E-190 3/09 Texas Adapted Genetic Strategies for Beef Cattle V: Type and Breed Characteristics and Uses A 1700s painting of the foundation cow of one of the first cattle breeds. Courtesy of Michigan State University Animal Science Department. Stephen P. Hammack* he subject of breeds intrigues most beef cattle sphere. The Bos taurus in the United States originated in producers. However, breeds are only part of a ge- the British Isles and western continental Europe. The Bos netic strategy that should include: indicus arose in south central Asia. T• Matching applicable performance or functional There are some intermediates containing both Bos levels to environmental, management, and taurus and Bos indicus. Some intermediates created in the marketing conditions United States, particularly in Texas, are commonly re- • Choosing a breeding system, either continuous ferred to as American breeds, which will be discussed later. (in which replacement females are produced Although it has no strict definition, a breed can be within the herd) or terminal (in which replace- described as animals of common origin with certain dis- ments are introduced externally) tinguishing characteristics that are passed from parent • Selecting genetic types, breeds within types, and individuals within breeds that are compat- *Professor and Extension Beef Cattle Specialist–Emeritus, The Texas A&M System ible with the performance level needed and breeding system chosen. Genetic classifications and breeds Cattle can be divided into two basic classifications, Bos taurus (non-humped) and Bos indicus (humped, also called Zebu). Cattle are not native to the western hemi- to offspring. Breed characteristics result from To characterize milking potential accurately, both natural selection and from that imposed it should be evaluated relative to body size. by people. Higher-milking females need more nutrients Currently, more than 75 breeds can be reg- for body maintenance and require higher-quali- istered in the United States. For a discussion of ty diets, even when not lactating. Again, consult breed development, see another publication in E-188, Texas Adapted Genetic Strategies for Beef this series, E-180, Texas Adapted Genetic Strate- Cattle—III: Body Size and Milking Level. gies for Beef Cattle—VI: Creating Breeds and Age at puberty Composites. Age at puberty relates to body size, milking Most breeds have registry associations that potential, and genetic classification. Smaller record ancestry, define and document char- cows and higher milking types usually mature acteristics, and promote the breed. In this earlier, whereas Bos indicus mature relatively publication, estimates of functional traits or late. Although higher milking females, even characteristics are based on estimates of breed large ones, often reach puberty and conceive averages, but individuals can vary considerably when relatively young, subsequent fertility can within breeds. suffer because they may become thin after Functional traits or characteristics beginning lactation. While Bos indicus types reach puberty relatively late, their productive The major functional traits important in life is usually longer. Texas beef production include body size, milk- ing potential, age at puberty, hot climate adapt- Hot climate/tropical adaptability ability, fleshing ability, muscle expression, cut- Adaptability to hot climates is highest in ability, and marbling. cattle with Bos indicus inheritance, but some Bos taurus are reasonably heat tolerant. Ani- Body size mals with lighter colored, short hair coats and Body size is best evaluated as weight at a stat- dark skin are best adapted. ed level of condition or body fatness. Although High humidity intensifies the effects of heat, there are exceptions, weight at all ages tends to especially because hot, humid climates often add be positively related—cattle heavier at birth tend the stresses of parasites and low-quality forage. to be heavier throughout life. Genetically larger Heat with humidity stresses cattle that fail to animals usually gain weight faster, and weight shed long, thick hair coats, particularly dark- and nutritional requirements for body mainte- colored ones. As might be expected, animals nance are closely related. tolerant to hot climates are less adapted to cold. Size is discussed in Extension publication E-188, Texas Adapted Genetic Strategies for Fleshing ability Beef Cattle—III: Body Size and Milking Level. Fleshing ability is the body’s capacity to Frame score, an objective measure of skeletal fatten and retain fat. Fleshing ability tends to dimension used to estimate current and future drop with increases in genetic body size, body size, is discussed in Extension publication maintenance requirements relative to size, E-192, Texas Adapted Genetic Strategies for Beef milking level, and inherent muscularity. Cattle—X: Frame Score and Weight. Animals poorly adapted to their environment An important inconsistency occurs in Bos generally are low in fleshing ability. indicus in body size relationships. Calves from Bos indicus often flesh more easily than other dams containing Bos indicus inheritance are types on low-quality forage and roughage. relatively small at birth, usually resulting in few Easy-fleshing cattle tolerate periods of nutri- difficulties in calving. However, calves by Bos tional energy deficiency more easily and, indicus sires out of Bos taurus dams often are therefore, may reproduce more consistently, but relatively large, so calving may be more difficult. they also over fatten more readily in the feed- yard unless properly managed. Milking potential Milking potential is the genetic capability to Muscle expression produce milk. This is not the actual volume of Muscle expression is inherent muscularity, milk produced, which also is influenced by the independent of other body tissues. Muscling is cow’s nutrition and the calf’s growth potential the second most important factor in cutability. and nursing pressure. Heavy-muscled types often are low in fleshing 2 ability, so reproductive efficiency may be • British Beef—British-originated breeds reduced. and combinations among those breeds used for beef production only. Cutability • Continental Beef—Continental European Cutability, or the percentage of lean, is breeds and derivatives developed exclu- usually evaluated in beef carcasses as USDA sively for beef production. These are part Yield Grade. Cutability depends on relative of what are sometimes called “exotics.” amounts of fat (which varies greatly), muscle, • Continental Dual Purpose—Breeds se- and bone (which varies least). lected for both beef and dairy production When genetic types or breeds are compared in their native areas, mostly Continental for differences in cutability, it is assumed that Europe, and combinations of beef and the breeds have similar nutrition levels. But dairy breeds. Dual Purpose breeds are inherent cutability differences can be readily used only for beef in the United States. altered by varying nutrition to achieve similar They are the other part of “exotics.” degrees of fatness. • Dairy—Originating in western Conti- Marbling nental Europe or the British Isles and Marbling, or intramuscular fat, is the primary selected in the United States for dairy factor determining USDA Quality Grade, an purposes only, with beef production oc- indicator of the palatability factors of tenderness, curring secondarily. juiciness, and flavor. Marbling increases with age • Bos indicus—Of pure or very high per- up to physiological maturity and generally is centage Bos indicus background and used higher in earlier maturing and higher milking only for beef production. types. Feeding high-energy rations starting early • American—Includes beef breeds created in life for extended periods generally increases in the United States from combinations marbling. of about one-fourth to one-half tropical- adapted inheritance, typically the Bos indi- Bos indicus and most heavy-muscled, low- cus-derived Brahman, with the remainder milking types have relatively low marbling. usually consisting of British Beef breed(s), Because marbling relates somewhat to body although Continental Beef or Continental fatness, especially in comparing breeds or types, Dual Purpose may also be found. there is usually a trade-off between Yield Grade • Specialty—Includes breeds that cannot be and Quality Grade. As one improves, the other placed logically in any of these groups, of- tends to decline. For a discussion of carcass ten characterized by particular emphasis genetic considerations, see E-165, Texas Adapted on certain traits. Genetic Strategies for Beef Cattle—IX: Selection for Carcass Merit. Matching functional levels An important consideration in determining optimum functional levels is that types of cattle to production criteria may differ in relative performance under varying Climate and nutrition are key variables conditions. For a discussion of this topic, see affecting the locations where differing types E-187, Texas Adapted Genetic Strategies for Beef and breeds can be produced. Production suffers Cattle—II: Genetic-Environmental Interaction. when cattle are not adapted to climatic condi- tions. In hot, humid climates, cattle benefit Breeds and functional types from some Bos indicus or other tropical-adapt- ed genetics. Table 1 lists the characteristics of the major breeds of cattle in Texas—those most numerous Table 2 shows the effects of nutrition on or most familiar in the state—by estimates of optimum levels of three primary production