Life Sciences Commons^™

A Simple Method For Freezing Bovine Embryos, Sherrill E. Echternkamp, Donald Elliott

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Deep freezing (cryopreservation) of bovine embryos provides an efficient economical method for storing embryos until suitable recipient cows (surrogate mothers) are available, or for transporting embryos to recipient cows at a distant location (e.g., exportation or importation of embryos between continents or geographic areas). Pregnancy rates achieved with frozen bovine embryos have increased steadily during the past five years and are approaching those obtained with fresh bovine embryos. However, acceptable pregnancy rates are only achieved when Grades 1 and 2 quality (excellent and good quality) embryos are frozen; survivability of Grade 3 (fair quality) embryos is considerably higher if the …

Beef Ribeye Muscle Glycogen And Color Response As Affected By Dietary Regimen And Postmortem Electrical Stimulation In Young Bulls, Mark R. Miller, H. Russell Cross, Marietta J. Buyck, John D. Crouse

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Utilization of the intact male by the beef industry has been the focus of much research in recent years. Advantages of bulls compared to steers in production efficiency, performance, and carcass leanness have been well documented. Disadvantages include aggressive behavior, darker postmortem muscle color, lower USDA quality grades, and, often, less tender meat. The superior production performance of bulls has not been utilized by the meat and livestock industries partly because of these disadvantages.

Postmortem muscle color is associated with energy content of the diet, antemortem muscle glycogen content, postmortem muscle pH decline, and ultimate pH, all of which are …

Factors Associated With Tenderness Of Three Beef Muscles, Mohammad Koohmaraie, Steven C. Seideman, John D. Crouse

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Tenderness is the prominent quality determinant and probably the most important sensory characteristic of beef steak and roast meat. Currently postmortem aging (storage of carcass at refrigerated temperatures for 8 to 14 days) appears to be the best method for producing tender meat. Although the improvement in meat tenderness as a result of postmortem aging is measurable both subjectively and objectively, the exact mechanism responsible for this improvement in tenderness is unknown.

It is well known that different muscles within the same carcass react differently to postmortem storage; for example, tenderloin is tender to begin with and does not improve …

Fetal Development In Cows With Multiple Fetuses, Sherrill E. Echternkamp

Roman L. Hruska U.S. Meat Animal Research Center: Reports

About 60% of the nutrient requirements for beef production in the U.S. are for maintenance of the breeding herd. In addition, the bovine female only produces about .7 of her body wt per yr in progeny wt. Thus, increasing the reproductive rate in beef cattle would have a major economic benefit. Although most bovine females are capable of gestating two calves, the natural frequency of twin births is low, ranging from less than .5% to 4% of the calvings, depending upon the breed of cattle. Several studies have indicated that the frequency of multiple births in cattle can be increased …

Growth And Carcass Traits Of Heifers As Affected By Hormonal Treatment, John D. Crouse, Bruce D. Schanbacher, H. Russell Cross, Steven C. Seideman, Stephen B. Smith

Roman L. Hruska U.S. Meat Animal Research Center: Reports

The beef industry traditionally has discriminated against young heifers in the marketplace when compared with steers. Price discrimination was probably the result of sex effects on fat partitioning and distribution. Also, steers have been observed to be more efficient than heifers in the conversion of feed to carcass weight.

Both testes and ovaries secrete steroids that influence performance traits of cattle. Testosterone appears to stimulate rate of gain and efficiency of feed conversion in the male. Efficiencies of conversion of feed to live animal weight gains have been less in spayed feedlot heifers than in intact heifers.

It has been …

Germ Plasm Evaluation In Cattle, Larry D. Cundiff, Robert M. Koch, Keith E. Gregory

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Breed differences in performance characteristics are an important genetic resource for improving efficiency of beef production. Diverse breeds are required to exploit heterosis and complementarity through crossbreeding and to match genetic potential with diverse market requirements and climatic zone-feed resource situations.. Genetic variation among breeds can be used to provide an array of beef products that differ widely in fat and caloric content. Diverse feed resources will continue to be used for cow herds among and within different geographical regions of the U.S. Thus, it is important to characterize breeds of cattle representing different biological types for a wide spectrum …

Germ Plasm Utilization In Beef Cattle, Keith E. Gregory, Larry V. Cundiff, Robert M. Koch

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Heterosis achieved through well-organized crossbreeding systems can be used to increase weight of calf weaned per cow exposed to breeding by about 20%. Comprehensive programs of breed characterization have revealed large differences among breeds for most biological traits of economic importance.

Ahigh percentage of beef cattle in the U.S.and globally are in herds too small to use well organized crossbreeding systems on a self-contained basis. Further, there is wide fluctuation in breed composition between generations in rotational crossbreeding systems. Thus, there is need for experimental evaluation of the potential of composite populations as an alternative, or, as a supplement to …

Investigation Of The Major Histocompatibility Complex In Cattle And Its Association With Economically Important Traits, Noelle E. Muggli, Michael J. Stear, Roger T. Stone

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Efficiency of animal production could be increased by reducing losses due to diseases. Therefore, disease resistance is an obvious trait to include in a selection program. However, how to incorporate this trait into the program is a difficult question. While it has been experimentally shown that selection for resistance against specific diseases is effective, it would be impossible to select for resistance to all potential diseases. Also, selection studies in mice show that increasing resistance to one disease can result in increased susceptibility to other diseases. This may be because antagonistic relationships exist among the mechanisms of the immune system. …

Mating And Grazing Behavior Of Low And High Serving Capacity Beef Bulls During Average And Heavy Mating Loads At Pasture, Garth W. Boyd, Donald D. Lunstra, Larry R. Corah

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Although artificial insemination is widely used in dairy cattle, it has found only limited application in beef cattle. Use of bulls in natural mating programs accounts for over 90% of the pregnancies achieved each year in the U.S. beef cattle industry, and a large percentage of the beef bulls used for natural mating are purchased as yearlings. Many of these yearling bulls undergo a breeding soundness examination prior to sale or the breeding season. This involves visual and manual examination of the genital system as well as assessment of semen, which is usually collected by electroejaculation. However, sex drive and …

Nutritional Value Of Anaerobically Fermented Beef Cattle Wastes As A Feed Ingredient For Livestock, Ronald L. Prior, Andrew G. Hashimoto, John D. Crouse

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Waste is produced in large quantities in cattle feedlots, and this is a potential environmental pollutant. Recycling of feedlot waste as livestock feed has been investigated extensively as one means of lowering the disposable waste load. Refeeding fresh manure will only partially alleviate waste disposal problems. In one study, only about one-half of the manure collected daily could be refed, and the remainder was discarded.

Currently, there is increased interest in the development of a microbial process for recycling and utilizing feedlot wastes. Commercial digestors are in operation. In some of these systems, the potential exists for capturing methane as …

Serum Concentrations Of Luteinizing Hormone, Testosterone, And Thyroid Hormones In Low And High Serving Capacity Beef Bulls, Garth W. Boyd, Donald D. Lunstra, Bruce D. Schanbacher, Larry R. Corah

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Adequate sex drive in bulls is essential for natural mating to be successful. Expression of male sexual behavior and mating ability during sexual maturation is dependent upon attaining adequate testicular development and blood levels of luteinizing hormone (LH) and testosterone (T). Several researchers have investigated the relationship between levels of sexual behavior in postpubertal bulls and blood concentrations of LH and T. Some of these researchers reported a positive relationship between T and serving capacity (SC), and others found that individual differences in sexual performance could not be predicted based on circulating levels of T or LH. In those studies, …

Relationship Of Growth Hormone, Prolactin, And Thyrotropin Secretion To Individual And Progeny Performance Of Hereford Bulls, Danny L. Ohlson, Robert M. Koch, John Klindt, Steven L. Davis

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Evidence from several studies has supported a predictive relationship between measures of somatotropic hormones and genetically determined growth potential in domestic ruminants. In these studies, blood concentrations of hormones associated with growth were generally higher in lines or breeds with greater growth potential. However, no significant positive correlations between measures of hormone secretion and measures of growth in individual animals were observed.

The present study further assesses the association between growth potential, growth rate, and secretion of growth hormone (GH), prolactin (PRL), and thyrotropin (TSH) using bulls of two Hereford lines that differ in growth rate as a result of …

Twinning And Efficiency Of Beef Production, Gordon E. Dickerson, Pedro Guerra-Martinez, Gary Anderson, Ronnie D. Green

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Twinning is relatively rare in most breeds of beef cattle - less than 1 to 2% of calvings and less frequent for immature females. Twin calving has generally been considered undesirable because of the smaller calf size, higher calf mortality, infertility of females born twin with a male, more retained placentas, and possible delayed rebreeding experienced with twin calvings when observed under feeding and management that is geared to single calving. However, costs for just maintaining the breeding herd account for over one-half of the total costs of beef production. Thus genetic twinning may offer a means of increasing total …

Roman L. Hruska U.S. Meat Animal Research Center: Overview, Robert R. Oltjen

Roman L. Hruska U.S. Meat Animal Research Center: Reports

The U.S. Meat Animal Research Center (U.S. Meat Animal Research Center) was authorized by Congress on June 16, 1964, thereby creating a single facility that provides an unusual opportunity for making major contributions to the solution of problems facing the U.S. livestock industry. Development of the 35,000-acre facility started in the spring of 1966and is continuing at the present time. Phase I construction, consisting of an office-laboratory building for intensive investigations, was completed in January 1971.These facilities provide a physical plant for 42 scientists and about 200 support personnel. Phase II construction, consisting of the Meats Research Laboratory and the …

Zinc And Protein Levels In Finishing Diets Of Medium-And Large-Frame Steers, Wilson G. Pond, Robert R. Oldjen

Roman L. Hruska U.S. Meat Animal Research Center: Reports

The National Research Council lists the daily protein requirements of medium-frame and large-frame steers weighing 770 lb and gaining 2.2 lb daily as 1.7 and 1.8 lb, respectively; comparable values at 1,100 lb are 1.9 and 2.1 lb. These amounts of protein are expected to be provided for medium-frame steers weighing 880 lb and gaining weight at 2.2 lb daily by a diet containing 10.3% protein; the corresponding value for large-frame steers is 10.2% protein. Medium- and large-frame steers weighing 1,100 lb and gaining weight at 2.2 lb daily require 9.5% protein in the diet.

The zinc requirement of steers …

A Voice-Input And Knowledge-Based Expert System For Grading Carcass Beef, Yud-Ren Chen

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Assessing meat yield and quality in carcasses is important for exporting meat and for the domestic consumer. The U.S. livestock and meat industries depend heavily on USDA to provide the rating of their meat for marketing. There is also a trend in the U.S. meat industry to process meat closer to the site of slaughter because of increasing transportation and energy costs. Only the edible portion of the carcass will leave the slaughter plant. These trends will increase the volume and demand for more consistent, equitable, and timely methods for grading meat.

Since the USDA meat grading system was first …

Anabolic Steroids And Implants In Feedlot Steers, Bruce B. Schanbacher, John Brethour

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Profit from livestock production is affected by daily liveweight gain, cost of gain, and feed conversion efficiency. Young beef calves are recognized as suitable converters of forages and grains into wholesome red meat, but constraints to maximum production efficiency are recognized. While their growth and development are often discussed in light of genetic potential, nutritional requirements, and environmental constraints, administration of anabolic agents to maximize their gains is a common practice. Several implants are available to the cattle industry as growth promotants; some of these contain steroids of gonadal origin while others are nonsteroidal.

Steroids secreted by the testes are …

Beef Facilities And Management At U.S. Meat Animal Research Center, Margaret S. Mcalhany, W. Gordon Hays, Gary S. Ross

Roman L. Hruska U.S. Meat Animal Research Center: Reports

The Cattle Operations Unit functions as a support service to the research scientists and maintains the animal populations necessary for our livestock research. Indirectly, this also involves responsible land management and herd health procedures. All the facilities and procedures employed in maintaining the extensive cattle herd are determined by research needs. Consequently, while providing a function sometimes indirectly related to research, the operations unit is necessary to provide adequate feedstuffs and healthy animals for research studies.

Bison, Hereford, And Brahman Growth And Carcass Characteristics, Robert M. Koch, John D. Crouse, Steven C. Seideman

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Bison, Hereford, and Brahman represent three species of the bovine family that evolved under different environmental conditions. There has been much interest in these species and hybrids among them to find animal types that are better adapted to the climatic conditions of the U.S. northern temperate zones down to the subtropical areas. There has been considerable research on growth and carcass characteristics of crosses among British, European, and Brahman cattle types, such as studies at U.S. Meat Animal Research Center. However, there is little experimental documentation of the growth and carcass merit of Bison or their crosses. The three species …

Breed And Heterosis Utilization In Rotational And Composite Crosses, Gary L. Bennett, Michael D. Macneil

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Rotational crossbreeding systems breed heifers sired by one breed to bulls from another breed. Heifer offspring are then bred to the next breed in the rotation, etc. Composite systems result in a "new" breed consisting of fixed proportions of "old" breeds. Both systems produce their own replacement heifers rather than requiring the purchase of F₁ heifers or special matings. Both systems have potential advantages for producers of slaughter beef because a high level of heterosis (hybrid vigor) is present in cows and calves. High levels of heterosis increase efficiency and reduce the cost of producing beef.

The level of …

Current Concepts For Understanding Ovarian Follicular Growth And Function In Cattle, Leon J. Spicer, Sherrill E. Echternkamp

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Ovarian follicular development in cattle during either the estrous cycle or postpartum anestrus is not presently well understood. Although several investigators have suggested that follicular development is continuous, the notion that follicular growth occurs in waves still persists. A better understanding of bovine folliculogenesis is required to solve beef production problems such as prolonged postpartum infertility and variable responses to superovulation and estrous synchronization treatments. Therefore, research was conducted at U.S. Meat Animal Research Centerand results compared with earlier studies to explain follicular growth and function in cattle during postpartum anestrus.

Demasculinization Of Beef Bulls By Lh Immunization, Bruce D. Schanbacher

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Intact bull calves grow more rapidly in the feedlot than do their castrate counterparts but are generally less acceptable to the packer because of excess masculinity and insufficient intramuscular and external fat for postmortem handling and storage. Steers, on the other hand, are less efficient and yield less lean meat than bulls. Therefore, it was envisaged that reducing the masculinity of bulls by a noninvasive, nonsurgical procedure might yield a more suitable market animal.

Effect Of Season And Relocation On Reproductive Competence In Brahman And Hereford Bulls, Robert W. Godfrey, Ronald D. Randel, Charles R. Long, Donald D. Lunstra, Thomas G. Jenkins, James Berardinelli

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Careful selection of a breed or breeds and emphasis upon selection pressure within a breed can increase productivity of a beef cattle herd. Furthermore, productivity within a herd may be effectively increased by utilizing crossbreeding programs. Crossing genetically diverse breeds permits combination of important traits and taking advantage of hybrid vigor. Many crossbreeding programs currently in use involve crosses between Bos indicus and Bos taurus cattle. One of the more commonly used Bos indicus breeds is the American Brahman. Use of the American Brahman in crossbreeding programs throughout the U.S. would increase demand for bulls of this breed.

Brahman cattle …

Effects Of Dietary Energy Density On Carcass Composition And Beef Palatability Characteristics, Gary L. Bennett

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Currently there is increased emphasis on production of lean beef with desirable palatability characteristics. Changes in both the type of animal produced and the feeding and management of these animals may be needed to efficiently produce this product. One change in feeding that could be made is the energy density of the feed, measured as megacalories of metabolizable energy per pound (Mcal ME/lb). At low energy densities, the amount of feed that can be consumed limits the animal's intake of metabolizable energy.

Over the past two decades, several experiments at U.S. Meat Animal Research Center have examined a number of …

Follicle And Oocyte Relationships During Superovulation In The Heifer, Thomas H. Wise, Ralph R. Maurer

Roman L. Hruska U.S. Meat Animal Research Center: Reports

As the female cow matures, the majority of her follicles become atretic and are lost as a store house of the female gamete (oocyte). Emphasis on in vitro fertilization to maximize the utilization of superior animals for transplant of frozen embryos is considerably limited by the number of viable mature oocytes that can be collected. Understanding the biochemical environment required to produce maximum numbers of mature, fertilizable oocytes is a prime requirement to utilize this technology in increasing meat animal production and efficiency.

The goal of these studies was to characterize the endocrine and biochemical events associated with follicle and …

Breeding For Lean Beef (Germ Plasm Evaluation Program), Larry V. Cundiff, Michael E. Dikeman, R. M. Koch, John D. Crouse, Keith E. Gregory

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Historically, when steers were finished on pasture, ability to finish at a young age was desirable, particularly when market requirements for fatness were great. However, ability to fatten became a handicap as we shifted to increased use of concentrate feeds in diets of growing-finishing cattle. Consequently, yield grades were added to the USDA grading system to reflect variation in carcass value associated with differences in yield of retail product. Recently, consumer pressure to reduce caloric and fat content of beef and other red meats has intensified because coronary heart disease is believed to be associated with elevated blood-cholesterol levels. Cholesterol …

Heterosis, Breed Maternal, And Breed Direct Effects In Red Poll And Hereford Cattle, Keith E. Gregory, Delwyn D. Dearborn, Donald D. Lunstra, Larry V. Cundiff, Robert M. Koch

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Breed differences, heterosis, and reciprocal cross differences from beef cattle crossbreeding experiments have been summarized in prior reports from U.S. Meat Animal Research Center and reports from other research stations.

However, there have been only limited reports to characterize the Red Poll breed relative to other breeds. This report summarizes results from an experiment where reciprocal crosses and straightbreds were produced to estimate heterosis, breed maternal effects, and breed effects for growth rate of the Red Poll and Hereford breeds.

Individual Heterosis Effects On Mature Size And Maternal Heterosis Effects On Preweaing Traits And Postweaning Growth And Carcass Traits, Keith E. Gregory, Delwyn D. Dearborn, Larry V. Cundiff, Robert M. Koch

Roman L. Hruska U.S. Meat Animal Research Center: Reports

The Brown Swiss, Red Poll, Hereford, and Angus breeds and their 12 reciprocal crosses from a four.breed diallel crossing experiment were evaluated for production and carcass characters. Estimates of average heterosis and breed maternal and additive direct effects were reported earlier for preweaning traits, growth rate and puberty in females, growth traits of steers, and carcass traits of steers. This report provides results from the second phase of this experiment for maternal performance data on the females, including estimates of heterosis and breed maternal and additive direct effects on cow size and on preweaning traits, postweaning growth, and carcass traits …

Effect Of Subcutaneous Fat Removal On Beef Tenderness, Mohammad Koohmaraie, Steven C. Seideman, John D. Crouse

Roman L. Hruska U.S. Meat Animal Research Center: Reports

It is now widely recognized that consumers do not accept meat with excessive quantities of fat. To make cuts of meat acceptable to the consumer, packers and retailers are forced to trim much of the subcutaneous fat. If this consumer demand persists, the meat industry will be forced to change its production system to produce leaner cattle.

Subcutaneous fat cover is thought to act as an insulator, retarding rapid temperature decline and consequently preventing cold-induced toughness. Cold-induced toughening is a phenomenon observed when prerigor excised muscles are exposed to cold ( < 50° F) temperatures. However, there is no conclusive evidence that cold-induced toughening actually happens under current meat industry practices of slaughtering and carcass handling. The objectives of these experiments were to examine the effect of the removal of subcutaneous fat and high temperature conditioning on beef tenderness. High temperature conditioning (HTC) - storage of carcasses at high temperatures (e.g. 78° F) for 3 to 6 hr after slaughter - was included to attempt prevention of cold-induced toughness in defatted carcasses.

Inheritance Of Active And Passive Immunity In Beef Calves, Noelle E. Muggli, Bill D. Hohenboken, Larry V. Cundiff, Don E. Mattson

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Disease is caused by successful invasion of pathogenic organisms (e.g., viruses, bacteria, parasites). The immune system is responsible for the protection of an individual against these invasions. This system is complex, with interconnective parts composed of many stimulators, inhibitors, effectors, and consequences. Immunity that is dependent upon antibodies or immunoglobulins can be either active or passive in origin. In active immunity, the body produces protecting antibodies in response to a naturally occurring infection or to vaccination against a pathogenic organism. Vaccination will prime the animal's immune system for a faster and more effective response to later infections. In passive immunity, …