Progress 10/01/07 to 09/30/09
Outputs
OUTPUTS: Research completed under this project was published in refereed journals, and presented in various extension venues. All publications are available in print as well as via the internet. PARTICIPANTS: M.W. Tess - PI R.E. Kruse, V.L. Reisenauer Leesburg, K.C. Davis, K.I. Neary - research associates R.K. Keitschmidt, D. Griffith, E.E. Grings, J. W. Boles, R.E. Short, W.A. Phillips, H.S. Mayeux, D.L. Boss - collaborators Partner organizations = Montana State University, USDA-ARS-LARRL Fort Keogh, American Simmental Association, USDA-ARS-USMARC. TARGET AUDIENCES: Target audiences = beef cattle producers in the Northern Great Plains, students, natural resource managers, extension educators, and scientists. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
This research addressed several practical beef cattle management issues, especially relevant to producers in the Northern Great Plains. Evaluations of predictors of forage production based on climatic data indicated that annual forage production may be estimated with confidence by July 1; implying that drought management decisions can be made at that time. Early-season drought detection provides flexibility devising management alternatives. In moderate or severe drought, when detected and implemented by July 15, early weaning of spring-born calves and feeding stored/purchased forages in a drylot was more profitable than normal weaning and supplementing dams. In beef operations with a restricted grazing season, limited access to low-cost, high-quality grazeable forage, and with calves sold at weaning, switching from early spring to a summer or fall calving date is not expected to improve profitability. When producers consider various retained ownership scenarios for weaned calves, no single combination of calving season and calf marketing is expected to be superior throughout the cattle cycle. Fall calving systems most often benefit from retained ownership through slaughter. Retained ownership must be treated as a separate enterprise from cow-calf production. Under some circumstances, late spring calving offers promise as a means to decrease feed costs and increase profits. Availability of low-cost forage is a key variable for cow-calf systems. Profits from retained ownership depend on the value of calves at weaning, postweaning costs of gain, and market prices at the end of the feeding period. Transportation and feed costs are critical postweaning variables. Molecular-genetic technologies are advancing at a rapid pace. DNA-based genotyping offers great promise in accurately identifying breeding value at an early age. For traits that can be measured under field conditions, it's critical that DNA-based information be appropriately combined with phenotypic data and pedigree records in the computation of breeding values. For all traits and information sources, it's important that breeding values be expressed in the units of the trait with corresponding accuracy values. The beef industry appears to be adopting these recommendations. Predicted feed intake for Simmental x Angus steers utilizing the Decision Evaluator for the Cattle Industry, developed at the U.S. Meat Animal Research Center (USMARC) appears to be moderately genetically correlated with actual feed intake. Actual feed intake is moderately correlated with several commonly measured traits. Our results suggest that breed associations will be able to use indexes of several production traits to economically predict breeding values for feed intake - i.e., without actually measuring feed intake. This is an important finding for the beef industry.
Publications
- Kruse, R. E., M. W. Tess, and R. K. Heitschmidt. 2007. Livestock management during drought in the Northern Great Plains. I. A practical predictor of annual forage production. Prof. Anim. Sci. 23:224-233.
- Kruse, R. E., M. W. Tess, and R. K. Heitschmidt. 2007. Livestock management during drought in the Northern Great Plains. II. Evaluation of alternative strategies for cow-calf enterprises. Prof. Anim. Sci. 23:234-245.
- Reisenauer Leesburg, V. L., M. W. Tess, and D. Griffith. 2007. Evaluation of calving seasons and marketing strategies in Northern Great Plains beef enterprises. I. Cow-calf systems. J. Anim. Sci. 85:2314-2321.
- Reisenauer Leesburg, V. L., M. W. Tess, and D. Griffith. 2007. Evaluation of calving seasons and marketing strategies in Northern Great Plains beef enterprises. II. Retained ownership systems. J. Anim. Sci. 85:2322-2329.
- Kruse, R.E., M.W. Tess, E.E. Grings, R.E. Short, R.K. Heitschmidt, W.A. Phillips, and H.S. Mayeux. 2008. Evaluation of Beef Cattle Operations Utilizing Different Seasons of Calving, Weaning Strategies, Post-weaning Management, and Retained Ownership. Prof. Anim. Sci. 319-327.
- Boles, J. A., D. L. Boss, K. I. Neary, K. C. Davis, and M. W. Tess. 2009. Growth implants reduced tenderness of steaks from steers and heifers with different genetic potentials for growth and marbling. J. Anim. Sci. 87:269-274.
- Tess, M. W. 2010. Guidelines for Combining Molecular and Quantitative Approaches in Genetic Evaluation. In Guidelines for Uniform Beef Improvement Programs. 9th Ed. In press.
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: Progress Report Research into the molecular basis of inheritance is progressing at a rapid pace. Technologies that permit the identification of molecular genetic differences are also evolving very rapidly. Several DNA-based tools are being marketed in the beef industry; some as selection tools. These tools are known by a variety of names in the academic community and within the beef industry (e.g., genomic tests, DNA markers, molecular tests or markers). DNA-based selection tools present opportunities and challenges to the U.S. beef industry. Accurate DNA-based selection tools will give beef cattle breeders opportunity to identify animals with superior breeding value (BV) as soon as a tissue sample can be collected and analyzed, potentially leading to significant savings in time and money associated with performance testing and genetic evaluation. However, as currently marketed, the BV information provided by DNA-based tools is not uniformly reported and the proportion of variation in true BV accounted for by the tools is unknown. Further, the BV information provided by competing DNA-based tools overlaps and is not independent of information provided by current national cattle evaluation (NCE) systems. Working under the direction of the Beef Improvement Federation (BIF), guidelines were developed for the incorporation of genomic marker information into NCE in the U.S. beef industry. Key components of this cooperative plan include breed specific resource populations that are linked to industry populations, national databases for the marker information, and the development of statistical methods for the melding of marker information with pedigree and performance information. The plan requires the cooperation of many segments of the beef industry. Formal guidelines were submitted to BIF. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Impact National cattle evaluation that optimally integrates breeding value information from all sources will yield more accurate estimates of breeding value at younger ages. Wise and informed selection decisions by beef cattle breeders throughout the industry depend on the success of this effort.
Publications
- Kruse, R.E., M.W. Tess, E.E. Grings, R.E. Short, R.K. Heitschmidt, W.A. Phillips, and H.S. Mayeux. 2008. Evaluation of Beef Cattle Operations Utilizing Different Seasons of Calving, Weaning Strategies, Post-weaning Management, and Retained Ownership. Prof. Anim. Sci. 319-327. 2008.
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: In recent years, advances in feeding technology have allowed for the collection of feed intake data; yet, these systems are unlikely to be used outside of research settings. Because EPD traditionally depend on data collected by beef producers in commercial settings, there is a need to identify indicator traits that can account for significant amounts of the genetic variation in feed intake. These indicator traits must be practical to measure so that they can be included in the computation of EPD for feed intake or feed efficiency. Data from individually fed Angus and Simmental x Angus steers will be used in this project. The Decision Evaluator for the Cattle Industry, developed at the U.S. Meat Animal Research Center will be used to predict dry matter intake (DMI) based on performance and attribute data collected on steers. Actual DMI recorded will be regressed on predicted DMI to evaluate the phenotypic predictive ability of the models. Estimates of (co)variance components,
heritabilities, and genetic correlations will be computed among the traits recorded, including predicted and actual DMI using mixed-model methods. We will determine the amount of genetic variation in feed intake explained by the simulation model, and evaluate the models' ability to genetically rank sires based on progeny performance.
PARTICIPANTS: M. W. Tess R. E. Kruse - graduate research associate V. L. Resienauer-Leesbury - graduate research associate R. K. Heitschmidt - USDA-ARS, LARRL, Miles City, MT D. Griffith - Department of Agricultural Economics and Economics E. E. Grings - USDA-ARS, LARRL, Miles City, MT C. Williams - USDA-ARS, USMARC, Clay Center, NE L. Berger - Animal Science Department, University of Illinois W. Shafer - American Simmental Association
TARGET AUDIENCES: Beef Cattle Breed Associations Beef Cattle Producers Efforts include publications, extension presentations, participation in Beef Improvement Federation activities, and direct communication with breed associations.
Impacts
If the simulation model is able to accurately account for the genetic variation among sires in feed intake, it's feasible that the model could be used to characterize progeny in commercial feedlots. In turn, the predicted DMI from these progeny could be used to compute EPD for sires; hence providing a cost-effective way of estimating breeding values for feed intake.
Publications
- Kruse, R. E., M. W. Tess, and R. K. Heitschmidt. 2007. Livestock management during drought in the Northern Great Plains. I. A practical predictor of annual forage production. Prof. Anim. Sci. 23:224-233.
- Kruse, R. E., M. W. Tess, and R. K. Heitschmidt. 2007. Livestock management during drought in the Northern Great Plains. II. Evaluation of alternative strategies for cow-calf enterprises. Prof. Anim. Sci. 23:234-245.
- Reisenauer Leesburg, V. L., M. W. Tess, and D. Griffith. 2007. Evaluation of calving seasons and marketing strategies in Northern Great Plains beef enterprises. I. Cow-calf systems. J. Anim. Sci. 85:2314-2321.
- Reisenauer Leesburg, V. L., M. W. Tess, and D. Griffith. 2007. Evaluation of calving seasons and marketing strategies in Northern Great Plains beef enterprises. II. Retained ownership systems. J. Anim. Sci. 85:2322-2329.
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Progress 01/01/06 to 12/31/06
Outputs
Production data from a 3-yr study were utilized to evaluate impacts of season of calving, weaning strategy, and retained ownership of steer calves on enterprise profitability. Calving seasons evaluated were late winter (LW; average = Feb 8), early spring (ES; average = Apr 5), or late spring (LS; average = May 31). Each calving season had two weaning times: 190 (LW190, ES190) or 240 (LW240, ES190) d for LW and EW, and 140 (LS140) or 190 (LS190) d for LS. Backgrounding options included shipping steers to OK (OK1), or backgrounding in MT to a constant age (MT2) or weight (MT3). Steers from OK1 and MT2 were finished in OK in confinement (C) or via a self-feeder on pasture (P) and harvested in TX. Steers in MT3 were finished in MT in C and harvested in CO. Production systems were modeled by year to characterize each possible combination of factors. Economic performance of each system was based on animal performance, market prices, and variable input costs. Gross margin
per cow were highest for LS190 (P < 0.05) and lowest for LW240. During backgrounding cost of gains were similar among cow-calf systems, while gross margins per steer were highest for LS140, but not different among backgrounding systems. During finishing cost of gains were highest for steers from MT2 due to transportation costs to OK, and gross margin per steer favored MT3. Gross margin for a ranch enterprise with a fixed land base did not differ among cow-calf systems if calves were sold at weaning, but was highest for LS systems after backgrounding or finishing (P < 0.05).
Impacts
Many cow-calf producers consider changes in calving season either to increase fall calf weights or to more closely match nutrient requirements to the available forage quality. For producers in the Northern Great Plains with resources similar to those available in this study, late spring calving offers promise as a means to increase profit. The decision to retain ownership of steer calves past weaning should consider several variables, especially the value of calves at weaning, expected costs of gain, and expected market prices at the end of the feeding period. Transportation and feed costs are critical variables affecting the costs of gain in retained ownership enterprises.
Publications
- Kealey, C.G., M.D. MacNeil, M.W. Tess, T.W. Geary and R.A. Bellows. 2006. Genetic Parameter Estimates for Scrotal Circumference and Semen Characteristics of Yearling Line 1 Hereford Bulls. J. Anim. Sci. 84:283-290.
- Anderson, D. C., M. W. Tess, K. C. Davis, D. L. Boss, and D. D. Kress. 2006. Breed of the dam effects on carcass traits and shear force of beef cattle. Proc. WSASAS 57:71-73.
- Torstenson, W.L.F., J.C. Mosley, T.K. Brewer, M.W. Tess, and J.E. Knight. 2006. Elk, Mule Deer and Cattle Foraging Relationships on Foothill and Mountain Rangeland. Rangeland Ecol. Manage. 59:80-87.
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Progress 01/01/05 to 12/31/05
Outputs
Objectives of this research were to: 1) evaluate the effects of estrous synchronization programs on enterprise profitability in Northern Range cow-calf operations and 2) identify optimum protocols, if any exist. A computer model of range beef production was developed to address these objectives. A northern range cow-calf production unit was simulated, applying estrous synchronization to either none of the herd, only yearling heifers, or both yearlings and mature cows. Breeding value between artificial and natural service sires were assumed equal. Protocols evaluated were: one-injection PGF system, two-injection PGF system, MGA/PGF, Select Synch, CO-Synch, and CIDR/PGF. The length of breeding season was either 45 or 66 d. Relative to natural service, calving percentage in the early period of calving season, calf weaning weight and age, herd pregnancy rate, and number of pregnant cows sold were increased by applying estrous synchronization. Production costs were
increased due to added costs of estrous synchronization; however, costs associated with bulls were reduced and increased revenue covered the cost for estrous synchronization and produced added profit. Hence, depending on protocols applied, estrous synchronization with artificial insemination could be more profitable than natural service. As a heifer protocol, MGA/PGF was best among those studied, and for mature cows, protocols that induce cyclicity in anestrous cows were most beneficial. Estrous synchronization can help producers achieve a short breeding season and increase profitability over and above that possible via genetic improvement through artificial insemination.
Impacts
Estrous synchronization protocols are used to manipulate the estrous cycles of beef cows in order to make artificial insemination (AI) easier to apply. Estrous synchronization with AI does affect the biological and economical efficiency of the Northern Range cow-calf operations. Reduced expenses associated with bulls and increased revenues associated with increasing calf weaning weight, herd pregnancy rate, and the number of pregnant cows sold can more than cover the increased production costs for estrous synchronization with AI. Hence, depending on the protocols applied, net profit would be equal to or higher than that of natural service management. These benefits are more apparent in a short breeding season management (45-d) than in the long season (66-d) and do not account for the potential superior breeding value of sires available through AI.
Publications
- Kealey, C.G., M.D. MacNeil, M.W. Tess, T.W. Geary and R.A. Bellows. 2006. Genetic Parameter Estimates for Scrotal Circumference and Semen Characteristics of Yearling Line 1 Hereford Bulls. (In Press).
- Davis, K. C., M. W. Tess, J. M. Rumph, R. P. Ansotegui, H. C. VanWaggoner. 2005. Reproduction traits and calf performance of first calf heifers sired by bulls with high marbling or high retail product EPD. Proc. WSASAS 56:102-104.
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Progress 01/01/04 to 12/31/04
Outputs
Objectives of this research were to estimate heritabilities of scrotal circumference and semen traits, and genetic correlations between these traits and birth weight. Line 1 Hereford bulls (n = 841), born in 1963 or from 1967 to 2000, were selected either for use by USDA-ARS at Miles City, Montana or for sale. Semen was collected by electro-ejaculation when the bulls were approximately one year of age (mean = 446d) and all samples were evaluated by one person. Traits analyzed were scrotal circumference, volume, concentration, motility, and percents normal, live, and primary and secondary abnormalities. Primary abnormalities were abnormal heads, abnormal mid-pieces, and proximal droplets. Secondary abnormalities were bent tails, coiled tails, and distal droplets. Data were analyzed using MTDF-REML. The model included fixed effects for contemporary group and age of dam, covariates for age of bull at evaluation and inbreeding of the bull and his dam, and random animal
and residual effects. Random maternal effects were also included for birth weight. Heritability estimates for birth weight, scrotal circumference, volume, concentration, motility, and percents normal, live, and primary and secondary abnormalities were 0.46, 0.57, 0.09, 0.16, 0.22, 0.34, 0.23, 0.09, and 0.13, respectively. Estimates of genetic correlations between birth weight and scrotal circumference, volume, concentration, motility, and percents normal, live, and primary and secondary abnormalities were 0.36, 0.07, 0.58, 0.21, 0.20, 0.34, -0.25, and 0.05, respectively. The moderate estimates of heritability for many of the traits indicate potential for favorable selection response. Positive genetic correlations between birth weight and majority of the traits suggest selection to reduce birth weight may compromise semen traits. However, for most traits the expected correlated responses are small.
Impacts
The moderate heritability estimates for scrotal circumference and most of the semen traits evaluated, imply improvement in these traits can be achieved through genetic selection. The genetic correlations between birth weight and semen characteristics indicate that there may be some negative impacts on bull fertility if selection for low birth weight is practiced.
Publications
- Kruse, R. E, M.W. Tess, E.E. Grings, R.E. Short, R.K. Heitschmidt, W.A. Phillips, and H.S. Mayeux. 2004. Evaluation of beef cattle operations utilizing different seasons of calving, weaning strategies, post-weaning management, and retained ownership. Proc. WSASAS 55:122-125.
- Kealey, C. G., M. D. MacNeil, M. W. Tess, T. W. Geary, and R. A. Bellows. 2004. Genetic parameter estimates for yearling scrotal circumference and semen traits of Line 1 Hereford bulls. Proc. WSASAS 55:36-39.
- J. A. Boles, K. C. Davis, D. Boss, K. Clawson, and M. W. Tess. 2004. Growth implants affect tenderness of beef steaks. Proc. WSASAS 55:226-229.
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Progress 01/01/03 to 12/31/03
Outputs
This research evaluated the impact of season of calving (SOC), weaning strategy (W), post-weaning management of replacement heifers (PWM), and retained ownership (RO) on enterprise profitability. SOC evaluated were late winter (Feb), early spring (Apr), and late spring (Jun). Feb and Apr calves were weaned at 6- and 8-mo of age; Jun calves were weaned at 4- and 6-mo of age. PWM strategies included one treatment intended to allow heifers to grow at a constant rate from weaning to breeding and the second intended to minimize harvested feed inputs. RO options included backgrounding and finishing in El Reno, OK (1), backgrounding in Miles City, MT, and finishing in El Reno, OK (2), and backgrounding and finishing in Miles City, MT (3). The data utilized were collected during a 3-yr study conducted at the Fort Keogh Livestock and Range Research Laboratory near Miles City, MT. Production systems were modeled to characterize each possible combination of factors (n=60).
Economic performance of each system was based on animal performance and variable cost inputs. Point estimates of animal performance were used regardless of statistical significance. Systems were analyzed at each level of production (cow-calf, backgrounding, and finishing). There were no differences between systems utilizing the different PWM. For cow-calf enterprises selling calves at weaning, the Jun late-weaned system yielded higher ranch gross margin (RGM = gross revenue minus variable costs) than all other systems (n=6), and the Apr early-weaned system was lowest. All other systems were not statistically different. When steer calves were backgrounded after weaning, few differences were found among possible backgrounding scenarios (n=18), and Jun calving remained superior to other seasons. When steer calves were retained to slaughter, finish option 1 had higher cumulative gross margin than options 2 or 3 in all SOC.
Impacts
Many cow-calf producers consider changes in calving season either to increase fall calf weights or to more closely match nutrient requirements to the available forage quality. Retained ownership options may also be considered as options to increase profitability. For producers in the Northern Great Plains, managing ranches similarly to these systems, June calving offers promise as a means to increase profit.
Publications
- Kruse, R. E., M. W. Tess, R. K. Heitschmidt, J. A. Paterson, and B. F. Sowell. 2003. Evaluation of drought management strategies for cow-calf operations. J. Anim. Sci. 81(Suppl. 1):20.
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Progress 01/01/02 to 12/31/02
Outputs
This research addressed the hypotheses that 1) spring precipitation data can be used to detect drought early in the growing season and 2) manipulating management strategies based on early detection of drought can have a positive effect on enterprise profitability. The Rangetek range model was used to simulate yearly forage data based on historical precipitation and temperature records from the Fort Keogh USDA-ARS Station near Miles City, Montana and the Manyberries Substation near Lethbridge, Alberta. Thirty yr of climate data from Fort Keogh and 50 yr of climate and forage data from Manyberries were used to develop regression equations predicting annual forage production. The results suggest that April, May, and June precipitation reasonably predict forage production. Equations developed from simulated data did not find July precipitation to be significant. Although when utilizing the actual forage production data from Lethbridge July precipitation was a significant
predictor, adding July precipitation did not increase the ability of the equation to detect emerging drought. These results indicate that forage production can reasonably be forecasted by July 1st. Two bio-economic models were parameterized to represent a range-based cow-calf production system in the Northern Great Plains. Treatments were factorially arranged where management, intensity of drought, purchased hay cost, and forage quality were evaluated for effects on system performance. The normal management (NM) scenario included no `early' management changes to emerging drought. Cows were fed hay and/or purchased supplement to maintain performance, herd size, and average weaning weight. The early management (EM) scenario employed weaning calves at an average 90d of age. Treatments were evaluated based on feed costs, average calf weaning weight, ranch gross margin (gross margin - variable costs), and cumulative gross margin (ranch gross margin + net revenue from drylot calves). For
all levels of drought, hay price, and forage quality EM had lower purchased feed costs and higher cumulative gross margins than NM. Most of the variation seen in gross margins between NM and EM strategies was reflected in higher feed costs for the NM scenario. Directly feeding early-weaned calves proved more efficient than feeding cows to produce milk to maintain calf performance.
Impacts
Many cow-calf producers are forced to consider altering management to compensate for the economic hardships due to drought. For producers in the Northern Great Plains, early detection of drought and early changes in management, which include early weaning and drylot feeding calves, can forestall the negative economic impacts of drought over that of merely supplementing cow-calf pairs.
Publications
- Tess, M. W. 2002. Using genetic tools to meet market targets without sacrificing maternal performance. J. Anim. Sci. 80:(E. Suppl. 1)E94-E103. Available at: http://www.asas.org/symposia/vol80/jas1712.pdf.
- Julien, D. J. and M. W. Tess. 2002. Effects of calving date, weaning date, and duration of fall grazing on profitability in range beef cattle enterprises. J. Anim. Sci. 80:1462-1469.
- Tess, M. W., and K. C. Davis. 2002. Gordon Dickerson: Defining economic efficiency of beef production. Proc. Beef Improv. Fed. Conf. available at: http://www.beefimprovement.org/proceedings/tess.html
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Progress 01/01/01 to 12/31/01
Outputs
Computer simulation was used to evaluate alternate calving seasons with different calf marketing strategies for their effects on profitability. The simulated ranch mimicked a cow-calf enterprise under range conditions representative of the Northern Great Plains and utilized Hereford/Angus rotational breeding systems. Calving seasons studied were spring (SP, beginning March 15), summer (SU, May 15), and fall (FA, August 15). Weaning dates were October 31, December 15, and February 1 for SP, SU, and FA. Herd size for fixed forage resource was 510, 518, and 610 cows for SP, SU, and FA. Marketing strategies included: 1) sale at weaning, 2) sale after backgrounding in a custom lot, 3) sale after backgrounding and finished in a custom lot, 4) sale after fed and finished in custom lot, 5) sale September 31 after placed in drylot and summer grazing, 6) sale after drylot, summer grazing, and finishing in a custom lot. Input prices representing peak, descending, valley, and
ascending price periods were developed from 1990's cattle cycle where quarterly cattle prices were adjusted for inflation (1996 basis). Profit was measured as ranch gross margin (RGM, gross ranch returns minus variable costs). Cumulative gross margin (CGM, RGM plus profit or loss from retained ownership) was used to compare alternate marketing scenarios. Varying degrees of profit were recorded for all calving seasons when cattle were retained through various retained ownership options and evaluated at different stages of the cattle cycle. Peak prices increased CGM for all calving seasons, SP ranked first, throughout. Retained ownership was not profitable for SP and SU during descending prices, although FA benefited from retained ownership strategies. Valley prices significantly increased FA CGM when retained ownership options were utilized. Under ascending prices SP and SU increased CGM only with Option 5, FA increased CGM in Options 4, 5, and 6. Cattle must be retained through
slaughter for FA to be competitive. Analyses do not suggest switching from SP to SU or FA. Retained ownership strategies used throughout cattle cycle resulted in varied profit/loss among systems. System rankings reflect differences in herd size, cow feed costs, calf weaning weight, and seasonal market prices.
Impacts
Increasing production costs, seasonal fluctuations in cattle prices, and various retained ownership opportunities provide incentives for beef producers to consider changing calving seasons as a means to improve profit. Our studies suggest that for enterprises managing forage resources similar to those in the Northern Great Plains, optimal marketing strategies for calves are not constant throughout the cattle cycle and different for different calving seasons.
Publications
- Shanks, B. C., Tess, M. W., Kress, D. D., and Cunningham, B. E. 2001. Genetic evaluation of carcass traits in Simmental-sired cattle. J. Anim. Sci. 79:595-604.
- Julien, D. J. and M. W. Tess. 2002. Effects of calving date, weaning date, and duration of fall grazing on profitability in range beef cattle enterprises. J. Anim. Sci. (Accepted for publication).
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Progress 01/01/00 to 12/31/00
Outputs
Our objectives were to estimate genetic parameters for carcass traits and evaluate the influence of slaughter end-point on estimated breeding values (BV). Data provided by the American Simmental Association were divided into three sets: 1) 9,604 records of hot carcass weight (CW) and percent retail cuts (PRC), 2) 6,429 records of CW, PRC, and marbling score (MS), and 3) 1,780 records of CW, PRC, MS, fat thickness (FT), and ribeye area (REA). Weaning weights (WW) from animals with carcass data plus data from their weaning contemporaries were used. Data were analyzed with a multiple-trait animal model and REML procedures to estimate genetic parameters and BV at an age-, CW-, MS-, or FT-constant basis. The model for carcass traits included fixed contemporary group and covariates for breed, heterozygosity, and slaughter end-point, plus random additive direct genetic and residual effects. Weaning weight was preadjusted for founder effects, direct and maternal heterosis,
age of dam, and age of calf. The model for WW included fixed contemporary group and random additive direct genetic, maternal genetic, maternal permanent environment, and residual effects. Heritabilities from data set 1 were 0.34 for CW and 0.25 for PRC on an age-constant basis, and 0.25 for PRC on a CW end-point. Heritabilities for data set 2 were 0.35, 0.24, and 0.36 for CW, PRC, and MS, respectively, at an age-constant basis. Data set 2 heritabilities were 0.25 for PRC and 0.34 for MS at a CW-constant basis, and 0.33 for CW and 0.25 for PRC at a constant MS end-point. Age-constant heritabilities for data set 3 were: CW, 0.32; PRC, 0.09; MS, 0.12; FT, 0.10; and REA, 0.26. Heritability estimates for data set 3 at a CW-, MS-, and FT-constant basis were similar to those at an age-constant basis. Heritabilities were 0.12 for PRC, 0.12 for MS, 0.14 for FT, and 0.22 for REA at a CW-constant basis; 0.30 for CW, 0.09 for PRC, 0.10 for FT, and 0.28 for REA at a constant MS end-point; and
0.33, 0.17, 0.13, and 0.29 for CW, PRC, MS, REA at a FT-constant basis. Genetic correlations among traits varied across groups and end-points, but suggested it should be possible to select for improved lean yield without sacrificing quality grade. Correlations were calculated among BV computed at different end-points. Adjustment to various end-points resulted in some changes in BV and re-ranking of sires, especially for PRC; however, number of records available had a larger influence than slaughter end-point.
Impacts
National genetic evaluation of carcass traits should accurately rank animals within the production systems in which their progeny will perform. This research identifies areas in current methodologies that may require modification.
Publications
- Tess, M.W. 1999. Genetic aspects of replacement heifers in current and future production systems. Proc. Am. Soc. Anim. Sci. Available at: http://www.asas.org/jas/symposia/proceedings/0901pdf.
- Tess, M.W. and Kolstad, B.W. 2000. Simulation of cow-calf production systems in a range environment. I. Model development. J. Anim. Sci. 78:1159.
- Tess, M.W. and Kolstad, B.W. 2000. Simulation of cow-calf production systems in a range environment. I. Model evaluation. J. Anim. Sci. 78:1170.
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Progress 01/01/99 to 12/31/99
Outputs
A mathematical computer model of beef cattle production systems was developed to simulate the dynamic relationships among cattle genotype, physiological state, forage quality, and management in range environments. Forage intake, energy and protein metabolism, growth, reproduction, lactation, and changes in chemical body composition are simulated for individual animals over complete life cycles. Expenses driven by animal performance, management decisions, and land resources are tabulated. Several biological and economic measures of system performance may be computed, including ratios of inputs (e.g., DM, CP, ME, $) to outputs (e.g., wt, lean), breakeven prices, and annual gross margin per cow or ranch. Four experiments were conducted to demonstrate: 1) life-cycle weight and body condition changes for different genotypes raised in a northern range environment, 2) responses in forage intake and weight to changes in forage quality, protein supplementation, and cow
physiological state, 3) responses in reproduction, weight, body condition, and calf growth to differences in pre- and postpartum nutrition, and 4) differences in enterprise efficiency and profit for different genotypes and mating systems. Results indicated that the model performs acceptably for the types of situations for which it was designed, and highlighted areas of animal science where more information is needed in order to better understand and manipulate beef cattle systems.
Impacts
The model should be a useful tool to address several breeding and management questions relevant to cow-calf production systems in the Northern Great Plains and Rocky Mountain West. There are several enterprise level problems in livestock production that can only be studied through simulation, because they are either too expensive or time consuming to address through traditional experiments.
Publications
- Almahdy, H., M. W. Tess, E. El-Tawil, E. Shehata and H. Mansour. 2000. Evaluation of Egyptian sheep production systems. I. Breed crosses and management systems. J. Anim. Sci. 78:283.
- Almahdy, H., M. W. Tess, E. El-Tawil, E. Shehata and H. Mansour. 2000. Evaluation of Egyptian sheep production systems. II. Breeding objectives for purebred and composite breeds. J. Anim. Sci. 78:288.
- Tess, M. W. and B. W. Kolstad. 2000. Simulation of cow-calf production systems in a range environment. I. Model development. J. Anim. Sci. (accepted).
- Tess, M. W. and B. W. Kolstad. 2000. Simulation of cow-calf production systems in a range environment. I. Model evaluation. J. Anim. Sci. (accepted).
- Tess, M. W. 2000. Genetic aspects of replacement heifers in current and future production systems. J. Anim. Sci. (accepted).
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Progress 01/01/98 to 12/31/98
Outputs
Our objective was to evaluate life-cycle performance of flocks of two Egyptian breeds, Rahmani (R) and Ossimi (O), and their crosses with Finnish Landrace (F) in two management systems. Management systems were one mating season per year (1M) and three mating seasons per two years (3M). Breeds and crosses studied included purebred R and O, F1 crosses 1/2F-1/2R (FR) and 1/2F-1/2O (FO), and inter-se matings of 1/4 F-3/4 R (RFR) and 1/4 F-3/4 O (OFO) . A dynamic computer model was used to simulate animal performance and enterprise efficiency and profit. Two measures of biological efficiency were computed: kg TDN input per kg empty body weight output (TDN/EBW), and kg TDN input per kg carcass lean output (TDN/CLN). Profit was measured as gross margin (income minus variable costs per ewe per year, GM/EWE). Input parameters for the model were obtained from published results and analyses of data collected from experimental flocks of the same genetic stocks in Egypt. Profit
for FR and RFR was 42 and 6% higher in 1M compared to 3M. However, profit for all other genetic types 4 to 8% greater in 3M than 1M. Breed rankings changed depending on the measure of evaluation (i.e., biological efficiency or profit). Maximization of system output did not necessarily improve efficiency. Under accelerated lambing systems greater overhead costs associated with labor, nutrition and specialized facilities offset gains in ewe productivity. Genetic stocks should be matched to resources and management systems.
Impacts
(N/A)
Publications
- Tess, M.W. and Fuller, W.L. 1998. Elk impacts on beef enterprise profitability. J. Anim. Sci. 76(Suppl. 1):281.
- Fuller, W.L. and Tess, M.W. 1998. Economic impacts of elk on Southwestern Montana beef enterprises. Proc. Montana Nutr. Conf. pp 14-17.
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Progress 01/01/97 to 12/31/97
Outputs
Using computer simulation we studied the effects of management changes in calving date, weaning date, and grazing season length on production system performance. Production systems in northern plains and mountain valley enviroments were simulated. Data to parameterize aproduction systems were obtained from ranches in 4 counties. Ranches in SE Montana (northern plains) tended to calve later in the spring, use British crossbred cows, and wean smaller calves than ranches in central Montana (mountain valleys). We simulated changes in grazing season length, start of breeding season, and weaning date in a factorial desing. Profitability was measured as ranch gross margin, with available ranch-raised forage resources constrained to fixed levels. Extending the grazing season later into the fall and(or)increasing calf age at weaning by weaning later increased profit for northern plains ranches where calving occurs later in the spring (mean date for start of breeding = June 9)
and late gestation nutritional requirements were not neglected. In mountain valley environments, where calving occurs earlier in the spring (mean date for start of breeding = May 6), extending the grazing season led to excessive nutritional stress, longer calving intervals, lower reproductive rates, and lower profits. Production systems that allow a greater proportion of feed resources to be supplied by grazed forages tend to be more profitable, even with fewer cows, as long as reproductive performance is not reduced.
Impacts
(N/A)
Publications
- JULIEN, DEBRA J., 1997. The effects of calving date, weaning date, and duration of fall grazing on the sustainability of beef cow-calf operations in Central and Southeastern Montana. M.S. Thesis. Montana
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Progress 01/01/96 to 12/30/96
Outputs
Data from 11 ranches were used to parameterize a bioeconomic computer model of cow/calf production. Effects of changes in breeding date (BD), weaning date (WD), and range removal date (RR) on gross margin (GM = gross income - variable costs) for a ranch with a fixed forage resource base (3000 AUM range and 640t hay) were simulated. Breeding season was 66 days with BD starting on day 132, 146, 160, 174, or 188. Calf sales and WD were simultaneous on day 279, 293, 307, 321, or 335. Range removal occurred on day 279, 293, 307, 321, or 335 and cows were fed stored forages thereafter. Five replications were simulated for combinations of BD, WD, and RR in a factorial design. Data were analyzed using least squares procedures. Herd size decreased with later RR. Interactions for BD x WD and BD x RR were significant for both GM and BE. The GM increased with earlier BD and later WD. When WD=279, GM was $16,996 higher for BD=132 than for BD=188, but only $10,474 higher for
WD=335. When BD=132, GM increased $1,911 by changing WD from 279 to 335, compared to $8,433 when BD=188. The GM increased with earlier BD and later RR. For RR=279, GM was $14,972 higher for BD=132 than for BD=188, but only $10,599 higher when RR=335. Moving RR=279 to 335 increased GM $6,915 when BD=132, but $11,287 when BD=188. Results suggest that GM is improved by increasing calf weaning age and extending the grazing season, even if herd size must be reduced.
Impacts
(N/A)
Publications
- Snelling, W. M., M. D. MacNeil, D. D. Kress, D. C. Anderson, and M. W. Tess. 1996. Factors influencing genetic evaluations of linebred Hereford cattle in diverse environments. J. Anim. Sci. 74:1499.
- Kress, D. D., K. C. Davis, and M. W. Tess. 1996. Adjusting scrotal circumferenceof yearling beef bullls in five composites. Can. J. Anim. Sci. 76:189.
- Brownson, R. M., B. D. Nisley, L. C. Gagnon, M. W. Tess, R. B. Staigmiller, C. B. Campbell, and D. L. Step. 1996. Pre-weaning responses of estradiol benzoate and zeranol of steers and heifers (Phase 1). Proc. WSASAS 47:89.
- Julien, D. J. and M. W. Tess. 1996. Simulated effects of changes in breeding dates, weaning dates, and grazing season length on production efficiency and gross margin for southeastern Montana cow/calf operations. Proc. WSASAS 47:244. Abrsta
- Boss, D. L., T. S. Hirsch, D. D. Kress, D. E. Doornbos, D. C. Anderson, M. W. Tess, R. P. Ansotegui, J. E. Sprinkle, K. C. Davis, B. E. Olson, and E. J. Swenson. 1996. Forage intake of Hereford and Tarentaise beef cattle on native range. J.
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Progress 01/01/95 to 12/30/95
Outputs
We continue to refine our model of beef cattle production. A paper describing the model has been written and submitted for publication. We are using the model to evaluate the net effects of genetic reductions in empty body fat deposition on life-cycle productivity and herd profitability. This project attempts to quantify some of the trade-offs that may accompany selection for decreased subcutaneous fat. Several possible physiological mechanisms (selection responses) by which greater carcass leanness might be achieved in the beef industry (see objectives) are being studied for their effects on cow-calf production efficiency. We hope to be able to quantify the economic incentives required to merit selection for decreased fat deposition, and to identify those potential genetic responses that are least costly to cow-calf producers. The system of inference will be an eastern Montana range cow-calf production unit. Key system response variables include profit/cow/yr,
profit/ranch/yr, annual cow cost, $/kg steer equivalent wt., calf wt weaned/cow exposed, and calves weaned/cow exposed.
Impacts
(N/A)
Publications
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Progress 01/01/94 to 12/30/94
Outputs
We continue to refine our model of beef cattle production. A paper describing the model has been written and will be submitted for publication soon. We are currently using the model to study the effects of management changes in calving date, weaning date, and grazing season length on production system performance. The rational behind this work is related to the high cost of winter feeding in northern range production systems. Winter feed costs associated with stored or purchased feeds can be reduced by a) delaying calving time and(or) b) extending the grazing season while simultaneously reducing stocking rate. To offset weaning weight decreases due to younger calf age, later weaning times will also be studied. Net effects of these practices will be dependent on interactions between body condition, nutrient partitioning, range forage quaity, supplementation, and input prices.
Impacts
(N/A)
Publications
- TESS, M.W., AND M.D. MACNEIL. 1994. Evaluation of cytoplasmic genetic effects in Miles City Line 1 Hereford cattle. J. Anim. Sci. 72:851.
- DAVIS, K.C., M.W. TESS, D.D. KRESS, D.E. DOORNBOS, AND D.C. ANDERSON. 1994. Life cycle evaluatin of five biological types of beef cattle in a cow-calf range production system. I. Model Development. J. Anim. Sci. 72:2585.
- DAVIS, K.C., M.W. TESS, D.D. KRESS, D.E. DOORNBOS, AND D.C. ANDERSON. 1994. Life cycle evaluation of five biological types of beef cattle in a cow-ccalf range production system. II. Biological and economic performance. J. Anim. Sci. 72:2591.
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Progress 01/01/93 to 12/30/93
Outputs
A computer simulationmodel was used to evaluate economic performance in five strains of composite cattle developed and marketed by a private breeder, Beefbooster Cattle Alberta Ltd. There were three maternal strains (M1, M2, and M4), and easy-calving sire strain (M3), and a terminal cross strain (Tx). The production system simulated was a northern range cow-calf operation. All strains were evaluated in purebred systems and in specialized crossbreeding systems. Three rotational crossbreeding systems were simulated: three-way rotation using maternal strains (ROT), ROT used with an easy calving sire (M3) on yearling replacement heifers (ROT3), and ROT 3 used with Tx bred to mature cows (ROT3X). Economic effects of changing genetic potential of individual traits within each of the strains using ROT3X were also measured. Traits examined were mature weight, weaning weight, birth weight, probability of conception, age at first estrus (puberty), and milk production. Maternal
strains had similar estimatedd profits followed by Tx and M3. All three crossbreeding systems were more profitable than any purebred system. Changes in mature weight, weaning weight and, probability of concception were shown to be important for all maternal strains. Changes in milk production and age at first estrus did not prove to be very important in thses strains at current levels of performance. Weaning weight and birth weight were both important in M3 while only weaning weight was important in Tx.
Impacts
(N/A)
Publications
- LAMB, M.A., M.W. TESS, AND O.W. ROBISON. 1993. Evaluation of mating systems involving five breeds for integrated beef productino systems. IV. Accounting forvariability and genetic trends. J. Anim. Sci. 71:587. 1993.
- COOK, B.R., M.W. TESS, AND D.D. KRESS. 1993. Effects of selection strategies using heifer pelvic area and sire birth weight expected progeny differences on dystocia in first-calf heifers. J. Anim. Sci. 71:602. 1993.
- TESS, M.W., M.A. LAMB, AND O.W. ROBISON. 1993. Comparison of breeds and matingsystems for economic efficiency in cow-calf production. Montana AgResearch 10:22. 1993.
- TESS, M.W., M.A. LAMB, AND O.W. ROBISON. 1993. Comparison of breeds and mating systems in integrated beef production systems. Montana AgResearch 10:25. 1993.
- DAVIS, K.C., M.W. TESS, D.D. KRESS, AND D.E. DOORNBOS. 1993. Heterosis for economic traits for different biologiccal types of beef cattle. J. Anim. Sci. 71 (Suppl. 1):104. 1993.
- TESS, M.W., AND B.W. KOLSTAD. 1993. Simulation of cattle production in a range environment: I) Development of a model. J. Anim. Sci. 71 (Suppl. 1):105. 1993.
- KOLSTAD, B.W., AND M.W. TESS. 1993. Simulation of cattle production in a range environment: II) Comparison of maternal and paternal strains and mating systems.J. Anim. Sci. 71(Suppl. 1):105. 1993.
- KOLSTAD, B.W. 1993. Economic values of performance traits in maternal and pater.
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Progress 01/01/92 to 12/30/92
Outputs
Computer simulation was used to evaluate the effects of selection strategies based on heifer pelvic area and sire birth weight EPD on dystocia in first-calf heifers.Selection within unrelated sets of yearling heifers was based on breeding the top 40,60,80 or 100% of available heifers as determined by yearling pelvic area (YRLGPA).Bulls were selected based on EPDs for birth weight (SEPD;-2.7,-1.8,-.9,0,.9, 1.8 kg.).Calving difficulty score (1,2,3,4), and incidence of dystocia (0,1) were predicted from the ratio of precalving pelvic area to calf birth weight.Effects of SEPD were significant (P<.05) for birth weight,calving difficulty score and dystocia frequency.Differences among levels of heifer selection for YRLGPA were significant for YRLGPA,precalving pelvic area,birth weight,and calving difficulty score but not for the frequency of dystocia.A 1kg decrease in SEPD decreased calving difficulty score by .12 units and decreased the frequency of dystocia by 4%;whereas
each 10% increase in selection pressure on YRLGPA reduced calving difficulty score by only .02 units and had no detectable effect on dystocia frequency.Therefore, selection of sires with low birth weitht EPD will be much more effective than selection of replacement heifers based on yearling pelvic area in reducing both the incidence and severity of dystocia in first-calf beef heifers.
Impacts
(N/A)
Publications
- TESS,M.W. AND F.A.THRIFT. 1992. Genetic Aspects of Beef Cattle Production in the Southern Region.Southern Cooperative Series Bulletin 367.
- THRIFT,F.A.,M.W.TESS AND C.J.BROWN. 1992. Selection II.National cattle evaluation.In:Genetic Aspects of Beef Cattle Production in the Southern Region.Southern Cooperative Series Bulletin 367,pp 55-59.
- TESS,M.W. AND M.A.LAMB. 1992. Crossbreeding I.Concepts and Systems.In:Genetic Aspects of Beef Cattle Production in the Southern Region.Southern Cooperative Series Bulletin 367,pp 61-68.
- TESS,M.W. 1992. Biotechnology and Beef Cattle Breeding.In:Genetic Aspects of Beef Cattle Production in the Southern Region.Southern Cooperative Series Bulletin 367,pp. 85-94.
- BOIK,R.J.,M.W.TESS AND C.TODD. 1993. Technical note on computing tests of fixed effects in a restricted class of mixed models.J.Anim.Sci.71:51.
- LAMB,M.A.,M.W.TESS AND O.W.ROBISON. 1992. Evaluation of mating systems involving five breeds for integrated beef productions systems.IV.Accounting for variability and genetic trends.J.Anim.Sci.(accepted).
- COOK,B.R.,TESS M.W. AND D.D.KRESS. 1992. Effects of selection strategies using heifer pelvic area and sire birth weight expected progeny differences on dystocia in first-calf heifers.J.Anim.Sci.(accepted).
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Progress 01/01/91 to 12/30/91
Outputs
Computer models were used in simulating integrated cow-calf-feedlot production systems. Angus (S). Charolais (C), Hereford (H), Limousin (L), and Simmental (S) purebreds and two-and three-breed rotational crossbreds were included. Models were deterministic and based on data reported primarily from the 1970's. Variation in carcass weights were determined to predict distributions of carcass weights and values around a 272 to 318 kg target range. Also, data were updated to 1984 base by increasing birth, weaning, yearling and mature weights to account for genetic trends with breeds. Two slaughter endpoints were considered: 288 kg carcass weight and low choice. Accounting for variation around the target increased estimated efficiency A and AH crosses at low choice (input costs/carcass value), while rankings among other breed combinations were relatively unchanged. Including genetic trends resulted in increased efficiencies among breed combinations with previously
underweight carcasses at low choice (A and AH), measured either as input costs/carcass weight or lean weight values. Therefore, accounting for genetic improvements and variation within breeds included in simulations reranked breed combinations when evaluated as a percent fat slaughter endpoint.
Impacts
(N/A)
Publications
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Progress 01/01/90 to 12/30/90
Outputs
Angus (A), Charolais (C), Hereford (H), Limousin (L) and Simmental (S) breeds were included in computer models simulating an integrated cow-calf-feedlot production system. Three mating systems were used: purebred (PB), and two- (2R) and three-breed (3R) rotational crossbreds. Breed information was taken from the literature. Calves produced in the cow-calf segment were fed out in a feedlot to four carcass endpoints: 440-d,457-d,288kg weight, and low choice. Cull cows were slaughtered after weaning. Economic efficiencies improved with cross breeding; however, breed type rankings depended on how efficiencies were measured. Two-breed rotations were 11 to 28% and 3R 12-27% more efficient than PB systems. Charolais and(or) H x A or L ranked most biologically efficient at all endpoints. Angus and(or) H x C or S crosses ranked highest for input costs/kg carcass weight, while C and(or) L x A or H crosses ranked highest for input costs/kg lean weight. For input costs/carcass
weight value, A and(or) H crosses ranked highest at age and fat endpoints, while A and C crosses ranked highest at weight endpoint. For input costs/lean weight value, A,H and(or) L crosses ranked higher at age endpoints, C and L crosses ranked highest at weight endpoint and A and(or) H x C or S ranked highest at fat endpoint. Therefore, choosing breed combinations for integrated systems depends on finishing and marketing endpoints.
Impacts
(N/A)
Publications
- LAMB, M.A., O.W. ROBISON AND M.W. TESS. 1990. Genetic parameters for carcass traits in Hereford bulls. J. Anim. Sci. 68:64-69.
- TESS, M.W. AND O.W. ROBISON. 1990. Evaluation of cytoplasmic genetic effects in beef cattle using an animal model. J. Anim. Sci. 68:1899-1909.
- TESS, M.W. AND R.C. GREET. 1990. Considerations for the specification & statistical estimation of differences among animals in the partial efficiencies of feed energy utilization. J. Dairy Sci. 73:3297-3305.
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Progress 01/01/89 to 12/30/89
Outputs
Work was initiated on objective 1. Based on results from the literature conceptual models of cattle growth, development and reproduction have been synthesized. Currently, these models are being refined, linked together and translated into computer code. Emphasis is being placed on the inter-relationships among ad libitum forage intake, body composition and reproductive status. The most rapid way for cattle producers to respond to changes in market demand for cattle type may be through substitution of breed resources and application of specific mating systems. A computer model is being constructed to simulate a variety of crossbreeding systems and specific breed combinations. Weighted least-squares estimates of breed effects and heterosis (including specific heterosis) were computed using least-squares means from literature reports. Cattle performance and corresponding economic inputs will be predicted from birth through slaughter. Specific combinations of breeds and
crossbreeding systems will be compared for input/output production system economic efficiency. Carcass outputs will be valued according to potential future indexes of carcass merit. Systems will be compared when slaughter is scheduled for constant weight, constant age or constant carcass composition endpoints.
Impacts
(N/A)
Publications
- LAMB, M.A. and TESS, M.W. 1989. Evaluation of crossbreeding systems for small beef herds: I. Single-sire systems. J. Anim. Sci. 67:28.
- LAMB, M.A. and TESS, M.W. 1989. Evaluation of crossbreeding systems for small beef herds: II. Two-sire systems. J. Anim. Sci. 67:40.
- LAMB, M.A., ROBISON, O.W. and TESS, M.W. 1989. Genetic parameters for carcass traits in Hereford bulls. J. Anim. Sci. 67:37(Suppl. 1).
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