2006 Annual Report
Dickinson Research Extension Center
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Dickinson, ND 58601
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Proceedings, Western Section, American Society of Animal Science
Vol. 57, 2006
of Weaning Date and Retained Ownership on Cattle Performance and
Forage Disappearance in Spring Calving Beef Systems
D. G. Landblom1,
ABSTRACT: Weaning calves early from spring calving cows can have multiple impacts on beef systems. The objective of this two-year three-state study was to evaluate the effects of mid-August (AW) versus early-November weaning (NW) on cow and calf production traits, forage utilization, and economic return. Five hundred-five cow-calf pairs from the NDSU-Dickinson Research Extension Center (DREC; n=176), SDSU-Antelope Research Station (ANT; n=136) and the University of Wyoming Beef Unit (UW; n=193) were stratified by BW and body condition score (BCS) and assigned to either AW (August Wean - weaned at approx. 140 d of age) or NW (November Wean - weaned at approx. 215 d of age). Cows grazed native range between the two weaning dates. At AW date, a subset of cows from each treatment at DREC were randomly assigned to six 20-ha. pastures (n=3/treatment) to measure biomass disappearance between AW and NW dates. Steer calves at ANT and DREC were weaned and backgrounded 7.4 wk and finished in a commercial feed yard. Steers at UW were backgrounded 42 d and finished on site. Treatment by location interactions were detected for cow BW change, BCS change, calf ADG, and gain:feed. At each location, AW cows lost less weight (P<0.01) than NW cows. Similarly, cow BCS change was improved (P<0.01) for AW vs. NW at DREC (0.91 and -0.55), and ANT (0.34 and -0.02). At UW BCS change did not differ (0.22 and 0.47). Forage biomass disappearance, between weaning dates, was reduced by 27.7% (P=0.15) when calves were AW. AW steers at DREC had higher (P<0.01) ADG during backgrounding than NW; AW steers at DREC and ANT were more feed efficient (P<.01). During finishing, AW steers grew slower (P<.01), but were more efficient (P<.01). On average, at all locations, NW steers entered the feedlot heavier (P<0.01) and required less days (P<0.01) on feed to harvest; however, AW steers were 46 days younger at harvest. Weaning regime lowered feedlot cost/calf and regression analysis of carcass characteristics and weaning treatment suggests a positive effect on annualized rate of return. Weaning spring-born calves early reduced forage utilization, improved cow BW and BCS, improved backgrounding performance and finishing FE, reduced the number of days from birth to harvest, yielded similar finishing performance, and increased annualized rate of return.
Key Words: Early Weaning, Cow Performance, Forage Disappearance, Annualized Return
Profit margins in cow/calf production
are slim due to high production costs (Taylor and Field, 1995) and lost
opportunity to capture value from marketable ranch products (NASS, 1999). Development of systems that lower production
costs while adding value to calves would be beneficial to sustaining and
improving rural communities in the drier regions of the
Body condition of cows at time of calving has been shown to influence subsequent pregnancy rates (Richards et al., 1986), and the body condition score of spring calving cows grazing winter range is influenced by body condition score in the fall (Adams et al., 1987). Lamb et al. (1997) showed spring calving cows grazing native range lost 0.4 of a body condition score if nursing a calf from September to November, whereas cows that had their calves weaned in September maintained condition from September to November. Management of body condition score by weaning early can improve subsequent reproduction and/or reduce the requirements for non-grazed feed inputs that would be required for thin cows.
The Beef Cattle NRC (1996) predicts a spring calving cow lactating in August will have a 9% greater daily intake of range forage than a dry cow. Weaning calves early may allow standing forage to be spared, reducing late season supplemental feed requirements.
Performance of early-weaned calves during the backgrounding and finishing phase is important. Research has shown calves weaned at 100 to 150 days of age were heavier and younger at slaughter than normal weaned (weaned at 225-250 days) calves (Peterson et al., 1987). Meyers et al. (1999) reported that 40% more early weaned steers graded average choice or higher than their normal weaned counterparts. Carcass quality improvement in early weaned calves managed for maximum economic yield parallels value-based marketing trends (Cattle-Fax, 2003).
The objective of this multi-state investigation is to evaluate the impact of early weaning and retained ownership decisions on the relationship between weaning date and herbage availability, cattle performance, and economic returns.
Materials and Methods
Over a two-year period, cow herds from
Calf weaning weights were recorded at
each location. The steer calves from Antelope Station (Yr. 1) and Dickinson
were transported immediately after weaning to the
Following the 7.4 week backgrounding
phase, Antelope and
Steers and heifers at the UW were
managed in a similar manner, but backgrounded at the UW,
Grazing, backgrounding, and finishing
performance were analyzed by ANOVA using a PROC GLM of SAS (SAS Inst. Inc.,
Vegetation samples were collected
Clipped forage samples were obtained in the six pastures just prior to the AW date and again at the end of grazing when all cows were removed from the pastures in November. Samples (0.25 m2) were cut to ground level, using battery-powered electric shears. Samples were oven dried. Forage disappearance was calculated as the difference between pre- and post-grazing estimates.
Analysis of variance was used to evaluate weaning treatment effect on biomass disappearance.
Results and Discussion
In this multi-state weaning date
study, early weaning improved cow body weight (P<0.01) and ending body condition score (P<0.01) at each location (Table 1). Body condition score change from AW to NW was
improved (P < 0.01) for Antelope and
The AW system utilized 72% of the available biomass when compared to the NW system. Forage disappearance for cows that had calves weaned early was estimated to be 803 kg per ha, whereas forage disappearance among cows that continued to nurse their calves for an additional 75 days was estimated to be 1109 kg per ha (P = 0.15). The difference in forage utilization was attributed to calf removal and less trampling.
for NW steers at Antelope and
performance for Antelope,
performance for the two management systems is shown in Table 3. Normally weaned
steers were an average 87 kg heavier on arrival (P<0.01) for all locations and were heavier at harvest for the
weight did not differ for Antelope and UW steers, however, Dickinson NW steer
carcasses were heavier (P <0.01).
Rib-eye area was greater for
August weaned steers had a higher level of production efficiency and lower average cost of production, but AW steers, on average, had a lower return on investment. Regression analysis; however, suggests that, when other finishing variables are held constant, early weaning increases annualized net return by 29% (P = 0.01) (R2 = 0.68).
These data suggest that weaning spring-born calves 75 days early (140 versus 215 days) can reduce late summer native forage utilization, improve cow body condition, improve calf backgrounding performance, and improve annualized net return.
Adams, D. C., R. T. Clark, S. A. Coady, J. B. Lamb, and M. K. Nielsen. 1994. Extended
grazing systems for improving
economic returns from
Adams, D. C., R. E. Short, and B. W. Knapp. 1987. Body size and body condition effects on performance and behavior of grazing beef cows. Nutr. Rep. Int. 35:269-277.
Developing a profitable marketing plan in today’s marketplace. NCBA Cattlemen’s College,
Lamb, J. B., D. C. Adam, T. J. Klopfenstein,
W. W. Stroup, and G. P. Lardy.
Meyers, S. E., D. B. Faulkner, F. A. Ireland, L. L. Berger, and D. F. Parrett. 1999. Production systems comparing early weaning to normal weaning with or without creep feeding for beef steers. J. Anim. Sci. 77:300-310.
National Agriculture Statistics Sevice. 1999. 1997 Census of Agriculture. USDA-NASS. Volume 1, Geographic Area Series, 1A, 1B, 1C, CD-ROM set.
1996. Nutrient Requirements
of Beef Cattle.
Peterson, G. A., T. B. Turner, K. M. Irvin, M. E. Davis, H. W. Newland and W. R. Harvey. 1987. Cow and calf performance and economic considerations of early weaning of fall-born beef calves. J. Anim. Sci. 64:15-22.
Richards, M. W., J. C. Spitzer, and M. B. Warner. 1986. Effect of varying levels of postpartum nutrition and body condition at calving on subsequent reproductive performance in beef cattle. J. Anim. Sci. 62:300-306.
Taylor, R. E., and T. G.
Field. 1995. Achieving cow/calf profitability through
low-cost production. Proc. The Range
Beef Cow Symposium XIV.
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