Life Sciences Commons^™

Beef Facilities And Management At U.S. Meat Animal Research Center, 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.

Can Cattle Be Litter Bearing? Uterine Capacity In Cattle., Sherrill E. Echternkamp

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

With few exceptions, the bovine female produces one ovum per estrous cycle, and consequently one offspring per year. Thus,the reproductive rate of cattle is low in comparison to other meat-producing animals, birds and fish. Studies at the University of Wisconsin in the early 1950's indicated that the frequency of twin ovulations was 1O-fold greater than the frequency of twin births. However, a recent evaluation of ovulation rate in the U.S. Meat Animal Research Center twinner herd indicated that about 50% of the twin ovulations resulted in twin births. With a twinning frequency of 25% in this population, it is suggested …

Biological Efficiency Differences Among Bos Taurus X Bos Taurus And Bos Indicus X Bos Taurus F1-Cross Cows, Ronnie D. Green, Larry V. Cundiff, Gordon E. Dickerson, Thomas G. Jenkins

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

Matching germplasm to resources through designed crossbreeding programs can contribute to optimum beef production efficiency. This is particularly true in light of the wide diversity of environmental conditions encountered by beef producers in the U.S. This approach requires considerable knowledge about genetic diversity among breeds in components of performance and furthermore how those components interact to influence life-cycle efficiency in the production setting. It was largely this identified need, coupled with the importation of a number of new breeds from continental Europe, that gave impetus for the establishment of the Germplasm Evaluation (GPE) Program. In Cycles I and II of …

Characterizing Stress In Feeder Cattle, G. Leroy Hahn, John A. Nienaber

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

During the period August 6 to 10, 1992, a heat wave moved through central and eastern Nebraska. Maximum air temperatures were in the 90 to 95°F range, generally not considered to be extreme during the summer season. However, during this particular episode, the accompanying humidity was higher than normal (50 to 70% during the hottest portions of the day), with light to moderate winds except on August 8 when the wind was fairly strong. The relatively cool preceding summer weather had not adequately conditioned livestock to high levels of heat stress. As a result, several hundred feedlot cattle died in …

Effect Of Marbling On Variation And Change In Beef Tenderness In Bos Taurus And Bos Indicus Crosses, Robert M. Koch, John D. Crouse, Michael E. Dikeman, Larry V. Cundiff, Keith E. Gregory

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

Today's diet conscious consumers continue to desire flavorful, tender meat, but increasingly avoid excess fat. Differences in USDA quality grades within similar aged cattle are determined primarily by differences in marbling scores which tend to be associated with overall fatness in beef carcasses. Previous studies (Cundiff et al., 1988) demonstrated an antagonism between lean yield in carcasses and degree of marbling associated with higher quality grades. Breeds that rank highest for retail product percentage rank lowest for marbling. High negative genetic correlations have been found within breeds between marbling and retail product percentage. Thus, only limited opportunity exists for genetically …

Feedlot And Carcass Characteristics Of Heifers: Effect Of Ovariectomy And Ovariectomy With Ovarian Autograft, John M. Klindt, John D. Crouse

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

Heifers as beef animals traditionally have been discriminated against in the marketplace. This discrimination is the result of ovarian secretions acting on performance and nutrient partitioning, as well as the possibility of pregnancies. The actions of ovarian secretions can be through their differentiational effects, permanent effects on the development and physiology of the individual, and through activational effects, temporary effects expressed only when the activating agent is present. Expression of heat or estrual activity is an example of an activational effect. The fatter carcasses which heifers generally produce is an example of a differentiational effect. Not only do heifers produce …

Fiber Degrading Microorganisms From Bison, Cattle-Bison Hybrids And Cattle., Vincent H. Varel, Burk A. Dehority

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

The limiting factor in forage plants which prevents more complete degradation by ruminants is the fiber component. Sometimes called lignocellulose, this fraction is primarily composed of cellulose, hemicellulose, and lignin. Forages are normally high in lignocellulose when compared to cereal grains, therefore they are lower in digestibility, which in turn results in reduced efficiency of animal production. Studies have shown that a small increase in forage digestibility, such as 7 to 12%, can result in increases of 30 to 40% in animal gain. These numbers provide a substantial incentive to further study the factors which limit the degradation of forage …

Genotype-Environment Interactions For Reproduction And Maternal Performance Of Bos Indicus And Bos Taurus Crosses In Nebraska And Florida, Larry V. Cundiff, Timothy A. Olsen, K. Euclides Filho, M. Kroger, W. T. Butts, Keith E. Gregory

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

In the U.S., cattle of diverse breeds and crosses are maintained in diverse climatic environments ranging from the temperate-continental conditions of the North Central region, characterized by wide fluctuations in temperate from winter to summer, to subtropical conditions of the Southeastern region, characterized by relatively moderate winter temperatures but high temperatures and humidity in the summer mo. The genetic range is spanned by Bos indicus (humped cattle) breeds, that originally evolved under tropical conditions of India and Pakistan, and by Bos taurus (nonhumped) breeds, that originally evolved under temperate conditions of continental Europe and the British Isles. The present experiment …

Gene Mapping In Cattle, Craig W. Beattie, Roger T. Stone, Michael D. Bishop, Sara L. F. Sunden, John W. Keele, Steven M. Kappes

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

Over the last decade, progress in molecular biologic techniques has brought the mapping of genes within the human and mouse genomes to a point where information on the location of groups of genes and additional anonymous, but unique, bits of DNA (markers) within their respective genomes can be brought to bear in developing a bovine genomic map. This is possible because of the conservation of genes, particularly those concerned with regulating important functions, between species into syntenic (single chromosome) groups.

Investment in the development of a bovine map is important for several reasons. While continued selection of desirable traits by …

Hormone Profiles In Cattle Selected For Twin Ovulations And Births, Sherrill E. Echternkamp, Leon J. Spicer, Keith E. Gregory

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

Follicle stimulating hormone (FSH) is secreted into the blood circulatory system by the pituitary and as the name implies stimulates growth and development of follicles within the female ovary. Thus, the administration of exogenous FSH or FSH-like substances (e.g., pregnant mare's serum gonadotropin, PMSG) to cattle has been used for the induction of multiple ovulations and, subsequently, twin or multiple births. These same substances have been used extensively for the induction of superovulation in embryo donor females. Consequently, it was speculated that cows producing twin births naturally from the spontaneous ovulation of multiple ovarian follicles would have higher circulating concentrations …

Immunization Against Inhibin Increases Sperm Production In Young Beef Bulls, Donald D. Lunstra, Terry L. Martin, Gary L. Williams, James J. Ireland

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

The specific biological mechanisms that control pubertal development, testicular growth and onset of sperm production in the beef bull have not been well defined. It is known that two protein hormones (the gonadotropins, LH and FSH) produced by the pituitary stimulate testicular growth, cause an increase in numbers of testicular receptors for LH and FSH, and stimulate production of steroid hormones by the testes. Researchers have shown that the patterns of LH and FSH secretion diverge during the peripubertal period in several species, including the bull. While LH increases during the peripubertal period of development in the bull, FSH exhibits …

Mortality And Cold Tolerance Of Calves With Different Ratios Of Bos Indicus To Bos Taurus Inheritance, Maurie J. Josey, Larry V. Cundiff, Robert M. Koch, Keith E. Gregory, G. Leroy Hahn

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

Results from the Germplasm Evaluation Program (GPE) at the Roman L. Hruska U. S. Meat Animal Research Center (U.S. Meat Animal Research Center) have shown that significant differences exist among cows representing breeds of diverse biological types In such production traits as 200-day weaning wt per cow in the breeding herd. Production of Bos indicus F₁ cross cows (Brahman and Sahiwal sired crosses out of Hereford and Angus dams) was equalled only by F₁ cross cows sired by large size dual purpose breeds (Brown Swiss, Gelbvleh, Simmental, Holstein and Maine Anjou crosses out of Hereford and Angus dams) …

Omasal And Duodenal Nutrient Flow In Steers., Kelly K. Kreikemeier, Gary P. Rupp, Louis J. Perino

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

Feedstuffs are degraded in the rumen, providing energy and nutrients for microbial growth. Volatile fatty acids produced during this process are absorbed and used as an energy source by the animal. The bacteria that are produced and unfermented feed residue flow out of the rumen to the small intestine where further digestion and absorption occurs. Of the total protein flowing to the small intestine, 50 to 90% is microbial protein. It is of high quality, well digested and well used by the animal.

Currently, estimates of the amount of microbial protein synthesized in the rumen vary considerably. We do not …

Puberty Occurs At The Same Testis Size In Both Bos Taurus And Bos Indicus Crossbred Beef Bulls, Donald D. Lunstra, John D. Crouse, Larry V. Cundiff

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

An increasing number of Bos indicus-blood bulls are being used in crossbreeding programs for commercial beef production in the U.S., but there is little information available on pubertal development, sperm production and semen quality for young bulls of this type. Puberty in young Bos taurus bulls has been defined in a variety of ways (e.g., first ability to serve, first sperm production, first ejaculation of motile sperm, etc.), but all of these criteria are costly and labor-intensive to determine. We have shown previously (Lunstra et al., 1978) that, among young Bos taurus beef bulls of various breeds reared in …

Twinning In Cattle, Keith E. Gregory, Sherrill E. Echternkamp, L. Dale Van Vleck, Larry V. Cundiff

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

Rate of reproduction has a major impact on life cycle costs of production of different animal species and upon their competitiveness for different types of production resources. For example, the average beef cow is capable of producing about .7 of her body weight per year in progeny market weight; comparable values are about 8 in pigs, more than 70 in meat chickens and more than 1,000 in catfish. More than 50% of the feed nutrients used by the beef cattle industry of the United States are needed to meet maintenance requirements of reproducing females. The comparable value in meat chickens …

Roman L. Hruska U.S. Meat Animal Research Center (1993): Overview, D. B. Laster

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

The Roman L. Hruska U.S. Meat Animal Research Center (U.S. Meat Animal Research Center) is part of the U.S. Department of Agriculture's Agricultural Research Service. 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 contributions to the solution of problems facing the U.S. livestock industry. The 35,000-acre facility and the otficelaboratory buildings provide a physical plant for about 80 scientists and about 200 support personnel. In addition, the University of Nebraska's Great Plains Veterinary Educational Center (GPVEC) provides a facility for four university faculty …

Beef Research Program Progress Report (1993) No. 4 (Part 1): Table Of Contents

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

ROMAN L. HRUSKA U.S. MEAT ANIMAL RESEARCH CENTER, D.B. Laster .... v

General Interest

Beef facilities and management at U.S. Meat Animal Research Center: W. Gordon Hays and Gary S. Ross .... 1

Genetics and Breeding

Cycle V of the germplasm evaluation (GPE) program in beef cattle: Larry V. Cundiff, Keith E. Gregory, and Robert M. Koch .... 3

Contributions of ovum cytoplasm and uterine environment and postnatal environment to maternal effects in beef cattle: Keith E. Gregory, and Ralph R. Maurer .... 6

Germplasm utilization in beef cattle: Keith E. Gregory, Larry V. Cundiff, Robert M. Koch, and Donald …

Acceleration Of Postmortem Tenderization In Brahman-Cross Beef Carcasses By Calcium Chloride, Mohammad Koohmaraie, Georgianna Whipple, John D. Crouse

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

The recently completed National Tenderness Survey and Beef Quality Audit have clearly demonstrated that variation in beef tenderness at the consumer level is one of the major problems that face the meat industry. Because of this, and since consumers consider tenderness to be the principal component of meat quality, scientists in the Meats Research Unit of U.S. Meat Animal Research Center have placed a special emphasis on understanding factors that determine beef tenderness.

To enhance tenderness, meat is normally aged (as wholesale cuts or carcasses). During this aging period a number of changes occur in the meat which result in …

Bos Indicus Breeding Effects On Muscle Characteristics And Their Relationship With Meat Tenderness, Georgianna Whipple, Mohammad Koohmaraie, Michael E. Dikeman, John D. Crouse, Melvin C. Hunt

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

Variation in meat tenderness that exists among animals may be due to genetics, diet, age, and other factors. Results from the Germplasm Evaluation (GPE) program show that rib eye steaks from many of the Bos indicus breeds of cattle are less tender than steaks from most of the European (Bos taurus) breeds of cattle, although Bas indicus crossbreeding programs are advantageous due to hybrid vigor and insect and heat resistance in subtropical regions. Because consumers consider tenderness to be the principal component of cooked beef quality, it is important to determine the biological factors that regulate meat tenderness. …

Bovine Embryos From Bluetongue Infected Donors Did Not Transmit Virus To Susceptible Recipients, John A. Acree, Sherrill E. Echternkamp, Steve M. Kappes, Gary S. Ross, Albert J. Luedke, James E. Pearson

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

The recent development of methodology for the successful cryopreservation (Le., ultra low temperature freezing) of bovine embryos has expanded the opportunities for international movement of bovine embryos and has facilitated the exchange of germplasm within and among countries. Unfortunately, frozen embryos also provide an excellent vehicle for the distribution of pathogenic agents (e.g., bluetongue virus, foot and mouth disease, etc.) between livestock populations and between countries. Most pathogens that are on the surface of an embryo with an intact zona pellucida (a translucent mucopolysaccharide shell surrounding the embryo) can be removed by washing. The washing procedure consists of subjecting the …

Comparisons Of Bos Indicus And Bos Taurus Inheritance For Carcass Beef Characteristics And Meat Palatability, John D. Crouse, Larry V. Cundiff, Robert M. Koch, Mohammad Koohmaraie, Steve C. Seideman

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

Crossbreeding is used widely to exploit heterosis and additive genetic variation among breeds to improve efficiency of beef production. The economic value of Bos indicus breeds of cattle, primarily Brahman, in crossbreeding programs in subtropical and tropical climates has been well established. In the temperate climatic conditions of U.S. Meat Animal Research Center, productivity of Bos indicus x Bos taurus F₁ crossbred cows has been outstanding for reproduction an matemal performance relative to that of Bos taurus x Bos taurus F₁ cross cows when mated to produce terminal-cross calves by Red Poll or Simmental sires. (Brahman and Sahiwal …

A Calcium Chloride Injection Process To Produce Guaranteed Tender And Calcium Fortified Meat, Tommy L. Wheeler, Mohammad Koohmaraie, John D. Crouse

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

The recently completed National Beef Tenderness Survey revealed that current beef production practices result in considerable variation in meat tenderness and an unacceptable percentage of tough meat, particularly round and chuck cuts. It has been known for several years that meat from Bos indicus cattle was tougher than meat from Bos taurus cattle and that Bos indicus-influenced cattle make up approximately 25% of the beef cattle in the U.S. In addition, as the beef industry moves towards leaner beef, many production systems that decrease fatness also result in decreased tenderness (i.e., bulls vs steers, forage feeding, growth promotants). Furthermore, …

Cycle V Of The Germplasm Evaluation (Gpe) Program In Beef Cattle, Larry V. Cundiff, Keith E. Gregory, Robert M. Koch

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

Results from the first four cycles of the Germplasm Evaluation (GPE) Program at U.S. Meat Animal Research Center demonstrated that vast genetic variation exits among and within breeds for most bioeconomic traits in beef cattle. The range for differences between breeds was comparable in magnitude to the range in breeding value of individuals within breeds for most traits. Thus, significant genetic change can result from selection both between and within breeds. Breeds can be selected to optimize performance levels for important bioeconomic traits with a high level of precision much more quickly than intrapopulation selection.

No single breed or biological …

Effect Of Method Of Estrous Synchronization On Oocyte Quality And Follicular Insulin- Like Growth Factor (Igf-I), Thomas H. Wise, Ralph R. Murer

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

Of the two methodologies utilized in the beef industry to synchronize animals to estrus (prostaglandin regression of the corpus luteum or implanting/injecting progestin which results in estrus 48-60 hr after implant removal), conception and fertility are generally lower in progestin synchronization to estrus. Both technologies produce comparable results in relation to estrus and ovulation. Alterations in steroidal hormones of the follicle (progesterone/estradiol) are important in the maturation and quality of oocytes. Insulin-like growth factor (IGF-I) which can regulate follicular progesterone concentrations, may have a role in oocyte maturation and viability. Circulating progesterone concentrations alter luteinizing hormone (LH) pulse frequency and …

Contributions Of Ovum Cytoplasm And Uterine Environment And Postnatal Environment To Maternal Effects In Beef Cattle, Keith E. Gregory, Ralph R. Maurer

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

Any contribution or influence on offspring phenotype attributable to its dam, exceeding the inherited sample half of the dam's nuclear genes, is a maternal effect. Maternal effects can be classified into prenatal (e.g., cytoplasmic and uterine components) and postnatal [e.g., lactation, method of rearing (early weaning), plus other postnatal maternal components]. This experiment was designed with two objectives. The first objective was to determine the relative contributions of ovum cytoplasm and uterine influences on prenatal maternal effects by use of embryo transfer (ET). The second objective was to estimate breed differences in prenatal and postnatal maternal effects combined by evaluating …

Differences Among Parental Breeds In Germplasm Utilizationproject, Keith E. Gregory, Larry V. Cundiff, Robert M. Koch, Donald D. Lunstra

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

Large differences exist among breeds for most bioeconomic traits. These differences are the result of different selection goals in different breeds. Thus, over time, large genetic differences have accumulated among breeds. Results from the Germplasm Evaluation Program at the U.S. Meat Animal Research Center provide evidence that genetic variation between breeds is of similar magnitude to genetic variation within breeds for many bioeconomic traits. However, the heritability of breed differences approaches 100%, whereas, the heritability of differences within breeds for major bioeconomic traits varies from less than 10% to about 50% depending on the trait. Heritability of breed differences approaches …

Effects Of A Β-Agonist On Muscle Protein Degradation, Enzyme Activity, And Meat Tenderness In Steers, Tommy L. Wheeler, Mohammad Koohmaraie

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

It is generally accepted that muscle proteins are under continual degradation during normal growth. It has been estimated that 15 to 22% of the animal's total energy expenditure is for this muscle protein turnover. Regulation of the rate of muscle protein degradation could cause dramatic changes in rate and efficiency of muscle growth. Despite their importance in muscle growth, the mechanisms and control of skeletal muscle protein degradation are unknown. It has been hypothesized that several enzyme systems are involved at different stages of degradation, and that the calpain enzyme system (which occurs naturally in muscle) may initiate protein degradation …

Energy Expenditures Of Mature Cows During The Production Cycle, Calvin L. Ferrell, Tom G. Jenkins

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

The cow uses about 65% of the feed energy used in the production of beef cattle. Of that, about 74% is used for maintenance of the maternal body, 18% for lactation and 8% for pregnancy in the mature, producing beef cow. The growing- finishing animal uses about 35% of the total feed energy used for beef production. In the growing-finishing animal, maintenance costs may vary from 30 to 100% of the total feed energy consumed, with the lower proportion being at high intakes and rates of gain. Typically, in feedlot cattle this value ranges from 30 to 40%, whereas in …

Estimates Of Genetic And Phenotypic Parameters Of Pelvic Measures, Weight, Height, Calf Birth Weight, And Dystocia In Beef Cattle, Keith E. Gregory, Larry V. Cundiff, Robert M. Koch

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

Based on requirements for assistance at first parturition as two-year-olds, experimental results document the importance of dystocia in major breeds of Bos taurus cattle. In addition to the greater labor and managerial requirements associated with dystocia (calving difficulty), experimental results show that dystocia results in reduced perinatal calf survival and reduced conception rate in females in the subsequent breeding season when dystocia is experienced. There is not agreement on the value of pelvic measures as a predictor of dystocia at first parturition. Information is limited on the genetic relationship between pelvic measures and other factors that may be genetically associated …

Factors Influencing Fetal Growth And Birth Weight In Cattle, Calvin L. Ferrell

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

Fetal growth, as indicated by birth weight, has important influences on animal production. Birth weights lower than optimum are associated with reduced energy reserves, lowered thermoregulatory capability, and increased calf deaths at or near birth. In addition, low birth weights are related to low rates of growth after birth and decreased mature size. Conversely, birth weights greater than optimum are associated with greater calving difficulty. Primarily because of the increased calving difficulty, calf losses at birth and difficulties if rebreeding the cow are increased.

Fetal growth, hence birth weight, is influenced by numerous factors including number of fetuses, sex, parity …