The objective of this study was to determine the effects of gender and calf raising program on daily gains during the rearing period, the body weights of six-month-old calves, blood biochemical and hematological indicators and correlations between those parameters. The experiment materials comprised 87 crossbred Polish Holstein-Friesian x Limousin (PHF x LM) calves. 1 group of calves was fed milk replacer via an automated system, and 2group of calves stayed with suckling cows, which were PHF cows. At the completion of the milk and milk replacer feeding period, bulls, steers and heifers reached body weight of 130, 125 and 120kg, respectively. At the pre-weaning calves kept with suckling cows were characterized by significantly (P≤0.01) higher daily gains (0.830 vs. 0.718kg/day). At the post-weaning significantly (P≤0.05) higher daily gains were calves fed milk replacer (0.933 vs. 0.836kg/day). At six months of age, the body weight of calves suckled by suckling cows and fed milk replacer reached 188.9 and 182.3kg, respectively, and their respective average daily gains were 0.835 and 0.798kg/day. Red blood cell, white blood counts and blood glucose concentrations were significantly (P≤0.01) positively correlated with the body weight of six-month-old calves and daily gains (r=0.421 to 0.683). A negative correlation was found between liver function indicators (ALT, AST, ALP) and the growth rate. It can be concluded that the daily gains of calves were affected by the feeding system and the final body weights of calves and their daily gains during the rearing period were affected by calf gender. Higher daily gains and final body weight gained bulls and calves suckled by suckling cows.

Key words: Blood parameters, Correlations, Crossbred calves, Daily gains, Feeding system, Gender