Suchergebnisse

This study aimed to evaluate the performance, carcass characteristics, serum parameters, the residual depletion in the beef and the economic viability of termination steers with salinomycin in the diet. Were confined 32 animals fed with diet consisting of corn silage and concentrate (50:50) or not added salinomycin (120 mg animal d-1). The design was completely randomized with 8 repetions. The use of salinomycin improved weight gain (1.582 vs 1.304 kg) and feed conversion (6.16 vs 7.25 kg kg-1). There were no significant changes in feed intake (9.52 vs 9.25 kg animals d-1) in serum parameters, nor in the apparent digestibility of the diet. The 16-hour grace period before slaughter expressed salinomycin concentrations below 0.25 µg kg-1 in the organs and edible tissues below the values allowed by law. Animals finished with salinomycin showed better hot carcass weight (287.76 vs 275.81 kg) and better economic results, an increase of R$ 84.20 per animal in the profit margin. The use of salinomycin for feedlot steers promoted improvements in the production and economic performance without harming the health of animals and consumers, because they were not detected significant residues in edible tissues

The use of diets without roughage in beef feedlot has become common in recent years due to practicality, feasibility and availability of inputs. However, the introduction of roughage that does not harm the operation of the feeding management can bring health benefits to animals and economic gain. This study aimed to evaluate the productive and economic performance of steers finished in feedlot, fed three levels of sugar cane bagasse pellets (SBP) in diets without long-fiber. The treatments consisted of 0%, 7% and 14% of SBP in a mixture of concentrate, comprising 80% whole corn grain plus 20% of a protein core. The experimental design was completely randomized with four replications. The diet with 0% of SBP promoted lower dry matter intake and weight gain. Feed conversion was similar between treatments, with an average of 6.21 kg-1. The lower dry matter digestibility was found in the diet with 14% of SBP. The introduction of SBP did not change the rumination, averaging 1.9 hours day-1. Animals fed 7% of SBP showed higher fat thickness. Due to the numerical differences between treatments for feed conversion in housing and daily cost of food, the profit margin was maximal in the diet with 0% of SBP, with values of R$ 338.1; R$ 311.6 and R$ 305,1 per animal, respectively 0%, 7% and 14% of SBP. The introduction of SBP promoted improvements in production performance, but did not improve the economic results of steers finished in feedlot.

This study emphasized the importance of using candidate genes in predicting semen quality in bulls that can be used in cow-calf production. The aim of this study was to evaluate some candidate genes related to reproductive traits in Braford and Hereford bulls. All bulls (n=188) were submitted to breeding soundness evaluations at 24, 28, 32, and 36 months of age. The microsatellite markers ILSTS002 and BMS3004 associated with the luteinizing hormone-? (LH?) gene, IDVGA-51 to leptin (LEP) gene, HEL5 and AFZ1 within the IGF-IR gene, and two SNP markers (LHR and FSHR) associated with the LHR and FSHR genes, respectively, were evaluated by the amplification of DNA products. The variation in the IDVGA-51 allele 177-185 showed polymorphic information content (PIC) associated with sperm motility and vigor traits in Hereford bulls. Hereford animals showed PIC of 0.36 to 0.75% along with expected heterozygosity (H) of 0.49 to 0.78%. Braford bulls that indicated the ILSTS002 allele 137-175 and AFZ1 allele 113-119 showed PIC associated with major and minor defects, respectively. The PIC ranged from 0.28 to 0.78%, with an expected H of 0.35 to 0.81%. AFZ1 allele 121-127 had the highest minor defects and ILSTS002 allele 125-135 showed the highest major defects from ejaculated semen in Braford bulls. In addition, IDVGA-51 allele 175 showed lower motility and vigor in Hereford bulls. The markers AFZ1 (IGF-IR) and ILSTS002 (LH?) in Braford and IDVGA-51 (LEP) in Hereford bulls were effective in verifying the reproductive traits of the bulls.

The aim of this study was to evaluate the dynamics of the scrotal temperature, sperm quality and testicular blood flow by using infrared thermography and Doppler ultrasonography in bulls submitted to scrotal insulation. Braford bulls (n = 8) at 18 months of age, were assigned into the following groups: insulated for 72 h (G 72; n = 2), 96 h (G 96, n = 2), 120 h (G 120, n = 2), and control animals (CON; n = 2) that remained without insulation. Infrared thermography and Doppler ultrasonography parameters were measured at four different time points: immediately after the scrotal insulation (M0), within 10 min (M10), 30 min (M30) and 60 min (M60) after scrotal insulation. The sperm quality was evaluated weekly (S1/S12). The data were analyzed by ANOVA, t-test (paired) and Pearson's correlation with a significance level of 5%. None of the observed variables were different between the insulated groups (P > 0.05). Insulated animals showed higher scrotal temperature in M0 compared to that in the M10, M30 and M60 periods (P < 0.05). There was no difference in the pulsatility and resistive indexes after scrotal insulation. However, blood flow velocity was higher in M10 compared to that in the M0, M30 and M60 periods (P < 0.05). The sperm quality was higher (P < 0.05) in all twelve collections from the control group compared with the insulated groups. Scrotal insulation resulted in changes in the sperm quality, scrotal temperature and testicular blood flow velocity.

The goal of this study was to evaluate the rejection rates of Zebu bulls during behavioral assessment (libido and serving ability) and the importance of this step in bull breeding soundness evaluation (BBSE). A total of 1,534 bulls reared in the state of Rio Grande do Sul, Brazil, of Nelore (1,340), Brahman (76), Guzerá (98), and Tabapuã (210) breeds were evaluated. The evaluation consisted of four steps. Step I was the general physical examination, Step II genital tract examination, Step III semen evaluation, and Step IV behavioral assessment of libido and the ability to complete copulation. To evaluate the relationship between the binary variables of approved or rejected during different steps of the BBSE, and age groups (young and mature bulls), chi-square tests and logistic regression were used. The general rejection rates in the BBSE were 5.64% and 15.20% for young and mature Zebu bulls, respectively. Problems with the sexual behavior (libido and/or serving ability) of bulls accounted for the rejection of 0.46% and 2.29% of young and mature Zebu bulls, respectively. The lack of libido and serving ability was shown to be an important problem concerning the total number of possible causes of Zebu bull rejection during the BBSE. This result suggests that the behavioral step should be performed regularly, rather than being complementary to the standard BBSE in Zebu cattle.