Characterization of antral follicle populations during the estrous cycle in pigs selected for ovulation rate

The objectives of this study were to characterize and compare ovarian follicular populations in Gene Pool Control (GPC, randomly selected) and Relax Select line (RS, nine generations of selection for high ovulation rate followed by six generations of random selection) gilts during different stages of the estrous cycle. Thirty-five RS and 23 GPC gilts were allotted randomly within litter for ovary recovery on either d 3, 15 or 19 of the estrous cycle. Surface follicles on the ovaries were classified by size (small, less than 3 mm; medium, 3 to 6.9 mm; large, 7 to 12 mm), and counts were recorded for each ovary. Ovarian weight (OW), number of corpora lutea (CL), follicular fluid volume (FFV) from small, medium and large follicles, residual ovarian weight and follicular fluid weight (FFW) also were recorded. Total numbers of small and medium follicles were greatest on d 15, whereas total number of large follicles and FFW were greatest on d 19. The OW, FFW and follicle numbers of all classes were lowest on d 3. The RS gilts expressed longer interestrous intervals (21.9 vs 20.4 d, P less than .05) and higher ovulation rates (18.5 vs 15.3 CL, P less than .01) than GPC gilts. The left ovary of RS gilts was responsible for most of the ovulation rate advantage (10.3 vs 7.4 CL, P less than .01) Overall, GPC gilts had more total small follicles than RS gilts (P less than .01). The advantage was due primarily to higher numbers of small follicles at d 15.(ABSTRACT TRUNCATED AT 250 WORDS)     

Anthelmintic efficacy of netobimin against naturally acquired gastrointestinal nematodes in yearling heifers

The efficacy of netobimin (Coded SCH 32481, Schering Corporation) in removing naturally acquired gastrointestinal nematode infections was evaluated in 10 treated and 10 untreated (control) yearling beef heifers. The anthelmintic was administered as an oral drench at a dose level of 7.5 mg kg-1 body weight. Fecal egg per gram (EPG) counts were reduced with netobimin by 98% (P less than or equal to 0.01) at both 1 and 2 weeks post-treatment (PT). The compound was highly effective in removing Oesophagostomum radiatum (100% at P less than or equal to 0.01), Cooperia spp. (97.66% at P less than or equal to 0.01) and Nematodirus helvetianus (100%, although not significant), but was ineffective against immature Ostertagia ostertagi (3.19%) and only moderately effective against adult forms (66.14% at P less than or equal to 0.05). The low efficacy against adult O. ostertagi was partially attributed to the maturation of fourth-stage larvae, not removed by the 7.5 mg kg-1 treatment, during the 14-day treatment-slaughter interval. Efficacy against Trichuris spp. could not be evaluated due to low levels and unequal numbers of worms recovered in the groups. The overall efficacy against adult species, excluding Trichuris spp., was 67.40% (P less than or equal to 0.05). No adverse reactions or signs of toxicosis were observed in heifers treated with netobimin.     

Effect of temperature and relative humidity on the stability of infectious porcine reproductive and respiratory syndrome virus in aerosols

The objective of this experiment was to describe the stability of airborne infectious porcine reproductive and respiratory syndrome virus (PRRSV) as a function of temperature and relative humidity. A cloud of infectious PRRSV was aerosolized using 24-jet Collison nebulizer into a dynamic aerosol toroid (DAT) maintained at a specific temperature and relative humidity. The PRRSV cloud within the DAT was sampled repeatedly over time using SKC BioSampler impingers and the total viral RNA (RT-PCR) and concentration of infectious PRRSV (TCID50) in the air samples was determined. As measured by quantitative RT-PCR, PRRSV RNA was stable under the conditions evaluated in this study. Thus, a comparison of viral RNA and Rhodamine B dye, a physical tracer, found no significant difference in the slopes of the lines. Titers of infectious virus were plotted by time and the half-life (T1/2) of infectious PRRSV was calculated using linear regression analysis. An analysis of the results showed that aerosolized PRRSV was more stable at lower temperatures and/or lower relative humidity, but temperature had a greater effect on the T1/2 of PRRSV than relative humidity. Based on these results, an equation was derived to predict the T1/2 of infectious airborne PRRSV for any combination of environmental temperature and relative humidity.     

Estimating the mass of asteroid 253 mathilde from tracking data during the NEAR flyby

The terminal navigation of the Near Earth Asteroid Rendezvous (NEAR) spacecraft during its close flyby of asteroid 253 Mathilde involved coordinated efforts to determine the heliocentric orbits of the spacecraft and Mathilde and then to determine the relative trajectory of the spacecraft with respect to Mathilde. The gravitational perturbation of Mathilde on the passing spacecraft was apparent in the spacecraft tracking data. As a result of the accurate targeting achieved, these data could be used to determine Mathilde's mass as 1.033 (+/- 0.044) x 10(20) grams. Coupled with a volume estimate provided by the NEAR imaging team, this mass suggests a low bulk density for Mathilde of 1.3 grams per cubic centimeter.     

Temporal and spatial dimension of dissolved oxygen saturation with fluidic oscillator and Mazzei air injector in soil-less irrigation systems

The wider scale use of aerated water for irrigation has been limited by dis-uniformity of aeration in the field, limited longevity of oxygen in irrigation water and lack of knowledge of what oxygen concentration brings optimal growth. Two options are presented for increasing dissolved oxygen (DO) in irrigation water: Venturi (VT) and fluidic oscillator (FO) aeration systems. Sweet corn was grown in pots to evaluate the effect of aerated water. Compared to the control treatment (CK), VT and FO showed an increase in irrigated water DO in the irrigation tank and feeding pots after aeration. Incorporation of surfactant in the irrigation water significantly improved DO level for the VT and FO treatment. Typically the DO levels reached a peak when the pump is turned off and then decline to a minimum after 24 h. The VT and FO systems had a higher magnitude and duration of the DO level in the water in all treatments compared to the CK system. The FO aeration maintained the longest duration of elevated DO in the water by a factor of two compared to the VT aeration. Compared to the CK, the best result on longevity and DO concentration was achieved using 4 ppm of a non-ionic surfactant. The corn biomass was significantly greater for the VT compared to both the FO and CK treatments.     

Enhancing the effectiveness of biological control programs of invasive species through a more comprehensive pest management approach

Invasive species are one of the greatest economic and ecological threats to agriculture and natural areas in the US and the world. Among the available management tools, biological control provides one of the most economical and long‐term effective strategies for managing widespread and damaging invasive species populations of nearly all taxa. However, integrating biological control programs in a more complete integrated pest management approach that utilizes increased information and communication, post‐release monitoring, adaptive management practices, long‐term stewardship strategies, and new and innovative ecological and genetic technologies can greatly improve the effectiveness of biological control. In addition, expanding partnerships among relevant national, regional, and local agencies, as well as academic scientists and land managers, offers far greater opportunities for long‐term success in the suppression of established invasive species. In this paper we direct our recommendations to federal agencies that oversee, fund, conduct research, and develop classical biological control programs for invasive species. By incorporating these recommendations into adaptive management strategies, private and public land managers will have far greater opportunities for long‐term success in suppression of established invasive species. © 2016 Society of Chemical Industry