* Strategically Feeding Protein and Energy During Winter and Managing Cow Condition Don C. Adams

Nutrient Requirements of the Cow

Net Energy (NE) Requirements for a 1200 lb March Calving Cow with 23 lbs/day Peak Milk Production NRC (1996)

Crude Protein in Cattle Diets on Sandhills Range Crude Protein, % OM APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB Month

Organic Matter Intake g/kg BW Particulate Passage %/hr Forage Organic Matter Intake and Particulate Passage Observed Using Steers Grazing Sandhills Meadow or Range

Rumen Volume and Dry Matter Fill of Steers Grazing Sandhills Meadow and Range g/kg BW

. Amount of Milk Produced by the Cow

Daily milk production, lb Aug 1 Sept 14 May 28 Adams et al High Low Milk Production by Cows With High and Low Production During Summer Grazing June 18

(1 ) (0.5) Body condition score change June 19 Beginning breeding Sept 20 Weaning Low High Body Condition Score Change for Cows With High or Low Milk Production During Summer Grazing Aug 5 End breeding April 10 On grass

Crude Protein in Cattle Diets on Northern Great Plains Rangeland CRUDE PROTEIN, % 0 APRMAYJUNJULAUGSEPOCTNOVDECJAN

Date of Weaning

Weaning Dates 8 weaning dates: –August 18, 1999 to November 24, 1999 –August 16, 2000 to November 22, 2000 (140 to 240 days after calving)

Effect of Weaning Date on Change in Cow Body Condition Score R 2 =.95

Average Weaning and Supplement Effects on Cow Body Condition Score From September to December Condition Score Change

August weaning 1. No protein supplement during winter grazing 2. Protein supplement during winter grazing Weaning and Supplement Treatments for March Calving Cows November weaning 1. No protein supplement during winter grazing 2. Protein supplement during winter grazing

Effect of Weaning Date on Cow Body Condition Score P<.0001 Pregnancy 95.1% 94.2%

Effect of Protein Supplementation on Cow Body Condition Score P<.0001 Pregnancy 93.8% 95.5%

Wean November Wean No Protein Supplement August Wean August Wean Protein Supplement

November Wean, with Winter Supplement November Wean, No Winter Supplement November Wean, with Winter Supplement

August November Calf Weaning Weight, lb

Protein No Protein Calf Weaning Weight, lb

Costs for Items That Differ and Net Revenues at Weaning August November Supp. No Supp. Supp. No Supp. Cow costs, $/hd Fall grazing Total Cost Supplement

Costs for Items That Differ and Net Revenues at Weaning August November Supp. No Supp. Supp. No Supp. Cow costs, $/hd Fall grazing Total Cost Gn/loss, culls Supplement Revenue, $/hd Calves Net/cow exp

Feedlot Performance Weaning Protein Supp. Early Late Supp. No Supp. In wt, lb Days on feed Interactions ES ENS LS LNS Out wt, lb Daily gain, lb HCW, lb

Costs and Net Revenues After Finishing August Wean November Wean Supp. No Supp. Supp. No Supp. Costs, $/hd Calf Feed Yardage Trucking Processing Total Cost Revenue, $/hd Steer Net/cow exp

Wintering June Calving Cows and June Born Calves

Cost of Winter Grazing (Jan – Mar) and Supplement for June Calving Cows Dry-NSDry-SMilk-S Forage Anim-Unit Cost $/AUM15.00 Total cost, $ Supplement Cost, $/lb 0.09 Cost, $108/d Total costs, $

End of Summer Costs and Breakevens for Calves Wintered in Drylot or On Range Drylot 1999 Range 1999 Drylot 2000 Range 2000 Costs, $ Opportunity Winter feed Yardage Summer grass Total costs, $ Breakevens

Finishing Costs and Breakevens for Calves Wintered in Drylot or On Range Drylot 1999 Range 1999 Drylot 2000 Range 2000 Costs, $ Feed Yardage Total finish Total all costs Breakevens, $

Wintering Pregnant Heifers

Crude (CP), Escape (UIP) and Degradable Protein (DIP) in Cattle Diets on Sandhills Range Protein, %OM APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB Month

Composition of Supplements Fed to Heifers Grazing Nebraska Sandhills Range

Pregnancy Rate of Heifers Supplemented to Meet MP Requirements or CP Requirements

Cost of Supplements Fed and Net Present Value (NPV) of Bred Heifers