The productive performance of four Holstein-Gir genetic groups (1/2H, 1/4H, 5/8H, 5/8Hinter se) and the effects of non-genetic factors on production traits was evaluated using a data set of 7,951 test-day samples collected between January 1980 and December 1999 from the Arcoverde Experimental Station in the Brazilian state of Pernambuco (Empresa Pernambucana de Pesquisa Agropecuaria). The statistical model included the fixed effects of calving year (1980 to 1999) and month (January to December), genetic group of the cow, age at months of calving (33 to 190) and days in milk at each test-day. Random effects were sire, cow and residual with test-days treated as repeated records within each cow within each lactation. For the four genetic groups the milk yield (MY) means were 1/2H = 8.61 kg +/- 1.16 kg, 1/4H = 5.34 kg +/- 0.46 kg, 5/8H = 7.42 kg +/- 0.39 kg and 5/8H inter se = 5.76 kg +/- 0.46 kg; the fat yield (FY) means were 1/2H = 0.375 kg +/- 0.052 kg, 1/4H = 0.231 kg +/- 0.026 kg, 5/8H = 0.299 kg +/- 0.025 kg and 5/8H inter se = 0.231 kg +/- 0.026 kg; and the fat percentage (FP) means were 1/2H = 4.45 kg +/- 0.29%, 1/4H = 4.08 kg +/- 0.12%, 5/8H = 3.87 kg +/- 0.10% and 5/8H inter se= 3.89 kg +/- 0.12%. Phenotypic correlations between tests were MY = 0.97, FY = 0.94 and FP = 0.98. The best productive performance was for the 1/2H group, followed by the 5/8H group. The performance of the synthetic group was substantially below the performance of the 5/8H group.
