Meat Quality in Cattle Live Evaluation

Mark F. Miller Jason H. Byrd

Texas Tech University, Lubbock, Texas, U.S.A.

INTRODUCTION

Meat quality can be identified as those factors that affect the palatability of tenderness, flavor, and juiciness of meat products. Meat quality evaluations in the live animal try to predict eating quality and overall consumer satisfaction of meat products. The United States Department of Agriculture (USDA) established a set of standards commonly referred to as USDA quality grades, which predict the expected beef meat quality. These USDA quality grades take into account the amount of intramuscular fat and the overall maturity of the animal. Quality grades are administered by USDA graders after the animals have been harvested and chilled at least 18 hours. Quality grades include Prime, Choice, Select, and Standard for young cattle (A or B maturity), and Commercial and Utility for mature cattle (C, D, or E maturity). Prime and Choice are the target grades, and are used to designate beef with the highest eating qualities.

Cattle buyers are faced with the tremendous challenge of predicting these USDA quality grades on a live basis. If the quality grade of an animal is correctly estimated, then the price will be more fair for both the buyer and seller. This requires tremendous skill and a great deal of experience.

INTRAMUSCULAR FAT EVALUATION Breed Type

One of the most influential factors that influences quality grade in cattle is breed type. Different breeds of cattle deposit fat at different rates. English cattle in general (Angus, Red Angus, Hereford, Shorthorn) deposit intramuscular fat at the fastest rate and are commonly associated with higher quality grades. Dairy breeds also tend to grade well because intramuscular fat is related to milk butterfat and total milk production. On the other hand, Exotics (Charolais, Limousin, Chianina) and Bos indicus cattle (Brahman, Bonsmara, Tulie) deposit low levels of marbling.

Fat Thickness

Fat thickness is the measurement of subcutaneous fat opposite the 12th rib, and relates highly to meat quality. Dairy cattle require a minimum of 0.2 inch of backfat to reach the Select grade and 0.35 inch to grade Low Choice. English cattle typically need 0.4 inch to grade Low Choice. Exotic cattle generally need 0.4 inch to grade Select, and 0.5 inch to reach Low Choice. Bos indicus cattle require 0.6 inch of backfat to grade Low Choice.

Muscle/Cattle Thickness

Muscle thickness and cattle thickness are other factors that greatly affect quality grade. Generally speaking, heavy-muscled cattle do not quality grade as well as light-muscled cattle. Cattle thickness is variable. If the thickness is due to fat, animals grade higher. However, if the thickness is due to muscle and not fat, then cattle thickness doesn't correlate with increased quality grade.

Trained live cattle evaluators look at many specific places on an animal's body to help correctly estimate quality grade. One of the most important places to evaluate is tail pones (fat deposits that accumulate around the tail-head of an animal) (Fig. 1B).[1] The larger the tail pones, the higher the cattle graded for English, Dairy, and Exotic cattle.[2]

Lower Quarter

Lower quarter (Fig. 1E) refers to the fat deposits along the inner thighs of the animal. Lower quarter has a positive relationship with quality grade.[2] This trait is most effective when predicting quality grade of English cattle and is the second most useful trait when all breeds are considered.

Cod/Udder Fat

Cod/udder fat (Fig. 1D) has been used to predict quality grade on live cattle. Cod fat isn't very reliable because it is too dependent on how the animal was castrated. If the

Fig. 1 A diagram showing where various live animal quality grade indicators are located: A. Turn over the top, B. tail pones, C. round creases, D. cod/udder, E. lower quarter, F. dewclaws, G. flank, H. brisket, I. jowl, J. cheeks.

animal was castrated up high on his scrotal sac, then there is no room for the fat to deposit. Also, if he was castrated at the base of the scrotum, then he will deposit lots of cod fat early on, and estimation errors can occur. This trait is highly dependent on breed type. It is most accurate on Brahman cattle, and doesn't work well in Dairy cattle.[2]

Brisket/Flank

The brisket and flank (Fig. 1G and H) are two of the most influential traits on quality grade.[1] Cattle with very full, wide briskets generally grade higher than those with sharp, angular briskets. Also, deep-flanked cattle grade higher than shallow-bodied cattle. These two areas were found to be most accurate in evaluating English and Exotic cattle.[2]

Cheeks/Jowl

Cheeks and jowl (Fig. 1I and J) are other factors that can be used to successfully predict quality grade.[1] As an animal reaches the Choice grade, its cheeks become very ''puffy'' and full. The same is true for its jowl area. Fullness of the cheeks and jowl relate to quality grade across all breeds studied.[2]

Turn Over the Top

One of the more modern places to evaluate quality grade on live cattle has been the turn over the top (Fig. 1A). This expression refers to how wide an animal is over the loin and rib, and how sharp appearing their top is. Fatter cattle will have a wide top, with a very gradual turn. Generally, cattle with a ''rooftop'' shape over their top will not grade as well as those with a wide turn.

Round Creases

In heifers round creases (Fig. 1C) are a useful tool for predicting meat quality.[1] As heifers begin to get fatter, the area below their vulva will fill in with fat and creases will begin to be visible. They will look like folds of skin that extend down on both sides of the animal. This trait has been found to be the most useful trait in predicting live quality grade on Bos indicus females.[2]

In the 1940s and 1950s, ''old time'' cattle buyers on the river markets used dewclaws (Fig. 1F) to predict meat quality.[1] Their consensus was that if the dewclaws pointed toward the ground, then that animal wasn't ready to be slaughtered and would not quality grade very high, but if the dewclaws pointed out or even slightly upward, then the animal was ready and would quality grade well. In today's markets, dewclaws are not given that much emphasis by current live animal evaluators. However, research does show a positive relationship between the directions of the dewclaws and quality grade, especially in Black, English-type cattle.[2]

Disposition

Disposition has long been linked to meat quality in cattle. Calmer, more docile animals have the ability to deposit marbling (intramuscular fat) at a higher level than cattle that are ''excitable.'' Also, more docile animals tend to have fewer incidences of major carcass defects (blood splash, bruising, fiery fat, etc.) than highly excited animals. Swirl has historically been used to predict docility. Swirl refers to the swirl pattern of hair on the animal's forehead. It is said that the lower the swirl, the more docile the animal will be. The reverse is true for animals with very high swirl patterns. Docility was found to be highly related to quality grade in Exotic and Bos indicus type cattle.[3]

Growth Implants

Another important consideration when predicting meat quality in live cattle is whether they were implanted or nonimplanted. Growth implants are commonly placed in cattle's ears in an attempt to increase weight gain and growth. Research shows that implanting cattle can negatively affect quality grade anywhere from 0 30%. Live cattle evaluators use this information and sometimes this factor to determine quality grade if an animal is on the border between two grades.

MATURITY EVALUATION

A major factor to consider when predicting quality grade on live animals is maturity. In order for an animal to be eligible for USDA quality grades of Prime, Choice, Select, or Standard, the animal must be young (A or B maturity). Maturity is important, because as animals age, the meat greatly decreases in tenderness. Tough meat leads to consumer dissatisfaction. The following is a chart that relates maturity to age in months:

Age (months)

9 30

30 42

42 72

72 96

>96

Maturity

A

B

C

D

E

Classification

Young

Young

Mature

Mature

Mature

cattle

cattle

cattle

cattle

cattle

Live maturity evaluation is very subjective in nature. Trained personnel have few tools at their disposal. However, there are a few factors that can predict age of an animal. Trained evaluators will look at an animal's tail to predict maturity. As an animal ages, its tail will grow longer and be closer to the ground. Also, the switch (cluster of hair) at the end of the tail will get very coarse in nature as an animal matures. The head is another factor to consider when predicting maturity. The head of an older animal will be proportionally larger compared to its body. Young cattle will look normal and be very proportional.

As one can conclude, live evaluation of meat quality in cattle is extremely subjective. According to Fred L. Williams, Jr. (USDA), a trained expert can expect to be correct only about 70% of the time. A person should play the law of averages to be the most accurate. Live cattle evaluation is very important in today's cattle industry. Cattle buyers make purchases according to how good or bad they believe a pen of cattle will grade. It is up to them to decide which cattle will have the greatest chance of grading the best. If they can accurately predict meat quality, then consumers should receive a tender, juicy, flavorful piece of meat that they will enjoy time and time again.

REFERENCES

1. Boggs, D.L.; Merkel, R.A.; Doumit, M.E. An Integrated Approach to Evaluation, Grading, and Selection. Livestock and Carcasses, 5th Ed.; Kendall/Hunt Pub.: Dubuque, IA, 1998.

2. Williams, F.L., Jr.; Miller, M.F. Advanced Quality Grading: Slaughter Cattle; USDA. CEV Multimedia: Lubbock, TX, 1998.

3. Grandin, T. Problems with Bruises and Dark Cutters in Slaughter Steers/Heifers. In Improving the Consistency and Competitiveness of Beef A Blueprint for Total Quality Management in the Fed Beef Industry. The Final Report of the National Beef Quality Audit 1991; 1992. Colorado State University, Ft. Collins, CO; Texas A&M University, College Station, TX.

4. Schertz, M.J. Evaluation of Quality Grade Indicators for Live Slaughter Cattle. In A Thesis in Animal Science; Texas Tech University, May 1999.

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