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THE EFFECT OF SYSTEMIC GRUBICIDES ON YEARLING STEERS IN THE FEED LOT

This experiment is being conducted to determine the effectiveness of systemic grubicides for grub control, and the effects of the treatments on feed lot gains. The trial has been in progress for two years.

In both years, 1963 and 1964, yearling Hereford steers were purchased from an area believed to be infested with cattle grubs. The last week in September they were allotted at random into three lots and placed on a ration of corn silage, alfalfa hay, rolled barley and supplement.

One lot was designated as the control lot and received no treatment for grub control. One lot was treated with Co-Ral and one lot was treated with Ruelene.

Grub counts were made in February and March in both 1964 and 1965 and in April 1965. The steers were on feed for 181 days in 1963-64 and 195 days in 1964-65.

Results for the 1964-1965 trial in detail are shown in tables 4 through 6.

Table 4. Results of Grub Control on Feed Lot Performance and Slaughter Value.
Treatment CoRal Check Ruelene
No. of Steers 10 9 10
Days on Feed 195 195 195
Initial Weight 688 687.5 688
Final Weight 1100.5 1080.0 1108.5
Gain 412.5 392.5 420.5
Average Daily Gain 2.12 2.01 2.16
 
Av. Dressed Wt. 598.9 595.7 604.9
Dressing Percent 54.42 55.15 54.57
Average Grade 8 Cho, 2 Gd. 6 Cho, 3 Gd. 7 Cho, 3 Gd.
Av. Carcass Value $222.31 $218.49 $222.52
Av. Feed Cost $60.17 $58.66 $58.64
Profit $162.14 $159.83 $163.88
Feed Cost/100# Gain $14.59 $14.95 $13.95

 

Table 5. Grub Count - Total Grubs Per Lot.
Date CoRal Check Ruelene
February 17, 1965 10 5 13
March 10, 1965 5 22 6
April 7, 1965 5 23 3
Total 20 50 22
Grubs Per Head 2 5.5 2.2

 

Table 6. Average Daily Ration Fed Steers Treated With Systemic Grubicides.
  CoRal Check Ruelene
Silage 31.4# 29.2# 29.2#
Barley 8.7# 8.7# 8.7#
Alfalfa 1.4# 1.4# 1.4#
Supplement 0.8# 0.8# 0.8#

 

Table 7. Two Years Results From the Systemic Grubicide Trial.
  CoRal Check Ruelene
Initial Weight
1963 669 671 665
1964 688 687.5 688
Average 678.5 679.3 676.5
Final Weight
1963 1021 1033 1034
1964 1100.5 1080.0 1108.5
Average 1060.5 1056.5 1071.2
Average Daily Gain
1963 1.94 2.00 2.04
1964 2.12 2.01 2.16
Average 2.03 2.01 2.10
Feed Cost/100# Gain
1963 $16.10 $15.65 $15.86
1964 $14.59 $14.95 $13.95
Average $15.35 $15.30 $14.91
Grub Count Per Head
1963 10.2 10.0 3.8
1964 2.0 5.5 2.2
Average 6.1 7.8 3.0
Dressing % On Home Weight
1963 58.8 58.8 58.1
1964 54.4 55.2 54.6
Average 56.6 57.0 56.4
Pour-On vs Spray
  Pour On Spray   Pour On Spray
Gain 419 406   444 397

Results

The results from the 1964-65 trial show that both treatments, CoRal and Ruelene, were effective in the control of cattle grubs. Although both treatments gave slightly faster gains than the control, the difference could not be considered significant. When feed costs per 100 pounds gain are considered, the Ruelene treated animals averaged one dollar per hundred less than the controls. The control steers averaged slightly higher dressing percentages than either chemical treatment.

This experiment was hindered by a lack of grub larva in all animals. An added benefit, the control of cattle lice, was observed in both lots of treated steers.

The two year average (shown in table 7) shows that both CoRal and Ruelene significantly reduced the grub numbers. There appeared to be no significant difference between the rate of gain or dressing percentage. The Ruelene treated steers were slightly more efficient, putting on 100 pounds of gain for approximately .40 less than the other treatments.

The pour-on method of application gave faster gains did the high pressure spray method.

Average results for this trial for the two years are summarized in tables 8 through 16.

Table 8. Effects of Systemic Grubicides on Spring Grub Counts and Weight Gains When Used on Yearling Steers in the Feed Lot, in 1963-64.
Treatment Initial
Weight
Final
Weight
Average
Daily Gain
TDN Per
100 lbs. Gain
Feed Cost Per 100
lbs. Gain
Average Grub
Count Per Hd.
Control 671 1033 2.00 642 $15.65 16.0
Co-Ral 669 1021 1.94 660 $16.10 10.2
Ruelene 665 1034 2.04 651 $15.86 3.8

 

Table 9. Effects of Systemic Grubicides on Spring Grub Counts and Weight Gains When Used on Yearling Steers in the Feed Lot in 1964-65.
Treatment Initial
Weight
Final
Weight
Average Daily Gain TDN Per
100 lbs. Gain
Feed Cost Per 100
lbs. Gain
Average Grub
Count Per Hd.
Control 688 1080 2.01 603 $14.95 5.5
Co-Ral 688 1101 2.12 588 $14.59 2.0
Ruelene 688 1109 2.16 562 $13.95 2.2

 

Table 10. Effects of Systemic Grubicides on Spring Grub Counts and Weight Gains When Used on Yearling Steers in the Feed Lot. Two Year Average.
Treatment Initial Weight Final Weight Average Daily Gain TDN Per 100 lbs. Gain Feed Cost Per 100 lbs. Gain Average Grub Count Per Hd.
Control 680 1057 2.01 623 $15.30 7.8
Co-Ral 679 1061 2.03 624 $15.35 6.1
Ruelene 677 1072 2.10 607 $14.91 3.0

 

Table 11. Effects of Systemic Grubicides on Carcass Characteristics When Used on Yearling Steers in the Feed Lot in 1963-64.
Treatment Carcass Price Per 100 Lbs. Average Carcass Grade Dressing % on Homeweight
Control $32.60 High - Good 58.8
Co-Ral $32.30 High - Good 58.8
Ruelene $32.13 High - Good 58.1

 

Table 12. Effects of Systemic Grubicides on Carcass Characteristics When Used on Yearling Steers in the Feed Lot in 1964-65.
Treatment Carcass Price Per 100 Lbs. Average Carcass Grade Dressing % on Homeweight
Control $36.68 High - Good 55.2
Co-Ral $37.12 High - Good 54.4
Ruelene $36.79 High - Good 55.1

 

Table 13. Effects of Systemic Grubicides on Carcass Characteristics When Used on Yearling Steers in the Feed Lot. Two Year Average.
Treatment Carcass Price Per 100 Lbs. Average Carcass Grade Dressing % on Homeweight
Control $34.64 High - Good 57.0
Co-Ral $34.71 High - Good 56.6
Ruelene $34.46 High - Good 56.6

 

Two methods of treatment, pour-on application and spray application, were also compared. Tables 14, 15, and 16 show the results of this comparison.

Table 14. Comparison of Pour-On Application and Spray Application of Two Systemic Grubicides Used on Yearling Steers in the Feed Lot, 1963-64.
Treatment Initial Weight Final Weight Average Daily Gain Average Grub Count Per Head
Pour-On 670 1033 2.01 3.9
Spray 664 1023 1.99 9.1

 

Table 15. Comparison of Pour-On Application and Spray Application of Two Systemic Grubicides Used on Yearling Steers in the Feed Lot, 1964-65.
Treatment Initial Weight Final Weight Average Daily Gain Average Grub Count Per Head
Pour-On 688 1120 2.21 3
Spray 688 1090 2.06 2

 

Table 16. Comparison of Pour-On Application and Spray Application of Two Systemic Grubicides Used on Yearling Steers in the Feed Lot. Two Year Average.
Treatment Initial Weight Final Weight Average Daily Gain Average Grub Count Per Head
Pour-On 679 1077 2.11 4
Spray 676 1057 2.03 6

 

Both chemical were effective in reducing grub counts. The pour-on method of application was more effective than was application by spraying. Animals treated with these chemicals produced slightly faster gains than the untreated control. In this trial the difference is so small it is not considered significant. An additional cost not included in the tables is the cost of the chemical which amounts to .40 to .50 per head plus the cost of application. Labor costs will vary depending upon many things. Therefore this item is left to the consideration of each individual operator.

The trial was hampered by a lack of grub larvae in all animals. The control of cattle lice was an added benefit observed in both lots of treated steers.


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