Genome-wide association study in thoroughbred horses naturally infected with cyathostomins.

Cyathostomins are considered one of the most important parasites of horses. A group of horses within a herd can be responsible for eliminating the majority of parasite eggs. This phenotype might be explained by genetic factors. This study aimed to identify genomic regions associated with fecal egg count (FEC) and hematological parameters by performing a genomic-wide association study (GWAS) in Thoroughbred horses naturally infected with cyathostomins. Packed cell volume (PCV), differential leukocyte, and FEC were determined from 90 horses. All animals were genotyped using the Illumina Equine 70 K BeadChip panel containing 65,157 SNP markers. The five genomic windows that have explained the highest percentage of the additive genetic variance of a specific trait (top 5) were further explored to identify candidate genes. A total of 33, 21, 30, 21, and 19 genes were identified for FEC, PCV, eosinophils, neutrophils, and lymphocyte count, respectively. The top 5 marker regions explained 2.86, 2.56, 2.73, 2.33, and 2.37% of the additive genetic variation of FEC, PCV, eosinophils, neutrophils, and lymphocytes count, respectively. This is the first study correlating phenotypic horse health traits to GWAS analysis, which may be used for animal breeding activities, reducing losses due to parasite infections.

Comparison of McMaster and Mini-FLOTAC fecal egg counting techniques in cattle and horses.

The aim of this study was to compare two fecal egg count (FEC) techniques; McMaster (McM) and Mini-FLOTAC (mF), for the detection of cattle and horse gastrointestinal nematode eggs, in different locations. Experiment 1: feces were collected from 16 cattle and FEC was performed individually, using mF with the sensitivity of 5 eggs per gram of feces (EPG) and McM with a sensitivity of 50 EPG at Empresa de Pesquisa Agropecuária de Minas Gerais - EPAMIG and the Laboratory of Parasitic Diseases of the University of Parana - LDP/UFPR. Experiment 2: Fecal samples from 30 horses were analyzed with mF (sensitivity of 5 EPG) and McM (sensitivity of 25 EPG) at the University of Mato Grosso do Sul - UFMS and LPD/UFPR. Experiment 3: feces were collected from 14 foals and FEC was performed using mF (sensitivity of 5 EPG); and McM (sensitivity of 25 EPG) only at the LPD/UFPR. For cattle, the average FEC of mF was 962 at LPD; and 1248 at EPAMIG; for McM it was 1393 at LPD and 1563 at EPAMIG. For horses, the FEC average using the mF was 650 at LPD and 469 at UFMS; and for McM it was 677 at LPD and 554 at UFMS. For foals, the average FEC for mF was 404 and 436 for McM. In all experiments, the standard deviation and the coefficient of variation values were significantly lower for mF. Therefore, it is recommended the use of the Mini-FLOTAC technique, which is a method with less variability and higher accuracy, particularly for animals with low FEC.

Efficacy of entomopathogenic bacteria for control of Musca domestica.

The aim of this study was to evaluate the larvicidal activity, and sub lethal effects of entomopathogenic bacteria Brevibacillus laterosporus, Bacillus thuringiensis var. israelensis, B. thuringiensis var. kurstaki, and a commercial formulation of Bacillus sphaericus on Musca domestica. Bacterial suspensions were prepared in different concentrations and added to the diet of newly-hatched larvae which were monitored until the adult stage. The larvae were susceptible to the B. laterosporus, B. thuringiensis var. israelensis, and B. thuringiensis var. kurstaki bacteria in varied concentration levels. These bacteria have larvicidal and sub lethal effects on the development of flies, reducing both adult size, and impairing the reproductive performance of the species.