PERFORMANCE OF EARLY WEANED (APPROX =80 D) VS NORMAL WEANED (APPROX =215 DAY) CALVES IN THE NORTHERN GREAT PLAINS

Authors: Waterman, Richard; Geary, Thomas; PATERSON, J - MSU BOZEMAN; ANSOTEGUI, R - MSU BOZEMAN; LIPSEY, R - AM. SIMMENTAL ASSOCIATION

Submitted to: Western Section of Animal Science Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 5/15/2006
Publication Date: 6/15/2006
Citation: Waterman, R.C., Geary, T.W., Paterson, J.A., Ansotegui, R.P., Lipsey, R.J. 2006. Performance of early weaned (approx =80 d) vs normal weaned (approx =215 day) calves in the Northern Great Plains. Western Section of Animal Science Proceedings 57:103-107.

Interpretive Summary: Early weaning, in spring calving production systems, has intrigued many producers to consider this alternative management practice especially during extended droughts and for young developing cows. The objective of the present study was to evaluate performance of early-weaned calves (EW: ' 80 d of age) and cost of production for two rations that were isonitrogenous and isocaloric but differing in ruminal degradable and undegradable protein (RDP and RUP respectively) compared to normal weaned calves (NW: ' 215 d of age). Thee hundred seventy-three Simmental × Angus calves (108.2 ± 1.07 kg) were randomly allocated to one of three treatments: 1) Weaned and fed a 33:67 forage:concentrate diet containing 15.4 % CP (37 % RUP; EW1); 2) Weaned and fed a 33:67 forage:concentrate diet containing 15.4 % CP (43 % RUP; EW2); or 3) suckled and grazed range forage until normal weaning (NW). Calf weight and age were similar at time of early weaning for all treatments. At the time of normal weaning body weight was heavier for EW vs. NW steers. Similarly, EW heifers were heavier when compared to NW heifers; however, body weights at normal weaning did not differ between EW treatments (P = 0.62). Total cost'calf-1' d -1 was greater for EW treatments than NW; furthermore, calves receiving EW2 had a higher cost'calf-1' d -1 than calves receiving EW1. Value of calves at time of normal weaning were greater for all EW treatments when compared to NW calves ($816.55, $824.82, and $779.71, respectively for EW1, EW2, and NW steers and $714.51, $718.75 and $686.55, respectively for EW1, EW2, and NW heifers), and no differences in value were observed between EW treatments (P > 0.10). This study demonstrates that early weaning may be an effective management option when forage is limited or removal of production pressures for young cows is desired; however, the additional calf value by itself was not enough to overcome cost of early weaning diets.

Technical Abstract: ABSTRACT: Early weaning, in spring calving production systems, has intrigued many producers to consider this alternative management practice especially during extended droughts and for young developing cows. The objective of the present study was to evaluate performance and cost of production of early-weaned calves (' 80 d of age) fed one of two diets (Diets were isonitrogenous and isocaloric but differed in ruminal degradable and undegradable protein (RDP and RUP, respectively)) compared to normal weaned calves (' 215 d of age). Three hundred sixty-seven Simmental × Angus calves (108.2 ± 1.07 kg) were randomly allocated to one of three treatments: 1) Weaned and fed a 33:67 forage:concentrate diet containing 17.5 % CP (31 % RUP) and 1.80 Mcal of NEm/ kg (EW1); 2) Weaned and fed a 33:67 forage:concentrate diet containing 17.5 % CP (43 % RUP) and 1.84 Mcal of NEm/kg (EW2); or 3) suckling and grazing range forage until normal weaning (NW). Calf weight and age were similar at time of early weaning for all treatments (P > 0.10). At the time of normal weaning, BW was heavier (P < 0.01) for EW vs. NW steers and a tendency for EW2 steers to be heavier (P = 0.15) than EW1 steers was observed. Similarly, EW heifers were heavier (P < 0.01) when compared to NW heifers; however, BW at normal weaning did not differ between EW treatments (P = 0.62). Total cost'calf-1' d -1 was greater (P < 0.01) for EW treatments than NW; furthermore, calves receiving EW2 had a higher cost'calf-1'd -1 than calves receiving EW1. Value of calves at time of normal weaning were greater (P < 0.01) for all EW treatments when compared to NW calves ($817.32, $823.24, and $785.51, for EW1, EW2, and NW steers, respectively and $711.96, $717.06 and $686.75, for EW1, EW2, and NW heifers, respectively). Calf value did not differ between EW treatments (P > 0.10). This study demonstrates that early weaning may be an effective management option when forage is limited or removal of production pressures from young cows is desired; however, the additional calf value alone was not enough to overcome cost of EW diets. Key Words: Calf performance, Early weaning, Protein supplementation