Percentage of Bull Calves Dairy Industry Sold as Beef
Beef Cattle Economic Selection Indices
Bob Weaber
Kansas Land Academy
bweaber@ksu.edu
*Click here for printable pdf version.
Summary: Option indices provide a single value, commonly reported in dollars, for the selection of breeding stock that optimizes selection on a number of traits the define profit in a particular production scenario. Selection indexes simplify selection by weighting EPDs past appropriate economical values to estimate the net merit of a pick candidate under a predefined breeding objective or goal.
Effective sire option is a daunting procedure for many seedstock and commercial beefiness producers. Indeed, more than one or 2 traits touch profit in beef cattle enterprises. A vast array of EPD makes selection challenging and depending on breeding organisation and marketing methods, traits take dissimilar economic values (contributions to profit) beyond enterprises. Pick index provides a broad methodology for optimally weighting EPD which have economic importance to various defined breeding objectives. Selection indexes, when properly aligned with marketing endpoints, can essentially simplify sire selection decisions by focusing selection on a single metric associated with enterprise profitability. Utilise of choice alphabetize can assistance producers focus option force per unit area on economically relevant traits in a consequent way across years and seedstock vendors. Add-on of genomic data to EPD ciphering systems adds accuracy to the resulting EPD and selection indexes derived from them.
Why do we need indexes?
The complications of multiple-trait selection and animal breeding decisions may be best summarized by Dr. Lanoy North. Hazel in the opening paragraph of his landmark paper on the topic of choice indexes published in the journal Genetics in 1943:
The idea of a yardstick or selection index for measuring the cyberspace merit of breeding animals is probably virtually as old as the art of animal breeding itself. In do several or many traits influence an beast's practical value, although they practice and then in varying degrees. The information regarding different traits may vary widely, some coming from an brute's relatives and some from the animate being'southward own performance for traits which are expressed one time or repeatedly during its lifetime….These factors brand wise pick a complicated and uncertain procedure; in addition fluctuating, vague, and sometimes erroneous ethics often cause the improvement resulting from selection to be much less than could be achieved if these obstacles were overcome.
Hazel points to the complexities of selection of individuals when many traits are observed and when the 'data' or operation record of an individual and its ancestors, collateral relatives and progeny may vary considerably. The overall net merit of the individual, considering several traits of economic importance, provides a superior selection criterion than single trait pick or multiple trait option via independent alternative levels.
Hazel's pioneering work solidified the thought of a breeding objective or goal using a quantitative method. The amass genotype described by Hazel was a linear part (selection index) of observations such that the observations of each trait were weighted past the relative economic value of that trait. The consequence was a unmarried value for each animal that represented an objective valuation of the overall satisfaction with that animate being. In production agriculture, our level of satisfaction with an animal or system is more often than not measured in profit. The selection alphabetize provided a natural connectedness between the net merit of an animal'southward genotype and its relationship with turn a profit.
Every bit beef producers, nosotros know that more than than one trait exhibited by beefiness cattle contribute to profit at the enterprise level. Clearly, a moo-cow-calf producer that sells calves at weaning depends on more simply the average weaning weight of calves for profitability. Unproblematic ranch accounting suggests that reproduction rate, calf survivability, moo-cow maintenance feed costs, length of productive life and others influence the total pay weight of weaned calf produced and the cost required to produce that weight. Likewise, the producer that sells calves at harvest relies on more than simply marbling score or quality grade to pay the bills. Reproductive rate of the cow herd, maintenance costs, longevity, not to mention carcass weight, are all factors affecting profitability. Thus, breeding objectives should include all the traits that are of economical relevance.
Economic Indexes Defined
In its simplest grade, the selection index defines an brute's economic merit as a parent in terms of a mathematical function an fauna'due south EPD are weighted by their respective economic value. Traits that have larger impacts on turn a profit or the product goal have larger economical weights associated with them. The index is simply computed then as a sum of EPDs weighted by the relative economic value equally below:
Ii = b1EPDi1 + b2EPDi2 + … + bnEPDin
where,
Ii = the predicted aggregate economic merit of an brute, i, as a parent,
bj = the predicted relative economic weight of trait j, j = 1…n, where n = the total number of traits
EPDij = the Expected Progeny Difference of beast i for trait j.
How to Use Indexes in Selection:
Generalized Indexes
Recently there's been a flurry of activity by researchers and breed associations to develop a diverseness indexes. A bulk of these indexes are finish-indicate or marketing signal focused. These generalized indexes are applied on a breed-wide basis. Generalized indexes are advisable whenever breeding objectives are consistent beyond large segments of an animate being population. Bio-economic simulations are relatively robust across deviations in input costs or product pricing in that the spread of the index value may non match realizations at the ranch level but the ranking of candidate sires is however right. In beef cattle choice, rank of animals (i.e. selecting the 'best') is generally more important than the values associated with index or EPD.
Current Implementation of Option Index
At present a number of breeds have developed selection indices for use by seedstock and commercial producers. Table one below describes the breed association, index name, market progeny terminate-betoken and breeding organisation type (One thousand=maternal trait, R=replacement female, T=terminal or A=all purposed with terminal calves and replacements retained) and index type (C=customizable or G=generalized).
Which Alphabetize Should I use?
For commercial cattlemen that can succinctly define their market endpoint, the selection of sires within breed is dramatically simplified through the utilise of a selection index. The key to success is the selection of the advisable alphabetize by aligning the market place endpoint of the index with your operations endpoint. Misalignment of index and marketplace endpoint is the nigh often observed error in the use of pick index. For instance using a carcass endpoint selection index (such as $B from Angus, CHB from Hereford, TI from Simmental, MTI from Limousin, CV from Gelbvieh, TSPI from Charolais) for replacement female choice or for choice of sires of replacement females is strongly discouraged . These terminal indexes put cypher (0) economic weight on maternal traits which should be the focus of selection for a replacement female. Use of concluding indexes to select sires of replacement females will result in selection for last traits. Ultimately, using a terminal selection alphabetize to produce replacement heifers will produce larger mature weight cows that are likely leaner in body composition.
For many producers that retain heifers from the convenance program and sell either feed cattle or retain ownership through the feed, employ of an all-purpose or replacement heifer index is advised. These indexes provide significant weighting on maternal traits such equally stayability, heifer pregnancy, maternal calving ease, and milk which can dramatically influence to productivity of daughters retained in the herd.
Selection Efficiency
Pick index provides a more efficient option strategy than other forms of selection. Tandem or sequential pick is sometimes used in the beef industry. Tandem selection is the process past which a breeder places pressure on one trait at a time and when choice attains a desired level of performance in the first trait pick pressure is applied to the second trait and so on. This process can be slow and imprecise. Economic gains are dependent on knowing which trait to select for start in the order, what level of a trait maximizes profit and what the economical value is for each trait.
Selection index is too more effective for multiple trait selection than the employ of independent culling levels (ICL). ICL is the process where minimum or maximum thresholds are established for each trait under choice. Animals that achieve all the thresholds are selected. The risk of ICL is that it omits animals that possibly of high value in amass, but just miss one of the threshold values. Selection alphabetize applies weightings to all traits of economic relevance to the goal or endpoint and ranks animals on the aggregate merit so no animal of significant value is omitted from the choice candidate roster.
Impact of Genomically Enhanced EPD on Selection Indices
The principal touch of genomically enhanced EPD (GE-EPD) on selection index is through increased accurateness of prediction for EPDs on which the various selection indices are based. Improvement in accuracy of EPD yield more than reliable selection indices. The incorporation of genomic (DNA marking) information into national cattle evaluation systems has the opportunity to increase the accuracy of young sire selection candidates. Reduction of hazard through improved EPD accuracy of these young candidates adds substantial value to EPDs and resulting selection indices for use by both seedstock and commercial breeders making selection decisions.
| Breed | Index Name | Progeny Endpoint | Breeding Organisation | Index Type |
|---|---|---|---|---|
| Angus | $Westward (Weaning) | weaned feeder calves | A | Yard |
| Angus | $F (Feedlot) | alive fed cattle | T | G |
| Angus | $One thousand (Grid) | beef carcasses sold on grid | T | G |
| Angus | $B (Beef) | beef carcasses from retained buying sold on grid | T | G |
| Charolais | TSPI (Terminal Sire Profitability Alphabetize) | beef carcass sold on grid | T | C |
| Gelbvieh | $Cow | replacement heifers | Thou | One thousand |
| Gelbvieh | CV (Carcass Value) | beef carcass sold on grid | T | G |
| Gelbvieh | FM (Feedlot Merit) | live fed cattle | T | G |
| Hereford | BMI$ (Baldy Maternal Alphabetize) | beef carcass sold on grid; replacement heifers retained | A | G |
| Hereford | BII$ (Brahman Influence Index) | beef carcass sold on filigree; replacement heifers retained | A | G |
| Hereford | CHB$ (Certified Hereford Beefiness Index) | beef carcass sold on CHB grid | T | G |
| Hereford | CEZ$ (Calving Ease Index) | matings to replacement heifers | M | G |
| Limousin | MTI (Mainstream Final Alphabetize) | beef carcasses sold on grid | T | G |
| Ruby Angus | HerdBuilder | beef carcass sold on grid; replacement heifers retained | A | G |
| Red Angus | GridMaster | beef carcasses sold on grid | T | Thou |
| Simmental | API (All Purpose Alphabetize) | beef carcasses sold on grid; replacements retained | A | Thou |
| Simmental | TI (Terminal Index) | beef carcasses sold on grid | T | G |
| * Convenance system: Chiliad = maternal trait, R = replacement female, T = terminal or A = all purposed with last calves and replacements retained; Index type: C = customizable or Yard = generalized | ||||
*Click here for printable pdf version.
Source: https://beef-cattle.extension.org/beef-cattle-economic-selection-indices/
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