Progesterone concentrations in milk fat at first insemination — effects on non-return and repeat-breeding
| Autor: | K. Landsverk, Elisabeth Kommisrud, Erik Ropstad, A. Waldmann, A. O. Refsdal, Ellen Dahl, Olav Reksen |
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| Rok vydání: | 2001 |
| Předmět: |
Male
medicine.medical_specialty medicine.medical_treatment media_common.quotation_subject Fertility Biology Insemination Fats Immunoenzyme Techniques Endocrinology Animal science Food Animals Pregnancy Internal medicine medicine Animals Least-Squares Analysis Insemination Artificial Progesterone media_common Reproduction Artificial insemination Antibodies Monoclonal General Medicine Odds ratio Cattle dairy Milk Milk fat Herd Cattle Female Animal Science and Zoology Norwegian Red |
| Zdroj: | Animal Reproduction Science. 65:33-41 |
| ISSN: | 0378-4320 |
| DOI: | 10.1016/s0378-4320(00)00227-x |
| Popis: | The relationship between milk fat progesterone concentration at first artificial insemination (AI) and reproductive performance of Norwegian Red Cattle dairy cows was investigated in a field study. Fifteen AI technicians collected milk samples from 2250 cows from 458 herds and progesterone was analysed in the milk fat portion of the samples. Logistic regression revealed decreased probability of non-return, and increased likelihood of repeat-breeding, with increasing progesterone concentrations at insemination. The odds ratio for non-return and for repeat-breeding between the minimum and maximum value for milk fat concentrations between 4 and 32.2ng/ml was 4.5 (P0.01) and 3.2 (P = 0.01), respectively. The variable 'Technician' did not significantly influence non-return rate or repeat-breeding. Progesterone concentration at AI was positively related to calving to last insemination interval, and to number of inseminations per cow (P0.05). The association between the progesterone concentration at insemination and calving interval was only marginally significant. Technician was significantly (P0.01) associated with interval from calving to first AI, interval from calving to last AI (P = 0.05), and number of AI per cow (P = 0.01). Technician was not significantly related to the calving interval. We conclude that increased suprabasal progesterone concentrations at the time of first insemination, and higher return rate at AI may, at least partly, be due to endocrinological asynchrony at AI, a condition which may lead to decreased fertility. |
| Databáze: | OpenAIRE |
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