title: Effect of subcutaneously released 24F-1,25-dihydroxyvitamin D3 on incidence of parturient paresis in dairy cows.
abstract: Twenty-one aged Jersey cows were fed a high calcium diet prior to parturition to predispose them to parturient paresis. Eleven cows were implanted subcutaneously with pellets containing 24F-1,25-dihydroxyvitamin D3 7 d before the expected date of parturition and thereafter at 7-d intervals until parturition. Ten cows were left untreated to serve as controls. Incidence of parturient paresis among control animals was 80% (8/10). Treatment reduced the incidence of parturient paresis to 9% (1/11). The mean observed plasma calcium concentration nadir of implanted cows was 6.61 +/- .40 mg/dl, which was significantly greater than the plasma calcium nadir of 4.45 +/- .39 mg/dl observed in the control cows. Two steers were implanted with and three nonpregnant, nonlactating cows received intramuscular injections of 24F-1,25 dihydroxyvitamin D3 to contrast circulating plasma concentrations achieved by the two routes. Intramuscular injection and implantation resulted in plasma 24F-1,25 dihydroxyvitamin D3 concentrations above 300 pg/ml for the first 48 h after administration. From d 4 until d 11 after administration, plasma concentration was maintained between 164 and 89 pg/ml in the implanted steers. Plasma concentration was undetectable 7 d after an intramuscular injection. These data indicate that, with refinement, sustained release of 24F-1,25 dihydroxyvitamin D3 can be successfully used to reduce the incidence of parturient paresis.
authors.affiliation: National Animal Disease Center, USDA, Ames, IA 50010.
authors.forename: J P
authors.initials: JP
authors.lastname: Goff
authors.forename: R L
authors.initials: RL
authors.lastname: Horst
mesh_terms: D000818:Animals; D002117:Calcitriol / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood; D002118:Calcium / Q000097:blood; D002136:Calcium, Dietary / Q000008:administration & dosage; D002417:Cattle; D002418:Cattle Diseases / Q000517:prevention & control*; D016009:Chi-Square Distribution; D004343:Drug Implants; D005260:Female; D008297:Male; D010319:Parturient Paresis / Q000517:prevention & control*; D010758:Phosphorus / Q000097:blood; D011247:Pregnancy; D011897:Random Allocation
chemical_list: D002136:Calcium, Dietary; D004343:Drug Implants; D010758:Phosphorus; C048149:24-fluoro-1,25-dihydroxycholecalciferol; D002117:Calcitriol; D002118:Calcium