Volume 22 • Issue 01 • 2018
with the objective to maximize grass yield per
hectare. A formula, where the desired REST
period (RP) is entered to ensure adequate grass
regrowth, and which will dictate the duration
of the grazing period (GP) based on number of
grazing camps and the number of cattle herds,
is the following:
GP = RP / [(# camps / # herds) – 1
Overgrazing is not a function of cattle numbers,
but rather of TIME. Too short a recovery
time happens when cattle are moved too fast
through a set of camps and return too soon to
the original camp.
• By observing the left paralumbar fossa (the
groove behind the last rib on the left side of
the bovine), during the early morning, before
cattle lie down to rest and ruminate, is the
stockman’s indication of rumen fill and hence
pasture intake. As soon as this appears to
become hollow in the majority of cattle in
the herd, it is an indication that DMI is not
sufficient on the particular pasture anymore.
The herd should then be mo ved to the next best
camp in terms of pasture quality and quantity
(Personal communication, D. Nischk, 2003).
• Cattle waiting at the gate is a sure sign that
the decision to move them should have been
taken much earlier. The degree of trampling
and number of pioneer species - relative to the
rest of the camp - around gates gives one an
indication of the stockmanship on a particular
farm.
• Take the urine pH - in the morning - of several
cows after cattle have been on a particular
pasture for at least 12 hours. This may be
considered the “normal” for that type of
pasture. Use these values as the baseline to
compare further pH measurements (preferably
from the same sentinel cows) later on in the
grazing period on that camp. A rise in the pH
values will be an indication that more urea
is being excreted through the urine, which
shows that ammonia is no longer efficiently
incorporated into microbial protein. This
phenomenon may also be as a result of over-
intake of N-supplements (winter licks) due to a
shortage of grazing.
• During the dormant season the short duration
grazing also applies – as opposed to the
temptation to keep cattle on a single camp to
deplete it from most grazable DM and only then
move on to the next camp. The former would
allow for a more even DM intake as well as
supplement intake. For every day longer, the
pasture becomes less attractive to the cattle
and expensive supplement intake will increase
the longer they stay.
When to change to a new supplement
• The first frost leads to accelerated lignification
of grass and sudden fall in digestibility. These
will raise the nitrogen as well as carbohydrate
requirement of the rumen microbes –
especially if available standing hay is from
poor soils.
• An increase in the fecal consistency (fecal
condition score) is diagnostic for a lowered
passage rate of ingesta and a lower herbage
digestibility, both caused by insufficient RDP
availability to the rumen microbes. This is
perhaps the most accurate indicator
• Laboratory analyses for total crude protein
(TCP) and acid detergent fiber (ADF; an
indicator of ligno-cellulose) are expensive and
burden logistics at farm level.
• To wait for the body condition to fall is not the
correct approach, as lost fat reserves need to
be replenished after weaning of calves at a cost
during the dormant season. This cost must be
kept as low as possible.
• Fecal analyses for TCP (= N x 6,25) and P have
been shown to be valuable indicators and can
be used to optimize lick intake
Conclusion
The challenge is: How do we maximize herbage
NFC concentration during the growth season
through proper pasture management?
In order of importance: healthy soils, healthy
grass roots and healthy grass foliage will lead to
the most efficient rate of photosynthesis and NFC
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