BACKGROUND: Loss of calcium around calving can lead to diseases of transition period and reduce animal economic life. Prevention of milk fever and subclinical hypocalcemia is crucial and important in this period. Repeated doses of oral calcium chloride at calving is a method to prevent hypocalcemia and associated complications. ObjectiveS: The objective of this study was to evaluate the influence of oral calcium chloride at calving on serum calcium, phosphorus and magnesium in transitional period of Holstein dairy cows fed with anionic and cationic diets. Methods: Forty-two Holstein dairy cows were randomly divided in 3 groups. Group 1 (n = 14), fed diet with negative DCAD without calcium chloride supplementation. Group 2 (n = 14), fed diet with negative DCAD and supplemented with calcium chloride at calving and 12 h later. Group 3 (n = 14), fed diets with positive DCAD and supplemented with calcium chloride at calving and 12 h later. Blood samples were collected at calving and 6 h and 12 h and 1d, 2 d, 7 d, 14 d, 21 and 28 d after calving. Serum concentrations of Ca, P and Mg were measured by conventional methods. Results: The pattern of changes in serum levels of calcium and magnesium in different groups in different time periods (time × treatment interaction) were different (p<0.0001). Changes in serum phosphorus levels in different time periods were statistically significant (p<0.0001), but its mean was not affected by the treatment groups (p=0.7164).                    ConclusionS: In addition to anionic diets, supplemental calcium chloride should be used to prevent subclinical hypocalcemia in high-producing dairy cows.

Objective—To determine the effects of protamine sulfate on clot formation time and clot strength thromboelastography variables for canine whole blood samples. Animals—Blood samples obtained from 11 healthy dogs. Procedures—Blood samples were collected from jugular veins of dogs into syringes with 3.2% sodium citrate (blood to citrate ratio, 9:1). Blood samples were divided into aliquots, and protamine sulfate was added to various concentrations (0 [control], 22, 44, and 66 μg/mL). Prepared samples were activated with kaolin (n = 8) or not activated (8), CaCl2 was added, and thromboelastography was performed. Reaction time (R), clot formation time (K), rate of clot formation (α angle), and maximum amplitude (MA) were measured. Results—For kaolin-activated and nonactivated blood samples, protamine (66 μg/mL) significantly increased R and K and decreased α angle and MA, compared with values for control samples. Also, protamine (44 μg/mL) decreased MA in nonactivated blood samples and increased K and decreased α angle in kaolin-activated samples, compared with values for control samples. Conclusions and Clinical Relevance—Results indicated protamine prolonged clot formation time and decreased overall clot strength in a dose-dependent manner; such effects may contribute to a hypocoagulable state in dogs. Kaolin-activated and nonactivated blood samples were appropriate for measurement of the effects of protamine on coagulation. Administration of protamine to reverse the effects of heparin should be performed with caution.

OBJECTIVE To evaluate 2 processing methods (commercial kit vs conical tube centrifugation) for preparing platelet rich plasma (PRP) for use in llamas and alpacas. SAMPLES Blood samples (30 mL each) aseptically collected from 6 healthy llamas and 6 healthy alpacas. PROCEDURES PRP was prepared from blood samples by use of a commercial kit and by double-step conical tube centrifugation. A CBC was performed for blood and PRP samples. Platelets in PRP samples were activated by means of a freeze-thaw method with or without 23mM CaCl2, and concentrations of platelet-derived growth factor-BB and transforming growth factor-β1 were measured. Values were compared between processing methods and camelid species. RESULTS Blood CBC values for llamas and alpacas were similar. The commercial kit yielded a significantly greater degree of platelet enrichment (mean increase, 8.5 fold vs 2.8 fold) and WBC enrichment (mean increase, 3.7 fold vs 1.9 fold) than did conical tube centrifugation. Llamas had a significantly greater degree of platelet enrichment than alpacas by either processing method. No difference in WBC enrichment was identified between species. Concentrations of both growth factors were significantly greater in PRP samples obtained by use of the commercial kit versus those obtained by conical tube centrifugation. CONCLUSIONS AND CLINICAL RELEVANCE For blood samples from camelids, the commercial kit yielded a PRP product with a higher platelet and WBC concentration than achieved by conical tube centrifugation. Optimal PRP platelet and WBC concentrations for various applications need to be determined for llamas and alpacas.

OBJECTIVE To evaluate species differences and effects of storage duration and temperature on the anticollagenase efficacy of canine, feline, and equine serum on in vitro corneal degradation. SAMPLES Corneas and serum from dogs, cats, and horses. PROCEDURES Clinically normal corneas from dogs, cats, and horses were harvested within 2 hours after euthanasia. Serum samples from dogs, cats, and horses were collected and pooled by species. Corneal specimens were incubated with collagenase derived from Clostridium histolyticum, 5mM calcium chloride in saline (0.9% NaCl) solution, and feline, canine, or equine serum that had been stored for 0, 30, 90, or 180 days at −20° or −80°C. Following incubation, the corneal weight loss percentage and hydroxyproline concentration in the incubation fluid were calculated and compared among experimental combinations. RESULTS Feline serum was more effective than canine or equine serum for minimizing corneal weight loss. Incubation with feline or equine, but not canine, serum significantly reduced hydroxyproline production. Serum storage duration did not affect corneal weight loss, but the hydroxyproline concentration was greater for corneal specimens that were incubated with serum that was stored for 90 days, compared with that for corneal specimens incubated with serum that was stored for 0, 30, or 180 days. Serum storage temperature did not affect corneal weight loss or hydroxyproline concentration. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that serum reduced corneal degradation in vitro, and the duration and temperature at which serum was stored did not affect its anticollagenase efficacy.

Avian influenza outbreaks have occurred during winter months, and effective disinfection of poultry premises at freezing temperatures is needed. The commercial disinfectants Virkon and Accel, supplemented with an antifreeze agent [propylene glycol (PG), methanol (MeOH), or calcium chloride (CaCl2)], were evaluated for their effectiveness in killing avian influenza virus (AIV) at −20°C or 21°C. An AIV suspension was applied to stainless steel disks, air-dried, and covered with a disinfectant or antifreeze agent for 5 to 30 min. Virkon (2%) and Accel (6.25%) with 30% PG, 20% MeOH, or 20% CaCl2 inactivated 6 log10 AIV within 5 min at −20°C and 21°C. At these temperatures PG and MeOH alone did not kill AIV, but the 20% CaCl2 solution alone inactivated 5 log10 AIV within 10 min. The results suggested that CaCl2 is potentially useful to enhance the effectiveness of disinfection of poultry facilities after outbreaks of AIV infection in warm and cold seasons.

Objective—To characterize the dynamics of calcitonin secretion in response to experimentally induced hypercalcemia in cats. Animals—13 healthy adult European Shorthair cats.Procedures—For each cat, the calcitonin response to hypercalcemia (defined as an increase in ionized calcium concentration > 0.3mM) was investigated by infusing calcium chloride solution and measuring circulating calcitonin concentrations before infusion (baseline) and at various ionized calcium concentrations. Calcitonin expression in the thyroid glands of 10 of the cats was investigated by immunohistochemical analysis. Results—Preinfusion baseline plasma calcitonin concentrations were very low in many cats, sometimes less than the limit of detection of the assay. Cats had a heterogeneous calcitonin response to hypercalcemia. Calcitonin concentrations only increased in response to hypercalcemia in 6 of 13 cats; in those cats, the increase in calcitonin concentration was quite variable. In cats that responded to hypercalcemia, calcitonin concentration increased from 1.3 ± 0.3 pg/mL at baseline ionized calcium concentration to a maximum of 21.2 ± 8.4 pg/mL at an ionized calcium concentration of 1.60mM. Cats that did not respond to hypercalcemia had a flat calcitonin-to-ionized calcium concentration curve that was not modified by changes in ionized calcium concentration. A significant strong correlation (r = 0.813) was found between the number of calcitonin-positive cells in the thyroid gland and plasma calcitonin concentrations during hypercalcemia. Conclusions and Clinical Relevance—Healthy cats had very low baseline plasma calcitonin concentrations. A heterogeneous increase in plasma calcitonin concentration in response to hypercalcemia, which correlated with the expression of calcitonin-producing cells in the thyroid, was identified in cats.