Risk-based surveillance of antimicrobial residues in pigs – Identification of potential risk indicators

Around 20,000 samples are analysed each year for the presence of antibacterial residues in Danish finisher pigs, and between zero and five samples are detected positive above the maximum residue level (MRL). The intention was to develop a risk-based surveillance programme involving fewer samples while ensuring equal sensitivity. Therefore, risk indicators were searched for. Data were obtained from the Danish slaughterhouse database covering the period from July 2010 to December 2012. Residues were found or suspected in 17 incidents. In nine of these, the farmer had called in to prevent the pigs from being slaughtered. Hence, eight suspect cases were found through the surveillance programme, and two of these were above MRL. For these eight case herds, the number of pigs slaughtered and the number in which each of the following lesions were found were included in a statistical analysis: chronic pleuritis, tail bite, chronic pericarditis, chronic pneumonia, chronic peritonitis, osteomyelitis, abscess in hindquarters, abscess in leg/toe and abscess in forequarters. Only chronic pleuritis was associated with the presence of residues. Next, data from all herds delivering pigs for slaughter to the same abattoir were included covering a 3-month period prior to the residue finding. The prevalence of chronic pleuritis was on average 1.7 times higher in the eight case herds compared to all other herds. In two herds, the prevalence was significantly higher (P ≤ 0.05), and in one herd substantially higher, but only borderline significant (P = 0.1). In the remaining herds, the prevalence did not differ from the other herds delivering pigs to the abattoir. This indicates that chronic pleuritis might be considered as a risk indicator for use in surveillance. Other risk indicators/factors – reported in the cases where the farmers called in – were inadequate marking of treated animals and incorrect use of medication dispensers. These factors are not suited for use in surveillance and should be dealt with otherwise.     

Ovine craniofacial malformation: A morphometrical study

Craniofacial malformation in 64 sheep was phenotypically described as mandibular distoclusion. Digital radiographs were examined in order to determine the degree of morphological changes in certain bones of the skull. Therefore, laterolateral standardised digital radiographs were used to determine anatomic reference points. Subsequently, five reference lines were defined and 16 linear and seven angular measurements were determined to describe malformations in the bones of the skull. Statistical analysis revealed a significant shortening of the rostral part of the corpus mandibulae and of the ramus mandibulae. However, the molar part of the mandible remained unchanged. These morphological changes caused premolar and molar malocclusion. No further craniofacial abnormalities, such as an elongation of the maxilla or of the incisive bone, were identified. In conclusion, the phenotypically observed mandibular distoclusion is caused by a shortening of specific parts of the mandible. This form of ovine craniofacial malformation is therefore best described as brachygnathia inferior.     

Screening for periodontal disease in research dogs - a methodology study

Background

It has been shown that the prevalence of both clinical attachment loss (CAL) ≥1 mm and pocket probing depth (PPD) ≥4 mm is relatively high even in younger dogs, but also that only a minority of the dogs have such clinical signs of periodontal disease (PD) in more than a few teeth. Hence, a minority of dogs carry the major PD burden. These epidemiological features suggest that screening for PD in larger groups of dogs, allowing for rapid assessment of treatment planning, or for the selection of dogs with or without PD prior to be included in experimental trials, should be possible. CAL is the central variable in assessing PD extent and severity while PPD is the central variable used in treatment planning which make these two variables obvious in a screening protocol with the dual aim of disease identification and treatment planning. The main purpose of the present study in 98 laboratory Beagle dogs was to construct a fast, simple and accurate screening tool, which is highly sensitive for the identification of dogs with PD.

Results

Examination of the maxillary P4, P3, P2, I1 and C would, in this population, result in the identification of 85.5% of all dogs and 96% of all teeth positive for CAL ≥1 mm, and 58.9% of all dogs and 82.1% of all teeth positive for PD ≥4 mm.Examination of tooth pairs, all C’s, maxillary I2, M2 and the mandibular P4 would, in this population result in identification of 92.9% of all dogs and 97.3% of all teeth positive for PD ≥4 mm, and 65.5% of all dogs and 83.2% of all teeth positive for CAL ≥1 mm. The results presented here only pertain to the present study population.

Conclusions

This screening protocol is suitable for examination of larger groups of laboratory Beagle dogs for PD and our findings indicate that diseased dogs are identified with a high degree of sensitivity. Before this screening can be used in clinical practice, it has to be validated in breeds other than Beagle dogs and in populations with larger age variation.