Factors Affecting Pregnancy Rate to Fixed-Time Artificial Insemination in Pen-Raised White-tailed Deer
Cordova, Jacqueline P.
MetadataShow full item record
White-tailed deer farming has experienced significant growth in recent years in the U.S. with the majority of the operations located in Texas. Producers now utilize advanced breeding technologies in deer similar to cattle and other livestock to enhance the genetic merit of their herd. The goal is to produce the best quality bucks to sell as stocker bucks for high priced hunts or breeding. Pen-raised white-tailed does (n=177; 1 to 6 yr; 28.5 to 72.5 kg) from an established breeding program (3-S Whitetails, Bedias, TX) were utilized to evaluate factors affecting pregnancy rate to fixed-time AI (FTAI) across four breeding seasons combined (2013-2016). Does were synchronized using a 14-d controlled internal drug release (CIDR; EAZI-Breed CIDR, Zoetis, Inc., Kalamazoo, MI) device as a progesterone source with an injection (i.m.) of eCG (200 IU) at CIDR removal and inseminated laparoscopically 60 h later. At the time of FTAI, BW, BCS, and disposition score (DISP) were recorded and a blood sample was collected via jugular venipuncture to determine serum cortisol concentration. All does were subsequently placed in a pen with a buck for natural service (NAT) to maximize overall pregnancy rate of the herd. DNA testing of each fawn determined parentage and birth dates based on records from the producer were used to determine method of conception (FTAI or NAT). Serum cortisol concentrations were determined via ELISA. Data were analyzed using the GLM, MIXED, LOGISTIC and CORR procedures of SAS. There were no significant differences (P>0.05) found in BW, age, BCS, DISP, or serum cortisol concentration between does that conceived to FTAI and those that did not. Pregnancy rate to FTAI was 61% and overall pregnancy rate (FTAI and NAT) was 86%. Mean litter size was greater (P<0.02) for FTAI (1.79) than NAT (1.48). Does that did not conceive to FTAI had lower (P<0.05) BW, BCS and were younger (P<0.05) than does that conceived to FTAI. In summary, additional research is needed to determine if any of the physiological factors measured in this study have a significant influence on conception rate to FTAI.