Gen_Def

Monitoring Genetic Defects

DNA marker tests provide new tools to more efficiently identify and monitor genetic defects. The American Simmental Association`s Genetic Abnormality Policy is a scientifically based approach to managing and ultimately reducing the incidence of genetic abnormalities in our herds. It leverages cutting-edge technology both from DNA testing and software development standpoint to identify and present information on the potential for an animal to carry genetic abnormalities.

Policy:

Sires and donor dams that fall into ASA’s carrier in lineage (CL) or risk population categories (PR) must be tested before registration certificates and EPDs are available on new progeny. If DNA is not available on a sire or donor dam in question, their progeny must be tested before registration certificates and EPDs are released. No testing is required on dams of natural calves.

The results of the test do not impact eligibility for registration of the an animal or its calves. The test requirement goes into effect when a DNA marker test becomes commericially available and the defect has been named by the Board of Trustees as a defect to be monitored.

Solutions Available to Meet Testing Requirements:

1. Provide test result documentation from a lab, breed association or ASA approved source.

2. If sire and/or donor dam has not been tested, complete required genetic testing.

3. If sire and/or donor dam is not available for testing, complete required genetic testing on offspring.

The genetic defects for which DNA marker tests are available AND on which ASA is monitoring are listed in the table below in red.

Code	Name	DNA Marker Test	Testing Required	Risk Population
AL	Albinism	not yet
AM	Arthrogryposis Multiplex (curly calf)	Yes	Yes	Angus
DW1	Dwarfism (Angus)	Yes
CA	Contractual Arachnodactyly (Fawn Calf Syndrome)	Yes	Yes	Angus
DD	Developmental Duplication	Yes	Yes
NH	Neuropathic Hydrocephalus (hydro, water head)	Yes	Yes	Angus
HT	Hypotrichosis (hairless)	not yet
IE	Ideopathic Epilepsy	not yet
OS	Osteopetrosis (marble bone)	Yes	Yes
PHA	Pulmonary Hypoplasia with Anasarca	Yes	Yes	MA,CA,SS
PR	Protoporphyria (photosensitivity)	not yet
TH	Tibial Hemimelia	Yes	Yes	MA,CA,SS

ASA`s TraitTrac System: genetic defect monitoring made easy

ASA`s coding system shows every animal`s current genetic defect status. As information new information is added to ASA`s records the TraitTrac system autuomatically update the genetic status of an animal and its descendants.

TraitTrac codes use to designate Genetic status of each defect
Code	Description	Testing Requirement
TF Tested Free	Tested Free of the genetic defect	none
PF Pedigree Free	Pedigree Free (not tested). All ancestors in question tested free (TF) of defect.	none
DF Documented Free	Documented Free (not tested). Documented Free from another breed association or authorized source.	none
AF Assumed Free	Assumed Free (not tested). No known carrier in lineage and less than 1/8 blood from a population with a significant incidence of the defect.	none
PR Population Risk	Population Risk (not tested). Has at least 1/8 blood from ancestors from a population with a significant incidence of the defect.	Sires and donor cows must be tested before (additional) calves can be reported
CL Carrier in Lineage	Carrier in Lineage (not tested). Has a carrier in pedigree without intermediary ancestor(s) Tested Free (TF).	Sires and donor cows must be tested before (additional) calves can be reported
TC Tested Carrier	Tested Carrier of the genetic defect	none

The genetic defect status for any animal can be viewed from the epd/pedigree display from Animal Search under Data Search. In addition, herd summaries with genetic defect status are available from Reports under Herd Mgmt. Keep in mind the only animals guaranteed to be free of an abnormality are those Tested Free (TF) category. For example, since animals coded as Assumed Free (AF) have not been tested there may by some risk they are carriers of a genetic defect. Also keep in mind that for untested animals the coding system relies on the accuracy of pedigree records.

Please note: Some foundation registered animals that are registered in another breed association are coded as PR when more information from the originating breed association would show the animal is not from any effected lines of cattle. These animals can be updated to a Documented Free (DF) status by getting acceptable documentation from the breed association.

For more information about genetic defects see these links: Genetic defects, ASA information page
	Congenital Defects in Cattle , Beef Cattle Handbook, Extension Beef Cattle Resource Committee.
	"Cowboy Genetics" - Written by Dr. Lana Kaiser and originally published in the 2006 May/June edition of the Maine-Anjou Voice
	Frequently Asked Questions