A cattle breed close to 58 diploid number due to high frequency of rob(1;29).

Barrosa cattle, reared in the north of Portugal primarily for meat production, number about 40,000 (about 6% of all cattle in Portugal). Their fertility (number of calves per 100 cows) varies from 60% to 80% and is lower than that of other Portuguese cattle breeds. 195 animals (28 males and 167 females), randomly selected from a large area, were sampled for cytogenetical investigation. The results were the following: (a) 68 (34.9%) animals (7 males and 61 females) had normal karyotypes; (b) 127 (65.1%) were found to be carriers of rob(1; 29), as shown by G- and R-banding; (c) 102 (52.3%) animals (17 (8.7%) males and 85 (43.6%) females) were heterozygous carriers; (d) 25 (12.8%) animals (4 (2%) males and 21 (10.8%) females) were homozygous carriers. C-banding patterns revealed one block of constitutive heterochromatin (HC) in the proximal q-arm region of the translocated chromosome.