Continuous exposure to an aversive mixture as a means of maintaining aversion to vermeerbos (Geigeria ornativa O. Hoffm.) in the presence of non-averted sheep

Continuous exposure to an aversive mixture was investigated as a means of maintaining aversion to vermeerbos in sheep subjected to the social influence of non-averted sheep. The use of an aversive mixture was based on a hypothesis that continuous exposure to an acceptable aversive mixture (containing both the aversive substance and the identification factors of vermeerbos mixed with maize meal) would tempt sheep to consume small quantities of the aversive mixture each day and that this would keep them averted to vermeerbos, despite the social influence of non-averted sheep. Persistent aversion to a vermeerbos-maize meal mixture (1:99 by mass) by sheep continuously exposed to such an aversive mixture, after an initial aversion conditioning with lithium chloride (LiCl, 160 mg/kg BM), was demonstrated. Aversion in adjacent controls not exposed to the aversive mixture only lasted for some time. A similar result was obtained when sheep were challenged for intake of a pure stand of established vermeerbos. Three sheep continuously exposed to an aversive mixture after an initial aversion conditioning totally refused grazing the vermeerbos during a 42-day trial, despite the social influence of three non-averted control sheep grazing vermeerbos on an adjacent site. These results were confirmed by a second replication the following year. Joint grazing for an hour a day by averted and non-averted sheep during the last seven days of this replication also resulted in total avoidance of vermeerbos by the averted animals, despite continued intake of vermeerbos by the control sheep     

Adverse influence of social facilitation and learning context in training cattle to avoid eating larkspur

Through conditioned food aversion learning, livestock can be trained to avoid eating harmful plants. The objectives of this study were to determine whether social facilitation will extinguish an aversion to larkspur (a poisonous plant on mountain rangelands) and to determine whether the aversion can be reinforced to withstand social facilitation in a group-feeding and field-grazing situation. Two groups of heifers offered fresh larkspur were simultaneously infused intraruminally with lithium chloride (LiCl) to create an association between the taste of larkspur and LiCl-induced gastrointestinal distress. A third control group was infused with water. Heifers from one averted group (extinction) were paired with nonaverted controls and offered larkspur. When the extinction group sampled larkspur, and LiCl was not infused, the aversion was extinguished rapidly. Heifers in the other averted group (reinforcement), being infused with LiCl whenever they sampled larkspur, abstained from eating larkspur in the group-feeding situation. Heifers were then taken to larkspur-infested rangeland. After the control heifers began eating larkspur, the averted heifers started to sample it and the aversion was extinguished in three of four heifers. However, the aversion was renewed when the heifers were returned to the pen- and group-feeding situation where the aversion was created. Reinforced aversion was overcome by social facilitation in an unfamiliar field-grazing environment.     

Effect of heat killed Mycobacterium phlei on body weight gain and management of caecal coccidiosis in broiler chickens

The objective of this study was to evaluate the immunotherapeutic potential of heat killed Mycobacterium phlei in broiler chicken against experimentally produced Eimeria tenella infection. The selected dose of E. tenella oocyst (5 × 10³ sporulated oocysts per bird) was capable of producing a mild form of caecal coccidiosis as observed by significant difference in body weight gain, clinical findings and caecal lesion score. Heat killed M. phlei was fed orally at 10 mg per bird with sterile PBS vehicle at alternate day for four doses. Our study reveals that per day body weight gain was significantly (p < 0.01) higher for healthy control compared to coccidia infected group. The group fed M. phlei along with coccidial challenge showed significantly (p < 0.05) higher body weight gain than infected control group. Heat killed M. phlei feeding also found effective to reduce the caecal lesion score significantly (p < 0.05) in comparison to E. tenella infected untreated group. IgA concentrations in serum and bile at 7-day post challenge of coccidial oocyst was also significantly (p < 0.01) higher in M. phlei fed group when compared to coccidia infected and healthy control group. We concluded that use of heat killed M. phlei has a beneficial role as an immunostimulant against caecal coccidiosis in broiler chicken.     

Effect of previous locoweed (Astragalus and Oxytropis species) intoxication on conditioned taste aversions in horses and sheep

Locoweed species (Astragalus and Oxytropis spp.) are a serious toxic plant problem for grazing livestock. Horses and sheep have been conditioned to avoid eating locoweed using the aversive agent LiCl. The objective of this study was to determine if previous locoweed intoxication affects food aversion learning in horses and sheep. Horses and sheep were divided into 3 treatment groups: control (not fed locoweed and not averted to a novel feed); locoweed-novel feed averted (fed locoweed and averted to a novel feed); and averted (not fed locoweed and averted to a novel feed). Animals in the locoweed-novel feed averted groups were fed locoweed during 2 periods of 21 and 14 d, respectively, with each feeding period followed by a 14-d recovery period. Animals were averted to a novel test feed at the end of the first locoweed-feeding period, and periodically evaluated for the strength and persistence of the aversion. During the first recovery period, locoweed-novel feed averted horses ate less (9.5% of amount offered) of the test feed than did control horses (99.8%) and did not generally differ from averted horses (0%). During recovery period 2, locoweed-novel feed averted horses (4.3%) differed (P = 0.001) in consumption (% of offered) of the test feed from controls (100%) and the averted group (0%). Locoweed-novel feed averted sheep differed (P = 0.001) from controls (14.4 vs. 99.5%, respectively, during recovery period 1), whereas locoweed-novel feed averted sheep did not differ (P > 0.50) from averted sheep (0.6%). During the second recovery period, control sheep (100%) differed (P < 0.05) from averted (0%) and locoweed-novel feed averted (12.2%) groups. Two intoxicated sheep (locoweed-novel feed averted) partially extinguished the aversion during the first recovery period, but an additional dose of LiCl restored the aversion. Two of 3 intoxicated horses had strong aversions that persisted without extinction; 1 horse in the locoweed-novel feed averted group had a weaker aversion. These findings suggest that horses and sheep previously intoxicated by locoweeds can form strong and persistent aversions to a novel feed, but in some animals, those aversions may not be as strong as in animals that were never intoxicated.     

Comparison of larkspur alkaloid extract and lithium chloride in maintaining cattle aversion to larkspur in the field.

Lithium chloride (LiCl) and larkspur (Delphinium barbeyi) alkaloid extract were compared in their effect as an emetic to create taste aversions to fresh larkspur. They were further compared in the field to determine whether the indigenous larkspur alkaloids were more effective in maintaining the aversion when conditioned cattle were subjected to the social pressure (social facilitation) of control cattle eating larkspur. Taste aversions were produced in two groups of 1-yr-old cattle by offering fresh larkspur and then gavaging with either LiCl at 200 mg/kg of BW or larkspur alkaloid extract at 1.1 to 1.6 mL/kg of BW. The third group (control) was gavaged with water. The alkaloid group was slower to form an aversion than the lithium group, requiring four doses compared with two doses. All groups were then taken to larkspur-infested rangeland to test the aversion in the field. In the first field trial in which groups grazed separately, both aversion-induced groups generally abstained from eating larkspur. In the second trial in which all groups grazed together, both aversion-induced groups consumed less than half as much larkspur as the controls, but neither group abstained completely. Larkspur alkaloids did not maintain the aversion to larkspur to a greater degree than did LiCl when aversion-induced cattle were subjected to social facilitation.     

Eliciting conditioned taste aversion in lizards: Live toxic prey are more effective than scent and taste cues alone

Conditioned taste aversion (CTA) is an adaptive learning mechanism whereby a consumer associates the taste of a certain food with symptoms caused by a toxic substance, and thereafter avoids eating that type of food. Recently, wildlife researchers have employed CTA to discourage native fauna from ingesting toxic cane toads (Rhinella marina), a species that is invading tropical Australia. In this paper, we compare the results of 2 sets of CTA trials on large varanid lizards (“goannas,” Varanus panoptes). One set of trials (described in this paper) exposed recently‐captured lizards to sausages made from cane toad flesh, laced with a nausea‐inducing chemical (lithium chloride) to reinforce the aversion response. The other trials (in a recently‐published paper, reviewed herein) exposed free‐ranging lizards to live juvenile cane toads. The effectiveness of the training was judged by how long a lizard survived in the wild before it was killed (fatally poisoned) by a cane toad. Both stimuli elicited rapid aversion to live toads, but the CTA response did not enhance survival rates of the sausage‐trained goannas after they were released into the wild. In contrast, the goannas exposed to live juvenile toads exhibited higher long‐term survival rates than did untrained conspecifics. Our results suggest that although it is relatively easy to elicit short‐term aversion to toad cues in goannas, a biologically realistic stimulus (live toads, encountered by free‐ranging predators) is most effective at buffering these reptiles from the impact of invasive toxic prey.     

Long-term immunogenicity and protection against Mycoplasma agalactiae induced by an oil adjuvant vaccine in sheep

The long-term protective immunity of an inactivated mineral-oil adjuvanted Mycoplasma agalactiae vaccine was evaluated in sheep. The antigen suspension was emulsified with a mixture of three mineral oils (Montanide ISA-563, Marcol-52, Montane-80 at the ratio of 30%, 63%, and 7%, respectively). Twenty-two animals were divided in 2 groups (A and B) and immunised with two doses of the vaccine (group A, n = 14) or used as unvaccinated control (group B, n = 8). Five months after the second vaccination, seven animals of group A and four animals of group B were challenged by nasal route with M. agalactiae. The remaining seven vaccinated and four control animals were challenged intranasally eight months after vaccination. The vaccine was able to induce a full-protective immunity preventing the clinical signs of contagious agalactia and the infection by M. agalactiae in all groups of animals irrespective of the time of challenge after booster administration.     

Combined subcutaneous administration of ivermectin and nitroxynil in sheep: Age/body weight related changes to the kinetic disposition of both compounds

The effect of age/body weight in the plasma disposition kinetics of ivermectin (IVM) and nitroxynil (NTX) after their co-administration as a combined formulation to sheep was studied. Sixteen (16) male sheep were allocated into two experimental groups (n = 8 each): (a) high body weight (high bw) (18-20 months old), and (b) low body weight (low bw) (6-8 months old). Animals in both groups were subcutaneously (sc) treated with IVM (200 μg/kg) and NTX (10 mg/kg) using a commercially available combined formulation (Nitromectin^®, Lab. Ovejero, Spain). Blood samples were taken by jugular venopuncture before (time 0), at 2, 4, 8, 12 h and at 1, 2, 3, 5, 7, 10, 15, 20, 25, 35, 40, 50 and 60 days after administration. Recovered plasma was analysed to quantify IVM and NTX by HPLC. Higher IVM plasma concentrations were measured until 20 days post-administration in “low bw” compared to “high bw” animals, where IVM was recovered up to 35 days post-treatment. The IVM absorption process greatly differed between experimental groups. A significantly higher (p < 0.01) C_max (36.7 ± 7.52 ng/ml) value was obtained at a delayed (p < 0.05) T_max (48.0 ± 0.0 h) in light compared to heavy (C_max: 8.0 ± 0.80 ng/ml; at 34.0 h) body weight sheep. IVM elimination half-life and mean residence time were significantly shorter in light compared to heavy (older) sheep. NTX mean plasma concentrations were lower in “low bw” compared to those measured in “high bw” sheep, with elimination phases declining up to 60 d post-administration in both experimental groups. The NTX AUC value in “low bw” (1188.5 ± 122.6 μg day/ml) was significantly lower (p < 0.05) than that obtained in the “high bw” (oldest) animals (1735.0 ± 155.8 μg day/ml). Shorter NTX elimination half-life and mean residence time (p < 0.01) were obtained in the youngest (“low bw”) compared to the oldest (high bw) sheep. The work reported here assessed for the first time the disposition of IVM and NTX after their combinated injection to sheep, demonstrating that animal body weight/development greatly affects the kinetic behaviour of both anthelmintic drugs.     

Assessing the efficacy of Duddingtonia flagrans chlamydospores per gram of faeces to control Haemonchus contortus larvae

The aims were (a) to quantify the number of Duddingtonia flagrans chlamydospores per gram of faeces (CPG) recovered from sheep administered with different oral doses and, (b) to describe the relationship between CPG and eggs per gram of faeces (EPG) on the efficacy to reduce Haemonchus contortus infective larvae. Three doses of chlamydospores per kg BW were orally administered during seven days: (T1) non treated control group, (T2) 1 × 10⁶, (T3) 2.5 × 10⁶ and (T4) 5 × 10⁶. Three lambs, infected with H. contortus, were used per group. Faeces were obtained from the rectum of each lamb during the fungal administration period (days 0–6) and for six days after that period. Four coproculture replicates were made from each animal in days 2, 4, 6, 8 and 10. A higher chlamydospore dose produced higher CPG in faeces (p < 0.05), but a clear dose dependent effect was not found either in the larvae reduction or in the CPG:EPG ratio. When ratios were re-analyzed, independently of the treatment groups of origin, a better efficacy was obtained with a ratio from 5 to 10 CPG:EPG and a higher ratio (>10 per egg) showed a lower reduction efficacy (p < 0.05). The binomial analysis showed that for each unit of increment in CPG:EPG ratio there was a reduction of larvae number until a point (between 5 and 10 CPG:EPG) where no further reduction was detected. The surface response test indicated that the number of larvae was reduced by CPG until possible saturation. The highest CPG:EPG ratios did not necessarily improve efficacy of D. flagrans.     

Prevalence of gastrointestinal helminths,lungworms and liver fluke in sheep and goats in Norway

The present study describes the occurrence of various gastrointestinal helminths, lungworms and liver flukes in Norwegian sheep and goats as assessed from faecal samples and post mortem examinations performed between 2007 and 2010. Faecal samples for gastrointestinal nematode egg counts were collected from 77 sheep flocks and 30 dairy goat flocks from three geographical regions in Norway. Additionally, thirty-two lambs and 16 adult goats were euthanized for necropsy examination and for identification of adult gastrointestinal nematodes and tapeworms, lungworms and liver flukes. The survey showed that there was a higher mean excretion of trichostrongyle eggs in sheep than in goats at the individual level (392 EPG vs. 154 EPG, p < 0.001). For both host species, the mean prevalence and intensity of excreted trichostrongyle eggs were significantly higher in the southern coastal region compared with the inland and northern regions (p < 0.001). Third stage larvae of Trichostrongylus/Teladorsagia, Haemonchus and Nematodirus type were the most prevalent ones in the coprocultures from sheep, whereas larvae of Trichostrongylus/Teladorsagia and Nematodirus type dominated in goats. The most prevalent gastrointestinal nematode species found at necropsy was Teladorsagia circumcincta (75.0 and 81.2% respectively in sheep and goats), while the largest mean worm burdens were recorded for Haemonchus contortus in sheep (724 ± 623) and T. circumcincta in goats (377 ± 529). Other gastrointestinal nematode species were present at low prevalence or in low numbers.     

Learning Through Foraging Consequences: A Mechanism of Feeding Niche Separation in Sympatric Ruminants

Explanations for why sympatric ruminant species select diets composed of different plant species or plant parts have been controversial. Our explanation is based on learning from foraging consequences, which includes the influences that morphology, physiology, and experience have on diet selection. We conducted a trial with cattle (Bos taurus), sheep (Ovis aries), and goats (Capra hircus) and leafy spurge (LS; Euphorbia esula L.) to explore the interface between the learning and morphophysiological foraging models with these sympatric ruminants. After a pretrial adjustment period, the control group for each species received, via stomach tube on days 1 and 2, ground grass after eating a novel food (NF; rolled corn), and the treatment group for each species received ground air-dried LS after eating the NF. NF intake on days 2 and 3 was expressed as a percent of NF intake on day 1, and it declined considerably for cattle and sheep dosed with LS but did not decline for goats receiving it (P = 0.001). LS elicited learned aversive feeding responses from cattle and sheep but not from goats. The results are consistent with field observations that goats graze LS more readily than sheep or cattle do. Learning from foraging consequences offers an explanation for the unique diets of sympatric ruminant species.     

Alfalfa polysaccharides improve the growth performance and antioxidant status of heat-stressed rabbits

The study was conducted to evaluate the antioxidant properties of alfalfa polysaccharides (APS) extracted from alfalfa (Medicago sativa L.) through 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) radical-scavenging assay and the effects of the inclusion (0%, 0.1%, and 0.5%) of APS in the diet on the growth performance and antioxidant status in heat-stressed rabbits. 120 New Zealand male rabbits (average body weight 1123 g, 40 d old) were divided into three groups (40 rabbits per group) and were fed with a basal diet or the basal diet with 1 g or 5 g of APS/kg of diet. Rabbits had free access to diets and water in an environmentally controlled room at 30 ± 1 °C and 55% relative humidity during the entire period (21 d). On days 7, 14 and 21 of the trial, body weight and feed intake were measured and blood samples were collected for assay of antioxidant induces. Liver tissue samples were collected on day 21 for assay of antioxidant induces. Results in vitro showed the scavenging effect of APS on DPPH radicals increased (P < 0.05) in a dose-dependent manner. The APS exerted an inhibitory effect on DPPH radical generation, with 66.3% inhibition at 100 µg/mL and 74.5% inhibition at 250 µg/mL. Results in vivo showed that APS 0.1% supplementation increased (P < 0.05) average daily gain (ADG) and reduced (P < 0.05) feed conversion rate (FCR) in the first week of trial. Compared with the control group, average daily feed intake (ADFI) was significantly (P < 0.01) reduced by APS treatment. From days 8 to 14 of the trial, ADG of the APS 0.5% group was greater (P < 0.05) than that of the control group. Compared with the control group, FCR was significantly (P < 0.05) reduced by APS treatment. From days 15 to 21 of the trial, ADFI of the APS 0.1% group was greater (P < 0.05) than that of the control group. For the overall period, APS 0.5% supplementation had a significantly (P < 0.05) positive effect on ADG. ADFI and FCR were lower (P < 0.05) with APS than without APS. Furthermore, on day 7, the inclusion of APS reduced significantly MDA (P < 0.01). The rabbits fed with APS 0.1% had significantly (P < 0.01) lower cortisol and greater (P < 0.05) T-AOC, SOD, and GSH-Px than the control group. On day 14, addition of APS increased T-AOC (P < 0.01) and reduced MDA (P < 0.05). The APS 0.5% group showed lower (P < 0.05) cortisol and greater (P < 0.05) GSH-Px than the control group. On day 21, the rabbits fed with the APS 0.5% diet had greater (P < 0.05) GSH-Px and T-AOC compared with the control rabbits. In contrast, the opposite was true for cortisol (P < 0.05) and MDA (P < 0.05). On day 21, MDA was lower (P < 0.01) with APS than without APS in the liver tissue. Hepatic GSH-Px activity of rabbits fed with the APS 0.5% diet was greater (P < 0.05) than those of other groups. APS supplementation seemed to have a positive influence on the growth performance and antioxidant status of heat-stressed rabbits.     

Performance and ruminal protozoa in lambs with chromium supplementation

The effects of chromium picolinate (CrPic) oral supplementation on the performance and ruminal protozoa population in sheep was investigated. Twenty-four male lambs were treated with four different levels of CrPic: placebo, 0.250, 0.375 and 0.500 mg of chromium/animal/day during 84 days. The base ration was Panicum maximum cv Massai hay and concentrate. Feed intake was measured three times a week. Lambs were weighed every 2 weeks. Ruminal content was sampled five times during the trial to quantify ruminal protozoa. No difference (p > 0.05) between treatments was recorded for any parameter measured: initial and final mean body weight, dry matter intake, daily gain and total body weight gain. There was a negative linear relationship between Cr supplementation and protozoa count (p = 0.0013) with no additional decrease when CrPic supplemental levels were higher than 0.375 mg/day. Therefore, Cr supplementation must be carried out carefully and more studies need to address stressed animals or possible toxic effects of Cr in the animal itself or to the ruminal protozoa population.     

Determination of oral tramadol pharmacokinetics in horses

The determination of the pharmacokinetic parameters of tramadol in plasma and a better characterization of its metabolites after oral administration to horses is necessary to design dosage regimens to achieve target plasma concentrations that are associated with analgesia. The purpose of this study was to determine the pharmacokinetics and elimination pattern in urine of tramadol and its metabolites after oral administration to horses. Tramadol was administered orally to six horses and its half-life, T_max and C_max in plasma were 10.1, 0.59 h, and 132.7 ng/mL, respectively. The half-life, T_max and C_max for M1 in plasma were 4.0, 0.59 h, and 28.0 ng/mL, respectively. Tramadol and its metabolites were detectable in urine between 1 and 24 h after the administration. In conclusion, the PK data reported in this study provides information for the design of future studies of tramadol in horses.     

Bovine respiratory disease: efficacy of different prophylactic treatments in veal calves and antimicrobial resistance of isolated Pasteurellaceae

The present study was conducted to evaluate the efficacy of two prophylactic antibiotic treatments against bovine respiratory disease (BRD) in veal calves. In addition, the antibiotic susceptibilities of isolated Pasteurellaceae were tested. The calves were treated either on the day of arrival by a single administration of tulathromycin (group A, n = 20), by a peroral administration of chlortetracycline, sulphadimidine, and tylosin (group B, n = 20) for seven consecutive days, or were not prophylactically treated (group C, n = 19). On the first day of clinically diagnosed BRD, transtracheal lavage samples were obtained prior to therapeutic treatment and were subsequently cultured. Pasteurellaceae isolates were tested for their susceptibility to 12 antimicrobial agents by the determination of the minimal inhibitory concentrations. During the first 56 d after arrival, different calves in group A and B suffered from one episode of clinically diagnosed BRD while calves of group C experienced two episodes. The average daily weight gain during the same period was significantly lower in group C (0.89 ± 0.04 kg/d) than in the two prophylactically treated groups (1.14 ± 0.05 and 1.15 ± 0.04 kg/d for group A and B, respectively). The improved performance of groups A and B in comparison to group C could be related to a lower incidence of respiratory disorders during the first days after arrival in the prophylactically treated animals. No differences in the clinical efficacy were seen between the two tested prophylactic treatments. The most prevalent bacterial pathogens isolated (n = 79) were Pasteurella multocida (23% of isolated pathogens), Mycoplasma bovis (18%), and Mannheimia varigena (16%). For the isolated Pasteurellaceae, a high resistance pattern was observed to tylosin (83% of the tested P. multocida and 88% of the Mannheimia spp. isolates resistant) and tilmicosin (56% of the tested P. multocida isolates non-sensitive).     

Seroprevalence of and risk factors for Toxoplasma gondii in sheep raised in the Jaboticabal microregion, São Paulo State, Brazil

Seroprevalence of and risk factors for toxoplasmosis in sheep from different properties in the Jaboticabal microregion, São Paulo State, Brazil were determined. Antibodies to Toxoplasma gondii were found in sera of 52.0% of 488 sheep tested by indirect fluorescent antibody test (IFAT ? 64). T. gondii seropositivity in sheep was significantly associated with gender of the sheep, pasturing system, contact with cats, and the use of mineral supplements and the type of feed.     

Effects of 1,25-dihydroxyvitamin D3 on calcium and phosphorus homeostasis in sheep fed diets either adequate or restricted in calcium content

It was the aim of the present study to collect basic data on calcium (Ca) and phosphorus (P) homoeostasis in sheep. Two series of experiments were carried out to investigate the effects of 1,25-dihydroxyvitammin D₃ (calcitriol) in supraphysiological dosage in combination with varying alimentary Ca supply. In the first series, blood samples were collected over 72 h to determine the concentrations of total Ca (Ca), ionized Ca (Ca²⁺), inorganic phosphate (P_i), and the bone resorption marker CrossLaps (CL). In the second series, measurements were carried out over 12 h. In addition, urine samples were collected to calculate the fractional excretions (FE) of Ca and P_i. Changes in plasma macromineral concentrations (P < 0.01) as well as in CL (P < 0.001) and endogenous calcitriol (P < 0.05) were observed in the alimentary Ca-restricted animals, indicating that the reduction of daily Ca intake challenged the animals’ macromineral homeostatic mechanisms. However, the Ca-restricted diet had an effect on neither FE of Ca nor on FE of P_i. The treatment resulted in peak serum calcitriol concentrations between 1,900 and 2,500 pg/mL, and supraphysiological concentrations were maintained for the next 48 h. Irrespective of dietary Ca, calcitriol had hypercalcemic and hyperphosphatemic effects. An increase in CL was revealed only in the Ca-restricted, calcitriol-treated sheep (P < 0.01), reflecting a remarkable enhancement of Ca mobilization from the bone by calcitriol exclusively in this group. From these data, it can be concluded that the sheep can be a suitable animal model for studying catabolic effects of Ca deficiency and calcitriol on bone metabolism.     

Efficacy of a single high oxfendazole dose against gastrointestinal nematodes in naturally infected pigs

The goal of the current experiment was to assess the clinical efficacy of oxfendazole (OFZ) administered as a single oral dose (30 mg/kg) to pigs naturally parasitized with Ascaris suum, Oesophagostomum spp., Metastrongylus spp. and Trichuris suis. Thirty-six local ecotype piglets were divided into three independent experiments, named I, II and III (n = 12 each), respectively. Each experiment involved two different groups (n = 6): Untreated Control and OFZ treated. Animals were naturally parasitized with A. suum (Experiments I, II and III), Oesophagostomum spp. (Experiments I and II), T. suis (Experiments II and III) and Metastrongylus spp. (Experiment I). Pigs in the treated group received OFZ (Synanthic^®, Merial Ltd., 9.06% suspension) orally at 30 mg/kg dose. At five (5) days post-treatment, animals were sacrificed and the clinical efficacy of the OFZ treatment was established following the currently available WAAVP guidelines for a controlled efficacy test. None of the animals involved in this experiment showed any adverse events during the study. OFZ treatment given as a single 30 mg/kg oral dose showed a 100% efficacy against all the nematode parasites present in the three experiments. In conclusion, under the current experimental conditions, OFZ orally administered to naturally parasitized piglets at a single dose of 30 mg/kg was safe and highly efficacious (100%) against adult stages of A. suum, Oesophagostomum spp., T. suis and Metastrongylus spp.     

Prevalence and risk factors for Coxiella burnetii (Q fever) in Dutch dairy cattle herds based on bulk tank milk testing

Despite cattle herds can harbor Coxiella burnetii, risk factors for C. burnetii presence in dairy cattle herds are largely unknown. Therefore, C. burnetii herd prevalence and risk factors for bulk tank milk (BTM) positivity were investigated. In this cross-sectional study, a questionnaire was filled out by the farmer and BTM from 301 farms was tested by ELISA for presence of C. burnetii antibodies and PCR for presence of C. burnetii DNA. Risk factors were identified by univariable and multivariable logistic regression analyses. Antibodies to C. burnetii were detected in 81.6% (CI: 77.2–85.9) and C. burnetii DNA in 18.8% (CI: 14.4–23.1) of the BTM samples. Herd size (OR = 1.1 per 10 cows), cleaning the bedding of the cubicles at most every other day (OR = 2.8) and purchase of cattle from at least two addresses (OR = 3.1) showed a significant and positive association with ELISA positivity and use of an automatic milking system a negative association (OR = 0.3). Risk factors for PCR positivity were purchase of cattle from at least two delivery addresses (OR = 3.2), presence of cows with ticks (OR = 2.0), use of an automatic milking system (OR = 0.2) and presence of goats or sheep on the farm (OR = 0.4). Biosecurity and general hygiene seem associated with introduction and spread of C. burnetii in dairy herds.