Association of recombinant bovine somatotropin (rBST) with equine chorionic gonadotropin (eCG) on antral follicle count and oocyte production in Holstein and Tabapuã heifers

The objective of this study was to investigate whether the use of rbST and eCG prior to ultrasound-guided follicular aspiration (OPU) improves oocyte yield and quality in Tabapuã and Holstein heifers. The study was conducted in two phases, 20 days apart, in a change-over design. The dominant follicle was ablated two days (D-2) before two treatments: stimulation (6 Holstein and 8 Tabapuã), 500 mg of rbST (Boostin®) on D0 and 500 IU of eCG (Folligon) on D2; and control (6 Holstein and 8 Tabapuã), in which heifers received injections of the excipient. Heifers were aspirated on D4. Oocytes were subjected to a well established commercial in vitro embryo production protocol (Vitrogen®) and embryos were evaluated seven days after fertilization. There was an effect from the interaction of treatment and breed, so that hormonal stimulation increased antral follicle count (2-8 mm) in Tabapuã (29.9±2.6 to 41.4±2.6), but not in Holstein heifers (14.4±2.6 to 15.5±2.6). Tabapuã heifers had higher mean antral follicle count than Holsteins (35.6±1.8 vs. 15.0±2.1). The number of viable oocytes was not increased by stimulation in Tabapuã (from 4.7±1.0 to 5.2±1.1 in control and simulation, respectively) or in Holstein heifers (1.3±1.9 to 2.0±1.6 in control and simulation, respectively). There was no difference in the percentage of heifers with more than five viable oocytes in the group treated (33 vs 27%). The number of blastocysts was not affected by treatment (1.75 vs. 1.00 in hormonal stimulation and control, respectively). The increase in antral follicle count in the stimulated Tabapuã heifers did not reflect upon oocyte yield. The differential breed response to the hormonal treatment underscores the need for additional tests, especially for the Holstein breed, in order to enhance OPU efficiency

Características andrológicas e do sêmen de touros do composto Red Norte (Nelore x Tabapuã x Red Angus x Sinepol) Andrological and semen characteristics of cross-bred Red Norte (Nelore x Tabapuã x Red Angus x Sinepol) young bulls

Avaliaram-se as características andrológicas do sêmen de touros jovens do composto Red Norte (Nelore x Tabapuã x Red Angus x Sinepol), com idade média de 13,9±0,8 meses, com o objetivo de estimar o advento da puberdade e a qualidade do sêmen. Foram avaliados o perímetro escrotal (PE), o peso e as características seminais de 70 tourinhos, classificados em três grupos, de acordo com o PE: GI=27-33cm (n=24), GII=33-35cm (n=24) e GIII=35-43cm (n=22). As médias de peso e a idade de cada grupo (G) foram, respectivamente: GI=411,2±37,4kg e 13,8±1,0 meses, GII=426,9±31,5kg e 14,0±0,7 meses e GIII=438,4±38,3kg e 14,0±0,6 meses. As características seminais para cada grupo foram, volume 4,2±3,1mL, 5,3±2,6mL e 4,5±2,1mL; motilidade 31,3±24,1%, 44,2±23,9% e 43,9±21,5% e vigor 2,8±1,6, 3,5±1,3 e 3,5±1,3, respectivamente. O espermiograma apresentou valores médios de concentração de 130,5±266,2x10(6)/mL, 289,5±390,2x10(6)/mL e 333,9±523,7x10(6)/mL, defeitos totais de 81,4±15,9%, 73,8±15,4% e 67,9±19,0%; defeitos maiores de 87,3±26,2%, 66,8±24,9% e 56,7±17,1% e defeitos menores de 16,6±14,9%, 33,2±24,9% e 43,3±17,1%, respectivamente. Dos setenta animais examinados, sete (10%) foram considerados aptos à reprodução. Os resultados mostraram que a patologia espermática diminuiu em razão do aumento do PE.Reproductive traits of cross-breed Red Norte (Nelore x Tabapuã x Red Angus x Sinepol) young bulls averaging of 13.9±0.8 month-old were evaluated, in order to determine the puberty onset and semen quality in these animals. Scrotal circumference (SC), body weight (BW), and semen parameters of 70 bulls were measured. Animals were allotted in three groups (G) according to their SC: GI=27-33cm (n=24), GII=33-35cm (n=24), and GIII=35-43cm (n=22). BW and age of each group were, respectively: GI=411.2±37.4kg and 13.8±1.0 month-old, GII=426.9±31.5kg and 14.0±0.7 month-old, and GIII=438.4±38.3kg and 14.0±0.6 month-old. Seminal physical characteristics for same order of groups were: volume 4.2±3.1mL, 5.3±2.6mL, and 4.5±2.1mL; motility 31.3±24.1%, 44.2±23.9%, and 43.9±21.5%; and vigor 2.8±1.6, 3.5±1.3, and 3.5±1.3. The spermiogram presented concentration values of 130.5±266.2x10(6)/mL, 289.5±390.2x10(6)/mL, and 333.9±523.7x10(6)/mL; total defects of 81.4±15.9%, 73.8±15.4%, and 67.9±19.0%; major defects of 87.3±26.2%, 66.8±24.9% and 56.7±17.1%; and minor defects of 16.6±14.9%, 33.2±24.9%, and 43.3±17.1%, for same order of groups. Seven out of 70 bulls were considered satisfactory potential breeders. Results showed that semen pathology progressively decreased when SC increased

Phytohemagglutinin improves the development and ultrastructure of in vitro-cultured goat (Capra hircus) preantral follicles

The objective this study was to determine the effect of phytohemagglutinin (PHA) on survival, growth and gene expression in caprine secondary follicles cultured in vitro. Secondary follicles (&#8764;0.2&#8197;mm) were isolated from the cortex of caprine ovaries and cultured individually for 6 days in &#945;-MEM+ supplemented with PHA (0, 1, 10, 50, 100, or 200&#8197;&#181;g/mL). After 6 days of culture, follicle diameter and survival, antrum formation, ultrastructure and expression of mRNA for FSH receptors (FSH-R), proliferating cell nuclear antigen (PCNA), and neuronal nitric oxide synthase were determined. All treatments maintained follicular survival [&#945;-MEM+ (94.59%); 1&#8197;&#181;g/mL PHA (96.43%); 10&#8197;&#181;g/mL PHA (84.85%); 50&#8197;&#181;g/mL PHA (85.29%); 100&#8197;&#181;g/mL PHA (88.57%), and 200&#8197;&#181;g/mL PHA (87.50)], but the presence of 10&#8197;&#181;g/mL PHA in the culture medium increased the antrum formation rate (21.21%) when compared with control (5.41%, P < 0.05) and ensured the maintenance of oocyte and granulosa cell ultrastructures after 6 days of culture. The expression of mRNA for FSH-R (2.7 &#177; 0.1) and PCNA (4.4 &#177; 0.2) was also significantly increased in follicles cultured with 10&#8197;&#181;g/mL PHA in relation to those cultured in &#945;-MEM+ (1.0 &#177; 0.1). In conclusion, supplementation of culture medium with 10&#8197;&#181;g/mL PHA maintains the follicular viability and ultrastructure, and promotes the formation of antral cavity after 6 days of culture in vitro

Causes of rejection of beef bulls in breeding soundness evaluation

The objective of this study was to analyze the rates of rejection in the different steps of the breeding soundness evaluation of beef bulls in the state of Rio Grande do Sul, Brazil. The breeding soundness of 22,113 young and mature bulls of 14 beef breeds, participating in the Program of Reproductive Evaluation (PARTO) was evaluated in the experiment. Data concerning to the causes of rejection in the four steps of the breeding soundness evaluation (general physical examination, genital tract examination, semen evaluation and sexual behavior assessment) were analyzed by the Chi-square test and univariate regression analysis. According to year, general physical examination, genital tract examination and semen evaluation determined the rejection of 0.9% to 2.5%, 5.1% to 7.7%, 1.8% to 5.3%; and 4.2% to 6.7%, 7.3 to 9.3%, and 2.5% to 5.5% of young and mature bulls, respectively. Mature bulls presented higher chances of rejection than young bulls in the general physical examination in every year evaluated; as to the genital tract examination, their chances of rejection were higher in years I and II, but not in year III. In the semen evaluation, there was no difference between the ages assessed in any of the three years evaluated. Sexual behavior assessment accounted for the rejection of 1.9 to 6.0% of the young bulls and 2.9% to 3.9% of mature bulls, in accordance with the years evaluated; in years I and II, mature bulls presented higher rejection rates than young bulls. These results confirm the importance of performing all steps of the breeding soundness evaluation, including the sexual behavior assessment as a work routine, rather than an additional, optional stage of the evaluation, which should be carried out before the breeding season. The results indicate the relationship between bull age and rejection rate in the breeding soundness evaluation