Mature body weight and profit selection in Spanish dairy cattle

Individual mature body weight (BW) and profit were obtained from type, milk yield, and economic data from 42,401 Spanish Holstein cows. The economic value of BW was estimated in order to consider it in the breeding goal and to compare the importance of BW to other traits related to profit. Also, relationships between predicted breeding values (BV) of BW with actual profit, functional herd life, and calving interval by regression analysis were estimated. Body weight obtained an economic value of − 0.84 euros per cow per year. Inclusion of BW in the breeding goal by considering stature in a new economic index was shown to have 10% importance in genetic merit of profit. Reliability increased from 0.33 to 0.47 with respect to the old index that only included production and longevity. A significant positive quadratic relationship between body weight BV and profit BV was found (R2 equals to 0.54) but heavier animals had shorter herd lives and longer calving intervals. Influence of Holstein genes and selection for production increased body weight BV and reached a plateau at year 1994, while profit BV trends were still rising. Results suggest that selection for actual profit should be made maintaining a constant BW.