EPD’s are an estimate of an animal’s genetic worth for that particular trait. An EPD is expressed in the units of measure for that trait. EPD’s are based on a combination of performance information from an animal’s pedigree, individual and progeny performance. EPD’s can be used to predict one animal’s progeny performance compared to another’s progeny. EPD’s can also be used to compare the genetic worth of one animal to the overall Hereford population average and distribution. Each calculated EPD has an associated accuracy value.
An accuracy value calculated by the genetic analysis is a number between 0 and 1. Accuracy is a relative indicator of the confidence you can place in that particular EPD. The closer an accuracy is to one, the more reliable is the estimate.
Accuracy ranges from 0-99% and indicates the probability of an EPD changing with the addition of more progeny data. The magnitude of possible change decreases as accuracy increases. Accuracy below 75% should be regarded as low, between 76-90% as medium and above 90% as high.
An EPD with an accuracy of “P” is “Pedigree Estimate” and is simply the exact average of that animal’s parents. An EPD with an accuracy of “P+” is an “Interim EPD” and is the parental average adjusted by the animal’s individual performance compared to his contemporaries.
Accuracy is based on the amount of performance information available on the animal and its close relatives – particularly the number of progeny analyzed. Accuracy is also based on the heritability of the trait and the genetic correlations with other recorded traits. Hence accuracy indicates the “confidence level” of the EPD.
|Regn. No:||The Association Registration Number of the animal.|
|Name:||The registered name of the animal.|
|Calving Ease – Direct (CE):||CE EPDs are based on calving ease scores and birth weights. More positive EPDs are favorable and indicate easier calving. The EPD for direct calving ease indicates the influence of the sire on calving ease in purebred females calving at two years of age.|
|Birth Weight (BW):||The BW EPD is an indicator of birth weight and calving ease. Progeny sired by a bull with a BW EPD of 2.2 can be expected to weigh 3.2 lb. more at birth, on average, than progeny sired by a bull with an EPD of -1.0 lb. (2.2 minus -1.0 = 3.2 lb.) Birth weight is another indicator of calving ease. Larger BW EPDs usually, but not always, indicate more calving difficulty.|
|Weaning Weight (WW):||The WW EPD reflects pre-weaning growth potential. Measured from adjusted 205-day weight. It is an indicator of direct genes for growth independent of milk production of the dam. Calves sired by a bull with a WW EPD of 30 should have a 20 lb. advantage in 205-day adjusted weaning weight compared to calves sired by a bull with an EPD of +10 lb. (30 minus 10.0 = 20 lb.).|
|Yearling Weight (YW):||YW EPD for a sire with an EPD of 87 indicates that on average, his progeny should be 30 lb. above the average of progeny of a bull with an EPD of 57 lb. YW EPD reflects differences in the 365-day adjusted yearling weight for progeny. It is the best estimate of total growth.|
|Maternal Milk (MM):||The MM EPD is a prediction of weaning weight differences due to milk and maternal ability of the dam. For a sire, the MM EPD predicts the maternal ability of his daughters expressed in pounds of calf weaned. MM EPD’s do not specifically predict pounds of milk produced, but pounds of calf weaned due to maternal production of the dam. It predicts the difference in average weaning weight of sires’ daughters’ progeny due to milking ability. Daughters of a sire with a MM EPD of 14 should produce progeny with 205-day weights averaging 24 lb. more (as a result of greater milk production) than daughters of a bull with a MM EPD of -10 lb. (14 minus -10.0 = 24 lb.). This difference in weaning weight is due to total milk production over the entire lactation period.|
|Maternal Milk & Growth (MG):||The MG EPD is a combination EPD. It is the MM EPD plus 1/2 the WW EPD. It has no accuracy value since it is simply a combination of two other EPD’s. A sire’s MG EPD reflects what he is expected to transmit to his daughters for a combination of both growth genetics (WW EPD) and maternal production (MM EPD). This EPD is sometimes referred to as “total maternal” or “combined maternal.”|
|Maternal Calving Ease (MCE):||The MCE EPD indicates how easily a sire’s daughters will calve at two years of age. When compared to the daughters of other sires.|
|Scrotal Circumference (SC):||Measured in centimeters and adjusted to 365 days of age, SC EPD is the best estimate of fertility. It is related to the bull’s own semen quantity and quality, and is also associated with age at puberty of sons and daughters. Larger SC EPDs suggest younger age at puberty. Yearling sons of a sire with an EPD of 0.7 should have yearling scrotal circumference measurements that average 0.7 cm. larger than progeny by a bull with an EPD of 0.0. In this genetic analysis, a multiple-trait model was used for scrotal circumference. Weaning weight was used as a predictor variable to increase the prediction accuracy of SC EPDs. Therefore, an animal with a weaning weight EPD should also have an SC EPD.|
|Rib Fat (FAT):||The FAT EPD reflects differences in adjusted 365-day, twelfth-rib fat thickness based on ultrasound measurements of live yearling cattle. Sires with low, or negative, FAT EPDs are expected to produce leaner progeny than sires with higher EPDs. Ultrasound measures have been shown to be highly correlated with the performance of slaughter progeny.|
|Ribeye Area (REA):||REA EPDs reflect differences in an adjusted 365-day ribeye area measures based on ultrasound measurements of live yearling cattle. Sires with relatively higher REA EPDs are expected to produce better muscled and higher percentage yielding slaughter progeny than will sires with lower REA EPDs|
|Intramuscular Fat (IMF):||IMF EPDs reflect differences in an adjusted 365-day intramuscular fat (marbling) score based on ultrasound measurements of live yearling cattle. Breeding cattle with higher IMF EPD’s should produce slaughter progeny with a higher degree of intramuscular fat and therefore higher quality grades.|
Profit indexes are not silver bullets! The four indexes which have been formulated by the AHA are to be used to assist Hereford breeders in using the genetic evaluations to potentially improve profitability for commercial producers. These indexes have been designed using multiple traits. These indexes are formulated on general representations of beef production systems used in the U.S. and consider a group of economically relevant traits that characterize those systems. Relative economic values for this group of traits are paired up with the EPD to produce a $ index value. The difference in the $ value of the index predicts the difference in profit. Each of the indexes utilizes crossbreeding to capture the value of hetorosis. The indexes also include cost of production for all phases of production (cow-calf, feedlot and harvest). The income is derived at the carcass endpoint based on quality, weight and grade and yield. The economic values are based on past values with some forecast for what economists believe the future holds. The economic values assigned to each trait can be changed at anytime that it looks to be necessary.
|BMI Index||The Baldy Maternal Index is a maternally focused index that has a production system based off of 1000 Hereford x Angus females with a progeny harvest endpoint directed towards CHB. This index is more critical of CE than the Brahman Influence Index and also has significant weight on fertility. There is positive weight on WW and a slightly negative weight on YW which promotes early growth and then a slow down on growth to keep mature size manageable. The weight for IMF is greater than the weight for REA. This is true because of the price difference between the choice-select spread and the fact that there is very little incentive to produce cattle better than a yield grade 3. The question comes up concerning the fact that our branded beef program (CHB) has been successful because of the acceptance of Select cattle. In answer to this, we are using a crossbreeding production system that could sell cattle on several grids and that our CHB program is installing a choice product. This index is geared to service any commercial program that runs British cross cows.|
|CEZ Index||The Calving Easy Index is a general purpose index that focuses on identifying bulls that can be used on heifers and then ultimately the calves will be marketed through CHB. As you might expect, CE and MCE has significant weight in this index along with fertility. There is very little weight put on growth traits and less emphasis on carcass. Remember, this is a general index that is specifically designed to be used in a heifer program.|
|BII Index||The Brahman Influence Index is a maternally focused index that is based off of a 1000 head cow herd of Brahman x Hereford cross cows. The progeny for this index will be harvested in a commodity based system since CHB does not allow Brahman influenced cattle into the program. This index has less emphasis for CE than any of the other indexes. There is emphasis on both REA and IMF since the cattle will be harvested through a commodity market. The largest emphasis in this index is in fertility which is measured solely by Scrotal Circumference at the present time. Obviously, the target for this index is the producers in the Southern regions of the US where the bulls are typically sold to commercial cattlemen that have Brahman Influenced cow herds.|
|CHB Index||The CHB Index is a terminal sire index that is built on a production system where Hereford bulls sire calves for the CHB market. There is some pressure put on CE and then positive weight on both WW and YW. Remember that all offspring in this index are harvested, so we want them to be born alive and then grow fast at all stages of life. Of course, we have a much heavier weight value on fat in this index, as we want the cattle to stay lean. There is also a significant weight on both REA and IMF with more emphasis again on IMF. This index would be used by producers who have a target of producing bulls for a terminal breeding program. This index could be used heavily in the Midwest where bulls are used in rotational breeding programs to produce cattle in a retained ownership program or simply sold to backgrounders. This is the only index that has no emphasis on fertility. Remember that nothing is retained in the herd.|
When you see the following displayed below the EPD table in your search results:
BW:72/306, WW: 70/287, YW: 33/116, SC: 6/35, Dgt: 32, Fat: 34, REA: 15, IMF: 3
Here is what it means:
|BW: 72/306||“72″ is the number of herds in which progeny were raised with recorded birth weight measurements. This includes herd counts from AHA & CHA. Number of herds gives a general indication of progeny distribution for each of the traits.|
|“306″ is the number of progeny out of the animal with recorded measurements for each specific trait. This includes the progeny counts from AHA & CHA. Number of progeny should not be used in lieu of accuracy, but simply to further clarify accuracy values.|
|Dgt: 32||The number of daughters sired by the bull which have produced progeny with weaning weight records. This includes the daughter counts from AHA & CHA. Number of daughters should not be used in lieu of accuracy, but simply to further clarify Maternal Milk and Maternal Milk & Growth accuracy values.|
|REA: 15||The number of scan progeny recorded for each of the carcass traits.|
These statistics are calculated at the time of each genetic analysis. Therefore, they will only be updated when new EPD results are reported.