Body measurements, metritis, and postpartum performance of first lactation cows.

Effects of herd, sire, season, body height, BW, age at calving, and metritis on future performance of first lactation cows were evaluated in eight commercial Israeli Holstein herds. Short, heavy first lactation cows had an odds ratio of 3.1 of incidence of metritis at calving compared with all others; 648 first lactation cows were measured at wk 1 postpartum. Sire, herd, age, height, season, and BW contributed to peak milk yield. Metritis did not affect peak yield. Herd, sire, height, and age contributed to mature equivalent corrected 305-d milk yield. No effect was found for BW, season, or metritis. Herd was the only variable contributing to month of peak yield and rate of monthly drop in yield. Interactions between BW, height, and incidence of metritis were significant. Tall, heavy first lactation cows with metritis peaked higher and yielded more than those without metritis. Short, light first lactation cows with metritis yielded less and peaked lower than their healthy counterparts. Metritis did not affect future fertility, but season and the interaction between BW and height did. Tall, heavy first lactation cows had a lower pregnancy rate from first AI, independent of milk yield. The relative importance of height as a predictor of future milk yield is underestimated. The interaction between height and BW may have an antagonistic effect on yield and fertility.