Performance of Canadian Holstein-Friesian cattle in the humid forest zone of Ghana. I. Milk production.

One hundred and three calving records of 35 Canadian Holstein-Friesian cattle introduced in 1974 into Ashanti constituted the data for this study. Age, year, lactation number, season and age X season effects on 305-day yield, lactation length and components of the lactation curve were estimated from 84 complete lactation records. Analysis of variance by General Linear Models Procedure showed significant effect of age and year on all traits studied. Age, year, lactation number, season, concentrate fed and season X age accounted for 61.1, 64.6, 66.9, 68.5 and 38.1% of the variation in 305-day yield, 300-day yield, monthly peak yield, persistency index and lactation length respectively. Age and year significantly affected all traits except lactation length. Lactation number only significantly affected 305-day yield of the traits studied. Season was not an important factor affecting any of the traits. The productive life span of the animals was up to five calvings (eight years). The mean life time milk production was 16,186 kg. Unadjusted means of the 103 records were: 305-day yield 3,878 +/- 93.7 kg; actual 305-yield 4,451 +/- 102.7 kg; total yield 4,225 +/- 160.6 kg; lactation length 332 +/- 14.5 days; days dry 96 +/- 5.9 and total yield per day of calving interval 10.6 +/- 0.33 kg. Performance of Holsteins in Ashanti was better than in most tropical areas.