Luteinizing hormone secretion, ovulatory capacity, and oocyte quality in peripubertal Gir heifers.

Induction of puberty in cattle breeds that attain puberty in later stages, such as Gir, allows the earlier beginning of reproductive life and it might increase oocyte quality. Here, the ovulatory capacity of prepuberal Gir heifers was studied and its relationship to follicular growth, luteinizing hormone (LH) secretion and oocyte quality was evaluated. Peripubertal Gir heifers were treated with a progesterone-based protocol and according to ovulatory response were separated into groups: not-ovulated (N-OV) and ovulated (OV). Serial blood samples were taken 24 h after estradiol treatment on day 12 to evaluate LH secretion. Cumulus-oocyte complexes (COCs) were collected using ovum pick-up and assessed for brilliant cresyl blue (BCB) staining rate, IVF-grade oocytes rate, and mean oocyte diameter, in comparison with cow oocytes. Gene expression of developmental competence markers (ZAR1, MATER, and IGF2R) was also analyzed. The largest follicle diameters were similar between N-OV and OV groups on the day of estradiol treatment (d12) and the next day and decreased (P = 0.04) in the N-OV group thereafter. LH pulse secretion was different between groups (N-OV = 3.61 ± 0.34 vs OV = 2.83 ± 0.21 ng/ ml; P = 0.04). COC assessment showed that the number of recovered oocytes, BCB+ rate, IVF-grade oocytes and oocyte size was similar (P > 0.05) among groups, resembling adult cow patterns. ZAR1, MATER and IGF2R gene expression in oocytes were also similar (P > 0.05) in N-OV and OV groups. In conclusion, our results demonstrate a lower LH secretion profile in peripubertal Gir heifers prone to ovulate after induction protocol, and that oocyte quality is not affected on a short-term basis by ovulation itself.

Validation of a real time PCR for classical Swine Fever diagnosis.

The viral disease classical swine fever (CSF), caused by a Pestivirus, is one of the major causes of economic losses for pig farming. The aim of this work was to validate a RT-qPCR using Taqman for detection of CSF in swine tissues. The parameters for the validation followed the specifications of the Manual of Diagnostic Tests and Vaccines for Terrestrial Animals of the World Organization for Animal Health (OIE) and the guide ABNT NBR ISO/IEC 17025:2005. The analysis of the 5'NTR region of CSF virus was performed in 145 samples from 29 infected pigs and in 240 samples from 80 pigs originated in the Brazilian CSF-free zone. The tissues tested were spleen, kidney, blood, tonsils, and lymph nodes. Sequencing of the positive samples for 5'NTR region was performed to evaluate the specificity of the RT-qPCR. Tests performed for the RT-qPCR validation demonstrated that the PCR assay was efficient in detecting RNA from CSF virus in all materials from different tissues of infected animals. Furthermore, RNA from CSF virus was not detected in samples of swine originated from the Brazilian CSF-free zone. Hence, it is concluded that RT-qPCR can be used as a complementary diagnostic for CSF.

Desempenho de novilhas Holandês na produção de embriões F1 Holandês-Zebu, em condições tropicais / Performance of Holstein heifers for F1 Holstein-Zebu embryo production, in tropical conditions

A produção in vivo de embriões bovinos é uma alternativa para a formação e manutenção de rebanhos mestiços F1 destinados à produção de leite. Objetivou-se estudar o potencial de utilização de novilhas da raça Holandês, mantidas em pasto e suplementadas, como doadoras de embrião, nas épocas de verão e inverno. Procederam-se superovulação e coleta de embriões em sete novilhas em cada época. Foram obtidos os dados climáticos, a temperatura retal e a frequência respiratória das doadoras. No verão, observou-se maior índice de temperatura e umidade (ITU) às 6h, 12h e 18h, bem como maior (P0,05) na média de estruturas recuperadas (20,14±17,47 vs. 8,57±9,40), embriões viáveis (14,57±11,91 vs. 7,14±7,24) e congeláveis (13,28±11,39 vs. 6,57±6,24) obtidos no inverno e no verão, respectivamente. Sob as condições estudadas, novilhas da raça Holandês podem ser utilizadas para a produção de embriões F1, tanto no verão, quanto no inverno.

In vivo embryo production (embryo transfer) is an alternative for F1 dairy herds formation and maintenance. The aim of this study was to evaluate the potential of utilization of grazing and supplemented Holstein heifers as embryo donors in summer or winter. Superovulation was performed in seven heifers on each season. Climatic parameters, as well as rectal temperature and respiratory rate of donors were measured. Temperature and humidity index (THI) was higher (p0.05). Holstein heifers can be used as embryo donors in both summer and winter, under the given conditions.