CROSSBREEDING STRATEGIES: INCLUDING TERMINAL VS. MATERNAL CROSSES

The dramatic changes and volatility cow-calf production system input costs and calf values have many producers wondering about the value of heterosis in today’s beef industry pricing structure. Many producers are seeking ways to improve cow-calf production efficiency and profitability. Profitability may be enhanced by increasing the volume of production (i.e. the pounds of calves you market) and/or the value of products you sell (improving quality). The reduction of production costs, and thus breakeven prices, can also improve profitability. Better yet, improving the input:output ratio should enhance profit. For commercial beef producers, the implementation of technologies and breeding systems that increase the quality and volume of production and reduce input costs is essential to maintain or improve the competitive position of the operation. Some producers are thinking of establishing a more conventional straight breeding system to improve end-product value traits and want to understand the value they are giving up as they sacrifice heterosis, while other producers are considering the establishment of a planned crossbreeding system to capture the value of hybrid vigor. Either way, to make an informed decision, producers need to know the value generated in their herd by heterosis or hybrid vigor

Genotype by environment interactions for growth in Red Angus

Citation: Fennewald, D. J., Weaber, R. L., & Lamberson, W. R. (2017). Genotype by environment interactions for growth in Red Angus. Journal of Animal Science, 95(2), 538-544. doi:10.2527/jas2016.0846Accuracy of sire selection is limited by how well animals are characterized for their environment. The objective of this study was to evaluate the presence of genotype x environment interactions (GxE) for birth weight (BiW) and weaning weight (WW) for Red Angus in the United States. Adjusted weights were provided by the Red Angus Association of America. Environments were defined as 9 regions within the continental United States with similar temperature-humidity indices. Mean weights of calves were determined for each region and for each sire's progeny within each region. A reaction norm (RN) for each bull was estimated by regressing the sire means on the region means weighted for the number of progeny of each sire. The range for BiW and WW RN was -1.3 to 4.0 and -1.7 to 2.8, respectively. The heritabilities of BiW and WW RN were 0.40 and 0.39, respectively. Phenotypic and genetic correlations between BiW and WW RN were 0.19 and 0.54, respectively. The phenotypic correlation of the progeny mean to the RN was -0.20 (P < 0.05) and suggests that sires with higher means are more stable in progeny performance across environments. Weights in different regions were considered separate traits and genetic correlations were estimated between all pairs of regions as another method to determine GxE. Genetic correlations < 0.80 indicate GxE at a level for concern, but existed for only 2 of 36 estimates for BiW and 12 of 36 estimates for WW. Genetic correlations between different regions ranged from 0.74 to 0.96 for BiW and 0.62 to 0.99 for WW and indicate that sires tend to rank similarly across environments for these traits

Print Grades Prime: A quantitative analysis of producer communication preferences of U.S. beef breed association magazines through the lenses of uses, gratifications, and gatekeeping

The United States beef industry is a major stakeholder in national and international agriculture and is driven by technological innovations and beef producers in all 50 states. Beef cattle breed associations are essential to the success of the industry as they not only maintain breed pedigrees but also disseminate vital information to their members. The magazines of beef cattle breed associations are a primary source of communication for U.S. beef producers. Goals for this study were to determine what information beef producers use from their beef breed association magazines, what information they want to see more of in beef breed association magazines, and if producers prefer the magazines in a print or digital format. Uses and gratifications theory, which focuses on the reasons why individuals choose to use a specific communication medium; the effect the medium has on the individual; and the gratifications received through its use, guided this study, along with gatekeeping theory. We used a descriptive quantitative survey research design to disseminate a survey instrument to members of six U.S. beef breed associations. Results revealed a large percentage of survey respondents prefer their beef breed association magazines in a print format. Additionally, results indicate that respondents use association magazines for a variety of information, and they want to see more information related to breed improvement strategies, genetic selection, and technological advancements. Results revealed insightful uses of magazine topics related to breed associations and can be used as a resource to help guide the editorial content of the magazines. We recommend beef cattle breed associations continue to provide magazine content in both print and digital formats and include editorial topics curated to the needs of the beef producers using their magazines

Novel analysis of global DNA methylation in the limbic system of the bovine brain

Citation: Cantrell, B. A., McKay, S. D., Weaber, R. L., Funston, R. N., & Lachance, H. (2016). Novel analysis of global DNA methylation in the limbic system of the bovine brain. Journal of Animal Science, 94, 43-43. doi:10.2134/jas2016.94supplement443xThere has been limited research focusing on the genetic-environmental interactions in bovine brains. Global DNA methylation has been measured in brains of several species, but has yet to be examined in bovine. The objective of this study was to characterize global DNA methylation in 9 regions of the limbic system in the bovine brain: amygdala, bed nucleus of the stria terminalis, cingulate gyrus, dorsal raphe, hippocampus, hypothalamus, nucleus accumbens, periaqueductal gray, and prefrontal cortex. DNA was extracted from brain and blood samples of 6 Red Angus × Simmental steers (less than 20 mo of age), using the DNA Extraction Kit from Agilent Technologies (Santa Clara, CA) and a phenol chloroform extraction. Percent of global DNA methylation was determined using the MethylFlash Methylated DNA Quantification Kit (Colormetric) from Epigentek (Farmingdale, NY). Varying amounts of global DNA methylation were observed among the 9 functionally distinct regions of the bovine limbic system. Amygdala, bed nucleus of the stria terminalis, cingulate gyrus, dorsal raphe, periaqueductal gray, prefrontal cortex, and nucleus accumbens are all significantly different (P < 0.05) from 1 or more brain tissue type, using a paired t test in SPSS (IBM, Armonk, NY). Conversely, global DNA methylation of blood was not significantly different (P < 0.05) from any brain tissue type. This study shows significant differences in global DNA methylation among different tissue types in the limbic system of the bovine brain. Understanding the differences in global DNA methylation within different tissues in the brain will facilitate future research involving the effects of differential methylation with regard to economically important traits

Feet and Leg Traits are Moderately to Lowly Heritable in Red Angus Cattle

Objective: The goals of this study were to identify feet and leg indicator traits to be used in beef breed genetic evaluations and develop a scoring method that can be easily adopted by cattle producers. Description: Data were analyzed on 1,885 Red Angus cattle, and after editing, 1,720 records were used for analysis. Feet and leg phenotypes were obtained from August 2015 through September 2017 for 14 traits shown in the following table. Trained livestock evaluators collected measurements using an electronic tablet with offline data storage capabilities. Heritability estimates for all 14 traits were calculated from two different measurements of scale, the original 1-100 scale (1 and 100 are extreme, 50 is desirable), and scores truncated to a 1-9 scale (1 and 9 are extreme, 5 is desirable). Genetic parameters were estimated using maximum log likelihood procedures. The Bottom Line: Feet and leg traits are moderately to lowly heritable; however, producers can still select on traits for improved soundness. Scoring on a simpler, less granular measurement of scale (1-9) is appropriate to be used in further research

REVIEW: Life-cycle, total-industry genetic improvement of feed efficiency in beef cattle: Blueprint for the Beef Improvement Federation

On a life-cycle basis, beef animals are able to consume large amounts of low-cost, low-quality forages relative to higher-cost concentrates compared with pigs and chickens. However, of the 3, beef is still more expensive to produce on a cost–per–edible pound basis. Accordingly, there is need for genetic programs and management changes that will improve efficiency, sustainability, and profitability of beef production. Options include improving reproductive rate, reducing feed used for maintenance, or both, while not reducing output. A goal for improving efficiency of feed utilization is to reduce the amount or proportion of feed used for maintenance. Such reduction is a target for genetic improvement, but such a goal does not include defining a single measure of efficiency. A single efficiency measure would likely lead to single-trait selection and not account for any potentially antagonistic effects on other production characteristics. Because we are not able to explain all variation in individual-animal intake from only knowledge of BW maintained and level of production, measuring feed intake is necessary. Therefore, our recommendation is that national cattle evaluation systems analyze feed intake as an economically relevant trait with incorporation of appropriate indicator traits for an EPD for feed intake requirements that could then be used in a multiple-trait setting such as in a selection index. With improvements in technology for measurement of feed intake, individual measures of feed intake should continually be collected to facilitate development of genetic predictors that enhance accuracy of prediction of progeny differences in national cattle evaluations

Genetic parameters estimated at receiving for circulating cortisol, immunoglobulin G, interleukin 8, and incidence of bovine respiratory disease in feedlot beef steers

Citation: Cockrum, R. R., Speidel, S. E., Salak-Johnson, J. L., Chase, C. C. L., Peel, R. K., Weaber, R. L., . . . Enns, R. M. (2016). Genetic parameters estimated at receiving for circulating cortisol, immunoglobulin G, interleukin 8, and incidence of bovine respiratory disease in feedlot beef steers. Journal of Animal Science, 94(7), 2770-2778. doi:10.2527/jas2015-0222Bovine respiratory disease complex (i.e., shipping fever and bacterial bronchopneumonia) is a multifaceted respiratory illness influenced by numerous environmental factors and microorganisms. Bovine respiratory disease (BRD) is just one component of BRD complex. Because BRD is moderately heritable, it may be possible to reduce the incidence of BRD through genetic selection. The objectives of this study were to determine the heritability and associative genetic relationships among immune system traits (i.e., cortisol, total IgG, IgG isotypes, and IL-8) in cattle monitored for BRD incidence. At an average of 83 d after weaning (219 d age and mean = 221.7 kg [SD 4.34]), crossbred Bos taurus steer calves (n = 2,869) were received at a commercial feedlot in southeastern Colorado over a 2-yr period. At receiving, jugular blood samples were collected at 212 (yr 1) and 226 d (yr 2) of age for immune trait analyses. The BRD phenotype was defined as a binomial variable (0 = no and 1 = yes) and compared with immune system traits measured at receiving (prior to illness onset). An animal identified as BRD positive exhibited ? 2 clinical signs (i.e., eye or nasal discharge, cough, lethargy, rapid breathing, acute interstitial pneumonia, or acute upper respiratory syndrome and/or a rectal temperature &gt; 39.7°C). Heritability and genetic correlation estimates for categorical variable BRD, cortisol, IgG, IgG1, IgG2, and IL-8 were estimated from a sire model using ASREML. Heritability estimates were low to moderate for BRD (0.17 ± 0.08), cortisol (0.13 ± 0.05), IgG (0.15 ± 0.05), IgG1 (0.11 ± 0.05), IgG2 (0.24 ± 0.06), and IL-8 (0.30 ± 0.06). A moderate negative genetic correlation was determined between BRD and cortisol (rg = ?0.19 ± 0.32). Moderate positive correlations were found between BRD with IgG (0.42 ± 0.28), IgG1 (0.36 ± 0.32), and IL-8 (rg = 0.26 ± 0.26). Variation in the BRD phenotype and immune system traits suggested herd health improvement may be achieved through genetic selection. © 2016 American Society of Animal Science. All rights reserved

Genetic Variance and Covariance Components for Feed Intake, Average Daily Gain, and Postweaning Gain in Growing Beef Cattle

Feed is the greatest cost for a beef cattle production enterprise. Data collection to determine feed efficiency of animals is also costly, because both gain and intake records are needed to calculate feed efficiency. Electronic intake monitoring systems such as GrowSafe or Insentec to collect feed intake data are expensive and thus limit the number of animals that can be tested. Scientists have worked to pinpoint optimal test durations for collecting both weight gain and feed intake records to lessen costs. A 70-day performance test is currently recommended for accurate calculation of efficiency, with growth data as the limiting factor. Research has suggested that a 35-day test is adequate to measure feed intake, but a test period of at least 70 days is suggested to measure gain with sufficient accuracy. The objective of this study was to estimate genetic parameters for growth and intake traits with particular attention to the relationship between on-test average daily gain (ADG) and national cattle evaluation postweaning gain (PWG). If the correlation between these two traits is strong, it could allow for the use of PWG as a proxy for ADG in the genetic evaluation of feed efficiency. This substitution would allow producers to reduce the length of the test required to measure feed intake accurately

Bio-economic Model Predicts Economic Values for Beef Production

Objective: The objective was to estimate economic values for production traits in a full life cycle system using a bio-economic model with Angus purebred and a terminal crossbreeding system with Nelore sires mated to Angus dams. Study Description: Phenotypic performance data were collected from the Bifequali crossbreeding scheme at the Embrapa Pecuária Sul Research Center of the Brazilian Agricultural Research Corporation. The data consisted of performance and carcass traits measured on progeny of Angus purebred and Nelore sires mated to Angus dams raised in a pasture-based production system from birth to slaughter (full life cycle). The economic characterization of the system was based on fixed costs and variable costs. The bio-economic was developed in ‘R’ programming language using the phenotypic information and the production costs. To estimate economic values, the bio-economic model was first parameterized and a base profit was calculated. The Bottom Line: The use of crossbreed animals provides an effective tool to improve important traits and system level profitability in a full life cycle beef production system

Genetic relationships among temperament, immune function, and carcass merit

Cattle producers historically have selected for docile temperaments simply for management convenience because calmer animals are conducive to safe environments for their peers as well as their handlers. As many producers would acknowledge, there seems to be a relationship between temperament and health, and calmer cattle tend to frequent the working chute for treatment of disease less often. Positive correlations have been found in cattle between temperament traits (chute scores, pen scores, and chute exit velocities) and cortisol concentration in the blood, suggesting that more excitable cattle are easily stressed (Curley et al., 2006; Cooke et al., 2009). In addition, Curley et al. (2007) found that easily excitable animals sustain elevated cortisol concentrations for a longer duration and had greater pituitary and adrenal responses following a stressor than calm cattle. Temperamental cattle have significantly higher mean temperament responses at all points (Oliphint, 2006). Higher basal serum cortisol concentrations may suggest that easily excitable cattle are chronically stressed (Curley et al., 2007), possibly resulting in a compromised immune system, illness, and decreased fat and protein deposition. Common measures of cattle temperament are pen scores, chute scores, and exit velocities. Temperament appears to be moderately heritable, with estimates ranging from 0.15 to 0.44 (Burrow and Corbet, 2000; Kadel et al., 2006; Schrode and Hammack, 1971; Stricklin et al., 1980; Fordyce et al., 1988). If genetic correlations are found between temperament and production traits or immunological factors, they may aid cattle breeders in producing profitable cattle. Such relationships have been found between exit velocity and hot carcass weight (r = -0.54), exit velocity and marbling score (r = 0.10), exit velocity and yield grade (r = -0.22) (Nkrumah et al., 2007), and post-weaning weight gain and exit velocity (Weaber et al., 2006). Bovine respiratory disease (BRD) susceptibility has been estimated to be lowly heritable (Muggli-Cockett et al., 1992; Snowder et al., 2005, 2006, 2007; Schneider et al., 2008). This study was conducted to further investigate the genetic relationships between cattle temperament measured by chute score and exit velocity, immunological factors, and a range of economically relevant performance traits