Agri Kultuur January / January 2018 - Page 30

(a) (b) Figure 1. The effect of (a) herd and (b) calving year on interval traits for calving date to first service date (CFS) and days open (DO) specific strategies to maintain a DO interval of about 147 days. Subsequently, another data set was compiled using a commercial (DIMSSA) reproduction management programme. Reproduction records of about 45 560 lactations from 15 770 Holstein cows were obtained from 27 dairy herds. Fertility traits for heifers and similar fertility traits for cows as above, were derived. Herds were ranked using a ranking system for each trait, 1 being best and 27 poorest. The top and bottom three herds were subsequently identified. In Table 2 the mean reproduction management performance for all Holstein herds and the top and bottom 10% of herds are shown. Table 2. The mean reproduction management performance for 27 herds in comparison to the top and bottom 10% of all Holstein herds All Bottom Animals Parameters herds Top 10% 10% Heifers Age at first service (m) 17.7 14.5 23.8 First service before 15m of age (%) 30 68 0 First service before 18m of age (%) 61 89 7 Age at first calving (AFC) (m) 27.8 24.6 33.4 AFC before 24 m of age (%) 21 60 1 AFC before 27 m of age (%) 50 84 8 Cows Interval calving to first AI (d) 92 89 104 First service before 80 days-in-milk (%) 51 62 44 Services per conception 2.16 1.62 2.35 Interval days open (d) 140 112 164 Pregnant before 100 days-in-milk (%) 40 57 31 Pregnant before 200 days-in-milk (%) 81 90 72 AgriKultuur |AgriCulture 30