Periódicos Brasileiros em Medicina Veterinária e Zootecnia

Effects of polyunsaturated fatty acids (PUFA) supplementation on reproductive performance of beef heifers submitted to fixed-time artificial insemination (FTAI) protocol

Borges, João Batista SouzaGonsioroski, Andressa VarellaSilva, Eduardo Pradebon da

Background: More recently, polyunsaturated fatty acids (PUFA) supplements have been used in grazing beef herds inattempt to influence specific metabolic pathways and hormones that directly modulate reproductive function. Supplementation of calcium salts of PUFA can positively influence ovarian follicular growth, luteal function, and improve reproductiveperformance in dairy and beef females. The aim of this experiment was to evaluate strategies of dietary treatments usingPUFA supplementation for 30 days before or after FTAI protocol and its effects on of ovulatory follicle size, ovulation,pregnancy and gestational losses rates in beef heifers.Materials, Methods & Results: One hundred and ninety-nine Brangus heifers (24 ± 3 months-old; BW= 320 ± 15 kg;BCS= 2.85 ± 0.17) were randomly assigned in three different groups to receive dietary treatments. Group 1 (n = 70) wasfed with 0.5 kg/day of a protein-mineral mixture supplement containing 0.2 kg/day PUFA (Mix A) during 30 days before FTAI, Group 2 (n = 68) received the same supplement 30 days after FTAI and Control (n = 61) only the supplementwithout PUFA (Mix B) during all period. Heifers were submitted to estrous synchronization treatment using progesterone(P4), estradiol benzoate (E2) and prostaglandin F2α (PGF). Ultrasound exams were done to measure ovulatory folliclediameter and to determinate ovulation and pregnancy rates on Days 30 and 60 after FTAI. Daily gain (DG) was higher (P< 0.05) only when heifers received supplement containing PUFA (Group 1= 30 days prior FTAI) and (Group 2= 30 daysafter FTAI). PUFA supplementation before FTAI also resulted in larger ovulatory follicles diameter (P < 0.05) in Group1 (11.2 ± 2.5 mm) compared to Group 2 (9.9 ± 2.3 mm) and Control (10.0 ± 2.07 mm). Ovulation rates were similar (P >0.05) in Group 1 (90%), Group 2 (75%) and Control (67%). Pregnancy rates were higher (P < 0.05) in Group 1 (Day 30=67.1% and...(AU)

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