Abstract

LEMES, J.S.; PIMENTEL, M.A.; BRAUNER, C.C.  and  MORAES, J.C.F.. Milk net energy and performance of calves from Aberdeen Angus primiparous cows. Arch. zootec. [online]. 2011, vol.60, n.232, pp.977-983. ISSN 1885-4494.  https://dx.doi.org/10.4321/S0004-05922011000400014.

The availability of net energy in the milk of Aberdeen Angus primiparous cows and his relationship with the calves performance was studied. Fourty seven cows, raised under a range condition, in Aceguá. RS county, were evaluated between September 2005 to April 2006. Milk production (PL) was estimated by before and after suckle method, from birth to weaning (189days), every 21 days. Effects studied were pregnancy (G), and milk production level (NPL): NPLa <1035.70 ± 36.65 kg <NPLb. The following variables were evaluated: calves birth weight (PBN), daily weight gain (GMD) and adjusted weaning weight for 189 days (PBD). There was a tendency to decrease net energy for gain only after 126 days of lactation. The NPLb calves were heavier at weaning and showed higher GMD during all lactation period. Correlation of milk yield and weaning weight was 0.33 showing an increase of 0.025 kg in calves weaning weight for each kg of milk consumed. Milk production answered for 10% of PBD. In range conditions system, milk production supports the calves requirements maintenance until 4 monthsold, even with net energy for weigth gain.

Keywords : Beef cattle; Maintenance requirements.

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