Avaliação econômica da produção in vitro de embriões bovinos de diferentes grupos genéticos em sistema comercial

Abstract

The in vitro production (IVP) bovine embryos is a biotech that, associated with use of sexed semen, allows the multiplication of females of high genetic value. The general goal at this thesis was to analysis commercial data of in vitro embryo production from a private biotech company, discussing economic information of this biotechnology. The first experiment aimed to evaluate, during three years, the number and developmental competence of oocytes recovered from different genetic groups of the donors (Bos taurus indicus and Bos taurus taurus), and the ability of sexed or conventional semen to produce in vitro (IVP) bovine embryos, under the influence of season (dry and water). The data were collected from a commercial company specialized in ovum pick-up and in vitro production embryos (OPU-IVP). The total number of collected oocytes, the rates of viable and cleaved oocytes and IVP bovine embryos were analyzed in linear regression models. Zebu donors, although with differences between breeds, produced a greater (P<0.001) number of oocytes per OPU session and higher rates (P<0.001) of viable and cleaved oocytes and IVP embryos in relation of Bos taurus taurus donors. However, Holstein donors produced a greater (P<0.001) number of oocytes per OPU session and higher rates (P<0.001) of viable and cleaved oocytes in relation of Gyr donors, while showed a lowerproduction of embryos. The conventional semen had higher rates of IVP embryos (P<0.001) in relation of sexed semen. In order to evaluate the influence of season (dry and wet period), there was no direct effect in the results of Bos taurus taurus and Bos taurus indicus females for any ofthe variables studied (P>0.2). Then, in order to evaluate operational costs and some economic indicators of IVP system from a commercial laboratory of IVP bovine embryos, data of Bos taurus indicus and Bos taurus taurus donors were collected. Variable operational costs accounted for 90.78% of the entire cost of IVP embryo in the lab, where the highest costs were the medias used in the process of maturation, fertilization and embryo culture (55.34%), and laboratory labor (27.76%). The best convertin rate of in vitro culture zygotes to embryos, obtained in Zebu donors regarding Bos taurus taurus donors, represented an average profit per embryo of R$34.18 against R$19.34, respectively. The IVP lab activity had a higher accumulated revenue (R$2,572,430.00) in relation of operational costs (R$1,351,287.65), determining operational profit and a great economic capacity of the laboratory to grow. In the third experiment, conducted in a breeding season from a commercial beef cattle farm, aimed to analyse, technically and economically, the large-scale production of male calves derived from IVP embryos fertilized with sexed semen and using the fixed-time embryo transfer (FTET)technique. 974 Nelore and cross-breeding females were synchronized, achieving an utilization rate of 84.4%. In order to reduce the cost of IVP embryos, OPU technique was replaced by collecting ovaries of slaughtered Nelore cows. A total of 3054 oocytes were collected from 500 ovaries, resulting in production of 1050 embryos fertilized with male Angus sexed semen. 822 embryos were transferred, achieving 345 pregnancies (42%), with 328 (95.1%) males and 17 (4.9%) females. A simulation with data from the farm itself, using fixed-time aritificial insemination (FTAI) with sexed semen, was used for a comparative study. 30% pregnancy rate was obtained in the FTAI, resulting in 278 males and 15 females. The FTET project, after the sale of weaned calves, will have a gross margin of R$135,382.00 against R$132,855.00 from FTAI simulation with sexed semen. The proposed methodology of ovum pick-up of ovaries from slaughtered cows to realize a project of large-scale male embryos, reducing the cost of IVP, represent a new market alternative in beef cattle systems.