Segmental axonopathy of Merino sheep in New Zealand

AIM: To investigate an axonopathy of Merino sheep that caused progressive hindlimb ataxia and slight to moderate paresis, with the purpose of understanding its pathogenesis.

METHODS: Tissues were fixed in buffered paraformaldehyde or paraformaldehyde and glutaraldehyde, processed into wax and epoxy resin, respectively, and examined by light and electron microscopy. Fresh frozen spinal cord and trigeminal nerve roots were subjected to homogenisation, centrifugation and two-dimensional electrophoresis. Selected protein spots were identified using matrix-assisted laser desorption ionisation (MALDI) mass spectrometry.

RESULTS. By light microscopy, there were large pale foamy spheroidal axonal swellings affecting peripheral as well as central axons. By electron microscopy, these were shown to contain many membrane-bound vesicles. The main abnormalities in expressed proteins involved cytoskeletal elements and myosin heavy chain, the latter interpreted as associated with the molecular motor myosin Va.

CONCLUSIONS: The disorder is the same as that described in Merinos in Australia as segmental axonopathy, and believed to have an inherited aetiology. The lesions and protein changes indicate abnormalities of the cytoskeleton, its relationship with the myelin sheath, and myosin Va molecular motor. The consequence appears to be abnormal axonal transport and inability to maintain the integrity of axons and their myelin sheaths.     

A possible predisposition to dilated cardiomyopathy in Huntaway dogs

AIM: To compare the prevalence of dilated cardiomyopathy (DCM) in New Zealand Huntaway dogs with the prevalence of DCM in other breeds of dog.

METHODS: The necropsy database at Massey University was used to identify cases of DCM diagnosed between January 1999 and March 2006. Dogs were considered to have DCM if echocardiographic, gross necropsy, or histological findings were consistent with this diagnosis. The prevalence in Huntaways was then compared with the prevalence observed in all breeds of dog, as well as the prevalence observed in large breeds of dog.

RESULTS: Twelve dogs were identified with DCM. One was diagnosed using echocardiography, while the other 11 were diagnosed by gross necropsy examination. The gross diagnosis of DCM was confirmed histologically in 6/11 dogs. The prevalence of DCM in Huntaways was significantly higher than the prevalence seen in all breeds of dog (p=0.008), and the prevalence in large breeds of dog (p=0.025). All four Huntaways diagnosed with DCM were male, and had an average age of 4 years. Three dogs presented with symptoms attributable to impaired heart function while one presented with symptoms of chronic renal failure. The duration of clinical symptoms prior to presentation ranged between 1 day and 3 weeks.

CONCLUSIONS: The results of this study suggest that Huntaways may be predisposed to the development of DCM. Although the increased prevalence in this breed was significant, only small numbers of affected Huntaways were identified, and additional cases are required to confirm these preliminary findings.

CLINICAL RELEVANCE: Huntaways are the most common working dog in New Zealand. The premature loss of a working dog is expected to have a significant economic impact on farmers. Further investigation of DCM in Huntaways may allow measures to reduce the prevalence in this breed.     

Pathogenesis of reproductive failure induced by Trypanosoma vivax in experimentally infected pregnant ewes

The present study was aimed at investigating the effect of experimental infection by Trypanosoma vivax in different stages of pregnancy, determining the pathogenesis of reproductive failure, and confirming transplacental transmission. We used 12 pregnant ewes distributed into four experimental groups: G1, was formed by three ewes infected with T. vivax in the first third of pregnancy (30 days); G2 comprised three infected ewes in the final third of pregnancy (100 days); G3 and G4 were composed of three non-infected ewes with the same gestational period, respectively. Each ewe of G1 and G2 was inoculated with 1.25 × 10⁵ tripomastigotes. Clinical examination, determination of parasitemia, serum biochemistry (albumin, total protein, glucose, cholesterol, and urea), packed cell volume (PCV), serum progesterone, and pathological examination were performed. Placenta, amniotic fluid, blood and tissues from the fetuses and stillbirths were submitted to PCR. Two ewes of G1 (Ewe 1 and 3) presented severe infection and died in the 34^th and 35^th days post-infection (dpi), respectively; but both fetuses were recovered during necropsy. In G2, Ewe 5 aborted two fetuses on the 130^th day (30 dpi) of pregnancy; and Ewe 6 aborted one fetus in the 140^th day (40 dpi) of gestation. Ewes 2 and 4 delivered two weak lambs that died five days after birth. Factors possibly involved with the reproductive failure included high parasitemia, fever, low PCV, body score, serum glucose, total protein, cholesterol, and progesterone. Hepatitis, pericarditis, and encephalitis were observed in the aborted fetuses. The presence of T. vivax DNA in the placenta, amniotic fluid, blood, and tissues from the fetuses confirms the transplacental transmission of the parasite. Histological lesion in the fetuses and placenta also suggest the involvement of the parasite in the etiopathogenesis of reproductive failure in ewes.     

Comparison of Synthetic Oviductal Fluid and G1/G2 Medium under Low‐1 Oxygen Atmosphere on Embryo Production and Pregnancy Rates in Nelore (Bos indicus) Cattle

In this work, we evaluated whether embryo development and pregnancy rates would be affected by culturing bovine Bos indicus embryos in Synthetic Oviductal Fluid with amino acids (SOFaa) or G1/G2 sequential medium under a low‐oxygen atmosphere. Using Ovum Pick Up, we obtained 1,538 oocytes, divided into G1/G2 (n = 783) and SOFaa (n = 755). No difference was observed for blastocyst development among the groups (27.8% ± 14.6 and 34.9% ± 20.0 for G1/G2 and SOFaa respectively, p > 0.05). Transferring the embryos (n = 450) from both groups to recipients resulted in similar pregnancy rates for the G1/G2 (38.4% n = 78/203) compared to the SOFaa (39.7% n = 98/247). Our findings confirm that Bos indicus embryos cultured in SOFaa and G1/G2 under low‐oxygen atmosphere have similar in vitro (blastocyst rate) and in vivo (pregnancy rate) developmental capacity. However, embryos cultured in G1/G2 medium have higher cleavage than those cultured in SOFaa medium.     

Determining the bioavailability of contaminants and assessing the quality of sediments

Background, Aims and Scope  

Our study determined if and when an avoidance or attraction behavioural response would be displayed by Ilyanassa obsoleta when presented with a choice between harbour and reference sediments. Our goal was to develop a non-lethal approach that could be used in future assessments of the environmental quality of field sediments.     

Recovery of soil organic matter,organic matter turnover and nitrogen cycling in a post-mining forest rehabilitation chronosequence

Recovery of soil organic matter, organic matter turnover and mineral nutrient cycling is critical to the success of rehabilitation schemes following major ecosystem disturbance. We investigated successional changes in soil nutrient contents, microbial biomass and activity, C utilisation efficiency and N cycling dynamics in a chronosequence of seven ages (between 0 and 26 years old) of jarrah (Eucalyptus marginata) forest rehabilitation that had been previously mined for bauxite. Recovery was assessed by comparison of rehabilitation soils to non-mined jarrah forest references sites. Mining operations resulted in significant losses of soil total C and N, microbial biomass C and microbial quotients. Organic matter quantity recovered within the rehabilitation chronosequence soils to a level comparable to that of non-mined forest soil. Recovery of soil N was faster than soil C and recovery of microbial and soluble organic C and N fractions was faster than total soil C and N. The recovery of soil organic matter and changes to soil pH displayed distinct spatial heterogeneity due to the surface micro-topography (mounds and furrows) created by contour ripping of rehabilitation sites. Decreases in the metabolic quotient with rehabilitation age conformed to conceptual models of ecosystem energetics during succession but may have been more indicative of decreasing C availability than increased metabolic efficiency. Net ammonification and nitrification rates suggested that the low organic C environment in mound soils may favour autotrophic nitrifier populations, but the production of nitrate (NO₃^?) was limited by the low gross N ammonification rates (≤1 μg N g^?1 d^?1). Gross N transformation rates in furrow soils suggested that the capacity to immobilise N was closely coupled to the capacity to mineralise N, suggesting NO₃^? accumulation in situ is unlikely. The C:N ratio of the older rehabilitation soils was significantly lower than that of the non-mined forest soils. However, variation in ammonification rates was best explained by C and N quantity rather than C:N ratios of whole soil or soluble organic matter fractions. We conclude that the rehabilitated ecosystems are developing a conservative N cycle as displayed by non-mined jarrah forests. However, further investigation into the control of nitrification dynamics, particularly in the event of further ecosystem disturbance, is warranted.     

人工授精使肉猪利润最大化

商业性养猪生产是通过人工授精(AI)来实现的,能对其产生影响的技术即使有,也是极少数.口本养猪生产人员于1947年首次倡导应对猪实行人工授精,然而直到20世纪80年代才得以经常性地应用,从而使遗传学的常规移动可跨越更大的距离.     

Estriolum Treatment in the Bitch: A Risk for Uterine Infection?

Purulent vaginal discharge in a bitch in which ovariohysterectomy has been performed is often caused by inflammation of the uterine stump. The inflammation is due to either cystic endometrial hyperplasia (CEH) induced primarily by progesterone from remnant ovarian tissue or exogenous progestagens, or it is due to the presence of unabsorbed suture material. This report describes a 9-year-old Irish setter with hemopurulent vaginal discharge and non-pruritic symmetrical alopecia, which had undergone ovariohysterectomy 3.5 years ago and which had been treated with estriolum daily for the past 2.5 years because of urinary incontinence. Vaginoscopy revealed hemopurulent discharge throughout the vagina and vestibule. Cytological examination of ultrasound-guided fine-needle aspiration biopsies of a large mass in the hypogastricum, which appeared to be the uterine cervical stump, revealed septic purulent inflammation. The concentration of plasma progesterone was low and the concentration of plasma 17-ß oestradiol did not increase after gonadotrophin-releasing hormone administration. No remnant ovarian tissue was found by abdominal ultrasonography, laparotomy, or histological examination of mesovarian pedicles. Laparotomy revealed uterine stump empyema. Histological examination of the surgically removed mass excluded both CEH and unabsorbed suture material as the cause of the stump empyema. Instead, it is hypothesized that the long-term treatment with estriolum was a causative factor. This suggests that bitches treated with estriolum should be examined regularly.     

Evaluation of a multi‐agent chemotherapy protocol combining dexamethasone,melphalan, actinomycin D,and cytarabine for the treatment of resistant canine non‐Hodgkin high‐grade lymphomas: a single centre's experience

The DMAC protocol (dexamethasone, melphalan, actinomycin‐D, cytarabine) has been evaluated in American studies for the treatment of relapsed canine lymphoma, comparing similarly to other rescue protocols. The aim of this study was to evaluate efficacy and toxicity of DMAC, in a larger UK cohort of resistant canine lymphomas. Medical records of dogs with resistant non‐Hodgkin high‐grade lymphomas that received DMAC as a rescue protocol were reviewed from 2007 to 2017. Response, time from initiation to discontinuation (TTD) and toxicity (Veterinary Cooperative Oncology Group criteria) were assessed. One hundred dogs were included; 86 received CEOP (modified CHOP including epirubicin) as first‐line treatment. Thirty‐five dogs (35%) responded: 21 complete responders (CRs) and 14 partial responders (PRs). Responders had significantly longer TTD (P < 0.001) compared with non‐responders: 62 days (range 28‐952) for CR vs 32 days (range 20‐70) for PR. Six CR received more than six cycles of DMAC (range 7‐36 cycles) and experienced a longer TTD (median 508, range 126‐952 days). Thrombocytopenia occurred in 45% (24 grade 1‐2, 21 grade 3‐4) and neutropenia in 36% of cases (29 grade 1‐2, 7 grade 3‐4). Gastrointestinal toxicity occurred in 42% of dogs (40 grade 1‐2, 2 grade 3‐4). Owing to chemotherapy toxicity, treatment was discontinued in five, and hospitalization required in six cases. In this study, response to DMAC was lower and of generally shorter duration than previously reported. Toxicity was high, but infrequently led to hospitalization or discontinuation of treatment.