What Type of Beef Cattle Production System Does Texas Use

By Stephen P. Hammack

Alogical genetic strategy for a beefiness moo-cow herd should include four steps. Kickoff, determine your production conditions (including climatic, provender and marketing) and the levels of animal performance that fit those conditions. 2nd, choose a breeding organization. Tertiary, identify the biological types and breeds within those types that are uniform with the start 2 considerations. And fourth, select for breeding the about useful individuals inside those breeds.

There are near 75 breeds of cattle in the Usa, with 15 or and so most common. Commercial moo-cow/dogie producers who confine themselves to one breed have straight- bred herds. If more than than one breed is used, the herd is crossbred.

Straightbreeding

Straightbreeding simply ways using the same brood for both sires and dams. Depending on the groundwork of the breed, straightbreds generally have more than uniform visible characteristics than about crossbreds. Straightbreeding is the simplest organisation to operate.

Inbreeding occurs over time in any breed, peculiarly in breeds closed to exterior convenance stock. This can reduce performance (called inbreeding depression), especially in traits such every bit fertility, livability, and longevity. Ane type of inbreeding is linebreeding, which tin, through carefully planned matings, elevate the influence of a genetic line or individual while minimizing inbreeding over all.

Crossbreeding

Crossbreeding begins with the mating of two purebreds of dissimilar breeds. This results in first-cross progeny, termed F1. There are three potential benefits of crossbreeding—heterosis, favorable breed combinations, and complementarity.

Heterosis

Heterosis, also called hybrid vigor, occurs when the functioning of crossbred progeny is different (usually amend) than the average of their parent types, as shown in the example in Figure 1. This case illustrates straight heterosis, the event of a crossbred individual's gene combinations on its performance. There tin can also exist maternal heterosis, or the indirect event of a crossbred dam'southward factor combinations that influence her calf's performance through the maternal environment she provides.

Heterosis is the contrary of inbreeding low, so information technology is greatest in the progeny of least related parents. For example, there is greater heterosis in crossing the less related breeds Hereford (created in the British Isles) and Brahman (created from cattle originating in due south central Asia) than in crossing the more closely related breeds Hereford and Angus (both originating in the British Isles).

Heterosis is reduced when both parents contain the aforementioned breed. In that location is no loss of heterosis if the parents share no breed in mutual, whether the parents are purebreds or crossbreds.
If an F1 is bred to either of its parent breeds (called a backcross), heterosis in its progeny is about half of that expressed in the F1.

If the F1 is not backcrossed but is bred to a 3rd breed, or an unrelated crossbred, at that place should exist no loss of heterosis in its progeny considering the sire and dam accept no breed in common as in a backcross.

If two F1s of the same cross are mated, the progeny, chosen F2, should have almost half the heterosis of the F1. However, if F2s and subsequent generations of this cross are intermated, their progeny boilerplate no additional loss of heterosis except for any inbreeding that might develop over time. This is a factor in creating combination breeds or using a composite breeding system every bit discussed later.

Characteristics express heterosis differently. Heterosis tends to be highest in fertility, livability, and longevity; intermediate in milk production, weight proceeds, feed efficiency, and trunk size; and lowest in carcass traits.

Even with the do good of heterosis the crosses from mediocre parents ordinarily do non perform as well every bit superior purebreds. And then, the most productive crossbreds come from genetically superior parents.

Favorable Brood Combinations

Even without heterosis there can be benefits merely from combining breeds. For instance, breeds with loftier carcass quality are generally not well adapted to tropical conditions, and those that practice have good tropical adaptability usually have relatively low carcass quality. Crossing breeds of these ii types can produce progeny with an acceptable intermediate level of both traits. Such favorable breed combinations can be the most important benefit of crossbreeding. They are the primary motivation for creating new breeds by combining existing breeds, equally discussed in the Combination Breeds section.

Complementarity

Complementarity requires dissimilar sires and dams. Complementarity results not but from the favorable combination of different types merely also from the style in which they are combined. Equally stated, the progeny of a brood with high carcass quality crossed with a breed with tropical adaptability have a blend of those traits. Simply the most productive and efficient way to conduct this cross is to use sires with high carcass quality and dams that are adjusted to tropical conditions. The opposite is not as effective because the dams are non well adjusted and information technology is the dams that must perform year-round under prevailing conditions.

Some other example of complementarity is the utilise of large sires on smaller dams. The result is that dams produce a higher percentage of their weight, and do information technology more efficiently, than if they were bred to sires of similar size. This type of complementarity also can be realized in straightbreeding by using genetic variation within a brood. Merely information technology is done more effectively with crossbreeding.

Types of Breeding Systems

At that place are two basic breeding systems in commercial production. If replacement females are produced in the herd the system is continuous. If heifers are non put back in the herd, but are brought in from outside, the arrangement is terminal.

Calves from continuous systems accept two functions: Some heifers are saved for replacements and get back into the herd, while the residuum of the calves are grown and/or finished to produce beef. But all calves from final systems accept but one use—the production of beef. (A modest segment of producers specialize in producing replacement females to be marketed to other producers.)

There tin can be combinations of continuous and final systems. Producers should understand the differences in these systems to avoid inefficient and costly mistakes.

Continuous

Since a continuous system produces its replacement females, information technology requires only external sires to avoid inbreeding. Because replacement females are retained, the cow herd has genetics from both sires and dams. If sires accept genetics for traits that are undesirable in brood cows, those traits are perpetuated in the cow herd.Therefore, both sires and dams should have a similar level of expression of important traits, without whatsoever undesirable characteristics. Genetic extremes generally do not fit. Continuous systems tin be either straightbred or crossbred.

Final

In a terminal system, replacement females come from outside the final-cross herd. Replacements can be either purchased or produced in another herd. Since heifers are not retained for convenance at that place is more flexibility in choosing types of sires and dams. Genetics for maternal power are irrelevant in terminal-cross sires considering their female progeny are not saved for replacements. However, genetics for maternal ability are important in sires that produce the females used for a last cross.

Last crossing is the only system in which complementarity can be realized. However, merely implementing a terminal system does not guarantee complementarity; sires and dams must exist different and they must possess complementary traits. Specialized types can be used in final systems to have maximum advantage of complementarity by exploiting their potent points while minimizing or eliminating weak points. Terminal systems are usually crossbred simply can be straightbred.

Continuous Crossbreeding Systems

True Rotations

True rotation systems use two or more breeds and the same number of convenance groups. The simplest truthful rotation uses 2 breeds and is sometimes called a crisscross (Fig. 2). A different breed of sire is used in each of two breeding groups. Replacement heifers are moved (rotated) from the grouping where they were produced to the other grouping, where they are mated to the breed that is not their breed of sire to minimize loss of heterosis in the system. Females remain in that breeding group, with the same breed of sire, for all of their lifetime mat- ings. Over time, females in the 2 groups gravitate toward a limerick of 2-thirds of the breed of their sire and one-third of the other brood. If a rotation has three or more breeds, a heifer is moved to the convenance group with the breed of sire to which she is least related to ensure minimal loss of heterosis.

Because they require multiple breeding groups, true rotations increase the complexity of a breeding plan. (Artificial insemination tin can simplify the mechanics, merely not the management, of some crossbreeding systems.) Likewise, a compromise must be fabricated between complementary matings and uniformity among groups. Because of these complexities and limitations, truthful rotations are uncommon, peculiarly those involving more than than two breeds.

Sire Rotations

Sire rotations are sometimes called rotations in time. Instead of rotating heifers out of the breeding grouping where they were produced to another breeding group, as in truthful rotations, sire breeds are rotated periodically in a unmarried convenance group. The number of years a sire breed should be used depends partly on how often heifers are put dorsum in the herd. As is true with all convenance systems, astringent inbreeding should be avoided; therefore, sires should be changed at least when necessary to avoid breeding them to their daughters.

There is less heterosis in sire rotations than in truthful rotations, though the reduction is slight in well-planned systems. Loss of heterosis is minimized by: 1) keeping replacement heifers out of dams least related to the heifer's brood of sire, and ii) minimizing breeding to the brood of sire.

Instead of using known breed limerick, some producers use visible breed characteristics and other visible features to make up one's mind whether to go on a heifer for a replacement; this can reduce phenotypic variability, only also reduces heterosis.

Sire rotations are easier to acquit than true rotations because there is only i breed- ing grouping. This is a common way to crossbreed.Unfortunately, many sire rotations can not really be called systems because they are implemented haphazardly with no logical plan for changing sires.

Terminal Crossbreeding Systems

Static Terminal

In a static terminal organisation, replacement females are either purchased or produced in another herd. Purchasing females simplifies the operation of this system because the only breed- ing grouping needed is for the terminal cross. A straightbred terminal is possible, but there normally is no expert reason to practise and so (unless a producer does not desire to save and manage heifers in a continuous straightbred system) because the benefits of crossbreeding are absent.

A ii-breed static system, using purebred sires and dams of dissimilar breeds, produces direct heterosis in crossbred calves. However, this system forfeits the considerable advantages of maternal heterosis from crossbred dams.

A 3-breed last is more productive and efficient. 2 breeds with desirable maternal traits are crossed to produce adapted and productive F1 dams, which are bred to sires of a third breed in a terminal cantankerous. Effigy 3 shows a complete three-breed static final system. In the complete system, about 1-4th of the dams must be straightbred, near one-fourth are needed to produce the F1, and only virtually one-half are available for the terminal cross.

Static terminal crossing is the only system that can accept maximum heterosis in both cows and calves, favorable breed combinations, and the bonus of complementarity. However, these advantages are tempered past the necessity of purchasing replacement females or producing them outside the terminal cantankerous.

Rotation-Terminal

A rotation-terminal combines continuous and terminal systems. Information technology is ane manner to provide crossbred replacement females for static terminals. A rotation arrangement, either true rotation or sire rotation, produces replacement females both to proceed itself going and to employ in a separate terminal herd. Middle-aged dams (4 to 6 years quondam) are moved out of the rotation to the terminal considering they are less prone to calving issues if last sires are relatively big.

You lot must have multiple convenance groups for rotation-concluding systems—one or more for the rotation, depending on whether it is a true rotation or sire rotation, and ane for the terminal cross. (A rotation-terminal system can exist approximated in one convenance group past using a multiple- sire-breed system, discussed below.) About half of the dams are needed in the rotation to provide enough replacements for the entire system, leaving about half of them for final crossing. Approximately ii-thirds to iii-fourths of auction calves come up from the final, with most of the balance being male calves from the rotation.

Heterosis is relatively loftier in rotation-terminals because all progeny and dams are cantankerous- bred. Yet, since a high percentage of females from the rotation must be retained to provide replacements for both the rotation and the terminal, there is little opportunity to select individual females for breeding.

Combination Breeds

Existing breeds are sometimes blended to grade combination breeds, with new packages of traits. Because these breeds are formed by crossbreeding, there is some rest heterosis; how much depends on how many breeds are included, in what portions they are included, and how much inbreeding occurs as the breed develops. So with these combination breeds information technology may be possible to obtain some heterosis using a single breed in a straightbred system.

The outset of these combination breeds in the U.S. was the American Brahman, created by combining several Bos indicus (humped) breeds imported from Republic of india or Brazil. A number of breeds have been created in the southern U.S., especially in Texas, by combining different biological types. Most of these comprise Brahman and British or, in a few cases, Brahman and Continental European breeds; they are generally called American breeds. More recently, some British and Continental combinations accept been made; these are less common but are increasing in number.

Other Systems

The breeding systems discussed then far all apply a single breed of sire in a breeding group. There are alternatives.

Multiple Sire Breed

More than one sire breed tin be used concurrently in a unmarried breeding grouping. For example, sires of two British breeds could be used in a continuous system. To reduce loss of heterosis and decrease phenotypic variability, retained replacement heifers should be intermediate in appearance, as much as possible. Or, British-breed and American-breed sires could exist used. If so, heifers with a more American-breed appearance should be retained if that type is better adapted to the prevailing production conditions. These systems are similar to 2-brood rotations.

A sire breed with desirable maternal characteristics and a terminal-sire breed could exist used with heifers retained from the maternal-type sires, if they can be visually identified. More than ane maternal-type sire breed could exist used, either meantime or in rotation over the years, to gain some maternal heterosis. These plans are similar to static terminal or rotation-terminal crossing.

Multiple-sire-breed systems have shortcomings. In that location is less heterosis than in similar but more controlled systems. If large last sires are used at that place is no way to forbid their matings of some of the younger females, and then calving difficulty may increment. Genetic variability among individuals is greater, just phenotypic variability may non be greater if close attending is paid to the pick of replacement females. The number of calves born relative to the ratio of sire breeds can vary from twelvemonth to yr, then the supply of potential replacement heifers too can vary. Large, extensively managed herds might be most probable to implement multiple-sire-breed systems.

Hybrid Sires and Composites

Simply as there is heterosis for reproductive traits in females, there is likewise heterosis in males for semen quality and quantity, mating capacity, and longevity. Using hybrid sires can exist a relatively simple way to create combinations of traits not available in established breeds. Some seed- stock producers specialize in producing hybrid bulls. For the well-nigh part these combine different types, such every bit British-Continental or British- American. Several brood associations accept registries for hybrids.

Finding a reliable source of suitable hybrid bulls can exist difficult. There is a general feeling that hybrid bulls produce more variable progeny, only some research (peculiarly at the U.S. Meat Animal Research Center in Clay Middle, Nebraska) has challenged this impression, at least for quantitative characteristics such every bit body weight. In that location unremarkably is not every bit much reliable genetic evaluation bachelor for hybrid bulls, although some breed associations include hybrids.

In contempo years in that location has been some interest in a breeding system called composites, which is ofttimes dislocated with creating combination breeds. Equally originally conceived by the U.South. Meat Animal Inquiry Eye, the composite system involved creating hybrids and and so intermating them specifically to maintain every bit much heterosis as possible in succeeding generations. The intent was not to create a new breed. For a more than complete give-and-take of combination breeds and composites, see another publication in this serial,Due east- 0, Texas Adapted Genetic Strategies for Beef Cattle—VI: Creating Breeds.

Distinctions between combination breeds, hybrids, and composites are oftentimes blurred. In many ways they can be used in the aforementioned manner in planning and implementing a convenance system. Tabular array 1 compares the features of convenance systems.

Breeding Systems and Breeding Groups

The choice of a convenance arrangement depends partly on the number of divide breeding groups a producer can or will maintain. If feasible, regardless of the breeding arrangement, the development, convenance and calving of heifers should be conducted in a carve up management group using easy-calving sires.

One Breeding Group

One-breeding-group herds, ranging from those needing just i bull to large herds that crave multiple bulls, accept the following choices of breeding systems:

straightbreeding with either a traditional or combination breed
static terminal cantankerous with purchased straightbred or crossbred females
sire rotation
multiple-sire-brood
composite

Two Breeding Groups

2 groups tin can exist used in these systems:

true two-breed rotation (or rotation of two composites or hybrids)
straightbreeding (of traditional or combination breeds) in one group to produce females for a two-breed terminal cross in another group
sire rotation, multiple-sire-breed, or composite in one group to produce replacement females for a terminal cantankerous in another group
purchase of straightbred females for creation of F1 replacements in one group to exist used in a terminal cantankerous in some other group

Three Convenance Groups

Three groups can be used in these systems:

true 3-brood rotation
true two-brood rotation (or rotation of two composites or hybrids) in two groups to produce replacement females for a final cross in a third grouping
consummate terminal, with straightbred females produced in one group to be used for creating F1 females in a second group to exist used for terminal crossing in a 3rd group

Multiple breeding groups are more complex to manage. And, each group in a multi-group crossbreeding arrangement has a dissimilar breed composition, which can reduce marketing flexibility because fewer similar calves are produced. Also, some brood combinations may be less valuable than others. Counterbalance these possible disadvantages against any expected economic do good before implementing systems that require multiple breeding groups.

Efficiencies of Breeding Systems

A standard measure of efficiency of cow-calf production is pounds of dogie weaned per bred moo-cow, which combines fertility, livability, and calf weaning weight. Using this measure, the U.S. Meat Animal Research Center compared brood- ing systems. The footing for comparing was the straightbreeding of traditional breeds, which do not have whatsoever retained heterosis.

Continuous crossbreeding systems requiring but a unmarried breeding grouping can increase efficiency by ten to 15 per centum. Crossbreeding systems using multiple breeding groups, or three- breed terminal crossing in i group using introduced females, tin can increment efficiency past 15 to 30 percent. These estimates are for systems using British and Continental breeds in temperate environments. In harsh tropical or subtropical environments, including types native to these locales, peculiarly Bos indicus, can be even more than efficient considering animals have more heterosis and greater adaptability. These are meaning advantages.

In choosing a breeding system for commercial beefiness cow herds, consider the major factors that affect production efficiency and financial return, including:

number of animals bachelor to market,
average pounds per creature marketed,
average cost per pound, and
total price of production.

Production efficiency and fiscal return are commonly greatest when these factors are balanced, and non when one gene dominates to the exclusion of the others.

Summary

After choosing a breeding system, producers should make up one's mind what breeds and individuals within breeds fit their climate, forage, general management practices, and market place. For a discussion of breeds, run into E-190, Texas Adapted Genetic Strategies for Beef Cattle—V: Type and Breed Characteristics and Uses and Eastward-191, Texas Adapted Genetic Strategies for Beef Cattle—VII:
Sire Types for Commercial Herds. For information on selecting private animals, meet E-164, Texas Adjusted Genetic Strategies for Beef Cattle—VIII: Expected Progeny Deviation (EPD).

Regardless of the size of the cow herd, the apply of single breeding groups is past far the nigh common practice in Texas. Therefore, the prevailing breeding systems are straightbreeding (of both traditional and combination breeds) and purchasing replacement females for a terminal cross, with some implementation of sire rotations or concurrent use of multiple breeds of sire.

When choosing a breeding system, give conscientious thought to the entire procedure. Practice non commence on the commencement phase of a organization without understanding and planning for subsequent stages. A system that works well for one producer or ane set of product and market place atmospheric condition might be unsuitable for another producer or different conditions.

For Farther Information

To obtain other publications in this Texas Adjusted Genetics Strategies for Beef Cattle series, contact your canton Extension office or visit http://AgriLifeBookstore.org or the
Texas A&M Creature Science Extension website
http://beef.tamu.edu.

Download a printer-friendly version of this publication: Texas Adapted Genetic Strategies for Beef Cattle IV: Convenance Systems

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Source: https://agrilifeextension.tamu.edu/library/ranching/texas-adapted-genetic-strategies-for-beef-cattle-iv-breeding-systems/