Effect of synchronization of follicle-wave emergence with estradiol and progesterone and superstimulation with follicle-stimulating hormone on milk estrogen concentrations in dairy cattle |
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| Authors: | Lucilene B de Souza Raynald Dupras Louis Mills Younès Chorfi Christopher A Price |
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| Institution: | Centre de recherche en reproduction animale, Faculté de médecine vétérinaire, Université de Montréal, 3200, rue Sicotte, Saint-Hyacinthe, Québec J2S 7C6 (de Souza, Chorfi, Price); Medi-Vet Inc, 167, rue Notre-Dame, Notre-Dame-du-Bon-Conseil, Québec J0C 1A0 (Dupras, Mills). |
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| Abstract: | Very little is known about the effects of hormonal synchronization of follicle waves and superovulation on the estrogen content of a cow’s milk. The objective of this study was to determine the effect in dairy cows of synchronization with estradiol-17β (E2) and progesterone (P4) on milk E2 concentrations and to compare these levels with those achieved during superstimulation for 4 d with porcine follicle-stimulating hormone (FSH). The milk E2 concentrations were raised significantly above pretreatment levels (P < 0.05) for 2 d after synchronization, the mean peak being 40.2 ± 18.5 (standard error) pg/mL and the pretreatment mean 1.5 ± 0.5 pg/mL. The mean peak E2 concentration during ovarian stimulation was 4.4 ± 0.7 pg/mL. The mean E2 concentration was significantly higher (P < 0.05) after synchronization than during superstimulation for the 1st milking after synchronization but not subsequent milkings. The milk estrone concentrations were above pretreatment levels for 1 d after synchronization and were not different from those observed during superstimulation. |
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