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Physiological response of beef heifers after receiving a reused CIDR processed with different heat-treating methods
Eighty-one prepubertal beef heifers were used to evaluate effects of used CIDR heating methods on concentrations of progesterone after CIDR reinsertion. Used CIDRs were previously in beef cows for 7 d. Heifers were stratified by weight and birth date, then assigned to receive a new CIDR (New, n = 10), or one of eight used CIDR treatments; 1) no processing (Used, n = 10); 2) autoclaved (Autoclaved, n = 8); 3) processed in dishwasher (Dishwasher, n = 8); 4) processed in microwave for 30 s, (Microwave, n = 10); 5) processed in toaster oven (Oven, n = 9); 6) processed in clothes dryer (Dryer, n = 10); 7) processed in boiling water (Boiled, n=8); or 8) stored outdoors for 60 d (Outside, n = 8). Used CIDRs were processed at 121°C for 30 min for autoclaved and oven treatments, at 121°C for boiled treatment, and for 30 minutes for dryer and dishwasher treatments. Blood samples were collected on d -10, immediately prior to CIDR insertion (d 0), 3 h after CIDR insertion (3 h), daily while CIDR was in place (d 1 to 11), and 24 h after CIDR removal (d 12) for analysis of concentrations of progesterone. A treatment × time interaction (P < 0.0001) was present for concentrations of progesterone. No differences (P > 0.10) in concentrations of progesterone were present for heifers receiving a used CIDR compared with heifers receiving CIDRs processed in a dishwasher, microwave, oven, dryer, or boiling water (collectively reported as ‘Processed’). However, heifers receiving autoclaved CIDRs had greater (P < 0.05) concentrations of progesterone from 3 h to d 3, but similar (P > 0.10) concentrations of progesterone from d 4 to d 11 compared with heifers receiving used or processed CIDRs. From d 1 to d 11 heifers receiving outside CIDRs had decreased (P < 0.05) concentrations of progesterone compared with all other treatments. Heifers receiving autoclaved CIDRs had greater (P < 0.05) concentrations of progesterone compared with all other treatments at 3 h and 1 d, whereas heifers receiving new CIDRs had greater (P < 0.05) concentrations of progesterone from d 6 to d 11 compared with all other treatments. Processing used CIDRs with a dishwasher, microwave, oven, clothes dryer, or boiling water did not result in a pattern of concentrations of progesterone similar to that of autoclaved or new CIDRs.
Keywords: Heifers, Progesterone, Reused CIDR