[ comparison of the effect of food sources of saturated and unsaturated fatty acids on ovarian activity of holstein dairy cows in close up period]

Background: Application of different sources of fatty acids and their effect on ovarian performance is a current issue in animal science and research centers

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Objectives: The purpose of this study was to determine the effect of different fatty acids in close-up period on population and size of follicles and measuring blood parameters related to the energy state of the body after calving of lactating dairy cows

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Methods: In this study 15 Holstein cows were selected by expected date of parturition [around 30 days before calving] and assigned them randomly within treatments diets. The diets were formulated to be isonitrogenous. Cows were fed 1] control [carbohydrate source], 2] Rumen-protected fat [RF] [saturated fatty acids] and 3] Roasted Soybean [RS] [unsaturated fatty acids]. Blood sample was collected at 7 day intervals in -21, -14, -7, 1, 7, 14, 21 periods of calving. Also dry matter intake and body condition score cows were recorded. Ovarian activity was monitored by daily transrectal ultrasound scanning from 30 to 40 and 61 to 70 DIM

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Results: Average plasma glucose and cholesterol concentration were significantly different among treatment groups. Numerically, follicular classes were higher in cows, fed with fat diet compared with control group

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Conclusions: According to the results of this experiment, it seems that application of polyunsaturated fatty acids, to improve the energy and ultimately the function of the ovaries, has more advantage than saturated fatty acids