Abstract #W114

# W114
Associations between maternal characteristics and health, survival, and performance of heifers.
M. R. Carvalho1, C. Aboujaoude*1, T. J. DeVries1, B. McBride1, E. S. Ribeiro1, 1Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada.

Our objective was to investigate whether health, survival and performance of heifers from birth up to first lactation are associated with parity and health status of the dam. Holsteins heifers (n = 2,669) were categorized as 1) daughters of primiparous cows that, consequently, were not lactating during gestation (Prim-NoL; n = 1,322); 2) daughters of multiparous cows that did not have any clinical diseases in the previous lactation (Mult-NoCD; n = 841); and 3) daughters of multiparous cows that had at least one clinical disease in the previous lactation (Mult-CD; n = 506). Clinical diseases included retained placenta, metritis, mastitis, lameness, digestive and respiratory problems. Data from daughters included genotypic and phenotypic characteristics at birth, morbidity, reproductive performance, and culling from birth up to 305 DIM of first lactation, and milk production in the first lactation. Orthogonal contrasts evaluated the effects of the parity of the dam (Prim-NoL vs. Mult-NoCD+Mult-CD) and clinical disease in the previous lactation (Mult-NoCD vs. Mult-CD). Compared with daughters of multiparous cows, Prim-NoL were lighter at birth (36 vs. 41 kg; P < 0.01), had better genetics for production traits (EBV for milk: 942 vs. 806 kg; P < 0.01), were less likely to leave the herd as a heifer (18 vs. 27%; P < 0.01) and as a first-lactation cow (11 vs. 15%; P = 0.02), less likely to have pregnancy losses as a heifer (9 vs. 14%; P < 0.01) and clinical diseases as a first-lactation cow (31 vs. 37%; P = 0.02), and had reduced performance in the first lactation when considering their genetic potential (adjusted 305-d yield: 11214 vs. 11400 kg; P < 0.01). Compared with Mult-NoCD, Mult-CD were less likely to have diarrhea as a heifer (20 vs. 26%; P = 0.02) and a clinical disease as a first lactation cow (32 vs. 40%; P = 0.02), but were also more likely to leave the herd as a heifer (32 vs. 24%; P < 0.01) even though genetic merit for production traits were similar. In conclusion, parity and health status of the dam in the previous lactation were associated with morbidity and performance of heifers, and might represent factors affecting developmental programming in utero.

Key Words: heifer, developmental programming