A chromosome ideogram of the first inbred generation can be seen below. The animal Cups chromosomes are black and grey whereas sow 400 chromosomes are white. Inbreeding in animal 410 occur when both chromosomes in a pair are black or grey (inside boxes). The inbreeding is on average 12.5 percent.
The size of the pices of identical homozygozety are on average 1/n = 1/3 = 0.33 cM. Where n correspond to three draws of a gamete, in this case two from cup and one from 410.
Animal 401 has exactly half of its chromosomes from cup and half from 400. The animal 410 has on average 75 % of its chromosomes from cup and 25 percent from 400.
Reference:
Christensen, K., Fredholm, M., Winterø, A.K., Jørgensen, J.N. & Andersen, S. 1996. Joint effect of 21 marker loci and effect of realized inbreeding on growth in pigs. Animal Science 62, 541-546.