Holstein-Gyr crossbred cattle are strategic for dairy systems in tropical countries, since they combine milk yield genetics with adaptability to tropical climate. However, Holstein (Bos taurus) and Gyr (Bos indicus) breeds present remarkable differences regarding reproductive physiology. Brazil stands out as the world’s largest user of embryo in vitro production (IVP) in bovine, and the use of this technique is increasing in dairy systems. As Holstein-Gyr crossbreds are important oocyte donors for IVP, the present work aimed at investigating whether increased Gyr or Holstein breed composition influences donor’s performance. Sixteen Holstein-Gyr crossbred females presenting increased (HG, 71.4 to 87.5% Holstein; n = 9) or decreased (GH, 40.2 to 46.6% Holstein; n = 7) Holstein composition were submitted to three ovum pick up (OPU) sessions. We observed similar (P = 0.2946) antral follicle count between HG and GH donors (24.8 ± 3.2 vs 29.4 ± 2.8 respectively; mean ± SEM). Groups also display similar morphological oocyte grading (Grade I: 0.1 ± 0.1 vs 0.1 ± 0.1 – P = 0.9680; Grade II: 0.9 ± 0.5 vs 1.9 ± 0.5 – P = 0.1942; Grade III, 4.0 ± 1.2 vs 7.2 ± 1.4 – P = 0.1047, HG vs GH respectively; mean ± SEM). Additionally, the proportion of viable oocyte was similar between HG and GH groups (27.8% vs 31.9%, respectively, P = 0.3500) and oocyte lipid area fraction (6.8% vs 9.5%, respectively; P = 0.1539). Our results indicate that the individual variation has more influence than breed composition of crossbred oocyte donors.
Keywords
Crossbred, Girolando , Oocyte donor, OPU
References
AbeH , YamashitaS , SatohT , HoshiH.2002 . Accumulation of cytoplasmic lipid droplets in bovine embryos and cryotolerance of embryos developed in different culture systems using serum-free or serum-containing media . Mol Reprod Dev , 61 , 57 - 66 .
BaruselliPS , FerreiraRM , SalesJN , GimenesLU , Sá FilhoMF , MartinsCM , RodriguesCA , BóGA.2011 . Timed embryo transfer programs for management of donor and recipient cattle . Theriogenology , 76 , 1583 - 1593 .
BridgesGA , PortilloGE , AraujoJW , ThatcherWW , YelichJV . 2005 . Efficacy of either a single or split treatment of PGF2alpha after a 14 day melengestrol acetate treatment to synchronize estrus and induce luteolysis in Bos indicus x Bos taurus heifers . Theriogenology , 64 , 344 - 362 .
BóGA , BaruselliPS , MartínezMF . 2003 . Pattern and manipulation of follicular development in Bos indicus cattle . Anim Reprod Sci , 78 , 307 - 326 .
ChairGP . 2015 Statistics of Embryo Collection and Transfer in Domestic farm animals : Embryo Technology Newsletter . 34 : 74 p. 2016 .
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