RESEARCH BULLETIN
SEPTEMBER,1988
1060
UNIVERSITY or MISSOURI·COLUMBIA
COLLEGE OF AGRICULTURE
AGRICULTURAL EXPERIMENT STATION
ROGER MITCHELL, OffiECTOR
Environmental Physiology and
Shelter Engineering
With Special Reference to Domestic Animals
LXXV.
Productive Adaptability
of Holstein Cows
to Environmental Heat
Part I.
H.D.
Johnson, M. Shanklin and L. Hahn
:1:.
Columbia, Missouri
CONTENTS
ABSTRACT
�
INTRODUCTION
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_
METHODS
MATERIALS AND
__
______________________ _____
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______ ______ __ __
_
�?����
�UL�
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Treatment Effects on Milk Yield, Rectal Temperature
and Water Intake
Energetic Responses of Feed Intake, Milk Yield and
Rectal Temperature . .
.
.
Analysis of Adaptability
.
DISCUSSION
REFERENCES
TABLES, FIGURES, APPENDIX
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4
4
7
8
10
12
16
KEY WORDS: Environment, temperature, adaptability, milk produc­
tion, body temperature, feed intake, heat stress.
The research bulletin was prepared by HD. Johnson, M. Shanklin and
L. Hahn', Department of Dairy Science and Agricultural Engineering,
University of Missouri, Columbia, MO 65211
'Current address: Roman L. Hruska, U.S. Meat Animal Research
Center, Agricultural Research Service, U.S. Department of Agricul­
ture, Clay Center, NE 68933.
2
Abstract
Fifty-one Holstein cows, producing more than 20 kilograms of milk
per day during a three-year study at three stages of lactation, were
exposed to short-term heat (three days at 32 C) to measure adaptive
and productive responses and the time necessary for recovery follow­
ing exposure. Early-stage animals had higher rectal temperatures than
mid- or late-stage animals. Heat exposure reduced milk yields and
feed intake, increased rectal temperature and water intake at all stages.
Four days after being exposed to the heat, milk yields and feed intake
had not recovered whereas rectal temperature and water intake recov­
ered significantly. Nine or 10 days were needed to recover thermoneu­
tral milk levels for early or mid and late stage, respectively. Early-stage
cows had a greater cpnversion ratio of feed to milk (milk/feed, Mcal)
than mid or late stages during thermoneutral conditions and heat
increased this ratio. A review of the frequency distributions for
average individual cow responses to heat (all three stages) for rectal
temperature, milk yield and feed intake suggested the development of
a heat tolerance (positive productive adaptability) and heat sensitivity
(negative productive adaptability) index. These data and the index re­
emphasized the dependency of lactation during heat stress on mainte­
nance of thermoneutral core body temperature and the ability of the
animal to maintain homeothermy and continue adequate feed intake.
Introduction
Heat adaptability of an animal reflects its ability to balance meta­
bolic heat production against environmental heat gains and heat
losses. Consequently, traditional heat tolerance indices have been
based on the stability of body temperature (2, 3, 6, 7, 11, 29, 33). Rectal
temperature is an index of heat adaptability, but it continues to be
controversial for numerous reasons such as differences in response
time to rising ambient temperature due to body size (4, 13). To add
practical significance to a heat adaptability index, a production factor
such as milk yield or growth rate must be equated with the level of
thermal balance or imbalance.
The adaptability of lactating Holstein cows to environmental heat
stress presumably varies with lactation level and individual animal
phenotypic differences. But precise documentation is lacking. Accli­
mation and acclimatization affects (20, 22, 27, 30, 35) productive
adaptability measures (17, 20, 25), and related post-stress recovery
responses are of major importance in assessing the adaptability of an
animal. Productive adaptability is an excellent concept for utilizing the
thermal and productive response to more accurately predict a relative
level of production potential in an adverse hot climate. Thermal
imbalance of the animals negates the production goals of dairy enter-
?
prises, primarily because of economic losses associated withthe e­
cline in feed intake (20), milk production and poor reproductive
performance (27, 35).
Seasonal extremes (15, 34) in all climatic zones of the ��rld. present
environmental limitations to high milk yields. Such 11lruta� lOns are
particularly important during hot conditions in hurni tropical, sub­
tropical and temperate zones which inhibit evaporative heat loss�s.
The overall limitations may be heat and humidity (5, 6), feed quality
and quantity (21, 28), disease and pastures (12), general airy m�nage­
ment practices or a combination of these factors. An Interaction of
several factors may be responsible for suboptimal performance of
lactation (8), reproduction (14, 19, 26) and growt (1, 9, 32). Data
presented in this report are focused on acclimation responses of
relatively high-producing lactating Holstein cattle to short-term (thr�e
day) heat exposure and post-heat response. Heat-i�d,:,�ed effec:ts m
controlled-environment chambers were the sole limiting enVIron­
mental factor with nutritional quality, disease and management fac­
tors being eliminated or minimized as variables. Rectal temperature,
feed intake, water intake, body weight and milk yield measures w�re
used to provide an integrated approach to assessment of productIve
adaptability, which included acclimation trends. A �ubseque�t pub­
lication will describe responses of selected endocrme functions to
assess relative productive adaptability.
.
Specifically objectives of this investigation were to:
-Measure e effects of short-term heat exposure in the laboratory
y-one lac­
on the milk yields, rectal temperature and feed intake on
and to
lactation,
cow's
each
of
tating Holstein cows at three stages
ry and
(prelaborato
preheat
the
to
return
to
necessary
measure the time
preheat) exposure production levels after return to the herd;
-Measure the stage of lactation effects on the above responses for
high-producing cows (22 kg/day); and
.
.
-Estimate the relative individual heat adaptability capacity based
on these measured responses and derived indices.
?
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th
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Materials and Methods
Table I describes the number of cows used, their stage of lactation,
dates and season of entry into the Missouri Climatic Laboratory.
Holstein cows from the University of Missouri herd were the s?urce of
experimental animals. About eye� t ree or fo�r months, SIX cows
were selected for testing using as cnterla a lactat�o� level greater han
22 kg/day at 60 to 100 days post-calving. This Interval pem:'l�t
testing of the cows during all seasons of the year (Table I). After mltlal
selection, the same cows were returned to the laboratory every 90-10
days as representative of mid- and late-lactation cows. As the expert-
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4
3
ment progressed, six early, six mid and six late-stage animals were
tested during each season of the year. A total of nine groups of six
animals were tested at each stage of their lactation. A total of 51
animals were used, including some that calved and were then used.
during a subsequent lactation. The procedure for testing at each stage
of lactation was to record milk yields for nine days at the farm prior to
transfer, to transfer animals by trailer to the Climatic I....:,boratory, and
to start the schedule of measurements after overnight rest in the labo­
ratory. Conditions in the laboratory were controlled as follows: four
days thermoneutral (TN,) conditions, constant 18 C and 60% RH; three
days heat exposure (I-IS), constant 32 C and 50% RH; and four days
post-heat thermoneutral exposure at constant 18 C and 60% RH (TN,).
Following the four days at TN" the animals were returned to the fann
where milk production records were collected for30 days to determine
tinle of post-heat recovery. Daily yields throughout their lactation
were obtained on as many of the cows used as possible in order to
provide an estimate of the persistency of decline. In the laboratory,
daily measures were made on individual feed intake, milk yields and
water intake. Blood samples for honnonal analyses were taken at 10
a.m. and 10 p.m.,and energy metabolism at 1 p.m. daily. Body weights
were measured at 2 p.m. during the adjustment and last day of each
treatment period.
.Em!.
Cows were fed just prior to monling and evening milkings at 6 a.m.
and 6 p.m. Concentrate (UMC ration, HO-23; see Table 2 for compo­
sition and analysis) and long stem alfalfa hay were fed at fixed levels
of 10.0 and 3.6 kg/cow/day, respectively. Com silage was fed ad
libitum daily. Any uneaten concentrate, hay and corn si1age was
weighed and recorded daily to obtain ad libitum intake. Cows were
fed just prior to monling and evening milkings. Crude protein was
measured by the KjeJdahl method and fiber by the acid detergent fiber
procedure, which measures mainly cellulose, lignin, and energy
(expressed as Mcal) by the bomb calorimeter.
&kIl!l Temperature
Rectal temperature for each cow was measured twice daily at 8 a.m.
and 4 p.m. throughout the experiment using 13 cm clinical veterinary
thermometers.
!liaI.I:r Consymptlon
Water was available ad libitum throughout the experiment from
individual animal water bowls. Water meters (Kent, Model PSM 190)
were read at 7 a.m. to measure the total volume of water consumed per
day per cow. Water temperature was about 20 C.
Milking procedure
Animals were milked with a Surge milking system (bucket-type)
twice daily. Sanitary milk procedures included udder wash and use of
strip cups.
Experimental
Resign
Cows entered the study at early, mid and late stages of lactation.
Animals at each of the stages were tested at the various seasons of the
year, to minimize any seasonal bias. �ndividual ani�al sensitivity or
tolerance to the heat stress, recovery tnne and magnitude of response
was also examined. Six animals at midstage of lactation were used as
a partial sham control to assess any treatment, handling or duration of
chamber effects during TN and heat exposure. Responses were sorted
into early, mid and late categories and mean values were obtaIned for
each cow at the three stages. Mean values for each lactational stage and
each thermal exposure (TN" HS, TN,) were tested for significance.
Statistical AnalysIs
Sample mean total milk production and .olher. paran�eters were
compared by stage of lactation and day of tnal,.wlth envlfonmel�tal
treatments imposed as day differences. AnalySIS of va nance, uSll1g
sources of "stage of lactation", "day of test" and interaction was
computed and least square means generated. Sample means were
compared by day and stage to the production of days -9 (farm) and +3
(TN,; as shown in Table 3). This permitted an evaluation.of the effects
of the three-day heat stress (days 4-6) and recovery dunng the post­
heat thermal neutral period (days 7-10).
Results and Discussion
Effectson Milk Yield, Rectal Temperatureand Water
lnJ.IDie.
Figure I describes the average daily milk yield at each �tage of
lactalion for all cows used in the study. The average dally nulk Yield
trend for the nine days preceding transfer to the laboratory was ex­
trapolated linearally as an expected milk yield during the laboratory
and post-laboratory periods.
Milk yields for cows at all stages of lactation declined immed�ately
upon transfer to TN in the laboratory (Figure 1). The decline IS
ascribed to the transp�rt and the new management and environ�ental
conditions associated with stanchion housing, since feed quahty and
type was the same as received at the fann. Milk yield of all groups
declined significantly during the three-day heat exposure With rapid
recovery by day 10 (four days post-heat), although still significantly
less than day 3 TN conditions. Percentage recovenes (day 3 vs day 10)
5
were84%/87�o and 88% {or early, mid and latestages, respectively. The
a��unt of milk lost as a result of the experimental treatments, the
ability of the co,,:s to recover in milk yield and the time for recovery at
each stage of their lactatlOn wer� estimated using the average persis­
�
.
tency dechne (expected milk Yield) shown in Figure I. There was
con�lderable lIldlvldual COw variation in the slope of persistency
de�hne. Cows were sorted into three lactation levels, even though all
ammals entered the experiment as good producers (22 or more kilo­
grams of milk per day) in their early stage of lactation. Animals with
less than 25 kg/day milk yield�had an average persistency decline (M)
of -D.OJ9. Cows with milk yields of 25-30 kg/day had an M value of .031
and higher producers (30 kg/day) had an M valueof-.059. The average
persistency decline was 0.03%/day.
The total milk loss/cow/day due to environmental heat (TN day
+3) compared with "expected" milk yields may be observed graphi­
cally III Figure 1. The dotted line C .... ) in Figure 1 was used to calculate
the heat effect and parallels the calculated persistency line described
prevIOusly. The deviation or losses in milk yield from the farm levels
(farm days-9 to -1l and subsequent persistency (-) line are also shown
III Figure l.
Table 3 provides a daily record of the mean milk yields for all cows
at each stage together with the actual differences from farm (-1) and
TN, (+3) days due to heat treatment. With no corrections for persis­
tency decline, milk Yields recovered so that no significant differences
were detectable between pre·experimenlal production at the farm
(day-l) and post-experimental production at the farm by day 15 for
early, day 22 for mid, and day 15 for late stage cows. Early and mid
stage cows returned to laboratory TN, production levels (day +3) by
day 12 and 13 and by day ·15 for late stage cows. That is four days post­
heat for full recovery by early, six for mid stage cows and seven days
for late stage cows. The stage of lactation and all environmental t-reat­
ment conditions during periodsO, I,2, 3, 4 (Table 4) significantly (P<.05
or better) affected datly milk Yields. The interactions of stage of
lac�atlOn and eT�viront�ent at treatment were also significant.
rable 5 proVides estimates of the total milk yield losses/cow/day
resulting fTom heat and the losses of transportation and adjustment to
laboratory and heat. The total milk losses/cow for the heat effects for
early mid and late stage cows were 20, 38 and 22 kg, respectively, for
:
the mne- to 12-day periods. At $12.50/cwt for milk this would average
about $748 for a l00-cow herd. The total losses in milk yield/cow for
the 14-21 day heat plus transportation effects would average about
$15/cow or $1500 for a 100-cow herd.
To estimate the ability of lactating cows to possibly compensate for
heat-Illduced milk Yield losses subsequent to the heat-stress period
6
(after days 15 or 22, depending on stage ofiactation) to day 40, average
daily milk yields above or below the persistency line were calculated
(fable 6). The net difference did indicate a possible slight recovery of
lost production. But even if the effect is real, the value of the recovered
yield would only be about $53.00 for 100 cows over a 19- to 23-day
period. If milk yields were depressed by heat for more than three days,
conceivably the compensation effects or recovery of milk yield may be
much greater.
A sham trial was conducted in which all conditions of transport,
laboratory management and measurements in the laboratory were
identical to the schedule in Table 1; the only difference was that
temperature during the HS period (days 4-6) was maintained at 18 C,
60% RH. Neither milk yields nor rectal temperature were significantly
different (P<.05) for TN" sham heat or TN, conditions (Figure 2).
Table 7 presents the treatment period mean values for milk yields,
rectal temperature and water intake at each of the three stages of
lactation. Milk yields were significantly (P<.05) depressed for all
lactation stages after transport and exposure to the laboratory condi­
tions (TN,). The heat treatment Significantly decreased yields for all
lactation stages. Recovery of milk yields during TN, to previous TN,
levels did not occur for any stage of lactation. Mean 30 day values
uncorrected for persistency decline for the post-laboratory exposure
(fann) were significantly lower (P<.05) than the prior farm milk yields.
A comparison among the three lactation stages at each of the environ­
mental treatments (Table 7) showed all milk values to be different.
Rectal temperatures were significantly increased by the heat exposure
for cows at all lactation stages, but returned to prior TN, levels during
TN,. Rectal temperatures were slightly, but significantly (P<.05),
higher for early stage cows during heat exposure than mid or late stage
cows. Water intake significantly (P<.05) increased during the heat
exposure, but returned to pre-heat levels (TN,) during the TN, period
for all lactation stages. However, late stage cows were significantly
lower than early or mid lactation cows during TN} condilions.
Table 8 provides mean daily milk yield, rectal temperature and
water intake during the TN" heat and TN, treatments. These values
permit an assessment of the response time after exposure to the 30 C,
50% R H conditions; i.e., the day on which values differ significantly
from day 3 of TN,. Recovery responses to values after the TN, period
begins can also be evaluated. Milk yields decJined significantly (P<.05)
on day 6 (third day of heat exposure) for early stage cows; mid and late­
stage cows declined significantly (P<.05) by day five. Recovery of milk
yields to the TN, (day three) values did not occur by the end of the TN,
period (day 10) for cows at any lactation stage. Rectal temperatures
increased significantly (P<.05) on day 4 (first day of heat) for early and
7
8
day 5 for mid and late-lactation stage cows. For all stages of lactation,
the COws returned to TN, levels on the second day of the TN, period
(day 8).
exposure for all stages and did not retum to TN, levels during the fOUl
days post-heat TN, period. For an unknown reason, the early-stage
lactating cows had a significantly lower intake (27.2 Mcal/day) during
TN, than mid (28.4 Mcal/day) or late-stage cows (29.8 Mcal/day).
There also was significantly less recovery after heat stress by early
lactation stage cows than by mid and late stage cows. However, there
was no difference in feed energy intake among the three lactation stage
cows during heat exposure. Table 11 indicates that stage of lactation
had no effecton rectal temperatures though early vs mid and late stage
was shown earlier to be significant (Table 1). Other measures -- waler,
net energy intake and body weight -- were significantly affected by
environmental heat.
Energetic Responses
Figure 3 illustrates energetic responses for milk and feed (Mcal/
day) together with rectal temperatures (0 during heat exposure and
subsequent post-heat trends compared to pre-heat values for all cows
in early, mid and late-Iactalion stages. Increased body temperatures
during the heat exposure provided a signal for decreased voluntary
feed intake. Feed intake energy declined relatively greater than milk
yield energy during the exposure time. By the third day of heat expo­
sure, relatively fewer Mcal of feed were consumed per Mcal of milk
produced. Rectal temperatures progreSSively increased during this
period. As rectal temperatures declined during the post-heat period,
feed intake energy recovered relatively faster than milk yields, energy
and the milk/feed energy ratios and returned to pre-stress values
during TN2 treatment. The ratios of milk/feed energy increased pro­
gressively during heat exposure from days four through seven (Table
9), indicating less feed intake per unit of milk yield. A quite consistent
increase in the ratio of milk/feed energy occurred during heat expo­
sure for all lactation stages. The ratio during early lactation was 0.58
to 0.68, while it was 0.47 to 0.57 during midstage lactation. The ratio
was 0.38 to 0.48 during late-stage lactation. Considering body weight
loss during heat exposure as an energy input for milk synthesis, the
milk/feed plus equivalent body weight energy declined slightly dur­
ing heat exposure and continued to decline until day 8 (second day of
TN2 period). The decline indicated reduced efficiency during this
period of reduced feed intake.
The milk/feed energy ratio declined as lactation progressed from
0.58,0.47 to 0.38 during TN,. During heat exposure the values similarly
decHned through E, M and Lstages, (0.68, 0.57, 0.48) respectively. The
mean declines for TN, were 0.57, 0.42 and 0.36., respectively. These
data generally indicated that more feed was required per unit of milk
as lactation progressed and thus resulted in less efficienl conversion of
feed to milk.
The comparative responses of milk yields, feed intake and rectal
temperatures are illustrated in Figure 3. The relative declines in milk
yield and feed intake were similar for each stage of lactation. However,
the increase in rectal temperature was slightly higher at the early stage
of lactation.
Feed energy intake and body weight as affected by environmental
temperature for each stage of lactation are given in Table 10. Energy
intake expressed as Mcal/day decreased signiJicantly upon heat expo-
Analysis
of
Adaptability
Since these experimental animals were selected at random from a
herd all having a level of production greater than22 kg/day at the early
lactation stage, this experiment afforded an opportunity to assess
relative phenotypic differences in heat lolerance at each stage of
lactation. Milk yield and feed intake data were combined with rectal
temperature in terms of a producLivity index. Criteria used to establish
negative or positive heat adaptability were the milk yield declines, the
magnitude of rectal temperature increase and the decline in feed
intake by day three of heat exposure.
To further understand the individual animal characteristics in ani­
mal productive adaptability in differences of TN, (day three) at each
lactation stage vs heat (day six) measures were calculated for rectal
temperature,milk yield and feed energy intake. These differences for
the three stages for each cow were averaged and distributed ioto cate­
gories (Table 12). Differences in rectal temperature (R) (day three vs
day six) ranged from 0.3 C to 2.8 C. The extre�es of the population
were designated as positive heat adaptable if rectal temperature
changes were less than 1.2 C and those cows wilh 2.4 C or greater as
negative heat adaptable. The designation was based on the average in­
dividual response at all three stages. For comparison, similar distribu­
tions were developed for the productive characteristics of milk yield
(M) and feed energy intake (I'). Because of stage of lactation differences
in volume of milk yield, percentages were used in these comparisons.
The percentage decline in milk yield during heat (day six) ranged from
zero (100% of normal production level for TN, on day three) to 55%
(45% of the TN, level). Individuals producing 92% or more of day lhree
yields were designated as positive heat adaptable and those producing
72% or less designated as negative heat adaptable. Feed energy intake
includes the average intake of concentrate,silage and hay expressed as
Mcal/day. These feed intake data confirm the earlier work of Johnson
9
10
et al. (25) which served as the basis lor relationships developed and
used by Osburn and Hahn (32). Table 12 also showed the derived index
values lor R M (Rectal Temperature increases x Milk Yield % decline)
and for RMF, which includes a decline in feed intake as a multiple
factoT.
01 the 51 total cows, four (4, 91, 857 and 984) met all 01the designated
criteria for the rectal temperature (R), milk production (M) and leed
intake (F) c1assilications. They also met the criteria lor the calculated
R x M or "RM" productive adaptability and the R x (M + F) RMF index
as (+) productive adaptability, Similarly, three cows (75, 44, 925) met
aU 01the criteria lor a negative (-) productive adaptability index.
Six other cows >yhich satisfied the criteria lor (+) RM or RMF but
exceeded the limits lor some 01the classifications (R, M, or F) are also
shown in Table 12. Cows 90, 16, 686 met the (+) classification lor R but
did not meet the M and F (+) classification range. They presumably
declined rnore in milk yield and feed intake to minimize an increase in
rectal lemperat-ure. Two other cows exceeded the rectal temperature
(R) limits but did not decline in milk (M). These examples illustrate the
variation among animals in the relative compromises made for ther­
mostability or maintenance 01 milk yields and leed intake.
At the other extremes 01 this randomly selected group ol cows with
genetic potential to produce greater than 22 kg/day in early stage 01
lactation are heat sensitive and negative animals based on R, M and F
c1assilication and which have negative RM or RMF indices. Included
in this listing are eight animals that only exceeded the 1imils of one clas­
silication (R, M or F). The negative (-) productive indices (RM or RMF)
were marginal lor cows 796,844, 7 and 53, though all cows lar exceeded
the greater than 28% milk decline except cow 7.
Table 12 lists the remainder 01 the cows which were intermediates
in most index c1assilications, with the exceplion 01cow 26. All 01 these
cows were within the derived RMF range 0117.4 to 97.2. Only lour 01
the cows were slightly outside 01 the RM range (9.6 to 67.2).
Regarding the merits of using more than one primary measure or
derived index to select the most or least productively adaptable
animals, it is apparent that lor lour cows only one measure (R, M or F)
would be satislactory, but would eliminate two cows (100 and 989) that
can produce well under heat stress. Conversely, cows 90, 16, and 686
would be selected on the basis ol R but declined somewhat more than
desired for M. The RM or RMF index would retain all 01 these animals
as the top 20% of the cow group. Appendix [lists the body weights of
each cow at each stage 01 lactation. The data may be useful in luture
evaluation of the productive index. Figure 5 shows frequency distri­
butions for the three primary measures, the two derived indices and a
combination of all classifications for cows that fully met all criteria.
herd to extreme
These classifications demonstrate the response of a
rature, milk
tempe
body
in
s
stressors of heat and the relative change
yields and feed intake.
at 18 C and
These curves illustrate the median and range 01 values
rectal tem­
median
the
es
increas
only
not
heat
al
nment
Enviro
C.
32
rectal tem­
01
range
wide
a
was
perature to 40.5 C or greater, but there
all stages,
for
C
32
at
sed
decrea
though
peratures. Milk production,
late-stage
But
ges.
midsta
and
early
lor
teristic
charac
r
showed a simila
A greater
y).
curves were spread over a much wider range (5-30 kg/da
day
Mcal/
18
d
aroun
intake
number 01 early-stage cows showed leed
ge
midsta
at
r
simila
were
Values
C.
18
at
day
at32 C andabout 2 8 Mcal/
30
around
was
intake
leed
ls'
anima
the
01
more
but at the late stage
On.
utl
dlstnb
Mcal/day at TN and 18 Mcal/day at 32 C with a WIder
Discussion
number of �x­
Quantitative data on responses of a relatively large
e and humid­
ralu
tempe
al
�
nmen
enviro
same
the
:
to
cows
perimental
they also
smce
uselul
ity as developed in this study are especIally
Ill. the
lImlled
qUite
are
which
es
chang
include the post-heat recovery
tlme
raturetempe
the
on
ation
infonn
e
provid
literature. These data
.
weIght
body
and
yield
milk
,
intake
leed
,
rature
tempe
eflects of body
rm adapt�tlOn.
changes which are the key lactors in s,�ort or long-te
,
l hty , the
daptab
ctlve-a
produ
Data were lurther analyzed in terms 01
.
ctive state,
ability to maintain the prestress physiological and produ
related
and
n
lactatio
In
gams
g
nsatin
compe
any
of
and measures
s.
lunction
ry did not
Responses to environmental heat and post-heat reco�e
01 early­
ablhty
The
n
lactatio
01
differ greatly as a result 01 stage
:
and to
stress
heat
ing
follOW
yields
milk
r
lactation cows 10 recove
cows.
ctation
late-la
or
formid
than
r
greate
hat
somew
compensate was
de­
days
9-12
d
The average post-heat recovery time reqUIred aroun
longer
A
levels.
TN,
to
pending on stage of lactation when compared
ry tIme period.
stress period presumably would requIre a longer recove
would result
ctton
produ
milk
in
n
nsatio
compe
less
Whether more or
i�take, �ilk
feed
s
reduce
heat
al
nment
Enviro
ture.
conjec
of
is a matter
m growmg
But
cows.
ng
production and the body reserves in lactati
mvolves
only
h
growt
and
intake
animals, depression ol leed energy
can be
whIch
es
reserv
energy
r
and/o
t
the depression of body weigh
lower rallo
a
had
ls
amma
tage
Late-s
(16).
nsated
compe
more readily
of feed/milk energy decline.
.
ctIOn levels,
Though the cows had similar milk potential and produ
dIfferences as
there were considerable individual heat adaptabIlIty
the ablhty to
or
ce
toleran
Heat
eters.
param
s
measured by the variou
111 milk Yields and
maintain thermal balance, especially when changes
11
voluntary feed intake are combined for a "productive adaptability"
index, can provide a scientific basis for the establishment of improved
strains for adverse climatic zones. As long ago as 1932, Edwards
described the problems of adaptability of temperate cattle which were
transferred to tropical climates, but to date no major international
scientific effort to resolve or minimize these problems has been initi­
ated.
Of special significance in this study was the simultaneous measures
of a spectrum of parameters on 51 cows at three stages of their lactation,
with the cows selected at random from a group (herd) having produc­
tion leveis greater than 22 kg/day in the early stage of lactation.
Cenerally, but with some exceptions, animals which had a higher (+)
productive adaptability index declined less in milk and feed intake and
had relatively less increase in rectal temperature. Within the ranges of
milk production, the duration of exposure and temperature stress the
stage of lactation was not a major factor in the milk decline due to heat,
or the post-heat recovery. The primary measures af rectal temperature
(RT), milk production (MP) or feed intake (F) appeared to classify the
animals similarly to the derived indices (RM, RMF) for negative or
positive adaptability. This relationship of rectal temperature to per­
formance (milk yield) describes clearly the functional significance of
thermal balance and energy related or "productive" functions. Coef­
ficients need to be developed with appropriate supportive data for
other livestock to equate a relationship with milk yield. These data do
providea productivity index within a production level range and dem­
onstrated large individual differences in productive adaptability to
heat stress.
A major challenge to the successful utilization of purebred temper­
ate-evolved cattle and their crosses in the humid tropics and subtrop­
ics of the world is to utilize selective breeding practices with the aid of
a productive-adaptability index that recognizes both thennal balance
and production level. Of course, the heritability of the higher produc­
tive-adaptable animals needs to be established. Ultimately, an index
shouId incorporate the relative effects of temperature,feed and disease
resistance on production, as these are important animal adaptability
characteristics (or the various climatic zones of the world.
References
Baccari,F.,jr., H.D. johnson, and C.L. Hahn. 1983. Environmental heat
effects on growth, plasma T, and post-heat compensatory effects on
Holstetn calves. Proc. Soc. Exp. BioI. Med. 173:312-318.
Barrada, M.S. 1957. Responses 01 dairy cattle to hot environments
with special emphasis on respiratory reaclions. Ph.D. thesis. John
Hopkins University, Baltimore, MD.
Benezra, M.V. 1954. A new index for measuring the adaptability of
cattle to tropical conditions. j. Anim. Sci. 13:1015.
Berman, A., and A. Meltzer. 1973. Critical temperatures in lactating
dairy cattle: A new approach to an old problem. Int. j. Biometeor.
17:167.
Berry, I.L., M.D. Shanklin, and H.D. johnson. 1964. Dairy shelter
design based on milk production decline as affected by temperature
and humidity. Trans. Amer. Soc. Agric. Eng. 7:329.
Bianca, W. 1963. Rectal temperature and respiratory rate as indica­
tors of heat tolerance in cattie. j. Agric. Sci. 60:113.
Brown,W.H., M.D. Shanklin,C.L. Hahn,and H.D. johnson. 1969. Rate
of rectal temperature rise as an index of heat sensitivity. Trans.
Amer. Soc. Agr. Eng. 12:225.
Buffington, D.E., A. Collazo-Arocho, C.H. Canton, D. Pitt,W. n",ld-er
and R.j. Collier. 1981. Biack globe-humidity index (BCHI)as comfort
equation for dairy cows. Am. Soc. Agric. Eng. 81: 7U-714.
daSilva, R.C. 1973. Improving tropical beef cattle by simultaneous
selection for weight and heat tolerance. Heritabilities and correla­
tions of the trails. j. Anim. Sci. 37:�37-642.
DeDios, O. 1984. Season and feed supplement effects on lactating
Holsteins in humid tropics of Mexico. Ph.D. Dissertation. Univ. of
Missouri-Columbia.
Dowling, D.P. 1956. An experimental study of heat tolerance of cattle.
Aust. j. Agric. Res. 7:469.
13
Fri5CI� 1 J.E. 1981. Chang �s occurring in cattle as a consequence of
selectIOn for growth rate 111 a stressful environment. }. Agric. Sci.,
Camb. 96:23.
Guidry, A.j., and RE. McDowell. 1966. Tympanic membrane tem­
.
perature for mdlcatm
g rapid changes in body temperature. j. Dairy
ScI. 49:74.
Gwasduskas, F.C, W.W. Thatcher, and Cj. Wilcox. 1973. Physiologi­
cal, environmental and hormonal factors at insemination which
may affect conception. j. Dairy Sci. 56:873.
Hassan, A., N. AI-Akkam and M. Samak. 1982. Effects of various
lactatIOnal effects. Wid. Rev. Anim. Prod. 18:71-79.
Hahn, G.L. 1982. Compensatory perfonnance in livestock: [nOuences
or envIronmental criteria. Proc. of Second IntI. Livestock Sympo­
.
SIum pp 285-294. Publ. SP-03-82, Amer. Soc. Agric. Engrs., St.
Joseph, MI.
Horst, P. 1983. The concept of "productive adaptability" of domestic
ammals III tropIcal and subtropical regions. j. S. Air. Vet. Assoc.
3:159-164.
[gono, M.O. and Y.O. Aliu. 1982. Environmental profile and milk
.
produc �lOn of Frelslan-Zebu crosses in Nigerian Guinea Savanna.
lnt. j. BlOmeteor. 26:115-120.
Ingraham, RH., RW. Stanley, and W.C Wagner. 1979. Seasonal
effects of tropical climate on shaded and non-shaded cows as meas­
ured by recLal temperature, adrenal cortex honnones, thyroid
, production. Am. j. Vet. Res. 40:1792.
honnone and mIlk
John �on, H.D. 1980. Environmental management of cattle to mini­
mIze the stress of climatic change. Intern. J. Biometeor. 24:65-78.
johnson, H.D. 1976. World climate and milk production. Int. j. Biometeor. 20:171-180.
Johnson, H.D., L. Hahn, H.H. Kibler, M.D. Shanklin and H.D. Edmond­
son. 1967. Heat and acclimation influences on lactation of Holstein
cattle. Mo. Agr. Exp. Sta. Res. Bull. 916.
Johnson, H.D. 1965. Environmental temperature and lactation (with
14
special reference to cattle). lnt. J. Biometeor. 9:103.
johnson, H.D., A.C Ragsdale, 1.L. Berry and M.D. Shanklin. 1963.
Temperature-humidity effects, including influence of acclimation
on feed and water consumption of Holstein cattle. Mo. Agr. Exp.
Sta. Res. Bull. 846, November, p 10.
Johnson, H.D., A.C Ragsdale, 1.L. Berry and M.D. Shanklin. 1962.
Effect of various temperature-humidity combinations on milk pro­
duction of Holstein cattle. Mo Agr. Exp. Sta. Res. Bull. 791.
Madan, M.L. and H. D. johnson. 1973. Environmental heat effects on
bovine luteinizing honnone. J. Dairy Sci. 56:1420-1423.
Maust, L.E., R.E. McDowell and N.W. Hooven. 1972. Effect of summer
weather on performance of Holstein cows in three stages of lacta­
tion. j. Dairy Sci. 55:1133-1139.
Mawson, W.F. Y. and B.J. White. 1971. Climatic and biological limita­
tions to dairy production in a tropical environment. Trop. Grass­
lands. 5:145-157.
McDowell, RE., D.H.K. Lee, M.I-1. Forhman, J.F. Skyes, and RA.
Anderson. 1955. Rectal temperature and respiratory responses of
jersey and Sindhi-jersey (F,l crossbred females to a standard hot
atmosphere. j. Dairy Sci. 38:1037.
Miescke, Von G., E.I-1. johnson, j.H. Weniger and D. Steinhauf. 1978.
Oer EinfluB von Warmebelastung auf Thermoregulation and Leis­
tung laktierender Kuhe. Z. Tierszuchtg. Zuchtgsbiol. 95:259-268.
Osburn, D.O., and L Hahn. 1968. Economics of environmental control
for livestock. Can. j. Agric. Econ. 16:116.
Payne, W.j.A. andJ. Hancock. 1957. The direct effect of tropical climate
on the performance of European-type cattle. Emp. j. Exp. Agric.
25:321-338.
Rhoads, A.D. 1944. Iberia heat-tolerant test for cattle. Trop. A g r i c .
(Trin.) 21:162.
Roman-Ponce, H., W.W. Thatcher, D.E. Buffington, c.J. Wilcox and
H.I-l. Van I-lorn. 1977. PhYSiological and production responses of
dairy cattle to a shade structure in a subtropical environment. j.
Dairy Sci. 60:424-429.
15
Thatcher, W.W., F.C. Cwazdauskas, C. J. Wilcox, J. Tonis, H.H. Head,
D.E. Buffington, and H.B. Frederickson. 1974. Milking perform­
ance and reproductive efficiency of dairy cows in an environmen­
tally controlled structure. J. Dairy Sci. 57:304.
Table 1. Schedule ror C:OW8, stage of lactatIon lind leason. dates In laborlltory.
Stltge
[)flte
of
Cows
Co,,, Numbers
60S*,
61.8.
'84
880"',
7.
919,
I'
'. ,
686. 608�.
16.
10/,
" . B-HIt,
942'" ,
1l6.
B-33"
90.
100. 91.
93,
l4.
106, 109
W
]IU{19
S
L
9/12/79
F
,
6/20/19
H
LO/02/7Q
F
L
1/02/60
W
10/17/79
F
1116/80
W
.1
" . 880". 999
"
990.
994,
J/l5/79
8-1t.
8-27.
I'
"
925,
".
(6-20)
101
"
L
916,
92,
75.
SUllon:
(I'),
1./30/80
SI'
2/0ft/PoO
W
5/14/80
"
7 nO/BO
,
5/28/80
"
L
11/28/flO
,
12/10/80
H
2/11/81
sr
W
1/28/81
F
W
L
S/ll/Sl
SI'
,
2125/81
W
H
51'17/81
SI'
I.
9/16/81
F
,
6/10/81
S
H
10/07/S1
F
(Sham)
28,
Senson
H
8-1 J
656, 9/.2'" •
6-8, a-19. B-1,
11-26.
L.aboratory
1129
(lIf,4). 989
857.
Entered
1/27/82
'84
"
Spring (SF), Harch 2l-June 19;
Septemher 20-[)ecember 20; Winter
w
'0
2/08/82
11.2
Summer
(1/)
.COIo/II tilled In tlo/O h.borlltory lIertes (608,
(5),
June 20-September 19;
Ilecember 2l-Hnrch 20
880, 1,)), 9/.2)
Fall
Table
2.
Composition o f UMC Ration
110-23
and hay.
and analysis o f grain,
silage.
Pe.104
P
Grain Concentrate Composition
e rcent age
..�
'"
Ingredients:
Ground Corn
78.2
13.4
5.0
Soybean Heal
Molasses
Dicalcium
Urea
1.2
Phosphat e
1.0
1.0
0.4
0.2
0.2
Salt
Phosphorous
to Sulphur
(Dynamate) '
Hsgne9ium
V i t amins A & D
Protein
D.M.%
Grain Concentrate
S i lage
Alfalfa Hay
..
..
.,
..
.,
..
.,
..
r�l 0)
a...
.,
20 . 3
12.4
17 . 3
Anall::9 Js
of
Fiber(ADF)
D.H.%
4.4
30.6
37. I
th.
Feed
E.N.E.
HeaL/kg
1.9
1.4
1.2
-"-
--"'-
21.0 , . n
26.3
11.4
21.1
a . 6 · . ..
2�.2
·
21.5 ·
11.0 ,
22.4 ,
n.? ,
."
21 . 4 ,
•
"
."
IB.l
L6 . 4
"
"
..
"
"
"
"
"
..
"
.-
"
,.
"
"
�,
"
"
"
n
"
"
"
"
"
"
"
"
!J . I
n.J
D.S
·
. 57
. ..
. ,.
2 4 . 1 · . ..
1 4 . ' · . ..
24.6 · . .,
H . I , ...
2 S . 2 • ...
·
�1.9·
_2.)'
-1.9'
-1.4
. , ".
.. ,
. ..
."
1.12
_1.1
-1.0
-0.5
1.21
Ln·
-0.4
L .66'
.. .
.. . ,
·0 . 1
2.21'
2.2'
· . ..
2 ' . 1 , . ..
2 5 . 4 , .,.
-O.B
· ..
· .,
· .,
2).1
·
ZL6 ,
2S.6 , ."
24.8
2'.1
·
."
."
� S . � · . ..
2S.� , . n
� 5 . 0 · . ..
1 5 . 1 , ."
1 4 . 4 , . ..
24.4 , . l 6
2l.4 · ...
2 4 . 1 , ...
2 4 . 9 , .n
13.1 , . ..
2 4 . 1 , . ..
H . I , . ,.
1 4 . 4 · . ..
l 4 . S · . ..
2l.!
. ..
,
\4.3 ,
19.0 · . "
2 0 . 3 , ...
lL.1 ,
. ,.
. .,
u.s
u.s
."
."
1 .48
I . ]'
2.0L"
LH'
I./Z·
..
1.0�·
..
· ..
· .,
·
L.!'
1.6'
..
-I.)
I.n'
,"00
I . 99
-L.l
_1.1
. ..
. ..
-1.5
· ..
·L . S •
l . �l
. ..
., ,
_1.6
. ..
, .00
_1.1
-l.�
\'IL
. ..
-1.8 •
20.0 ,
20.16. . "
20.6 , .»
2 1 . 0 , . ,.
. ..
11.6
1 1 . ' · ."
21. 2 , ."
."
20.'
1 0 . 1 , .. .
1 1 . 4 , ."
1 1 . 2 , ...
ll. L
11.J
,
,
.n
.n
1 1 . 1 , ."
2 1 . 1 , .n
2 1 . 1 , ."
1 1 . 0 , ."
2 1 . 1 , .,.
2 1 . 0 , ."
2 1 . 1 , ...
10.) , . n
1 1 . 1 , . ..
21.Z , ...
�0.4 ,
. �.
·
. ..
."
• . ..
1'.1 • . "
Ll . 6 · . n
L 1 . 1 • .12
11. 5 · ...
L4.1 • ."
.n
.»
. ..
·
u. s
. ..
19.6 · . "
19.5 , . »
20.1 , . ..
111 . 2 , . "
2 0 . 1 , . ..
-"-
1 8 . S , . ..
16.5 • .11
16.1 · ."
16 . 1 • . n
.n
1 6 . 2 · . ..
1 7 .4 · . ..
21 .6 , ...
-"-
U.4 , . ..
18.6 • . n
1 1 . 1 , . ..
. ,.
. ..
·
LATE
O l t r On
I I . S , . ..
1 9 . 2 , . ..
11.1 , . n
1 � .8 , .. .
10 . 4 , . "
. ..
. ..
ID . B · . n
--"'- �
, . ..
1 9 . 2 , . ..
1 9 ... , . "
. ..
L 9 . 9 • . .,
I H .O · j4
�-I:
ottf O.y
-"-
. ..
21.1
ZS. l · . n
.n
h.] ,
n.o ·
�, OJ
!lIn Prod
, ."
16.� · . . .
!6.) · . ..
26.) · . "
2,.1 , ."
26.4 • . ,.
fl...
m
'"
t ULY
o t t f O�l
H.'
1l.4 ·
'"
ChelOical
Corn
�
III!� �.....
·1.4
-1.1'
� 1 .Al·
-2.6'
."
. ..
. ..
-2.9'
."
-J."
-1.1'
. ..
...
-1.0'
-� . 6 '
-2.4'
-1.9'
_\.4
-1.5
-1.8'
-!.I"
-2.8'
-1.5
-L . 1 '
-1.9'
_1.1'
-L . 8 '
_1.1'
· 1 . 1"
-! .9'
_I."
-1.9'
-1.8'
·2 . 1 '
·1.9"
·1 . 8 '
_� . 5 '
. ..
...
'"
L .82'
L . 16'
1.41
. .,
.. .
, .69'
, ..
1.]1
i . 54
1.19
L>
1.}6
'-'
,
,
•
"
1.16
. ..
"
"
. ..
14.S · . n
1 6 .2 • . ..
15.9 · . "
15.9 ·
...
. ..
17.0 ·
L7.4 · . n
1 1 . 2 , . ..
L I . l , ...
L 7 . 2 • . ..
L l . 2 · ."
Ll.9
·
."
II.'
·
...
.. .
11.6 , . ..
11.0 ·
1 6 . ' • . ..
L I . 1 · .n
L 1.6 • . ..
1 1 . 6 , .. .
1 7 . 4 , ."
1 7 . 1 • . ..
�2.4 ·
-2.6'
-1./i'
-J .5
_I. L
-1.1
· ..
-1.1
_L .1
· ..
· ..
·
.H
· . ..
· ."
. ..
. ..
. ..
1.04
. ..
.. .
1 . 24
.n
· ..
1.01
-1.6
_\.4
·
.
.H
-I.)
.
-1.0
-1.1
-1.2
.n
.n
..
. ..
...
. ..
11.8 , .. .
11.6 , . . .
11 1 , .. ,
-1.0
· ..
L .0S
-1.5
1 6 . 1 · . .,
1 1 . ) · . .,
Ll.4 · '-'
-I.'
."
.
L1.1
, . .,
11.1 • '-'
1 1 . 5 · '-'
11 . 6 , . . ,
1 6 . 9 , . .,
-\.)
-\.I
-1.1
·
.
.
_1.0
· ..
-1.6
. ..
...
."
."
. ..
. ..
."
. ..
.<1
bash for compar'tng m i l k prnduc lion
IThe " d i fference r,oo day· indicated ; , u5ed .. ,",
laboratory (-9) and '" last d., or
laboratory Hudy to m i l l:. yields before entering lile
� l
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n
�
,
�
o
�
C
n
"
�
o
=
"
"
.
�
0
,
�
. '"
, =
o
---
�- .�-.;'"
Table 7 .
•
-S
�
< ""
" '<
� �
o 0
�
� �
o
" 3
" .
� '<
"
" �
o 0
=
n
I�
N
·
·
x
�
·
n
,
0
=
�
�
� � O
� '<
�
C •
" c
�
"
·
Comparisons
of treatment effects v1thin each stage and between stages on milk yield,
rectal temperature and water intake.
Milk Production
Rectal Temperature
Water Intake
·c
l/day
kg/ day
Environmental
Stage
Early
Mid
Late
Treatments
SE
(1)
(')
26 . 1 1
.18
A
a
2 3 . 44
.28
B
a
Heat
2 1 . 76
.29
TN
Fa�
TN ,
a
,
Fa�
19.57
.26
C
D
24.58
.10
E
a
a
x
38.5
SE
.10
40 . 1
.07
38.8
.04
SE
( ')
(')
1.3
A
a
1.8
B
a
57.5
1.'
A
a
A
a
B
a
(1)
(2)
A
a
59.8
B
a
70.6
A
a
x
Fa�
22.50
.19
A
b
TN,
1 9 . 52
. 35
B
b
38.8
.02
A
a
57.3
1.3
Heat
1 8 . ))
.32
C
b
39.8
.09
B
b
71.9
1.9
TN
38 . 9
.08
A
a
56.5
1.3
A
a
52.3
1.3
,. I
A
a
,
Fa�
1 5 . 38
.27
D
b
20 . 8 1
. 13
E
b
Fa�
1 8 . 59
.26
A
TN
1 6 . 88
.41
8
,
38.S
. 15
A
a
1 5 . 39
.43
C
,
39 . 7
. 14
B
b
71.2
TN,
13.2
.37
D
,
38.8
A
a
53.2
Fa�
1 6 . 19
. 17
B
,
,
Heat
(l)
x
,
.04
1.3
A B C D E
, , , , lndiCates significance of each treatment within each stage of lactation.
different superscripts are significant «
a b c
( 2 ) , , Compares
significance of each specific
B
a
A
b
Values with
. 05 ) .
treatment among
Values with different superscripts are significant «
E.
.05) .
M
,
or L stage.
Significant a t P . 0 5 .
b
Ta le 8 .
Treat-
ment
SE
Mean daily values and treatment values for milk yield. rectal temperature and water intake .
,
J
Avg .
lIeat
23 . i!
23.4
a
.50
. i! 8
SE
,
.68
19.8
19.0
.57
8
19.7
.61
19.5
16.6
16.9
16.7
a
16.8
SE
,
SE
,
.77
3 8 . i!
38.3
.0 3 i!
38 . 7
.037
38.5
.71
.72
.038
.036
38.8
a
38.5
38.7
a
38.8
.038
.036
38 . 8
a
2 0 . i! b .50
1 6 . 8b
.68
b
39 . 5b
.090
a
3 9 . 2b
.061
Avg .
2 1 .7
16.4
18.3
13.6
.77
40 . 6
. 1 06
40 . 0
. 12 1
7
8
9
Avg.
19.9
.43
b
15.4
b
.71
.51
1 1 . 7b
12" b
. 76
.53
17.4
.44
14.5
. 72
20 . \
.42
19.5
1 5 . 9b
.53
. 55
.54
20.8
b
.53
.46
1 3 . 1b
1 4 . 3b
1 8 .Db
1 9 .0b
1 B . Jb
1 6 . 2b . 4 6
15.4
1 4 . 1b
13.3
.72
. 20
4 0 . 3b
. 1 00
40 . 1
b
39 . 6
a
38.4
8
38 . 7
8
38 . 7
. 1 19
.076
. 08 1
.063
38.8
b
. Compares significance of day 3 with days 4 thru
40 . 1 b
39 . 8
Water Intake.
Earll:
Mid
Late
,
a
.43
a
2 2 .0b . 4 5
•
i
C
SE
23.6
10
8
.53
23.6
23.2
,
Rectal Temperature.
Earll:
Mid
4
5
6
TN,
SE
_
Days _
x
I
TN l
Milk Yield kg/ day
Late
Middle
Earll:
SE
,
SE
. 030 ;: 6 2 . i! 2 . 38
2 . 23
3 8 . 6 .033 60 . 5
a
a
3 8 . 7 .0 3 2 5 5 . 8
2 . 46
38.5
59.8
�
.091
b
39 . 8
.0 6 2
a
38.5
.051
8
38.5
.0 4 2
8
38 . 6
.043
38.9
b'
a
3 8 . 9 b . DB S 76 . 7b 2 . 63
3 9 . 8 b · 1 20 7 2 . 9b 2 . 56
40.3
39.7
. 1 1 1 67.9
70.6
b
3 9 . 7 .082
a
3 8 . 4 .042
8
38 . 5 .040
a
3 8 . 6 .039
38.8
a
60 . 3
8
53.5
8
55 . 5
8
57.B
Late
,
2 . i!3
51.0
52.1
2.11
60 . 0
a
58.7
2.15
2 . 73
1 . 88
a
54.5
57.5
2 . 80
52.3
b
7 9 . 1 b 2 . 99
b
6 6 . 8 b 3 . 00
7 7 . \ 3 . 64
6 9 . 5b 3 . 63
71.9
71.2
2 . 23
54.9
2 . 60
57.5
58 . 7
70.3
2 . 40
SE
,
3.16
2 . 30
1 / d ay
54.4
57.5
60 . 1
3 . 58
8
8
a
a
56.5
66.9
3.81
a
2.4
a
2 . 43 5 3 . 0
2 . 02
a
2.5J 55.3
3 . 03
a
2 . 58 4 9 . 2
2 . 57
2 . 65 5 1 . 8
53 . 2
II.
Values with different superscripts are significant (P< . 05 ) .
�
Table 9 .
condition,!;
Feed, mill. and milk./feed energy during TN ane heat
Treat
D.y
mcnt
Feed
Mcal/dlll
2 f! . 7
TN , :
2 7 . f!
Ave.
us:
Ave .
TN
2
8
ID
Ave.
Early
Hill<
Melll/dllv
15.9
26.9
MUltI
Feet
.S9
.58
Su!:� 01 t..aet�tioD
Fl!ed
MCIll/da
l
Mid
Mill<
Heal/dll'\'
I
Milk/
Feed
Feed
Heal/dllv
l.a«
Hm
Heal/dal
M1lkl
Feed
2B.7
13.1
."
29.8
11.3
.38
28.6
13.4
.48
29.S
11.4
.39
.38
.38
27.9
15.9
.57
28.6
13.5
.47
29.7
11.4
27.4
19.9
.58
28.6
13.3
.47
29.8
1 1 . l;
26.0
49.5
11.4
.44
( . 23)
25.9
(56.1)
16.1
.62
( .29)
26.l;
(49.9)
13.9
.53
( . 28)
21.2
(51.4)
15.0
.71
( . 29)
22.5
(46.0)
12.5
.56
(.27)
22.0
45.5
10.9
."
( . 21,)
19.1
(49.3)
13.6
.71
( . 28)
18.2
(41.7)
1 1 .2
.62
(.26)
18.S
42.3
'.3
."
(.22)
22.1
(56.6)
1 1, . 9
.68
( . 28)
23.4
(4S.8)
12.5
.57
(.27)
22.2
10.5
45.7
22.7
(52.9)
12.3
.54
( .23)
22.0
(45.5)
8.'
.4D
( . 20)
21.2
44.7
8.D
22.3
(52.5)
12.96
.58
( . 25)
24.5
(4B.0)
'.7
.4D
( . 20)
25-'
48.9
8.'
.33
( . In
.48
( .23)
.38
( .IS)
23.6
13.8
.S9
25.9
11.0
.42
26.3
, .6
.37
25.&
14.2
.55
26.7
U.8
."
27.0
,.,
.37
.42
25.0
'.1
.36
23.5
13.4
.57
24.B
10.4
Sody "eight
I
inc:lud1ng feed intak.e and body "eight loss.
( ) Datil 11'1 pllrentheses refer to Total lielll/day
Helll (!rody,
esticated using: 2 . 1 I: It. 10n/5 days I: I . SIL
lOBI du�il\& dllY.r; (4-8) in teres of I'ICill 10:111
1945, p.53, S40).
_.
�
•
•
·
�
�
•
n
n
�
<�
.=. ::
•
•
o
•
•
.
, -�
n ,
� ­
.
.
• •
� n
.
n
•
�
•
n ,
� ;:.
�
n
·
n
�
n o
· ,
,
n
•
· •
�
n
, 0
- ,
� Q.
•
o
n
0
0
-.
:;< n
·
�
O·
�
� ,
�
r
temper a t u r e . water intake,
D.F.
Sum
of
Squares
F
Intake
Sum
•
,
"
::-
,
-1 ::: -1
:;:: no z
N ._
.... = ....
, . ,
N _
n
-I = '"i
2: <10 ":::
N _
n
•
,
� n
A '
. � •
­
o . �
�
,
�
o
• 0
-
"'
.... g'
•
<
· -
�
•
n
n
O
N N N
� N �
•
N N N
. N �
0 ;"' ;"
0
n
� .
�W
N N N
..... .... ....1
:... :... ;."
•
W � W
N � O
N :- .....
� � �
!: ;:; �I
• •
o <
n
�
>
n . >
n . >
n
� . �
• > •
� � �
.,.. ...... .....
� O -I
CD
...... "',
_ 0
�
, 0
- ,
n ,
� .
� .
� �
o 0
· ,
0
, ,
o ,
o
•
_ 0
•
� � �
� N N
- .....
N N W
""
o n
n 0
· ,
N � �
� N �
, �
� O �
n .
•
n
>
�
% ;
o
� -
��
'g �
;
n n
"
.
n 0
- 0
»
� ;:
n
• 0
>
»
>
»
n n n
,
net energy
� � �
•
n
�1�lI:l
,
•
_ n
•
�
•
� �
n
n
! ;;
• 0
o
· , 0
� .
�
;: ,:::
� ,
•
•
•
•
o
•
n
� �
•
o
tnl;o<"�
�
>
c
•
.;;
�
� .
o n
� .
� �
,
.
o •
- 0
� �
�
�
o
i
•
n
o
n
, n
0 0:. 0-1
- N O
- � �
o
-�
N N '
• n
n
n 0
- ,
O �
, .
•
•
o
;c: ­
'
0
� -
� n
- >
n
n 0
• •
•
o •
-
_ 0
0 _
,
o
>
n
< �
•
·
>
n �
� ;;
_ n
•
�
n
,
n
0
•
0 �
n ,
..
_ 0
�
r �
n
•
•
,
• • >
intake and body weight
environmen tal treatment and interaction.
Water
Rectal
Temperature
_ o
e�
o
� ,::: n
_
n
- >
•
n
n
·
as a f f e c ted by stage of l a c t a t i o n ,
n
• n
� 2.
ANOVA table for rectal
�
>
; � t::;
n
•
11.
-
,
-
� -
:; �
-,
Table
•
�
-�
3�
r n
� O
of
51uares
F
Net Energy
Body
Intake
Weight
Sum o f
Squares
F
Sum
of
Squares
F
S t age of
lactation
Environmental
Temperature
Stage x
Temperature
*P< . 05
2
9 . 3246
2
414.6619
4
1 9 . 7228
1. 94
86 . 1 2 '
2 . 05
3645 . 1 605
4 . 93 '
36 5 . 6 5 3 5
6 . 34*
233360 . 5 168
2 1 . 4 3'
70309 . 80 2 4
95 . 1 1'
8325.5221
144 . 24 '
32370 . 7098
2.97*
287 . 2434
2 . 49 *
5427. 1967
2391 . 57 7 9
1 . 62
.25
"
...
I ' ;
"
;
Early
l � j J ; I I ;��;
� l l ��i; l ;;l
Middle
,.
late
D a � � .. ... .. � .. ...
:'! = :: i :i :i J:i ;i :: � ':
i
,
THI . T...2 , n.,mone",•• ,III'C, tl6" IIH
"
1 1 "::�::"' 1 e :: .!: ;: :l::: �::� ::: ::: � I ;:
,
!
Ii ' "'ul,32'C.tlO,,1I1l
� !: ::: !: ;:; = � .. �:. I
�����::�� I � � I :���::��:�� ::: I : � I :::�
�,
,
,
f
'III::: I I
,
"'
-j
:;"" 1 . 1
' 1 11 1 1 1 1 1
::-:: � �::: "! I I
Figure
I.
Average daily milk production for each stage of lactation
group compared with expected milk yields.
Expected mU k yields (---)
b
were ased on average persl.stency decline of cows dueing lactation in
which cow.!! were 011 experiment .
Expected mt tk yields ( . . . . . ) using TN
I.evels as bases of post-heat (TN )
2
recovery.
]
Sham
Ino heatl
Milk Production
r..........
39
P
�
2
3
'
�
II
..
... . .�
3
4
5
Days
n
6
7
8
9
10
11
'.,
Figure 3 :
Sham environmental heat period e f ( ll c t s o n milk production and
Figure
2.
rectal
temperatures for
per iod were l 8 o e ,
"
,.-,- �.-
,-�
'N, -
!
38.5
30
1
YI:;l
During TN, -Heal and
'
:
Reclal Temp.
a l O r l C Int e k e , M i l k
s n d Thermal Balance
�
,
:
!c
6
60% RII.
cows .
Conditions during the sham "no heat"
This trial was desJgned
to dis tinguish the
heat-stresfling effects [rom other environmental fnctors.
'.,
Compa r a t ive energy responses
ylald and associated rectal
"
.
. , . . ......
,,- -7-- - - ,..,
of
dsi ly feed intake and m ! lk
temperatures during
TNl'
Heat and
exposures for Early. Mid and Late stages of lactat o n .
TNZ
Reetel Temp., ''c [RI
Milk Prod., " Doelino IMI
Food Intaka, Meal/day IFI
40
30
"
30
20
>-
U
Z
UJ
=>
a
UJ
a:
u.
10
Intelm.
RM [RT x M P % [
(
\
:
(> .!8)
[<6.5)
+
RMF RT .. [MPl(. + F Meal/day])
Inlorm
Q)
-
I> 12.5)
'"
...J
All Classifications
40
30
30
"
+
IntOlm.
PRODUCTIVE ADAPTA B I L I T Y
Freq uency designations (--) "H')
(+) or intermediate for produetiv,
adtaptabil1ty i nd iees (R, M, F, RM and
Indiv ldIlsl values were baaed
·
o n Day J (TN) versus Day 6 ( 3rd day hea t) d ,£ ferences.
Figure 4 .
.2
'"
-
0
'"
...J
'0
Q)
'"
'"
-
CJ)
:2
::0
Appendix I (Cont)
Appendix I
Cow (J
-;;os
Early
Nid
6/,8
525
ill
829
675
77)
857
572
61)
610
Late
7T6
592
767
Average
61.6
575
736
571
989
5(,9
555
562
555
961,
497
515
528
51 )
880
5 2 /.
632
578
919
1,67
556
511
7
(, 58
526
1,92
1
461
506
1,81,
9
507
53)
520
5
524
528
526
608
589
599
8/,f,
1,61
19
(,5 9
501,
11
1, 2 6
M,6
856
561
582
6)
9/, 2
1, 70
559
529
8
t.t. )
558
1.2)
1,63
M, )
4
510
51,S
559
58)
1.3 6
592
14
511
'5 1 6
535
512
27
527
551
560
5/,6
26
528
541
53)
534
»
1,92
529
53)
518
608
609
627
64)
(, 2 6
686
650
662
687
(,66
990
58/.
606
662
617
101,
(, ) 7
1, 46
1,67
1, 5 7
BRO
590
606
675
621,
999
49/,
506
55/,
518
984
571
585
662
606
53
1, 2 9
456
498
(, 6 1
'"
677
690
700
689
64
(, 90
518
555
521
58
454
510
505
(,90
75
42)
1, 9 0
505
(, 7 2
966
5t.6
596
6)7
59)
100
49)
1.60
476
1, 76
91
4)1
1, 2 7
1,l,7
(,35
90
53)
556
578
556
1
53)
55)
58)
S57
16
600
650
675
6(, 2
1 0f,
S25
5 2 /,
57)
5 1 .!
,
Late
Average
Early
Mid
f, 9 1
1, 90
507
3)
596
61 (,
660
623
95
508
556
51,6
537
9/.2
6/00
5 1 /,
656
690
662
9J
5(,6
51,4
535
925
614
615
Cow ,
,,-
US!)A Study
flody Weight!> (kg)
496
615
20
551
551
106
1 01 7
482
)95
(, 2f 1
1, 2 9
101
1,50
506
591
116
509
532
514
518
109
407
1,65
"' , 7
1,40
)"
58)
600
571
585
J8
597
6)0
589
605