The Evaluation of Nuflor® Collective Therapy and BRD Therapy in Feedlot Steers

Objective

This trial was designed to measure growth performance, carcass characteristics, field efficacy and cost-effectiveness of Nuflor (florfenicol) as collective therapy followed by Nuflor as therapy for bovine respiratory disease (BRD) in steers on feed for 180 - 200 days. Responses were compared to Nuflor as collective therapy followed by Baytril® (enrofloxacin) as BRD therapy. In addition, comparisons were made to cattle not given collective therapy and treated with Nuflor as BRD therapy.

Materials and Methods

Incoming Cattle Management

Seven hundred fifty Continental and Brahma by English cross steers were placed on test in the winter of 2001. These animals were severely stressed due to adverse weather conditions, commingling of cattle from multiple sources and other stresses such as shipping. The animals were processed upon arrival. During processing, the animals were individually identified, weighed and administered therapeutic treatments according to their specific treatment group, administered a modified live viral vaccine (Jencine® 4 vaccine) and Clostridial vaccination (Covexin® 8 vaccine), treated for internal parasites (Dectomax® antiparisiticide) and external parasites (Saber™ Pour-On insecticide) and implanted (Ralgro® implants). In addition, bulls were banded. All study animals were re-implanted with Revalor®-s implants while processing on Day 70 for collection of body weights.

Experimental Design

The experimental design was a randomized block design comprised of 3 treatments with 10 replicates (pens) per treatment. Each pen contained 25 animals for a total of 250 head per treatment and 750-head total for all 3 treatments. Animals were individually identified with a uniquely numbered eartag, but indistinguishable by treatment group. Pen riders were blinded to treatment assignments.

Treatments

Treatment Collective Therapy 1st Pull
Therapy
2nd Pull
Therapy
3rd Pull
Therapy
I Nuflor 40 mg/kg Nuflor
40 mg/kg
Naxcel®
Vetisulid®
None
II None Nuflor
40 mg/kg
Nuflor
40 mg/kg
Naxcel
Vetisulid
III Nuflor 40 mg/kg Baytril
12.5 mg/kg
Naxcel
Vetisulid
None

Collective Therapy

Steers were treated metaphylactically on arrival at the feedyard, as follows:

  1. Nuflor, 6 ml/cwt. body weight (BW), subcutaneously (SQ), to Treatments I and III
  2. Negative control, which is Treatment II, (no collective therapy given)

Bovine Respiratory Disease Treatment

Pen riders observed the animals daily for signs of acute Bovine Respiratory Disease (BRD). Animals exhibiting signs of BRD were removed from the pen for collection of rectal temperatures. Animals exhibiting acute signs of BRD with a rectal temperature 104.0 F were administered therapeutic treatment and returned to their home pen. Animals exhibiting acute signs of BRD with temperatures <104.0 F were returned to their home pen without treatment.

First time pulls in Treatment I (Nuflor/Nuflor) were administered Nuflor (40 mg/kg). Second time pulls were administered Naxcel injectable (1cc/cwt), Vetisulid injectable (5cc/cwt) and Recovr® injectable (10 cc/head) for three (3) consecutive days.

First time pulls in Treatment II (Nothing/Nuflor) were administered Nuflor (40 mg/kg). Second time pulls were administered Nuflor (40 mg/kg), and third time pulls were administered Naxcel (1 cc/cwt.), Vetisulid (5cc/cwt) and Recovr (10 cc/head) for three (3) consecutive days.

First time pulls in Treatment III (Nuflor/Baytril) were administered Baytril (12.5 mg/kg). Second time pulls were administered Naxcel (1 cc/cwt.), Vetisulid (5 cc/cwt.) and Recovr (10 cc/head) for three (3) consecutive days.

Body Weights

Individual body weights were collected on all study animals on Days 0, 30, 70 and final. Weights were full weight collected early morning prior to feeding.

Feeding Program

Cattle were managed using techniques typical for finishing steers. Steers were adapted to the final finishing diet using a series of "step-up" rations (starter, intermediate and finisher), in accordance with normal feedlot operating procedures. Cattle were fed twice (A.M. and P.M.) daily and a clean bunk management approach was followed. Feed refusals were collected and weighed back at weighdays and when needed. Feed batching was done by replicates. Each animal had ad libitum access to water via in line water tanks on a pen-by-pen basis.

Carcass Data

Carcass data, liver scores and lung lesion scores were collected on an individual animal basis

Results

Nuflor was effective collective therapy during the first 30 days (Day 0 – 30) after processing, in the face of an extreme BRD challenge, where 79% of the control (non collective therapy) animals were diagnosed with BRD. When comparing the collective therapy treatments I (Nuflor/Nuflor) and III (Nuflor/Baytril) against the non mass medicated animals (Treatment II – Nothing/Nuflor); the non mass medicated animals had significantly more first pulls (79.44% p<0.0001), second pulls (47.21% p<0.02), third pulls (47.31% p<0.0001) and deads (5 p<0.06) from Day 0 to 30.

When comparing Nuflor vs. Baytril as BRD treatments, while there were no statistically significant differences in this study, there were numerical and economic differences in many of the performance and health parameters measured. Results were: from Day 0 to 70, the Nuflor/Nuflor animals outperformed the Nuflor/Baytril animals in the following areas: gain (204.95 vs. 193.93), average daily gain (2.93 vs. 2.79), cost of gain ($0.4948 vs. $0.5104), dry consumption (15.30 vs. 15.21), dry conversion (5.23 vs. 5.45), number dead (5 vs. 7), percent mortality (2.00 vs. 2.80) and average treatment cost ($27.78 vs. $29.99).

From Day 0 to Finish, the Nuflor/Nuflor animals outperformed the Nuflor/Baytril animals in the following areas: gain (764.36 vs. 745.47), average daily gain (3.46 vs. 3.42), cost of gain ($0.4011 vs. $0.4028), dry consumption (18.67 vs. 18.37), number dead (7 vs. 13), percent mortality (2.81 vs. 5.22) and average treatment cost ($27.92 vs. $29.98). While these differences were evident, there is no guarantee that this performance can be repeated.

This trial does demonstrate that Nuflor is a cost-effective tool for collective therapy and treatment of BRD when evaluating production and health performance parameters. Nuflor used as a treatment following Nuflor used in collective therapy was very effective in treating BRD. In this study, Nuflor/Nuflor was numerically favorable in production and health results in profit centers such as gain, average daily gain, cost of gain, dry consumption, number dead, percent mortality and average treatment cost when compared to the Nuflor/Baytril animals.

Performance Summary
Day 0-30
Deads In

  Treatment 1 Treatment 2 Treatment 3
In Weight 595.37 595.44 591.67
Day 30 Weight 676.37 669.54 673.50
Gain 81.00 74.10 81.83
Average Daily Gain 2.70 2.48 2.73
Cost of Gain 69.98 66.22 71.33
Dry Consumption 14.17 13.62 14.14
Dry Conversion 5.25 5.48 5.18

Performance Summary
Day 0-70
Deads In

  Treatment 1 Treatment 2 Treatment 3
In Weight 595.37 595.44 591.88
Day 70 Weight 800.32 785.75 785.81
Gain 204.95 190.32 193.93
Average Daily Gain 2.93 2.77 2.79
Cost of Gain 49.48 48.37 51.04
Dry Consumption 15.30 15.01 15.21
Dry Conversion 5.23 5.43 5.45

Morbidity/Mortality Summary
Day 0-30

  Treatment 1 Treatment 2 Treatment 3
Number 1st Pull 132a 197b 124a
Percent 1st Pull 52.80% 79.44% 49.80%
Number 2nd Pull 48a 93b 41a
Percent 2nd Pull 36.36% 47.21% 33.06%
Number 3rd Pull 1a 44b 0a
Percent 3rd Pull 2.08% 47.31% 0.00%
Average Treatment Cost $26.45 $20.76 $28.13
Number Mortality 0a 5b,c 2a,c
Percent Mortality 0.00% 2.00% 0.80%
Values with differing superscripts (a, b, c) are different @ p0.06.

Morbidity/Mortality Summary
Day 0-70

  Treatment 1 Treatment 2 Treatment 3
Number 1st Pull 137a 198b 132a
Percent 1st Pull 54.80% 79.84% 52.80%
Number 2nd Pull 61 98 57
Percent 2nd Pull 44.53% 49.49% 43.18%
Number 3rd Pull 1a 54b 0a
Percent 3rd Pull 1.64% 55.10% 0.00%
Average Treatment Cost $27.78 $22.02 $29.99
Number Mortality 5 10 7
Percent Mortality 2.00% 4.03% 2.80%
Values with differing superscripts (a, b) are different @ p0.0001.

Performance Summary
Day 0-Finish
Deads In

  Treatment 1 Treatment 2 Treatment 3
In Weight 595.37 595.44 591.88
Finish Weight 1359.72 1317.50 1337.34
Gain 764.36 722.06 745.47
Average Daily Gain 3.46 3.33 3.42
Cost of Gain 40.11 39.70 40.28
Dry Consumption 18.67 18.14 18.37
Dry Conversion 5.40 5.44 5.37

Morbidity/Mortality Summary
Day 0-Finish

  Treatment 1 Treatment 2 Treatment 3
Number 1st Pull 137a 198b 131a
Percent 1st Pull 54.80% 79.84% 52.61%
Number 2nd Pull 63 99 58
Percent 2nd Pull 45.99% 50.00% 44.27%
Number 3rd Pull 1a 55b 0a
Percent 3rd Pull 1.59% 55.56% 0.00%
Average Treatment Cost $27.92 $22.21 $29.98
Number Mortality 7 13 13
Percent Mortality 2.81% 5.24% 5.22%
Values with differing superscripts (a, b) are different @ p0.0001.

Carcass Data Summary

  Treatment 1 Treatment 2 Treatment 3
Final Weight 1382.56 1356.74 1374.94
Carcass Weight 842.03 824.90 840.30
Dressing Percent 60.90% 60.80% 61.12%
Quality Grade 5.18 5.01 5.18
Yield Grade 3.40 3.32 3.47
% Liver Abscess 13.17% 14.47% 11.44%
% Lung Lesions 70.37% 73.62% 73.31%

©2003 Intervet Inc. All rights reserved. Saber is a trademark, and Nuflor, Jencine, Covexin, and Ralgro are registered trademarks of Intervet Inc. Dectomax is a registered trademark of Pfizer Animal Health. Baytril is a registered trademark of Bayer Animal Health. Naxcel is a registered trademark of Pharmacia. Vetisulid and Recovr are registered trademarks of Fort Dodge Animal Health.