Nutrition
In addition, beef cows in this study with a BCS of
4 or less took six more days to become pregnant
when compared with a cow with a BCS of 5 or
greater (90 vs. 84 days). The researchers also found
that 84 percent of cows with a BCS of 4 or less were
pregnant within 60 days after calving, compared
with 91 percent of cows with a BCS of 5 or greater.
For thin cows, increasing the level of energy in
the diet after calving will increase the number
of pregnant cows at 60 days after giving birth.
Cows with a BCS of 4 or less will have comparable
pregnancy rates to cows with BCS of 5 or greater
when fed a diet that allows for maintaining or
gaining weight after calving through rebreeding.
In this study, the amount of energy fed
daily was 15.6, 12.6 and 8.9 pounds of total
digestible nutrients (TDN) per head daily for
high-, moderate- and low-feed energy diets,
respectively. The amount of energy fed daily
during flushing was 21.8 pounds of TDN.
Feed Level Influences Percent of Cows
Pregnant Within 60 Days After Calving
Body Condition Score
Postcalving
Average Daily Gain 4 or less 5 or greater
1-2 lb. gain 92 92
none 92 88
Low 1-2 lb. loss 68 85
Low - flushed* 1-2 lb. loss 85 98
84 91
Feed Energy
High
Moderate
Average
*Flushed 14 days prior to breeding then flushed 14 days prior to and 30 days after bull turnout. The flushing diet for
this study was 9 to 13 pounds grain plus free-choice corn silage.
Source: NDSU Extention
Flushing an Alternative
Flushing is a management term for providing
additional high-quality feeds and grains to
cows starting 14 days prior to the start of the
breeding season and continuing throughout
the first 30 days of breeding. Cows that lost
weight after calving but gain weight prior to and
30 | MAY 2019
during breeding will have a higher pregnancy
rate than cows that do not regain weight.
Specifically for thin cows (BCS 4), increasing
the concentration of energy in the diet will
increase milk production at 90 days after calving
and also reduce the days to pregnancy.