Suckling and allosuckling in river buffalo calves and its relation with weight gain

The aim of the present study was to investigate if river buffalo calves (Bu balus bubalis) have equal access to all cows and if milk is thus equally av ailable to all of them. We recorded suckling/allosuckling behaviour and wei ght gain (WG) of 29 calves (14 males and 15 females), with special consider ation to their sex, birth order (BO) and age. Cows' nursing behaviour and m illi production (MP) were also considered. While males tended to be born ea rlier than females during this study, this was not the trend in the overall herd records. The cows' MP was not effected by the calves' sex. However, b ull-calves presented greater mean WG, and mean times spent in individual fi lial (IF) and in communal nonfilial (CNF) suckling than heifer-calves, whic h showed greater communal filial (CF) suckling than the former during the f irst 4 months of life. The WG was associated with IF for bull-calves (r = 0 .680 and 0.765, respectively, for the periods from birth to 4th and 8th mon ths of age), and to CNF for heifer-calves (r = 0.628, for the period from b irth to 8th month). Results from multiple regression analysis showed indepe ndent effects of each suckling category on the calf WG, and such effects we re variable according to the calf's sex. BO was negatively correlated to ca lves' WG (bull-calves: r(s) = - 0.873 and - 0.799, from birth to 4th and gt h months, respectively; heifer-calves: r(s) = - 0.531 from birth to 4th mon th). Specifically for bull-calves, there was a positive correlation between BO and MP (r(s) = 0.528 and 0.633, from birth to 4th and 8th months of age , respectively). The correlation between BO and IF was negative in both sex es, indicating that calves that were born early had more opportunities to s uckle individually from their mothers. For heifer-calves, BO was positively correlated with CF (two periods), and negatively with CNF (from birth to 8 th month of age), suggesting that heifer-calves were most often accompanied by other calves during suckling when they were born later. The data taken together indicate that sex and/or BO influenced decisively social interacti ons during suckling, promoting differential development among the calves. I n animal husbandry, if a homogenous WG is desired, these factors have to be taken into consideration. (C) 2000 Elsevier Science B.V. All rights reserv ed.