Comparison of phytohemagglutinin-induced cutaneous hypersensitivity reactions in the interdigital skin of broiler and layer chicks

Cutaneous basophil hypersensitivity (CBH) responses elicited by intradermal injection of phytohemagglutinin-P (PHA-P) were evaluated in the interdigital skin of broiler and layer chicks. Five- and 10-day-old broiler and layer chicks were injected intradermally in the interdigital skin between the third and fourth digits of the right foot with 25, 50, or 100 micrograms of PHA-P. The PHA-P-elicited CBH responses were evaluated by determining interdigital skin thickness before injection and 12 and 24 hr after injection. The effect of treatment with the T-lymphocyte-suppressing drug cyclosporin on the CBH responses was determined in chicks treated daily for 4 days before skin-testing at 10 days of age. Injection of PHA-P caused significant increases (P less than 0.005) in skin thickness at all dose amounts, with the maximum CBH response elicited by 100 micrograms PHA-P. The CBH response was significantly higher (P less than 0.05) in broilers than in layers. Treatment with cyclosporin significantly suppressed (P less than 0.01) the CBH response in 10-day-old chicks of both types. Results indicate that the interdigital skin-test is a rapid, simple means of assessing normal and suppressed T-lymphocyte-mediated immune response in broiler and layer chicks.     

Importance of pilus-associated antigen in Bacteroides nodosus vaccines

The performances of two cellular vaccines, one sparsely piliated and the other well piliated, were compared on irrigated pasture with those of vaccines containing their respective, purified pili. There were statistically significant differences among the four vaccines in the mean numbers of feet per sheep which developed severe foot rot during 27 weeks of exposure. The incidence of severe foot rot was significantly lower in the two pili-vaccinated groups than in the group vaccinated with well-piliated cells, which were in turn substantially more effective than the sparsely piliated. However, the two pili vaccines did not prevent infection of the interdigital skin so that the differences in vaccine performance were much less marked when interdigital skin lesions were included. The number of feet affected by blowfly strike was closely associated with the presence of the most severe lesions and consequently there were far fewer struck feet in the two pili vaccine groups than in the two cellular vaccine groups. Analysis of serum agglutinin titres led to the same assessment of vaccinal efficacy as that derived from the analysis of severe foot rot lesions. Individually the agglutinin response to vaccination was not universally associated with resistance or susceptibility to severe foot rot but mean titres were significantly higher in the two pili vaccine groups than in the highly piliated-cell vaccine group, which were all in turn significantly higher than in the poorly piliated-cell vaccine group.     

Effect of lameness on milk yield in dairy cows

OBJECTIVE: To examine the relationship between lameness and milk yield in dairy cows. DESIGN: Cohort study. ANIMALS: 531 dairy cows. PROCEDURE: Cows affected with lameness were classified into 1 of 3 groups on the basis of type of diseases or lesions observed, including interdigital phlegmon (foot rot), papillomatous digital dermatitis (foot warts), or claw lesions. Cows not affected with lameness were classified as healthy. From Dairy Herd Improvement Association records, 305-day mature equivalent milk yield data were collected at the end of lactation or when the cow left the herd. Milk yield was compared between cows affected with lameness and healthy cows. RESULTS: 167 (31%) cows were affected with lameness during lactation. Lame cows had claw lesions (60%), papillomatous digital dermatitis (31%), or interdigital phlegmon (9%). Milk yield in lame cows with interdigital phlegmon (mean, 17,122 lb) was significantly less, compared with healthy cows (19,007 lb). CONCLUSIONS AND CLINICAL RELEVANCE: In this herd, interdigital phlegmon was associated with a 10% decrease in milk production. Lame cows with claw lesions or papillomatous digital dermatitis produced less milk than healthy cows, but the difference was not significant.     

Observations on an outbreak of foot abscess in sheep

An outbreak of ovine interdigital dermatitis and foot abscess in which approximately a third of 300 Perendale ram hoggets had acute lameness was investigated. Both foot infections occurred simultaneously in the flock, and ovine interdigital dermatitis preceded the occurrence of foot abscess in seven instances. It was suggested that the behaviour pattern and sexual activity of the young rams predisposed them to ovine interdigital dermatitis and foot abscess. Although no controlled trials were conducted, the lame sheep responded well following the combined therapeutic measures of dry surroundings, formalin footbathing and selected antibiotic therapy.     

Fusobacterium necrophorum and Bacteroides melaninogenicus as etiologic agents of foot rot in cattle.

Fusobacterium necrophorum (Sphaerophorus necrophorus) and Bacteroides melaninogenicus were the predominant bacteria isolated from biopsy specimens of lesions in cattle affected with foot rot. Mixed inoculums of the 2 bacteria, applied to the scarified interdigital skin or inoculated intradermally into the interdigital skin of test cattle, induced typical lesions of foot rot. Both bacteria were reisolated in large numbers from the induced lesions.     

Interdigital skin test for evaluation of delayed hypersensitivity and cutaneous basophil hypersensitivity in young chickens

A skin test to assess T-cell mediated delayed hypersensitivity (DH) and cutaneous basophil hypersensitivity (CBH) was evaluated in the interdigital skin of young chickens. Three-day-old chickens were sensitized with Mycobacterium tuberculosis, and the DH reaction was elicited in the interdigital skin in 10-, 17-, 24-, and 31-day-old chickens by intradermal injection of tuberculin. Cutaneous basophil hypersensitivity was elicited in the interdigital skin of 10- and 14-day-old chickens by a single intradermal injection of phytohemagglutinin-P (200 micrograms). The effect of immunosuppression on the results of interdigital skin test for DH and for CBH was evaluated in chickens that were treated with dexamethasone daily for 4 days before testing. The DH reaction, as indicated by a significant (P less than 0.01) increase in the mean interdigital skin thickness, was detectable in 10-day-old chickens and was consistently evident in 17-, 24-, and 31-day-old chickens. The DH response in the interdigital skin of 24-day-old chickens was comparable with that elicited in the standard wattle test. The CBH reaction, as indicted by a significant increase (P less than 0.005) in skin thickness, was evident in the interdigital skin of 10- and 14-day-old chickens. Treatment with dexamethasone significantly decreased (P less than 0.01) the DH and CBH reactions. Results of the study indicated that the interdigital skin test may be used to evaluate normal and suppressed cell-mediated DH and CBH reactions in chickens as young as 10 and 14 days old.     

鹿源坏死梭杆菌毒力菌株FN（AB）94实验动物感染模型的建立

将坏死梭杆菌FN（AB）94分离株以10^6,10^7,10^8,10^9 个/mL等不同菌量，于耳后根颈部皮下分别接种于4组的健康实验家兔，每组3只，逐日观察感染家兔的发病情况，结果，10^8,10^9个／mL，菌量感染组家兔，在接种后9－68 d内先后死亡，68d死亡家兔的病理变化明显，并从死亡家兔内脏及脓法叶，应用触片及分离培养均检到长丝状及小杆状等形态典型的坏死梭杆菌，10^7个/mL感染家兔仅表现体重减轻，10^6个／mL感染家兔无明显临床表现，由此表明，坏死梭杆菌FN（AB）94分离株具有很强的感染毒力，对家兔的最小致死量为10^8个／mL，耳后板颈部皮下接种是适宜的感染途径，从而建立了坏死梭杆菌分离株实验动物感染模型。     

Prevalence of foot lesions in Danish Holstein cows

In a cross-sectional study of 6240 Danish Holstein cows in 55 herds using loose-housing systems, sole haemorrhages and heel horn erosions occurred frequently in almost all the herds. Digital dermatitis occurred in 47 of the 55 herds (85 per cent). Spearman correlation coefficients revealed relationships between lameness and sole ulcer (0.36), between heel horn erosion and sole haemorrhage (0.39), between heel horn erosion and interdigital dermatitis (0.29) and between sole ulcer and double sole (0.26). The prevalence of heel horn erosion, sole haemorrhage, interdigital dermatitis and digital dermatitis appeared to be most affected by herd-level factors. The associations between individual foot trimmers and all the foot lesions were statistically significant. The risk of interdigital dermatitis increased with decreasing amounts of bedding. Cows housed throughout the year had a marginally higher risk of sole haemorrhage.     

Footrot and interdigital dermatitis in sheep: farmers' practices, opinions and attitudes

In 1999, a study was initiated to improve the treatment and control of footrot and interdigital dermatitis in sheep flocks in England and Wales. In November 2000, a retrospective cross-sectional study was conducted in which 392 sheep farmers were asked to estimate the prevalence of footrot and interdigital dermatitis in their flock in the previous 12 months, whether they considered these diseases to be a problem, how they treated and controlled them and their opinion on the success of the treatment and control measures that they used; 209 of them provided usable responses. The farmers tended to be more concerned as the prevalence of the diseases increased; 91 per cent of the farmers with a prevalence of footrot of less than 5 per cent considered it a small or very small problem on their farm, but 51 per cent of the farmers with a prevalence of 5 per cent or more also considered it to be a small or very small problem. Approximately 60 per cent of the farmers who used parenteral antibiotics considered that they were good or excellent at treating footrot, and this treatment was associated with a prevalence of less than 5 per cent. A similar proportion of farmers also considered topical foot sprays and footbathing to be good or excellent for controlling footrot or interdigital dermatitis, but these treatments were not associated with a lower prevalence of footrot or interdigital dermatitis. Of the 29 farmers who used a footrot vaccine, 20 (69 per cent) considered it good to excellent and this was associated with a prevalence of footrot of less than 5 per cent in their flock; however, vaccination was not associated with lower levels of footrot across the whole sample. Farmers spent approximately 34 minutes per sheep per year treating and controlling footrot; 31 per cent were prepared to spend more money and more time to manage footrot, 27 per cent were prepared to spend more time, 19 per cent were prepared to spend more money and 23 per cent were not prepared to do either. The farmers who were willing to invest more money or more money and time had a higher prevalence of footrot.     

Associations between types of lameness and fertility

Four hundred and twenty-seven cases of first-reported foot lameness were recorded in 17 dairy herds in Somerset during the winter housing period. Lameness was classified into three categories: sole ulceration, digital disease (white line abscess, foreign bodies in the sole and pricked or punctured sole), and interdigital disease (lesions of the skin between claws and heel including foul in the foot, interdigital fibroma and dermatitis). In addition, a 'clinical effect score' was calculated to take account of the severity of lameness, the structures involved and the time for which the cows were clinically affected. The fertility records of lame cows were compared with those of the healthy cows nearest in parity and stage of lactation. In the lame cows the interval from calving to first service was four days longer, and the interval from calving to conception was 14 days longer than in the control cows, the pregnancy rate to first service was 46 per cent (controls 56 per cent), 2.14 services were required per conception (controls 1.72) and 16 per cent of lame cows were culled (controls 5 per cent). Lameness, first reported in the period 36 to 70 days after calving, was associated with a significant (P less than 0.01) increase in the interval from calving to first service of eight days; and sole ulceration, in the period 71 to 120 days after calving, was associated with an increase of 11 days (P less than 0.05). Lameness in all periods up to 120 days after calving was associated with significantly increased intervals from calving to conception (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Efficacy of amoxicillin trihydrate for the treatment of experimentally induced foot rot in cattle

Twenty holstein heifers were intradermally inoculated in the interdigital skin with a suspension containing Fusobacterium necrophorum and Bacteroides melaninogenicus to induce acute foot rot. Lesions, lameness, and swelling were evaluated during the study, using a subjective scoring system. Rectal temperature, species and number of bacteria isolated, and change in body weight were monitored throughout the study. Ten heifers (treated) were given amoxicillin trihydrate (10 mg/kg of body weight, IM) for 5 days, beginning at the onset of lameness. The remaining 10 heifers (controls) were given physiologic saline solution IM. Treated heifers had less severe lesions and greater weight gain than did control heifers. Rectal temperatures of treated heifers did not differ significantly from those of control heifers. It was concluded that administration of amoxicillin trihydrate early in the course of acute foot rot may reduce the severity of lesions associated with foot rot in cattle.     

Genetic-associated resistance to foot rot in selected Targhee sheep

Three Targhee rams obtained from the Ohio Agricultural and Experimental Station had been identified as foot rot resistant on the basis of results of challenge exposure. In the first breeding trial, when rams were bred to 20 foot rot-susceptible ewes, the percentages of foot rot-resistant offspring from the 3 foot rot-resistant rams were 68, 82, and 100, compared with 55 and 60 for foot rot-resistant offspring from 2 known foot rot-susceptible rams. In the second year, the foot rot-resistant rams were mated with ewes of unknown foot rot status. The foot rot-resistant status of their lambs was compared with that of range-raised lambs whose parents' foot rot status was unknown. During the first year, challenge exposure to the disease consisted of confinement of the lambs in moist or wet pens with sheep affected with the naturally acquired disease. This protocol was repeated for lambs born during the second-year breeding trial. In addition, the right front foot of each lamb was inoculated with a broth culture of Bacteroides nodosus. During the second year, when data that included infected feet from all lambs were analyzed, 41% of the progeny of the foot rot-resistant rams and 17% of the offspring of parents of unknown foot rot status were unaffected by the disease. When the B nodosus-inoculated foot was not included in the analysis, however, 61% of the progeny of the foot rot-resistant rams and 29% of the others were unaffected. The resistance to foot rot undoubtedly is hereditary. The mechanism of resistance may be in the interdigital skin.(ABSTRACT TRUNCATED AT 250 WORDS)     

坏死梭杆菌QL03株绵羊感染模型的建立及免疫保护性试验

坏死梭杆菌是奶牛腐蹄病的重要致病菌。用奶牛源坏死梭杆菌QL03分离株以不同浓度菌量感染绵羊蹄部,通过观察绵羊蹄部感染情况、病理变化和动物回归试验,建立了坏死梭杆菌分离株绵羊感染模型。并通过绵羊免疫保护性试验验证了绵羊作为奶牛源坏死梭杆菌QL03分离株动物模型的可行性,为进一步研究坏死梭杆菌有效的疫苗奠定实验基础。     

The incidence, cost and factors associated with foot lameness in dairy cattle in south-western Victoria

A survey of 73 dairy farms in south-western Victoria was conducted to assess the cost and mean herd incidence of foot lameness for the period from calving to the end of November, 1985, and to identify the herd, management and environmental factors associated with foot lameness. The mean herd size was 125 cows (range 82 to 220). Lameness occurred in 64 (88%) herds, and the mean herd incidence was 7.0% (range 0.0 to 30.9%). The main clinical signs associated with lameness were the presence of overworn and/or bruised soles, or stones lodged in the interdigital cleft. Factors associated with lameness were: property and herd size, age of cow, bail feeding, voluntary entry into the bails, and features of the farm track including its length, the presence of steep slopes, the type of surface material, presence and treatment of broken sections and maintenance including rolling history. The association of these factors with specific clinical signs was examined. The mean cost was estimated to be $42.90 per lame cow due to loss of production, treatment, the culling or death of lame cows, and extra man hours spent managing lame cows. It was concluded that the site, construction, maintenance and use of the farm track were of major importance to the incidence of lameness in herds in this area and recommendations for reducing lameness are made.     

Distribution of lameness lesions in beef cattle: A retrospective analysis of 745 cases

The objective of this retrospective study was to characterize the relative prevalence of diagnoses and location of lameness lesions in beef cattle. Medical records from 2005 to 2012 were reviewed and 745 cases of beef cattle that had presented for lameness were identified. Information regarding signalment, lesion location, and cause of lameness was analyzed. The cause of lameness was localized to the foot in approximately 85% of cases; a hind limb was affected over 70% of the time. The lateral claw was most commonly affected in cases of both fore- and hind-limb lameness. The most common diagnoses of noninfectious etiology were screw claw, vertical fissure, and interdigital fibroma. Infectious foot disease accounted for only 20% of foot lameness. Routine foot trimming may be warranted in some herds to improve weight-bearing balance and alleviate lameness.     

Cultural characteristics and virulence of strains of Fusobacterium necrophorum isolated from the feet of cattle and sheep

Sixty-one isolates of Fusobacterium necrophorum were recovered for study. Thirty-one were obtained from lesions of foot abscess in cattle (25) and sheep (6), 28 were from interdigital lesions in cattle and 2 were from the normal interdigital skin of cattle. The majority of isolates from lesions of foot abscess were virulent, belonged to biotype AB (Fievez 1963), produced flat, irregular shaped, greyish colonies and haemolysis on blood agar, and grew as turbid filamentous suspensions in liquid media. They produced a soluble exotoxin, a leucocidin, and were pathogenic for cattle and mice. Virulent isolates also produced a haemolysin which most readily lysed bovine, equine and chicken erythrocytes; those from sheep were less susceptible while those of rabbit and pig were the most resistant. Isolates recovered from lesions of the feet not classified as foot abscess and from clinically normal feet were predominantly of the B biotype and caused few experimental lesions, produced convex, round, yellow colonies, flocculated and sedimented while growing in liquid medium and produced little or no haemolysin or leucocidin. Routine differentiation between virulent and non-virulent bovine isolates of F. necrophorum could be achieved by assessing the colour, morphology, and degree of haemolytic activity of colonies grown on blood agar.     

Lameness in feedlot cattle.

This article examines the various causes of lameness in feedlot cattle, with an emphasis on clinical signs, treatment, and prevention. Specific conditions are discussed, including interdigital necrobacillosis, laminitis, feedlot injuries, and feedlot lameness associated with Mycoplasma bovis. Immune management of the foot is also reviewed.     

Foot lameness in dairy goats

An outbreak of foot lameness in a dairy herd of 170 goats is described. The herd, that was kept mostly indoors, was attended between December 2006 and November 2007. During this period, 15% of the goats showed lameness with foot lesions and 24% of the goats showed lameness without foot lesions. The foot lesions consisted of cracks and erosions on the horn of the bulbs of the heel that in most cases extended along the internal side of the axial hoof wall. The clinical diagnosis was interdigital dermatitis. Annual milk production was lower in lame goats compared to those that were not lame (P < 0.05). Furthermore, annual milk yield was significantly affected by the type of foot disease present and was significantly lower in cases with foot lesions than in the animals that were not lame (P < 0.05) and also in the lame goats without foot lesions (P < 0.05).     

Erythrophagocytosis in phenylhydrazine induced acute anaemia in chickens

Acute anaemia was experimentally induced in chickens with a single subcutaneous injection of phenylhydrazine-hydrochloride. The birds were necropsied at fixed intervals. Liver, spleen and red bone marrow (from middle of tibia) were promptly dissected out. Impression smears were stained and examined under dry high power. Erythrophagocytosis was massive in the liver, moderate in the spleen and less conspicuous in bone marrow. Extensive erythrophagocytosis by the mononuclear cells might be associated with extravascular haemolysis. This appeared to be a major factor in the induction of anaemia.     

Genetic Parameters of Foot and Leg Traits in Future AI Bulls: I. Influence of Age at Recording and Classifier

Information on foot and leg traits was collected on 8494 young potential future AI bulls of the three populations Danish Red, Danish Friesian and Danish Jersey by two classifiers between 1985 and 1996. Each animal was assessed at 5 and 10 months of age. The data set was used to examine the influence of age and classifier on genetic parameters of foot and leg traits by treating traits recorded at two different times or by two different people as a different characteristic in a bivariate analysis. The general incidence of foot and leg diseases was very low in young animals: only interdigital dermatitis, heel necrosis and solar bruising showed a frequency higher than 2% in 10-month-old bulls. The same traits measured on different claws yielded very high genetic correlations (r_g 0.77-0.98), suggesting that the number of measurements could be reduced. Hooves increased in size with age, and the genetic correlation between the two age classes was high (r_g 0.60-0.77). The agreement between classifiers was very high for objectively measured traits, especially for the younger age class, and interdigital dermatitis and heel necrosis, but inconclusive for the subjectively scored characteristics.