Altogether, seven breeding seasons, four in summer and
three in winter, were included in the experiment. Before
each season, 11 to 27 animals (mean 19) with a high
breeding value were selected into the AI program. In all,
90 animals were entered into the program an average of
1.8 times (a maximum of 4 times for 5 animals). Thus,
164 animal cases were included in the experiment, of
which 94 were on summer and 70 on winter seasons. Distributions
of the animal cases into parity and interval
between calving and entering the program classes are presented
in Table 1. The majority of the cows were suckling;
19 cows did not lactate