The diagnosis of freemartinism in cattle using sex-specific DNA sequences.

The majority of heifers born co-twins to bulls are infertile freemartins. It is important that the condition be diagnosed at an early age as freemartins have no potential for use as replacement stock. A rapid, robust, reliable technique for freemartin diagnosis is described. Three Y-specific polymerase chain reaction (PCR) primer pairs: BOV97M, BRY.1 and AMX/Y were used to detect male cells in the blood of heifers born co-twins to bulls. PCR -based tests have advantages over currently used methods of freemartin diagnosis.     

Length‐based assessment of larval lamprey population structure at differing spatial scales

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Application of ozone in grain processing

Ozone is an effective fumigant for insect killing, mycotoxin destruction and microbial inactivation which has a minimal or no effect on grain quality. Studies have demonstrated that ozone which is a natural agent, may offer unique advantages for grain processing along with addressing growing concerns over the use of harmful pesticides. This paper focuses on the efficacy of ozone for preservation of food grains and discusses the possible effects on product quality. Inactivation mechanisms for micro-organisms and mycotoxins are detailed. Critical intrinsic and extrinsic factors governing inactivation are discussed along with potential grain applications.     

Habitat overlap of juvenile and adult lake trout of Great Bear Lake: Evidence for lack of a predation gradient?

A range of organisms, from plankton to fish, commonly shift their habitat distributions horizontally or vertically due to predation risk. Juvenile lake trout, Salvelinus namaycush, are generally viewed as occupying deep areas of lakes to decrease predation pressure from adults. In contrast, we found that juvenile lake trout from Great Bear Lake, NT, Canada, occupied a variety of habitats and from shallow to deep depths (0–150 m), overlapping with adult lake trout. No evidence occurred for a length depth‐based segregation (e.g., ontogenetic shift). Genetic variation was also similar among juveniles in the different depth zones. However, isotopic niches and C:N ratios among juveniles showed some variability in niche widths and positions for individuals caught from the 51–150 m zone compared to juvenile individuals caught from 0–20 m and 21–50 m zones. The uniformly distributed adult lake trout in Great Bear Lake may evenly distribute predation pressure (including cannibalism) across shallow‐ and deep‐water habitats more than in other lakes. As a result, juveniles may respond to differences in foraging opportunities rather than predation risks. Juvenile lake trout did not appear to conform to the general pattern of juveniles seeking a deep‐water refuge to reduce predation risks. In contrast, juvenile lake trout of Great Bear Lake displayed broad resource use across all depths and habitats.     

Scanning electron and light microscopy of selected avian strains of Mycoplasma iowae

The morphology of six strains of Mycoplasma iowae was studied at various stages of growth by scanning electron and light microscopy. The six strains, which formerly represented avian mycoplasmal serotypes I, J, K, N, Q, and R, produced filaments and branching filaments, sometimes with centrally or terminally located bulbous swellings. During cell division, the filaments appeared to develop into chains of coccal, coccobacillary, and elongated cells. Mycoplasmas that appeared as chains of cocci under light microscopy were often observed as coccobacillary or fusiform when viewed with scanning electron microscopy. The morphology of single or paired cells of all strains included cocci, rods, coccobacilli, and pleomorphic forms. Fusiform and teardrop-shaped cells with bleb-like structures were also observed. Some cells of all strains deteriorated by the latter growth stages, forming clumps of flattened irregular-shaped cells, sometimes intertwined with fragmented filaments. The formation of filaments, branching filaments, and the other cell morphology indicated that the six strains of M. iowae were similar in morphology and growth characteristics.     

Bovine post-parturient haemoglobinuria: effect of inorganic phosphate on red cell metabolism

Washed red blood cells from normal cows were incubated as 10 and 20 per cent suspensions in media containing 0, 2.5 and 25 mM phosphate. The results showed that the rate of glycolysis was dependent on the inorganic phosphate concentration. In the absence of phosphate, the consumption of glucose and the production of 2,3-diphosphoglycerate, lactate and adenosine 5'-triphosphate (ATP) were decreased. Incubation without added phosphate also greatly increased the production of fructose-1,6-diphosphate, glyceraldehyde-3-phosphate and dihydroxyacetone phosphate. Moderate hypophosphataemia was induced in two pre-ruminant calves. Washed red cells from the blood of these animals showed a depletion of ATP when compared with red cells from a control calf. The results indicate that phosphorus deficiency, leading to hypophosphataemia, may be a mechanism of post parturient and related syndromes of haemoglobinuria by decreasing red cell glycolysis and resultant ATP synthesis. Subnormal concentrations of ATP would predispose red cells to altered structure and function, a loss of normal deformability, and an increase in fragility and haemolysis with resultant haemoglobinuria.     

The nutritional status of pregnant and non-pregnant mares grazing South East Queensland pastures

It has been reported that the increasing nutritional demands from mid to late pregnancy of grazing mares may not be met when these stages of gestation coincide with pastures being affected by frost. It was established in this study that grass/legume pastures could support the nutritional requirements of brood mares by providing digestible energy intakes of 68.0 and 91.7 MJ/day and digestible nitrogen intake of 91.2 and 138 g/day during mid and late pregnancy, respectively.     

Suspected myelodysplastic/myeloproliferative neoplasm in a feline leukemia virus‐negative cat

A 10‐year‐old castrated Domestic Short‐Haired cat was presented to a primary care veterinarian for a wellness examination and laboratory examination for monitoring of diabetes mellitus. The CBC revealed marked thrombocytosis, leukopenia and macrocytic, normochromic anemia. The cat tested negative for FeLV and feline immunodeficiency virus, but was positive for Mycoplasma haemominutum by PCR. Hematologic abnormalities were not responsive to therapy, so a repeat CBC and a bone marrow aspiration for cytology were performed. Additional blood smear findings included anisocytosis with megaloblastic erythroid precursors, large platelets, eosinophilic myelocytes and metamyelocytes, and rare unidentified blasts. The bone marrow smear was highly cellular, and the cytologic pattern was consistent with myelodysplastic syndrome with an erythroid predominance. At that time, 15% blasts were present. The cat was treated with a vitamin K₂ analog, doxycycline, and prednisolone, but without a clinical response. Within 3 months, euthanasia was elected due to declining quality of life, and a necropsy was performed. Postmortem bone marrow smears were highly cellular and dominated by monomorphic blasts of unknown line of origin (52%), persistent marked erythroid and megakaryocytic dysplasia, and ineffective erythropoiesis and granulopoiesis. Immunohistochemical, immunocytochemical, and cytochemical stains resulted in a diagnosis of acute myeloid leukemia of unclassified type. Additional histologic findings included mixed hepatitis with trematode infestation and lymphoplasmacytic interstitial nephritis with fibrosis. The marked thrombocytosis with myelodysplastic syndrome and the FeLV‐negative status of this cat were unusual. The difficulty in classifying the myelodysplasia and subsequent leukemia highlights a need for further reporting and characterization of these types of disease.