Abstract #288

# 288
Sire predicted transmitting ability for production and fertility traits in US organic Jersey cows.
G. M. Pereira*1, B. J. Heins1, L. C. Hardie2, C. D. Dechow2, 1University of Minnesota, West Central Research and Outreach Center, Morris, MN, 2Pennsylvania State University, University Park, PA.

The objective of this study was to determine the relationship between US organic Jersey cow performance and sire predicted transmitting ability (PTA) for production and fertility traits. Production and fertility data were provided by Dairy Record Management Services (Raleigh, NC), and sire PTA were from the December 2018 genetic evaluations from Council on Dairy Cattle Breeding (Bowie, MD). Data were from 5,461 cows sired by 814 A.I. bulls from 31 organic herds and spanned from 2012 to 2017. The mean 305-d mature equivalent (305ME) milk yield was 8,021 kg and mean combined fat and protein yield was 656 kg, mean SCS was 2.55, and mean days open was 136 d. Lactations greater than 5, herd-year-seasons with less than 5 records and herds with less than 40 cow records were removed. Daughter records with days open greater than 250 d were truncated to 250 d open. The PROC HPMIXED of SAS was used for statistical analysis, with the fixed effect of age group at calving within lactation group, and random effects of cow and herd-year-season. Daughter records of 305ME milk, fat, and protein production, SCS and days open were regressed on sire PTA for milk, fat, protein, SCS and daughter pregnancy rate, respectively. The regression coefficients on sire PTA for production were expected to be 1, and were 1.07 ± 0.06, 1.11 ± 0.07, 1.02 ± 0.07 (P < 0.01) for 305ME milk, fat, and protein, respectively, and 0.76 ± 0.12 (P < 0.01) for SCS. For days open, the regression coefficient on sire PTA was expected to be −4, and was −3.09 ± 0.39 d (P < 0.01) per unit PTA. The regression coefficients for production were similar to the expected coefficients, suggesting that US organic Jersey cows are expressing their genetic potential. The regression coefficient for days open was lower than the expected coefficient, suggesting a need for genetic improvement in fertility of US organic Jersey cows.

Key Words: Jersey, organic, sire predicted transmitting ability