Drug Residues In Animal Products Research Articles

Reducing Veterinary Drug Residues in Animal Products: A Review.

A survey we conducted suggests that the ingestion of veterinary drug residues in edible animal parts constitutes a potential health hazard for its consumers, including, specifically, the possibility of developing multidrug resistance, carcinogenicity, and disruption of intestinal normal microflora. The survey results indicated that antibiotics, parasitic drugs, anticoccidial, or nonsteroidal anti-inflammatory drugs (NSAIDs) are broadly used, and this use in livestock is associated with the appearance of residues in various animal products such as milk, meat, and eggs. We observed that different cooking procedures, heating temperatures, storage times, fermentation, and pH have the potential to decrease drug residues in animal products. Several studies have reported the use of thermal treatments and sterilization to decrease the quantity of antibiotics such as tetracycline, oxytetracycline, macrolides, and sulfonamides, in animal products. Fermentation treatments also decreased levels of penicillin and pesticides such as dimethoate, malathion, Dichlorodiphenyldichloroethylene, and lindane. pH, known to influence decreases in cloxacillin and oxacillin levels, reportedly enhanced the dissolution of antimicrobial drug residues. Pressure cooking also reduced aldrin, dieldrin, and endosulfan in animal products. Therefore, this review provides updated information on the control of drug residues in animal products, which is of significance to veterinarians, livestock producers, and consumer health.

A Pipetting Sample Preparation with Water Eluent followed by Water Mobile Phase HPLC-DAD Analysis for Residual Monitoring of Sulfadimidine in Milk

<p>While it is certain that various veterinary drugs used for the prevention and treatment of livestock animal diseases contribute to the stable production of animal products in recent years, on the other hand, the overuse or misuse of these drugs is of great concern because it can result in their presence in animal-derived foods for human consumption.To assure the safety of animal-derived foods for the consumer, Codex Aliamentarius sets maximum residue limits (MRLs) for veterinary drugs. Because determinations for veterinary drugs in the animal-derived foods are therefore an important specific activity to guarantee food safety, the validated analytical method for the determining target drugs are presently required.</p><p>In answer to the present expansion and diversification in the international animal product trade, the development of international harmonized analytical methods (= universal standard methods) to determine veterinary drug residues in animal products is essential to guarantee equitable international trade in these foods and ensure food safety for consumers. Without regard for industrial nations and developing countries, the optimal harmonized analytical method for residue monitoring in foods must be quick, easy, reliable, inexpensive, and capable of quantifying residues at concentrations less than the target drug’s MRL in animal products and must cause no harm to the environment and analyst.</p><p>Although several methods have been described in the literature for quantifying veterinary drugs in foods, these methods have three crucial drawbacks as follows: 1) the sample preparation operations are complicated and labor intensive, which are time-and cost-consuming, do not permit the determination of large number of samples, and can give low reproducibility; 2) organic solvents are used as extraction solvents, purification eluent, and/or as LC mobile phases without fail -Risk associated with these solvents extend beyond direct implications for the health of humans and wildlife to affect our environment and the ecosystem in which we all reside. Eliminating the use of organic solvents is an important goal in terms of environmental conservation, human health and the economy; 3)the detections/identifications are based on LC-MS or -MS/MS - The facilities that LC-MS/MS system is available are limited to part of industrial nations because these are hugely expensive, and the methodologies use complex and specific. These are unavailable in a lot of laboratories for routine analysis, particularly in developing countries. No optimal method that satisfies the aforementioned requirements has yet been identified.</p>As an optimal technique that can be recommended as an international harmonized analytical method for the routine residue monitoring in animal-derived foods, this paper describes a quick, easy, and small-scale sample preparation followed by an isocratic water mobile phase HPLC method for determining sulfadimidine (SDD) in cow’s milk under no-use organic solvent conditions. The SDD selected here is one of the most frequently used veterinary drugs worldwide, and has only the Codex’s MRL (0.0025 μg/mL for SDD in milk) set for several kinds of sulfonamides.Cow’s milk contains a good balance of protein, fat, and carbohydrate, is an indispensable food because it is inexpensive and readily available.

Organik Hayvansal Üretimde Bitkisel Drogların Kullanılması: Orta Anadolu Bölgesi Halk Veteriner Hekimliği Örneği

Organik hayvansal üretim, hayvanların fizyolojik ihtiyaçlarına uygun bakım ve besleme yöntemlerinin uygulandığı, gerektiğinde alternatif ilaç ve tedaviye öncelik verilerek hayvan sağlığının korunduğu doğal bir yetiştirme sistemidir. Hayvan yetiştiriciliğinde kullanılan antibiyotik ve antiparaziter ilaçlara karşı dirençli suşların giderek artması, hayvansal ürünlerde ilaç kalıntılarının meydana gelmesi ve bu ürünleri tüketen insanlarda önemli sağlık problemlerine yol açması alternatif bitkisel çözüm arayışlarını beraberinde getirmiştir. Bu çalışmada, Orta Anadolu Bölgesi halk veteriner hekimliği özelinde kullanılan bitkisel drogların organik hayvansal üretimde tedavi ve koruyucu etkilerinin değerlendirilmesi amaçlandı. Çalışmanın materyalini, Orta Anadolu Bölgesi‘ndeki (Çankırı, Kayseri, Kırıkkale, Kırşehir, Yozgat) hayvan yetiştiricilerinden elde edilen yazılı, sözlü ve görsel veriler oluşturdu. Çalışmada, sığır, koyun, at, tavuk, arı ve köpek türlerinde görülen iç hastalıkları, cerrahi hastalıklar, doğum ve jinekolojik sorunlar ve paraziter hastalıklarda tedavi amacıyla 30 bitkisel drogun kullanıldığı tespit edildi. Organik hayvancılıkta başta antibiyotikler olmak üzere her türlü sentetik ilaç kullanımının yasaklandığı ya da sınırlandığı değerlendirildiğinde, sürü sağlığının korunması ve tedavisinde bu maddelerin yerine doğal olan bitkisel drogların tercih edilmesinin olumlu katkılar sağlayacağı ileri sürülebilir.

Organik Hayvansal Üretimde Bitkisel Drogların Kullanılması: Orta Anadolu Bölgesi Halk Veteriner Hekimliği Örneği

Organic animal production is a natural breeding system in which animal health is protected by giving priority to alternative medicines and treatment as needed by applying appropriate management and feeding methods based on the physiological requirements of animals. Increasing numbers of strains resistant to antibiotics and antiparasitic drugs used in animal breeding have brought about the search for alternative herbal remedies that lead to drug residues in animal products and lead to important health problems in people consuming these products. In this study, it was aimed to evaluate the therapeutic and protective effects of herbal drugs used in organic animal production in ethnoveterinary medicine in the Central Anatolia Region. The material of the study collected as written and declared facts as well as visual data were obtained from animal breeders in the Central Anatolia Region. The results indicated that 30 herbal drugs were used for the treatment of internal diseases, surgical diseases, obstetric and gynecological problems and parasitic diseases in cattle, sheep, horse, poultry, bee, and dog species. Based on the evaluation of the facts that the use of all kinds of synthetic drugs, especially antibiotics, is prohibited or restricted in organic livestock, it can be said that natural herbal drugs instead of artificial substances will provide positive contributions in the protection and treatment of herd health.

Organik Hayvansal Üretimde Bitkisel Drogların Kullanılması: Orta Anadolu Bölgesi Halk Veteriner Hekimliği Örneği

Organic animal production is a natural breeding system in which animal health is protected by giving priority to alternative medicines and treatment as needed by applying appropriate management and feeding methods based on the physiological requirements of animals. Increasing numbers of strains resistant to antibiotics and antiparasitic drugs used in animal breeding have brought about the search for alternative herbal remedies that lead to drug residues in animal products and lead to important health problems in people consuming these products. In this study, it was aimed to evaluate the therapeutic and protective effects of herbal drugs used in organic animal production in ethnoveterinary medicine in the Central Anatolia Region. The material of the study collected as written and declared facts as well as visual data were obtained from animal breeders in the Central Anatolia Region. The results indicated that 30 herbal drugs were used for the treatment of internal diseases, surgical diseases, obstetric and gynecological problems and parasitic diseases in cattle, sheep, horse, poultry, bee, and dog species. Based on the evaluation of the facts that the use of all kinds of synthetic drugs, especially antibiotics, is prohibited or restricted in organic livestock, it can be said that natural herbal drugs instead of artificial substances will provide positive contributions in the protection and treatment of herd health.

Anthelmintic Activities of Aqueous and Methanol Extracts of Prunella vulgaris L.

The increasing anthelmintic resistance, drug residues in animal products and high cost of conventional anthelmintics has created an interest in studying medicinal plants as an alternative source of anthelmintics. The aqueous and methanolic extracts of Prunella vulgaris was evaluated for anthelmintic efficacy against gastrointestinal nematodes of sheep under both in vitro and in vivo conditions using worm motility inhibition assay, egg hatch assay and faecal egg count reduction percent (FECR%) assay respectively. Crude methanol extract and crude aqueous extract of P. vulgaris resulted in mean percentage mortality of 94.44%, as observed after the worms were put in lukewarm PBS for 30 min after exposure to different treatments(p<0.01). Crude methanol extract (LC50=2.48 mg/mL) had higher inhibitory effects compared to that of crude aqueous extract (LC50=3.36 mg/mL) on egg hatching, exhibiting higher ovicidal activity. in vivo, maximum reduction (92.86%) in faecal egg counts was recorded for crude methanol extract, followed by crude aqueous extract (80.34%) with dose 2 g/kg of body weight at day 15 post-treatment. The results of the present study suggest that P. vulgaris extracts are promising alternatives to the commercially available anthelmintics for the treatment of sheep nematodes.

Development of Analytical Method and Monitoring of Veterinary Drug Residues in Korean Animal Products

This study was conducted to determine the residual amount of veterinary drugs such as meloxicam, flunixin, and tulathromycin in animal products (beef, pork, horsemeat, and milk). Veterinary drugs have been widely used in the rearing of livestock to prevent and treat diseases. A total of 152 samples were purchased from markets located in major Korean cities (Seoul, Busan, Incheon, Daegu, Daejeon, Gwangju, Ulsan and Jeju), including Jeju. Veterinary drugs were analyzed by liquid chromatography-tandem mass spectrometry according to the Korean Food Standards Code. The resulting data, which are located within 70-120% of recovery range and less than 20% of relative standard deviations, are in compliance with the criteria of CODEX. A total of five veterinary drugs were detected in 152 samples, giving a detection rate of approximately 3.3%; and no food source violated the guideline values. Our result indicated that most of the veterinary drug residues in animal products were below the maximum residue limits specified in Korea.

Anthelmintic activity of Indigofera tinctoria against gastrointestinal nematodes of sheep.

Aim:Gastrointestinal (GI) nematodes are considered as a major constraint for successful sheep production. Control of these parasites heavily relies on the use of chemical anthelmintics. Over the past decades, the development of anthelmintic resistance to various groups of anthelmintics and problem of drug residues in animal products has awakened interest in medicinal plants as an alternative source of anthelmintics. Hence, this study was undertaken to evaluate the anthelmintic efficacy of Indigofera tinctoria by scientifically validated in vitro and in vivo tests approved by the World Association for the Advancement of Veterinary Parasitology.Materials and Methods:In vitro assays such as egg hatch assay for ovicidal and larval migration inhibition and larval development assay for larvicidal properties were used to investigate in vitro effect of extracts on strongyle egg and larvae, respectively. Fecal egg count reduction test was conducted in vivo to evaluate the therapeutic efficacy of the extracts administered orally at dose rates of 125, 250, 500 mg/kg to sheep naturally infected with mixed GI nematodes.Results:Ethanolic extract of I. tinctoria demonstrated significant (p<0.01) inhibition on egg hatching at concentrations of 40 mg/ml and 80 mg/ml. In in vivo assay, the ethanolic extract of I. tinctoria reduced the fecal egg count ranging between 30.82% and 47.78% at various doses (125, 250 and 500 mg/kg). Although there was a slight variation, all the hematological parameters were within the normal range reported for sheep. Except for alanine transaminase, the overall mean of all the serum biochemical profile was within the normal range for sheep.Conclusion:Based on the results obtained by in vitro and in vivo assay, the ethanolic extract of I. tinctoria possesses anthelmintic activity and could replace the chemical anthelmintics used presently.

Chicken egg yolk antibodies (IgY) as non-antibiotic production enhancers for use in swine production: a review.

In recent years, the use of in-feed antibiotics for growth and disease prevention in livestock production has been under severe scrutiny. The use and misuse of in-feed antibiotics has led to problems with drug residues in animal products and increased bacterial resistance. Chicken egg yolk antibodies (IgY) have attracted considerable attention as an alternative to antibiotics to maintain swine health and performance. Oral administration of IgY possesses many advantages over mammalian IgG such as cost-effectiveness, convenience and high yield. This review presents an overview of the potential to use IgY immunotherapy for the prevention and treatment of swine diarrhea diseases and speculates on the future of IgY technology. Included are a review of the potential applications of IgY in the control of enteric infections of either bacterial or viral origin such as enterotoxigenic Escherichia coli, Salmonella spp., rotavirus, porcine transmissible gastroenteritis virus, and porcine epidemic diarrhea virus. Some potential obstacles to the adoption of IgY technology are also discussed.

Residues of synthetic hormones in pork, Madagascar

In Madagascar, little information is available on drug residues in animal products. Official veterinary services have been recently informed about the misuse of human injectable contraceptives in pig farms. Farmers and local animal health workers have been suspected of treating pigs for growth promotion and of using human progestins, especially medroxyprogesterone acetate (MPA), as a chemical alternative method for castration of sows that are then fattened before culling. Indeed, MPA may arrest the onset of farrowing and induce post-lactational anestrus in sows.Because the use of synthetic hormones in pig husbandry is consid­ered a fraud by the Malagasy legislation, an exploratory study was carried out to confirm these suspicions and investigate the main molecules concerned.We investigated 80 pigs slaughtered in seven Malagasy abattoirs and raised in eight (out of 22) Malagasy regions (i) to confirm the contamination of carcasses by anabolic hormones by liquid chromatography coupled to mass spectrometry (LC-MS/MS), (ii) to identify the concerned molecules, and (iii) to explore consumers’ exposure to hormone residues. Only adult sows were sampled con­sidering that chemical castration with progestogens was the most common hypothesis of misuse of synthetic hormones in the field.The screening of the 80 kidney-fat samples did not reveal residues of progestogens other than MPA. MPA-positive samples were detected in 10 out of 15 districts (66.7%), and in all eight surveyed regions except one (87.5%), Diana Region in Northern Madagascar. Our results revealed heavy contamination of pork products by synthetic hormone residues; its prevalence was high considering that such residues are not supposed to occur accord­ing to the Malagasy legislation. Investigations by Malagasy vet­erinary services revealed that farmers and animal health workers purchased syringes of progestogens (Confiance™, Pfizer). These low-price progestins are easily available in private local dispen­saries and basic health centers (public sector).Without any control, farmers can easily administer MPA to pigs. It has thus become urgent to launch public-awareness campaigns and improve control within the sectors of animal production and public health over the entire country.

Surveillance of veterinary drug residues in pork meat in Madagascar

Antibiotics are used in animal feeds as growth promoters or for disease prevention and treatment. Drugs and their metabolites accumulate into body cells and constitute the so-called drug residues. Residual antimicrobials in food are an increasing risk for human health. Antibiotic residues in meat and other foods are suspected to be responsible for drug allergies and emergence of antimicrobial-resistant bacteria.In Madagascar, bacterial resistance against several antibiotics has been regularly observed in pathogens isolated from humans and pigs. Suspicion of drug misuse in farms has been frequently recorded by animal health professionals but no guidelines are available on the good usage of antibiotics in livestock. Since scarce information is available on antimicrobial residues in ani­mal products in Madagascar, this study aimed at determining the prevalence of pork meat contaminated by such residues and sold in Antananarivo markets.A total of 967 meat samples (diaphragm muscle) were collected during 2010 and 2011 in the four main abattoirs of Antananarivo, and in three additional regional abattoirs, i.e. Antsirabe, Mahitsy (Central Madagascar) and Tsiroamandidy (Western Madagascar). Analysis for antimicrobial detection in meat was performed with the commercial Premi®-test kit (DSM, Urmond, Netherlands) at the National Veterinary Diagnostic Laboratory in Antananarivo. Premi®-test is a broad spectrum microbial screening test for the detection of antibiotic and sulfonamide residues in meat or meat products at, or below maximum residue limit (MRL) levels. MRL is the maximum concentration of residues following administration of a veterinary medicine which is legally permit­ted or acceptable in food under European Union legislation. The Premi®-test kit contains a standardized number of spores of Bacillus stearothermophilus, very sensitive to many antibiotics and sulfa compounds, in agar medium with selected nutrients together with an indicator. Premi®-test is based on the inhibi­tion of the growth of B. stearothermophilus. When meat juice is added to the Premi®-test ampoule and heated at 64°C, spores germinate. The germinated spores multiply and form an acid when no inhibitory substances are present, leading to an indica­tor color change from purple to yellow. When antimicrobial mol­ecules are present above the detection level, no growth occurs and the color remains purple.Table I presents the results of the percentage of positive samples in the various regions of Madagascar. On average 37.2% sam­ples were contaminated by antimicrobial residues. A significant increase from 32 to 39% was observed between 2010 and 2011, respectively. No significant differences were found between samples according to sex, breed or age class in individual ani­mals. No differences between pig farm origins were found either (Figure 1). However, Amoron’i Mania Region, and particularly suburban Ambositra, was the most contaminated area in 2010 (67%; n = 9) and Melaky region (Western Madagascar) in 2011. Pork meat samples originating from the same production area were less contaminated by drug residues when the animals were slaughtered in urban abattoirs compared to provincial abat­toirs. In this first step toward a national surveillance system, we confirm that drug residues in animal products are a serious public health concern for Madagascar.

Residues of medroxyprogesterone acetate detected in sows at a slaughterhouse, Madagascar

In Madagascar, little information about drug residues in animal products is available. However, recently, official veterinary services were informed about the misuse of human injectable contraceptives in pig farms as an alternative for chirurgical castration of adult sows before culling. We investigated pigs (n = 80) slaughtered in 7 Malagasy abattoirs and raised in 8 of the 22 Malagasy regions (1) to confirm the contamination of carcasses by anabolic hormones by using LC-MS/MS, (2) to identify the substances of concern and (3) to explore the consumers’ exposure to hormone residues. Medroxyprogesterone acetate was the only synthetic hormone detected in kidney fat. Samples positive with medroxyprogesterone acetate were observed in 66.7% of the districts investigated and in 87.5% of the surveyed regions, confirming its large misuse in livestock. Public awareness campaigns and control improvement among the animal production sector and among the Malagasy public health sector are therefore urgent.

Thymus capitatus from Tunisian arid zone: Chemical composition and in vitro anthelmintic effects on Haemonchus contortus

The increasing prevalence of anthelmintic resistant strains of helminths, the drug residues in animal products and the high cost of conventional anthelmintics has created an interest in studying medicinal plants as an alternative source of anthelmintics. Thymus capitatus (Lamiales: Lamiaceae) is used traditionally by people as spices and reported to possess some biological effects. The objective of this study is to evaluate the anthelmintic efficacy of T. capitatus in comparison to albendazole against the gastrointestinal nematodes of sheep. To fulfil the objectives, in vitro anthelmintic activities of crude aqueous and crude ethanolic extracts of aerial parts of T. capitatus were investigated on the eggs and adults of the nematode parasite Haemonchus contortus. Both extract types of T. capitatus completely inhibited egg hatching at a concentration close to 2mg/ml. LC50 of ethanolic extract of T. capitatus was 0.368mg/ml while that of aqueous extract was 6.344mg/ml (p<0.05). The ethanolic extract showed higher in vitro activity against adult parasites than the aqueous one in terms of the paralysis and/or death of the worms at different hours post-treatment. Dose dependent effect was observed for both extracts. Chemical analyses revealed that the overall profile of both extracts was dominated by oxygenated constituents. In addition, ethanolic extract is mainly composed of phenols among which thymol (71.22%) and camphor (17.18%).As far as the literature could be ascertained, this is the first publication on anthelmintic activity of T. capitatus. The results of the present study suggest that T. capitatus extracts are a promising alternative to the commercially available anthelmintics like albendazole for the treatment of small ruminants’ gastrointestinal nematodes.

Health management of ewes during pregnancy

The objectives of health management of ewes during pregnancy are as follows: (i) successful completion of pregnancy at term, (ii) birth of healthy and viable lambs, with optimal birth and potential weaning bodyweight, (iii) optimum milk production during the subsequent lactation and (iv) improved management in relation to drug residues in animal products. Knowledge of the physiological background of pregnancy in ewes: changes, mechanisms and interactions, during pregnancy is important for the overall health management of ewes during pregnancy. Health management of pregnant ewes includes diagnosis of pregnancy and evaluation of the number of foetuses borne, which will support strategies for subsequent management of the flock. Nutritional management of ewes depends upon the stage of lactation and specifically aims to (i) prevention of pregnancy toxaemia and other metabolic diseases during the peri-partum period, (ii) formation of colostrum in appropriate quantity and quality, (iii) production of lambs with normal future birth bodyweight and (iv) support of increased milk yield during the subsequent lactation. At the end of lactation, udder management of pregnant ewes includes its clinical examination, culling of ewes considered unsuitable for lactation and, possibly, the intramammary administration of antibiotics; objectives of that procedure are (i) to cure infections which have occurred during the previous lactation and (ii) to prevent development of new mammary infection during the dry period. Management of abortions includes the correct and timely diagnosis of the causative agent of the disorder, as well as the strategic administrations of chemotherapeutic agents, aiming to prevent abortions in flocks with confirmed infection with an abortifacient agent, especially if no appropriate vaccinations had been carried out before the mating season. During the final stage of pregnancy, health management of ewes includes administration of appropriate anthelmintic drugs, aiming to eliminate gastrointestinal helminthes (thus, increasing production output of ewes) and preventing the built-up of parasitic burdens in the environment (thus, reducing infection of lambs during their neonatal period). Vaccinations of pregnant ewes aim to protect these animals, as well as their offspring, especially against diseases which are a frequent cause of neonatal mortality (e.g., clostridial infections). Health management also aims to prevent the main metabolic disorders of pregnant ewes (i.e., pregnancy toxaemia and hypocalcaemia), as well as to monitor flocks for development of these disorders. Health management of pregnant ewes is completed with application of husbandry practices before the start of the lambing season. Finally, in some cases, health management may include induction and synchronisation of lambings, which is a management or therapeutic procedure.

In vitro nematicidal activity of extracts of Canthium mannii (Rubiaceae), on different life-cycle stages of Heligmosomoides polygyrus (Nematoda, Heligmosomatidae)

The increasing prevalence of anthelmintic-resistant strains of helminths, drug residues in animal products and high cost of conventional anthelmintics has created an interest in studying medicinal plants as an alternative source of anthelmintic. The potential nematicidal activities of four extracts from the bark of Canthium mannii (Rubiaceae) stem were investigated in vitro. Extracts were diluted in distilled water (DW) to obtain five different concentrations (1.5, 2.0, 2.5, 3.0 and 3.5 mg/ml) and put in contact with eggs and larvae of Heligmosomoides polygyrus. The different stages of the life cycle were also put in contact with the same concentration of mebendazole (MBZ, positive control). One millilitre of each extract at different concentrations and control were added to 1 ml solution containing 30-40 eggs or 10-15 larvae (L1, L2 and L3) and distributed in different Petri dishes. The eggs and larvae were incubated at 24 degrees C and exposure times were: 48 h for un-embryonated eggs, 6 h for embryonated eggs; 2, 4, 6 and 24 h for L1 and L2 larvae, 24-48 h for infective larvae (L3), and 5 days for the larval development test (from L1 to L3). DW and 1% dimethyl sulphoxide (DMSO) were used as placebo and DMSO control, respectively. Significant effects were obtained with three of the four extracts, and differences were observed depending on the parasite stage. Cold water extract (CWE), hot water extract (HWE) and ethanol extract (ETE) inhibited embryonic development (40, 45 and 10%) and hatching of embryonated eggs (40, 85 and 80%), respectively, at 3.5 mg/ml. Only ETE killed L1 (97.18%) and L2 (92.68%) larvae of H. polygyrus after 24 h at 3.5 mg/ml and drastically reduced the production rate (6% at 3.0 and 3.5 mg/ml) of infective larvae (L3) after 5 days of incubation compared to other extracts (P < 0.05). However, the infective larvae of H. polygyrus were resistant to the effect of each of the tested products (extracts and mebendazole). These in vitro results suggested that extracts of C. mannii, used by traditional healers in Dschang, Western Region of Cameroon (Central Africa) to cure intestinal helminthiasis and abdominal pains of their patients, possess nematicidal properties. The active principles responsible for the activity could be secondary metabolites such as alkaloids and saponins present in the extracts. It is suggested that further experiments incorporating in vivo purification of extracts and toxicological investigations should be carried out.

Anthelmintic activity of extracts of Artemisia absinthium against ovine nematodes

The increasing prevalence of anthelmintic resistant strains of helminths, drug residues in animal products and high cost of conventional anthelmintics has created an interest in studying medicinal plants as an alternative source of anthelmintics. Artemisia absinthium Linn. (Tethwen) is used traditionally by people as a vermifuge in addition to its other livestock uses. The objective of this study was to evaluate the anthelmintic efficacy of crude aqueous extracts (CAE) and crude ethanolic extracts (CEE) of the aerial parts of A. absinthium in comparison to albendazole against the gastrointestinal (GI) nematodes of sheep. To fulfill the objectives, the worm motility inhibition assay was utilized in order to investigate the direct effects of plant extracts on the survival of the adult nematodes under in vitro conditions and faecal egg count reduction assay to investigate the effects on faecal egg output of GI nematodes under in vivo conditions. Significant anthelmintic effects of CAE and CEE on live adult Haemonchus contortus worms ( P < 0.005) were observed in terms of the paralysis and/or death of the worms at different hours post-treatment (PT), however, CEE were more efficacious than CAE. The oral administration of the extracts in sheep was associated with significant reduction in faecal egg output by the GI nematodes. The CEE was as effective as the reference drug-albendazole and demonstrated faecal egg count reduction (FECR) of 90.46% in sheep at 2.0 g kg −1 body weight on day 15 PT followed by 82.85% FECR at 1.0 g kg −1 bw on day 15 PT. The CAE showed less activity and resulted in maximum of 80.49% FECR at 2.0 g kg −1 bw. Dosage had a significant ( P < 0.05) influence on the anthelmintic efficacy of A. absinthium. The better activity of CEE can be attributed to the greater concentration of alcohol soluble active anthelmintic principle/s and a more rapid transcuticular absorption of the CEE into the body of the worms when compared with the CAE. The results of the present study suggest that A. absinthium extracts are a promising alternative to the commercially available anthelmintics for the treatment of GI nematodes of sheep.

Drug Residue Avoidance Practices in Dairy Cattle

Veterinary drugs are routinely used in the dairy industry. The Federal Food, Drug, and Cosmetic Act specifically mentions veterinarians as individuals who could be responsible for illegal drug residues in edible animal products. Despite the laws and inspection activities by federal agencies, drug residues in animal products continue to cause public health concern. Of particular concern are culled dairy cows that are eventually sold for beef. Previous research has found the greatest level of drug residue violations in beef from cull dairy cows and bob veal in the United States. As part of the development of an overall educational program for dairy beef quality assurance, an industry-wide group wanted to assess the knowledge, practices and attitudes of bovine veterinarians and dairy producers concerning beef quality assurance, with particular emphasis on drug residue avoidance. Two survey instruments were developed for dairy producers and for veterinarians in order to identify effective methods for educational outreach