Worm control practice against gastro-intestinal parasites in Norwegian sheep and goat flocks

Background

Anthelmintic treatment is the most common way of controlling nematode infections in ruminants. However, several countries have reported anthelmintic resistance (AR), representing a limitation for sustainable small ruminant production. The knowledge regarding worm control management represents a baseline to develop a guideline for preventing AR. The aim of the present study was therefore to improve our knowledge about the worm control practices in small ruminant flocks in Norway.

Methods

A questionnaire survey regarding worm control practices was performed in small ruminant flocks in Norway. Flocks were selected from the three main areas of small ruminant farming, i.e. the coastal, inland and northern areas. A total of 825 questionnaires, comprising 587 sheep flocks (return rate of 51.3%) and 238 goat flocks (52.6%) were included.

Results

The results indicated that visual appraisal of individual weight was the most common means of estimating the anthelmintic dose used in sheep (78.6%) and goat (85.1%) flocks. The mean yearly drenching rate in lambs and ewes were 2.5 ± 1.7 and 1.9 ± 1.1, respectively, whereas it was 1.0 (once a year) in goats. However, these figures were higher in sheep in the coastal area with a rate of 3.4 and 2.2 in lambs and ewes, respectively. Benzimidazoles were the predominant anthelmintic class used in sheep flocks (64.9% in 2007), whereas benzimidazoles and macrocyclic lactones were both equally used in dairy goat flocks. In the period of 2005-2007, 46.3% of the sheep flocks never changed the anthelmintic class. The dose and move strategy was practiced in 33.2% of the sheep flocks.

Conclusions

The present study showed that inaccurate weight calculation gives a risk of under-dosing in over 90% of the sheep and goat flocks in Norway. Taken together with a high treatment frequency in lambs, a lack of anthelmintic class rotation and the common use of a dose-and-move strategy, a real danger for development of anthelmintic resistance (AR) seems to exist in Norwegian sheep and goat flocks. This risk seems particularly high in coastal areas where high treatment frequencies in lambs were recorded.     

Risk factors for porcine reproductive and respiratory syndrome outbreaks in Vietnamese small stock farms

AIM: To examine risk factors that could have played a role in the 2010 porcine reproductive and respiratory syndrome (PRRS) outbreak in Yenhung district, Quangninh province, North-Vietnam, with the purpose of establishing why existing control measures implemented after previous outbreaks had failed to prevent further outbreaks.

METHODS: A case-control study was carried out in Yenhung district. Data were obtained by an interview-based questionnaire survey. The sampling unit was households, which equated to small-scale pig farms. A total of 150 case and 150 control households were selected at communes affected by the 2010 PRRS epidemic during April to June. Risk factors were analysed using binary logistic regression and unconditional multiple logistic regression.

RESULTS: Households infected with PRRS were significantly associated with multiple variables belonging to three main groups: (1) location of the farms: i.e. farms positioned <1,000?m from a pig abattoir or within 500?m of local markets or 100?m of main roads; (2) farm management: i.e. where there was non-application of weekly farm disinfection, feeding uncooked swill, new introduction of purchased pigs without isolation, or usage of water from irrigation systems for raising pigs; (3) people and animal contact: i.e. where households kept animals with either no confinement or partial confinement, had visits by family members to other affected farms or had frequent visits by neighbours. The use of water from irrigation systems was found to be the risk factor most strongly associated with infected households in the 2010 outbreak (OR=22; 95% CI=12–42).

CONCLUSIONS: The results show that the epidemiology of PRRS in Quangninh province was linked to sociological and cultural practices, and that effective PRRS control needs an integrated approach coupled with behavioural changes in the pig raising practices of the general public. Failure to recognise this could explain why further outbreaks have occurred.     

Evaluation of the isoflurane‐sparing effects of fentanyl,lidocaine, ketamine,dexmedetomidine, or the combination lidocaine‐ketamine‐dexmedetomidine during ovariohysterectomy in dogs

ObjectiveTo evaluate the isoflurane‐sparing effects of an intravenous (IV) constant rate infusion (CRI) of fentanyl, lidocaine, ketamine, dexmedetomidine, or lidocaine‐ketamine‐dexmedetomidine (LKD) in dogs undergoing ovariohysterectomy.Study designRandomized, prospective, blinded, clinical study.AnimalsFifty four dogs.MethodsAnesthesia was induced with propofol and maintained with isoflurane with one of the following IV treatments: butorphanol/saline (butorphanol 0.4 mg kg^?1, saline 0.9% CRI, CONTROL/BUT); fentanyl (5 μg kg^?1, 10 μg kg^?1 hour^?1, FENT); ketamine (1 mg kg^?1, 40 μg kg^?1 minute^?1, KET), lidocaine (2 mg kg^?1, 100 μg kg^?1 minute^?1, LIDO); dexmedetomidine (1 μg kg^?1, 3 μg kg^?1 hour^?1, DEX); or a LKD combination. Positive pressure ventilation maintained eucapnia. An anesthetist unaware of treatment and end‐tidal isoflurane concentration (Fe′Iso) adjusted vaporizer settings to maintain surgical anesthetic depth. Cardiopulmonary variables and Fe′Iso concentrations were monitored. Data were analyzed using anova (p < 0.05).ResultsAt most time points, heart rate (HR) was lower in FENT than in other groups, except for DEX and LKD. Mean arterial blood pressure (MAP) was lower in FENT and CONTROL/BUT than in DEX. Overall mean ± SD Fe′Iso and % reduced isoflurane requirements were 1.01 ± 0.31/41.6% (range, 0.75 ± 0.31/56.6% to 1.12 ± 0.80/35.3%, FENT), 1.37 ± 0.19/20.8% (1.23 ± 0.14/28.9% to 1.51 ± 0.22/12.7%, KET), 1.34 ± 0.19/22.5% (1.24 ± 0.19/28.3% to 1.44 ± 0.21/16.8%, LIDO), 1.30 ± 0.28/24.8% (1.16 ± 0.18/32.9% to 1.43 ± 0.32/17.3%, DEX), 0.95 ± 0.19/54.9% (0.7 ± 0.16/59.5% to 1.12 ± 0.16/35.3%, LKD) and 1.73 ± 0.18/0.0% (1.64 ± 0.21 to 1.82 ± 0.14, CONTROL/BUT) during surgery. FENT and LKD significantly reduced Fe′Iso.Conclusions and clinical relevanceAt the doses administered, FENT and LKD had greater isoflurane‐sparing effect than LIDO, KET or CONTROL/BUT, but not at all times. Low HR during FENT may limit improvement in MAP expected with reduced Fe′Iso.     

Clinical evaluation of ketamine and lidocaine intravenous infusions to reduce isoflurane requirements in horses under general anaesthesia

ObjectiveTo compare isoflurane alone or in combination with systemic ketamine and lidocaine for general anaesthesia in horses.Study designProspective, randomized, blinded clinical trial.AnimalsForty horses (ASA I-III) undergoing elective surgery.MethodsHorses were assigned to receive isoflurane anaesthesia alone (ISO) or with ketamine and lidocaine (LKI). After receiving romifidine, diazepam, and ketamine, the isoflurane end-tidal concentration was set at 1.3% and subsequently adjusted by the anaesthetist (unaware of treatments) to maintain a light plane of surgical anaesthesia. Animals in the LKI group received lidocaine (1.5 mg kg⁻¹ over 10 minutes, followed by 40 μg kg⁻¹ minute⁻¹) and ketamine (60 μg kg⁻¹ minute⁻¹), both reduced to 65% of the initial dose after 50 minutes, and stopped 15 minutes before the end of anaesthesia. Standard clinical cardiovascular and respiratory parameters were monitored. Recovery quality was scored from one (very good) to five (very poor). Differences between ISO and LKI groups were analysed with a two-sample t-test for parametric data or a Fischer's exact test for proportions (p < 0.05 for significance). Results are mean ± SD.ResultsHeart rate was lower (p = 0.001) for LKI (29 ± 4) than for ISO (34 ± 6). End-tidal concentrations of isoflurane (ISO: 1.57% ± 0.22; LKI: 0.97% ± 0.33), the number of horses requiring thiopental (ISO: 10; LKI: 2) or dobutamine (ISO:8; LKI:3), and dobutamine infusion rates (ISO:0.26 ± 0.09; LKI:0.18 ± 0.06 μg kg⁻¹ minute⁻¹) were significantly lower in LKI compared to the ISO group (p < 0.001). No other significant differences were found, including recovery scores.Conclusions and clinical relevanceThese results support the use of lidocaine and ketamine to improve anaesthetic and cardiovascular stability during isoflurane anaesthesia lasting up to 2 hours in mechanically ventilated horses, with comparable quality of recovery.     

Current attitudes to,and use of,peri-operative analgesia in dogs and cats by veterinarians in New Zealand

AIM: To investigate the attitudes of veterinary practitioners in New Zealand to pain and analgesia, and their use of analgesic drugs, in dogs and cats.

METHODS: A questionnaire posted to 1,200 practising veterinarians was used to gather information about the use of analgesia in dogs and cats, assessment of pain, attitudes to pain relief, analgesic drugs and procedures used, factors affecting choice of analgesic agent, and veterinary demographics, continuing education and staffing.

RESULTS: Three hundred and twenty questionnaires with useable data were returned, a response rate of 28%. Male and female veterinarians were evenly represented. The analgesic agents most commonly used were morphine (opioids) and carprofen (a non-steroidal anti-inflammatory drug; NSAID). Use of peri-operative pain relief ranged from 50% for castration of cats to 91% for fracture repair in dogs. For most procedures, female veterinarians scored pain at a significantly higher level than their male colleagues. Fifty-eight percent of respondents considered their knowledge in the area of assessment and treatment of pain was adequate.

CONCLUSIONS: This survey was considered representative of veterinarians working in companion animal practice in New Zealand. Results indicated a relatively high use of peri-operative analgesia, including both pre-emptive and multi-modal analge- sia, in cats and dogs, although there was still some disparity between the perception of how painful a procedure was and the consequent use of pain relief.

CLINICAL RELEVANCE: The establishment of current attitudes and practices indicates to practising veterinarians how their own use of analgesics compares with that of their colleagues. It also provides information to educators on potential areas of focus, given that 42% of respondents felt their knowledge in the area of assessment and treatment of pain was inadequate.     

Granulomatous lesions in lymph nodes of slaughter pigs bacteriologically negative for Mycobacterium avium subsp. avium and positive for Rhodococcus equi

The prevalence of granulomatous lesions in lymph nodes of pigs was studied. From January till August 2004 in two slaughterhouses in The Netherlands 2,116,536 pigs were examined for the presence of granulomatous lesions in the sub-maxillary lymph nodes. In 15,900 (0.75%) of these pigs, lesions could be detected. Nine farms with the highest incidence of lesions were selected for a more detailed pathological and bacteriological examination. On these farms, the prevalence of lesions in sub-maxillary lymph nodes ranged from 2.3 to 5.7% with a mean of 3.0%. From 1276 pigs that were sampled, 98 (7.7%) displayed granulomatous lesions in the sub-maxillary lymph nodes and one (0.1%) pig showed lesions in its mesenteric lymph node. Mycobacterium avium subsp. avium (MAA) could not be isolated from the lymph nodes of the 99 pigs with lesions and from a selection of lymph nodes (n = 61) of pigs without lesions. Rhodococcus equi was isolated from 44 out of 98 (44.9%) of the sub-maxillary lymph nodes with granulomatous lesions and from two mesenteric lymph nodes without lesions. A comparison of former studies and the current results indicate that the prevalence of MAA infections in slaughter pigs has strongly decreased over the last decade, whereas R. equi is highly prevalent. The high incidence of granulomatous lesions associated with the bacteriological presence of R. equi could be considered as a serious cause of misdiagnosis of MAA infections in cases where meat inspection is carried out by inspection for granulomatous changes of lymph nodes only.     

Detecting reproductive system abnormalities of broiler breeder roosters at different ages

The objective of this study was to detect the reasons of rooster's fertility decrease at 50 weeks of age. Therefore, the reproductive system of broiler breeder roosters was laparoscopic, macroscopic and histopathology evaluated, and a comparison of the anatomical aspect with the sperm analysis and birds’ age was realized. Cobb roosters (n = 59) were distributed into two groups (30 and 50 weeks). Evaluations were performed with laparoscopy, macroscopy and histopathology, and seminal quality, blood serum testosterone concentration and weight were also determined. The old roosters presented smaller testicle size, higher intensity epididymal lithiasis and lower testicle sperm production, compared to the young roosters. The use of the endoscope could easily distinguish a normal‐sized testicle than an atrophic one. Four old roosters with severe testicular atrophy did not show spermatogenesis, although three still had sperm in the ejaculate. This would falsely indicate a wrong diagnosis of normal fertility before the testicular atrophy took place. In conclusion, in addition to the weight increase with age, the testicular atrophy and impairment of sperm production seemed to be the main reason to the decrease in the rooster's fertility at 50 weeks of age. Therefore, the use of the laparoscopy as a way to detect the roosters with testicular atrophy before 50 weeks of age and their removal from them flock could be useful as a diagnostic tool to prevent the birds’ fertility loss.     

Administration of exogenous hormones in ovulatory and embryonic response in Pelibuey sheep

The objective of this study was to evaluate the effect of two sources of commercial porcine pituitary‐derived follicle‐stimulating hormone (pFSH) and pFSH—porcine Luteinizing Hormone (pLH), including equine chorionic gonadotropin (eCG), in ovulatory and embryonic response in Pelibuey sheep. Twenty‐four Pelibuey sheep were used and were assigned randomly to four treatments (n = 6): (T1; 200 mg pFSH‐Folltropin^®); (T2; 200 mg pFSH + 300 UI eCG‐Folligon^®); (T3; 250 UI pFSH/pLH‐Pluset^®) and (T4; 250 UI pFSH/pLH + 300 UI eCG). The interval of hours from withdrawal of the device to the beginning of oestrus (BO) was lower (p < .05) in sheep treated with eCG (T2 = 8.0 ± 1.4 and T4 = 10.0 ± 2.8) than in those without eCG (T1 = 12.6 ± 0.6 and T3 = 20.6 ± 2.4). The ovulatory rate (OR) was higher (p < .05) in T1 = 15.5 ± 2.8 and T2 = 15.6 ± 1.4, compared to T3 = 8.1 ± 3.2 and T4 = 11.8 ± 2.8; a significant difference was not shown between them (T1 vs. T2 and T3 vs. T4) when including eCG. The number of non‐fertilized oocytes (NFO) was lower (p ? .05) in T1 = 0.8 ± 0.4 and T3 = 1.8 ± 1.8, compared to those that included eCG (T2 = 6.3 ± 2.4 and T4 = 2.1 ± 1.2). The number of transferable embryos (TE) was higher (p < .05) when FSH was applied (T1 = 5.8 ± 1.1), compared with (T2 = 2.6 ± 1.1, T3 = 2.3 ± 1.4 and T4 = 2.8 ± 1.5). The commercial treatments (pFSH or pFSH‐pLH) in combination with eCG did not improve OR, NFO and TE. However, the exclusive pFSH (Folltropin) treatment presented a higher OR, lower number of NFO and higher number of TE.     

Effect of selenium supplementation on semen characteristics of Brazil's ram

The aim of this study was to investigate the effects of different concentrations of oral supplementation with selenium (Se) upon ram sperm parameters. Thirty rams managed in stall under intensive system were used and divided into five groups (six animals per group) as follows: control group (G1) mineral mixture supplementation without Se, group 2 (G2) mineral mixture supplemented with 5 mg/kg Se, group 3 (G3) supplemented with 10 mg/kg Se, group 4 (G4) supplemented with 15 mg/kg Se and group 5 (G5) supplemented with 20 mg/kg Se. For each group, there was an adjustment period of 14 days. The experimental period was 350 days. Every 56 days, the animals were weighed and semen samples were collected by electroejaculation. Semen analysis included volume, mass moviment, total motility, vigour, concentration and morphology. For plasmatic and acrosomal membrane integrity evaluation and mitochondrial membrane potential were used a combination of fluorescent probes. Differences between means values obtained by analysis of variance were verified by Tukey test with 5% probability. There was no statistical difference between treatment groups in relation to volume, mass moviment, total motility, vigour, concentration, plasma and acrosomal membrane integrity (p > .05). Sperm morphology was different between treatment groups, the G1 (0 mg of selenium) had the highest percentage of major defects (11.11 ± 1.11^a; p < .05). It was concluded that selenium decrease the percentage of sperm defects and did not directly influence on ram sperm volume, mass moviment, total motility, vigour, concentration and membrane integrity.