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Superintendent
David Davis
21262 Genoa Road
Linneus, MO 64653
Phone: 660 895-5121
FAX: 660 895=5122
Email:
DavisDK@missouri.edu
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January - March, 2005
Forage Systems Update
Vol 14, No. 1
Evaluation of a Tasco Supplement on Reproductive Rate in Suckled Postpartum Beef Cows
Forage Systems Research Center, Linneus, MO
D. J. Patterson and D. K. Davis
Hypothesis being tested. Tasco supplementation will enhance reproductive
rate and resulting pregnancy in spring calving, postpartum suckled beef cows.
Improvements in pregnancy rate will occur as a result of reduced heat stress.
The effects of heat stress will be minimized as a result of reduced body
temperatures among cows and bulls consuming seaweed supplement.
Experimental treatments. Two treatments were compared. Cows and bulls
assigned to the Tasco treatment consumed supplement beginning approximately 3
weeks prior to a 45-day breeding season, which began on May 8, 2003.
Supplementation continued through completion of the breeding season, through the
summer, and ended on September 1, 2003. The control group was offered a
comparable supplement without Tasco over the same time frame.
Experimental animals.
One hundred fifty-five cows were assigned within age group and by calving date
to one of two treatments. Treatments were balanced by cow body condition score
and breed. Six bulls were assigned to the respective treatments. Each
treatment consisted of 3 replicates with 1 bull and either 25 or 26 cows per
replicate.
Experimental procedures.
Cows: Two blood samples for progesterone were obtained 10 days and 1 day prior
to the initiation of treatment to determine estrous cyclicity rates of cows. An
initial pregnancy exam was performed by ultrasound on July 29, 2003, and the
final pregnancy exam was performed on September 16.
Bulls: An initial breeding soundness evaluation was performed on all
bulls approximately 60 days before the breeding season, immediately prior to the
breeding season, midway through the breeding season, and the day after the
breeding season ended.
Percentage data were analyzed using Chi-square procedures of SAS.
Results. The results are presented in Table 1. There was no difference
between treatments in the performance of cows for the following variables: 1)
initial pregnancy exam, final pregnancy, pregnancy loss or weight change. In
addition there were no notable differences among bulls consuming Tasco versus
control supplements with regard to semen motility, live sperm or concentration.
Conclusion. The results from this study indicate that there was no
change in reproductive response variables among cows consuming Tasco supplement
prior to or during the breeding season.
| Table 1. Response rates for control and Tasco treated groups |
| |
Control supplement |
Tasco supplement |
Rep1 |
Rep 2 |
Rep 3 |
Total |
Rep 1 |
Rep 2 |
Rep 3 |
Total |
| Pretreatment estrous cyclicity ratea |
23/26 |
25/26 |
18/25 |
66/77 86% |
20/26 |
21/26 |
24/26 |
65/78 83% |
| No. preg. (1st preg exam)b |
23/26 |
21/26 |
24/25 |
68/77 88% |
20/26 |
25/26 |
24/26 |
69/78 88% |
| No. preg. (Final preg exam)c |
23/26 |
21/26 |
24/25 |
68/77 88% |
20/26 |
25/26 |
23/26 |
68/78 87% |
| Pregnancy lossd |
0 |
1 |
0 |
1 |
0 |
0 |
1 |
1 |
| Cow weight change (lb)e |
+614 |
+1003 |
-852 |
+765
+9.9 lb/cow |
-199 |
-226 |
+1303 |
+878
+11.2 lb/cow |
| Calf average daily gain (lb/day)f |
2.33 |
2.18 |
2.06 |
2.19 |
2.24 |
2.12 |
2.19 |
2.18 |
| Respiration rateg |
73, 72 |
78, 81 |
79, 75 |
|
76, 75 |
70, 77 |
78, 80 |
|
| Mineral consumption (lb)h |
|
|
|
4330
(56 lb/cow) |
|
|
|
5150
(66 lb/cow) |
aNumber of cows that were estrous cycling at the time treatments were initiated. Estrous cyclicity rate was determined based on two blood samples collected prior to treatment initiation. Cows were considered to be estrous cycling if concentrations of progesterone in serum were elevated (≥ 1 ng/ml) in either one of two samples.
bThe first pregnancy examination was performed with ultrasound on July 29, 2003.
cThe final pregnancy examination was performed on September 16, 2003.
dPregnancy loss was determined on the basis of cows that were diagnosed pregnant after the first ultrasound and that were determined to be open or not pregnant at the final ultrasound.
eCow weight change was determined on the basis of the total weight change of cows within rep and treatment. The initial weight was determined on April 10, 2003 and the final weight was obtained on September 15, 2003.
fAverage daily gain of calves was calculated from the beginning and ending calf weight within rep and treatment. Weights were determined on the same days as indicated above for the cows.
gRespiration rate was obtained weekly for 14 weeks beginning on June 18 and ending on September 15. The two numbers for each rep represent the mean respiration rates for two cows within rep and treatment.
hTotal mineral consumption during the experimental period. |
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