title: Effects of naloxone on calcium turnover in cows affected by milk fever.
abstract: Milk fever is a metabolic disorder of calcium homeostasis that affects about 2 to 6% of postpartum cows. Current therapy is based on the administration of calcium gluconate. On the basis of the clinical signs, and given that endorphins increase at parturition, we supposed that endogenous opioid peptides (EOP) could be responsible for this pathology. In this study, cows with milk fever were administered the opiate antagonist, Naloxone (Nx; experiment 1) or Nx with calcium salts (experiment 2). In experiment 1, Nx induced the recovery of affected cows. The effects of Nx therapy, expressed in terms of proportion of recovered cows, of cows recovering in less than 30 min and cows requiring repeated treatments, were not statistically different than those obtained by means of calcium administration (17/17, 100%; 10/17, 59% and 7/17, 41% vs. 33/35, 94%; 22/35, 63% and 11/35, 31%, respectively; NS). In experiment 2, a significantly higher ratio of cows recovered in less than 30 min in the group of animals treated with Nx in association with calcium salts, compared with the group of cows treated with the calcium traditional therapy (106/118, 90% for calcium-Nx treated cows vs. 34/62, 55% for calcium-treated cows). Moreover, in the group of cows treated with calcium-Nx, the number of cows requiring repeated treatments was significantly reduced and no unrecovered cows were observed. The results support the idea that high EOP levels interfere with inward movement of calcium through the cell membrane and with calcium activity. The association of calcium and Nx at low dosage is a safe method to treat milk fever in cows and reduces muscular complications.
authors.affiliation: Department of Veterinary and Agroalimentary Sciences, Faculty of Veterinary Medicine, University of Teramo, Italy.
authors.forename: R L
authors.initials: RL
authors.lastname: Sciorsci
authors.forename: M E
authors.initials: ME
authors.lastname: Dell'Aquila
authors.forename: P
authors.initials: P
authors.lastname: Minoia
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002136:Calcium, Dietary / Q000008:administration & dosage / Q000493:pharmacokinetics; D002417:Cattle / Q000378:metabolism / Q000502:physiology*; D005260:Female; D009270:Naloxone / Q000494:pharmacology*; D009292:Narcotic Antagonists / Q000494:pharmacology*; D010319:Parturient Paresis / Q000188:drug therapy* / Q000378:metabolism; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000378:metabolism*
chemical_list: D002136:Calcium, Dietary; D009292:Narcotic Antagonists; D009270:Naloxone; D002118:Calcium