[Show abstract][Hide abstract] ABSTRACT: This study tested the impact of moxidectin at peripartum on nematode fecal egg count (FEC) and clinical parameters on ewes in the high altitude tropical Andes of Colombia. FEC and clinical evaluations were performed on 9 occasions in 43 naturally infected ewes before and during gestation and after lambing. Moxidectin (Mox, 200 µg kg−1) was applied at late pregnancy (T1, n = 15) or 48 hours after parturition (T2, n = 14). 14 untreated ewes served as controls (C). Suckling lambs (n = 58) remained untreated and underwent four clinical and parasitological evaluations until 8 weeks after birth. Mox efficacy equaled 99.3% (T1) and 96.9% (T2). Highest mean FEC value reflecting periparturient nematode egg rise (PPER) was recorded in C ewes at 4–6 weeks after lambing. Significant FEC reductions were found in T1 (94.8%) and T2 (96.7%) ewes (p < 0.05). All lambs showed a significant and ewes-group independent increase in FEC before weaning (p < 0.05). Clinical parameters (anemia and diarrhea) showed time- and treatment-related differences (p < 0.05). Monitoring of FEC and clinical parameters linked to gastrointestinal parasite infections allowed demonstrating that postpartum or preweaning are two critical periods to nematode infection for sheep raised under tropical Andes high altitude conditions. Use of Mox as anthelmintic treatment prevented PPER.
Full-text · Article · Jun 2015 · Veterinary Medicine International
[Show abstract][Hide abstract] ABSTRACT: This prospective study investigated the prevalence, the ocular features and the impact on zootechnic performance of congenital entropion in a sheep flock. A total of 318 Ile de France and Texel purebred and crossbred lambs were observed from birth to the age of 14 days. Repeated ocular examinations were performed and clinical signs were scored at different time points with a three-point severity scale. Spontaneous evolution of ocular clinical signs presented by entropic eyes was then monitored on a weekly basis from the age of 14 days until complete recovery occurred. The impact of entropion on growth was evaluated by measuring the bodyweight and by comparing affected animals with a breed-, gender- and litter size-matched-control group. Fifty-two lambs were affected by entropion. There were no gender-related differences, but significant differences among litter size and breed: triplet lambs, Ile de France and crossbred lambs were significantly more affected by entropion than purebred Texel lambs. The median time after which eyes with entropion recovered spontaneously was 7 days (range 2–42 days). No significant differences were found between groups regarding average daily gain. In conclusion, traits such as litter size and breed did influence the occurrence of congenital entropion in lambs. Moreover, this condition did not impact on lamb growth and resolved spontaneously.
No preview · Article · Apr 2013 · Small Ruminant Research
[Show abstract][Hide abstract] ABSTRACT: Purpose - To determine the prevalence, anatomical location and severity of cartilage defects in the stifle (knee) within a population of adult ewes enrolled for research. Methods - Animals: hind limbs (n= 60) from 30 adult ewes collected within 6 hours of euthanasia. Gross anatomical observation: the articular surfaces of the distal femur, proximal tibia and patella were examined by gross observation by two pairs of investigators. They scored the abnormalities of the hyaline cartilage using OARSI recommendations for ovine cartilage: score 0 for intact cartilage surface; score 1 for surface roughening; score 2 for deeper defects (fibrillation, fissures) not involving the subchondral bone; score 3 for small erosions down to subchondral bone (less than 5 mm diameter); score 4 for large erosions down to subchondral bone (more than 5 mm diameter). Scoring of articular surfaces was performed in 26 anatomic areas in each knee. Discrepancies were discussed between investigators and pairs till a consensus was reached. Histopathology: for each anatomical location where lesions had been identified, osteochondral slabs were obtained for histopathology. Samples were obtained in several regions with negative findings (score 0) for control. Conventional light microscopy [staining with Toluidine Blue and Safranin O) was performed to characterize structure of cartilage and bone, and confirm the classification of lesions performed by gross observation.
Scoring and grading: the most severe lesion observed in each of the 26 anatomic regions was used to score the articular surface of that region. Grading of cartilage defects within each knee was obtained by the addition of the scores of all regions. Results - There were 23 Texel and 7 Iles de France ewes, aged 3 to 11 years, weighting between 38 and 72 kg, euthanized between May and October 2011. There were anatomical locations where cartilage defects were significantly (p < 0.05) more frequently identified than in others: central third of the medial femoral condyle (MFC2), axial aspect of the central third of the medial tibial condyle (AxMTC2), axial aspect of the central third of the lateral tibial condyle (AxLTC2). Score 2 defects were present respectively in 25, 31 and 15 % of all stifles on MFC2, AxMTC2 and AxLTC2 while score 1 surface abnormalities were present in 36, 25 and 5 % respectively. There was no effect of side (left or right), weight or breed on the grade of cartilage defect in the knee. Though not reaching statistical significance, grade increased moderately with age in this population (p = 0.08 and b= 0.02). Conclusions - This study demonstrated that score 2 cartilage defects can be significantly prevalent in stifles in a population of sheep enrolled for research. It indicates that, in Texel and Iles de France used for research, it is useful to assess cartilage status at baseline before including the animal in the experimentation, and to enroll, for each group of the trial, animals presenting either no cartilage defect or a same grade of defect. This should be assessed by non-invasive imaging modalities at baseline. Further research is required to evaluate the development of those lesions over time and compare imaging modalities in their ability to assess naturally occurring cartilage defects in the ovine stifle.
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to determine whether a single dose of an inactivated bluetongue virus serotype 8 (BTV-8) vaccine altered semen quality in rams. Twenty sexually mature rams were assigned to three experimental groups: two groups of four animals were vaccinated and a third group of four animals was unvaccinated. The first group included rams with a history of natural BTV-8 infection in 2007 and the second and third groups included BTV-8 naïve rams. Semen was collected prior to vaccination and for 4months post-vaccination. There were no significant differences in semen quality traits, including motility and concentration of spermatozoa, and percentages of living, normal dead and abnormal dead spermatozoa, between vaccinated and unvaccinated groups, or over time (P>0.05). The BTV-8 vaccine tested in this study did not appear to have any adverse effect on semen quality in rams.
No preview · Article · Feb 2012 · The Veterinary Journal
[Show abstract][Hide abstract] ABSTRACT: This study investigated if viral RNA was detectable in the semen of rams clinically infected with bluetongue virus serotype 8 (BTV-8) by RT-qPCR, and to what extent the amount detected may be predictive of sperm quality. Semen samples were collected on six occasions from 93 BTV-8 infected rams involved in two longitudinal (n=12 and 27, respectively) and one cross-sectional (n=54) field study. Semen quality was assessed in terms of mass motility, concentration of spermatozoa, percentage of living and dead spermatozoa as well as cytological features. An overall semen quality score (SQS) was established. Depending upon the studied population, BTV RNA was detected in 75-100% of semen samples at initial testing 25-57 days post-observation (DPO) of clinical signs, and was detectable up to 116 DPO in a proportion of rams undergoing repeated sampling. Semen quality variables were significantly altered following natural BTV-8 infection and correlated with the amount of BTV RNA present. The SQS did not return to normal when virus was no longer detectable, suggesting that clearance of BTV precedes full recovery of sperm quality. In conclusion, viral RNA may be transiently recovered from the semen of BTV-8 affected rams and may serve as an indicator in predicting ram breeding potential following natural infection.
No preview · Article · Jul 2011 · The Veterinary Journal
[Show abstract][Hide abstract] ABSTRACT: Infection with bluetongue virus serotype (BTV)-8 occurred in ruminants in 2006 in Central-Western Europe. The trans-placental passage of this virus has been demonstrated in naturally- and experimentally-infected cattle and in experimentally-infected sheep. Trans-placental transmission is potentially important in the 'over-wintering' of this virus and its subsequent impact on reproductive performance. This epidemiological study was carried out on a sheep flock in Belgium that had experienced a severe outbreak of BTV-8 infection, and where the seroprevalence had increased from 1.3% to 88% between January and November 2007. In total, 476 lambs and 26 aborted fetuses from 300 ewes, lambing at four distinct time periods, were investigated between November 2007 and May 2008. The following evidence suggested that BTV-8 infection occurred in utero: (1) positive PCR results from splenic tissue from aborted fetuses (n=4); (2) fetal malformations suggestive of BTV infection (n=10); (3) positive PCR results from red blood cells in-lambs (n=7), and (4) the presence of antibody at birth in viable lambs prior to the intake of colostrum (n=9). The evidence provided by this investigation strongly suggests that trans-placental BTV-8 infection occurs in naturally-infected sheep and the impact of infection on the reproductive performance of such a naïve flock was considerable, with up to 25% of ewes aborting and with flock fertility reduced by 50%. The contribution of in utero-infected lambs to the over-wintering of BTV appears limited.
Full-text · Article · Jan 2011 · The Veterinary Journal
[Show abstract][Hide abstract] ABSTRACT: In 2006, bluetongue (BT) virus serotype 8 emerged in northern Europe and numerous ruminants were affected in the following year. Infertility in males is one of the consequences of BT, although its severity and duration after natural infection has not been documented. In this report, the impact of BT-8 on clinical signs and semen quality of naturally infected rams is described through a longitudinal study of two Belgian ram populations (n = 12 and n = 24) and a cross sectional study in a further ram population (n = 43).Macroscopic semen characteristics, semen concentration, motility, percentage of living and dead spermatozoa were assessed in 167 semen samples collected on 1–6 occasions from 79 BT-8 infected rams within 5–138 days after onset of clinical disease. These were compared with healthy control animals. Significant changes in all variables were observed after natural BT-8 infection. Total recovery occurred around 85 days after clinical disease in animals undergoing a close follow-up of semen quality. Good correspondence between the results of the longitudinal and cross sectional studies suggests that semen quality of BT-8 affected rams reached normal references values 63–138 days after clinical diagnosis of BT. In addition, semen concentration seems to be a sound epidemiological indicator of ram semen quality.
No preview · Article · Nov 2009 · The Veterinary Journal