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Wisconsin Dairy Herd Improvement Association, et al. / Wisconsin D.H.I.A. record
Vol. IV (1937)

Method of using production records,   p. 4 PDF (233.7 KB)


Page 4


METHOD OF USING PRODUCTION RECORDS
Information published in this bulletin is based on lactation records
reported by the D.H.I.A. Fieldmen. The number of milkings per day,
the length of lactation, the age at calving to the nearest month, the
length of the preceding dry period, and any abnormal conditions
which might affect production are reported for each record. Checking
of the accuracy of this information is confined to periodic field inspec-
tion of the fieldman's work, and to mistakes detected in his reports.
The age, days in milk, and average per cent butterfat are checked by
the Records Office.
Registered animals are reported under their registry name and
number, and the sire, dam, and date of birth are checked with the breed
herd registry books before being accepted and filed by the Records
Office. Unregistered animals are reported under their official Wis-
consin (T.B. or Bang's Test) ear tag number. It will soon be pos-
sible to check the date of birth, sire, and dam of unregistered animals
in tested herds with the Ear Tag Identification File in the Division of
D.H.I.A. Investigations, Bureau of Dairy Industry, U. S. D. A.
All production records are calculated, where necessary, to a two
milkings per day, 305 day complete lactation, mature cow basis. The
average of all normal records is used as the production of any indi-
vidual cow. This makes it possible to compare different cows, or
daughters with their dams, under more nearly the same conditions of
test.
Incomplete lactation records adjusted to a 305 day basis are used
whenever the cow has no other complete lactation record. In cases
where several daughters of a sire are sold for low production before
completing a lactation period, this policy helps in obtaining an un-
selected sample of each sire's daughters.
Averaging several records for each cow tends to remove the ef-
fect of any particularly poor or particularly good feed years. How-
ever, in many cases of young cows or of sires "proved" in the last
two years, the effects of the 1934 and 1936 droughts have lowered the
production level considerably. As yet, no satisfactory practical method
of adjusting for the feed conditions under wkch the record uns made
is mailable.
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