Effects of pre-harvest electrolyte supplementation on the hydration and meat quality of cull dairy cows

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Effects of pre-harvest electrolyte supplementation on the hydration and meat quality of cull dairy cows
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Crosswhite, J. D.
Arp, T. S.
Carr, C. C.
Johnson, D. D.
Thrift, T. A.
Warnock, T. M.
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University of Florida
Place of Publication:
Gainesville, Fla.

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Effects of Pre-harvest Electrolyte Supplementation on the Hydration and
Meat Quality of Cull Dairy Cows

J. D. Crosswhite, T. S. Arp, C. C. Carr, D. D. Johnson, T. A. Thrift, and T. M. Warnock1


Pre-harvest electrolyte treatment of cull dairy cows improved beef quality and animal hydration, especially
when cows were subject to periods of hot, humid weather and a longer feed withdrawal. However,
electrolyte treatment did not affect dressing percentage.


Summary
Two studies were conducted to evaluate the
effect of pre-harvest electrolyte supplementation
on the hydration and beef quality of cull dairy
cows. Cows were withheld from feed prior to
harvest for 36 or 24 h and ambient temperature
ranged from 72 to 900F or from 54 to 63F for
Exp. 1 and 2, respectively. In Exp. 1, cull dairy
cows (n 60) were orally drenched with 0.4 gal
of water (CON; n 30) or 0.4 gal of water
containing 1.09 g of dry electrolyte/lb BW prior
to transportation to a processing facility (PRE;
n 30). Cows treated PRE tended (P 0.06) to
remain more hydrated than CON-cows
;l"i, Igli,,it the pre-harvest period. Ribeye
samples from PRE cows exhibited greater drip
loss (P 0.04) and tended (P 0.06) to have a
lower 24-h pH than samples from CON cows. In
Exp. 2, cull dairy cows (n 46) were either
drenched with electrolyte prior to transport
(PRE; n 16), following transport (POST; n
14), or given a placebo volume of water (CON;
n 16). Cows treated PRE tended to have a
lower (P 0.06) percentage of weight loss
during transport than untreated cows. Pre-
harvest electrolyte treatment of cull dairy cows
improved beef quality and animal hydration,
especially when cows were subject to periods of
hot weather and a longer feed withdrawal.

Introduction
The transportation and handling of cattle
destined for harvest are stressors which can
reduce live weight and dressing percentage and
effect meat quality. Considerable research has
been conducted with electrolyte supplementation


of growing (Cole and Hutcheson, 1985) and
finishing cattle (Schaefer et al., 1999), however,
no known work has been reported with cull
cows. Therefore, two experiments were
conducted to assess the impact of dietary
electrolyte supplementation on weight loss,
hydration, and meat quality of cull dairy cows
when supplemented prior to, or immediately
following transportation to harvest facilities.

Materials and Methods
Experiment 1
Sixty culled, lactating dairy cows were used in
Exp. 1 which was conducted over 4 d in mid-
August, 2009 at a commercial dairy operation in
Okeechobee County, Florida. Cows in both
studies were selected based on low milk
production, reproductive failure, and lameness.
Ambient temperature ranged from 72 to 900F,
with an average relative humidity of 75% for the
live cattle portions of the study. At 12 h prior to
the start of the study, cows were removed from
feed, initial body weight (BW) was collected,
and cows were assigned a subjective locomotion
score (1 = normal to 5 = severely lame; Sprecher
et al., 1997). Cows were offered water ad
libitum through the duration of both studies,
except during transportation. Cows were
stratified by initial BW and days in lactation
(DIL) into either the control treatment (CON) or
on-farm electrolyte supplemented treatment
(PRE).
At 5:00 a.m. the following morning, cows were
placed in a squeeze chute, ear tagged and blood


1Department of Animal Sciences, University of Florida, Gainesville, FL








sampled. A dry electrolyte powder (Table 1)
delivered at 1.09 g/lb of initial BW was
dissolved in 0.4 gal of water. Cows (PRE; n =
30) were orally drenched with 0.4 gal of
electrolyte solution or a placebo volume of water
(CON; n = 30). At 5:00 p.m. cows were loaded
and transported 3 h to a commercial beef
processing facility. Cows were unloaded and
given 7.5 h of rest. At 3:30 a.m. cows were
weighed and blood sampled as described earlier,
prior to being harvested at 7:00 a.m.

Experiment 2
Forty-eight culled, lactating dairy cows were
used in Exp. 2 which was which was conducted
over 4 d in mid-December, 2009 at a
commercial dairy operation in Gilchrist County,
Florida. Cows from Exp. 2 were selected using
the same criteria as Exp. 1. Ambient
temperature ranged from 54 to 630F, with an
average relative humidity of 87% for the live
cattle portion of the study. On d 1, cows were
stratified by initial BW and DIL into 1 of 3
treatment groups: 1) untreated control (CON); 2)
on-farm electrolyte supplementation before
transportation (PRE); and 3) post-transportation
electrolyte supplementation (POST).

At 5:00 a.m. the following morning, cows were
withheld from feed and blood sampled. For the
PRE- treatment, cows (n = 16) were orally
drenched the same as in Exp. 1, whereas CON-
and POST-cows (n = 16 and 14, respectively)
received a placebo volume of 0.4 gal of water.
At 2 p.m. cows were loaded and transported 2 h
to a commercial beef processing facility,
unloaded and placed in holding pens. At 5 p.m.
cows were weighed and samples collected as
described earlier. Cows (POST; n = 14) were
administered an electrolyte treatment using the
previously described procedure, with CON- and
PRE- cows given a placebo volume of 0.4 gal of
water before being returned to their holding
pens. At 4 a.m. cows were weighed and
sampled as described earlier, prior to being
harvested at 10:00 a.m.

Carcass data, pH, and objective lean color (L*,
a*, b*) of the ribeye (RE) and semimebranosus
(SM) were collected by university personnel, for
both experiments, at 24-h postmortem from left
carcass sides.


Data were analyzed as a completely randomized
design with individual cow as the experimental
unit for all variables measured. The mixed
models procedure of SAS (SAS Inst. Inc., Cary,
NC) was used to test the model. Locomotion
score and DIL were used as covariates in both
models. Least square means were calculated for
the lone fixed effect of electrolyte treatment, and
separated statistically using pair-wise t-tests (P-
DIFF option of SAS) when a significant
(P<0.05) F-test was detected.

Results
Initial and pre-harvest BW were similar across
treatments in Exp. 1 and 2. However, in Exp. 2,
BW shrink during transportation tended to be
less (P = 0.06) in PRE-cows than in CON- and
POST-cows (8.58 vs 12.45 % loss, respectively).
The tendency for electrolyte-treated cows to lose
less BW than untreated cows is consistent with
the findings of Gortel et al. (1992) and may be
attributed to an increase in water intake in
response to increased sodium intake.

In Exp. 1, PRE-cows tended (P < 0.08) to have
lower packed cell volume (PCV) values, an
indicator of improved cell hydration, throughout
the pre-harvest period than CON-cows (Table
2). Electrolyte treatment did not affect PCV
values of cows in Exp. 2.

Carcasses of PRE-cows had more (P = 0.03)
marbling within the ribeye than carcasses of
CON- or POST-cows in Exp. 2 (Table 3).
Otherwise, electrolyte supplementation did not
affect (P > 0.12) any carcass trait in Exp. 1 or 2
(Table 3).

The RE of PRE-cows tended (P = 0.06) to have
a lower 24-h pH value compared to the RE of
CON-cows in Exp. 1 (Table 4). Electrolyte
supplementation did not affect pH (P > 0.35) of
either muscle in Exp. 2, nor the SM in Exp. 1
(Table 4). Beef products with elevated pH
values are undesirable due to having a reduced
product shelf-life (Faustman and Cassens, 1990)
and potentially resulting in ground beef with
some degree of redness remaining after cooking,
or "persistent pinking" (Hunt et al., 1999). The
elevated RE pH values in Exp. 1 were likely
impacted by handling cows multiple times for
blood collection and weighing in the hot, humid








environment. Electrolyte supplementation of
fed cattle has been shown to increase muscle
glycogen antemortem, allowing for a more
complete postmortem pH decline of postmortem
muscle (Schaefer et al., 1999).

The RE from CON-cows had a lower (P = 0.04)
drip loss percentage than the RE from PRE-cows
in Exp. 1 (Table 4). Objective color (L*, a*, and
b*) values of the RE and SM did not differ (P >
0.11) between treatments in either Exp. 1 or 2
(Table 4). However, in Exp. 1, SM samples
from PRE carcasses had numerically greater L*
and a* values than samples than CON carcasses,
suggesting a relationship to the lower, more
normal final pH exhibited by PRE cows. Beef
with a 24-h pH closer to 5.2, the isoelectric point
of muscle, would be expected to have decreased
water-holding capacity and a lighter color
(Lawrie, 1958).


dosages, and times of delivery should be
conducted to determine if pre-harvest
supplementation can increase dressing
percentage of cull cows. Also, future trials
should incorporate the electrolyte within the
water source, allowing ad libitum access, to
simulate commercial applications. Electrolyte
supplementation costs were approximately $ 2 -
5/cow in the current research; therefore,
increased value from improved dressing
percentage and beef quality will have to exceed
supplementation costs to be commercially
viable.


Conclusion
Pre-harvest electrolyte treatment of cull dairy
cows improved beef quality and animal
hydration, especially when cows were subject to
periods of hot, humid weather and a longer feed
withdrawal. However, non-fed beef processors
in the U.S. primarily purchase cull cows on
carcass weight; thus, dressing percentage is of
paramount importance. More trials with a
greater number of animals, varying electrolyte






Literature Cited
Cole and Hutcheson. 1985. J. Anim. Sci. 60:772.
Faustman and Cassens. 1990. J. Muscle Foods 1:217.
Gortel et al.1992. Can. J. Anim. Sci. 72:547.
Hunt et al. 1999. J. Food Sci. 64:847.
Lawrie 1958. J. Sci. Food Agric. 9:721.
Schaefer et al. 1999. Can. J. Anim. Sci. 79:592.
Sprecher et al. 1997. Theriogenology. 47:1179-1187.
USDA-AMS. 1997. United States standards for grades of carcass beef.


The authors would like to sincerely thank Mr. Jacob Larson and his staff at Larson Dairy Inc.,
Okeechobee, FL and Mr. Don Bennick and his staff at North Florida Holsteins, Bell, FL. The authors
would also like to thank the management and staff at Central Beef Industries LLC, Center Hill, FL.
















Table 1. Ingredients of electrolyte supplement
Ingredient %

Dextrose 94.8

Sodium bicarbonate 2.7

Potassium chloride 1.5

Magnesium sulfate 1.0













Table 2. Effect of on-farm electrolyte supplementation on packed cell volume (PCV) of whole blood
for Exp. 1
Treatment'
Variable CON PRE SEM P-Value
Initial PCV, % 35.85 35.34 0.70 0.62
Pre-harvest PCV, % 36.40 34.62 0.68 0.08

PCV Change, % 1.63 -1.74 1.20 0.06
'CON; orally drenched with 0.4 gal of water. PRE; orally drenched with 0.4 gal of water containing 2.4
g of dry electrolyte per kg BW
2From blood taken approximately 36 h after initial measurement and feed withdrawal.














Table 3. Carcass characteristics by treatment group for Exp. 1 and 2

Exp. 1 Exp. 2

Treatment' CON PRE P-Value CON PRE POST P-Value
No. of observations 30 30 16 16 14
Dressing % 53.0 + 0.7 53.2 + 0.7 0.83 51.1 + 1.1 50.1 + 1.1 49.8 + 1.2 0.65
Hot carcass wt, lbs 728.9 + 21.6 670.1 + 21.6 0.51 724.7 + 26.2 708.1 + 26.2 309.0 + 28.4 0.54

Fat thickness, in 0.20 0.03 0.19 0.03 0.93 0.11 0.03 0.12 0.03 0.05 0.03 0.22

Ribeye area, sq. in 10.5 + 0.4 10.5 0.4 0.94 9.1 + 0.5 9.3 0.5 8.9 + 0.5 0.84

USDA YG2 2.8 0.1 2.7 0.1 0.65 3.1 0.1 3.0+ 0.1 2.9 0.2 0.58

Overall Maturity3 432 +18 407 +18 0.32 418 30 430 30 506 32 0.12

Marbling4 408 + 28 426 + 28 0.66 392 39ab 459 39a 302 42b 0.03

'CON = orally drenched 0.4 gal of water before (Exp. 1) or before and after transportation (Exp. 2); PRE = orally
drenched with 0.4 gal of water containing 1.09 g of dry electrolyte/lb BW before transportation; POST = orally drenched
with 1.5 L of water containing 1.09 g of dry electrolyte/lb BW after transportation
2A standard 2.5% KPH fat was used when calculating USDA yield grades (USDA-AMS, 1997).
'200 to 299 = B maturity; 300 to 399 = C maturity; 400 to 499 = D maturity; 500 to 599 = E maturity.
4300 to 399 = Slight; 400 to 499 = Small; 500 to 599 = Modest.
abWithin a row, values lacking a common superscript differ (P<0.001).

















Table 4. Effect of electrolyte supplementation on pH and objective color measurements of the ribeye (RE) and
semimembranosus (SM) and RE drip loss for Exp. 1 and 2
Exp. 1 Exp. 2

Treatment' CON PRE P-Value CON PRE POST P-Value
No. of observations 30 30 16 16 14
3-h RE pH 7.02 + 0.07 7.14 + 0.07 7.03 0.07 0.43
24-h RE pH 5.91 0.04 5.81 0.04 0.06 5.67 0.03 5.69 0.03 5.68 0.03 0.89
RE Lightness (L*)2 32.99 + 0.82 34.38 + 0.82 0.25 22.62 + 0.99 22.10 + 0.99 20.63 + 1.07 0.39
RE Redness (a*)3 18.43 0.60 19.25 0.60 0.35 25.28 0.77 24.17 0.77 24.51 0.83 0.58
RE Yellowness (b*)4 15.08 0.45 15.99 0.45 0.17 20.41 0.62 19.11 0.62 19.17 0.67 0.27
RE drip loss, % 0.61 0.21 1.26 0.21 0.04 1.79 0.27 1.20 + 0.27 0.91 0.30 0.10
24-h SM pH 5.90 + 0.03 5.85 + 0.03 0.35 5.64 + 0.03 5.66 + 0.03 5.67 + 0.03 0.81
SM Lightness (L*)2 28.32 0.78 29.80+ 0.78 0.19 20.42+ 1.30 19.95+ 1.30 21.48+ 1.41 0.73
SM Redness (a*)3 20.40+ 0.66 21.95 0.66 0.11 25.68+ 1.04 27.55+ 1.04 25.95+ 1.13 0.40
SM Yellowness (b*)4 15.78 + 0.63 17.25 0.63 0.11 19.67 + 0.80 19.96 + 0.80 20.23 0.87 0.89
'CON = orally drenched 0.4 gal of water before (Exp. 1) or before and after transportation (Exp. 2); PRE = orally
drenched with 0.4 gal of water containing 1.09 g of dry electrolyte/lb BW before transportation; POST = orally drenched
with 1.5 L of water containing 1.09 g of dry electrolyte/lb BW after transportation
2L* = measure of darkness to lightness (greater value indicates a lighter color)
3 a* = measure of redness (greater value indicates a redder color);
4b* = measure of yellowness (greater value indicates more yellow color).




Full Text

PAGE 1

Summary Two studies were conducted to evaluate the effect of pre harvest electrolyte supplementation on the hydration and beef quality of cull dairy cows. Cows were withheld from feed prior to harvest for 36 or 24 h and ambient temperature ranged from 72 to 90F or from 54 to 63F for Exp. 1 and 2, respectively. In Exp. 1, cull dairy cows (n = 60) were orally drenched with 0.4 gal of water (CON; n = 30) or 0.4 gal of water containing 1.09 g of dry electrolyte/lb BW prior to transportation to a processing facility (PRE; n = 30). Cows treated PRE tended (P = 0.06) to remain more hydrated than CON cows throughout the pre harvest period. Ribeye samples from PRE cows exhibited greater drip loss (P = 0.04) and tended (P = 0.06) to have a lower 24 h pH than samples from CON cows. In Exp. 2, cull dairy cows (n = 46) were either drenched with electrolyte prior to transport (PRE; n = 16), following transport (POST; n = 14), or given a placebo volume of water (CON; n =16). Cows treated PRE tended to have a lower (P = 0.06) percentage of weight loss during t ransport than untreated cows. Pre harvest electrolyte treatment of cull dairy cows improved beef quality and animal hydration, especially when cows were subject to periods of hot weather and a longer feed withdrawal. Introduction The transportation and handling of cattle destined for harvest are stressors which can reduce live weight and dressing percentage and effect meat quality. Considerable research has been conducted with ele ctrolyte supplementation of growing (Cole and Hutcheson, 1985) and finishing cattle (Schaefer et al., 1999), however, no known work has been reported with cull cows. Therefore, two experiments were conducted to assess the impact of dietary electrol yte supplementation on weight loss, hydration, and meat quality of cull dairy cows when supplemented prior to, or immediately following transportation to harvest facilities. Materials and Methods Experiment 1 Sixty culled, lactating dairy cows were used in Exp. 1 which was conducted over 4 d in mid August, 2009 at a commercial dairy operation in Okeechobee County, Florida. Cows in both studies were selected based on low milk production, reproductive failure, a nd lameness. Ambient temperature ranged from 72 to 90F, with an average relative humidity of 75% for the live cattle portions of the study. At 12 h prior to the start of the study, cows were removed from feed, initial body weight (BW) was collected, and cows were assigned a subjective locomotion score (1 = normal to 5 = severely lame; Sprecher et al., 1997). Cows were offered water ad libitum through the duration of both studies, except during transportation. Cows were stratified by initial BW and day s in lactation (DIL) into either the control treatment (CON) or on farm electrolyte supplemented treatment (PRE). At 5:00 a.m. the following morning, cows were placed in a squeeze chute, ear tagged and blood Effects of Pre harvest Electrolyte Supplementation on the Hydration and Meat Quality of Cull Dairy Cows J. D. Crosswhite, T. S. Arp, C. C. Carr, D. D. Johnson, T. A. Thrift, and T. M. Warnock 1 Pre harvest electrolyte treatment of cull dairy cows improved beef quality and animal hydration, especially when cows were subject to periods of hot, humid weather and a longer feed withdrawal. However, electrolyte treatment did not affect dressing percentage. 1 Department of Animal Sciences, U niversity of Florida, Gainesville, FL

PAGE 2

sampled. A dry electrolyte powder (Table 1) delivered at 1.09 g/lb of initial BW was dissolved in 0.4 gal of water. Cows (PRE; n = 30) were orally drenched with 0.4 gal of electrolyte solution or a placebo volume of water (CON; n = 30). At 5:00 p.m. cows were loaded and transported 3 h to a commer cial beef processing facility. Cows were unloaded and given 7.5 h of rest. At 3:30 a.m. cows were weighed and blood sampled as described earlier, prior to being harvested at 7:00 a.m. Experiment 2 Forty eight culled, lactating dairy cows were used in E xp. 2 which was which was conducted over 4 d in mid December, 2009 at a commercial dairy operation in Gilchrist County, Florida. Cows from Exp. 2 were selected using the same criteria as Exp. 1. Ambient temperature ranged from 54 to 63F, with an average relative humidity of 87% for the live cattle portion of the study. On d 1 cows were stratified by initial BW and DIL into 1 of 3 treatment groups: 1) untreated control (CON); 2) on farm electrolyte supplementation before transportation (PRE); and 3) pos t transportation electrolyte supplementation (POST). At 5:00 a.m. the following morning, cows were withheld from feed and blood sampled. For the PRE treatment, cows (n = 16) were orally drenched the same as in Exp. 1, whereas CON and POST cows (n = 16 and 14, respectively) received a placebo volume of 0.4 gal of water. At 2 p.m. cows were loaded and transported 2 h to a commercial beef processing facility, unloaded and placed in holding pens. At 5 p.m. cows were weighed and samples collected as descr ibed earlier. Cows (POST; n = 14) were administered an electrolyte treatment using the previously described procedure, with CON and PRE cows given a placebo volume of 0.4 gal of water before being returned to their holding pens. At 4 a.m. cows were wei ghed and sampled as described earlier, prior to being harvested at 10:00 a.m. Carcass data, pH and objective lean color (L*, a*, b*) of the ribeye (RE) and semimebranosus (SM) were collected by university personnel, for both experiments, at 24 h postmort em from left carcass sides. Data were analyzed as a completely randomized design with individual cow as the experimental unit for all variables measured. The mixed models procedure of SAS (SAS Inst. Inc., Cary, NC) was used to test the model. Locomotion score and DIL were used as covariates in both models. Least square means were calculated for the lone fixed effect of electrolyte treatment, and separated statistically using pair wise t tests ( P DIFF option of SAS) when a significant ( P <0.05) F test was detected. Results Initial and pre harvest BW were similar across treatments in Exp. 1 and 2. However, in Exp. 2, BW shrink during transportation tended to be less ( P = 0.06) in PRE cows than in CON and POST cows (8.58 vs 12.45 % loss, respectively). T he tendency for electrolyte treated cows to lose less BW than untreated cows is consistent with the findings of Gortel et al. (1992) and may be attributed to an increase in water intake in response to increased sodium intake. In Exp. 1, PRE cows tended ( P 0.08) to have lower packed cell volume (PCV) values, an indicator of improved cell hydration, throughout the pre harvest period than CON cows (Table 2). Electrolyte treatment did not affect PCV values of cows in Exp. 2. Carcasses of PRE cows had more ( P = 0.03) marbling within the ribeye than carcasses of CON or POST cows in Exp. 2 (Table 3). Otherwise, electrolyte supplementation did not affect ( P 0.12) any carcass trait in Exp. 1 or 2 (Table 3) The RE of PRE cows tended ( P = 0.06) to have a low er 24 h pH value compared to the RE of CON cows in Exp. 1 (Table 4). Electrolyte supplementation did not affect pH ( P 0.35) of either muscle in Exp. 2, nor the SM in Exp. 1 (Table 4). Beef products with elevated pH values are undesirable due to having a reduced product shelf life ( Faustman and Cassens, 1990) and potentially resulting in ground beef with some degree of redness remaining after cooking, The elevated RE pH v alues in Exp. 1 were likely impacted by handling cows multiple times for blood collection and weighing in the hot, humid

PAGE 3

environment. Electrolyte supplementation of fed cattle has been shown to increase muscle glycogen antemortem allowing for a more com plete postmortem pH decline of postmortem muscle (Schaefer et al., 1999). The RE from CON cows had a lower ( P = 0.04) drip loss percentage than the RE from PRE cows in Exp. 1 (Table 4). Objective color (L*, a*, and b*) values of the RE and SM did not di ffer ( P 0. 11 ) between treatments in either Exp. 1 or 2 (Table 4). However, in Exp. 1, SM samples from PRE carcasses had numerically greater L* and a* values than samples than CON carcasses, suggesting a relationship to the lower, more normal final pH e xhibited by PRE cows. Beef with a 24 h pH closer to 5.2, the isoelectric point of muscle, would be expected to have decreased water holding capacity and a lighter color ( Lawrie, 19 58 ). Conclusion Pre harvest electrolyte treatment of cull dairy cows improv ed beef quality and animal hydration, especially when cows were subject to periods of hot, humid weather and a longer feed withdrawal. However, non fed beef processors in the U.S. primarily purchase cull cows on carcass weight; thus, dressing percentage i s of paramount importance. More trials with a greater number of animals, varying electrolyte dosages, and times of delivery should be conducted to determine if pre harvest supplementation can increase dressing percentage of cull cows. Also, future trials should incorporate the electrolyte within the water source, allowing ad libitum access, to simulate commercial applications. Electrolyte supplementation costs were approximately $ 2 5/cow in the current research; therefore, increas ed value from improved dressing percentage and beef quality will have to exceed supplementation costs to be commercially viable. The authors would like to sincerely thank Mr. Jacob Larson and his staff at Larson Dairy Inc. Okeechobee, FL and Mr. Don Bennick and his staff at North Florida Holsteins, Bell, FL. The authors would also like to thank the management and staff at Central Beef Industries LLC, Center Hill, FL. Literature Cited Cole and Hutcheson. 1985. J. Anim. Sci. 60:772. Faustman and Cassens. 1990. J. Muscle Foods 1 : 217. Gortel et al.1992. Can. J. Anim. Sci. 72:547. Hunt et al. 1999. J. Food Sci. 64:847. Lawrie 1958. J. Sci. Food Agric. 9:721. Schaefer et al. 1999. Can. J. Anim. Sci. 79:592. Sprecher et al. 1997. Theriogenology. 47:1179 1187. USDA AMS. 1997. United States standar ds for grades of carcass beef.

PAGE 4

Table 1. Ingredients of electrolyte supplement Ingredient % Dextrose 94.8 Sodium bicarbonate 2.7 Potassium chloride 1.5 Magnesium sulfate 1.0 Table 2. Effect of on farm electrolyte supplementation on packed cell volume (PCV) of whole blood for Exp. 1 Treatment 1 Variable CON PRE SEM P Value Initial PCV, % 35.85 35.34 0.70 0.62 Pre harvest PCV, % c 36.40 34.62 0.68 0.08 PCV Change, % 1.63 1.74 1.20 0.06 1 CON; orally drenched with 0.4 gal of water. PRE; orally drenched with 0.4 gal of water containing 2.4 g of dry electrolyte per kg BW 2 From blood taken approximately 36 h after initial measurement and feed withdrawal.

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Table 3. Carcass characteristics by treatment group for Exp. 1 and 2 Exp. 1 Exp. 2 Treatment 1 CON PRE P Value CON PRE POST P Value No. of observations 30 30 16 16 14 Dressing % 53.0 0.7 53.2 0.7 0.83 51.1 1.1 50.1 1.1 49.8 1.2 0.65 Hot carcass wt, lbs 728.9 21.6 670.1 21.6 0.51 724.7 26.2 708.1 26.2 309.0 28.4 0.54 Fat thickness, in 0.20 0.03 0.19 0.03 0.93 0.11 0.03 0.12 0.03 0.05 0.03 0.22 Ribeye area, sq. in 10.5 0.4 10.5 0.4 0.94 9.1 0.5 9.3 0.5 8.9 0.5 0.84 USDA YG 2 2.8 0.1 2.7 0.1 0.65 3.1 0.1 3.0 0.1 2.9 0.2 0.58 Overall Maturity 3 432 18 407 18 0.32 418 30 430 30 506 32 0.12 Marbling 4 408 28 426 28 0.66 392 39 ab 459 39 a 302 42 b 0.03 1 CON = orally drenched 0.4 gal of water before (Exp. 1) or before and after transportation (Exp. 2); PRE = orally drenched with 0.4 gal of water containing 1.09 g of dry electrolyte/lb BW before transportation; POST = orally drenched with 1.5 L of water containing 1.09 g of dry electrolyte/lb BW after transportation 2 A standard 2.5% KPH fat was used when calculating USDA yield grades (USDA AMS, 1997). 3 200 to 299 = B maturity; 300 to 399 = C maturity; 400 to 499 = D maturity; 500 to 599 = E maturity. 4 300 to 399 = Slight; 400 to 499 = Small; 500 to 599 = Modest. a,b Within a row, values lacking a common superscript differ ( P < 0.001).

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Table 4. Effect of electrolyte supplementation on pH and objective color measurements of the ribeye (RE) and semimembranosus (SM) and RE drip loss for Exp. 1 and 2 Exp. 1 Exp. 2 Treatment 1 CON PRE P Value CON PRE POST P Value No. of observations 30 30 16 16 14 3 h RE pH 7.02 0.07 7.14 0.07 7.03 0.07 0.43 24 h RE pH 5.91 0.04 5.81 0.04 0.06 5.67 0.03 5.69 0.03 5.68 0.03 0.89 RE Lightness (L*) 2 32.99 0.82 34.38 0.82 0.25 22.62 0.99 22.10 0.99 20.63 1.07 0.39 RE Redness (a*) 3 18.43 0.60 19.25 0.60 0.35 25.28 0.77 24.17 0.77 24.51 0.83 0.58 RE Yellowness (b*) 4 15.08 0.45 15.99 0.45 0.17 20.41 0.62 19.11 0.62 19.17 0.67 0.27 RE drip loss, % 0.61 0.21 1.26 0.21 0.04 1.79 0.27 1.20 0.27 0.91 0.30 0.10 24 h SM pH 5.90 0.03 5.85 0.03 0.35 5.64 0.03 5.66 0.03 5.67 0.03 0.81 SM Lightness (L*) 2 28.32 0.78 29.80 0.78 0.19 20.42 1.30 19.95 1.30 21.48 1.41 0.73 SM Redness (a*) 3 20.40 0.66 21.95 0.66 0.11 25.68 1.04 27.55 1.04 25.95 1.13 0.40 SM Yellowness (b*) 4 15.78 0.63 17.25 0.63 0.11 19.67 0.80 19.96 0.80 20.23 0.87 0.89 1 CON = orally drenched 0.4 gal of water before (Exp. 1) or before and after transportation (Exp. 2); PRE = orally drenched with 0.4 gal of water containing 1.09 g of dry electrolyte/lb BW before transportation; POST = orally drenched with 1.5 L of water containing 1.09 g of dry electrolyte/lb BW after transportation 2 L* = measure of darkness to light ness (greater value indicates a lighter color) 3 a* = measure of redness (greater value indicates a redder color); 4 b* = measure of yellowness (greater value indicates more yellow color).