Time of insemination relative to reaching activity threshold is associated with pregnancy risk when using sex-sorted semen for lactating Jersey cows
| Autor: | Ricardo C. Chebel, Gabriel D. Bombardelli, Henrique F. Soares |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
0301 basic medicine
Male Ovulation medicine.medical_specialty Time Factors Pregnancy Rate media_common.quotation_subject medicine.medical_treatment Semen Insemination 03 medical and health sciences Animal science Food Animals Estrus Pregnancy medicine Animals Lactation Sex Preselection Small Animals Insemination Artificial media_common Probability Gynecology Estrous cycle Equine business.industry Artificial insemination 0402 animal and dairy science Pregnancy Outcome 04 agricultural and veterinary sciences medicine.disease 040201 dairy & animal science Spermatozoa Pregnancy rate 030104 developmental biology Herd Animal Science and Zoology Cattle Female business |
| Zdroj: | Theriogenology. 85(3) |
| ISSN: | 1879-3231 |
| Popis: | The objective of this observational experiment was to determine the association between the interval from reaching activity threshold (AT) to artificial insemination (AI) with sex-sorted semen and the probability of pregnancy. Jersey cows (n = 678) from a commercial dairy herd were fitted with heat-rumination long-distance collars (SCR Ltd., Netanya, Israel) at approximately 42 ± 7 days postpartum. Cows were presynchronized with three injections of PGF2α given 14 days apart starting on Day 39 ± 3 postpartum. Cows in estrus, based on tail paint removal, after 50 ± 3 days postpartum were inseminated by one of three technicians with semen from one of six sires. Cows were examined for pregnancy at 31 ± 3 and 66 ± 3 days after insemination. Only cows inseminated in estrus and examined for pregnancy at 31 ± 3 days after AI were used in the experiment (n = 419). A subsample of cows (n = 35) were examined by ultrasound every 8 hours after reaching AT to estimate the interval from reaching AT and ovulation. The mean (± standard error of the mean) interval from reaching AT to AI was 16.9 ± 0.5 hours, whereas the interval from peak activity to AI was 9.8 ± 0.5 hours. The length of high activity among cows diagnosed in estrus was 17.3 ± 0.3 hours. The mean interval from reaching AT to ovulation was 25.7 ± 1.2 hours. There was a quadratic effect of the interval between reaching AT and AI on probabilities of pregnancy at 31 ± 3 (P = 0.07) and 66 ± 3 (P = 0.15) days after AI. Pregnancy per AI at 66 ± 3 days after AI was higher for cows inseminated between 23 and 41 hours after the onset of estrus (≤ 3 hours = 20.0%, 4-12 hours = 27.1%, 13-22 hours = 39.1%, 23-41 hours = 45.6%, and ≥ 42 = 40.0%). Insemination of lactating Jersey cows with sex-sorted semen closer to expected ovulation yielded the highest probability of pregnancy. |
| Databáze: | OpenAIRE |
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