Effects of nematicides on nematode population densities and crop yield in a turnip-corn-pea cropping system

Nous avons évalué quatre systèmes de conduite de cultures lors d'une étude de 6 ans afin de lutter contre les nematodes dans un système annuel de production de navet-maïs-pois sur des parcelles de sable loameux Tifton naturellement infestées par les Meloidogyne spp. (environ 90 % de M. incognita et 10 % de M. hapla), les Pratylenchus spp. (environ 65 % de P. scribneri, 25 % de P. brachyurus et 10 % de P. zeae), ainsi que par les Paratrichodorus minor et Criconemella ornata. Le navet (Brassica campestris subsp. rapifera) a toléré de faibles quantités de tous les nematodes. Le maïs (Zea mays) 'Pioneer 3369A' a toléré de plus importantes quantités de tous les nematodes que le maïs 'Funks G-4507'. Les densités de population de juvéniles (J2) de Meloidogyne spp. ont été abaissées en deçà de 80 par 150 cm3 de sol par un mélange composé de 98 % de bromure de méthyle et 2 % de chloropicrine et par 20% de methyl isothiocyanate combiné à 80% d'hydrocarbones C3 chlorinés sur le navet et le maïs. Ces populations de nematodes ont augmenté rapidement chez le pois (Vigna unguiculata) 'Pinkeye purplehull' mais ce ne fut pas le cas chez le cultivar Worthmore. Les densités de populations des autres nematodes n'ont pas été affectées par le cultivar de pois ou par le nématicide, en l'occurrence l'ethoprop. Le fenamiphos a été plus efficace que l'ethoprop en abaissant les densités de nematodes. Les augmentations de rendement du système intensif de conduite des cultures se sont échelonnées de 4% à 52 % par rapport aux témoins non traités.Four management systems were evaluated in a six-year study to control nematodes in a turnip-corn-pea annual cropping System on plots of Tifton loamy sand naturally infested with Meloidogyne spp. (about 90 % M. incognita and 10% M. hapla), Pratylenchus spp. (about 65% P. scribneri, 25% P. brachyurus, and 10% P. zeae), Paratrichodorus minor and Criconemella ornata. Turnip (Brassica campestris subsp. rapifera) supported low numbers of all nematodes. 'Pioneer 3369A' corn (Zea mays) supported greater numbers of all nematodes than 'Funks G-4507'. Population densities of Meloidogyne spp. juveniles (J2) were suppressed below 80 per 150 cm3 of soil by 98 % methyl bromide + 2 % chloropicrin and 20 % methyl isothiocyanate + 80 % chlorinated C3 hydrocarbons on turnip and corn, and increased rapidly on 'Pinkeye purplehull', but not on a resistant cultivar, 'Worthmore' pea (Vigna unguiculata). Population densities of other nematodes were not affected by cultivar of pea or the nematicide, ethoprop. Fenamiphos was more effective than ethoprop in suppressing nematode population densities. Increases in crop yield in the intensive management system ranged from 4% to 52% over untreated controls

Use of Sperm Proteins as a Putative Fertility Marker

The objectives of this study were to characterize the variation and evaluate whether CD9 and SERPINA5 could be used as fertility markers in bovine sperm

Use of Pregnancy Associated Glycoproteins to determine Fetal Age Throughout Gestation

The objective of the current study was to determine if a commercially available blood pregnancy test could be modified to detect differences in pregnancy-associated glycoprotein (PAG) concentrations that would be indicative of stage of pregnancy or fetal age

Comparison of Lateral Flow to Other Pregnancy Determination Methods in Order to Determine Accuracy of Pregnancy Status in Beef Cattle Pre and Postpartum

Study Description: Blood samples were collected from six different Bos taurus herds between day 27 and 285 of gestation (heifers n = 1,205 and cows n = 1,539). Blood samples to determine PAG clearance interval were collected weekly postpartum for up to 12 weeks (heifers n = 418 and cows n = 657). Serum was tested using the lateral flow test and were read by two technicians who were blind to pregnancy status. Level of agreement between the tests were determined by Pearson’s correlation coefficients and Kappa scores. The MIXED procedure of SAS was used to evaluate the effect of dpp and age (heifers or cows) on postpartum test results. There was a positive correlation between transrectal ultrasonography and the lateral flow test (r2 = 0.71; P \u3c 0.01), and agreement between the two tests was very good (Kappa = 0.84). Of the animals that were diagnosed nonpregnant by transrectal ultrasonography, 5.61% were called pregnant by the lateral flow test. Of the animals diagnosed pregnant by transrectal ultrasonography, 2.00% were called not pregnant by the lateral flow test. Thus, a 92.38% agreement occurred between the two methods. For postpartum samples, there was no effect (P = 0.21) of age, but there was an effect of dpp (P \u3c 0.01) and a tendency for a dpp by age interaction (P = 0.06). All animals were still considered pregnant from the previous pregnancy through 35 dpp (100 ± 2.58%). The percentage of females receiving a false positive test result further decreased with time postpartum, by 77 dpp there were 13.72 ± 3.16% of the females positive for pregnancy and at 84 dpp there were 4.11 ± 4.39% positive for pregnancy detection

Use of Pregnancy Associated Glycoproteins to Determine Fetal Age Throughout Gestation in Cattle

Objective The objective of the current study was to determine if a commercially available blood pregnancy test could be modified to detect differences in pregnancy-associated glycoprotein (PAG) concentrations to indicate stage of pregnancy or fetal age in cattle. Study Description Previously identified pregnant females were grouped by age (pre-primiparous or multiparous). Blood samples were collected between day 27 and 190 of pregnancy (n = 176 from pre-primiparous and n = 240 from multiparous) and serum was tested in duplicate using a commercially available blood pregnancy test, IDEXX Alertys Pregnancy Test. Procedures were adapted to allow concentrations to fall within the detectible range of the assay. Animals were grouped by parity (pre-primiparous vs multiparous) into 4 gestational groups (group 1 - \u3c 30 days, group 2 - 30 to 90 days, group 3 - 91 to 178 days, and group 4 - \u3e178 days). Data were analyzed using the MIXED procedure of SAS with parity and gestational age in the model. There was an effect of parity, gestational age, and a parity by gestational age interaction (P \u3c 0.01). Pre-primiparous animals had greater concentrations of PAGs compared to multiparous animals. Among pre-primiparous animals, serum PAG concentrations did not differ between gestational age groups 1, 2, or 3 (P \u3e 0.37), but group 4 had greater PAG concentrations than all other groups (P \u3c 0.01). Among multiparous animals, serum PAG concentrations decreased from group 1 to 2 (P \u3c 0.01), and then increased throughout gestation (P \u3c 0.01). Data were then analyzed using the REG procedure in SAS within gestational age group. There was a positive correlation between gestational age and PAG concentrations among both pre-primiparous (P \u3c 0.01; R2 = 0.25) and multiparous (gestational age 30 and greater P \u3c 0.01; R2 = 0.64)

Use of Pregnancy Associated Glycoproteins to Determine Fetal Age Throughout Gestation and Clearance Rate in Postpartum Beef Cattle

Study Description: Previously identified pregnant females from four different herds and postpartum females from one herd were utilized. Blood samples were collected (n = 1,753; study 1) between d 28 and 285 of gestation and (heifers n = 418 and cows n = 657; study 2) once a week for up to 12 weeks after calving. Serum was tested in duplicate using a commercially available blood pregnancy test, IDEXX Alertys Pregnancy Test. In study 1, procedures were modified to allow PAG concentrations to fall within the detectible range of the assay. Data were analyzed using the MIXED procedure of SAS with cow age and gestational age (also divided into four gestational age groups: 1) \u3c 30 d; 2) 30-90 d; 3) 91-180 d; 4) \u3e 180 d) in the model and then analyzed further using the REG procedure in SAS within gestational age group. In study 2, data were analyzed as repeated measure using the MIXED procedure of SAS with cow age, days postpartum (dpp), and cow age by dpp in the model, then data were analyzed further using the REG procedure in SAS. In study 1, there was a significant effect of gestational age and cow age by gestational age interaction (P \u3c 0.01) as well as a tendency of cow age (P = 0.08). Among heifers and cows, serum PAG concentrations did not differ between gestational age groups 1 and 2 (P \u3e 0.84), however, PAG concentrations differed between groups 2 and 3 (P \u3c 0.0001) and 3 and 4 (P \u3c 0.0001). There was a positive correlation between gestational age and PAG concentrations (P \u3c 0.01; r2 = 0.2604). In study 2, there was a significant effect of days postpartum (dpp; P \u3c 0.01) on PAG concentrations; however, PAG concentrations were not influenced by cow age (P = 0.73) or cow age by dpp (P = 0.55). Concentrations of PAGs rapidly decreased from d 0 to 50 postpartum and then continued to gradually decrease (P \u3c 0.01; r2 = 0.8083). Prior to 42 dpp, PAG concentrations were sufficiently elevated which resulted in false positive readings

Relationship of DAG1 and SERPINA5 Sperm Proteins With Bull Fertility

Study Description: Semen from 22 dairy bulls was used to evaluate the presence, localization, and quantification of DAG1 and SERPINA5 on sperm. Sperm motility parameters and viability was also evaluated for semen from each bull. Semen from 19 out of the 22 dairy bulls was used for in vitro embryo production (two Low-SCR and one High-SCR were not available for in vitro embryo production). Bulls were classified based on their sire conception rates (SCR) values as High-SCR (SCR \u3e 1.0) or Low-SCR fertility (SCR \u3c -4.0). Low fertility bulls were subdivided based on their blastocyst rate (BL) as High-BL (Low-SCR/High-BL BL ≥ 31%) or Low-BL (Low-SCR/Low-BL BL ≤ 26%), and High-SCR bulls were not subdivided. The GLM procedure in SAS was used with bull as a fixed effect to determine if variance was greater between bulls compared to within bull. Correlations were determined among DAG1 and SERPINA5 concentrations, percentage of tail labeled for SERPINA5, SCR, sperm total motility, progressive motility, and viability, and in vitro embryo produced cleavage rate (CL) and BL. The GLIMMIX procedure of SAS was used to evaluate the relationship of bull field fertility (High- and Low-SCR), and field and in vitro fertility (High-SCR, Low-SCR/High-BL, Low-SCR/Low-BL) classifications with sperm total (TMOT) and progressive (PROG) motility, viability, CL, BL, DAG1 and SERPINA5 relative concentration, and proportion of sperm tail labeled for SERPINA5. Both SERPINA5 and DAG1 were localized on the sperm head; however, SERPINA5 was also localized on the sperm tail. There was greater variance in concentration among bulls compared to within bull for both DAG1 (P \u3c 0.01; 69.4 vs 49.1, respectively) and SERPINA5 (P \u3c 0.01; 325.8 vs 285.4, respectively). There was a positive correlation between concentration of DAG1 and SERPINA5 (P = 0.01; r = 0.54). Concentrations of SERPINA5 were also correlated with CL (P = 0.04; r = 0.48), and percentage of sperm tail labeled for SERPINA5 was correlated with viability (P = 0.05; r = 0.44) and tended to be correlated with CL (P = 0.10; r = 0.39). There was no relationship between SCR or BL rate classifications and DAG1 (P ≥ 0.66), SERPINA5 (P ≥ 0.54), or percentage of sperm tail labeled for SERPINA5 (P ≥ 0.48)