Effects of pre- and postpartum supplementation on lactational and reproductive performance of grazing Nellore beef cows

Context Few studies have evaluated the effects of providing concentrate pre- or postpartum, or during both of these intervals, to beef cows grazing tropical pastures, even though this information is important for planning breeder herd management. Aims A study was undertaken to examine the effects of supplementation with concentrates before calving (prepartum), after calving (postpartum) or during both these intervals on production and reproductive efficiency in Bos indicus beef cows grazing Urochloa decumbens pasture. Methods Nellore cows, initially 6 months pregnant (mean ± s.e.), weighing 516 ± 1.3 kg and body condition score 4.7 ± 0.15 (1–9 scale), were used in an experiment with four treatments in a 2 × 2 factorial design with 20 animals per treatment. The treatments comprised no supplementation or provision of a supplement (1 kg/cow.day containing 28% crude protein) for 90 days prepartum only, 90 days postpartum only or during the pre- and postpartum intervals. Key results Responses could be described in terms of the main effects of providing the supplement pre- or post-calving; the interactions were not significant (P > 0.05). Prepartum supplements increased the cow bodyweight at calving by 29 kg, and calf birthweight by 3.7 kg (P 4 did not change the response to postpartum supplementation. Implications Prepartum supplementation may increase cow performance and calf weight at birth, whereas postpartum supplementation may improve the reproductive efficiency.