Economic Selection Index Research Articles

Effects of genetic and environmental trends from 1970 to 2020 on farm efficiency estimated with a whole farm modeling system

The objectives of this study were to evaluate associations of genetic, cow management and nutrition, inbreeding, and crop yields from 1970 to 2020 with measures of production and economic efficiency according to a whole farm model, and to evaluate effects of genetic change in individual traits on economic efficiency in comparison to expectations from economic selection indexes. Genetic and phenotypic performance metrics for Holsteins from 1970 and 2020 were retrieved and input into the Integrated Farm System Model (IFSM) for a 7000 cow TX herd and a 50 cow PA grazing herd. Crop yields estimates from 1970 and 2020 were retrieved and farm hectarage was altered so that forage and energy concentrate requirements were met through farm production; likewise, scenarios evaluating effects of atmospheric CO2 fertilization (CO2F) on crop yield were evaluated by altering farm hectarage. For single traits that could be dynamically modeled by IFSM, performance shifts and resulting change in product prices or management expenses were added to 1970 base models. Economic efficiency was evaluated as the per cow return to management and unpaid factors as compared with 1970 base models. As averaged across state scenarios, gains in economic efficiency were +$945 and -$76 for additive genetic and inbreeding effects, respectively, for a total gain from genetic change of +$869. Genetic gain in fat yield (+$549) and protein yield (+$524) were responsible for most of the genetic gain, whereas milk yield (-$128) and increased cow BW (-$129) depressed economic efficiency. Genetic change in productive life had a smaller effect (+$44) than predicted unless heifers were purchased and at double the default value. Gains due to cow management and nutrition increased efficiency by +$666 and crop yield increased efficiency by +$711, of which +$371 was attributed to CO2F across scenarios. Whole farm dry matter efficiencies derived as the ratio of fat and protein corrected milk yield to dry matter intake increased from 0.82 (PA) and 0.97 (TX) in 1970 to 1.20 in 2020 and could be higher if farms reduce the size of their replacement herd by producing beef calves. The landmass required in 2020 was 63% and 78% of the 1970 requirement for TX and PA, respectively. Changes in cow genetic merit, management and nutrition, and crop yields have all increased the economic and environmental sustainability of milk production, and systems such as IFSM could be a useful tool to help inform economic selection indices.

Beef cattle mating recommendation based on bioeconomic models

Recognizing the pivotal role of mating in animal breeding, this study strives to establish a robust strategy for recommending optimal matings among bovines. This strategy is built to maximize a single value derived from the economic selection index of full-cycle system in Brangus cattle. The study endeavors to apply computational methodologies to explore economically significant traits comprehensively, thereby leading to amplified financial gains for Brangus cattle breeders. Anchored within this overarching objective, a strategic deployment of a genetic algorithm is employed to formulate mating recommendations that precisely align with the priority traits designated by the genetic evaluation program of the Brazilian Brangus Association (BBA). The data set of the BBA for the simulations in this study encompass a range of selection criteria, including: i) birth weight; ii) mature cow weight; iii) ribeye area; iv) subcutaneous fat thickness; v) subcutaneous fat thickness at the rump; vi) escape speed; vii) nematode egg count per gram of feces; and viii) tick count. The research findings underscore that the recommendations provided by the computational strategy converge to increase the bioeconomic index while controlling the trade-off between this index and progeny inbreeding.

Impact of planning horizon length on traits in an economic breeding goal and ranking of selection candidates in beef cattle

Abstract In beef production herds, unique situations such as breeding system, economic parameters, and current phenotypic performance can affect the emphasis of traits in the breeding goal and consequently the weighting of traits within a selection index. An often overlooked component of breeding goals is the planning horizon, or the time span to consider the economic impact of a selection decision, that varies between enterprises. A platform for constructing economic selection indexes (iGENDEC) was used to determine the impact of planning horizon length, breeding system, and sale endpoint on the relative emphasis of traits in the breeding goal and the re-ranking of selection candidates. As part of this investigation, the adjustment of phenotypic means for hot carcass weight and planning horizons were used to determine the impact of the relative emphasis on hot carcass weight as its mean approached a predetermined discount threshold. General-purpose indexes were created for animals sold at weaning and slaughter for three breeding systems with six different planning horizons (2, 5, 10, 20, 30, and 50 yr). As planning horizon increased, the relative emphasis on weaning weight or hot carcass weight, which affected revenue, decreased while the relative emphasis on stayability and mature weight increased. As the phenotypic mean for hot carcass weight approached and surpassed a predetermined discount threshold, the relative emphasis decreased before increasing again, once the mean weight surpassed the threshold. Rank correlations between indexes with different sale endpoints was 0.71 ± 0.1. Within a slaughter endpoint, re-ranking occurred between short and long planning horizons (r = 0.78 ± 0.09) while that of a weaning endpoint was less substantial (r = 0.85 ± 0.10). Jacard index scores between indexes with different planning horizons ranged from 39.7% to 87.9% and from 47.9% to 78.7% for weaning and carcass endpoints, respectively, for the top 5% of selection candidates. These results illustrate that the determination of a planning horizon can impact the rank of selection candidates and increases in net profit.

Grounding the economic selection index for evaluation and selection of dairy cattle

The aim of the research was to develop a selection index for the evaluation and selection of dairy cattle for increasing milk production and reproductive traits. Materials of the research were data on milk production and reproduction of cows of the Ukrainian Black-and-White dairy breed in commercial farm in Kharkiv region. Studies showed that there was a certain antagonism between milk productivity and reproduction of the Ukrainian Black-and-White dairy cow. The coefficients of phenotypic correlation between milk yield, fat and protein yield and the days open ranged from +0.284 to +0.293. Selection indexes were built, which included protein, fat yield, and days open. The developed selection indexes were characterized by a high relationship with the protein yield (α<0.001), much lower – with the fat yield (α<0.05), while the relationship of the selection indexes with the days open was almost absent. The calculated estimates of correlation and regression coefficients made possible to predict correlated responses of milk production and reproduction traits on selection index. The results showed that the developed selection indexes allow increase the milk production of cows and at the same time to prevent decrease in the level of reproduction.

41 Genetic Selection for Improved Profit Conditioned on Enterprise-Specific Circumstances

Abstract Circumstances of producers relative to objectives, economic constraints, and production environments differ substantially. Consequently, the specific path of sustainability differs among beef enterprises. Such a path must take a supply-chain approach, contemplating market (consumer) demands, and firm-level economic costs and returns in both the short- and long- term. Long-term economic returns imply longer-term stewardship of natural resources. Genetic selection is uniquely poised to aid in the pursuit of greater economic and biological efficiency, given it represents a cumulative and permanent source of change. However, it is critical that such change be consistent with the producer-specific sustainability path. Given there are multiple traits that impact economic outcomes economic selection indexes are the appropriate tool. The general form of such indexes has been around for about 80 years, albeit with a less than desirable adoption rate in beef selection decisions. The process of index development can account for known sensitivities to differences in marketing endpoints and current levels of phenotypic performance. Moreover, the time horizon used to determine the economic consequences of a selection decision could differ among enterprises. The choice of planning horizon (PH) is an important, yet often overlooked component of breeding objective and index construction. Shorter PH inherently emphasizes traits that can be fully expressed in the near term whilst longer PH allow more substantial weighting of traits expressed later in life. Misalignment of breeding objectives and selection indexes, as might be the case in using a terminal index to choose sires in a self-replacing herd, or incorrect choice of PH could lead to less profitable genetic selection decisions by increasing mature cow weight and/or de-emphasizing reproductive longevity. Consequently, our objective was to provide examples of how trait emphasis might be altered under different assumptions during selection index development using the web-based tool iGENDEC. Indexes assumed replacement females were retained and terminal animals were retained through harvest. We then compared changes in PH, annual cow variable costs, and phenotypic means of hot carcass weight (HCW). The combined relative emphasis (RE) of mature cow weight (MWT) and stayability (STAY) in the breeding objective was 0, 10, and 22% when planning horizon was 2, 10, and 20 years, respectively. As HCW increased from 318 to 408 kg the RE of STAY increased from 10.9% to 18.7% while the RE of HCW decreased from 43.8% to 28.9%. When annual cow variable costs were $250, $500, and $750 the RE of MWT was 6, 14.9, and 22.5%, respectively, assuming the value of calves sold stayed the same. Collectively, these examples illustrate that incorrect definition of breeding objectives and parametrization of indexes can lead to inappropriate weighting of traits that are drivers of long-term resource use (i.e., MWT and STAY).

A new angle on the bovine foot

Structural unsoundness of beef cattle is an important issue for producers and contributes to issues of lameness and injury that result in increased treatment, culling and death in the beef cow-calf segment. In recent years, utilization of structural scoring in the form of foot and leg phenotype scores as an evaluation tool for genetic evaluation to assess the structural conformation of beef cattle in many countries including the United States. The different breed organizations in the United States have devel­oped resources for breeders to assess and capture data related to foot and leg scores with utilization varying from within herd culling to expected progeny difference development and utiliza­tion within economic selection indexes. Awareness of structural scoring and associated resources by veterinarians as well as a baseline knowledge of utilization within genetic evaluations, management approaches and environmental risk factors that magnify structural unsoundness into lameness and injury events is an opportunity to provide valuable insight and direction to producers in the form of prevention and selection.

Evaluation of Zoetis GeneMax Advantage genomic predictions in commercial Bos taurus Angus cattle

The GeneMax (GMX) Advantage test, developed by Zoetis, uses approximately 50,000 single nucleotide polymorphisms (SNP) to predict the genomic potential of a commercial Angus heifer. Genetic predictions are provided for Calving Ease Maternal, Weaning Weight, Heifer Pregnancy, Milk, Mature Weight, Dry Matter Intake, Carcass Weight, Marbling, Yield, and three economic selection indices. Test results can inform selection and culling decisions made by commercial beef cattle producers. To measure the accuracy of the trait predictions, data from commercial Angus females and their progeny at the University of Missouri Thompson Research Center were utilized to analyze weaning weight, milk, marbling, fat, ribeye area, and carcass weight. Progeny phenotypic data were matched to the respective dam, then the cow's genomic predictions were compared to the calf's age-adjusted phenotypes using correlation and linear model effect sizes. All tested GeneMax scores of the dam were significantly correlated with and predicted calf performance. Our predicted effect sizes, except for fat thickness, were similar to those reported by Zoetis. In conclusion, the GeneMax Advantage test accurately ranks animals based on their genetic merit and is an effective selection tool in commercial cowherds.

Valuation of Genomic-Enhanced Expected Progeny Differences in Bull Purchasing

AbstractWe estimate a hedonic pricing model to determine producers’ value for bull expected progeny differences (EPDs), genomic-enhanced EPDs, and phenotypic traits. Birth weight EPD, ribeye area EPD, sale weight, age, frame score, and other factors had a statistically significant impact on bull prices. GE-EPDs were not associated with a change in the bull sales prices expect for weaned calf value and birth weight EPDs. Including weaned calf value and GE-EPDs in a bull hedonic pricing model provides a unique contribution. The results from this work will inform educational programming for bull purchasers on using new economic selection indices and GE-EPDs.

Genetic selection of Nellore cattle raised in tropical areas: Economic indexes and breeding decisions risks

Different selection indexes (Index I [Optimal], Index II [Maternal], and Index III [Terminal]) were evaluated in a full-cycle, pasture-based production system of Nellore cattle. The economic selection indexes consisted of combinations of the traits: body weight at 120 (W120), 210 (W210), 365 (W365), and 450 days (W450) of age; age at first calving (AFC); calving interval (CI); scrotal circumference at 365 (SC365) and 450 (SC450) days of age; ribeye area (REA); subcutaneous fat thickness (FAT); stayability (STAY); and accumulated productivity (ACP). Bootstrap analyses were performed to assess the distribution of the response to the optimal index by changes in the economic value of traits and the impact caused by each economic trait. The implementation of the optimal index and the adjustment of the expected return for uncertainty in the prediction of breeding values were carried out with 67 sires. The most genetic-economic important traits were W450, AFC, ACP, and REA. Index I showed the greatest economic response to selection (R$ 938.95/generation), followed by Indexes II (R$ 811.84) and III (R$ 476.26). Economic response variations of Index I ranged from R$ 100.71 to R$ 1747.43. The highest contributions and range of economic response were observed in ACP, followed by W450, and CI. Sires ranking changed ± 4.0 positions with adjustment for risk in Index I, indicating changes in breeding decisions when selecting sires. All indexes presented great efficiency and can be adapted to similar production scenarios that expect a similar overall gain. Adjustment for risk in the selection index should be considered for optimal breeding decisions.

Selection indexes to optimise genetic and economic progress in Colombian Blanco Orejinegro cattle

The use of selection indexes optimises genetic and economic gains in a population. The objective of this study was to propose and compare selection indexes built with economic and statistical methodologies in Colombian Creole Blanco Orejinegro breed. Genetic, phenotypic and economic information of the breed were used to design and test the selection indexes. The weights of each selection criteria (weight at 24 months of age, age at first calving, calving interval) were estimated using phenotypic variances, eigenvectors from a principal component analysis and economic values obtained through a deterministic bio-economic model. The selection criteria with the highest weight was weight at 24 months of age, with values of 0.56 and 0.034 USD using eigenvectors and phenotypic variance, respectively. The calving interval had the highest weight using the bio-economic model, with a value of -1.3 USD. The greatest profit due to genetic selection was obtained using the economic values as weights, which increased the average expected profit to a value of 18.76 USD/cow/year. The selection indexes calculated from phenotypic and eigenvectors do not rank animals similarly to the economic selection index. It could generate less genetic and economic progress in the national selection programme for the Blanco Orejinegro breed.

Conformation traits of Holstein cows and their association with a Canadian economic selection index

Pro$ is a Canadian economic selection index aimed to maximize profit by increasing production yields, while maintaining conformation and functional traits. Currently, there is an interest in understanding the individual contributions of conformation traits recorded in Canada to the overall economic value of a cow and whether they are equally important. We used multiple polynomial regression and principal component analysis to assess the association of 26 conformation traits with Pro$ using relative breeding values (RBVs) from 9351 proven bulls. The best reduced regression model explained 72.5% of the variance in Pro$, with heel depth and body depth having the highest and lowest effect on Pro$ values, respectively. Four traits classified as intermediate optimum traits, e.g., teat length, showed significant linear association with Pro$ instead of quadratic, whereas bone quality was not significantly associated with the index. Principal component analysis indicated that highly profitable bulls share similar RBV, with a subclustering of bulls of daughters with better mammary system versus better dairy strength and feet and legs. These results provide understanding of the individual contributions of conformation traits to Pro$ and give information to guide the Canadian dairy industry on how to best consider these traits in recording and genetic evaluation programs.

41 Genomic Approaches to Improving Forage-based Beef Cow Efficiency

Abstract In recent decades, the U.S. beef herd has seen massive gains in efficiency, driven by innovations in genetics, nutrition, reproduction, and resource management. Despite these advances, the industry remains under pressure to further reduce its environmental footprint. Perhaps the greatest opportunity to drive increases in sustainability is through targeted genetic improvement of forage-based cow-calf systems. While the industry has long focused on selecting for pre- and post-weaning performance, improvements in mature cow efficiency are more challenging to attain. One major impediment to directly selecting for cow efficiency is a lack of easily measured indicator phenotypes, leading some segments of the industry to focus exclusively on moderating mature size. The optimal solution to this problem will likely require a more complex understanding of the underlying biology of cow efficiency. As we consider how genomics might increase the environmental sustainability of forage-based beef production, we will need to focus on developing and measuring novel phenotypes and accounting for the complex interplay between an animal’s genetics, environment, and management. Using stochastic genetic simulations, we demonstrate the potential environmental and economic impacts of genetic selection for more efficient and well-adapted cows. We also describe possible solutions for measuring a cow’s efficiency on grass (e.g., forage intake to weaned calf pounds) that could be used to develop novel EPDs and economic selection indexes. Finally, we discuss the concept of precision genomic predictions that account for how genotypes interact with environmental stressors and management differences. We propose two potential solutions to address this concern: 1) Selecting robust cattle that perform well across all environments and management levels or 2) Developing precision predictions for precisely matching animals to their ideal production scheme.

Multi-trait selection index and cluster analyses in Angus cattle

AbstractIn breeding programmes, the genetic selection process is based on the prediction of animal breeding values, and its results may vary according to the employed selection method. The current study developed an economic selection index for animals of the Angus breed; performed cluster analyses using the breeding values in order to evaluate the genetic profile of the animals candidates to selection, and compared the obtained results between the economic selection index and the cluster analyses. The evaluated traits included weaning weight, 18-month weight, scrotal circumference, fat thickness and ribeye area. Economic values were obtained using bioeconomic modelling, simulating a complete cycle production system of beef cattle breeds in Brazil, and the selection objective were the weaning rate and slaughter weight. The chosen selection index was composed of all of the traits used as selection criteria for the simulated production system. During the cluster analyses, the population was divided into two to four groups, in which the groupings containing potential animals were assessed. The animals of the grouping which was used for comparison with the selection index were identified, and most of the bulls that were included in the index were among the best in the analysed group. These results suggest that the cluster analyses can be used as a tool for the selection of animals to be used as parents for future generations.

Estimation of economic value for efficiency and animal health and welfare traits, teat and udder structure, in Canadian Angus cattle.

The Canadian Angus Association recently developed genetic evaluations for teat and udder structure, which impact efficiencies, and animal health and welfare. Genetic selection tools are most effective incorporated into economic selection indexes. An important factor in the development of economic indexes is the estimation of the economic value and discounted gene expression coefficients, and thereby the economic weight, of each trait. Traditional estimation methods, interrogation of previous studies quantifying the impact of the traits and bioeconomic modelling, were reinforced using producer surveys that employed pairwise ranking methods. Estimates of discounted genetic expression coefficients, economic value and economic weight for teat and udder score in Canadian Angus cattle were 0.31 per sire, $52.47, and $16.91 per score change on a per calf born basis, respectively, indicating that functional traits such as teat and udder structure have a significant impact on profitability and should be included in genetic selection programmes. Limitations in previous studies illustrate the need for longitudinal studies on traits that impact efficiencies and animal health and welfare.

90 Effectiveness of an Educational Program on Beef Bull Selection that Incorporates Classroom Instruction and a Mock Auction

Abstract An educational program was developed to assist beef producers with making informed bull purchasing decisions. There are two core pieces to this decision: targeting the bull’s genetics to the producer’s management and resources, and paying a price that maximizes the return on investment. This was a two-part educational program; the first session was classroom instruction with topics related to proper bull selection. At the conclusion of this session producers were assigned one of five management scenarios and received a sale catalogue with 60 bulls. Videos of all bulls were made available, along with all production information, including adjusted measurements, EPD and indices. The producers were tasked with returning the next week to attend the mock auction and purchase the best valued bull for their assigned scenario. At the conclusion of the auction, each scenario was discussed and the individual that purchased the best value bull in each scenario was recognized. Value was determined as the price paid for the bull compared to a price determined through an “economic selection index” equation. Beef producers (n = 322) participated in the program over 9 locations; in locations with less attendance, a reduced sale catalogue was used. Of the post-program survey respondents (n = 155), 71% were commercial beef producers, 27% were seedstock producers and 5% were Extension agents (n = 10, were cross classified). When asked how much time they spent reviewing the materials before the mock sale 8% said they made their decision at the sale, 16% spent 30 minutes or less, 58% spent 30 minutes to 2 hours and 18% spent over 2 hours preparing. When asked if the program would help with their next bull purchase, 88% said it would probably or definitely help. The conclusion was that this was a valuable educational program.

Economic values for index improvement of dual-purpose Simmental cattle

The selection index methodology is the best approach to increase profit in animal production by genetic selection due to the use of economic values for breeding goals. The aim of this study was to derive economic values through a deterministic bio-economic model in order to construct an economic selection index for dual-purpose Simmental cattle. Phenotypic, genetic and economic information from the Colombian Simmental genetic evaluation were used in this investigation to design a base production system. The economic values for weight at eight months of age, age at first calving, first lactation milk yield and first calving interval were obtained by calculating the partial derivatives of farm profit with respect to each trait, the relative economic importance for each trait was 43.45, 15.29, 5.33 and 35.93%, respectively. By increasing the selection index by one dollar, the milk yield contributed the most to genetic gain with an increase of 10.36 L, while the lowest genetic gain was found for the weight at eight months of age with an increase of 0.088 kg. The milk yield had the greatest economic contribution worth 0.642 dollar for each USD of increase in the index. The economic values and the final selection index provided favorable genetic and economic progress for milk, beef and reproductive traits in Simmental cattle under tropical conditions. Likewise, estimated economic values can be used to make decisions on the selection of foreign bulls to similar Simmental production systems.

The value of incorporating carcass trait phenotypes in terminal sire selection indexes to improve carcass weight and quality of heavy lambs

Genetic selection for carcass traits is paramount to maximize the profitability and long-term sustainability of any meat-producing livestock species. The main objectives of this research were to evaluate the efficiency of indicator traits for the genetic improvement of lamb carcass traits and to determine the value of including carcass traits into terminal sire selection indexes for the Canadian sheep industry. The carcass traits included hot carcass weight (HCW), fat depth at the GR site (FATGR) and average carcass conformation score (AVGCONF), and were measured on heavy lambs (slaughter age less than 365days and HCWgreater than 16.3kg) in commercial abattoirs. Growth traits were found to be moderately efficient indicator traits for the genetic improvement of HCW but selection on ultrasound traits was necessary to substantially improve the carcass quality traits (FATGR and AVGCONF). Economic selection indexes were designed by adding various combinations of carcass traits into the Canadian Sheep Genetic Evaluation System terminal indexes. Records measured on individuals and progeny were assumed to be the sources of information for live animal and carcass traits, respectively. The changes in index accuracy, efficiency and expected correlated response were used to assess the value of their inclusion. HCW was found to have a large economic value, and its inclusion into terminal selection indexes was expected to substantially increase their accuracy (0.08-0.12 points) and efficiency (20%-30%). However, further including FATGR (measured 110mm from the carcass midline over the 12th rib) and AVGCONF had little impact on the accuracy (≤0.03) and efficiency (1%-7%) of the proposed indexes. Thus, the inclusion of carcass traits into the existing terminal selection indexes could be beneficial for the genetic improvement of HCW, but further research is needed to determine optimal methods of increasing carcass fatness and muscularity.

Economic selection index to improve fiber quality in Mongolian Cashmere goats

The objectives of this study were (i) to identify indicator traits that facilitate selection for decreased fiber diameter and (ii) to quantify the difference of aggravated genetic responses of an economic selection index applied to simultaneously favor reduced fiber diameter and increased cashmere fleece weight in indigenous cashmere goats in Mongolia. The accuracy of prediction by indicator traits and their combinations were compared to predict the economically relevant traits fiber diameter and cashmere fleece weight using a Best Linear Prediction method. Direct selection for fiber diameter resulted 0.39 µm decrease in fiber diameter, however, cashmere fleece weight hardly changed (-2.90 g) per generation. In contrast, using all traits in selection criteria, fiber diameter expected to decrease by 0.41 µm per generation due to the enhanced accuracy of prediction. The conclusion of this study was (i) estimated breeding values should be developed for fiber diameter, a major determinant of cashmere price, for every breeding buck and doe and (ii) economic selection indexes could simultaneously improve two genetically antagonistic and economically relevant traits in cashmere production system.

Economic Importance of Genetic Improvements in Milk Production, Reproduction, and Productive Life

Florida dairy producers have access to genetic evaluations for many dairy traits that are economically important. These traits are combined in economic selection indexes to rank bulls and cows for total profitability. The first economic selection index, introduced in 1971 by the USDA-Animal Improvement Programs Laboratory (USDA-AIPL) in Beltsville, MD, included only milk and fat yield. But other traits, such as the ability to get pregnant in time or to avoid culling, determine a cow's profitability as well. This document is AN158, one of a series of the Animal Science Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date November, 2005.

Economic Selection Indices: The Best Tool for Dairy Cattle Selection

An economic selection index combines multiple traits into a single value, facilitating the identification of the best animals. This new 3-page document discusses economic selection indices, their changes in the US, and a 2018 update. Written by Francisco Peñagaricano, and published by the UF/IFAS Department of Animal Sciences, March 2019. http://edis.ifas.ufl.edu/an353