Dissolution Rates of Calcium Boluses and Their Effects on Serum Calcium in Dairy Cattle.

Autor:	Verhoef W; Bureau Vétérinaire de Richmond, Richmond, Quebec, Canada., Zuidhof S; Sjoert Zuidhof Consulting, Okotoks, Alberta, Canada., Ralston B; Alberta Agriculture and Forestry, Airdrie, Alberta, Canada., Ross JA; Chinook Contract Research Inc., Airdrie, Alberta, Canada., Olson M; Alberta Veterinary Laboratories, Calgary, Alberta, Canada.
Jazyk:	angličtina
Zdroj:	Veterinary medicine (Auckland, N.Z.) [Vet Med (Auckl)] 2021 Feb 03; Vol. 12, pp. 23-32. Date of Electronic Publication: 2021 Feb 03 (Print Publication: 2021).
DOI:	10.2147/VMRR.S293128
Abstrakt:	Purpose: Calcium supplement boluses vary greatly in content and bioavailability. Methods: In vivo dissolution and bioavailability studies were conducted to compare commercial calcium supplement boluses with various contents of calcium chloride and calcium carbonate. The products studied included: Bolus 1 (high calcium chloride, no calcium carbonate), Bolus 2 (medium calcium chloride, medium calcium carbonate), and Bolus 3 (low calcium chloride, high calcium carbonate). A bolus was placed in a pre-weighed coarse mesh net for 30, 60, 90, 120, 180, and 240 minutes to measure dissolution rates in the rumen of fistulated animals. To measure calcium uptake, 27 Holstein cows (second and third lactation) were randomly allocated to one of three oral calcium protocols: Treatment 1 (two high calcium chloride boluses at time 0); Treatment 2 (one high calcium chloride bolus at time 0 with a second bolus 12 hours later); or Treatment 3 (two high calcium carbonate boluses at time 0). Treatments were initiated within 12 hours following calving and this was considered time 0. Results: Bolus 1 was the quickest to dissolve (<90 minutes), followed by Bolus 2 (<240 minutes). The high calcium carbonate bolus (Bolus 3) remained after 240 minutes in vivo with a minimum of 75% of the original bolus weight still intact. Cows with severe hypocalcemia (<1.8 mmol/L) responded with a higher serum calcium increase than cows with milder hypocalcemia (>1.8 mmol/L, <2.12 mmol/L). The high calcium carbonate bolus group (Treatment 3) did not show a rapid increase in serum calcium as compared to the high calcium chloride groups (Treatments 1 and 2). The animals receiving Treatment 1 had a greater and more persistent serum calcium response than animals receiving Treatment 2. Conclusion: The study outcome suggests that calcium chloride/calcium sulfate boluses are more effective at generating a serum calcium response than boluses containing high amounts of calcium carbonate and that two boluses administered rapidly after calving may be more effective than the traditional treatment of giving 2 boluses 12 hours apart. Competing Interests: Dr Walter Verhoef reports personal fees from Solvet Canada, during the conduct of the study; personal fees from Bureau Vétérinaire de Richmond and Solvet Canada, outside the submitted work; is a partner in Bureau Vétérinaire de Richmond, and was consulting for Solvet. Dr Brenda Ralston reports Dr Merle Olson was her Masters supervisor in 2001; they have published numerous other papers and have collaborated on various grants. Dr Joseph A Ross reports compensation paid to his employer (Chinook Contract Research) for time spent writing, preparing figures, and statistical analyses for Alberta Veterinary Laboratories, during the conduct of the study. Dr Merle Olson reports personal fees from Alberta Veterinary Laboratories, during the conduct of the study; receives salary from Solvet, and Sjoert Zuidhof is providing consulting services to Solvet, which markets the Cal-Boost bolus. The authors report no other potential conflicts of interest for this work. (© 2021 Verhoef et al.)
Databáze:	MEDLINE
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