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Submitted to: Meeting Proceedings
Publication Type: Proceedings Publication Acceptance Date: 1/6/2008 Publication Date: 3/20/2008 Citation: Geary, T.W. 2008. Tips to Improve AI Pregnancy Rates. Proceedings XII Course on New Approaches to Production and Reproduction in Cattle, March 6-7, 2008, Uberlandia, Brazil (Portuguese only - CD only) pg 80-92. Interpretive Summary: This is a review paper that is aimed at identifying and emphasizing the critical factors that contribute to a successful AI breeding season. Those factors are: 1. Percentage of cows detected in estrus and inseminated, 2. Inseminator efficiency, 3. Fertility level of the cow herd, and 4. Semen fertility. Accurate and efficient heat detection is the first step toward achieving AI pregnancies. Use of heat detection aids, hours spent observing estrus and manipulation of treatments so that the majority of cows will exhibit estrus during daylight hours will improve our success. Inseminator efficiency is dependent on ability and accuracy of correctly depositing semen in the uterine body. Some of the factors affecting cowherd fertility include proper nutrition, good health, adequate time postpartum in cows and age/weight of heifers as well as management of females after AI. Semen fertility differences between bulls and within bulls are discussed. Technical Abstract: This paper is aimed at identifying and emphasizing the critical factors that contribute to a successful AI breeding season. Accurate and efficient heat detection is the first step toward achieving AI pregnancies. Electronic estrous detection is not necessary if producers will spend more time observing females for estrous behavior. Estrous synchronization improves our ability to detect cows and heifers in heat because it concentrates and increases the intensity and duration of their estrous behavior. Timing of synchronization should be manipulated so that the majority of cows exhibit estrus during daylight hours. Various heat detection aids can be helpful in improving our heat detection efficiency, but they need to be used in conjunction with visual observation of cows. Sorting cows into a separate pen as soon as they are identified in estrus allows other cows to express estrous behavior and increases the amount of attention producers can focus on these new cows. The effects of timing of AI on pregnancy rate are discussed. Factors that increase size of the ovulatory follicle should increase AI pregnancy rates. Clitoral stimulation should be used by AI technicians after insemination of cows, but not heifers. Transportation stress that is necessary for cows or heifers that are artificially inseminated should occur within the first 4 days following AI to prevent embryonic mortality. Semen fertility differences exist between bulls and within some bulls collected on different dates. Producers are encouraged to learn as much information about the fertility of semen used for AI breeding seasons. |
