FLORIDA AGRICULTURAL EXPERIMENT STATIONS
Dairy Science Mimeo Report 63,-2I
July 18, 1962
Supplementary Bulky Concentrates for Dairy Cows
J. M. Wing and C. J. Wilcox
Concentrate feed is one of the largest dairy expenses. Florida
dairymen use more concentrates in relation to milk produced than has
been reported from anywhere else in the United States. This is
because often there is an additional offering above the generally
recommended concentrates in the form of a roughage mixture. This
additional feed is likely to contain large amounts of citrus pulp or
other ingredients which though bulky supply relatively large amounts
of productive energy and thus should be considered as concentrates.
Such mixtures usually are very low in digestible protein.
The objectives of this investigation were to measure and evaluate
the response in milk production to bulky concentrates in addition to
the usually recommended amounts of concentrate feeds and a good supply
of leafy roughage.
Ninety lactations were completed by cows assigned to one of three\
treatment groups. (A) Concentrates fed individually according to
recommended standards; (B) Treatment A plus individually fed bulky
concentrates, and (C) Treatment A plus group-fed bulky concentrates.
All animals received the same good to excellent quality forage free-
choice. Composition of the concentrate mixtures is shown in Table 1.
Table 1. ,Composition and cost of concentrate supplements.
Ground snapped corn 36.4 50.0
Citrus pulp 18.2 33.3
Brewers grains 12.2 16.7
Wheat bran 6.1 --
44% soybean oil meal 24.3
Steamed bonemeal 1.0 --
Calcium carbonate 1.0 --
Approximate composition (%)
TDN 69.6 69.9
Digestible protein 14.9 6.8
Fiber 9.6 11.5
Average cost per tona' $51.47 $42.75
a ncludesdelivery but not mixing costs.
Includes delivery but not mixing costs.
All of the animals were observed during a standardization period
when all were fed in the manner described for Group A. The amount
of milk produced during this period was used as a criterion for
assignment to the experimental groups. The experimental groups were
balanced as well as possible in relation to previous records and
performance during the standardization period.
In addition to the milk production during the standardization
period, body weights and days fresh were considered. During the com-
parison period, milk was weighed twice daily and one-day composite
samples taken at 30-day intervals. Monthly body weights were determined
on two successive mornings after milking. Rations were computed at
15-day intervals based on yield and fat content of milk, body weight,
and forage quality, which was rated good or excellent throughout. The
performance of the animals is shown in Table 2.
Animal performance during
standardization and comparison
A B C
Number of cows 26 32 32
Body weight (lb.) 958 978 969
Days fresh 38.9 37.9 40.6
Daily 4% FCM yielda' 88.0 38.2 38.2
Concentrate feeding per cow
Offered daily (lb.) 8.76 9.28 9.03
Consumed daily (lb.-) 8.44 8.51 7,96
Bulky concentrate feeding per cow
Offered daily (lb,) 5.02 4.90
Consumed daily (lb.) 4.91 4.90
Body weight change (lb.)b. +6 +22 +14
Average daily 4% FCM yield (lb.)
Block I (1959-60) 32.2 35.9 34.0
Block II (1959-60) 29.8 29.3 28.8
Block III (1960-61) 37.1 35.7 35.8
Block IV (1960-61) 33.9 36.1 32.6
Averagec' 33.3 34.2 32.8
a. Milk yield during 15-day standardization period.
b. Weight at end of comparison period minus standardization weight.
c. Unweighted .for differences in numbers among blocks.
Daily consumption rates of regular and bulky concentrates, respec-
tively, averaged (A) 8.44 and 0 lb., (B) 8.51 and 4.91 lb., (C) 7.96
and 4.91 lb. Forage intake was not measured. Average daily 4% fat
corrected milk yields were (A) 33.3 lb., (B) 34.2 lb., and (C) 32.8 lb.
These differences were not significant statistically.
It should be remembered that high quality forage was available to
all cows free-choice. Treatment responses might have been different
under conditions of limited and/or poor quality forage or roughage
mixtures. These data indicate, however, that cattle can consume a
larger portion of their nutrient requirements in the form of roughage
than has been estimated by many Florida dairymen. Thus it seems that
the succulent nature of our forage does not limit -its usefulness since
very large amounts can be consumed. This has been confirmed by an
additional experiment which will be published soon. Since rather
unusual rations were being used, it seemed desirable also to test for
other milk constituents as shown in Table 3.
Table 3. Average milk composition during comparison period
Characteristic A B C
Fat 4.94 4.90 5.06
Solids-not-fat 9.48 9.41 9.49
Protein 3.41 3.42 3.48
Chloride .140 .142 .138
Titratable acidity .145 .142 .141
a. Treatment differences not significant for any characteristic.
The observations included assay for fat, solids-not-fat, protein,
chloride, and titratable acidity. The results indicate that milk of
a high quality was produced by all groups. No significant differences
occurred among groups.