Fish meal supplementation increases bovine plasma and luteal tissue omega-3 fatty acid composition

The objective of this experiment was to determine if dietary inclusion of fish meal would increase plasma and luteal tissue concentrations of eicosapentaenoic and docosahexaenoic acids. Seventeen nonlactating Angus cows (2 to 8 yr of age) were housed in individual pens and fed a corn silage-based diet for approximately 60 d. Diets were supplemented with fish meal at 5% DMI (a rich source of eicosapentaenoic acid and docosahexaenoic acid; n = 9 cows) or corn gluten meal at 6% DMI (n = 8 cows). Body weights and jugular blood samples were collected immediately before the initiation of supplementation and every 7 d thereafter for 56 d to monitor plasma n-3 fatty acid composition and BW. Estrous cycles were synchronized using 2 injections of PGF(2α) administered at 14-d intervals. The ovary bearing the corpus luteum was surgically removed at midcycle (between d 10 and 12) after estrus synchronization, which corresponded to approximately d 60 of supplementation. The ovary was transported to the laboratory, and approximately 1.5 g of luteal tissue was stored at -80°C until analyzed for n-3 fatty acid content. Initial and ending BW did not differ (P > 0.10) between cows supplemented with fish meal and those with corn gluten meal. Plasma eicosapentaenoic acid was greater (P < 0.05) beginning at d 7 of supplementation and docosahexaenoic was greater (P < 0.05) beginning at d 14 of supplementation for cows receiving fish meal. Luteal tissue collected from fish meal-supplemented cows had greater (P < 0.05) luteal n-3 fatty acids and reduced (P < 0.05) arachidonic acid and n-6 to n-3 ratio as compared with tissue obtained from cows supplemented with corn gluten meal. Our data show that fish meal supplementation increases luteal n-3 fatty acid content and reduces available arachidonic acid content, the precursor for PGF(2α). The increase in luteal n-3 fatty acids may reduce PGF(2α) intraluteal synthesis after breeding resulting in increased fertility in cattle.     

Successful treatment of bilateral paecilomyces pyelonephritis in a German shepherd dog

A six‐year‐old female entire German shepherd dog was investigated for polyuria, polydipsia and lethargy. Investigations revealed a mild azotaemia and abdominal ultrasound revealed marked bilateral dilation of the renal pelves with echogenic material and proximal left hydroureter. Urine cytological examination and aspirates from the right renal pelvis revealed mats of fungal hyphae consistent with fungal bezoar formation. Fungal cultures revealed a profuse growth of Paecilomyces variotii. Initial treatment with oral itraconazole was unsuccessful, leading to bilateral nephrotomies to remove the fungal material. Postoperatively the Paecilomyces infection persisted despite continued itraconazole therapy. Treatment was commenced with amphotericin B, leading to resolution of the dog's clinical signs. To the authors’ knowledge this is the first report of canine Paecilomyces pyelonephritis, without disseminated systemic disease, which documents its successful treatment.     

In vitro activity of ponazuril against Theileria equi

The equid hemoprotozoan parasite Theileria equi is endemic in most regions worldwide. Infection of horses is a cause of significant economic loss due to costs associated with disease and restriction of trade with non-endemic nations. The ability of certain drugs such as imidocarb dipropionate to eliminate persistent T. equi infection and transmission risk is controversial. The anti-protozoal agent ponazuril has been used successfully to treat equine Sarcosystis neurona and Toxoplasma gondii. The hypothesis that ponazuril inhibits replication of T. equi in vitro was tested. T. equi infected equine erythrocyte cultures were treated with ponazuril at multiple concentrations. Cessation of parasite replication was observed over a 5-day period and the degree of inhibition was variable between drug concentrations. Ponazuril inhibited T. equi in erythrocyte culture at all concentrations tested but parasite elimination required at least 500 μg/mL. The high dose of ponazuril required for in vitro inhibition likely limits its ability to control or clear T. equi infection in vivo, however additional research to evaluate related drugs is warranted.     

Standing low-field magnetic resonance imaging in horses with chronic foot pain

Objective Conventional imaging modalities can diagnose the source of foot pain in most cases, but have limitations in some horses, which can be overcome by using magnetic resonance imaging (MRI). However, there are no reports of the MRI appearance and prevalence of foot lesions of a large series of horses with chronic foot lameness. Methods In the present study, 79 horses with unilateral or bilateral forelimb lameness because of chronic foot pain underwent standing low‐field MRI to make a definitive diagnosis. Results Of the 79 horses, 74 (94%) had alterations in >1 structure in the lame or lamest foot. Navicular bone lesions occurred most frequently (78%) followed by navicular bursitis (57%), deep digital flexor tendonopathies (54%) and collateral desmopathy of the distal interphalangeal joint (39%). Effusion of the distal interphalangeal joint was also a frequent finding (53%). Conclusion Low‐field MRI in a standing patient can detect many lesions of the equine foot associated with chronic lameness without the need for general anaesthesia.     

A comparative study of proximal hindlimb flexion in horses: 5 versus 60 seconds

Reasons for performing study: The flexion test is routinely used in lameness and prepurchase examinations. There is no accepted standard for duration of flexion or evidence that interpretation of results would differ with different durations of flexion. Hypothesis: There will be no difference in interpretation of proximal hindlimb flexion for 5 or 60 s. Methods: Video recordings of lameness examinations of 34 client‐owned horses were performed that included: baseline lameness, proximal hindlimb flexion for 60 s, and flexion of the same limb for 5 s. Videos were edited to blind reviewers to the hypothesis being tested. The baseline lameness video from each horse was paired with each flexion to make 2 pairs of videos for each case. Twenty video pairs were repeated to assess intraobserver repeatability. Fifteen experienced equine clinicians were asked to review the baseline lameness video followed by the flexion test and grade the response to flexion as either positive or negative. Potential associations between the duration of flexion and the likelihood of a positive flexion test were evaluated using generalised linear mixed models. A kappa value was calculated to assess the degree of intraobserver agreement on the repeated videos. Significance level was set at P<0.05. Results: Proximal hindlimb flexion of 60 s was more likely to be called positive than flexion of 5 s (P<0.0001), with the likelihood of the same interpretation 74% of the time. The first flexion performed was more likely to be called positive than subsequent flexions (P = 0.029). Intra‐assessor agreement averaged 75% with κ= 0.49. Conclusions: Proximal hindlimb flexion of a limb for 5 s does not yield the same result as flexing a limb for 60 s. Potential relevance: Shorter durations of flexion may be useful for clinicians that have good agreement with flexions of 5 and 60 s.     

Comment on "The illusion of invariant quantities in life histories"

Nee et al. (Reports, 19 August 2005, p. 1236) used a null model to argue that life history invariants are illusions. We show that their results are largely inconsequential for life history theory because the authors confound two definitions of invariance, and rigorous analysis of their null model demonstrates that it does not match observed data.     

Determining the longer term decline in plant‐available soil phosphorus from short‐term measured values

Once phosphorus (P) applications stop, it is important to know how long it will take for plant‐available P in soil to decline to a particular level for soils with a history of intensive management. The rate of decline in the absence of applied P can be expressed as a half‐life, that is the time in years for it to halve relative to the lowest level measured in the soil. This knowledge is essential when planning long‐term policies for managing the P status of soils. It is important to farmers who wish to optimize applications of P fertilizers and make better use of accumulated P residues to ensure that plant‐available P does not fall below the critical level for the soil and crop because of the risk of losing yield and the inefficient use of other inputs, especially N fertilizer. Lower levels of plant‐available P are also desirable for environmental and ecological reasons. Allowing plant‐available P to decline to the critical level from unnecessarily high concentrations will reduce the risk from P on eroded soil causing adverse effects of eutrophication in surface water. Low levels of plant‐available P are usually considered necessary for establishing species‐rich grassland. A method for determining the longer term decline in plant‐available soil P from short‐term measured values is presented.