Quantification of pericaudal adipocyte diameter in dairy cattle during peripartum: a complementary method to study energetic status using conventional histology.

The energetic status of high-yielding Holstein-Friesian dairy cattle was studied during peripartum under field conditions using body condition score (BCS), glycemia, seric ß-hydroxybutyrate and adipose tissue cellularity. This last method was tested as a complementary tool for energetic status assessment. Biopsies of pericaudal subcutaneous adipose tissue were obtained from 25 multiparous animals at 28 days before and 21 days after parturition. Samples were routinely processed for histological examination and stained with haematoxylin and eosin (H&E). The mean diameter of adipocytes (MDA) was measured with the aid of a digital image processor. During the same period, blood samples were collected weekly for metabolite determinations. The MDA at 28 days pre-partum and 21 days post-partum were 72.1 vs. 66.2 µm respectively (p = 0.055), and the corresponding BCS at these moments was 3.32 vs. 3.19 (p = 0.068). At -28 days pre-partum, the BCS was positively correlated with MDA (Pearson's r = 0.521, p = 0.016) and with glycemia (Pearson's r = 0.404, p = 0.056). Correlations between BCS and MDA, and between BCS and glycemia, with ß-hydroxybutyrate although not significant, suggest that routine histological preparations of biopsies from subcutaneous adipose tissue could be included as an easy and valuable tool for research purposes to evaluate metabolic adaptation of dairy cows to peripartum, as well as the incidence of metabolic disorders and productive performance.

Calbindin D28k expression and the absence of apoptosis in the cerebellum of Solanum bonariense L-intoxicated bovines.

Solanum bonariense intoxication is characterized by cerebellar neuronal vacuolation, degeneration, and necrosis. Cerebellar Purkinje cells seem especially susceptible, but more research is needed to determine the pathogenesis of neuronal necrosis and the mechanism of Purkinje cell susceptibility. Calbindin D28k (CbD28k) is highly expressed in Purkinje cells and has been used as a marker for normal and degenerative Purkinje cells. The goal of this study was to describe S bonariense-induced disease by ascertaining Purkinje cell-specific degenerative changes using CbD28k expression and to correlate this with apoptosis in Purkinje cells, as determined using TUNEL (transferase-mediated dUTP-biotin nick end-labeling) and ultrastructural changes. In all cases, an increase in both dose and duration of S bonariense intoxication resulted in a decrease in the number of Purkinje cells. CbD28k immunohistochemistry was an excellent marker for Purkinje cells because immunoreactivity did not change in normal or degenerative tissues. This finding suggests that excessive calcium excitatory stimulation does not induce rapid neuronal degeneration and death. As found in previous studies, TUNEL tests and electron microscopy suggest that Purkinje cell degeneration and death are not occurring via an apoptotic process. These findings suggest that S bonariense poisoning induces progressive Purkinje cell death that is not mediated by excitotoxicity or apoptotic activation.

Effects of dietary cation-anion difference on blood cortisol and ACTH levels in reproducing ewes.

Formulation of rations to induce a compensated metabolic acidosis in the post-partum cow has proved a useful strategy for prevention of milk fever. Such acidification improves the ability of the animal to maintain calcium homeostasis by promoting the absorption of calcium from the intestine and mobilization of calcium from the bone. In humans, an acidogenic diet results in mild metabolic acidosis in association with a state of cortisol excess and this increase in plasma cortisol may increase bone catabolism. The objective of our experiment was to induce acidification by anionic salt supplementation and to study the effects of anionic supplementation on plasma cortisol and adrenocorticotropic hormone (ACTH) levels in sheep. Twenty-seven twin-bearing sheep were assigned to two experimental groups and a control group, depending on dietary cation-anion difference (DCAD) (+272.6, -88.9 and +164.5 mEq/kg DM respectively). Sheep assigned to each dietary treatment received their respective rations beginning 6 weeks pre-partum and continuing until 12 days post-partum. Anionic diet induced a non-respiratory systemic acidosis in association with a mild increase in plasma cortisol concentration without changes in plasma ACTH levels. Our data suggest that the mild hypercortisolism observed in sheep fed the anionic diet may not be an effector for bone resorption induced by anionic salts. A mild hypercortisolism of this magnitude may lead to osteoporosis but this might require many years of adrenal hypersecretion while anionic salts are only used during the last weeks of pregnancy.

Suspected lasalocid poisoning in three dogs.

The ionophore lasalocid has been used as a feed additive for broilers chickens and for improving feed efficiency in ruminants. Although dogs appear to be more sensitive to lasalocid intoxication than other species, there is only 1 report in the veterinary literature about lasalocid poisoning in dogs. We describe the clinical signs, treatment and resolution of 3 hunting dogs that developed acute neurological signs consistent with lasalocid poisoning after the consumption of several broilers that had died on a nearby farm.

Atypical presentation of long-term ethylene glycol poisoning in a German shepherd dog.

Ethylene glycol is a common cause of poisoning and death in pets by being converted to more toxic metabolites responsible of many toxic effects, mainly renal damage. The present paper describes an atypical case of ethylene glycol poisoning in a dog due to consumption of small amounts of antifreeze solution over a long period of time, and resulting a renal failure.

Long-term effects of dietary anion-cation balance on acid-base status and bone morphology in reproducing ewes.

The beneficial effects of anionic salts on calcium metabolism have been shown by supplementing rations with such salts during the last 3 weeks of pre-partum. However, there are few reports on the effects of anionic salts supplementation for periods of 4 weeks or longer on acid-base status, mineral metabolism and bone morphology. This study was conducted to evaluate the effects of the long-term dietary supplementation of anionic salts on the acid-base status, plasma minerals concentrations and bone morphology in sheep. Twenty-seven twin-bearing sheep were assigned to two experimental groups and a control group, depending on dietary cation-anion difference (DCAD) (+272.6, -88.9 and + 164.5 mEq/kg DM, respectively). Sheep assigned to each dietary treatment received their respective rations beginning 6 weeks prepartum and continuing until 12 days post-partum. Diets containing anionic salts induced a mild metabolic hyperchloraemic acidosis from 1 week pre-partum to 2 days post-partum that was completely compensated by non-respiratory mechanisms. These changes on acid-base status were accompanied by an increase of plasma ionized calcium levels. Plasma total calcium, phosphorus and magnesium concentrations were not affected by dietary treatment. Parathyroid hormone concentrations were related to the concentration of ionized calcium of plasma and were higher in sheep fed the cationic diet. Plasma osteocalcin levels were increased in sheep fed the anionic diet and cortical bone remodelling occurred in all the animals during late pregnancy in light and electron microscopy observation, but was particularly evident in the sheep fed the anionic diet. Bone turnover might be stimulated because of the role of the bone in buffering systemic acidosis. The data suggest that anionic salts ameliorated calcium metabolism around parturition by increasing bone resorption and the concentration of ionised calcium in plasma, possibly mediated by a mild hyperchloraemic metabolic acidosis induced by the salts.

Zinc poisoning associated with separation anxiety in an Argentinean bulldog.

Separation anxiety in dogs is a complex behavioral syndrome produced by many causes. A hunter 4y-old male Argentinean Bulldog had dental disturbances and gastrointestinal and cutaneous symptoms due to high plasma zinc and low copper and calcium plasma concentration. His behavior made him bite galvanized wire fences in his cage and bunk that contained his food, both of a Zn-containing material. Specific treatment resulted in complete recovery.