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Glossary for April 2008 ENR$ Calculations
(alphabetical order)
- "Best-fit" (for herd management level): Only
three levels of herd management are presented. Average
herd management is characterized by average conception rates (40%),
average heifer survival (about 90% of heifers born actually survive
to calve), average culling of pregnant cows (10% of pregnant cows
culled), average age at first calving (26 months), and average
calving interval (13 months). A cost of $1.50 per day for each
day open is assumed in the calculation of ENR$. Days open are
determined by a sire's estimated relative conception rate (ERCR)
and a producer's herd management level. If your management is
generally better than average (optimistic), pick above average.
If you can only wish that your management were average (pessimistic),
pick below average. If your herd situation doesn't quite
fit any of these, pick the best one ("best-fit"), or run the program
twice picking a different herd management level each time. Compare
how bulls rank in your two choices and pick the bulls highest
on both lists.
NOTE: Higher priced bulls rank higher for herds
with above average management than they do for herds with below
average management.
- Cheese Merit: Cheese merit (CM$) is a comprehensive
index for those producers that sell their milk in a cheese market.
- ENR$: ENR$ is an economic index (see definition
of index below) that estimates the expected net revenue from one
unit of semen for an AI sire customed for a producer's milk market
and herd management level. The starting point for ENR$ is Lifetime
Net Merit, Lifetime Cheese Merit or Lifetime Fluid Merit depending
on a producer's milk market. ENR$ considers the cost
of semen, the costs associated with a sire's estimated relative
conception rate (ERCR), as well as revenues and costs associated
with milk sales, feed, health, reproduction, and culling. Performance
of daughters and future generations of descendants are included
in the revenues and costs. Discounting of future revenues and
costs is given proper consideration since there is a time lapse
between the time the semen is purchased and the time a resulting
daughter enters the milking string. ENR$ is expressed relative
to the service from an average non-AI bull.
- ERCR: ERCR or estimated relative conception rate,
is a measure of conception rate of a service sire relative to
service sires of herdmates which is calculated by Dairy Records
Management Systems (DRMS). Only first services are used in an
Animal Model program similar to the one used to compute production
PTAs. Estimates are adjusted for the effects of each mate's early
lactation energy-corrected-milk production, lactation number,
stage of lactation, month of breeding, herd, year, birth year
of bull and the interaction between bull and herd. Since ERCR
has been proven to be an accurate predictor of future fertility,
it should be useful to a dairy producer when choosing service
sires. Because ERCR is determined from many services in many different
herds, it is believed to be more accurate in identifying high,
average, and low fertility bulls than a single herd estimate.
ERCR was calculated from the AI breedings of Holstein and Jersey
bulls in DHI herds that report to DRMS, AgSource in Wisconsin,
and AgriTech Analytics in California. Unless noted, breeding records
from the recent three years were used.
- Fluid Merit (FM$): Fluid merit (FM$) is a comprehensive
index for those producers that sell their milk in fluid markets.
- Index: Combination of two or more traits to get
a single value; more important traits are given more weight and
less important traits are given less weight. Many factors, including
economic values, are taken into account.
- LIMITED NUMBER (in Step 4): Unless you choose
to look at all April 2008 bulls, you can choose an upper or
lower limit for a trait to get a shortened list.
Examples:
1) choose an ENR$ minimum of 75 to get a list of bulls with ENR$
equal to or greater than $75,
2) choose a maximum %DBH of 10 to get a list of bulls with %DBH
of no greater than 10%. NOTE: Only can choose maximums for %DBH
(only Holsteins) and semen price.
- Net Merit (NM$): In November 2000 a revised Net
Merit (NM$), or more correctly Lifetime Net Merit, was put into
use by USDA. NM$ measures the accumulated net profit over the
lifetime of a bull's average daughter. This index was created
for producers who sell milk based on milk, fat, and protein components.
- % DBH (Percent Difficult Births in Heifers):
Percentage of difficult calvings (with some or considerable assistance
needed) expected for a sire's calves born from heifers in an average
herd. A score of 10 or lower for % DBH means less-than-average
calving difficulty. ONLY AVAILABLE FOR HOLSTEINS.
- % Rel %DBH (Percent Reliability for Calving Ease):
The accuracy of the %DBH. The closer the percent reliability is
to 100, the more confidence we have in the %DBH presented. Reliability
is primarily based on the number of calvings and herds represented
in the %DBH. ONLY AVAILABLE FOR HOLSTEINS.
- % Rel. Yield (Percent Reliability Yield): Reliability
measures the accuracy of PTA Yield. Percent reliability yield
is composed of the reliabilities of milk, fat and protein weighted
as they are in Net Merit $. The closer the percent reliability
is to 100, the more confidence we have in the PTA Yield presented.
Reliability is primarily based on the number of daughters and
herds for which Net Merit $ can be calculated.
- Productive Life (PL): An estimate of daughter
survival through seven years of age. Actual culling data from
USDA is combined with linear type data from the Holstein Association
to get the best estimate of productive life available. Proofs
from bulls with only young daughters are impacted more by the
type traits than bulls with older daughters.
- PTA (Predicted Transmitting Ability): The best
estimate of an animal's genetic superiority or inferiority.
- PTA Fat: PTA for butterfat production in pounds.
This figure compares the expected production of future mature
daughters. PTA Fat is expressed relative to an average cow born
in 1995. Example: a bull with a PTA Fat value of 75 will have
daughters that on average produce 25 more lbs. of fat than bulls
with PTA Fat of 50 lbs.
- PTA Milk: PTA for milk production in pounds.
This compares the expected production of future mature daughters.
PTA Milk is expressed relative to an average cow born in 1995.
Example: a bull with 2000 lbs. of PTA milk will have daughters
that on average produce 1000 lbs. more milk than a bull with 1000
lbs. of PTA Milk.
- PTA Protein: PTA for protein production in pounds.
This figure compares the expected production of future mature
daughters. PTA Protein is expressed relative to an average cow
born in 1995. Example: a bull with a PTA Protein of 60 will have
daughters that on average produce 20 lbs. more protein than bulls
with PTA Protein of 40 lbs.
- Sample codes (abbreviated Smp Cd in reports):
S-Stud Sample: Designates a bull in a standard (S)
progeny test program of an AI business. S-coded bulls must be sampled
by semen distributed to at least 40 herds qualifying for USDA genetic
evaluations. Sampling organizations cannot sample bulls with the
intention of leasing them to another organization.
O-Other Sample Programs: Miscellaneous programs.
NOTE: A bull without a sampling code designates that the bull was
proven initially or totally outside of the United States but his
semen is currently available in the United States.
- Semen Price: National price per unit of semen
as released by AI organizations. Prices may vary from region to
region. If the price per unit of semen changes, the ENR$ value
changes as well. Example: The national semen price is $15 but
you can purchase the semen for $10 per unit. The ENR$ value was
$50 with the semen price at $15. Add $5 to the old ENR$ to get
a new ENR$ value of $55 with the semen price at $10.
- Somatic Cell Score (SCS): The PTA for SCS is
used to improve mastitis resistance. Bulls with low PTA for SCS
(less than 3.0) are expected to have daughters with lower mastitis
than bulls with high PTA for SCS (greater than 3.5). Example:
Assume on average that 20% of the first lactation cows in a herd
have one or more clinical episodes in first lactation. Expect
about 15% of the daughters of a bull with a 2.8 PTA for SCS to
have one or more episodes in first lactation and about 25% of
the daughters of a bull with a 3.8 PTA for SCS to have one or
more episodes in first lactation.
Average first-lactation SCS for cows born in 2000 by breed were: 2.97 for Ayrshire, 2.94 for Brown Swiss, 3.31 for Guernsey, 3.09 for Holstein, 3.34 for Jersey, and 3.07 for Milking Shorthorn.
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