Duration: 10/01/2009 to 09/30/2014

Administrative Advisor(s):

NIFA Reps:

Non-Technical Summary

Statement of Issues and Justification

Statement of Issues:

This proposal targets the national science roadmap for agriculture priority #7 to develop new and more competitive animal production practices and products. Beef cattle are important to most state's economies, and this project addresses several breeding and genetic aspects that are important to current and developing U.S. beef cattle production and management strategies, particularly in the southern region. Many traits such as health and hair coat characteristics have not been thoroughly quantified for degree of genetic influence or their impact on reproduction and growth.

Cattle diseases, such as Infectious Bovine Keratoconjunctivitis and Bovine Respiratory Disease Complex, and heavy infestations of specific external pests, such as ticks, have the potential to greatly reduce beef cattle productivity, especially in the Southern Region of the U.S. Producers not only experience reduced beef cattle performance but also have to bear the expense of treating cattle for these maladies, which combined can have a considerable negative impact on producer income.

Breed comparisons and even family comparisons are not static over time as these populations change due to selection strategies, and, conclusions from breed comparisons at a single point in time (i.e. 25 years ago) may not adequately explain current situations. Current performance assessments for breeds are needed to enhance producer breeding decisions for traits related to cow reproduction and calf survival in the Southern region of the United States. Additionally, there is limited research that characterizes the additive genetic control and prediction of breeding values for these important cow productivity traits, particularly in this region. Few research entities in the Southern region have enough cows and other resources to effectively conduct such research independently. A collaborative effort across locations in multiple states would be an appropriate way to address these issues. Historically, researchers in this area had long term (10 yr or more) projects that they published; today, funding organizations are unwilling to support such research. Current information using modern cattle is needed so that cow-calf producers in the Southern region can make informed breeding decisions to profitably produce cattle under their environmental challenges. Tropically-adapted breeds such as the Brahman (and to a lesser extent other adapted breeds such as those of Criollo or Sanga origin), are used widely in this region, however their offspring have a reputation for poor performance in stocker and feedlot operations on the Great Plains. As a result, many cow-calf producers in this region are attempting to use non-adapted cattle, such as British or other Bos taurus breeds.

As more emphasis is placed on genomics, many locations that have historically conducted cattle breeding research have reduced their populations and herd size. In the past ten years, new technologies have become available to identify individual genes throughout the bovine genome and independently assess their relationship to economically relevant traits (ERT) in the beef cattle industry. In order to locate these genes, DNA markers (also known as genetic markers) have been developed to aid in locating genes that can positively or negatively affect the phenotype of a specific trait. Finding genes with major effects is important in all traits especially those that are hard to measure and ones that are easily influenced by the environment, and incorporation of this information in selection schemes could enhance beef cattle improvement programs. However, large populations of cattle of known genetic background are needed to fully characterize new and emerging genetic markers.

In most areas of the world, cattle destined for slaughter are fattened on grass. In the southern U.S. this requires cattle that are well-adapted to the ambient conditions (high temperature and humidity) and it is usually expected that only Bos indicus or Bos indicus crosses can be sufficiently adapted to such conditions to grow rapidly and efficiently. Since both a light coat color and a short hair length contribute significantly to increased heat tolerance, it is possible that the combination of short hair and lighter coloration will result in an animal with high growth potential under grazing conditions in the southern U.S. without Bos indicus influence.

Justification:

It has been documented that beef cattle performance is impacted by diseases, such as Infectious Bovine Keratoconjunctivitis and Bovine Respiratory Disease Complex, and specific external parasites, such as ticks. However, it is less well documented as to what extent resistance to these maladies is influenced by beef cattle genetics. Because external parasites tend to develop resistance to pharmaceuticals used for their control, any genetic means of reducing the susceptibility of cattle to infestation would be of value to the cattle industry in tropical and sub-tropical areas. If genetic variation for resistance to these maladies exists, this information could be utilized by producers to identify genetic types that express resistance to these maladies with a subsequent increase in herd productivity being achieved at a lower cost.

The 13 states in the Southern region (AL, AR, FL, GA, KY, LA, MS, OK, NC, SC, TN, TX, VA) account for 14 million beef cows (42.3% of the nation's beef cow inventory) and 406,200 producers (48.9% of the nation's cow-calf producers) (USDA, 2002). A variety of breeds and crosses are utilized in this region. It is important to provide current characterization of breeds that have potential to improve productivity in regions that have substantial environmental challenges. Direct selection using estimated or predicted breeding values may represent another strategy for improvement of traits related to cow reproductive success and for calf survival. Most research facilities do not have enough cows to adequately evaluate their own results from analyses of traits related to cow reproduction and calf survival. Combining data from multiple locations will provide adequate numbers of records for analyses of such traits. Although the Southern United States has abundant quantity of forage for much of each year, the region can be considered stressful to cattle for many reasons, especially high heat conditions. The predominant forages range from low quality bahiagrass along the Gulf Coast to fescue in the upper South. Summer conditions are often similarly stressful throughout the South, as the toxic endophyte present in fescue amplifies heat stress conditions. Analyses of traits using data from across this stressful region would permit accumulation of substantial numbers necessary for appropriate assessment and would expand application of results throughout this critical production area.

Improving beef cattle performance through genetic selection traditionally involved observing physical characteristics of an animal, choosing the best individual, and using them as parents to produce the next generation. Progress with this type of selection was generally slow because the true genetic value was unclear until performance of the individuals progeny could be measured. This progeny performance information, along with performance of the individual and its relatives, were combined using advanced statistical analysis to produce what is known today as an expected progeny difference (EPD), a measure of an individuals genetic worth. For a variety of traits within a specific breed of cattle, EPD evaluate traits from a collective standpoint where all gene effects that control expression of a phenotype are added together to create a genetic value for each individual. Development of DNA marker and SNP (single nucleotide polymorphisms) technologies has allowed for the addition of a new selection tool, which creates the opportunity to evaluate individuals based on their genotypes from a DNA sample. This information gives producers the ability to make selection decisions much earlier in the growth and development period to identify economically efficient animals. Numerous cattle populations of known genetic background need to be evaluated for genetic markers to understand their utility across the entire industry.

Genetic tests for DNA markers that are associated with simply inherited traits such as coat color, polled condition, several genetic defects, and complex traits like marbling, tenderness, and other carcass traits are being marketed commercially by several U.S. companies. These companies market their tests by claiming a relationship of certain markers to particular traits and the amount of phenotypic variation observed when the marker is present or not. Validation of current markers as well as the effects of newly discovered genes on phenotypic traits will continually need to be investigated. The question for each newly discovered gene is: Does it have an association to one or many traits and, if so, to what degree? These markers also allow for the evaluation of traits that are hard to measure on live animals. For example, tenderness is a very important attribute influencing consumer satisfaction, but it is difficult to measure in that animals must be harvested for an accurate assessment. Similarly, reproductive efficiency and longevity greatly impact productivity. These traits are usually difficult to measure because of the many environmental factors that can mask the underlying genetic variation. Once major genes are identified, independent populations of animals with suitable phenotypes and pedigree information are needed for genetic characterization of these markers to determine how best to apply this new information.

Over the past two decades black has become the preferred color of feedlot and slaughter cattle in the USA, including the Southern Region. As a result, not only has the influence of Angus cattle increased, but the black gene has been incorporated, through upgrading and selection, into a number of previously red breeds such as the Simmental, Limousin, Gelbvieh, etc. This is in spite of the fact that black colored cattle will absorb more solar radiation than red or other lighter-colored cattle. Studies by Mader et al. (2002) and Davis et al. (2003) both showed rather dramatic (up to 0.5º) lower body temperatures while under heat stress for white (dilute-colored Charolais crossbred) as compared to black feedlot steers. This advantage is comparable to the effect of the Slick hair gene for heat tolerance reported by Olson et al. (2003). The combined effects on heat tolerance of cattle that are both light colored and slick-haired have never been evaluated.

While there are limited data from feedlot studies showing that steers with white hair are more heat tolerant than those with dark red or black hair, there is no information available on the pasture growth of cattle varying in coloration and hair coat length. Also, if a specific coloration, hair length, or coloration-hair length combination results in increased tick or fly resistance, it could have a major impact on the genetic types utilized in crossbreeding programs for the Southern region and throughout the tropical and sub-tropical areas of the world utilized for cattle production.

The goal of this project is to address component traits with known genetic influence that impact productivity in cow-calf operations in the Southern Region. Several traits related to health and hair coat have not been well characterized for family differences and may be quite important for adaptation, and therefore could influence reproduction and growth. More thorough genetic evaluation of these adaptation-type traits may allow for previously unrecognized variation in beef cattle production systems to be identified. Many of the traits of interest are categorical in nature, and genetic evaluation of these types is complicated, but needs further study. If this project is not conducted, many questions about these traits and their potential contribution to production system variation will remain, which would likely result in reduced production efficiency in the U.S. beef cattle industry.

Related, Current and Previous Work

- Review of accomplishments from the previous project (S-1013):

Objective 1: Determine heterosis effects in crosses representing two or more diverse, tropically adapted beef breeds.

Accomplishments: Use of the Criollo breed Romosinuano may permit cow-calf producers to take advantage of tropical adaptation and heterosis for a variety of production traits while possibly avoiding less desirable performance of some traits of tropically adapted cattle, such as poor animal temperament, poor marbling score, and late sexual maturity in females.

Objective 2: Characterize diverse, tropically adapted beef breeds in subtropical and temperate areas of the United States.

Accomplishments: Results clearly demonstrate the superior environment in Nebraska for cow-calf production compared to that in Louisiana. Cow breed types ranked the same in both environments. Romosinuano-sired cows appear slightly superior to other sire breed types for reproductive traits. This area of research has been identified as needing further investigation as noted below.


Objective 3: Determine genetic variation in disposition and parasite resistance in beef cattle and their association with economically important traits.

Accomplishments: Phenotypic correlations among chute score and exit velocity with postweaning gain for replacement heifers were, in general, negative and significant. Phenotypic correlations among weaning exit velocity and summer exit velocity with pregnancy rate were negative and important for replacement heifers. Sire effect was highly significant for all temperament measurements indicating significant genetic variation exists for temperament traits and fecal eggs per gram. Calf temperament scores from pre-weaning through 56 days postweaning are very repeatable measurements. Thus these measurements can be done at weaning and provide an accurate indication of the lifetime temperament of that animal. In addition, animals that are routinely worked through a cattle facility will become accustomed to human interaction and their overall temperament scores will continue to improve from weaning through yearling.


Objective 4: Establish a DNA bank to utilize molecular markers to validate traits of economic importance.

Accomplishments: All participating locations have stored DNA, tissue, or white blood cells on calves at birth or shortly before weaning. The DNA samples collected will be available for future discovery and utilization of molecular markers to validate traits of economic importance. This area of research has been identified as needing further investigation as noted below.
As this proposed project complements and builds upon the previous (S-1013) project, background on individual proposed objectives are discussed below. Objectives 1, 2 and 4 pertain to production issues known to have genetic influences but need to be better quantified and lend themselves to study in multistate partnerships.

- Literature review for current proposal

Objective 1a. Infectious Bovine Keratoconjunctivitis

Infectious Bovine Keratoconjunctivitis (IBK) is a serious eye disease [evidenced by fact that four major reviews (Wilcox, 1968; Baptista, 1979; Punch and Slatter, 1984; Brown et al., 1998) have been directed towards various aspects of this disease] that impacts cattle of all ages; however, its greatest impact appears to be on reduced performance of calves during the preweaning period (Thrift and Overfield, 1974; Frisch, 1975; Cobb et al., 1976; Killinger et al., 1977; Ward and Nielson, 1979; Snowder et al., 2005) as well as lower prices received for calves and feeder cattle (Killinger et al., 1977; Schroeder et al., 1988; Sartwelle et al., 1996a,b; Smith et al., 1999; Troxel et al., 2002; Barham and Troxel et al., 2007). Similarly, IBK impacts marketability of breeding cattle, especially bulls, since they utilize their sense of vision (Blockey, 1978; Geary and Reeves, 1992; Thrift and Overfield, 1974) to detect females in estrus.

It has been estimated that IBK is observed in almost half of U.S. beef cattle herds, with 3% of all beef cattle affected annually (Cobb et al., 1976). A Missouri study (Webber and Selby, 1981) indicated that 45.4% of herds were affected by IBK, and the infection rate was estimated to be 8.75/100 cattle, and as many as 20% of afflicted cattle lose their sight at least temporarily (Spradbrow, 1967). USDA estimated that IBK costs the U.S. cattle industry at least $150 million annually (Richey, 2003).

Incidence of IBK has been observed to be greater for bull calves (Thrift and Overfield, 1974; Cobb et al., 1976; Ward and Neilson, 1979) and for most Bos taurus genetic types (Frisch, 1975; Cobb et al., 1976; Webber and Selby, 1981), relative to Bos indicus genetic types (Jackson, 1953; Ward and Neilson, 1979; Webber and Selby, 1981; Thrift and Thrift, 2003; Snowder et al., 2005). Further, increased IBK incidence has been associated with reduced eyelid pigmentation (Frisch, 1975; Caspari et al., 1980; Pugh et al., 1986), especially in Hereford cattle. Published estimates of genetic parameters involving incidence of IBK are limited. Snowder et al. (2005) reported an overall direct heritability of 0.22 ± 0.02 (estimates varied from zero to .28 for the various genetic types) for IBK incidence; direct heritability was 0.25 ± 0.04 for Angus.


Objective 1b. Bovine Respiratory Disease Complex

Bovine respiratory disease (BRD) complex is a continual health problem in U.S. feedlot cattle, despite improved vaccines and beef quality assurance programs. In the 1980s, UDSA-ARS identified BRD as a primary problem for the beef industry and developed a national BRD research project (Hutcheson et al., 1984; Hutcheson and Cole, 1986). Since that time, in spite of many new respiratory disease pharmaceuticals, feedlot morbidity and mortality have continued to increase. Lonegran (2004) analyzed the USDA NAHMS Sentinal program and Benchmark Performance program databases and concluded that from 1994 to 2003, death loss and death due to BRD, respectively, increased by 6% and 9% per year. Hutcheson (2008) estimated that the present industry BRD mortality and morbidity rates were 10% and 30%, respectively. It is not known what portion of this industry trend in BRD is due to genetics.

Genetic variation for BRD has not been widely studied, but appears to be substantial. Heritability of BRD incidence in calves preweaning was reported to be .10 to .20 by Muggli-Cockett et al. (1992). Snowder et al. (2006) reevaluated these data and estimated heritability to be .08 in the same data, but stated that characterization of accurate phenotypes is very important in regard to study of animal health. Inaccurate classification of phenotypes can contribute to biased and reduced heritability estimates even when substantial genetic variation exists. Many components of animal immune function have been reported to have significant genetic influence. Antibody response in pigs has been shown to have heritability of .16 to .27 (Wilkie and Mallard, 1999). Neutrophil function heritability in dairy cows has shown wide estimates of 0 to .88 (Detilleux et al., 1994). Heritability of antibody response following vaccination in dairy cows has also been reported to be moderate to high (Wagter et al., 2000). Knap and Bishop (2000) stated that animal production has relied mainly on medication, vaccination and management techniques for the control of animal health, and as a consequence, health-related traits have played a minor role in livestock breeding.

Objective 1c. Specific External Parasites

Prayaga (2003) estimated tick counts on 31 different genetic types including tropically adapted British (Belmont Adaptaur), Sanga-derived, Zebu cross, Zebu, and Continental breeds in Queensland Australia and observed Belmont Adaptaur, Sanga-derived breeds, and crossbred populations with greater quantities of Continental, Sanga, and Britsh breeding expressed higher tick counts. Cardoso et al. (2006) reported a heritability of .20 for tick counts in Braford cattle, but the heritability increased to 0.25 when cattle with very few ticks (low tick load) were eliminated.

While Prayaga and Henshall (2005) failed to observe a relationship between tick count and hair score in a population of largely short-haired crossbred cattle, it is widely believed among cattle producers in tick endemic regions that cattle with shorter hair are more resistant to tick infestations. There seems, however, to be little research evidence to support this view. Turner (unpublished observations included in Turner and Schleger, 1960) stated that short hair would facilitate removal of ticks by licking, which has been shown to affect tick infestations and some limited evidence has been found that the degree of infestation in the field is related to hair length. Verissimo et al. (2002) found a highly significant correlation between hair length and tick count in cattle of varying percentages of Holstein and Gyr, but the effect of long hair was confounded with Bos taurus composition. Brown et al. (1992) reported a high heritability value for horn fly count on cows of various breeds (0.59 and higher depending on method of calculation) indicating that genetic type differences exist for horn fly count.

Upon review of multistate regional projects there does not appear to be any duplication of projects which relate to objective 1. No projects are evaluating Infectious Bovine Keratoconjunctivitis. One project NC1027: An integrated approach to control of bovine respiratory disease is focusing more on development of new vaccines whereas this project is focused on utilizing established vaccines and the best times of vaccination, type of vaccine used (killed versus modified live) and genetic and phenotypic interactions of cattle primarily located in the Southern region of the U.S., and is not evaluating genetic aspects of vaccination response. In addition, no multistate research projects are studying external parasites primarily ticks. One multistate project S1030: Flies Impacting Livestock, Poultry and Food Safety, however, only focuses on muscoid flies and house flies and deals with no other external parasites.

Objective 2. Cow reproductive and maternal traits are especially important for cow-calf producers, including calving and weaning rate as a percentage of cows exposed to bulls in the previous breeding season (sometimes called calf crop born and calf crop weaned). Heterosis is influential on these traits (Cartwright et al., 1964; Peacock and Koger, 1980; Olson et al., 1990; 1993). Breed comparisons for these types of traits in crossbred and purebred beef cattle have been limited (e.g., Riley et al., 2001a-b, Chase et al., 2004; Cundiff, 2005, USMARC, 1974-2006) because of the necessary long duration of such projects, the long gestation length of cows, and the current lactation management used by cow-calf producers (i.e., wean calves at approximately 7 mo of age). Large numbers of records and animals are required, and the binomial distribution of these traits complicates statistical analyses.

Unlike the dairy industry, which has a favorable industry structure and characteristics for investigation of the improvement of fertility traits in cattle (Weigel, 2006), the U.S. beef industry faces more difficulties in research involving the estimation of genetic parameters or the assessment of breed differences. Perhaps only a handful of research entities are capable of addressing such questions by themselves. Nonetheless there have been valuable results reported for unique regions of North America (e.g., Bailey, 1991; Arthur et al., 1993; Brown et al., 1997), and particularly for the Great Plains (Cundiff, 2005; USMARC, 1974-2006). An equivalent assessment of breeds across the Southern United States has not yet been accomplished.

Upon review of multistate regional projects there does not appear to be any duplication of projects which relate to this objective. One multistate project NC1038: Methods to increase reproductive efficiency in cattle focuses primarily on dairy cattle and also does not focus on cows in the Southern region. The objective of this project is unique because it focuses cattle in the Southern region as well as tropically adapted breeds of cattle which are not included in any other multistate project.


Objective 3. Mapping of the bovine genome has resulted in detection of many quantitative trait loci (QTL) for various beef cattle production traits. This information has been used by several companies to develop and market genetic marker tests for genetic improvement. Markers can be used to enhance within-breed selection or, by selection within a cross, to capitalize on between-breed variation (Dekkers, 2004). Using the results of DNA-marker tests to assist in selection of parents is called Marker-Assisted Selection (MAS). In some cases, genetic marker tests may be commercialized before collection of valuable field data (Van Eenennaam et al., 2007). For producers to feel confident with the use of these markers, independent validation studies must be conducted to produce unbiased information. Problems with validation projects include the high costs of genotyping animals and having large and diverse populations of animals with adequate phenotypic data.

Much of the initial validation work has been done in two areas of beef quality, marbling (Barendse et al., 2004; Casas et al., 2005; Moore et al., 2003; Rincker et al., 2006; Thaller et al., 2003) and tenderness (Casas et al., 2006; Page et al., 2002, 2004; White et al., 2005). Other studies have evaluated both types of beef quality markers with multiple breed and breed types (Van Eenennaam et al., 2007). Findings varied from association to non-association of markers to phenotypic measures citing different reasons for these variable results. Other reports have addressed the relationship between EPDs and markers for a particular trait. Barendse et al. (2005) reported proven sires with desirable EPDs for a particular trait having undesirable genotypes or no markers for that trait. This information creates producer uncertainty when deciding whether to implement this technology in selection processes. Another marker that has generated some interest in meat quality traits involves the leptin gene (Schenkel et al., 2005), also shown to have influence on reproduction (Almeida et al., 2003). Some recent reports have focused on the relationship of QTL with growth rate and feed efficiency (Nkrumah et al., 2007; Barendse et al., (2007).

With the advancement of single nucleotide polymorphism (SNP) technology, it is now possible to explore the entire genome. Success of commercial marker-assisted selection is unclear and undocumented and will depend on the ability to integrate marker information into selection and breeding programs (Dekkers, 2004). As QTLs are identified and new markers developed, more and more validation trials will be needed to further investigate existing and new markers. The focus of this objective is to create a gene bank that can be used to provide information on genetic markers as well as identifying potential new genes in the future with significant effects on production traits in beef cattle located in the Southern region of the United States.

Upon review of multistate projects there were three projects that relate to genomic data; NCERA199: Implementation and strategies for National Beef Cattle Gene Evaluation; NCDC213: Interpreting cattle genomic data: Biology, Applications and Outreach and WERA001: Beef Cattle Breeding in the Western Region. However, this project is unique in our objective as it samples a population of beef cattle and an environment that is not found in these other projects. Therefore due to the unique environment and population of cattle involved in this multistate research project, we do not feel that there is duplication of this objective with any other multistate research project.

Objective 4. Bonsma (1949) discussed the appropriate coloration of cattle to be resistant to high temperatures and high solar radiation as having a white, yellow or reddish brown hair coat with yellow, reddish brown or black skin. Finch et al. (1984) reported that dark red and red Brahman and Shorthorn steers had a higher absorption of solar radiation than white steers. Mader et al. (2002) examined the effect of hair color in feedlot steers during Nebraska summer months and found that tympanic temperatures of dark steers (including pre-dominantly black but some red) were 0.5º C higher during the afternoon and early evening than those of white (presumably Charolais crossbred) steers. The dark steers also panted more and tended to bunch more than white steers under warm conditions. In a subsequent study, Davis et al. (2003) compared the tympanic temperatures of black vs. white Charolais ´ Angus crossbred steers while under severe heat stress and being full-fed. The temperatures of black steers were higher throughout the day than those of white steers and averaged 0.5º C higher at 1900. Hutchinson and Brown (1969) reported that black hair coats absorb more solar radiation than white hair coats but that the radiation penetrated further into white than black hair coats. da Silva et al. (2003) examined the reflectance, transmittance, and absorptance of haircoat and skin of black, red, white, and gray hide samples from Bos taurus and Bos indicus cattle. Red coats reflected more of the solar radiation than black, and white and gray coats tended to reflect even more.

Study of the Slick hair gene began with determination that Senepol cattle were more heat tolerant than Angus and Hereford cattle at the Subtropical Agricultural Research Station near Brooksville, FL. Senepol is a Bos taurus composite breed developed on St. Croix, U.S. Virgin Islands and is noted for being very short-haired. Rectal temperatures of Senepol cattle under heat stress were often 0.5º C lower than Angus and Hereford cattle (Hammond et al., 1996). Crosses of Senepol with Angus and Hereford were subsequently found to be similar in heat tolerance to Senepol (Hammond et al., 1996). Observation that calves of Senepol ´ Angus cows generally possessed either the short, sleek hair of the Senepol or normal, longer hair, along with other evidence led to the conclusion that a major gene for hair type was dominant in mode of inheritance (Olson et al., 2003). The hair weights of calves with slick hair (0.74 g) were much less than those of calves scored as normal-haired (2.41 g). Comparisons of the heat tolerance of Charolais-sired, slick- and normal-haired 25% Senepol cattle of the same breed composition showed that slick-haired animals were able to maintain rectal temperatures approximately 0.5º C lower and had reduced respiration rates under heat stress.

Hammond and Olson (1994) have previously shown that Senepol cows grazed more during the daylight hours than Hereford cows. Olson et al. (2006) found Holstein bulls identified as possessing the slick phenotype (0.026 g) had less hair than their normal-haired half-brothers (0.210 g), had fewer breaths per minute, and maintained slightly lower rectal temperatures even though they were breathing much more slowly.

Olson et al. (2006) also showed that a higher percentage of the slick-haired, upgraded bulls continued to graze later in the morning and returned to grazing earlier in the afternoon and gained significantly more weight than their normal-haired siblings (40.1 vs. 35.5 kg) in spite of having heavier initial weights. Turner and Schleger (1960) mentioned that coat score at weaning was weakly correlated with preweaning gain but well correlated with postweaning gain. In Florida, Olson et al. (2003) found that there was no growth advantage for slick-haired Charolais-sired calves up to weaning but such calves did gain faster than their normal-haired contemporaries postweaning as long as high temperatures persisted.

Upon review of multistate projects there does not appear to be any duplication of projects which relate to objective 4.

A CRIS search was performed on July 13, 2009 with the key words of beef cattle and breeding or genetics. There were 27 projects identified, but none of those projects presented redundant ideas or procedures to those in this proposal. How the proposed new project relates to the previous (S-1013) project is discussed below:

- Linkage of proposal (SDC334) objectives with previous research project (S-1013):

Objective 1: Estimation of genetic variation associated with susceptibility / resistance to specific measures of diseases in our proposal is a new concept and does not directly relate to any of the objectives and accomplishments from the previous project.

Objective 2: Characterization of diverse, tropically adapted breeds for reproductive and maternal performance is related to work conducted in the previous project (objective 2). Collaborative efforts across Southern locations evaluating current genetics in cow herds will further quantify the above mentioned accomplishments from the previous project and will specially focus on female reproductive and maternal performances which are the most economically important traits for cow-calf production.

Objective 3: Establishment of a DNA bank for future discovery and characterization of molecular markers is basically a continuation to an objective in the previous project (objective 4) in which DNA samples will continue to be collected and archived from pedigreed beef cattle populations.

Objective 4: Evaluation of relationships between hair coat/hair luster and production traits was not collaboratively addressed in the previous project. However, there were some contributors that incorporated evaluation of hair coat/luster/shedding in the previous project and determined that this area needs further investigation for advancing improvement of sub-tropical adaptation in our southern environments.

Objectives

1. Estimation of genetic variation associated with susceptibility/resistance to specific measures of disease stress in cattle managed on forage.
   
2. Characterize diverse, tropically adapted beef breeds in subtropical and temperate areas of the United States with emphasis on cow fertility and productivity in comparison to Bos indicus influenced breeds and types.
   
3. Establish a DNA bank for characterization of molecular markers, genetic parameter estimation and future discovery of genes that influence economically important traits in pedigreed beef cattle populations.
   
4. Evaluation of relationships between hair coat and production traits in beef cattle breed types.
   

Methods

Objective 1a. Calves will be evaluated for evidence of Infectious Bovine Keratoconjunctivitis during the preweaning period at 10 locations (Kentucky, Arkansas, Texas (McGregor, Uvalde), Louisiana (Baton Rouge, Homer, Iberia), Florida (USDA-ARS, STARS, Brooksville) and Mississippi (State College, Brown Loam Experiment Station) using a subjective scoring system where 0 = no evidence of IBK in either eye and 1 = evidence of IBK in one or both eyes. Angus will be the predominant genetic type evaluated at most of the locations; however, some locations contributing to other aspects of this multi-state research effort will evaluate similar crossbred genetic types produced at the different locations. Variance components (direct, permanent environmental and maternal effects) for resistance to Infectious Bovine Keratoconjunctivitis will be estimated using a derivative-free REML algorithm (Graser et al., 1987) facilitated by the computer programs of Boldman et al. (1995). From these variance components, genetic parameters for direct and maternal effects associated with Infectious Bovine Keratoconjunctivis will be calculated. F.A. Thrift (Kentucky) will be responsible for data assimilation from the various locations, statistical analysis of the combined data set and publication of results for the Infectious Bovine Kertaconjunctivitis component of this objective. Objective 1b. This objective is to establish a resource of defined health phenotypes and biological samples in conjunction with growth in cattle of known genetic and management backgrounds in response to BRD viral vaccines. Participating locations of this objective include Louisiana (Hill Farm and Iberia), Mississippi (Brown Loam), Arkansas (Hope, Little Rock and Monticello), and Texas (McGregor and Uvalde). Although the populations of cattle in this objective were not specifically designed for gene discovery, they will be useful for genetic characterization studies Cattle will be vaccinated for bovine respiratory disease (BRD) at various locations at the ages according to their standard operating procedures. Participants may use killed or modified live (MLV) vaccines at their respective locations, but the same killed and MLV vaccines from a single manufacturer will be utilized across locations. All calves will have known sires. Weight, rectal temperature and blood serum will be collected on calves at the time the booster vaccination of a killed vaccine is administered or the time a single MLV is administered (Day 0). Weight, rectal temperature and blood serum will also be collected 28 days later. Sera will be frozen and banked for later assays as funding allows. Genomic DNA will also be collected and stored for future use as genetic markers for immune function and health become available. Cattle will be observed daily for visual signs of illness and scored on a 1 to 5 scale for fill (1 = normal, 5 = extremely gaunt), attitude (1 = normal, 2 = slight lethargy, 3 = moderate lethargy, 4 = severe lethargy, 5 = nonambulatory), ocular discharge (1 = none, 5 = extreme), and nasal discharge (1 = none, 5 = extreme). Animals suspected of having BRD will have rectal temperature and these measures recorded and all treatments recorded. Funding opportunities will be pursued so that serum neutralizing IgG titers for IBR and BVD Type 1 and Type 2 can be investigated. An existing panel of genetic markers spanning the bovine major histocompatabilty complex (MHC) genomic region will also be investigated if funding can be acquired. Cattle at cooperating stations that are evaluated for vaccine response and that are subsequently fed and have carcass data collected will have detailed treatment records and may have lungs evaluated for lesions at harvest by trained personnel. J.W. Holloway and A.D. Herring (Texas) will be responsible for assimilation of data for this BRD component of Objective 1. Statistical analyses will investigate sire effects for rectal temperature, antibody titers and clinical evaluations of health. Vaccination response of the same products evaluated across different location/age of administration will also be evaluated. Objective 1c. Tick counts will be obtained from bull and heifer calves at weaning and at yearling age at participating locations (Virgin Islands, Mississippi-Brown Loam). Heifers will also be evaluated at first breeding. Cattle will be evaluated prior to any treatment (dip or spray) to remove external parasites. Tick counts will be conducted using the methods of Lima et al. (2002) and Castro et al. (2005). Cattle will be restrained in a chute and photographs of lateral, dorsal and ventral body surfaces of each animal will be recorded using a hand held digital camera. Special care will be taken to photograph the area from just under the tail down to between the rear legs as this is the area where most of the ticks are commonly found on the cattle. Images will be reviewed on a monitor and total tick counts will be determined for each animal. Genetic types evaluated will vary across locations and will consist of purebred and crossbred Bos taurus and Bos indicus cattle. Data will be analyzed using genetic type, sex, time of year and location in the model to evaluate differences in tick counts. The use of any tick control methods will also be incorporated into the analysis. R.W. Godfrey (Virgin Islands) will be responsible for data assimilation from the various locations, statistical analysis of the combined data set and publication of results for the external parasite component of this objective. The proposed IBK research effort is designed to classify cattle according to presence or absence of IBK and is not oriented towards finding a treatment cure for IBK. Animals involved with the response to BRD vaccine effort will be evaluated for rectal temperature and presence of non-typical symptoms that are observed in healthy animals. Animals involved in tick presence effort will have tick count quantified. Management of all animals in Objective 1 is of typical industry practices. Evaluation of these animal, health-related traits by animal scientists is accepted by referred journals, and therefore, veterinary expertise is not a requirement to fulfill this project objective. In situations where illness is determined severe, consultation from a veterinarian will be sought, which is typical industry practice. Objective 2. Participating locations will include Arkansas (Fayetteville and Booneville), Florida (Brooksville and Gainesville), Louisiana (Hill Farm and Iberia), Mississippi (Brown Loam and Starkville), North Carolina (Tidewater, Reidville, Goldsboro, and Butner), Oklahoma (El Reno), South Carolina, and Virgin Islands. At a minimum, the following data for heifers and cows will be collected at respective locations: (1) Breed of cow, (2) Sire/sire breed and dam/ dam breed of cow, (3) cow birth date, (4) Mating information (natural or artificial insemination; single or multiple sires; number of cows per bull; season or insemination dates), (5) Predominant forage in pastures, (6) Sire/sire breed of calf, (7) Calving date, (8) Calving difficulty (1 = normal; 2 = easy pull; 3 = hard pull; 4 = caesarian section; note the abnormal presentation of calf), (9) Calf vigor issues (1 = normal; 2 = weak but nursed without assistance; 3 = weak and assisted to nurse; add any notes), (10) Birth weight, (11) Weaning date, (12) Weaning weight, (13) Date of death and reason/notes for cow or her calf, (14) Date of culling and reason/notes for cow or her calf, and (15) Date of occurrence and notes related to any health issue. These data will be used to construct reproductive traits and calf survival (to various ages), calf crop born and calf crop weaned (both as 0-1 traits where 1 indicates success and 0 indicates failure); occurrence of calving difficulty or inadequate newborn vigor (again both as 0-1 traits, where 1 indicates occurrence); calving interval; and weaning weight per cow exposed. Detailed notes may also permit analyses of other critical traits, e.g., those related to animal health issues and culling. Linkage among herds will be accomplished where possible by use of AI (in particular, Angus or Charolais) sires and tropically-adapted sires from the Germplasm Evaluation project at USMARC. Where possible, exchange of bulls will be used to enhance linkage of herds that are not mating cows using AI. Participating locations will submit all of the above in November of each project year to Gary Hansen, North Carolina State University and Wayne Wyatt, LSU AgCenter. Statistical analyses will be conducted by Mauricio Elzo, University of Florida. Although the primary emphasis will be to estimate breed effects (and their interaction with other key effects, e.g., state, for cow reproduction and maternal traits, every effort will be made to maximize the number of traits evaluated from the data collected, and where possible to estimate genetic parameters and thereby breeding values within/across breeds for select traits. Objective 3. Participants of this objective include Arkansas (Fayetteville, Hope, Little Rock, and Monticello), Kentucky, Louisiana (Hill Farm and Iberia), Mississippi (Brown Loam and Starkville), Oklahoma (USDA-ARS El Reno), North Carolina (Tidewater, Goldsboro, Butner, Reidsville), Texas (McGregor and Uvalde), and Virgin Islands. DNA samples will be collected from pedigreed populations of cattle (purebred and crossbred) from various units throughout the Southeastern United States in conjunction with all objectives. Whole blood will be harvested in purple top tubes, transferred to two 2 ml cryotubes and stored in a -80°C freezer at each location until testing is determined. Whole blood or tissue samples will be taken from each animal including calves dead at birth. Data on each animal will include individual, sire, and dam identification, breed or breed type, and location. Phenotypic information will be collected on each animal based upon the type of performance data required for objectives 1, 2, and 4. Coordinators for this objective will be Gary Hansen (North Carolina) and Trent Smith (Mississippi). A catalogue of information including phenotypic data and DNA samples from the different locations will be assembled and updated annually. Objective 4. Cattle will be evaluated at key points during the production cycle in Virgin Islands, Texas (McGregor and Uvalde), Louisiana (Hill Farm and Iberia) and Mississippi (Brown Loam and Starkville). Bull and heifer calves will be evaluated at weaning and up to a year of age. Heifers will be evaluated at first breeding and cows will be evaluated at the start of the breeding season each year. At each time point rectal temperature, and surface temperature if possible, will be measured for each animal using a rectal thermometer and a hand held infrared thermometer, respectively. Surface temperature will be measured at three locations on the animal, the rump, over the ribs and the shoulder. Respiration rate will be determined by visual observation and counting of breaths taken and adjusted to breaths/minute. All temperatures and respiration measures will be done with the animal in the chute, but not squeezed, and in the shade. At each evaluation animals will also be scored for hair coat type and color. Hair coat luster and length will be evaluated using a numerical scoring system. Hair coat luster will be evaluated using the following 5-point scale: 1 = glossy, healthy appearance; 2 = slightly glossy with patches of dull; 3 = intermediate between glossy and dull; 4 = mostly dull, some indication of unthriftiness; and 5 = dull and unthrifty. Hair length score will be evaluated using the following 5-point scale: 1 = short; 2 = shows some winter growth; 3 = intermediate in length; 4 = long in places, but intermediate in others; and 5 = long. Hair samples will be clipped from an area 2 in x 4 in over the rump, the ribs and the shoulder and analyzed for total dry weight, number and length of hairs. Pedigree information, single generation, will be collected for each animal. Genetic types evaluated will vary across locations and will consist of purebred and crossbred Bos taurus and Bos indicus cattle. Data will be analyzed using genetic type, sex, time of year and location in the model to evaluate differences in temperatures, respiration rates, hair coat scores. R.W. Godfrey (Virgin Islands) will be responsible for data assimilation from the various locations, statistical analysis of the combined data set and publication of results for the external parasite component of this objective.

Measurement of Progress and Results

Outputs

• scientific abstracts and presentations
• journal articles
• web-based extension publications
• DNA bank with and pedigree and associated phenotypes

Outcomes or Projected Impacts

• If genetic variation for Infectious Bovine Keratoconjunctivitis, Bovine Respiratory Disease Complex and cattle ticks can be better quantified from Objective 1, this information could be utilized by beef producers to identify cattle genetic types that express resistance to these maladies with a subsequent increase in herd productivity being achieved at a lower cost.
• Participation by multiple states in Objective 2 will provide the large number of records needed to appropriately analyze reproductive data and calf survival and allow for better breeding recommendations to producers.
• Data and DNA collected in Objective 3 will allow for characterization of new genetic markers as well as provide phenotypic data for potential discovery of new genes of interest that influence beef production.
• If genetic variation of hair coat type (length and color intensity) and its influence on production traits can be quantified in objective 4, cattle producers in the Southern region, as well as other tropical and sub-tropical regions, can utilize this information in breeding programs.

Milestones

(0):s project is designed so that no time-linked accomplishments must be completed before subsequent activities begin. However, analyses will be accomplished by individual participants annually, with results shared at an annual meeting. Progress and status of the project will be assessed by the participants in consultation with the administrative advisor annually.

Projected Participation

View Appendix E: Participation

Outreach Plan

Multiple avenues will be used to disseminate research results to animal scientists and beef cattle producers. Information will be made available to animal scientists through refereed and non-refereed articles, technical publications, as well as through organized symposia and selected papers at professional meetings, and books. Information will be disseminated to the states' beef associations such as the Cattlemen's Association, to beef cattle trade publications such as "Beef," and to farm publications and trade journals in the various states. The information will also be provided to livestock extension educators in the various states to be used in continuing education programs. Additionally, a number of the project participants have cooperative extension assignments and will include project findings in newsletters and fact sheets aimed directly at beef cattle producers.

Organization/Governance

A technical committee will be organized upon project approval. Operational procedures to be followed will be according to those described in the Guidelines for Multistate Research Activities. The voting members of the regional technical committee will include one representative from each cooperating agricultural experiment station or institution appointed by the director and a representative of each cooperating USDA-ARS or other government unit. The administrative advisor and the CSREES representative will be considered nonvoting members. All project participants, whether voting or non-voting, will be eligible for office. The offices of the regional technical committee will be the chair, vice-chair and secretary and will serve as the executive committee. These officers for the first year will be elected at the organizational meeting for the technical committee. In subsequent years the officers will be elected annually and may succeed themselves. The chair, in consultation with the executive committee, will appoint subcommittees to facilitate the accomplishment of the various research and administrative tasks involving the cooperating institutional representatives. Such tasks may include, but are not limited to, research planning and coordination, development of specific cooperative research procedures, assimilation and analysis of data from contributing scientists, and publication of regional bulletins. The duties of the technical committee will be to coordinate work activities related to the project. The chair, in accord with the administrative advisor, will notify the technical committee of the time and place of meetings, prepare meeting agendas and preside at meetings of the technical committee and the executive committee. The chair is responsible for preparing the annual progress report and coordinating the preparation of regional reports. The vice-chair assists the chair in all functions. The secretary records the minutes and performs other duties assigned by the technical committee or the administrative advisor. Annual meetings will be held by the technical committee for the purpose of conducting business related to the project. During each annual technical committee meeting, the subcommittees will report on their progress and identified needs to the entire committee. Considerable time will be devoted to the discussion of these reports.

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