Understanding Your Herd's Culling
Introduction
With low milk prices, and
increasing costs of replacement animals, dairy herd culls have become
more critical to the success of any dairy operation. Recent research
has shown that cull rates in Pennsylvania have been as high as 50
percent. High cull rates have also been associated with a higher level
of purchased cattle, which can be a health risk to any dairy operation.
With numerous factors that impact the decision to cull, maintaining and
reviewing accurate culling records are crucial to successful management
of herd’s culling. There are three segments of record keeping that
allow for successful management of culling: reason for culling, stage
of lactation at culling, systematic review of culling records.
Reason for Culling
There are numerous reasons for a cow to leave the herd. She may have
died, been injured, had low production, sold for dairy purposes, high
or chronic mastitis, feet and leg problems, udder problems, disease,
reproduction, or it may not be reported. Most of the time it may be a
combination of reasons that causes the decision to remove a cow from
the herd. It is vital that at least the primary reason for culling an
animal is reported. Between 2003 and 2005 the top culling reason in PA
was injury/ other, and the accuracy of reporting of culls may have
contributed to this. A cow may be culled for multiple reasons, making
it difficult to determine the actual reason a cow left the herd. The
next highest was reproductive problems, followed by death. By recording
the primary reason a cow leaves, the producer is able to determine if
there is a management area that needs to be addressed to reduce the
impact culling is having on their herd.
Stage of Lactation
Now that the reason (or reasons) for culling a cow have been
determined, her days in milk and lactation upon leaving the herd also
need to be recorded. Problems with dry cows, the transition period, or
other stages of lactation that are impacting culled cows may only be
apparent when reviewing the days in milk when a cow left the herd.
Figure 1 depicts the top three culling reasons for PA over the last few
years by days in milk group. The majority of deaths accorded during the
dry period before a cow began a first or new lactation. The chance of a
reproductive cull increased as a cow reached later stages of lactation.
The chance of injury/ other culls was highest during the middle of the
lactation. If an individual herd has high levels at any given stage, it
may be an indicator that current practices for that stage should be
reviewed. For example, high reproductive culls early in lactation may
indicate poor calving management.
Review of Records
Now that time has been taken to record the reason for culling and stage
of lactation upon exiting the herd, it is vital to review this
information on a regular basis. Trends may not be readily apparent
daily or weekly review, depending on the size of the operation. Herd’s
with high cull rates or concerned about cull rates would benefit from
more regular reviews, such as quarterly or monthly. Even if cull rate
may not be high, a minimum yearly review of culling information should
be performed for any dairy herd.
Conclusions
With increased need for tighter management decisions and higher demand
for quality milking cattle, determining why cows leave individual
operations is crucial. Most reported culls due to death occurred before
a cow’s lactation actually began. Most reproductive culls increased as
days in milk increased. Knowing why and when heifers and cows are
leaving the herd, and being able to manage those reasons, is vital to
the sustained success of any dairy operation.
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Robert C. Goodling, Jr., Extension Educator - Dairy, Penn State Extension, Lebanon/Berks County
