Estimation of inbreeding and effective population size of full‐blood wagyu cattle registered with the American Wagyu Cattle Association

The objective of this research was to examine the population structure of full‐blood (100%) Wagyu cattle registered in the United States with the American Wagyu Association, with the aim of estimating and comparing the levels of inbreeding from both pedigree and genotypic data. A total of 4132 full‐blood Wagyu cattle pedigrees were assessed and used to compute the inbreeding coefficients (F_IT and F_ST) and the effective population size (N_e) from pedigree data for the period 1994 to 2011. In addition to pedigree analysis, 47 full‐blood Wagyu cattle representing eight prominent sire lines in the American Wagyu cattle population were genotyped using the Illumina BovineSNP50 BeadChip. Genotypic data were then used to estimate genomic inbreeding coefficients (F_ROH) by calculating runs of homozygosity. The mean inbreeding coefficient based on the pedigree data was estimated at 4.80%. The effective population size averaged 17 between the years 1994 and 2011 with an increase of 42.9 in 2000 and a drop of 1.8 in 2011. Examination of the runs of homozygosity revealed that the 47 Wagyu cattle from the eight prominent sire lines had a mean genomic inbreeding coefficient (F_ROH) estimated at 9.08% compared to a mean inbreeding coefficient based on pedigree data of 4.8%. These data suggest that the mean genotype inbreeding coefficient of full‐blood Wagyu cattle exceeds the inbreeding coefficient identified by pedigree. Inbreeding has increased slowly at a rate of 0.03% per year over the past 17 years. Wagyu breeders should continue to utilize many sires from divergent lines and consider outcrossing to other breeds to enhance genetic diversity and minimize the adverse effects of inbreeding in Wagyu.     

Effect of Suppression of FSH with a GnRH Antagonist (Acyline) Before and During Follicle Deviation in the Mare

A GnRH antagonist (Acyline) was used to study the role of FSH in early development of a follicular wave in 61 mares. In Experiment 1, a single dose of 3 mg per mare, compared with 0 and 1 mg, suppressed both the FSH and follicle responses to exogenous GnRH. In Experiment 2, high concentrations of FSH were induced by two successive ablations of all follicles ≥ 6 mm on days 10 and 13 (day 0 = ovulation). A single treatment with Acyline resulted in significantly greater suppression of plasma concentrations of FSH than a single treatment with charcoal-extracted follicular fluid (source of inhibin) or oestradiol. Suppression of FSH was not significantly different between the group treated with Acyline alone and a group treated with a combination of Acyline, inhibin and oestradiol. In Experiment 3, all follicles were ablated on day 10 to induce an FSH surge and a new follicular wave. Acyline treatment on day 10 resulted in an immediate decrease in FSH, without a significant effect on day of emergence of a new wave or growth of follicles from 7 to 11 mm on days 11–13. Treatment on day 15, a day before expected follicle deviation and after the peak of the wave-stimulating FSH surge, resulted in an immediate decrease in FSH and cessation of follicle growth. Results indicated that growth of follicles for about 2 days after wave emergence was independent of FSH. In contrast, during the decline in the wave-stimulating FSH surge and before follicle deviation, growth of follicles was dependent on FSH.     

Effect of hCG in the Presence of hCG Antibodies on the Follicle, Hormone Concentrations, and Oocyte in Mares

Follicle blood flow, follicular-fluid and plasma hormone concentrations, and oocyte quality were studied 30 h after an ovulation-inducing hCG treatment when the pre-ovulatory follicle was 32 mm. Mares were grouped as positive (n = 16) and negative (n = 44) for hCG antibodies before the experimental hCG treatment. Percentage of the follicle wall with blood flow signals was less (p < 0.05) in the antibody positive group than in the negative group. The concentrations of follicular-fluid oestradiol and free IGF1, and plasma oestradiol were greater (p < 0.001), and follicular-fluid progesterone (p < 0.001) and plasma LH (p < 0.02) were less in the antibody-positive group than in the negative group. For recovered oocytes at 30 h (n = 37), the antibody-positive group had fewer (p < 0.001) mature (MII) oocytes than the antibody-negative group. Results were attributable to highly effective neutralization of the hCG in the antibody-positive group.     

Follicle Deviation in Ovulatory Follicular Waves with One or Two Dominant Follicles in Mares

The follicle and hormone aspects of diameter deviation and development of one dominant (≥28 mm) follicle (1DF) vs two dominant follicles (2DF) were studied in 32 ovulatory follicular waves in mares. Follicles were ranked each day as F1 (largest) to F3. The beginning of deviation was designated day 0 and preceded the first increase in the differences in diameter between F1 and F2 in the 1DF group and between a combination of F1 and F2 vs F3 in the 2DF group. One dominant follicle and 2DF developed in 21 (66%) and 11 (34%) waves, respectively. Double ovulations occurred in only one of the waves with 2DF. In 8/11 waves with 2DF, a second deviation occurred between F1 and F2 on 2.5 ± 0.4 days after the first deviation. On day 0, 1DF and 2DF waves were similar in number of days after ovulation, number of follicles, difference in diameter between F1 and F2, and plasma concentrations of LH, estradiol and immunoreactive inhibin. The interval from maximum FSH concentration to day 0 was longer (p < 0.05) and FSH concentration was lower (p < 0.05) on days -1 to 4 in the 2DF group. The similarities on day 0 in the characteristics of 1DF and 2DF waves despite the differences in the declining portions of the FSH profile indicated that a specific day of the FSH decline or a specific concentration were not factors in initiating deviation. Unlike reported results in heifers, the results in mares did not indicate a hormonal basis for the development of 2DF or two deviations.     

Resistance of Triticum dicoccoides to infection with Erysiphe graminis tritici

Summary The reactions of 233 Triticum dicoccoides acessions, collected at 10 sites in Israel and elsewhere, to infection with cultures of Erysiphe graminis tritici, were determined. The reactions indicated that the number of sources of resistance to E. graminis tritici which can be obtained from T. dicoccoides plants growing wild in Israel and elsewhere is almost unlimited. One hundred and fourteen or 49% of the accessions were resistant, and 137 or 59% of the accessions were resistant or moderately resistant to infection with four cultures of E. graminis tritici which possess the virulence genes corresponding to most of the identified resistance genes in wheat. Accessions collected at sites with marginal habitats where T. dicoccoides grows poorly and has lower grain weight, were more susceptible than were accessions collected at sites with an optimal habitat for growth of T. dicoccoides. The results agreed with those in a previous study with Hordeum spontaneum, and indicate that to obtain H. spontaneum or T. dicoccoides accessions with the highest level of resistance to the powdery mildew pathogens, plants should be collected at sites in ecological and geographic regions where those two species occupy optimum habitats and are exposed to the powdery mildew pathogens.     

Determination of deltamethrin in cattle dipping baths by high-performance liquid chromatography

Deltamethrin (S)-alpha-cyano-3-phenoxybenzyl) (1R,3R)-3-(2, 2-dibromovinyl)-2,2-dimethylcyclopropane-1-carboxylate is classified as a pyrethroid pesticide that is largely used as an acaricide and scabicide. For bovines, especially, the treatment is done with the aid of dipping baths of the pyrethroid solution. Analytical control of the concentration of deltamethrin in these baths must be done periodically in order to guarantee treatment efficacy. In the proposed procedure, the sample is prepared by centrifugation followed by filtration and measurement by high-performance liquid chromatography (HPLC) with spectrophotometric detection at 275 nm. Separation is done in a Nucleosil C-18 column with acetonitrile-water as the mobile phase. A calibration curve was constructed with external standards, and a detection limit of 0.2 mg L(-)(1) was obtained. In the samples analyzed, only ca. 20% of the total deltamethrin content was found in the solution. The results obtained demonstrate the potential of the described procedure for the determination of deltamethrin in animal baths.     

THE INFLUENCE OF IRON AND ALUMINIUM HYDROXIDES ON THE SWELLING OF Na-MONTMORILLONITE AND THE PERMEABILITY OF A Na-SOIL

Hydroxy Fe and A1 interlayers reduce the swelling of Na-montmorillonite in NaCl solutions. A deposit of sesquioxide round an aggregate or orientated flake of clay restricts swelling until the sesquioxide coating is broken by the swelling pressure of the clay. A1 is more effective than Fe. The effect of sesquioxides on the permeability to NaCl solutions of an alkali soil depends on the control of clay swelling in a manner expected from the above results. A sesquioxide coating round a soil aggregate stabilizes the structure until the coating is broken by the swelling pressure of the clay in the aggregate.     

Serological status of cattle to bovine viral diarrhoea virus and bovine herpesvirus 1 at entry to and exit from Australian feedlot backgrounding facilities

A total of 6195 cattle were enrolled in this observational study. Serum antibody concentrations to bovine herpesvirus 1 (BHV1) and bovine viral diarrhoea virus (BVDV) were measured at entry to and exit from backgrounding facilities to assess their statuses on arrival and the extent of seroconversion to these viruses during backgrounding. The backgrounding facilities were contiguous with five feedlots in: Queensland (two sites), New South Wales, South Australia and Western Australia. Cattle were held in the backgrounding facilities for a minimum of 29 days and a median of 34 days. On backgrounding facility entry, 32.7% of the study population was seronegative to BVDV, but 85.7% was seronegative to BHV1. After commingling in the backgrounding facilities, of the cattle that were seronegative on backgrounding facility entry, 33.9% and 30.3% showed a serological increase to BVDV and BHV1, respectively. At backgrounding facility exit, when cattle were placed in their feedlots, 19.6% and 59.1% were seronegative to BVDV and BHV1, respectively, and 0.26% were persistently infected with BVDV. There was a strong association between seroincrease to BVDV and seroincrease to BHV1 (P = 0.005) at animal level in cohorts known to contain an animal persistently infected with BVDV.