Table 1. Increased endometrial EGF concentrations between Days 1 and 6 of the estrous cycle in dairy cows a.
| Cow No. | Days after estrus |
Pregnancy |
||||||
| 1 | 2 | 3 | 4 | 5 | 6 | 1st AI | 2nd AI | |
| 1 | – | + | + | – | – | – | + | NA |
| 2 | – | – | – | – | – | – | − | − |
| 3 | – | – | – | – | – | – | − | − |
| 4 | – | – | + | + | + | – | + | NA |
| 5 | – | – | + | + | – | – | + | NA |
| 6 | – | – | + | + | – | – | + | NA |
| 7 | – | – | + | + | – | – | − | + |
| 8 | – | – | + | + | – | – | − | − |
| 9 | – | – | + | + | + | – | − | + |
| 10 | – | – | + | + | – | – | − | + |
| 11 | – | – | – | – | – | – | − | − |
| 12 | – | – | + | + | – | – | + | NA |
| 13 | – | – | + | + | – | – | − | − |
| 14 | – | – | + | + | – | – | − | + |
| 15 | – | – | – | – | – | – | − | − |
| 16 | – | – | + | + | – | – | ND | ND |
| 17 | – | + | + | – | – | – | ND | ND |
| 18 | – | + | + | + | – | – | ND | ND |
| 19 | – | – | + | + | – | – | ND | ND |
| 20 | – | – | + | + | + | – | ND | ND |
a Endometrial EGF concentrations of ≥ 4.7 ng/g tissue weight (+) were considered as increased levels based on a normal range on Day 3 of the estrous cycle determined using data from 99 fertile cows [3]. NA: not applicable. ND: not determined. Cows Nos. 16–20 were not inseminated in this study. Cows with odd and even numbers were subjected to repeated biopsies from position A to F and F to A, respectively (see Fig. 1).