Evaluation of a screening programme for identification of mannosidosis heterozygotes in angus cattle

Sir, — In recent years, much research effort has been directed towards identifying the cause of Ryegrass staggers (RGS). Many promising leads have been investigated, including studies of fungi in soil, ryegrass leaves, and dead leaf litter that could produce tremorgenic mycotoxins⁽³⁾. Several groups of fungi produce tremorgens⁽⁴⁾ which, when injected into sheep, produce symptoms similar to those in field outbreaks of RGS. However, under field conditions, populations of these fungi have not been shown to differ significantly between toxic and non-toxic pasture⁽⁷⁾ (McKenzie &; Byford, unpublished data).     

Investigation of a cutaneous delayed hypersensitivity response as a means of detecting Salmonella dublin infection in cattle

Delayed hypersensitivity reactions developed 48 to 96 h after intradermal injection of killed Salmonella dublin in 25 of 28 cattle which had been inoculated intravenously, and in five of 10 cattle which had been inoculated orally with S dublin 24 to 493 days previously. Control animals showed no delayed hypersensitivity reactions. Persistence of infection in five of the intravenously inoculated and in four of the orally inoculated animals was confirmed by isolation of S dublin from the carcases at necropsy one week after skin testing. Failure to isolate the organism from the carcases of 21 animals which had reacted positively to the intradermal test did not eliminate the possibility of their being carriers of S dublin. Skin testing was concluded to be a reliable means of identifying animals which had been, and possibly still were, infected systemically with S dublin. However recovered animals might be falsely identified as infected. Repeated testing gave misleading results.     

Plasma prolidase activity as a possible diagnostic index of chronic hepatic abscess in cattle

The usefulness of prolidase as a biochemical parameter to represent the chronic state of hepatic abscess was discussed in eight cattle experimentally inoculated with Fusobacterium necrophorum and 18 spontaneously affected cattle. Blood was daily collected to measure the plasma prolidase activity and sialic acid level from the experimental cattle for 90 days after inoculation. In three out of four cattle affected with hepatic abscess, prolidase activity began to rise about 40 days after inoculation, and maintained high activity till 90 days. In the same cattle the sialic acid concentration increased from 7 to 10 days after inoculation, and gradually returned to the normal value 50 days after it. Another cow showed a similar change in early stage of experiment, but prolidase activity decreased after 70 days and sialic acid concentration maintained high level till 90 days. In two cattle, which showed scars but no abscess on autopsy, the prolidase activity increased temporarily from 40 to 55 days after inoculation. In the control cattle inoculated with an inactivated bacterial suspension, neither the sialic acid level nor the prolidase activity showed any large variation in the experimental period. Among the spontaneously affected cattle, those with a high sialic acid level revealed normal prolidase activity and those with a normal sialic acid level had high prolidase activity.     

Vaccination as a possible means of preventing lantana poisoning

The toxic triterpene acids lantadene A and lantadene B were isolated from Lantana camara and conjugated to bovine serum albumen or haemocyanin. The conjugates were emulsified with complete Freund's adjuvant and injected into sheep and cattle. Vaccinated animals produced antibodies against the toxic compounds. Cholestasis was less severe in vaccinated than in non-vaccinated sheep challenged with a toxic dose of lantana. The results indicated a mild protective effect of vaccination against the hepatotoxic effects of lantana toxins.     

Plasma pyruvate kinase activity vs creatine kinase activity as an indicator of the porcine stress syndrome

Plasma pyruvate kinase (PK) and creatine kinase (CK) activities were increased significantly (P less than 0.001 and P less than 0.05, respectively) in homozygote halothane-reacting pigs (nn), compared with those activities in homozygote nonreacting pigs (NN). Pyruvate kinase activity was less variable within groups than was CK activity, allowing more effective discrimination between nn and NN geno-types. The PK and CK activities in plasma increase with age in halothane-reacting pigs and the nonreacting pigs. Enzyme activities in heterozygote (Nn) nonreacting pigs did not differ significantly (P greater than 0.05) from enzyme activities of homozygote (NN) nonreacting pigs. Although PK was better than CK in identifying stress-susceptible pigs, age-related effects and the failure to identify heterozygotes may restrict the use of plasma PK activity as a diagnostic test for the stress syndrome.     

Saliva crystallisation as a means of determining optimal mating time in bitches

Objectives : To chart saliva crystallisation patterns throughout pro-oestrus and oestrus in bitches, and to assess their reliability as a tool for optimising the timing of breeding. Methods : Six beagle bitches with normal reproductive activity were used. Saliva ferning patterns were established during pro-oestrus and oestrus. Vaginal cytology, progesterone (P4) levels and behavioural signs were used to determine the optimum mating time. Receiver operating characteristic (ROC) analysis was performed. Results : Different ferning patterns were scored from 0 to 2. Although variations in saliva crystallisation were noted during the follicular phase of the oestrous cycle in bitches, the test did not prove accurate; test sensitivity was 40·6%, i.e. too low to reliably discriminate the fertile period, while specificity was 86·1%. Clinical Significance : This test could be used to complement other methods of determining the fertile period in bitches, but its potential capacity remains to be demonstrated.     

Relative efficiency of techniques for detecting avian reticuloendotheliosis virus as a vaccine contaminant

Three techniques were compared for sensitivity in detecting reticuloendotheliosis virus (REV) in a deliberately contaminated Marek's disease vaccine. The most sensitive and rapid test was the indirect fluorescent antibody test (FAT). The indirect immunoperoxidase test, although simple to perform and only marginally less sensitive than the FAT, was difficult to interpret at low levels of REV. Using immunoelectron microscopy, virions were seen only after three subcultures and then not to the same level as that detected by the FAT or immunoperoxidase test. Serum raised against the HPRS-1 strain of REV detected other strains of this virus in the FAT.     

A study of the pharmacokinetics and thromboxane inhibitory activity of a single intramuscular dose of carprofen as a means to establish its potential use as an analgesic drug in white rhinoceros

The alleviation of pain and prevention of suffering are key aspects of animal welfare. Unfortunately, analgesic drugs are not available for all species. White rhinoceros (Ceratotherium simum ), representing one of such species, which survive poaching attempts inflicted with severe facial injuries and gunshot wounds, nonetheless require analgesic support. To improve treatment conditions, this study explored the use of carprofen for the treatment of pain and inflammation in white rhinoceros. The pharmacokinetics of 1 mg/kg intramuscular carprofen was evaluated in six healthy white rhinoceros. The half‐life of λ_z and mean residence time was 105.71 ± 15.67 and 155.01 ± 22.46 hr, respectively. The area under the curve and the maximum carprofen concentration were 904.61 ± 110.78 μg ml^?1 hr^?1 and 5.77 ± 0.63 μg/ml, respectively. Plasma TXB ₂ inhibition demonstrated anti‐inflammatory properties and indicated that carprofen may be effective for a minimum of 48 hr in most animals. With its long half‐life further indicating that a single dose could be effective for several days, we suggest that carprofen may be a useful drug for the treatment of white rhinoceros.     

Veterinary school consortia as a means of promoting the food-supply veterinary medicine pipeline

Ideas about centers of emphasis and veterinary medical teaching consortia have resurfaced to attract students into food-supply veterinary medicine (FSVM). From 1988 to 2000 a multiple veterinary school consortium approach to food-animal production medicine (FAPM) teaching was conducted to handle regional differences in case load, faculty strengths, and student interests. Six universities developed a memorandum of understanding to provide a wide variety of in-depth, species-specific clinical experiences in FAPM to balance their individual strengths and weakness in addressing food-animal agriculture, to provide for student exchange and faculty development, and to conduct research in food safety. Changes in leadership, redirection of funds, failure to publicize the program to faculty and students, and a focus on research as opposed to teaching led to dissolution of the consortium. However, this approach could work to improve recruitment and retention of students in FSVM if it focused on student exchange, fostered a more integrated curriculum across schools, encouraged faculty involvement, garnered institutional support, and used modern technology in teaching. Private veterinary practices as well as public/corporate practices could be integrated into a broader food-animal curriculum directed at building competency among FSVM students by providing the in-depth training they require. Requirements for the success of this type of program will include funding, marketing, leadership, communication, coordination, integration, and dedicated people with the time to make it work.     

Benefit-cost analysis of vaccination and preemptive slaughter as a means of eradicating foot-and-mouth disease

OBJECTIVE: To assess relative costs and benefits of vaccination and preemptive herd slaughter to control transmission of foot-and-mouth disease (FMD) virus (FMDV). SAMPLE POPULATION: 2,238 herds and 5 sale yards located in Fresno, Kings, and Tulare counties of California. PROCEDURE: Direct costs associated with indemnity, slaughter, cleaning and disinfecting livestock premises, and vaccination were compared for various eradication strategies. Additional cost, total program cost, net benefit, and benefit-cost value (B/C) for each supplemental strategy were estimated, based in part on results of published model simulations for FMD. Sensitivity analyses were conducted. RESULTS: Mean herd indemnity payments were estimated to be dollars 2.6 million and dollars 110,359 for dairy and nondairy herds, respectively. Cost to clean and disinfect livestock premises ranged from dollars 18,062 to dollars 60,205. Mean vaccination cost was dollars 2,960/herd. Total eradication cost ranged from dollars 61 million to dollars 551 million. All supplemental strategies involving use of vaccination were economically efficient (B/C range, 5.0 to 10.1) and feasible, whereas supplemental strategies involving use of slaughter programs were not economically efficient (B-C, 0.05 to 0.8) or feasible. CONCLUSIONS AND CLINICAL RELEVANCE: Vaccination with a highly efficacious vaccine may be a cost-effective strategy for control of FMD if vaccinated animals are not subsequently slaughtered and there is no future adverse economic impact, such as trade restrictions. Although less preferable than the baseline eradication program, selective slaughter of highest-risk herds was preferable to other preemptive slaughter strategies. However, indirect costs can be expected to contribute substantially more than direct costs to the total cost of eradication programs.     

Plasma disappearance of creatinine as a renal function test in the dog

The serum concentration of creatinine at 120 minutes (SC120) after intravenous injection of 88 mg kg-1 of creatinine, the plasma half-life (t1/2) and the plasma clearance of creatinine (PCC) were evaluated as renal function tests in 30 healthy adult dogs and six adult dogs with known or suspected renal disease. The mean SC120 in the normal dog was 0.31 +/- 0.08 mmol litre-1 and in the clinical cases 0.71 +/- 0.19 mmol litre-1. The correlation coefficients between SC120 and renal creatinine clearance (RCC) for the normal dogs and the clinical cases were -0.76 and -0.69, respectively. At 120 minutes after injection, 95 per cent of normal dogs would be predicted to have a serum creatinine concentration below 0.46 mmol litre-1. The mean plasma t1/2 of creatinine for the normal dogs was 107.7 +/- 17.96 minutes, while the clinical cases had a wide range of values (148.8 to 620.1 minutes). Plasma t1/2 of creatinine was correlated with RCC for both the normal dogs and the clinical cases (r = -0.55, r = -0.91, respectively). The mean PCC for the normal dogs was 7.42 +/- 2.22 ml min-1 kg-1 (range 4.95 to 13.28 ml min-1 kg-1). There was a good correlation between RCC and PCC (r = 0.7). The PCC for the clinical cases ranged from 0.76 to 3.37 ml min-1 kg-1. The correlation between RCC and PCC was significant (r = 0.91). Thus SC120, t1/2 and PCC may be useful methods of assessing renal function in dogs with renal impairment insufficient to cause azotaemia.     

Staphylococcosis of turkeys. 3. Bacterial interference as a possible means of control

Two Staphylococcus epidermidis isolates from turkeys were used as interfering agents to help control staphylococcosis. Both isolates adhered to tissues of the turkeys' respiratory tract, interfered with attachment of virulent S. aureus, produced bacteriocins bacteriocidal to S. aureus, and were avirulent for turkeys. About 200,000 turkeys in commercial flocks were exposed to aerosols of these interfering isolates between 1 and 6 weeks of age, and many became colonized with these bacteria. The aerosol-treated turkeys had lower levels of colonization with S. aureus and had a 3% higher gross survival rate than untreated control turkeys.     

A trial of biosecurity as a means to control Campylobacter infection of broiler chickens

We ran a controlled intervention trial to assess whether the risk of a broiler flock becoming infected with Campylobacter could be reduced by biosecurity measures. These were a standard method of cleansing and disinfecting the poultry house prior to stocking, and a standard hygiene protocol followed by all personnel who entered the study house during the flock's life. Thirty-nine flocks were allocated to intervention or control groups in a ratio of 1:2. Intervention flocks were asked to follow the specified biosecurity measures; all flocks were monitored weekly for Campylobacter infection. Analysis of infection at 42 days of age and over the life of the flock showed that the risk of thermophilic Campylobacter infection of broilers was reduced by over 50% in intervention flocks. Parts of the intervention identified as significant in the univariable analysis included twice weekly replenishment of boot dip disinfectant; potential independent risk factors identified included the location of ventilation fans and daily sanitisation of the water supply. The non-random allocation of 10 flocks to the control group may have introduced some study bias (the effect of which is discussed in the paper).     

豆粕中尿素酶活性检测方法的应用推广

<正>豆粕的加工过程是影响豆粕质量的关键,加热过程可使蛋白质适度变性,使大部分热不稳定抗营养因子钝化和失活,消除抗营养因子对动物的危害,提高氨基酸消化率,因此加热程度是影响豆粕品质的重要因素。     

Investigation of the gamma-check-c test as a means of evaluating IgG levels in equine colostrum

One hundred and seventy-eight colostrum samples from 90 mares were evaluated for adequate IgG content (≥ 3800 mg/dl) using the GAMMA-CHECK-C test. A positive test is based on the ability of glutaraldehyde to react with gammaglobulin to form a solid clot. When the GAMMA-CHECK-C test was compared to colostral IgG values of ≥ or < 3800 mg/dl obtained by radial immunodiffusion and to a colostral specific gravity of ≥ or < 1.060 as measured by a colostrometer, the positive predictive value was 100% and 98.2% and the negative predictive value 88.9% and 95.7%, respectively. In this population of mares 11/80 had pre-suckle colostral IgG levels of < 3800 mg/dl. Three foals suckling colostrum positive to the GAMMA-CHECK-C test (IgG ≥ 3800 mg/dl) showed high levels of IgG as early as 3 hr post-suckle (740, 810 and 1400 mg/dl). One foal suckling colostrum negative to the GAMMA-CHECK-C test, who received no supplemental colostrum, had an IgG < 400 mg/dl at 24 hr of age. GAMMA-CHECK-C is a quick, easy and economical field test for the semi-quantitative determination of colostral IgG.     

Presuturing as a means of reducing skin tension in excisional biopsy wounds in four horses

Excisional biopsy of a skin lesion was performed in 4 horses after stretching the surrounding skin with mattress sutures. The technique of presuturing allowed all biopsy wounds to be closed without excessive tension on the suture lines.