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GENEX Proprietary Health Traits for Jerseys

Building a Healthier Jersey Herd

The proprietary health traits for Jersey cattle were released in December 2017 and incorporated into the ICC$ index for Jerseys. Both breeding values are set to a base of 100, with values greater than 100 leading to reduced incidence of the health concern.


Age at First Calving (AAFC)

Age-at-First-Calving-AAFC.jpgDevelopment of the AAFC breeding value highlights the importance of daughter fertility within the Jersey breed. Why is it important? Lowering age at first calving has a positive impact on profitability through improved fertility, higher milk production and limited impact on stillbirths.1 Therefore getting heifers calved in early equals bottom-line profit.

AAFC is a component of the Fertility (FERT$) sub-index within the ICC$ index. When specifically looking to improve herd fertility, choose sires based on ICC$ and then the FERT$ sub-index. Higher AAFC values are indicative of the sire’s daughters growing and maturing faster and being reproductively viable at a younger age. For instance, one can expect about a 44-day difference in age at first calving between daughters of a 105 AAFC sire and daughters of a 95 AAFC sire.

AAFC is calculated in collaboration with Cooperative Resources International (CRI) International Center for Biotechnology (ICB) research scientists using the CRI dairy research database. The database contains 54 million health records on nearly 12 million cows. AAFC heritability is 18.7%. 

Calf Survivability (CSRV)
Calf-Survivability-CSRV.jpgThis health trait brings awareness to the genetics that instill hardiness and survivability in newborn calves, which is a continual area of concern within the Jersey breed.

CSRV is reflective of the percent of female calves that survive past 120 days of age (excludes calves sold). Demonstrating the trait’s significance, the CRI research database shows that approximately 6.5%of Jersey calves die between days 2 and 120 of age.2

When selecting for CSRV as part of the ICC$ index, expect about a 5.5% difference in calf survivability between daughters of a 105 CSRV sire and daughters of a 95 CSRV sire.

CSRV is calculated by CRI ICB research scientists using the CRI dairy research database consisting of 54 million health records on nearly 12 million cows.

1 J.L. Hutchison, P.M. VanRaden, D.J. Null, J.B. Cole, and D.M. Bickhart. Journal of Dairy Science, Volume 100, Issue 8, 2017, 6853–6861
2 AgSource Dairy records, January 2012 to July 2017.