Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/19/2012
Publication Date: 7/31/2012
Publication URL: http://handle.nal.usda.gov/10113/56273
Citation: Mulliniks, J.T., Sawyer, J.E., Mathis, C.P., Cox, S.H., Petersen, M.K. 2012. Winter protein management during late gestation alters range cow and steer progeny performance. Journal of Animal Science 90:5099-5106. Interpretive Summary: Pregnant cows grazing winter range experience nutritional stress due to climate conditions, a diet with limited nutrients, and nutrient demands due to pregnancy. This study shows that the use of a self-fed supplement utilizing a highly undegradable protein source was as effective as a traditional hand-fed, oilseed-based supplement in maintaining body weight and body condition score during late gestation. The small package supplement was more efficient, with lower cost. This study also showed that calves born from dams provided this self-fed supplement in relatively low quantities, were treated less for sickness and had decreased feedlot costs. This implies that there may be a formulation for range protein supplements, fed during pregnancy, that have a positive effect on calf health and performance. In conclusion, considering the cost of winter protein management and potentially lower calf costs in the feedlot, feeding a small package supplement, high in undegradable protein during late gestation appears to be a good alternative to more conventional methods.
Technical Abstract: A 5-yr study was conducted at Corona Range and Livestock Research Center, Corona, NM to evaluate 3 late gestation supplementation strategies on cow and subsequent steer progeny performance. Late gestation cows received one of three supplementation strategies: (1) 36% CP cottonseed meal base supplement (CSM; positive control) fed 3x/week, (2) self-fed supplement (SMP) comprised of 50% animal or plant protein sources (blood meal/feather meal or corn gluten meal), and 50% trace mineral package, or (3) cows fed CSM according to perceived environmental stress (VAR; negative control) by ranch management. Supplementation was strategically initiated and ended approximately 2 wks prior to calving each year. Across all 5 yr supplement consumption averaged 0.63, 0.23, and 0.04 kg·head-1·d-1 for CSM, SMP, and VAR, respectively. After weaning, steers were preconditioned for 45 d and were received and treated as custom fed commercial cattle at a feedlot in mid-November each year. Cow BW and BCS was not influenced (P > 0.14) by prepartum supplementation throughout the study. However, cows managed in the VAR group lost the greatest (P < 0.05) amount of BW and BCS while no differences were measured between CSM and SMP groups. Prepartum supplementation strategies did not influence (P = 0.98) pregnancy rates. Calf weaning, initial feedlot, final BW, and HCW were unaffected (P > 0.71) by dam’s prepartum supplementation. Steers from dams fed CSM and VAR had a greater percentage treated for sickness than SMP steers (P = 0.05), which resulted in a tendency (P = 0.07) for medicine costs to be greater in steers from CSM and VAR cows. The use of a self-fed package supplement was equally effective as use of a traditional hand-fed, oilseed-based supplement in maintaining BW and BCS during late gestation. In addition, these results imply that although nutrition treatment of cows during the prenatal period had no affect on calf growth performance, calves from cows fed SMP had improved feedlot health.