Comparison of different sources of fatty acids in close up period on ovarian cycle activity and blood parameters of primiparous Holstein dairy cows

The effect of different fatty acids in close–up period on population and size of follicles and blood parameters related to the energy state of the body after calving of lactating dairy cows was measured. In this study 12 Holstein cows were selected by expected date of parturition (around 30 days before calving) and assigned them randomly within one of the three experimental treatments including: 1) control (with carbohydrate source)، 2) Rumen-protected fat (RF) and 3) Roasted Soybean (RS). The diets were formulated to be isonitrogenous and not iso-caloric. Blood samples were 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 60 to 70 DIM. In blood parameters section only glucose concentrate، significantly was different among treatment groups and the value of glucose in RS group was higher than RF group. Reproductive activity in cows that were fed RS group was higher than RF group. Differences in dry matter intake and body condition score were not significant.