Measures of daily weight gain in Friesian-Bunaji crossbred heifers and their relationship with first lactation milk yield

This study was conducted to ascertain the relationship between Birth weight, Average Daily Gain (ADG) at 3, 6, 9 and 12 month of age and their first lactation milk yield in Friesian Friesian-Bunaji crossbred heifers. The effects of non-genetic factors such as season, parity and year of calving on the measured characteristics were also investigated. The average daily gains were computed from the monthly weight data. Other variable collected was milk production at first lactation. A total of 585 lactation records were used for the analysis. The average birth weight, ADG at 3, 6, 9 and 12 months and first lactation milk yield (FLMYD) were 26+0.4 kg, 0.39±0.03 kg, 0.43±0.05 kg, 0.4±0.4 kg and 945 kg. Average daily gains were significantly (p< 0.05) affected by season of the year and the effect of calving year was highly significant (p< 0.01). FLMYD was significantly affected by season (p< 0.05) and calving year (p< 0.01). There were positive genetic correlations between growth at 3, 6, 9 and 12 month and FLMYD. The environmental and phenotypic correlations between them were also positive. The heritability estimate was 0.21±0.09, 0.17±0.06, 0.17±0.08 and 0.13±0.01, for ADG at 3, 6, 9 and 12 months, respectively. The results of this study demonstrate that heifers with high genetic growth potentials would reach puberty earlier and would likely be bred and calve at an earlier age with high milk yielding ability.