Size of foetuses and placentae from primiparous, 15-month-old, angus heifers fed for moderate or low liveweight gain for 21 days prior to insemination and for the first trimester of pregnancy

Two experiments were carried out in which 15-month-old Angus heifers were allocated to a moderate or low liveweight gain treatment from 21 days prior to insemination until day 90 or 91 of gestation. Liveweight gains were 451 ± 32 g/day (n = 8) and 118 ± 32 g/day (n = 8) in the frst experiment and 595 ± 30 g/day (n = 9) and 7 ± 23 g/day (n = 15) in the second experiment. Fetal weight at day 90 or 91 was not affected by treatment. Weight of foetus per 100 kg maternal lifNew Zealands greater in the low compared with the moderate treatments (59 ± 2 and 53 ± 2 g/100 kg versus 47 ± 2 and 45 ± 2 g/100 kg for the first and second experiments, respectively; P < 0.05). Number and weight of cotyledons and caruncles were not different between treatments. Weight gain of 15-month-old Angus heifers had little effect on foetal or placental size.