Presence of Trypanosoma vivax DNA in cattle semen and reproductive tissues and related changes in sperm parameters.

The present work investigated the presence of Trypanosoma vivax in semen and reproductive tissues of experimentally infected cattle and evaluated changes in seminal parameters. Two groups of cattle were established: T01 - experimentally infected with T. vivax (n = 8) and T02 - not experimentally infected with T. vivax (n = 8). After infection, blood (every seven days until 182 days post-infection - DPI), semen (7, 14, 35, 56, 70, 120 and 182 DPI) and reproductive tissue (after euthanasia, 182 DPI) were collected to search for T. vivax using different techniques, including PCR, Woo and Brener. Seminal parameters, including turbulence, motility, concentration, and vigor, were also analyzed. Packed cell volume (PCV) of the animals was determined weekly and weight gain was calculated. The PCR revealed T. vivax DNA in 7/56 semen samples of post-infection T01 cattle. Trypanosoma vivax DNA was detected in the semen of 5/8 animals at 7, 14, 56, 70 and 120 DPI, in the testis of four, and in the epididymis and fat located around the testis of two others. Trypomastigote forms of T. vivax were not found in any semen sample. Sperm of T01 cattle had lower turbulence (p ≤ 0.05) at 7, 14, 35, 56, 120 and 182 DPI, lower vigor (p ≤ 0.05) at 120 DPI and more sperm abnormalities (p ≤ 0.05) than T02. Digital dermatitis was observed among T01 cattle. Animals of T01 had lower PCV values than did those of T02 for most of the evaluations performed and T02 animals gained more weight during the experiment. The results highlight the presence of T. vivax DNA in semen of infected cattle and the importance of this disease for male breeding cattle. Further research is needed to determine whether T. vivax can be sexually transmitted in cattle.

Population Structure of Curraleiro Pé-Duro Cattle and its Relationship With the Serological Profile Against Pathogens of Economic and Zoonotic Interest.

Curraleiro Pé-Duro (CPD) cattle, a Brazilian local breed, are animals that are highly resistant to infectious and parasitic diseases. Strategies for the conservation of the breed and the genetic resistance to diseases should also consider the characteristics of the breed. The objective of this study was to analyze the diversity and population structure of the CPD breed using microsatellite markers and to correlate the serological profiles for causative agents of brucellosis, leptospirosis, neosporosis, leukosis, infectious bovine rhinotracheitis, and bovine viral diarrhea. DNA samples of 608 bovines were amplified and genotyped using 28 microsatellite markers for breed characterization. The genotypes were assigned to three clusters, indicating a substructure population related to the geographic distance. The observed heterozygosity was lower than that expected in most loci, and fixation index (Fst) in the subpopulation values ranged from 0.03073 (ETH3) to 0.402 (INRA63) on cluster 1, from 0.00 (INRA32) to 0.39359 (INRA63) on cluster 2, and from 0.00 (INRA32) to 0.28483 (TGLA53) on cluster 3. The Brucella spp., Neospora caninum, and Bovine Leukemia Virus frequencies were significantly different (p < 0.05) between clusters. The differences between the occurrences of diseases were not sufficient to indicate a genetic subpopulation with increased resistance to infections.

Effect of biotin supplementation on claw horn growth in young, clinically healthy cattle.

The effects of orally administered biotin supplementation on the growth of claw horn in young, clinically healthy cattle were analyzed. Twelve, 1-year-old Girolando cattle were randomly assigned to receive either 12.5 mg of diluted powdered biotin (GI) or a control treatment (GII) for 40 consecutive days. Cattle in the GI group showed an average hoof growth of 11.3 +/- 0.72 mm, while those in GII had an average hoof growth of 7.2 +/- 0.78 mm. The results confirmed the positive effect of biotin supplementation on the growth of angle and length of the dorsal hoof wall, hoof sole length, and on resistance to wearing, in young cattle extensively managed.