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Supplementing cows and heifers on pasture
Dairy Pipeline: August/September 2005
Robert E. James
Extension Dairy Scientist,
(540) 231-4770 email: firstname.lastname@example.org
This year pasture for grazing has been extremely
variable. May was very cool, followed by a very dry
June. In some regions of the state the drought has
persisted, while in others heavy rains have encouraged
lush growth. These variable conditions make a "one size
fits all recommendation" for pasture supplementation an
untenable option for meeting the nutritional needs of
growing heifers. Here are five recommendations for the
pasture reared dairy heifer.
- It's not uncommon for grazers in more temperate
climates to move heifer calves into pasture systems
when they are 3 months old. There are two risks
that must be considered.
First, heifers should be included in parasite control
programs shortly after entering the pasture systems
with the advice of your veterinarian. The second risk
is of low intake and variable quality. Typically
intake is lower on pasture than confinement system
rations. This is especially important when demand
for nutrients is high. Typically young calves (< 6
months of age) will require continued, significant
concentrate intake (5 lb./ head/ day).
- Inclusion of an ionophore will probably yield as
much return as any additive available today.
Ionophores are best included in the diet by including
them in even a limited amount of a concentrate
mixture. Lasalocid (Bovatec) may be fed in free
choice mineral supplements, but Monensin
(Rumensin) is most successful when included as a
component of a concentrate mixture that is fed daily.
- Nutrient levels of pasture are highly variable in
much of the U.S. During the cooler months of the
year it's not uncommon for pastures to contain in
excess of 16% protein and 70% TDN, which is more
than adequate to support excellent rates of growth
(>1.8 lb. / day) in older heifers without too much
additional supplementation. Vitamins and most
minerals are also adequate in high quality pasture.
However, during drought and the hotter months of
the summer, protein may decline to less than 12% and energy to less than 60% TDN, which is not
adequate. During these months supplemental
concentrate feeding is necessary.
- How much concentrate to feed/day? I hear many
dairy producers and heifer growers' state that they
feed 5 lb. / heifer / day regardless of the pasture
quality or availability. If one assumes that a 16%
protein mixture cost $175/ton, this could represent
an extra $.40/head/day in unnecessary added costs if
heifers are consuming a high quality pasture
- Most progressive dairy producers or heifer growers
have weight tapes or have purchased electronic or
mechanical scales to evaluate heifer growth during
routine handling procedures such as vaccination,
parasite control or breeding. This provides an
opportunity to objectively evaluate growth of heifers
and make more timely adjustments in supplemental
concentrate feeding if growth is outside of the
desired ranges of gain. Documented weights can
reveal the existence of management or nutritional
deficiencies that might go unnoticed if the manager
relies solely on the "eyeball method".
Virginia Cooperative Extension