Use of Nuflor in the Treatment of Bovine Foot Rot

Introduction

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Bovine Foot Rot, also known as interdigital necrobacillosis, infectious or necrotic pododermatitis, interdigital phlegmon, foul claw, foul-in-the-foot, and super foot rot, is an infection of the foot that originates from a lesion in the area between the toes of the hoof. The infection spreads throughout the surrounding tissues, causing pain, severe lameness, fever, loss of appetite, loss of condition, and reduced milk production.

Environmental conditions, such as weather, season of year, grazing periods, and housing or pen conditions, all may have an influence on the incidence of the disease. Fusobacterium necrophorum is considered to be the major cause of foot rot. It is easily isolated from feces and soil, which helps explain why prevention and control of the disease is difficult. Other bacteria, such as Staphylococcus aureus, Escherichia coli, Actinomyces pyogenes, and Bacteroides melanogenicus, are also occasionally involved.

Foot Rot is a disease of considerable economic importance. Economic losses result from the reduction in live weight gain and the subsequent delay in marketing.

Materials and Methods:

Two studies, an induced model of foot rot and a clinical field trial, were conducted to evaluate the effectiveness of Nuflor in the treatment of foot rot. In the model study, Hereford or Hereford-cross cattle approximately 6 months of age were acclimated at the study site for 24-30 days. Only cattle in good health that were free of clinical signs of foot rot were included in the study. Cattle received an intradermal challenge of cultures of Fusobacterium necrophorum and Bacteroides melaninogenicus into the interdigital skin on day -3. Lameness and lesions were evaluated and scored by observers following treatment at day 0. Treatment groups included: Nuflor, 20 mg/kg of body weight, intramuscularly, 2 doses 48 hours apart, Nuflor, 40 mg/kg of body weight, subcutaneously, once, and sterile water dosed at the same volume and frequency as Nuflor IM.

The field study was conducted at three commercial feedlots in Nebraska. Cross-bred beef cattle less than 1 year of age with clinical signs of foot rot were eligible for inclusion in the study. Calves showing signs of lameness attributable to other disease conditions, such as traumatic foot or leg injury or arthritis, were excluded from enrollment. Lesion and lameness scores for affected feet were recorded. Treatment groups were identical to those in the model study except that sterile saline was used instead of sterile water. Treatment success or improvement was based on the degree of reduction in the observed lameness and lesion scores. Failures included those that did not meet the criteria for either success or improvement.

Results

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Tables 1 and 2 show summaries of the treatment success data for the two studies. Nuflor administered intramuscularly or subcutaneously resulted in a reduction in the severity of lameness from baseline (Day 0) to Days 2, 4, 7, and 11 and was significantly more effective than negative controls on all observation days. The two Nuflor treatment groups were statistically superior to the control groups (p<0.0001) in both studies, and there were no statistical differences between the two Nuflor treatment groups in either study.

Table 1 — Summary Statistics of Treatment Success: Model Study

N=Number of feet enrolled in the study

Day
Treatment
N
Successes
Improved
Failures
Overall
Nuflor IM
vs Control
Nuflor SC
vs Control
Nuflor SC
vs IM
7
Nuflor IM
48
39 (81%)
5 (10%)
4 ( 8%)
P<0.0001
P<0.0001
P<0.0001
P=0.389
Nuflor SC
45
35 (78%)
6 (13%)
4( 9%)
Control
45
12 (27%)
6 (13%)
27(60%)
11
Nuflor IM
48
45 (94%)
2 ( 4%)
1 ( 2%)
P<0.0001
P<0.0001
P<0.0001
P=0.262
Nuflor SC
45
40 (89%)
3 ( 7%)
2 ( 4%)
Control
45
23 (51%)
7 (16%)
15 (33%)

Table 2 — Summary of Treatment Success: Field Study, Day 7

N=Number of animals enrolled in the study

Treatment
N
Successes
Improved
Failures
Overall
Nuflor IM
vs Control
Nuflor SC
vs Control
Nuflor SC
vs IM
Nuflor IM
30
23 (77%)
1 (3%)
6 (20%)
P<0.0001
P<0.0001
P<0.0001
P=1
Nuflor SC
30
23 (77%)
1 (3%)
6 (20%)
Control
30
0 ( 0%)
1 (3%)
29(97%)

Discussion:

Bovine foot rot is an acute or chronic necrotizing infection of interdigital and coronary skin caused by a synergistic infection of Fusobacterium necrophorum and B. melaninogenicus, normal inhabitants of the bovine digestive tract. Prompt initiation of treatment is imperative for satisfactory resolution of the disease. Nuflor, administered intramuscularly or subcutaneously at the labeled dosage for treatment of respiratory disease in cattle, is effective for use in the treatment of foot rot in cattle.