Folliculogenesis, Fertility and Biotechnology in Dairy Cattle

The ovarian follicle population is formed by thousands of follicles, preantral and antral, where oocytes are included. During fetal life, the first follicles produced are preantral, and, as they undergo the development process, they reach the final stage of antral follicles, where a cavity/or antrum is developed. All this growth phase is called folliculogenesis, and this chapter will abord the most important aspects of this process. Moreover, not all follicles reach the preovulatory phase and can be fertilized, so we will discuss how reproductive biotechniques can positively influence the fertility of bovine females. We will also discuss the possibility of antral follicle count to influence reproductive performance and the correlation to biotechniques. Finally, we present alternatives on how to improve fertility and productive efficiency in dairy herds

Puberty and parturition on the antral follicle count of female Nelore beef cattle.

The objective of this work was to investigate whether puberty and parturition alter the antral follicle count (AFC) in female Nelore (Bos indicus) beef cattle. Two experiments were carried out to compare AFC between the prepubertal and pubertal periods and between the prepubertal and postpartum periods. AFC and follicle concentrations did not differ between the prepubertal and pubertal periods. However, the ovarian area increased after puberty. In addition, AFC and the ovarian area were greater in the postpartum than in the prepubertal period. Therefore, AFC is not affected by the puberty of Nelore heifers, but increases significantly when the prepubertal heifers become cows. O objetivo deste trabalho foi avaliar se a puberdade e o parto alteram a contagem de folículos antrais (CFA) em fêmeas Nelore (Bos indicus) de corte. Foram realizados dois experimentos para comparar a CFA entre os períodos pré-púbere e púbere e entre os períodos pré-púbere e pós-parto. A CFA e a concentração folicular não diferiram entre os períodos pré-púbere e púbere. Entretanto, a área ovariana foi maior após a puberdade. Além disso, a CFA e a área do ovário foram maiores no período pós-parto quando comparado ao pré-púbere. Portanto, a CFA não é afetada pela puberdade de novilhas Nelore, mas aumenta significativamente quando as novilhas prépúberes se tornam vacas

Pure cerium dioxide preparation for use as spectrochemical standard and analysed by inductively coupled plasma mass spectrometry (SF ICP-MS)

Ao longo dos anos, o Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP) tem realizado diversas pesquisas na produção de Terras Raras (RE) de alta pureza. A metodologia apresentada neste trabalho refere-se à produção econômica e de baixo custo de óxido de cério. O cério produzido pode ser utilizado como um padrão espectroquímico. A obtenção desse padrão está associada à precipitação fracionada pelo sistema RECl3/NH4OH/Ar/H2O2, para enriquecer o óxido de cério de 90% a 99,99% em CeO2. O controle de qualidade do padrão produzido é feito através da técnica da espectrometria de massas com fonte de plasma (ICP-MS) e confirmado pela técnica da ativação de nêutrons. Os valores das impurezas de Terras Raras no óxido, em ppm são: La(36), Pr(19), Nd(161), Sm(11), Eu(5,3), Gd(113), Tb(89), Dy(2), Ho(0,05), Er(1), Tm(<0,05), Yb(11), Lu(19) e Y(2,1), respectivamente. Os valores encontrados das impurezas são comparados aos padrões internacionais e confirmam o alto nível de pureza do óxido de cério produzido no IPEN.For several years, IPEN/CNEN-SP has been working in the separation of the Rare Earth (RE) elements. A simple and economic procedure for the purification of technical grade cerium concentrate is described. The highly pure cerium dioxide is designed to be used as spectrochemical standard. It is obtained by association of the fractional precipitation technique, in the system RECl3/NH4OH/ Air/H2O2, to enrich the cerium up to 90% and then it is upgraded by ion exchange technique to 99.99% CeO2. The quality control warranty was accomplished by inductively coupled mass spectrometry (ICP-MS) and neutron activation analysis. The collected values for the accompanying Rare Earth elements in a CeO2 sample are the following (ppm): La(36), Pr(19), Nd(161), Sm(11), Eu(5.3), Gd(113), Tb(89), Dy(2), Ho(0.05), Er(1), Tm(<0.05), Yb(11), Lu(19) and Y(2.1), respectively. The purity of this cerium oxide is comparable to the international spectrographic standards

Relationship between follicle size and ultrasound-guided transvaginal oocyte recovery

We evaluated the relationship between follicle size and oocyte recovery (OR) using ultrasound-guided follicle aspiration. Thirty Holstein cows were subjected to OR without gonadotrophic therapy. Oocytes were recovered two to four times from each cow in a total of 67 aspiration sessions, Ovarian follicles with diameters less than or equal to4 mm and >4 mm were aspirated in separated groups. Recovered oocytes from each group were kept separate and submitted to in vitro maturation, fertilization, and culture to the blastocyst stage. A total of 430 follicles were aspirated, of which 154 (35.8%) were from follicles >4 mm and 276 (64.2%) were from follicles less than or equal to4 mm. Seventy-seven oocytes (50%) were recovered from follicles >4 mm and 200 (72.2%) were from follicles less than or equal to4 mm. Nineteen blastocysts were obtained from follicles >4 mm, whereas 45 blastocysts were obtained from follicles less than or equal to4 mm. Recovery rate was greater (P < 0.01) in follicles less than or equal to4 mm, Oocyte quality, cleavage rate and blastocyst development did not differ between different follicle sizes. Routine aspiration of small follicles (less than or equal to4 mm) could increase the number of oocytes available for in vitro development. (C) 2001 Elsevier B.V. B.V. All rights reserved