season: control 4/13 = 30.8% vs. IGF-1 1/17 = 5.9%; hot season: control 5/38 =

13.2% vs. IGF-1 10/30 = 33.3%) and live calving rate (cool season: control 4/13 =

30.8% vs. IGF-1 1/17 = 5.9%; hot season: control 5/38 = 13.2% vs. IGF-1 9/29 =

31.0%). Among recipients that received embryos that were cultured in 5% 02 and

harvested on day 7, there was a numerical interaction between season and embryo

treatment for both overall calving rate and live calving rate but these differences were not

statistically different (Table 4-2).

 When data were analyzed from the cool season only, there was no effect of IGF-1

on overall calving rate or live calving rate (Table 4-1). However, when data from the hot

season were analyzed separately, IGF-1 tended to increase both overall calving rate (P <

0.06) and live calving rate (P < 0.09). When data were analyzed separately for each

treatment group, recipients that received IGF-1 treated embryos tended (P < 0.10) to have

a higher overall calving rate in the hot season compared to the cool season, but there was

no difference in live calving rate. For control embryo recipients, there was no significant

effect of season on either overall or live calving rate although, numerically, calving rates

were greater for the cool season.

Pregnancy Loss

 Pregnancy loss was 52.8% (96/182) between day 21 and day 30 of gestation. A

total of 10.8% (10/93) and 20.4% (10/49) of pregnant recipients lost their pregnancies

from day 30 to day 45 and day 45 to term, respectively.

 There was an interaction (P < 0.01) between season and embryo treatment

affecting pregnancy loss from day 21 to ay 30. Pregnancy loss in the cool season was not

different between recipients that received control versus IGF-1 embryos but recipients in