarchical – several entities arranged in a graded series

  • Superior

  • Good

  • Average

  • Inferior

Original concepts of beef carcass grading

• Group for elite consumers where taste was the only issue

• Groups for retail consumers with different priorities for taste and leanness

• Groups for further processed (ground, comminuted or prepared beef items)

  • Prime was identified for the elite consumers

  • Choice, Select and Standard for retail consumers

  • Commercial, Utility, Cutter and Canner for manufacturing beef

Cutability grades - beef

• Developed in the 1960's as more accurate ways to segment carcasses based on the yield of closely trimmed, boneless retail cuts because it was possible to have very lean and very fat Choice carcasses. In the cutability systems for beef, pork and lamb, the following are important measures that are closely related to carcass composition:

• Beef

  • Size: carcass weight (decreases cutability)

  • Muscling: ribeye area

  • Trimmable fat: adj fat thickness, 12th rib

  • Internal fat: kidney, pelvic, heart fat %

Cutability grades - swine, lamb

• Swine

  • Size: none

  • Muscling: muscling score

  • Trimmable fat: backfat, last rib

  • Internal fat: none

• Lamb

  • Size: none

  • Muscling: none

  • Trimmable fat: adj fat thickness, 12th rib

  • Internal fat: none

Fatness and muscling impacts on retail cut yields

• Fatness – as fatness increases, retail cut yield decreases.

• Muscling – as muscling increases, retail cut yield increases

To produce a desirable carcass:

• Full feed

• Market when ready

• Do not hold

Full feed

Why full feed? Well-bred animals with high inherent potential for growth will produce most efficiently on a full feeding program (high plane of nutrition).

Priority of nutrient utilization (tissues with the greatest importance to life are first priority):

A. Highest priority: nervous tissue, in head, perinephric fat deposit

B. Middle priority: skeletal tissue, in neck and shoulder, intermuscular fat deposit (seam fat)

C. Low middle priority: muscle tissue, in hind limb, subcutaneous fat deposit

D. Lowest priority: fat, in rib and loin, intramuscular fat deposit (marbling, most important to us)

Full feed - High vs low plane of nutrition

The higher the plane of nutrition, the more rapidly optimum composition is achieved

Market When Ready - Growth curves

Market ready - slaughter point for optimal carcass tissue proportions

• At some point and with the inherent growth potential of the specific animal involved, the proportions of muscles, bone and fat are optimal.

• Based on the majority of the animals with which we work, optimal carcass tissue proportions are attained at 1,300 pounds for cattle, 280 pounds for swine and 120 pounds for lamb.

• If slaughter later, over fat carcass (over finished), slaughter too early, too lean (under finished)

Market ready - sex class/ breed differences in composition at different slaughter points

• Slaughter Angus at point 1, Charolais point 2 for optimal finishing, doesn’t exactly happen in packing due to mixing of cattle

Average vs value based marketing

• Value based marketing: each carcass gets graded individually, highest valued carcass gets benefits, lower ones don’t

• Average based marketing: putting cattle together as an average (mixing them together) to balance prices if some cattle don’t grade

  • Only downside is higher grading carcasses bring up value of lower grading cattle

Optimum carcass composition

Obviously, optimal weight or age at which to slaughter market animals differs among sex classes and among breeds: Steers versus heifers, steers versus bulls, Charolais versus Angus, Chianina versus Shorthorn, etc. This is primarily a difference in composition caused by either hormonal activity or by frame size and maturity.

Marbling between frames

Adjusted fat thickness, 12th rib among frames

Do not hold (and what happens if want to hold)

• What happens if we allow the animal to go beyond the point in weight at which it would produce the optimal carcass composition

  • Decreased rate of gain

  • Decreased feed efficiency

  • Undesirable carcass composition

• Holding happens because withdrawal period or catastrophic events like COVID or 9/11 happen in market