Status as of: 2014-09-02

Form GE

DESCRIPTION OF NATIONAL GENETIC EVALUATION SYSTEMS

Country (or countries)	United States of America	
Main trait group	Calving [calving ease (CE) – service sire and daughter, stillbirth (SB) – service sire and daughter]	
Breed(s)	BSW, HOL (B&W, R&W), JER (SB only); all breeds and first-generation crossbred calves evaluated together in a multibreed sire-MGS model	
Trait definition(s) and unit(s) of measurement	CE: Expressed as percentage of births of bull calves that are difficult in primiparous heifers (%DBH), where difficult births are scored as requiring considerable force or being extremely difficult (4 or 5 on a 5-point scale); service-sire CE measures tendency of calves from a particular service sire to be born more or less easily; daughter CE measures ability of a particular cow (daughter) to calve easily
SB: Expressed as percentage of births of bulls calves that are stillborn in primiparous heifers (%SB), where stillborn calves are scored as dead at birth or born alive but died within 48 hours of birth (2 or 3 on a 3- point scale); service-sire SB measures tendency of calves from a particular service sire to be stillborn more or less often; daughter SB measures ability of a particular cow (daughter) to produce live calves	
Method of measuring and collecting data	In recent years, scores reported almost entirely through Dairy Herd Information Affiliates 

CE: Scored by owner on a scale of 1 to 5, where 1 = no problems encountered or unobserved birth and 5 = extreme difficulty
SB: Scored by owner on a scale of 1 to 3, where 1 = calf born alive and still alive 48 hours after birth, 2 = calf born dead, and 3 = calf born alive but died within 48 hours after birth; scores of 2 and 3 combined into a single category for evaluation	
Time period for data inclusion	Calvings from 1980 and later	
Age groups (e.g. parities) included	All parities	
Other criteria (data edits) for inclusion of records	No multiple births; sire age of >18 months or <18 years on calving date; MGS age of <18 years on dam birth date; no herds with a single calving record or only difficult CE scores for Brown Swiss or Brown Swiss-Holstein crossbreds

CE: Data from herd-years with abnormal score distributions excluded (about 3% of data) based on a goodness-of-fit statistic for multinomial score distribution
SB: Herds with <5 reported calf deaths in database excluded	
Criteria for extension of records (if applicable)	None
	
Sire categories	All sires (AI and NS) evaluated together 	
Environmental effects, pre-adjustments 	None	
Method (model) of genetic evaluation	ST threshold sire-MGS model; CE and SB evaluated separately	
Environmental effects3 in the genetic evaluation model	Year-season (F), parity-sex (F), sire-MGS birth year group (F), MGS breed (F; CE only) (F), calf heterosis (F), HY (R) 	
Adjustment for heterogeneous variance in evaluation model	None	
Use of genetic groups and relationships	Inverse of relationship matrix calculated using sire, MGS, and sire-MGS birth year effects within breed	
Blending of foreign/Interbull information in evaluation	None	
Genetic parameters in the evaluation	See Appendix CA for h2 estimates
 
CE: Sire variance, 0.022; MGS variance, 0.016; sire‑MGS covariance, 0.009
SB: Sire variance, 0.008; MGS variance, 0.018; sire‑MGS covariance, 0.004	
System validation	Means and SDs for all variables calculated and examined overall as well as for each data submission; means for new bulls, changes for high bulls, largest changes, and key statistics for recent AI bulls checked	
Expression of genetic evaluations	CE: %DBH
SB: %SB

Values from underlying scales reported to Interbull	
Definition of genetic reference base

Next base change	HOL: Direct, bulls born in 2010; maternal, bulls born in 2005
BSW, JER: Direct, bulls born between 2006 and 2011; maternal, bulls born between 2001 and 2005

December 2019	
Calculation of reliability	Approximated by inverse of diagonal element of coefficient matrix	
Criteria for official publication of evaluations	Bull from AI organization that supports calving trait evaluation	
Number of evaluations/ publications per year	3 (April, August, December)	
Use in total merit index4	CE: 1.25%  (HOL) and 1.5% (BSW) for service sire and 0.75%  (HOL) and 1.5% (BSW) for daughter of total for net merit dollars* (NM$); 2% for daughter  in Total Performance Index (TPI, HOL)
SB: 0.75% for service sire and 2.25% for daughter of total for NM$* (HOL); 1% for daughter  in TPI (HOL)

*Calving traits included in NM$ as calving ability dollars (CA$) index with 5% (HOL) and 3% (BSW) of total emphasis	
Anticipated changes in the near future	None	
Key reference on methodology applied	Van Tassell, C.P., and G.R. Wiggans. 2002. Enhancing quality of dystocia data by integration into a national dairy cattle production database. Proc. 7th World Congr. Genet. Appl. Livest. Prod. 32:557–560. 
Wiggans, G.R., C.P. Van Tassell, J.C. Philpot, and I. Misztal. 2002. Comparison of dystocia evaluations from sire and sire-maternal grandsire threshold models. Proc. 7th World Congr. Genet. Appl. Livest. Prod. 32:561–564.
Wiggans, G.R., I. Misztal, and C.P. Van Tassell. 2003. Calving ease (co)variance components for a sire-maternal grandsire evaluation model. J. Dairy Sci. 86:1845–1848. 
Van Tassell, C.P., G.R. Wiggans, and I. Misztal. 2003. Implementation of a sire-maternal grandsire model for evaluation of calving ease in the United States. J. Dairy Sci. 86:3366–3373. 
Cole, J.B., R.C. Goodling, Jr., G.R. Wiggans, and P.M. VanRaden. 2005. Genetic evaluation of calving ease for Brown Swiss, Jersey, and Holstein bulls from purebred and crossbred calvings. J. Dairy Sci. 88:1529–1539. 
Cole, J.B., G.R. Wiggans, and P.M. VanRaden. 2007. Genetic evaluation of stillbirth in United States Holsteins using a sire-maternal grandsire threshold model. J. Dairy Sci. 90:2480–2488.
Cole, J.B., G.R. Wiggans, P.M. VanRaden, and R.H. Miller. 2007. Stillbirth (co)variance components for a sire-maternal grandsire threshold model and development of a calving ability index for sire selection. J. Dairy Sci. 90:2489–2496. 
Yao, C., K.A. Weigel, and J.B. Cole. 2014. Short communication: Genetic evaluation of stillbirth in US Brown Swiss and Jersey cattle. J. Dairy Sci. 97:2474–2480.	
Key organisation: name, address, phone, fax, e-mail, web site	Evaluation calculation and distribution:
Council on Dairy Cattle Breeding
10300 Baltimore Ave.
Bldg. 005, Room 304, BARC-West
Beltsville, Maryland 20705-2350, USDA
voice: 301-525-2006; no fax
e-mail: duane.norman@cdcb.us
web site: https://www.cdcb.us

Evaluation methodology:
Animal Improvement Program
Animal Genomics and Improvement Laboratory
Agricultural Research Service, U.S. Dept. of Agriculture 
10300 Baltimore Ave.
Bldg. 005, Room 306, BARC-West 
Beltsville, Maryland 20705-2350, USA
voice: 301-504-8334; fax: 301-504-8092 
e-mail: aipl.inquiry@ars.usda.gov
web site: http://aipl.arsusda.gov	

Form GE	Appendix CA

Parameters for national genetic evaluations for calving traits as provided to Interbull

Country (or countries):	United States of America	
Main trait group:	Calving Traits [Service-sire and daughter CE, service sire and daughter SB]	
Breed(s):	BSW, HOL (B&W, R&W), JER (SB only)	

Trait	h2	Genetic
variance	Official proof
standardisation formulaa	
Direct CE	0.086			
Maternal CE	0.048			
Direct SB	0.008			
Maternal SB	0.021			
a	Expressed as follows:
StandEval = ((Eval − a)/b) × c + d, where a = mean of base adjustment, b = SD of base, c = SD of expression (include sign if scale is reversed), and d = base of expression.