Thirty newborn Holstein calves born in winter (n = 13) or in Summer (n = 17) were used to evaluate effects of maternal blood injections on diarrhoea occurrence and weight growth (BWG) during one month after calving. Holstein calves were randomly divided into control (C; n = 10; 5 males and 5 females) and treated groups T; n = 20: 10 males and 10 females) 2 hours after birth. Treated calves received subcutaneously 20 nil of freshly drawn maternal blood during the 1(st), 4(th) and 7(th) days whereas control calves received no treatment. Health status and particularly diarrhoea occurrence was checked daily and body weights were recorded at calving and 1 month later. Whereas diarrhoea incidence was not affected by sex or calving season, the maternal haemotherapy tended to decrease it: the diarrhoea frequency fell to 10.0% in the treated group vs. 40.0% in the control group. Moreover mean body weight on day 30 and the daily weight g, in were significantly increased in the treated calves compared to the control;. Contrary to calving season. sex has also significantly affected growth. males exhibiting significant greater performance than females. A significant interaction between haemotherapy and sex was observed: the greater growth !;cores (final body weights and daily weight gains) were obtained in treated mates and in treated females at a lesser extend. These results suggest that maternal haemotherapy may be an easy practice for improving growth performance and infection resistance in newborn calves.