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- Author or Editor: Bahram Dalir-Naghadeh x
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Abstract
Objective—To assess changes in serum concentrations of thyroid hormones associated with selenium deficiency myopathy in lambs.
Animals—35 lambs with selenium deficiency myopathy and 30 healthy lambs.
Procedures—Blood samples were collected via jugular venipuncture from lambs with selenium deficiency myopathy and healthy lambs. Activities of markers of selenium deficiency myopathy (erythrocyte glutathione peroxidase [GSH-Px] and plasma creatine kinase [CK]) and serum thyroid-stimulating hormone (TSH) and total thyroxine (tT4) and total triiodothyronine (tT3) concentrations were assessed; values in affected lambs were compared with those in healthy lambs. Correlations of erythrocyte GSH-Px and plasma CK activities with serum concentrations of TSH, tT4, and tT3 were investigated, and the tT3:tT4 concentration ratio was evaluated.
Results—Compared with findings in healthy lambs, erythrocyte GSH-Px activity, serum tT3 concentration, and tT3:tT4 concentration ratio were significantly decreased and serum concentrations of tT4 and TSH and the activity of plasma CK were significantly increased in affected lambs. Analysis revealed a significant negative correlation in the affected group between erythrocyte GSH-Px activity and each of the following: plasma CK activity (r = −0.443), serum TSH concentration (r = −0.599), serum tT4 concentration (r = −0.577), and serum tT3 concentration (r = −0.621).
Conclusions and Clinical Relevance—Results suggested that notable changes in circulating amounts of thyroid hormones develop in association with selenium deficiency in lambs. Such alterations in thyroid hormone metabolism may be involved in the high incidence of disorders, such as stillbirths and neonatal deaths, in selenium-deficient flocks.
Abstract
Objective—To compare time to loss of consciousness (LOC) and effective maintenance of anesthesia following intraosseous (IO) and IV administration of propofol in rabbits.
Design—Evaluation study.
Animals—24 New Zealand White rabbits.
Procedures—Rabbits were selected to receive IO (n = 6) or IV (6) bolus administration of 1% propofol (12.5 mg/kg [5.67 mg/lb]) only or an identical bolus of propofol IO (6) or IV (6) followed by a constant rate infusion (CRI; 1 mg/kg/min [0.45 mg/lb/min]) by the same route for 30 minutes. Physiologic variables were monitored at predetermined time points; time to LOC and durations of anesthesia and recovery were recorded.
Results—Following IO and IV bolus administration, mean time to LOC was 11.50 and 7.83 seconds, respectively; changes in heart rate, respiratory rate, oxygen saturation (as measured by pulse oximetry), and mean arterial blood pressure values were evident, but findings did not differ between groups. For the IO- and IV-CRI groups, propofol-associated changes in heart rate, oxygen saturation, and mean arterial blood pressure values were similar, and although mean arterial blood pressure decreased significantly from baseline, values remained > 60 mm Hg; respiratory rate decreased significantly during CRI in both groups, but remained higher in the IO-CRI group. Anesthesia and recovery time did not differ between the IO- and IV-CRI groups.
Conclusions and Clinical Relevance—In all evaluated aspects of anesthesia, IO administration of propofol was as effective as IV administration in rabbits. Results suggested that total IO anesthesia can be performed in rabbits with limited vascular access.
Abstract
Objective—To determine associations between rate of fistula formation and parity, lactation period, wound age, wound location, and shape of teat injuries in surgically treated teats in dairy cows.
Study Design—Prospective clinical study.
Animals—106 lactating dairy cows with teat lacerations.
Procedures—Lacerations were classified via shape, location, and age. Associations between potential risk factors and fistula formation were analyzed. Seasonal distribution, type of injured teat, parity, and days in lactation were determined.
Results—Cows with teat injury in their first and second parity had 4.1 times the odds of fistula formation, compared with cows with parity ≥ 3.Teats sutured within 48 to 72 hours of injury had 8.3 times the odds of fistula formation, compared with teats sutured within the first 24 hours. Cows in early lactation stage (first 60 days of lactation) were more susceptible to teat injuries. Occurrence of teat injury was greater at the third, fourth, and fifth parity.
Conclusions and Clinical Relevance—Season, parity, and lactation period were associated with prevalence of teat injury in lactating dairy cows in a range system. Neither the type of suture material used nor the suturing technique was associated with effects on healing of the operated full-thickness teat wounds. Factors such as parity and age of the wound can be associated with delay in the healing process, which may result in fistula formation.
