You have hopefully heard that GENEX released an Ideal Commercial Cow (ICC$) index for Jerseys with the December 2017 sire summaries, and you may have noticed mention of two proprietary traits included in the index. So what are they and what do they measure? Read on as our U.S. Dairy Marketing Manager and Jersey farmer herself, Leah James, helps us explain.
GENEX has released Calf Survivability (CSRV) and Age at First Calving (AAFC) evaluations to
address critical areas of concern within the Jersey breed.
“CSRV brings awareness to genetics that instill hardiness and survivability in newborn calves,” explains Leah.
“AgSource Dairy data for a five-and-a-half-year period from January 2012 through July 2017 shows that 6.5% of Jersey calves died between 2 and 120 days of age,” adds Leah. “The new CSRV breeding value, included in the Sustainability subindex of the Ideal Commercial Cow index for Jerseys, aims to provide genetic selection to improve the survivability of Jersey calves.”
The CSRV breeding value, available on all GENEX sires, reflects the percent of female calves that survived past 120 days of age. The breeding value is set to a base of 100, meaning 100 is average. Expect about a 5.5% difference in calf survivability between daughters of a 105 CSRV bull and daughters of a 95 CSRV bull. CSRV has an 8.1% heritability.
The second trait, AAFC, highlights the importance of daughter fertility among Jersey cattle.
“In surveying some of our Jersey customers, it was clear that getting heifers calved in early is a point of focus, especially considering the negative trend for daughter fertility over the past 50+ years,” notes Leah. “AAFC aims to get heifers calved in early because that equals bottom‑line profit for the dairy.”
The AAFC breeding value is indicative of the heifer growing and maturing faster and being reproductively viable at a younger age. It is included within the Fertility sub-index of the Ideal Commercial Cow (ICC$) index for Jerseys.
The breeding value is set to a base of 100. Expect about a 44-day difference in age at first calving
between daughters of a 105 AAFC bull and daughters of a 95 AAFC bull. Heritability is at 18.7%.
All GENEX proprietary health traits are calculated by the CRI ICB using the CRI dairy research database, which includes:
› Genomic profiles
› On-farm records
› Real-time production values
The database continues to grow and currently includes over 54 million health records on nearly
GENEX proprietary traits are set to a base of 100, meaning a breeding value of 100 is average. 12 million cows.
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