Performance, carcass, and meat traits of locally adapted Brazilian cattle breeds under feedlot conditions.

Little is known about the performance, carcass, and meat traits of locally adapted cattle in Brazil. This study aimed to compare the growth, slaughter, and carcass traits as well as meat quality of two local breeds (Curraleiro Pé-Duro and Pantaneiro) with the Nelore breed. Fifteen 30-month-old steers of each breed were weighted (Curraleiro Pé-Duro = 264.80 kg; Nelore = 346.80 kg; Pantaneiro = 316.20 kg) and raised in a feedlot condition for 112 days, with measurements to assess growth and slaughter, visual and carcass and meat traits. Data were submitted to variance and multivariate analyses. Nelore and Curraleiro Pé-Duro had similar Gluteus medius depths. Pantaneiro and Curraleiro Pé-Duro were superior for leg compactness index (P < 0.05) and had higher eye muscle area than Nelore (P < 0.05). Although there was no difference in daily weight gain and slaughter weight between breeds, Curraleiro Pé-Duro had a lower initial weight (264.80 kg) when compared to Nelore (346.80 kg; P < 0.05). Nelore and Curraleiro Pé-Duro deposited more fat than Pantaneiro (P < 0.05), while Curraleiro Pé-Duro and Pantaneiro had more muscle than Nelore (P < 0.05), which also had more bone and a higher percentage of second-quality cuts (P < 0.05). Meat from Nelore also showed lower succulence than Pantaneiro (P < 0.05) and higher shear force than the other breeds (P < 0.05). Pantaneiro's meat had the most capacity to retain water (P < 0.05), lower shear force (P < 0.05), and was more succulent (P < 0.05) when compared to the other breeds. Multivariate analysis showed that Pantaneiro, Curraleiro Pé-Duro, and Nelore breeds can be considered distinct in growth, carcass, and meat traits, with the local breeds showing superior meat traits. The local breeds Curraleiro Pé-Duro and Pantaneiro presented characteristics similar or better to those of the Nelore, proving to be animals with great productive potential and generate high meat quality under feedlot conditions.

Protocolo com nove dias de progesterona para inseminação artificial em tempo fixo em vacas taurinas adaptadas ao clima tropical / Protocol with nine days of progesterone for fixed-time artificial insemination in Bos taurus cows adapted to the tropical weather

Três experimentos foram realizados para adaptar um protocolo de sincronização de estro e da ovulação para ser utilizado em programas de inseminação artificial em tempo fixo (IATF) em vacas taurinas tropicalmente adaptadas. No Exp. 1 (crossover), vacas pluríparas Curraleiro Pé-Duro (n= 12) receberam um dispositivo intravaginal contendo 1g de P4 por oito dias e 2mg de BE intramuscular (IM) no momento da inserção do dispositivo (dia 0). No dia da remoção do dispositivo (dia 8), as fêmeas receberam 150µg de D-cloprostenol sódico e 300UI de gonadotrofina coriônica equina (eCG) IM, sendo, então, divididas aleatoriamente para receber 1mg de BE no dia 8 (BE8) ou 1mg de BE no dia 9 (BE9). A aplicação de BE no D9 atrasou a ovulação em aproximadamente 15 horas (P<0,05). No Experimento 2, foram avaliados protocolos com oito (P4D8) e nove dias (P4D9) de exposição à progesterona, resultando em parâmetros de desenvolvimento folicular e luteal semelhantes entre os tratamentos (P>0,05). No Experimento 3, os protocolos hormonais de IATF BE8 e P4D9 foram testados para a taxa de prenhez, alcançando 23% (10/43) e 20% (9/45), respectivamente (P>0,05). Embora o grupo P4D9 tenha mostrado avanço na proporção de animais que responderam ao protocolo quando comparado ao protocolo BE8, este não se refletiu em melhora na taxa de prenhez.(AU)

Three experiments were performed to adapt a synchronization protocol of estrus synchronization and ovulation to be used in fixed time artificial insemination programs (FTAI) in tropically adapted Bos taurus cows. In Exp. 1 (crossover) multiparous Curraleiro Pé-Duro cows (n= 12) received an intravaginal device containing 1g of P4 for 8 days and 2mg of EB at the time of device insertion (Day 0). On the P4 device removal (Day 8) females received 150g of D-cloprostenol Sodic and 300IU of equine chorionic gonadotropin (eCG). Then, they were randomly divided to receive 1mg of EB on Day 8 (EB8) or on Day 9 (EB9). EB9 delayed ovulation approximately 15 hours (P<0.05). In Exp. 2, protocols using progesterone for eight (P4D8) or nine days (P4D9) were evaluated, resulting in similar parameters of folicular and luteal development (P>0.05). In Exp. 3, EB8 and P4D9 protocols were used to evaluate the pregnancy rate, reaching 23% (10/43) and 20% (9/45), respectively (P>0.05). Although P4D9 protocol has shown improvement in proportion of animals that responded to the protocol when compared to EB8 protocol, it was not able to improve pregnancy rate.(AU)

Plasminogen activator inhibitor 1 and Antipain preserve acrosome integrity of bovine spermatozoa during cryopreservation / Inibidor do ativador do plasminogênio 1 e antipaína preservam a integridade do acrossoma de espermatozoides bovinos durante a criopreservação

Seminal plasma contains serine proteases and serine protease inhibitor, which are involved in mammalian fertilization, and the inhibitors can be applied to prevent cold-induced sperm capacitation. The effects of different concentrations of two serine protease inhibitors were analyzed, Plasminogen activator inhibitor 1 - PAI-1 (70ƞg, 140ƞg and 210 ƞg) and Antipain (10µg, 50µg and 100µg) as supplementation to bovine semen cryopreservation extender. The effects of the inhibitors on the sperm parameters (sperm kinetics - CASA, acrosome integrity, plasma membrane integrity, mitochondrial membrane potential, sperm defects and acrosome reaction rate) were evaluated in the post-thaw semen. Cryopreservation of sperm with Antipain decreased post-thaw kinetic parameters of MP, VSL, LIN, SRT and the percentage of hyper-activated sperm while PAI-1 (210 ƞg) decreased VSL and LIN. Antipain and PAI-1 had no effect on the integrity parameters of the plasma membrane, mitochondrial membrane potential and sperm defects. Sperm cryopreserved in the presence of Antipain and PAI-1 (70 and 140 ƞg) preserved acrosome integrity, as they were able to complete the in vitro acrosome reaction. In conclusion, the serine protease inhibitors, Antipain and PAI-1 (70 and 140ƞg) are able to preserve the acrosome integrity of cryopreserved bovine sperm.(AU)

A criopreservação é parcialmente prejudicial à fertilidade do sêmen de bovinos e induz mudanças semelhantes à capacitação em espermatozoides. O plasma seminal contém serina-proteases e inibidores de serina-proteases que estão envolvidos na fertilização de mamíferos, e os inibidores podem ser aplicados para evitar uma capacitação espermática induzida pelo frio. Analisaram-se os efeitos de diferentes concentrações de dois inibidores de serina-proteases, inibidor do ativador do plasminogênio 1 - PAI-1 (70ƞg, 140ƞg e 210ƞg) e antipaína (10µg, 50µg e 100µg) na suplementação ao diluidor de criopreservação de sêmen bovino. Trinta e seis ejaculados de quatro bovinos Curraleiro Pé-Duro foram usados para criopreservação. Os efeitos dos inibidores sobre os parâmetros dos espermatozoides (cinética espermática - CASA, integridade acrossomal, integridade da membrana plasmática, potencial de membrana mitocondrial, defeitos espermáticos e taxa de reação acrossomal) foram avaliados no sêmen pós-descongelamento. A criopreservação de espermatozoides com antipaína diminuiu os parâmetros cinéticos pós-descongelamento de MP, VSL, LIN, SRT e a porcentagem de espermatozoides hiperativados, PAI-1 (210ƞg) diminuiu VSL e LIN. Antipaína e PAI-1 não tiveram efeitos nos parâmetros de integridade da membrana plasmática, no potencial de membrana mitocondrial e nos defeitos espermáticos. Espermatozoides criopreservados na presença de antipaína e PAI-1 (70 e 140ƞg) preservaram a integridade acrossomal, assim como foram capazes de completar a reação acrossômica in vitro. Em conclusão, os inibidores de serina-proteases, antipaína e PAI-1 (70 e 140ƞg) são capazes de preservar a integridade acrossomal de espermatozoides criopreservados de bovinos.(AU)

Characterizing emergence and divergence in the first follicular wave in a tropically adapted Bos taurus breed.

Tropically adapted Bos taurus breeds are descended from the cattle which were brought from the Iberian Peninsula to Latin America by the colonizers and which adapted over time to local conditions. These breeds have become a genetic treasure that must be preserved. The objective of this study was to characterize ovarian follicular emergence and divergence in tropically adapted B. taurus cows and heifers. Cyclic heifers (n = 11) and nonlactating, multiparous cows (n = 11) were examined at 8-hour intervals using ultrasonography starting on the day following the final application of PGF2α, which was used to synchronize the estrous cycle, and ending 5 days after ovulation. Blood samples were collected immediately following the ultrasonographic examinations in order to evaluate FSH and estradiol-17ß (E2) concentrations. The interval between ovulation and follicular wave emergence (11.6 ± 3.3 hours vs. 20.3 ± 2.5 hours, P < 0.05) and ovulation and follicular wave divergence (52.4 ± 5.2 hours vs. 71.8 ± 4.1 hours, P < 0.05) was shorter in the cows than in the heifers, respectively. Plasma FSH concentrations increased (P < 0.05) and serum E2 concentrations decreased earlier in cows than in heifers before ovulation. Following follicular wave emergence, no difference in follicular development was found between the cows and the heifers. Consequently, following follicular wave emergence, the data from both the cows and the heifers were combined and categorized by dominant follicle (DF) and second largest follicle (SF). The DF and SF were identified at the same time (P > 0.05). The mean number of small (≤4 mm, 7.2 ± 5.1) and medium (4 to ≤ 8 mm, 6.8 ± 3.5) follicles was greater than that of large follicles (≥8 mm, 0.6 ± 0.5) from ovulation until 5 days after ovulation. The DF diameter (8.1 ± 1 mm) did not differ (P = 0.09) from SF diameter (7.6 ± 0.9 mm) at the time of follicular divergence (around 45 hours after follicular emergence). The DF and SF growth rates were similar (P > 0.05) until follicular divergence, at which point the SF growth rate decreased, whereas the DF growth rate remained constant. Serum E2 concentrations did not change (P > 0.05) during the divergence period, whereas FSH concentrations decreased between 48 and 32 hours before follicular wave divergence. In conclusion, cows and heifers differed only in the interval from ovulation to follicular wave emergence and divergence, which was confirmed by the different patterns of FSH and E2 concentrations.