Hormona Antimülleriana como predictor del recuento de folículos antrales en vacas Holstein mestizas bajo sistema de pastoreo sobre los 2.500 msnm

Abstract

The present research was performed on 135 crossbred Holstein cows. The objectives were: 1) to characterize the levels of Antimülleriana hormone (AMH), to classify cows with high and low levels of this glycoprotein, and 2) to determine if the groups with high and low levels of AMH are related to the number of antral follicles (NFA). The follicular wave was synchronized with a conventional fixed-time artificial insemination (FTAI) protocol: day 0 = intravaginal device CIDR + 2mg of estradiol benzoate (IM). Day 7 = removal of CIDR plus 25 mg of prostaglandin and then application of heat detection patches; Day 8 = 1mg estradiol benzoate; Day 9 (54h post-implant removal) = transrectal ultrasonography evaluation to determine the location of the preovulatory follicle; and Day 11= 4ml of blood was taken from the coccygeal vein in tubes with EDTA, then it was centrifuged at 3,000rpm / 20min, the plasma was recovered and frozen at -20 ° C, until AMH analysis using the sandwich ELISA kit (DL-AMH-b kit, Develop®, China). The RFA was performed at day 11, using a portable ultrasound machine (Aloka ProSound 2®, Tokyo- Japan), with a linear probe and 7,5 MHz A plasma AMH concentration of 0,06 ± 0,03 ng / ml was established, with a range between 0,03 and 0,16 ng / ml and an RFA ≥ 3mm of 17,26 ± 0,38 follicles, with values between 30 and 7 follicles. A correlation and association between AMH and RFA high and significant (r = 0,783; p <0,0001 and R2 = 0,613 respectively). When performing groups of high, medium and low AMH concentration, there are on average three times more AMH (0,14 ± 0,02 ng / ml) in the high group, in relation to the low group (0,04 ± 0,001 ng / ml; p <0,05). In effect, the concentration of AMH is directly related and associated with RFA.