Appraisal of Market Animals

(1) To determine how age, weight, sex, fatness and muscling affect the value of livestock.
(2) To show why some breeds of livestock have different abilities to deposit fat.
(3) To relate actual present day market conditions that are due to the relative merit of livestock.

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)

Why?

Beef

• less tender
• more intense flavor
• darker lean color
• yellow fat color

Swine

• fatter

Sheep

• undesirable flavor 
• 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 the the negative effects of increasing age on the value of older animals.

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/unit serving) cuts.

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

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

Fatness

Contributes:

(1) firmness and appearance to cuts

(2) retards cooler shrink

(3) retards cooking shrink

(4) 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.

Correlation of subcutaneous fat to marbling is .44 (explains about 20% of the variation)

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

Predominately red fibers ---> Angus, Jersey, Longhorn, Shorthorn

Predominately white fibers ---> Charolais, Limousin, Maine Anjou, Gelbvieh

Marbling plays an important role in the price of beef. A large portion of this price deals with supply/demand. The above chart demonstrates that small changes in intramuscular fat can have a great impact on the price of beef subprimals.

In market animals, we require a certain quantity of subcutaneous fat (termed acceptable), but we grossly penalize that fat that is considered in excess (termed trimmable). 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:

(1) starts at extremities (forelimbs and hindlimbs)

(2) moves upward (chuck and round)

(3) progresses forward from rump and backward from withers

(4) meets at rib-loin juncture

Theories regarding muscling

(1) That long-bodied, tall stretchy animals are more muscular and/or yield higher percentages of steaks from certain areas of the carcass.

(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.

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

(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

Thinly muscled 2.5:1

Normally muscled 3.5:1

Thickly muscled 4.5:1

Double muscled 5.5-8.5:1

 

Source: Knapp et al., J. Anim. Sci. 67:2294 (1989)

Cattle do vary in muscle to bone and thus 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

Review of Material -- What the student should know:

(1) The reason why different prices are paid for different products.

(2) Concepts related to what happens to animals when they get older, heavier, are from different sex-classes, are fat or are heavy or light muscled.

Links to related sites on the Internet

Value-Based Marketing of Beef