Genetics for Profit

Wayne R. Wagner, Ph.D.
Livestock Specialist
WVU Extension Service
10/1998

The challenge for the cow-calf producer is to produce an appealing and satisfying product for the consumer and to do so at a profit. This is no small task. Too often we try to oversimplify the requirements. Even with the most modern technology available, breeding beef cattle that are both productive and good tasting will be difficult because the bovine is genetically very complex.

Researchers are busy at work, mapping the bovine genome. This will allow us to use blood samples to determine the presence or absence of certain genes or groups of genes known to influence specific traits. This technology will be available to the industry in the very near future and is already available for some traits.

Times have changed in the beef industry, and those involved must learn to make appropriate changes too. Modern cattle producers will not only work hard, they he will also be good business people who design their production system to produce a product desired by consumers (beef). As a food producer, each of you must analyze your operation and your goals. This article targets producers with this goal:

Produce beef that is wholesome and tastes good to U.S. and world consumers at a profit.

In the past, too many of us have failed to define our target. Although our aim may be very good, have we been shooting at the right target? The National Cattlemen's Beef Association conducted a beef quality audit in 1995 to determine where the beef industry is and where opportunities exist to improve the product. Face-to-face interviews were conducted with restaurateurs, packers, retailers, and purveyors. Following is the list of the top 10 aggregate concerns of restaurateurs, retailers, and purveyors:

1. Low overall uniformity and consistency of product
2. Inadequate tenderness
3. Low overall palatability
4. Excessive external fat
5. Beef's price is too high for the value received
6. Insufficient flavor
7. Excessive weights of cuts and boxes of cuts
8. Inappropriate U.S. Department of Agriculture quality grade mix
9. Incidence of injection-site lesion is too high
10. Low overall cutability/yield too low

This sounds like a report card filled with Cs at best. As an industry and as individuals we have not been responsive to consumer needs or desires. The genetic decisions that each producer makes in sire selection impacts nine of ten concerns listed above.

The 1995 National Beef Quality Audit (NBQA) reported the current USDA slaughter mix and projected the ideal slaughter mix, Table 1. This suggests that although not all cattle need to be the same, as an industry we need to increase the proportion of cattle in the upper 2/3rds Choice and Prime grades, decrease the percentage of Select, and eliminate cattle that grade Standard and lower. In 1995, only 1% of cattle graded were Prime and only 11% were in the upper 2/3rds of the Choice grade. Furthermore, the NBQA also defined the ideal carcass weight to be a minimum of 600 pounds and a maximum of 850 pounds.

Table 1: 1995 Actual USDA Slaughter Mix and Projected Ideal USDA Slaughter Mixa

USDA Quality Grade

1995 Actual USDA Mix, %

Aggregate Ideal Mix, %

Prime

1

7

Upper 2/3rds Choice

11

21

Lower 1/3rd Choice

36

34

Select

47

38

Standard & Below

5

0

a 1995 Executive Summary - National Beef Quality Audit

With this information in hand you can define a target. Producers can breed for one of two targets, which is a decision that each needs to make. The first target will be "quality" oriented and will be achieved primarily by breeding British type cattle that excel in their ability to marble while minimizing their propensity to deposit external fat. The second target will be achieved by incorporating some continental breeding into the genetic makeup in order to produce USDA yield grade 1 and 2 cattle while maintaining enough propensities to marble to qualify for the Select grade and higher.

Carcass weight defines slaughter weight, which also is partially defined by frame size. Pinpointing the target becomes very difficult. Let me share with you a logical target for a commercial cow-calf producer and the way in which I would approach breeding for that target. Because you cannot eliminate all variability, my target for carcass weight would be 750 to 775 pounds, which is essentially a 1,200 to 1,225 pound live weight. Because of variation, most steers should fall into the 700-825 pound range and most heifers should fall into the 600-725 pound range. The target for USDA Quality Grade is Average Choice, so most should be Low Choice or better. The target for ribeye area is 12.5 to13.0 square inches or 1.05 to1.1 square inches per 100 pounds live weight. The target animal should kill at 0.4 inches of external fat or less and would have a yield grade of 2.8.

Value-based marketing is coming. Good cattle will bring premiums, and poor cattle will bring discounts. The days of selling on averages are limited. Many are beginning to "grid price" cattle. Table 2 lists seven cattle from the 1997-98 West Virginia Feedlot and Product Evaluation Program. These cattle were sold on the Gelbvieh grid. The grid price adjustments labeled Quality, Yield, and Conformance are the premiums and discounts for quality grade, yield grade, and conformance.

Table 2: West Virginia Feedlot and Product Information Program - Grid Price Evaluation

WV

FPIP

No.

S

e

x

Live

Wt.

Hot Carcass Weight

Quality Grade

Yield Grade

Grid Adjustments

Added Value

Quality

Yield

Conformance

32

S

1242

792

Prime

3

$52.65

$(7.92)

$4.12

$48.85

59

S

1389

875

C.A.B.

2

$14.42

$13.13

$4.55

$32.09

85

S

1283

808

Choice

2

$5.24

$12.12

$4.20

$21.56

131

H

1018

649

Choice

4

$4.21

$(129.80)

$3.37

$(122.22)

88

S

1122

707

Select

2

$(5.53)

$10.61

$3.68

$8.75

104

S

1108

705

Std

2

$(85.66)

--

--

$(85.66)

95

S

1297

825

Comm.

2

$(260.66)

--

--

$(260.66)

Once an endpoint is defined, a breeding program can be outlined. As a producer, you cannot focus on a single trait, but you must consider the whole animal and all traits simultaneously. It has been said that reproduction is six times more important than growth rate, which is now considered to be of equal or less importance than the final product (quality, yield, portion size). Fertility is extremely important, but few producers really target the genetics of fertility. One problem is that fertility is the sum total of the interaction and actions of several traits such as: mating behavior, semen quality, body condition, calving difficulty, gestation length, disease, feed quality, etc.

Although it is a complex trait, there are opportunities to genetically impact fertility. First, consider scrotal circumference in bulls. Data from Colorado State University and others have shown that scrotal circumference in yearling bulls is positive and highly related to sperm production. As scrotal circumference increases, age at puberty in half-sib females declines. However, these relationships are not perfect correlations. In addition, scrotal circumference measurements of non-contemporaries are not comparable. Scrotal circumference will vary because of feeding programs, temperature when bulls are measured, and human error in measuring circumferences. In my opinion, if you are serious about improving the genetics for fertility, yearling bulls with average and above scrotal circumference within their contemporary group should be selected. At the very least, the bottom 20% of the bulls in a herd or contemporary group should not be kept as bulls.

Secondly, consider the impact of body type on fleshing ability and its relationship to Body Condition Score (BSC). BCS is primarily determined by the amount and quality of feed available (non-genetic factors) and the fleshing ability and temperament of the animal (genetic factors). The reality is that cattle are ruminants and in most cases must be able to consume large amounts of roughage in order to meet requirements for maintenance, milk production, and tissue growth. Therefore, they should have some volume and dimension to their body to facilitate forage consumption. In addition, there seems to be a negative relationship between milk production and fleshing ability so the two traits need simultaneous consideration. The logical approach would be to avoid extremes in both traits. Mature cows should be able to maintain themselves in a BCS of 5 or 6 on forage without supplemental feed, including during the winter feeding program.

Finally, the impact of calving difficulty on death loss and rebreeding performance is of great importance, Table 3. It is well known that birth weight is highly related to calving difficulty, but if you select for low birth weight you sacrifice growth rate. Too much emphasis has been given to eliminating all calving difficulty when most producers can probably tolerate some small risk of calving difficulty. The result of selecting for low birth weight has been to accept less yearling weight and probably some reduction in overall feed efficiency.

Table 3: Effects of Calving Difficulty in Two-Year-Olds on Conception Rate and Percent Detected in Estrus a

   

During AI Period b

 

Group

No.

Detected in Estrus, %

Conception Rate, %

Total Conception Rate, %

No Difficulty

584

68.3

66.0

79.6

Assisted

366

59.3

50.6

71.4

Difference

 

9.0

11.6

8.3

a University of Nebraska
b AI breeding period was approx. 45 days followed by a clean-up period of approx. 25 days.

Table 3 indicates that the impact of calving difficulty in 2-year-old females is very costly. For example, during a 70-day breeding season, 2-year-olds that had experienced some calving difficulty had a 71.4% conception rate compared to a 79.6% conception rate in 2-year-olds that had no calving difficulty. In this study, 366 2-year-olds experienced some degree of difficulty compared to 584 head that had no difficulty. Data from Colorado State University (Table 4) show the effect of calving difficulty on death loss, calving interval and subsequent production in 2-year-old females. Heifers that had difficulty calving at two years of age weaned a 59% calf crop compared to a 70% calf crop for those heifers that had no difficulty as twos. In addition, those heifers that had difficulty calving as twos weaned a 63% calf crop as threes while those with no difficulty as twos weaned a 77% calf crop. Calves from the latter group were 46 pounds heavier at weaning, which was due in part to the fact that they were 13 days older.

Table 4: Associations of Calving Difficulty in Two-Year-Old Females with Total Productivity a

Group

No.

Calves Weaned as Twos, %

Calves Weaned as Threes, %

Calving Interval

2nd Calf Weaning Weights

Difficult Births

121

59

63

367

351

Normal Births

253

70

77

354

397

a Colorado State University

The production traits that are of importance are milk production, weaning, yearling, and mature weights. Milk production is important because of its impact on calf weaning weight. A cow should be able to produce enough milk to raise a good calf, but not so much that she has difficulty maintaining enough body condition to rebreed and calve in a 365-day interval. The ideal level of milk production will vary between herds.

The ideal weaning weight will vary among operations. A goal to maximize weaning weight is ill-advised and not the most efficient use of resources. This does not mean that the goal should not be to improve weaning weights, because an improvement in weaning weights while holding input costs constant will result in improved efficiency. The same argument can be applied to yearling weight. Efficiency will be improved if you can hold input costs constant and increase output (yearling/weaning weight) or increase production relatively more than an increase in input costs. Again, as a producer, one needs to simultaneously consider input costs and level of product output. Efficiency is really the trait we are interested in, not weaning or yearling weight. Efficiency can and will be improved by increasing weaning and/or yearling weight without increasing frame size. The concept that bigger (or heavier) is better is simply not true. A frame 5 calf that weighs 1,100 pounds at a year of age may be more efficient than a frame 6 calf that weighs 1,200 pounds at a year of age.

Mature size is frequently ignored, but it is highly related to maintenance costs. Logically, extremes should be avoided. If it appears as though I am suggesting that we should seek a "middle ground," it is because it is logical for most of the growth traits.

In addressing the topic of genetics for profit, I would indeed fail if I did not mention the importance of mating system. Crossbred animals tend to out perform purebreds because of heterosis. There is a significant amount of heterosis for fertility traits, some heterosis for growth traits, and little heterosis for product traits like quality and yield grades. The advantages of crossbreeding are greatest when you utilize a crossbred cow to produce a crossbred calf because you get improved fertility and milk production with the crossbred cow.

There are several crossbred systems that a producer could utilize such as a two- or three-breed rotation, a terminal sire, or a combination of a terminal sire in conjunction with a rotational system. A two-breed rotation where the two breeds are similar in mature size and milk production has the potential to improve efficiency 10% to12%. A two-breed rotational cross where the two breeds differ considerably in mature size and/or milk production is probably limited to a maximum improvement in efficiency of 5% and may actually decrease efficiency if the two breeds are extremely different. A terminal sire system utilizing a crossbred cow has the potential of increasing efficiency 10% to20% over a straight breed program.

Those factors that affect profit to the beef producer are:

1. Total herd production (weaning/yearling weight), not average weights of live calves.
2. Maintenance / feed costs.
3. Product value, which should reflect quality (USDA Quality and Yield Grade).
4. Value of culls (small cows and those with a BCS of less than 5 have a lower value/cwt.)

Over the past 20 years, too many producers have focused their attention on one or two traits rather than the whole animal. In doing so, the industry and breeders have had a tendency to breed for extremes in several traits such as low birth weights, high yearling weights, large frame size, and high milk production. The next extreme may be muscling or ribeye area. In reality, breeding for extremes will reduce overall profit to the industry. Cattle that are average to slightly above average in all traits will be the more profitable.