Table 1 Descriptive statistics within parity and time to conception of study sample with calving season July to September, average of 8.69 MJ to 12.83 MJ of daily energy from concentrates and no records of veterinary treatments throughout lactation, of Norwegian dairy cattle during the period 2005 to 2007.
N lactations | Mean age at calving in months (95%CI) | Lactations with early conception (43 to 93 DIM) | Lactations with late conception (after 93 DIM) | |||||
|---|---|---|---|---|---|---|---|---|
N lactations | Calving to first insemination in days (95%CI) | Number of inseminations | N lactations | Calving to first insemination in days (95%CI) | Number of inseminations | |||
First parity lactations | 12,758 | 25.48 (25.42-25.53) | 6,883 | 69.84 (69.51-70.17) | 1.27 (1.25-1.28) | 5,875 | 97.21 (96.49-97.92) | 2.12 (2.10-2.15) |
Second parity lactations | 5,651 | 37.63 (37.54-37.73) | 3,131 | 70.23 (69.73-70.72) | 1.25 (1.23-1.26) | 2,520 | 98.01 (96.89-99.12) | 2.02 (1.98-2.06) |
Third or later parity lactations | 4,640 | 58.401 | 2,574 | 70.99 (70.46-71.52) | 1.25 (1.23-1.27) | 2,066 | 97.94 (96.69-99.18) | 2.00 (1.96-2.05) |
All lactations | 23,049 | 35.101 | 12,588 | 70.17 (69.93-70.42) | 1.26 (1.25-1.27) | 10,461 | 97.54 (97.00-98.09) | 2.08 (2.05-2.10) |