Antibiotic treatment of Mycoplasma ovipneumoniae in domestic sheep (Ovis aries): Working at the livestock-wildlife interface in Yukon, Canada.

Domestic sheep (Ovis aries) can carry the bacterium Mycoplasma ovipneumoniae (M. ovipneumoniae) in their upper respiratory tract, often with little effect on health and productivity. However, for bighorn sheep (Ovis canadensis) populations, there is a link between M. ovipneumoniae infection and pneumonia, poor lamb recruitment, and high fatality rate. Because of these outcomes, preventing transmission of M. ovipneumoniae to free-ranging wild sheep has garnered interest from both the livestock and wildlife sectors. We hypothesized that treatment with intranasal and systemic enrofloxacin would reduce the prevalence of M. ovipneumoniae-positive animals in a flock of domestic sheep. Initially, the prevalence decreased in the treated group; but by 34 d post-treatment, the number of M. ovipneumoniae-positive sheep returned to near pretreatment prevalence. Key clinical message: Test-and-slaughter is a method used to reduce the risk of transmission of pneumonia-causing M. ovipneumoniae from domestic sheep and goats to free-ranging wild sheep. In an effort to find an alternative, we used enrofloxacin to treat a flock of M. ovipneumoniae-positive domestic sheep; however, long-term reduction of M. ovipneumoniae prevalence in the flock was not achieved.

Traitement antibiotique de Mycoplasma ovipneumoniae chez le mouton domestique (Ovis aries): travail à l'interface bétail-faune au Yukon, Canada. Les moutons domestiques (Ovis aries) peuvent être porteurs de la bactérie Mycoplasma ovipneumoniae (M. ovipneumoniae) dans leurs voies respiratoires supérieures, avec souvent peu d'effets sur la santé et la productivité. Cependant, pour les populations de mouflons d'Amérique (Ovis canadensis), il existe un lien entre l'infection à M. ovipneumoniae et la pneumonie, un faible recrutement d'agneaux et un taux de mortalité élevé. En raison de ces résultats, la prévention de la transmission de M. ovipneumoniae aux moutons sauvages en liberté a suscité l'intérêt des secteurs de l'élevage et de la faune sauvage. Nous avons émis l'hypothèse qu'un traitement par enrofloxacine intranasale et systémique réduirait la prévalence d'animaux positifs à M. ovipneumoniae dans un troupeau de moutons domestiques. Initialement, la prévalence a diminué dans le groupe traité; mais 34 jours après le traitement, le nombre de moutons positifs à M. ovipneumoniae est revenu à une prévalence proche de celle précédant le traitement.Message clinique clé :L'essai et l'abattage sont une méthode utilisée pour réduire le risque de transmission de M. ovipneumoniae, responsable de la pneumonie, des moutons et chèvres domestiques aux moutons sauvages en liberté. Dans le but de trouver une alternative, nous avons utilisé l'enrofloxacine pour traiter un troupeau de moutons domestiques positifs à M. ovipneumoniae; cependant, aucune réduction à long terme de la prévalence de M. ovipneumoniae dans le troupeau n'a été obtenue.(Traduit par Dr Serge Messier).

Reference intervals for mineral concentrations in whole blood and serum of bighorn sheep (Ovis canadensis) in California.

Whole blood and serum mineral concentrations were measured in diverse bighorn sheep (Ovis canadensis) metapopulations in California, and 90% reference intervals were determined. While there were some statistical differences between median concentrations among the different metapopulations, detected values were generally in good agreement with concentrations reported for other bighorn sheep populations and with reference ranges widely accepted for domestic sheep (Ovis aries). Although median whole blood selenium and serum copper concentrations were within adequate ranges reported for domestic sheep, some metapopulations had substantial numbers of individuals whose concentrations would be considered suboptimal for domestic sheep. There are a number of factors that can influence mineral concentrations in wildlife species such as bighorn sheep and that make the establishment of reference ranges challenging. However, the establishment of mineral reference ranges is important for such species, as their health and productivity are increasingly scrutinized and actively managed.

Historic, pre-European settlement, and present-day contribution of wild ruminants to enteric methane emissions in the United States.

The objectives of this analysis were to estimate historic (pre-European settlement) enteric CH(4) emissions from wild ruminants in the contiguous United States and compare these with present-day CH(4) emissions from farmed ruminants. The analysis included bison, elk (wapiti), and deer (white-tailed and mule). Wild ruminants such as moose, antelope (pronghorn), caribou, and mountain sheep and goat were not included in the analysis because their natural range is mostly outside the contiguous United States or because they have relatively small population sizes. Data for presettlement and present-day population sizes, animal BW, feed intake, and CH(4) emission factors were adopted from various sources. Present-day CH(4) emissions from livestock were from recent United States Environmental Protection Agency estimates. The most important factor determining CH(4) emissions from wild ruminants in the presettlement period was the size of the bison population. Overall, enteric CH(4) emissions from bison, elk, and deer in the presettlement period were about 86% (assuming bison population size of 50 million) of the current CH(4) emissions from farmed ruminants in the United States. Present-day CH(4) emissions from wild ruminants (bison, elk, and deer) were estimated at 0.28 Tg/yr, or 4.3% of the emissions from domestic ruminants. Due to its population size (estimated at 25 million), the white-tailed deer is the most significant present-day wild ruminant contributor to enteric CH(4) emissions in the contiguous United States.

Effects of selenium supplementation and sample storage time on blood indices of selenium status in bighorn sheep.

Periodic pneumonia outbreaks cause large-scale die-offs that threaten the viability of bighorn sheep (Ovis canadensis) populations. Bighorns are highly susceptible to pneumonia, and in some cases this susceptibility may be exacerbated by trace mineral deficiencies. To evaluate responses to injectable selenium supplementation, eight captive bighorn sheep were treated with either an injectable sodium selenite supplement or a saline control. We collected 6-ml blood aliquots before and at 1, 6, and 12 wk posttreatment. We submitted one set of aliquots immediately to measure selenium (Se) and zinc (Zn) concentrations and glutathione-peroxidase (GSH-Px) activity; additional aliquots were held at about 22 C and then submitted at 1, 3, and 7 days postcollection to assess effects of storage on these measures. Neither Se nor GSH-Px were affected by selenite injections. Both Se and GSH-Px demonstrated small linear decays over the 7-day storage period (0.011 ppm/day [SE=0.0027] and 15.78 mmole/l/sec/day [SE=6.88], respectively); in contrast, Zn concentrations in stored samples increased logarithmically (0.35 ppm/day on the natural log scale). Blood Se and GSH-Px were not correlated in sampled bighorns; however, because all values for both measures were within normal limits, lack of correlation did not affect interpretation of these data in our study.