Effect of air exposure on scallop behaviour, and the implications for subsequent survival in culture

Scallop spat produced for continued culture normally requiretransportation between sites, and the associated stresses may causemortalities. In the present experiment, scallops of 40–55 mm shell heightwere emersed in air for time intervals up to 24 h and their behaviourexamined once re-immersed. Scallops were placed upside-down and thenumber of movements and the cumulative numbers righting in 5 min timeblocks were recorded. The greatest frequency for all behaviouralresponses was found at 15–17 °C in August. Responses were reducedin November and June (9–11 °C) and least at 5 °C in January.All effects of treatment, temperatures and season, and increases in airexposure were significantly different. Following the treatments, mortalitiesafter 10 days in culture was about 10–30% for scallops emersed for 18 and24 h in August and June. Scallops did not show significantly differentbehaviour whether they were emersed upright or inverted. However,scallops emersed at 15 °C had fewer responses than scallops held at <10 °C, so chilling during transport may prolong scallop vitality. Theresults suggest that air exposure >12 h should be avoided. At temperatures>9 °C, behavioural responses may be a simple and effective method toassess vitality which can assist in the management of scallop culture.     

Chemical and sensory quantification of geosmin and 2-methylisoborneol in rainbow trout (Oncorhynchus mykiss) from recirculated aquacultures in relation to concentrations in basin water

Globally, aquaculture systems with water recirculation experience increasing problems with microbial taste and odor compounds (TOCs) such as geosmin and 2-methylisoborneol (MIB). This study investigated the content of geosmin and MIB in water and the flesh of 200 rainbow trouts from eight recirculated aquaculture systems in Denmark. TOC content in the fish flesh was measured by a dynamic headspace extraction method and was evaluated by a sensory panel. The results showed significant correlations between TOC content in water and fish and between chemical analysis and sensory perception. When geosmin exceeded 20 ng/L in the water, 96% of the fish had an intense muddy flavor, but below 10 ng geosmin/L, 18% of the fish (only 3% in special depuration ponds) had an intense muddy flavor. The results indicate that TOC levels <10 ng/L will ensure that a negligible portion of the fish obtains an unpalatable taste and flavor due to TOCs.     

Effects of porcine relaxin on induced parturition in beef heifers

Two-year-old crossbred beef heifers were used to test the effects of porcine relaxin (pRelaxin) alone, or in combination with dexamethasone, on the induction of parturition, the incidence of dystocia, and retained placentas. Effects of treatment on pelvic area, postpartum interval, milk production, colostrum quality, calf birth weight, calf vigor, and calf performance were also evaluated. On Day 275 of gestation, heifers from two fetal-sire groups were randomly assigned to one of four groups in a 2 × 2 factorial design and received: no treatment (controls, N = 19), 20 mg of dexamethasone intramuscularly (im) (n = 22), 5 mg of pRelaxin (3,000 U/mg) im (n = 19), or 20 mg of dexamethasone plus 5 mg of pRelaxin (n = 17). Length of gestation (in days) was less (P < 0.05) in heifers treated with dexamethasone (279.8 ± 1.0) than in controls (286.6 ± 0.9), but was not influenced (P > 0.05) by treatment with pRelaxin. The incidence of retained placentas in heifers treated only with dexamethasone (27.3%) was not reduced by concomitant treatment with pRelaxin (35.3%). Retained placentas were not observed in any control heifers and in only one heifer (5.2%) treated solely with pRelaxin. Ease of calving (1 = unassisted, 5 = abnormal presentation) was not influenced by treatment (P > 0.05), even though birth weights (in kilograms) of calves from heifers treated with dexamethasone (36.4 ± 0.8) were less (P < .01) than those of calves from nondexamethasone-treated heifers (39.2 ± 0.8). Dexamethasone tended to reduce (P < 0.07) calf vigor (1 = healthy and strong, 5 = dead on arrival; 1.48 ± 0.11 vs. 1.18 ± 0.11), but was not (P > 0.05) influenced by pRelaxin. The duration of the postpartum anestrous interval (73.1 ± 1.8 d across groups) and pelvic areas following treatment and parturition were not influenced (P > 0.05) by dexamethasone or pRelaxin. Although determinants of colostrum quality (P < 0.01) and quantity (P < 0.08) of milk produced were influenced by dexamethasone, adjusted 205-d weights of calves did not differ (P > 0.05) among groups. In conclusion, treatment with pRelaxin alone failed to induce parturition or, when combined with dexamethasone, to reduce the incidence of retained placentas.     

Effects of hydrochlorothiazide and diet in dogs with calcium oxalate urolithiasis

OBJECTIVE: To determine whether hydrochlorothiazide (HCTZ) reduces urinary calcium excretion in dogs with calcium oxalate urolithiasis. DESIGN: Original study. ANIMALS: 8 dogs with calcium oxalate urolithiasis. PROCEDURE: 4 treatment protocols were evaluated in each dog (a low calcium, low protein diet designed to prevent calcium oxalate urolith formation with and without administration of HCTZ [2 mg/kg (0.9 mg/lb) of body weight, PO, q 12 h] and a maintenance diet with higher quantities of protein and calcium with and without administration of HCTZ). At the end of each 2-week treatment period, 24-hour urine samples were collected. Blood samples were collected during the midpoint of each urine collection period. Analysis of variance was performed to evaluate the effects of HCTZ and diet on urine and serum analytes. RESULTS: Hydrochlorothiazide significantly decreased urine calcium and potassium concentration and excretion. Hydrochlorothiazide also significantly decreased serum potassium concentration. Compared with the maintenance diet, the urolith prevention diet significantly decreased urine calcium and oxalic acid concentration and excretion. Dogs consuming the urolith prevention diet had significantly lower serum concentrations of albumin and urea nitrogen. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of HCTZ decreased urine calcium excretion in dogs with a history of calcium oxalate urolith formation. The greatest reduction in urine calcium concentration and excretion was achieved when dogs received HCTZ and the urolith prevention diet. Results of this study suggest that the hypocalciuric effect of HCTZ will minimize recurrence of calcium oxalate urolith formation in dogs; however, long-term controlled clinical trials are needed to confirm the safety and effectiveness of HCTZ.     

Oral chromium picolinate and control of glycemia in insulin-treated diabetic dogs

Chromium is an essential dietary trace mineral involved in carbohydrate and lipid metabolism. Chromium is required for cellular uptake of glucose, and chromium deficiency causes insulin resistance. Chromium supplementation may improve insulin sensitivity and has been used as adjunct treatment of diabetes mellitus in humans. In this study, 13 dogs with naturally acquired diabetes mellitus were treated with insulin for 3 months, then with insulin and chromium picolinate for 3 months. Dogs weighing <15 kg (33 lb: n = 9) were administered 200 microg of chromium picolinate PO once daily for I month, then 200 microg of chromium picolinate twice daily for 2 months. Dogs weighing >15 kg (n = 4) received 200 microg of chromium picolinate once daily for 2 weeks, then 200 microg twice daily for 2 weeks, then 400 microg twice daily for 2 months. Type of insulin, frequency of insulin administration, and diet were kept constant, and insulin dosage was adjusted, as needed, to maintain optimal control of glycemia. Mean body weight, daily insulin dosage, daily caloric intake, 10-hour mean blood glucose concentration, blood glycated hemoglobin concentration, and serum fructosamine concentration were not markedly different when dogs were treated with insulin and chromium picolinate, compared with insulin alone. Adverse effects were not identified with chromium picolinate administration. Results of this study suggest that, at a dosage range of 20-60 microg/kg/d, chromium picolinate caused no beneficial or harmful effects in insulin-treated diabetic dogs.     

Treatment of equine glaucoma by transscleral neodymium:yttrium aluminum garnet laser cyclophotocoagulation: a retrospective study of 23 eyes of 16 horses

Contact neodymium:yttrium aluminum garnet (Nd:YAG) laser transscleral cyclophotocoagulation (TSCP) was performed on 23 eyes of 16 horses for treatment of glaucoma. The mean highest preoperative IOP was 51 ± 17 mmHg. Follow-up evaluation was available for 19 eyes 1 day after surgery, 14 eyes from 1 to 2 weeks, 16 eyes from 4 to 6 weeks, 9 eyes from 12 to 16 weeks, and 10 eyes greater than 20 weeks after laser treatment. The mean intraocular pressure (IOP) the day following surgery was 34 ± 13 mmHg. The mean IOP for each follow-up period was: one to two weeks postoperative, 23 ± 9 mmHg; four to six weeks, 24 ± 7 mmHg; 12–16 weeks, 28 ± 10 mmHg; and  20 weeks, 22 ± 9 mmHg. IOP measurements were significantly different from pretreatment values for all follow-up intervals except for weeks 12–16 ( P < 0.05). Treatment success was defined as maintenance of IOP < 30 mmHg. Treatment success was achieved in 93%, 88%, 78%, and 70% of the treated eyes at the 1–2 weeks, 4–6 weeks, 12–16 weeks, and the  20 weeks re-evaluation, respectively. No significant difference was found between the number of eyes visual at presentation (52.2%) and visual at 20 weeks (60%). The most common laser complications were conjunctival hyperemia (21.7%) and corneal ulcers (13.0%). Results of this study indicate that Nd:YAG TSCP is an effective method of controlling IOP and preserving vision in horses with glaucoma. An effective Nd:YAG laser protocol for TSCP in the equine glaucomatous eye is a power setting of 11 W, duration of 0.4 s, applied 5 mm posterior to the limbus at 60 sites, resulting in a total energy dose of 264 J.     

Prophylactic use of decoquinate for infections with Cryptosporidium parvum in experimentally challenged neonatal calves

OBJECTIVE: To evaluate the effect of daily oral administration of decoquinate to neonatal calves experimentally challenged with various numbers of Cryptosporidium parvum oocysts. DESIGN: Clinical trial. ANIMALS: 75 calves. PROCEDURE: Calves were purchased from a commercial dairy during a 5-week period. Calves were housed in individual hutches and fed milk replacer with or without decoquinate (2 mg/kg [0.9 mg/lb per day]). Calves were randomly assigned to treatment and 1 of 5 challenge groups (0, 50, 100, 1000, or 10,000 C. parvum oocysts in 60 mL of saline [0.9% NaCl] solution administered p.o. on the day after arrival). Calves were maintained in the study for as long as 28 days. Calves were clinically assessed for diarrhea and dehydration. Fecal samples were submitted for oocyst enumeration 3 times each week. RESULTS: Treatment did not affect number of days to first watery feces (diarrhea), number of days to first oocyst shedding, or duration of diarrhea or oocyst shedding. Duration of oocyst shedding was significantly associated with challenge dose of oocysts administered to calves and number of days to first oocyst shedding. Duration of diarrhea and number of days to first oocyst shedding were significantly associated with week of arrival and number of days to first watery diarrhea. CONCLUSIONS AND CLINICAL RELEVANCE: Daily treatment with decoquinate at the dosage used in this study did not affect oocyst shedding or clinical signs associated with cryptosporidiosis. However, there was an indication that if the number of oocysts calves received could be reduced, then the duration of oocyst shedding and, hence, environmental loading of C. parvum oocysts could be reduced.