Field-testing $beef in Purebred Angus Cattle

Expected progeny differences (EPDs) have been applied to improve the genetics of beefiness cattle for well-nigh 4 decades. Expected progeny differences are predictions of the genetic transmitting ability 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 past producers to breed associations from an creature's bodily functioning, operation of progeny, functioning 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 as a Genomic-enhanced EPD (GE-EPD). Thus, in add-on to pedigree, performance and progeny data, GE-EPDs utilize genomic exam for increased reliability of an fauna's EPD (Eenennaam and Drake, 2012; Rolf et al., 2014).

Source: American Angus Association

Combined with all bachelor sources of information, GE-EPDs are the all-time estimate of an fauna'south genetic value as a parent. Genomics let better accuracies for younger animals and allows a clear picture of genetic traits of interest, particularly those that are expensive to measure such every bit feed efficiency, carcass traits in breeding stock, reproductive traits or maternal traits in bulls.

When a producer buys a young bull that has GE-EPDs, he is ownership with the aforementioned level of conviction in that creature equally one that has already sired between 10 and 36 calves, depending on the trait. In this way, GE-EPDs increase accurateness in those animals much earlier in their lives. With all these benefits, go on in heed that genomically-enhancing the EPDs does non change how the EPD can exist used, information technology merely increases its accurateness.

Table 1. Progeny Equivalents (PE) – Carcass trait PE equate to bodily carcass harvest data, not ultrasound scan equivalents.

Trait	PE
Calving Ease Direct	26
Nascency Weight	23
Weaning Weight	27
Yearling Weight	23
Dry Matter Intake	12
Yearling Acme	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	eleven
Carcass Ribeye	17
Carcass Fat	fourteen

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

EPD Accuracy

Accuracy (ACC) reflects the precision of a prediction for a given fauna'due south EPD and provides us with a level of confidence for that animal'south genetic merit. Bulls with greater accuracy values may exist chosen "proven sires."

The EPD prediction of genetic merit for a trait is the best indicator of expected functioning of futurity progeny, which is expressed as departure from the population'due south base value. Recognizing that base values may be different among breeds is important; some breeds use an average inside a specific yr, whereas other breeds use a nonspecific historical betoken.

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

The lack of confidence associated with EPDs on young cattle comes from not having progeny or performance information, both of which increment the accuracy of the EPD. In young bulls, for example, near of their genetic value is based on their pedigree. As these animals age and have offspring, we know more and more virtually their genetic merit. This increased conviction is denoted by an increment in the accuracy value (0–1 calibration) associated with each EPD. It does non necessarily hateful that the EPD increases if accurateness increases. Information technology just means the EPD becomes closer to the true value, whether it increases or decreases. Think that EPD stands for expected progeny difference. Genotyping a young fauna increases accuracy because SNP genotypes have like value to evaluating additional progeny.

How to Utilise EPDs

Earlier getting started with EPDs, producers should define their specific production goals showtime and then select based on the EPDs that volition all-time allow them to see 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 use EPDs based on the pick of convenance bulls that meet their personal production goals.

Here are some traits that can exist 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 Direct (CED);
• Weaning Weight (WW);
• Yearling Weight (YW).

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

For producers who retain replacement heifers, the post-obit EPDs are ofttimes used in add-on to the previous list:

• Calving Ease Total Maternal (CETM), Calving Ease Maternal (CEM) or Maternal Calving Ease (MCE);
• Milk Production (Milk) or Maternal Milk (MM);
• Total Maternal (TM), Maternal Weaning Weight (MWW) or Maternal Milk and Growth (M&Grand);
• Mature Weight (MW) or Mature Moo-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 condign valuable dams in the herd.

Producers who raise their own animals through the feedlot volition ofttimes focus on the traits below, in addition to the maternal traits previously mentioned:

• Carcass Weight (CW) or Hot Carcass Weight (HCW);
• Fat (Fatty) or Back Fat (BF);
• Marbling (MB, MRB or MARB)
• Yield Grade (YG);
• Shear Strength (SHR);
• Rib-Heart Surface area (REA or RE).

In this instance, the traits selected are value traits for cattle marketed at the stop of life.

Case 1 of Using EPDs for Bull Selection

In this instance, a producer is looking for a Charolais balderdash to use on black Angus-influenced cows that have had at to the lowest degree 2 calves. In this case, the producer is using the Charolais in what is called a terminal cross, all calves being sold at weaning or after a backgrounding flow for slaughter. The producer wishes to maintain calving ease and accept the benefit of enhanced weight at the time of auction. Based on the tabular array beneath, which balderdash would be more advisable for the stated purpose based on EPD values?

Tabular array one. Charolais bullsⁱ for use on mature crossbred females.

Balderdash	CE	BW	WW	YW	MCE	MILK	SCR	CW	REA	Fat	MARB
A	11.vi	-4	27	58	iii.9	23	one.1	xx	0.66	0.041	0.18
B	two.9	3	59	99	two.2	1	2.ane	49	0.96	0.041	0.22
Breed Average	3.1	0.7	24.4	43.8	4	7.9	0.6	14.seven	0.26	0.002	0.04

^aneBulls information retrieved from Select Sires Beef and Genex.

With the focus on this phase of product, emphasis should be given mainly to 3 traits: CE, BW, and WW. We are assuming that these bulls are most likely young and have low accuracies, or are not proven.

Calving ease (CE) relates directly to the bull'due south pressure on birth weight. Balderdash B is expected, on boilerplate, to have 8.7 per centum fewer unassisted births when bred to 2-twelvemonth-one-time heifers than Bull A (a disadvantage if breeding to heifers). Balderdash B has an expected birth weight that would be 7 pounds heavier, on average, than Balderdash A. Thus, while clear that Balderdash A would be more appropriate for breeding heifers, our producer is interested in breeding multiparous cows. Therefore, considering bull B has a BW EPD that is only 2.3 lb. heavier than the breed average, the producer likely volition desire to put their emphasis on other traits. Exam of the WW EPD indicated that Bull B would be expected to produce calves that are 32 pounds heavier at weaning, on average, than Bull A. This departure is what usually drives sales and profits at weaning. Thus, if the producer decides to sell calves at weaning time, Bull B may be the appropriate choice. In improver, while maybe not as important if the producer sells at weaning, this producer may also want to wait at YW and some carcass traits when selecting their bulls. In this case the logic is that selling high quality calves at weaning that will perform well effectually yearling age and through the feedlot may create a reputation of raising loftier-value calves that are assisting for feedlot owners. Because this is a terminal cross, no heifers will exist retained, and maternal traits tin can be ignored.

Choice by Alphabetize

Now, in addition to private trait selection using EPDs, animals can also be selected on an "index". An economic index is a tool used to select for several traits at once based on a specific breeding objective. An economic index approach considers genetic and economic values as well every bit 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 effective than independent culling levels or sequential selection (Philipsson et al., 1994; Garrick and Golden, 2009).

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

From the American Angus Association (AAA, 2020):

• Beefiness Value ($B), an index value expressed in dollars per head, is the expected average difference in hereafter progeny performance for postweaning and carcass value.
• Combined Value ($C), expressed in dollars per head, is an index which includes all traits that make up both Maternal Weaned Calf Value ($G) and Beefiness Value ($B) with the objective that commercial producers will supercede 20% of their breeding females per year with replacement heifers retained within their ain herd.

From the American Hereford Association (AHA, 2020):

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

From the American Simmental Association (2020):

• All-Purpose Alphabetize (API) is an index that evaluates sires for use 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 course and yield.
• Terminal Index (TI) is an index that evaluates sires for utilize on mature Angus cows, with all offspring put on feed and sold on course and yield.

Example 2 of Using EPDs for Bull Pick

A producer is looking for an Angus balderdash to brood a straight-bred Angus herd. The producer plans to retain ownership of the females to apply in the breeding herd and sell the calves at weaning. Thus, maternal traits of the females volition be of import.

Tabular array ii. Angus bulls^ane for apply on straight-bred Angus females.

Bull	CED	BW	WW	YW	CW	Marb	RE	Fat	$K	$W	$F	$G	$B
A	16	-0.half dozen	68	129	62	1.8	1.11	-0.028	62	79	124	120	244
B	sixteen	-2.5	64	118	32	0.42	0.53	0.046	51	78	69	38	106
Breed Average2	3	ane	26	45	22	0.42	0.32	0.008	52	54	82	44	126

¹Bulls data retrieved from Select Sires Beef.
²Breed average retrieved from The American Angus Association.

To address the producer's goal as stated, nosotros can look at the Maternal Weaned Dogie Value ($M) because it provides an indication of expected maternal ability and profit based on sale of weaned calves. Bull A will produce calves that will profit, on boilerplate, $eleven more than Bull B using the $M. Bull A will be the better buy for this scenario where female memory and weaned calf value are both important.

Across-breed EPD Comparisons

Inside a breed, EPDs can be directly compared. Bulls of unlike breeds can also be compared, simply adjustment factors to the EPDs are needed because an EPD from 1 brood evaluation is non directly comparable to an EPD from some other brood evaluation. Since 1993, the U.S. Meat Animate being Research Centre (USMARC) has produced a tabular array of these adjustment factors so that the merit of individuals can be compared across breeds.

Example 3 of Using EPDs for Bull Selection

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

Table 3. DEPs from different breeds to use on a commercial crossbred herd.

Balderdash	CE	BW	WW	YW	Milk	DOC	YG	CW	REA	Marb
Simmental1	17.i	-3.9	68	95.seven	26.3	7.4	-0.22	28.2	0.58	0.35
Limousin1	14	1.7	61	xc	21	8	-0.73	sixteen	ane.23	viii

¹Bulls information retrieved from Select Sires Beef.

With the above information, the producer also needs to access the table below:

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

Brood	Birth Wt. (lb)	Weaning WT. (lb)	Yearling Wt. (lb)	Maternal Milk (lb)	Marbling Scorea	Ribeye Surface area (intwo)	Fatty 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	-16.5	-44.4	-12.5	-0.thirty	0.02	-0.073	-71.1
Cherry Angus	2.6	-19.four	-31.4	1.5	-0.03	0.25	-0.040	-thirteen.2
Shorthorn	4.five	-34.iv	-46.vi	-0.ane	-0.07	0.47	-0.032	5.6
South Devon	2.half-dozen	-29.nine	-55.4	3.one	-0.53	0.64	-0.213	-68.8
Beefmaster	iv.0	23.four	1.1	7.seven
Brahman	10.3	53.iii	fourteen.4	16.7		0.03	-0.166	-35.9
Brangus	3.1	fourteen.9	v.3	12.9
Santa Gertrudis	5.2	forty.4	39.8	xvi.8	-0.44	0.12	-0.085	-12.3
Braunvieh	2.2	-21.1	-46.6	4.1	-0.61	1.00	-0.100	-53.iv
Charolais	6.vi	32.vii	23.2	8.1	-0.29	0.79	-0.201	five.one
Chiangu	2.eight	-21.ane	-36.2	2.5	-0.47	0.59	-0.142	-19.3
Gelbvieh	2.9	-15.5	-27.i	8.2	-0.37	0.66	-0.066	1.5
Limousin	2.five	-16.9	-53.9	-2.four	-0.03	0.59	-0.024	-five.1
Maine-Anjou	ii.4	-30.3	-55.2	-seven.0	-0.43	0.95	-0.179	-35.one
Salers	0.9	-11.2	-48.0	v.vi	0.07	1.08	-0.177	-47.6
Simmental	ii.viii	-eleven.6	-nineteen.ii	1.8	-0.12	0.45	-0.049	-7.5
Tarentaise	ii.7	20.2	-12.1	15.vii

^aMarbling score units: 4.00 = s1°0; 5.00 = Sm00
Source: United states Meat Animal Research Center (2020) through Beef Improvement Federation.

With both tables of data, a table for beyond brood comparisons can exist made, like to Table 5.

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

Balderdash		BW (lb)	WW (lb)	YW (lb)	Milk (lb)
Simmental	EPDone	-iii.ix	68	95.7	26.3
	AB Adj. Factors2	2.eight	-11.6	19.ii	i.8
	AB-EPD3	-1.1	56.iv	76.five	28.1
Limousin	EPD1	1.7	61	xc	21
	AB Adj. Factorstwo	two.5	-16.9	-53.9	-ii.4
	AB-EPD3	4.2	44.1	36.1	18.half dozen

^aneEPDs are the within-brood EPD values from the brood's genetic evaluation for the bull of interest.
²AB adj. factors are the across-brood adjustment factors from Table 1.
^threeAcross-breed EPDs later adjustment factors are applied to within-breed EPDs.

The across-breed (AB) aligning factors for BW are 2.8 lb for Simmental sires and 2.5 lb for Limousin sires. The AB-EPD for that trait is -3.9 lb + ii.8 lb = -i.1 lb for the Simmental balderdash and 1.seven lb + 2.5 lb = 4.two lb for the Limousin bull. The expected birth weight deviation of offspring when both are mated to cows of another breed (e.1000., Angus) would be -1.1 lb - four.2 lb = -v.3 lb. At weaning, the Simmental bull volition produce heavier calves. This weight difference becomes more evident at yearling historic period, when the expected yearling weight of the Simmental bull offspring volition surpass the Limousin bull offspring by almost forty lb. On top of that, its daughters will produce, on average, 9.6 lb more than milk than the daughters of the Limousin bull. Therefore, the Simmental bull will exist easier on heifers (lower birth weight), provide faster growth pre- and mail-weaning, and have daughters that produce more milk.

Benefits of genomic testing females

Selecting females for replacement is one of the near challenging aspects of commercial cow-calf production. Also, heifer evolution is an expensive proposition. Therefore, producers may determine whether a given heifer can exist productive and profitable before she has had an opportunity to limited productivity associated with profitability, including fertility, calving ease, milking ability, growth and mature size. By using a good breeding strategy and existence specific most selection principles, producers can heighten the right replacement heifers for the herd to optimize profitability. Genomic testing enables seedstock and commercial beef producers to make more informed decisions, and with more confidence, and capitalize on animals with superior genetic merit.

Genotyping females can assist producers know where their heifers are genetically, and then that they will be able to make balderdash choice with more confidence (Pryce and Hayes, 2012). Focusing on profitability indexes that include wellness traits, performance, carcass quality, and maternal traits, the commercial herd every bit well every bit the pure breed herd will steepen the genetic progress curve and herd will be more than profitable, creating better genetics long term. Genomic testing is that frontier that allows usa to go the most value with the to the lowest degree amount of inputs through smart pick pressures.

Information technology is important to keep in mind that success in the cattle concern is a function of both genetics and phenotype. The best genetics may all the same occasionally produce offspring with poor anxiety and legs that will not hold up well in pasture or feedlot systems. Understanding how and where the herd is excelling and where changes need to be fabricated can help producers brand improvements. Go on in heed that single trait choice, selecting, for example, solely on milk production, is usually a disaster. Cattle genetics must exist selected to fit the environment and production practices of the operation or the functioning they will be marketed to. Know what your market wants and learn how to provide the type of cattle that fit that marketplace by applying appropriate choice principles.

Summary

For seedstock producers, genomic testing is a no-brainer and the fashion of the future. The adoption of this applied science past seedstock producers has already begun to make up one's mind their success in the market. For commercial cattlemen, as genomic testing costs continue to drop, genotyping females should become increasingly popular to capture actress value.

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

Implications

Think, EPDs need to exist used in conjunction with operation goals and resources. Limited available feed may limit the how aggressively you lot select for traits that requires a great deal of inputs and knowing what creates value for your marketplace will result in focusing on traits that are relevant. Your genetic parameters may be unlike from someone else based on your environs, so focus on your needs. Remember, cattle must still be sound structured and reproductive to concluding, grow, and reduce your workload. A balanced arroyo is crucial for a sustainable enterprise, and that includes making sure that your genetics all the same lucifer your organization with desired physical features that will last in your system and come across buyer need.

Bibliography

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

American Angus Clan. 2020. Value Indexes. Accessed on Apr 21^st, 2020.

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

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

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

Beef Sires Itemize. 2020. Accessed on April 16^th, 2020.

Garrick, D. J., Gilded, B. Fifty. 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, Fifty., and Thallman, M. 2019. Across-Brood EPD Table and Improvements. Accessed on April 15^th, 2020.

Philipsson, J., Grand. Banos, and T. Arnason. 1994. Present and hereafter 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 turn a profit from genomic technologies. Animal Product Science 52, 180-184.

Rolf, Chiliad. Yard., Decker, J. E., McKay, S. D., Tizioto, P. C., Branham, K. A., Whitacre, L. Yard., Hoff, J. L., Regitano, 50. C. A., Taylor, J. F. Genomics in the United states beef industry. Livest Sci. 2014;166:84–93. DOI: 10.1016/j.livsci.2014.06.005

Van Eenennaam A. L., Drake D. J. 2012. Where in the beef-cattle supply concatenation 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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