Abstract
Our objectives were to characterize the incidence of vaginitis caused by a controlled internal drug release (CIDR) device and its effects on fertility of beef females enrolled on estrus synchronization followed by timed-artificial insemination (TAI). A total of 1,097 mature cows and 215 heifers from 9 different locations were enrolled in the 7-d CO-Synch + CIDR synchronization protocol. At CIDR insertion, all females were inspected for any previous signs of vaginitis prior to enrollment in the experiment. As evidence of vaginitis, a CIDR score was determined at CIDR removal, and an AI plastic sheath score was also performed at TAI following a 1 to 4 system: 1=clean presenting no secretion; 2=clean presenting clear secretion; 3=presence of purulent secretion; 4=presence of purulent secretion and blood. Pregnancy status was determined by rectal ultrasonography approximately 40 days after TAI. The scores for CIDR and AI plastic sheath did not differ between cows and heifers. Of all females, 6% had a CIDR score of 1, 31% score 2, 56% score 3, and 7% score 4. Plastic sheath score was 1 for 16%, 2 for 62%, 3 for 15%, and 4 for 7% of females. Pregnancy rate to TAI differed between cows and heifers (P < 0.01), among locations (P < 0.001) and ranged from 36 to 66%; however, it was not influenced by CIDR score (P = 0.259) and plastic sheath score (P = 0.785). Pregnancy rate of females by different CIDR scores was 60%, 57%, 52%, and 46% for scores 1, 2, 3, and 4, respectively. Pregnancy rate of females by different AI plastic sheath score was 60%, 55%, 45%, and 48%, for scores 1, 2, 3, and 4, respectively. The presence of vaginitis caused by a CIDR does not influence pregnancy rates of TAI in beef females.
Hormonal manipulations in the 5-day timed artificial insemination protocol to optimize estrous cycle synchrony and fertility in dairy heifers
