VARIATION IN THE UDDER SURFACE TEMPERATURE OF
DAIRY COWS MEASURED BY THERMAL IMAGING
DeNetra C. Griffin, Michael R. Murphy, James H. Baltz,
and Kathryn E. Cowles
TAKE HOME MESSAGE

Breed, stage of lactation, and time of milking can affect udder temperature.
INTRODUCTION
Our primary objective is to eventually examine how udder temperature, as a measure of core
body temperature, is affected by milk production and environmental conditions; however, the
goal of this study was to assess the effects of breed, stage of lactation, and time of milking on
udder temperature. Others have measured changes in udder and rectal temperatures throughout
the day and the effects of mastitis on udder and rectal temperatures.
MATERIALS AND METHODS
A Fluke (Everett, WA) portable infrared camera was used to measure the udder surface
temperature of 45 dairy cows at the University of Illinois at Urbana-Champaign. Cows were
divided into blocks consisting of 15 high-producing Holsteins (>100 lbs of milk/day), 15
median-producing Holsteins (<90 lbs of milk/ day) and 15 high-producing Jerseys (about 65 lbs
of milk/day). Udder temperatures were recorded for three consecutive milkings (8:30 p.m., 4:30
a.m., and 12:30 p.m.) on one cool day (about 68°F). The temperatures recorded were compared
to the normal body temperature for cows (101.5 °F).
RESULTS AND DISCUSSION
Udder surface temperatures differed throughout the day (P < 0.01); high and low udder
temperatures were both greater at 4:30 a.m., than at 8:30 p.m. or 12:30 p.m. These differences in
temperature seem to follow the cows’ natural circadian rhythms and have been documented in
various other studies.
High and low udder temperatures at 12:30 p.m. and low udder temperatures at 8:30 p.m. were
greater for median-producing than for high-producing Holsteins. It is known that body
temperature of cows rise in late pregnancy; however, median-producing Holsteins in the present
study were just entering their second trimester of pregnancy and 44.5 days further into gestation
than the high-producing Holsteins.
Low udder temperatures of high-producing Jersey cows were greater than those of highproducing Holsteins at 8:30 p.m. and 12:30 p.m. Although why this occurred is not known, it
may be related to the effect of body size on basal metabolic rate.
42
Table 1. Least squares means of high and low udder temperatures, performance and
reproductive status of high-producing Holstein(HH), median-producing Holstein (MH), and
high-producing Jersey (HJ) cows on a 68°F-day recorded for three consecutive milkings (1 to 3).
Item
Treatment
HH
MH
HJ
SEM
(n=15) (n=15) (n=15)
P<
Contrasts
HH vs. HJ HH vs. MH
High 1,°F
99.7
100.3
99.5
0.31
0.1513
0.4921
0.2066
High 2,°F
100.2
100.2
99.8
0.18
0.1637
0.0996
1.0000
High 3,°F
99.2
100.1
99.2
0.30
0.0476
0.8734
0.0389
Low 1,°F
88.3
91.4
91.6
0.80
0.0079
0.0060
0.0076
Low 2,°F
92.3
92.3
92.7
0.42
0.6936
0.4576
0.9910
Low 3,°F
88.9
91.1
92.5
0.60
0.0003
<0.0001
0.0087
4% FCM,
kg
40.2
35.1
32.5
0.98
<0.0001
<0.0001
0.0004
Fat, %
2.95
3.32
4.03
0.122 <0.0001
<0.0001
0.0362
Protein,%
2.77
2.97
3.16
0.05
<0.0001
<0.0001
0.0111
SCC x
1000/ml
92.2
43.2
133.6
35.42
0.2073
0.4125
0.3336
DIM
156.1
236.8
158.3
24.39
0.0375
0.9494
0.0241
Days until
due
232.9
188.4
230.7
14.27
0.0280
0.9093
0.0171
43
Figure 1. Infrared thermogram of cow udder just prior to milking.
44