Acta Vet. Brno 2010, 79: 525-532

The Effect of Soybean-Derived Phytoestrogens on Concentrations of Plasma Isoflavones, 15-keto-13,14-dihydroprostaglandin F and Progesterone in Dairy Cows

Jarmila Watzková1, Ludmila Křížová1, Aleš Pavlík2, Věra Schulzová3, Jana Hajšlová3, Jaromír Lojza3

1Agriresearch Rapotin Ltd., Department of Animal Nutrition and Quality of Livestock Products, Czech Republic
2Mendel University of Agriculture and Forestry Brno, Department of Animal Morphology Physiology and Genetics, Czech Republic
3Institute of Chemical Technology, Department of Food Chemistry and Analysis, Prague, Czech Republic

The objective of the study was to determine the effect of soybean-derived phytoestrogens and their metabolites on the activity of sex hormones during the oestrous cycle in multiparous lactating dairy cows. The experiment was carried out on 4 multiparous lactating Holstein cows in the form of replicated Latin square in double reversal design. The experiment in the total length of 168 days was divided into 4 periods of 42 days, each consisting of a 21-day preliminary period and a 21-day collecting period. Cows were divided into 2 groups of 2 cows. The control group (C) was fed a diet based on extruded rapeseed cake while the experimental group (S) was fed a diet containing extruded full-fat soya. The intake of total isoflavones was 3297 mg/d in S and 58.0 mg/d in C (P < 0.001). The concentrations of individual isoflavones, it is daidzein, genistein and equol in plasma were significantly higher in the experimental group S (49.3, 78.7 and 218.8 ng/ml, respectively) than in the control group C (13.5, 42.9 and 18.3 ng/ml, respectively, P < 0.001). Plasma concentration of progesterone throughout the oestrous cycle was not influenced by the diet used (P > 0.05). Plasma concentration of prostaglandine PGFM throughout the oestrous cycle in the experimental group (S) tended to be higher (P = 0.095) than in the control group (C). No differences in the length of the oestrous cycle between the cows fed different diets were observed.


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