132 Effect of treatment with follicle-stimulating hormone on in vitro embryo production of Gyr (Bos indicus) calves, pubertal heifers and adult cows
Authors: Elliff F. M. , Guimarães E. C. , Féres L. F. , Bayeux B. M. , Colli M. H. A. , Sampaio Baruselli P. S. 
Published: December 2018

The aim of this study was to evaluate the effect of FSH treatment on the in vitro embryo production of Gyr (Bos indicus) calves (3-10 months), pubertal heifers (16-21 months) and adult cows. Thirty females were used: 10 calves, 10 pubertal heifers (puberty was determined by the presence of a corpus luteum) and 10 cows. The animals were distributed as follows: calves: control (C-C, n=5) and with FSH (FSH-C, n=5); heifers: control (C-H, n=5) and with FSH (FSH-H, n=5); and adult animals: control (C-A; n=5) and with FSH (FSH-A; n=5). All animals received an intravaginal progesterone device (calves-Primer PR®, Agener União, Brazil; heifers and cows-Prociclar®, Ceva Saúde Animal, Brazil) and oestradiol benzoate (calves and heifers: 1mg, cows: 2 mg; Fertilcare Sincronização®, MSD Saúde Animal, Brazil) on Day 0. The control animals of each category received no additional treatment. The FSH-C received 80mg IM of FSH (Folltropin®, Vetoquinol, Mairipora, Brazil), performed in 4 injections twice a day in decreasing doses [25mg (Day 4, p.m.), 25mg (Day 5, a.m.), 15mg (Day 5, p.m.), and 15mg (Day 6, a.m.); coasting period: 24 h]. The FSH-H received 100mg IM of FSH, performed in 4 injections twice a day in decreasing doses [30mg (Day 4, p.m.), 30mg (Day 5, a.m.), 20mg (Day 5, p.m.), and 20mg (Day 6, a.m.); coasting period: 24 h]. The FSH-A received 140mg IM of FSH, performed in 4 injections twice a day in decreasing doses [40mg (Day 4, a.m.), 40mg (Day 4, p.m.), 30mg (Day 5, a.m.), and 30mg (Day 5, p.m.); coasting period: 48 h]. On Day 7 the intravaginal devices were removed and all animals were submitted to epidural anaesthesia (2% lidocaine) followed by ovum pickup guided by transvaginal ultrasound (guide EC9-5 Heifer, WTA, Sao Paulo, Brazil; ultrasound S8®, SonoScape, Shenzhen, China). The recovered oocytes were sent to a commercial laboratory for the in vitro embryo production. The obtained data were analysed by the GLIMIX procedure of SAS® (SAS Institute Inc., Cary, NC, USA; means are presented as standard error of the mean. The oocyte recovery rate was lower (P=0.01) for calves and heifers treated with FSH (FSH-C: 42.8%; FSH-H: 55.2%) when compared with control calves and heifers (C-C: 65.1%; C-H: 81.1%); however, no difference was observed for cows (C-A: 63.7%; FSH-A: 63.1%). The number of viable oocytes differed according to the category (P=0.001); calves and cows had higher numbers of viable oocytes (calves: 11.6±0.7; cows: 11.7±0.9) when compared with heifers (23.4±0.6). The number of cleaved oocytes increased (P=0.03) when calves (FSH-C: 8.0; C-C: 5.8) and cows (FSH-A: 8.8, C-A: 6.0) were treated with FSH. Cleavage rate was higher (P=0.05) when animals of all categories were treated with FSH (calves=52.7%; heifers=68.0%; cows=67.9%), when compared with nontreated animals (45.8%; 60.1%; 51.8%, respectively). The number of blastocysts per ovum pickup increased (P=0.04) when calves (FSH-C: 3.2; C-C: 1.5) and cows (FSH-A: 5.8; C-A: 2.8) were treated with FSH. The number of vitrified embryos (percentage of blastocysts surviving vitrification) increased (P=0.02) when calves (FSH-C: 2.6; C-C: 1.0) and cows (FSH-A: 5.0; C-A: 2.4) were treated with FSH. These results show that treatment with FSH increases the efficacy of in vitro embryo production in Gyr calves and cows.