Monitoring chronic infection with a field strain of Aleutian mink disease virus

Aleutian mink disease virus (AMDV) readily spread within farmed mink and causes chronic infections with significant impacts for welfare and economy. In the present study a currently circulating Danish AMDV strain was used to induce chronic experimental infection of farmed mink.PCR was used to detect viral DNA in full blood, organs, faeces and oro-nasal swabs weekly for the first 8 weeks and then biweekly for another 16 weeks after AMDV challenge inoculation of wild type mink. The mink (n = 29) was infected and seroconverted 2–3 weeks after AMDV inoculation and AMDV antibodies persisted during the maximum experimental period of 24 weeks. Viraemia and faecal excretion of viral DNA was detected in the mink (n = 29) at various and intermittent time intervals. Excretion of viral DNA in oro-nasal swabs was detected for 1–8 weeks in 21 mink. This highlights the risk of transmitting AMDV between infected farms.PCR was successfully used to detect viral DNA in organs 8, 16 and 24 weeks after AMDV inoculation with only minor differences between these weeks which is of diagnostic interest.This AMDV challenge model was also used to mimic natural infection of susceptible sapphire mink. Four of 6 sapphire mink were infected indirectly via the AMDV inoculated wild type mink whereas the other 2 sapphire mink remained uninfected.     

Experimental infection of pregnant cows with Bacillus licheniformis bacteria.

To study the abortifacient potential and fetoplacental tropism of Bacillus licheniformis bacteria, eight cows in the sixth to eighth month of gestation were inoculated intravenously either once (n = 4) or on four successive days (n = 4) with B. licheniformis at doses ranging from 10(9) to 10(12) colony-forming units. Cows were euthanatized and necropsied prior to abortion (n = 2), at the time of abortion (n = 2), or at calving (n = 4). Live-born calves (n = 5) were euthanatized immediately after delivery and necropsied. B. licheniformis was reisolated from placentomes/endometrium in six of eight (75%) cows and from one fetus aborted 43 days after inoculation. Lesions associated with B. licheniformis were restricted to the pregnant uterus, with the exception of one cow, which developed pneumonia. Necrosis in the fetal compartment of the placenta were present in three of four (75%) cows of both inoculation groups. Lesions were mainly restricted to fetal membranes and especially to the fetal side of the placentomes. Necrosis and diffuse neutrophil infiltrations of both villi and intervillous areas occurred in the fetal part of the placenta, and the placentomal interface was distended by bacteria, neutrophils, erythrocytes, and debris. Within trophoblasts, bacteria were located both free in the cytoplasm and in cytoplasmatic vesicles. Inflammation was present in three of eight (38%) calves. Placental and fetal lesions were similar to those found in cases of spontaneous abortions associated with B. licheniformis. The abortifacient potential of B. licheniformis and the tropism for the bovine placenta is demonstrated here for the first time.     

Potential of Kochia prostrata and Perennial Grasses for Rangeland Restoration in Jordan

Six varieties of forage kochia (Kochia prostrata [L.] Schrad.), two Atriplex shrubs native to North America, and four drought-tolerant perennial grass varieties were seeded and evaluated under arid rangeland conditions in Jordan. Varieties were seeded in December 2007 and evaluated in 2008 and 2009 at two sites. Conditions were dry with Qurain receiving 110 mm and 73 mm and Tal Rimah receiving 58 mm and 43 mm of annual precipitation during the winters of 2007/2008 and 2008/2009, respectively. Plants were more abundant and taller (P < 0.001) at Qurain than Tal Rimah in 2008. Forage kochia frequency was 48% and 30% in 2008 at Qurain and Tal Rimah, respectively. However, no seeded plants were observed at Tal Rimah in 2009, suggesting that 58 mm and 43 mm of annual precipitation are insufficient to allow plants to persist over multiple years. At the wetter site, forage kochia abundance in 2009 was similar (P = 0.90) to that observed in 2008 and plant height increased (P < 0.001) from 2008 (14.4 cm ± 1.1 SE) to 2009 (38.4 cm ± 1.1 SE). Sahro-select and Otavny-select were the most abundant forage kochia varieties (P < 0.05), suggesting that these experimental lines could be more adapted to the environmental conditions of Jordan than the commercially available cultivar Immigrant. Frequency of perennial grass varieties declined (P < 0.001) at Qurain from 82% ± 4 SE to 39% ± 4 SE between 2008 and 2009, respectively. Among grasses, Siberian wheatgrass had better stands than crested wheatgrass, with Russian wildrye being intermediate. Based on this study, forage kochia appears to have great potential for establishing palatable perennial shrubs in arid rangeland conditions in Jordan if annual precipitation is at least 70 mm. Arid-adapted perennial grass varieties might also be useful in rangeland restoration if annual precipitation is over 100 mm.     

Comparison of lameness outcomes in horses with acute or chronic digital lameness that underwent magnetic resonance imaging

ABSTRACT

Aims: To compare the outcome, in terms of lameness score or return to athletic function, of horses with acute vs. chronic digital lameness that underwent magnetic resonance imaging (MRI) of the distal limb and to compare the proportion of horses that received intra-articular therapy of the distal interphalangeal (DIP) joint and pattern of diagnostic analgesia in these groups.

Methods: This is a retrospective study of horses (n?=?95) with acute (≤12 weeks; n?=?46) or chronic (>12 weeks; n?=?49) digital lameness that underwent MRI of the distal limb from 2009–2016, at two equine referral centres in the USA. Criteria for inclusion in the study were that a majority of lameness localised distal to the fetlock, and that lameness assessments for ≥12 months following MRI could be obtained from the medical record or the owner could be interviewed regarding their horse's athletic function. Outcome was characterised by an improvement score where 2?=?return to work at a previous or higher level or lameness improved by one grade or more, 1?=?return to work at a lower level or lameness improved by less than one grade, and 0?=?did not return to work or lameness grade worsened. Whether horses had received intra-articular therapy of the DIP joint and the pattern of diagnostic analgesia prior to MRI was also obtained from medical records or by interviewing the owner.

Results: There was a difference (p?=?0.004) in the proportion of horses assigned to improvement scores of 0, 1 and 2 between horses with acute or chronic lameness. There was no evidence of a difference in the likelihood of having received intra-articular therapy of the DIP joint prior to MRI between horses with chronic or acute lameness (p = 0.085). Similarly, there was no evidence of a difference in the pattern of diagnostic analgesia prior to MRI between the two groups (p = 0.94). Eighty-two percent of owners of horses with acute and 62% of those with horses with chronic lameness had a positive opinion of the utility of MRI as a diagnostic modality.

Conclusion: In a population of horses with digital lameness undergoing MRI, a difference in the outcome, in terms of lameness score or return to athletic function was identified between horses with acute lameness compared to those with chronic lameness.

Clinical relevance: Horses with digital lameness that undergo MRI when the lameness is acute may have an improved prognosis due to accurate diagnosis and earlier application of appropriate therapy.     

Gonadal Activity in Male and Female Captive Fossas (Cryptoprocta ferox) During the Mating Season

The fossa is an endangered, mongoose-like carnivore species endemic to Madagascar with a breeding season (BS) in the southern hemisphere spring. For the present study, faecal samples of captive fossas were collected for over 1 year for five males and four non-pregnant females, and for two pregnant animals during the reproductive period. The goal was to assess gonadal activity using non-invasive hormone measurements of faecal testosterone (T) and gestagen metabolites using assays previously established in our laboratory and further validated in this study. All study animals were housed in northern hemisphere zoos. In males, the seasonal T metabolite profile revealed a peak in spring (March). High performance liquid chromatography (HPLC) analysis was used to characterize the faecal hormone metabolite composition. The highest immunoreactivity was detected in the position of dihydrotestosterone, whereas native T was not detected. In the two pregnant females, gestagen metabolite concentrations increased 4–9 days after the initial matings and remained elevated throughout gestation with concentrations dramatically higher than those of the non-pregnant females during the BS. In these females, gestagen metabolite analyses did not reveal a seasonal pattern similar to the males. The HPLC-analysis revealed that the major proportion of immunoreactivity was associated with an unknown metabolite, whereas native progesterone was undetectable. The seasonal hormone pattern of male fossas gives proof of the reproductive seasonality of this species.
The elevated 5α-pregnan-3β-ol-20-one levels in pregnant animals allows for the characterization of pregnancy in the fossa based on analysis of faecal steroid metabolite concentrations.     

Effects of sow-crate design on sow and piglet behavior

The effects of sow-crate design on certain behaviors of sows and piglets at farrowing and again approximately 3 wk later were evaluated with a 2 x 2 x 4 factorial arrangement of crate width (narrow [N = 55 cm] or wide [W = 64] between lowest horizontal pipes), length (short [S = 183 cm] or long [L = 198] from rump stop to front gate) and side type (lower side of sow crate "fingered" [F], "bowed" bottom bar 20 cm above the floor [B], or straight bottom bar 20 cm [S20] or 25 cm above the floor [S25]). Farrowing-crate design influenced both sow and piglet behaviors both during and immediately after parturition and during nursing-suckling bouts approximately 3 wk later. Activities of 51 sows and their piglets were videorecorded during and immediately following parturition. Sow-crate design affected neither the interval between births of successive piglets in a litter nor the frequency of standing by the sow during parturition. Latency from birth to first mammary contact (LMC) was greater with S25-sided and S sow crates, and especially with S, W crates. A significant interaction occurred between sow-crate side type and dimensions; LMC was longer when S25 sides were combined with S or W crates. Data on suckling behavior were collected from 113 litters over three successive sucklings approximately 3 wk after farrowing. Sow-crate design had no effect either on the consistency with which a piglet suckled a particular teat or teat pair or on the frequency of multiple-teat use. Piglets maintained fewer functional teats with S, S20 crates. The distribution of functional teats between rows was less symmetric with S crates. Piglets nursed with their bodies over a side bar more frequently with B- and S20-sided crates. The sow permitted her piglets to suckle while she was in a vertical stance more frequently with S and N crates, and especially with S, N crates. Sow-crate design affected important behaviors of sows and piglets both during and immediately after parturition as well as during nursing-suckling bouts about 3 wk later.     

Effects of different concentrations of corn oil, magnesium sulfate, and oat hulls in a porcine ulcerogenic ration.

Two experiments involving 32 growing pigs were conducted to evaluate various concentrations of corn oil, magnesium sulfate, and oat hulls as ameliorants in a high cornstarch-low protein ulcerogenic ration. The pig were slaughtered at the end of the respective feeding periods, and stomachs were evaluated for issue lesions. During a 40-day feeding period, additions of corn oil and of MgSO4 in the rations did not seem to affect development of gastric lesions materially. After a 42-day feeding period, neither 5.0% nor 10.0% concentration of oat hulls in the ration prevented formation of ulcers. Total stomach contents, free gastric HCI, and pH of stomach contents were measured in pigs slaughtered after 3, 6, 9, and 12 hours of fasting. Gastric HCI (mEq/L) differed significantly among pigs fed various rations and increased significantly with length of fasting. The pH of stomach contents did not differ among pigs given various rations, but decreased with length of fasting. Thus, corn oil, MgSO4, or oat hulls did not seem to significantly alter the ulcerogenic character of the high cornstarch-low protein ration.     

The vitamin E distribution in serum, liver, adipose and muscle tissues in the pig during depletion and repletion

This study was designed to examine the storage capacity for vitamin E in liver, adipose tissue and skeletal muscle of growing pigs during a period of supplementation and of depletion. Therefore, biopsy specimens of these tissues and samples of serum were frequently taken from 7 pigs throughout the experimental period. After a 7-week period on a diet highly supplemented with vitamin E (405 mg/kg), a significant increase (p less than 0.001) in the concentration of this vitamin was observed in all tissues sampled. The highest level (102.9 +/- 26.2 mg/kg) was observed in the liver. After 2 days of depletion the concentration of vitamin E in the liver had fallen by 80%, whereas the concentration in the fat and muscle remained unchanged during 1 week of depletion. The serum vitamin E value rose significantly (p less than 0.001) after 1 week on the supplemented diet and then remained at about 7 mg/l throughout the supplementation period and decreased (p less than 0.001) after 2 days on a nonsupplemented diet. Generally, the serum vitamin E levels among growing pigs are between 2 and 3 mg/l. The results show that the serum and liver values were correlated when the serum level was within this range. Moreover, it is clearly demonstrated that the concentrations of vitamin E in serum and liver reflect the immediate nutritional status of the animal, whereas the vitamin concentrations in adipose and skeletal muscle tissue reflect its long-term nutritional history.