Bowers, C. L.

Brown, C. G.

Gandy, S.

Neuendorff, Don A.

Randel, R. D.

Willard, S. T.

English

Texas A&M University

Observational Versus Electronic Methods for the Detection of Estrus in Farmed Red Deer Hinds

Texas A&amp;M Repository

    PUBLICATIONS 2002 OBSERVATIONAL VERSUS ELECTRONIC METHODS FOR THE DETECTION OFESTRUS IN FARMED RED DEER HINDSS. D. Bowers, C. G. Brown, T. A. Strauch, S. Gandy, D. A. Neuendorff,R. D. Randel and S. T. WillardBackground. Artificial insemination has been widely used in farmed deer, howeverconception rates following AI remain variable. This variability in conception rates may be due toAI technique, species-specific responses to estrous synchronization protocols, and variations inthe optimal timing for insemination. The ability to monitor estrus behavior, including durationand intensity of estrus, could increase AI conception rates in cervids and thus decrease variabilityby increasing the precision in which estrus and ovulation can be predicted. The HeatWatch™(HW; DDX, Inc., Denver, CO) electronic estrus detection system has the ability to detect estrusand record the time and duration of individual mounts. The HW system has been usedsuccessfully in cattle, and could be a significant resource for deer farmers if the system canaccurately detect estrus in red deer. Therefore, the objectives of this study were to examine theefficacy of the HeatWatch electronic estrus detection system for monitoring behavioral estrus inred deer hinds and, to determine whether estrous synchronization alters duration or intensity ofestrus behavior and AI conception rates in red deer hinds.Research Findings. The range from CIDR withdrawal to estrus was 29 to 91 hours, witha mean interval of 47.5 ± 3.3 hours (Table I). There was no difference (P>.IO) in time fromCIDR removal to estrus between the yearling IE (43.17 ± 3.12 hr) and the mature IE hinds (49 ±4.32 hr). Within 25 days on trial (the time in which hinds were housed with the three sterilestags), 41 hinds (82 %) were observed in estrus and bred by AI. The use of a CIDR followed byan injection of PMSG resulted in more red deer hinds detected in estrus; 96 % of IE hinds wereobserved in estrus and bred by AI (P<.05) compared to 68% of NE hinds. Although notsignificant (P>.IO), the IE hinds had a higher pregnancy rate (41.6 %) than the NE hinds (29.4%). However, in both treatment groups the yearling hinds had higher pregnancy rates (100 %;P<.05) than the mature hinds (IE: 22.2 %; NE: 14.3 %). There was a 46.7 % first servicepregnancy rate among the hinds that returned to estrus in the presence of the clean-up stag, withno difference (P>.IO) noted between the IE and NE treatment groups. The overall herdpregnancy rate (AI and clean-up stag) was 58%.When the hinds were housed with the three young sterile stags all of the hinds that werebred by AI (n=41) were detected in estrus by visual appraisal of stag marks, while only 13 (3 1.7%; P<.OO I) of those hinds observed were detected by HW (Table 2). However, when the hindswere housed with the mature clean-up stag 93.3 % of the hinds detected in estrus by visual101appraisal were also detected by HW. This suggests the success of HW in estrus detection may beaffected by age (size) of the stag used for breeding. In both situations the top transmitter recordedmore events (89.8 %; P<.OOI) than the bottom transmitter (10.2 %). There were no differences(P>.10) in number and duration of mounts with respect to treatment groups. However, there weredifferences (P<.05) in number and duration of mounts in relation to which stag they were housedwith. When the hinds were housed with the three young stags, a lower number of mounts (1.83 ±.59) was recorded then when hinds were housed with the clean-up stag (4.54 ± .78). However,the duration of each mount was longer when the hinds were housed with the young stags (2.36 ±.56 sec) compared to the clean-up stag (1.46 ± .08 sec); although this difference in duration wasunder one second.Table 1. Estrous Synchronization, artificial insemination and pregnancy rates for induced estrus(IE; CIDR + PMSG) and natural estrus (NE) red deer hinds.Parameter IE Hinds NE HindsHours from CIDR removal to observed estrus 47.5 ± 3.3 --Percentage of hinds breds by AI 96%4 68%0(24/25) (17/25)Pregnancy rate-AI 41.6% 29.4%(10/24) (5/17)Pregnancy rate-clean up stage 50% 43.8%(7/14) (7/16)Superscnpts differ wlthm IE and NE groups; ab = P<.05.Table 2. HeatWatch and mounting behavior for red deer hinds housed with three young stags orwith a mature clean-up stag.Young Sterile Stags Mature Clean-up StagHinds detected by HW 31.7 %a 98 %b(13/41) (28/30)Top Patch (events)17 124Bottom Patch (events)5 IINumber of Mounts1.83 ± .59a 4.54 ± .78bDuration of Mounts (sec) 2.36 ± .56a 1.46 ± .08bSuperscnpts differ wlthm row: ab-P<.OSApplication. The use of a CIDR followed by an injection of PMSG (IE hinds)resulted in more red deer hinds to be detected in estrus. In addition, the IE hinds had ahigher pregnancy rate than the NE hinds. These data suggest that the success of HW inestrus detection may be affected by age (size) of the stag used. In both situations thehigher placement of the HW patch was more effective than the lower placement.102

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Observational Versus Electronic Methods for the Detection of Estrus in Farmed Red Deer Hinds

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Observational Versus Electronic Methods for the Detection of Estrus in Farmed Red Deer Hinds

Abstract

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Full text

Available Versions

Texas A&M University

Texas A&amp;M Repository

Texas A&M Repository