Basic Explanation of Epds in Cattle Beef and Swine

Expected progeny differences (EPDs) take been applied to improve the genetics of beef cattle for well-nigh iv decades. Expected progeny differences are predictions of the genetic transmitting power of a parent to its offspring and are used to make selection decisions for traits desired in the herd. For a given trait, EPD values are calculated based on data submitted by producers to brood associations from an beast'due south actual performance, performance of progeny, performance of other relatives, and genomic data (Dna assay, if available).

When Dna information is available, EPD accuracy is improved, and these calculations are referred to equally a Genomic-enhanced EPD (GE-EPD). Thus, in addition to pedigree, operation and progeny data, GE-EPDs utilize genomic test for increased reliability of an animal's EPD (Eenennaam and Drake, 2012; Rolf et al., 2014).

Source: American Angus Association

Combined with all available sources of information, GE-EPDs are the all-time estimate of an animal's genetic value as a parent. Genomics permit better accuracies for younger animals and allows a clear motion picture of genetic traits of involvement, especially those that are expensive to measure such every bit feed efficiency, carcass traits in convenance stock, reproductive traits or maternal traits in bulls.

When a producer buys a immature bull that has GE-EPDs, he is buying with the aforementioned level of conviction in that animal as one that has already sired betwixt 10 and 36 calves, depending on the trait. In this way, GE-EPDs increment accuracy in those animals much earlier in their lives. With all these benefits, continue in heed that genomically-enhancing the EPDs does not change how the EPD tin can be used, it but increases its accuracy.

Tabular array ane. Progeny Equivalents (PE) – Carcass trait PE equate to actual carcass harvest information, not ultrasound browse equivalents.

Trait	PE
Calving Ease Direct	26
Birth Weight	23
Weaning Weight	27
Yearling Weight	23
Dry Matter Intake	12
Yearling Height	17
Scrotal Circumference	15
Docility	12
Claw Angle	10
Foot Angle	10
Heifer Pregnancy	17
Calving Ease Maternal	20
Milk	36
Mature Weight	15
Mature Height	9
Carcass Weight	15
Carcass Marbling	11
Carcass Ribeye	17
Carcass Fatty	14

Source: American Angus Clan (www.angus.org).

EPD Accurateness

Accuracy (ACC) reflects the precision of a prediction for a given animal's EPD and provides u.s.a. with a level of confidence for that creature'southward genetic merit. Bulls with greater accuracy values may be called "proven sires."

The EPD prediction of genetic merit for a trait is the best indicator of expected performance of future progeny, which is expressed as departure from the population's base value. Recognizing that base values may exist unlike amid breeds is important; some breeds employ an average within a specific year, whereas other breeds apply a nonspecific historical bespeak.

To improve the accurateness of EPDs for younger bulls, producers may collect and submit Deoxyribonucleic acid samples, which, depending on the trait, may equates to near 10 progeny records for a sire with no other progeny records contributing to his EPDs. Equally more progeny data are obtained for a sire, the relative contribution of genomic data to overall EPD accuracy is reduced.

The lack of confidence associated with EPDs on immature cattle comes from non having progeny or performance data, both of which increase the accurateness of the EPD. In immature bulls, for example, about of their genetic value is based on their pedigree. As these animals age and have offspring, we know more and more than about their genetic merit. This increased conviction is denoted past an increment in the accurateness value (0–1 scale) associated with each EPD. It does non necessarily mean that the EPD increases if accuracy increases. It just means the EPD becomes closer to the true value, whether it increases or decreases. Call back that EPD stands for expected progeny difference. Genotyping a immature animal increases accuracy because SNP genotypes have similar value to evaluating additional progeny.

How to Use EPDs

Before getting started with EPDs, producers should define their specific production goals first and and so select based on the EPDs that will best allow them to meet those production goals. For example, producers selling calves at weaning may prioritize EPDs differently than producers wishing to retain heifers or producers wishing to retain ownership through the feedlot. Therefore, producers should apply EPDs based on the pick of breeding bulls that meet their personal production goals.

Hither are some traits that tin be used by those producers who sell the entire calf crop at weaning or following a backgrounding phase:

• Birth Weight (BW);
• Calving Ease (CE) or Calving Ease Straight (CED);
• Weaning Weight (WW);
• Yearling Weight (YW).

Selecting for these traits adds ease to the beef producers daily workload, past attempting to reduce the number of assisted births, while calculation auction value (with weight) to those calves that volition be sold as feeders.

For producers who retain replacement heifers, the following EPDs are ofttimes used in addition to the previous list:

• Calving Ease Total Maternal (CETM), Calving Ease Maternal (CEM) or Maternal Calving Ease (MCE);
• Milk Product (Milk) or Maternal Milk (MM);
• Full Maternal (TM), Maternal Weaning Weight (MWW) or Maternal Milk and Growth (M&G);
• Mature Weight (MW) or Mature Cow Weight (MCW);
• Maintenance Energy (ME);
• Heifer Pregnancy (HP or HPG);
• Stayability (STAY);
• Mature Height (MH);
• Scrotal Circumference (SC or SCR).

These traits are all related to the predicting the success of replacement heifers at becoming valuable dams in the herd.

Producers who heighten their ain animals through the feedlot will often focus on the traits below, in improver to the maternal traits previously mentioned:

• Carcass Weight (CW) or Hot Carcass Weight (HCW);
• Fat (Fat) or Dorsum Fat (BF);
• Marbling (MB, MRB or MARB)
• Yield Form (YG);
• Shear Force (SHR);
• Rib-Heart Expanse (REA or RE).

In this case, the traits selected are value traits for cattle marketed at the end of life.

Example 1 of Using EPDs for Balderdash Selection

In this example, a producer is looking for a Charolais bull to utilize on black Angus-influenced cows that accept had at least 2 calves. In this example, the producer is using the Charolais in what is chosen a last cross, all calves being sold at weaning or after a backgrounding period for slaughter. The producer wishes to maintain calving ease and have the do good of enhanced weight at the time of sale. Based on the table beneath, which bull would be more appropriate for the stated purpose based on EPD values?

Table 1. Charolais bulls¹ for apply on mature crossbred females.

Balderdash	CE	BW	WW	YW	MCE	MILK	SCR	CW	REA	FAT	MARB
A	11.6	-four	27	58	3.9	23	one.1	20	0.66	0.041	0.18
B	2.9	3	59	99	2.2	1	ii.1	49	0.96	0.041	0.22
Brood Average	three.1	0.seven	24.4	43.viii	4	7.ix	0.half-dozen	14.seven	0.26	0.002	0.04

¹Bulls information retrieved from Select Sires Beef and Genex.

With the focus on this phase of production, accent should be given mainly to 3 traits: CE, BW, and WW. We are assuming that these bulls are most probable immature and have low accuracies, or are non proven.

Calving ease (CE) relates directly to the bull's pressure on nativity weight. Balderdash B is expected, on boilerplate, to have viii.7 percent fewer unassisted births when bred to 2-twelvemonth-old heifers than Bull A (a disadvantage if breeding to heifers). Bull B has an expected birth weight that would be 7 pounds heavier, on boilerplate, than Balderdash A. Thus, while clear that Bull A would exist more advisable for breeding heifers, our producer is interested in breeding multiparous cows. Therefore, because balderdash B has a BW EPD that is simply 2.3 lb. heavier than the brood average, the producer likely will want to put their emphasis on other traits. Examination of the WW EPD indicated that Bull B would be expected to produce calves that are 32 pounds heavier at weaning, on boilerplate, than Balderdash A. This departure is what commonly drives sales and profits at weaning. Thus, if the producer decides to sell calves at weaning fourth dimension, Balderdash B may be the advisable choice. In add-on, while perhaps not equally important if the producer sells at weaning, this producer may also want to look at YW and some carcass traits when selecting their bulls. In this example the logic is that selling high quality calves at weaning that volition perform well effectually yearling historic period and through the feedlot may create a reputation of raising high-value calves that are profitable for feedlot owners. Considering this is a terminal cantankerous, no heifers volition be retained, and maternal traits tin can be ignored.

Option by Index

Now, in addition to individual trait choice using EPDs, animals can also be selected on an "alphabetize". An economic index is a tool used to select for several traits at in one case based on a specific breeding objective. An economical index approach considers genetic and economical values also as the relationships between traits to select for turn a profit. When genetic improvement is desired for several traits that may differ in variability, heritability, economic importance, and in the correlation among their phenotypes and genotypes, simultaneous multiple-trait index selection has been more than constructive than independent culling levels or sequential selection (Philipsson et al., 1994; Garrick and Golden, 2009).

These are some examples of the economic indices offered by breed associations. Each brood clan has many more selection indices and producers are encouraged to investigate these options.

From the American Angus Association (AAA, 2020):

• Beefiness Value ($B), an index value expressed in dollars per head, is the expected boilerplate difference in future progeny performance for postweaning and carcass value.
• Combined Value ($C), expressed in dollars per head, is an alphabetize which includes all traits that brand upward both Maternal Weaned Calf Value ($Thousand) and Beefiness Value ($B) with the objective that commercial producers will supervene upon xx% of their breeding females per yr with replacement heifers retained inside their own herd.

From the American Hereford Association (AHA, 2020):

• Baldy Maternal Alphabetize (BMI$) is an index to maximize profit for commercial moo-cow-dogie producers who use Hereford bulls in rotational crossbreeding programs on Angus-based cows.
• Certified Hereford Beefiness Alphabetize (CHB$) is a terminal sire alphabetize in which Hereford bulls are used on British-cross cows and all offspring are sold as fed cattle on a CHB pricing filigree.

From the American Simmental Association (2020):

• All-Purpose Index (API) is an alphabetize that evaluates sires for utilise on the entire cow herd (bred to Angus first-calf heifers and mature cows), with the portion of their daughters required to maintain herd size retained and the remaining heifers and steers put on feed and sold on grade and yield.
• Concluding Index (TI) is an index that evaluates sires for use on mature Angus cows, with all offspring put on feed and sold on class and yield.

Case two of Using EPDs for Bull Option

A producer is looking for an Angus bull to breed a direct-bred Angus herd. The producer plans to retain buying of the females to utilise in the breeding herd and sell the calves at weaning. Thus, maternal traits of the females will be important.

Tabular array 2. Angus bulls¹ for apply on straight-bred Angus females.

Bull	CED	BW	WW	YW	CW	Marb	RE	Fat	$M	$W	$F	$G	$B
A	xvi	-0.half dozen	68	129	62	1.viii	1.eleven	-0.028	62	79	124	120	244
B	16	-2.5	64	118	32	0.42	0.53	0.046	51	78	69	38	106
Breed Average2	3	1	26	45	22	0.42	0.32	0.008	52	54	82	44	126

¹Bulls information retrieved from Select Sires Beef.
²Breed average retrieved from The American Angus Clan.

To address the producer'south goal as stated, nosotros can look at the Maternal Weaned Calf Value ($1000) because it provides an indication of expected maternal ability and profit based on sale of weaned calves. Balderdash A will produce calves that will profit, on average, $11 more than Balderdash B using the $M. Bull A will exist the improve buy for this scenario where female person retention and weaned dogie value are both of import.

Across-breed EPD Comparisons

Within a breed, EPDs can be directly compared. Bulls of different breeds tin also be compared, just adjustment factors to the EPDs are needed considering an EPD from i breed evaluation is non directly comparable to an EPD from another breed evaluation. Since 1993, the U.S. Meat Fauna Inquiry Centre (USMARC) has produced a tabular array of these adjustment factors and so that the merit of individuals can be compared across breeds.

Example three of Using EPDs for Balderdash Selection

In this example, suppose a producer needs to make a decision between a Simmental bull and a Limousin balderdash to breed his crossbred cow herd. The important traits for him are BW, WW, YW, and Milk.

Table three. DEPs from unlike breeds to use on a commercial crossbred herd.

Balderdash	CE	BW	WW	YW	Milk	Md	YG	CW	REA	Marb
Simmentalone	17.1	-3.9	68	95.7	26.3	7.4	-0.22	28.ii	0.58	0.35
Limousin1	14	i.7	61	ninety	21	8	-0.73	16	i.23	8

ⁱBulls information retrieved from Select Sires Beefiness.

With the in a higher place information, the producer also needs to access the tabular array below:

Table 4. Adjustment Factors to Guess across-brood EPDs.

Breed	Birth Wt. (lb)	Weaning WT. (lb)	Yearling Wt. (lb)	Maternal Milk (lb)	Marbling Scorea	Ribeye Surface area (in2)	Fat Thickness (in)	Carcass Wt. (lb)
Angus	0.0	0.0	0.0	0.0	0.00	0.00	0.000	0.0
Hereford	1.4	-xvi.v	-44.4	-12.5	-0.xxx	0.02	-0.073	-71.one
Red Angus	2.6	-19.four	-31.four	1.v	-0.03	0.25	-0.040	-13.2
Shorthorn	4.v	-34.iv	-46.6	-0.1	-0.07	0.47	-0.032	5.6
South Devon	2.6	-29.9	-55.4	3.one	-0.53	0.64	-0.213	-68.8
Beefmaster	4.0	23.four	one.ane	7.vii
Brahman	ten.3	53.three	xiv.4	16.seven		0.03	-0.166	-35.9
Brangus	3.1	xiv.9	v.three	12.nine
Santa Gertrudis	five.two	xl.4	39.8	xvi.viii	-0.44	0.12	-0.085	-12.iii
Braunvieh	2.two	-21.1	-46.half dozen	4.1	-0.61	1.00	-0.100	-53.4
Charolais	half dozen.6	32.7	23.2	viii.ane	-0.29	0.79	-0.201	five.1
Chiangu	2.8	-21.1	-36.2	two.five	-0.47	0.59	-0.142	-19.three
Gelbvieh	2.ix	-15.5	-27.ane	8.2	-0.37	0.66	-0.066	one.v
Limousin	2.five	-sixteen.9	-53.9	-ii.four	-0.03	0.59	-0.024	-five.ane
Maine-Anjou	2.4	-thirty.iii	-55.2	-7.0	-0.43	0.95	-0.179	-35.i
Salers	0.9	-eleven.two	-48.0	5.6	0.07	1.08	-0.177	-47.6
Simmental	2.eight	-11.6	-xix.two	1.eight	-0.12	0.45	-0.049	-7.5
Tarentaise	2.7	20.2	-12.ane	xv.7

^aMarbling score units: four.00 = s1°0; 5.00 = Sm00
Source: United states of america Meat Animal Research Middle (2020) through Beef Improvement Federation.

With both tables of information, a table for beyond breed comparisons tin be made, similar to Table 5.

Table 5. Example of using across-breed adjustment factors to convert noncomparable within-breed EPDs to comparable across-breed EPDs.

Bull		BW (lb)	WW (lb)	YW (lb)	Milk (lb)
Simmental	EPD1	-3.9	68	95.7	26.3
	AB Adj. Factorstwo	ii.eight	-11.6	nineteen.2	1.viii
	AB-EPD3	-i.1	56.4	76.5	28.one
Limousin	EPDane	ane.7	61	90	21
	AB Adj. Factors2	2.5	-sixteen.9	-53.9	-2.4
	AB-EPDiii	4.ii	44.1	36.ane	18.6

¹EPDs are the within-breed EPD values from the brood's genetic evaluation for the bull of involvement.
²AB adj. factors are the beyond-breed adjustment factors from Tabular array 1.
^threeBeyond-breed EPDs after adjustment factors are applied to within-breed EPDs.

The beyond-breed (AB) aligning factors for BW are 2.eight lb for Simmental sires and 2.5 lb for Limousin sires. The AB-EPD for that trait is -three.9 lb + ii.viii lb = -one.1 lb for the Simmental bull and 1.seven lb + 2.5 lb = four.ii lb for the Limousin bull. The expected birth weight difference of offspring when both are mated to cows of another breed (due east.g., Angus) would be -1.i lb - four.ii lb = -5.3 lb. At weaning, the Simmental bull will produce heavier calves. This weight difference becomes more evident at yearling age, when the expected yearling weight of the Simmental bull offspring will surpass the Limousin bull offspring by virtually 40 lb. On tiptop of that, its daughters volition produce, on boilerplate, ix.6 lb more milk than the daughters of the Limousin bull. Therefore, the Simmental bull will be easier on heifers (lower nativity weight), provide faster growth pre- and mail service-weaning, and accept daughters that produce more milk.

Benefits of genomic testing females

Selecting females for replacement is ane of the almost challenging aspects of commercial cow-calf production. Besides, heifer development is an expensive suggestion. Therefore, producers may decide whether a given heifer can be productive and profitable before she has had an opportunity to express productivity associated with profitability, including fertility, calving ease, milking ability, growth and mature size. By using a practiced breeding strategy and being specific about selection principles, producers can raise the correct replacement heifers for the herd to optimize profitability. Genomic testing enables seedstock and commercial beef producers to make more informed decisions, and with more than confidence, and capitalize on animals with superior genetic merit.

Genotyping females can help producers know where their heifers are genetically, so that they will be able to make bull option with more confidence (Pryce and Hayes, 2012). Focusing on profitability indexes that include health traits, performance, carcass quality, and maternal traits, the commercial herd as well as the pure breed herd will steepen the genetic progress curve and herd will exist more than profitable, creating meliorate genetics long term. Genomic testing is that borderland that allows u.s.a. to get the almost value with the least corporeality of inputs through smart selection pressures.

It is important to keep in mind that success in the cattle business concern is a function of both genetics and phenotype. The best genetics may still occasionally produce offspring with poor anxiety and legs that will not concord up well in pasture or feedlot systems. Understanding how and where the herd is excelling and where changes need to be made can help producers make improvements. Keep in mind that single trait selection, selecting, for instance, solely on milk production, is usually a disaster. Cattle genetics must be selected to fit the environment and production practices of the operation or the operation they volition be marketed to. Know what your market wants and learn how to provide the type of cattle that fit that market by applying advisable selection principles.

Summary

For seedstock producers, genomic testing is a no-brainer and the mode of the future. The adoption of this technology by seedstock producers has already begun to determine their success in the market. For commercial cattlemen, every bit genomic testing costs proceed to drop, genotyping females should get increasingly popular to capture extra value.

Herds with a superior genetic contour have a fundamental advantage over other herds and, in many cases, will outperform their contemporaries over their lifetime. When young animals are role of a genetic improvement program, the use of GE-EPDs on the bull side and genomic testing on the heifer side are critical. Using good pick techniques will allow producers to select and develop the correct replacement heifers and consistently mate them to complementary sires to optimize profitability.

Implications

Call up, EPDs need to be used in conjunction with operation goals and resource. Limited available feed may limit the how aggressively you select for traits that requires a great deal of inputs and knowing what creates value for your marketplace will outcome in focusing on traits that are relevant. Your genetic parameters may be different from someone else based on your environment, and then focus on your needs. Remember, cattle must nonetheless be audio structured and reproductive to terminal, grow, and reduce your workload. A balanced approach is crucial for a sustainable enterprise, and that includes making sure that your genetics yet match your system with desired physical features that will final in your system and encounter buyer demand.

Bibliography

American Angus Clan. 2020. Combined Value Index - Dec 13, 2019 Update Accessed on April 21^st, 2020.

American Angus Association. 2020. Value Indexes. Accessed on April 21^st, 2020.

American Hereford Association. 2020. Trait Definitions. Accessed on April 21^st, 2020.

American Simmental Clan. 2020. Quick Reference to ASA EPDs and $ Indexes. Accessed on Apr 21^st, 2020.

Beef Sires by Breed. 2020. Accessed on Apr 16^th, 2020.

Beef Sires Catalog. 2020. Accessed on April 16^thursday, 2020.

Garrick, D. J., Golden, B. L. 2009. Producing and genetic evaluations in the U.s. beefiness manufacture of today. J. Anim. Sci. 2009, 87: E11-E18. DOI: 10.2527/jas.2008-1431.

Kuehn, L., and Thallman, Thou. 2019. Across-Breed EPD Table and Improvements. Accessed on April 15^th, 2020.

Philipsson, J., G. Banos, and T. Arnason. 1994. Nowadays and futurity uses of selection index methodology in dairy cattle. J. Dairy Sci.77:3252–3261. DOI: 10.3168/jds.S0022-0302(94)77266-0

Pryce, J., Hayes, B. 2012. A review of how dairy farmers can use and profit from genomic technologies. Animate being Production Science 52, 180-184.

Rolf, M. Yard., Decker, J. East., McKay, South. D., Tizioto, P. C., Branham, K. A., Whitacre, L. Thousand., Hoff, J. L., Regitano, L. C. A., Taylor, J. F. Genomics in the United States beef industry. Livest Sci. 2014;166:84–93. DOI: x.1016/j.livsci.2014.06.005

Van Eenennaam A. L., Drake D. J. 2012. Where in the beef-cattle supply chain might DNA tests generate value? Anim. Prod. Sci. 52:185–96. DOI: 10.1071/AN11060

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Source: https://extension.psu.edu/understanding-epds-and-genomic-testing-in-beef-cattle

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