Abstract #841
Section: Production, Management and the Environment
Session: Production, Management, and the Environment VI
Format: Oral
Day/Time: Thursday 9:00 AM–9:15 AM
Location: Panzacola F-4
Session: Production, Management, and the Environment VI
Format: Oral
Day/Time: Thursday 9:00 AM–9:15 AM
Location: Panzacola F-4
# 841
Reproductive outcomes following presynchronization of dairy heifers with a 14-d CIDR and prostaglandin F2α.
Courtney K. Claypool*1, Jennifer A. Spencer1, Saulo Menegatti Zoca3, Bahman Shafii1, William J. Price1, Amin Ahmadzadeh1, Neil R. Rimbey2, Joseph C. Dalton2, 1University of Idaho, Moscow, ID, 2University of Idaho, Caldwell, ID, 3UNESP, Botucatu, Sao Paulo, Brazil.
Key Words: dairy heifer, presynchronization, CIDR
Reproductive outcomes following presynchronization of dairy heifers with a 14-d CIDR and prostaglandin F2α.
Courtney K. Claypool*1, Jennifer A. Spencer1, Saulo Menegatti Zoca3, Bahman Shafii1, William J. Price1, Amin Ahmadzadeh1, Neil R. Rimbey2, Joseph C. Dalton2, 1University of Idaho, Moscow, ID, 2University of Idaho, Caldwell, ID, 3UNESP, Botucatu, Sao Paulo, Brazil.
Efficient pregnancy production in heifers provides an earlier return on investment for dairy producers. The research hypotheses were that presynchronization would result in a faster insemination rate following entry to the breeding program, and an increased proportion of pregnant heifers within the first week of entry into the breeding program compared with no presynchronization. Heifers were assigned to 1 of 3 groups: (1) 14-d CIDR, (2) prostaglandin F2α (2× PG), or control (1× PG). The 14-d CIDR group (n = 119) received a CIDR on d −30, which was removed on d −16. The 14-d CIDR group received an injection of PG (25 mg i.m.) upon entry to the breeding program (d 0). The 2× PG group (n = 118) received an initial injection of PG on d −11, and a second injection of PG on d 0. The 1× PG group (n = 121) received an injection of PG on d 0. Data were analyzed using ANOVA procedures within the generalized linear mixed models in SAS (9.4). All animals received tail paint and were observed for behavioral estrus daily. Pre-synchronization affected (P < 0.05) the proportion of heifers observed in estrus and inseminated in the first week: 95.8% (14-d CIDR), 74.5% (2× PG), 66.9% (1X PG). Days to AI (LSM ± SEM) following entry to the breeding program were also affected (P < 0.05) by treatment: 3.6 ± 0.4 d (14-d CIDR), 4.9 ± 0.4 d (2× PG), 6.8 ± 0.5 d (1× PG). Proportion of heifers pregnant in the first week of the breeding program also differed (P < 0.05): 68% (14-d CIDR), 43% (2× PG), 41% (1× PG). Conception rates to AI in the first week were 71.9% (14-d CIDR), 57.9% (2× PG), and 61.7% (1× PG), and were different (P < 0.05) between 14-d CIDR and 2× PG heifers. Days on feed from entrance to the breeding program to projected calving date were calculated for all heifers: 295 ± 2.6 d (14-d CIDR), 302 ± 2.6 d (2× PG), and 305 ± 2.5 d (1× PG), and were different (P < 0.05) between 14-d CIDR and 1× PG heifers. Pre-synchronization with a 14-d CIDR and PG appears to be an effective strategy to increase the proportion of heifers identified in estrus, inseminated, and pregnant within the first week upon entry to the breeding pen.
Key Words: dairy heifer, presynchronization, CIDR
