Benzimidazole-resistant beta-tubulin alleles in a population of parasitic nematodes (Cooperia oncophora) of cattle   总被引：1，自引：0，他引：1  

Winterrowd CA  Pomroy WE  Sangster NC  Johnson SS  Geary TG 《Veterinary parasitology》2003,117(3):161-172

Three anthelmintic classes with distinct mechanisms of action are commercially available. Selection of nematode populations resistant to all these drugs has occurred, particularly in trichostrongyloid parasites of sheep. Anthelmintic resistance in cattle parasites has only recently been recognized and appears to be less pronounced, even though very similar species infect both hosts. To understand the bases for differences in the rate of resistance development in sheep versus cattle parasites, it is important to first demonstrate that the same kinds of resistance alleles exist in both. The benzimidazoles (BZ), which have been used for more than 40 years, were chosen as an example. BZ-sensitive (BZ(S)) and BZ-resistant (BZ(R)) nematodes that parasitize sheep have been distinguished at the molecular level by a single nucleotide change in the codon for amino acid 200 of a beta-tubulin gene, a switch from TTC (phenylalanine) to TAC (tyrosine). PCR primers were designed to completely conserved regions of trichostrongyloid beta-tubulin genes and were used to amplify DNA fragments from Haemonchus contortus (cDNA from a BZ(S) and a BZ(R) library) as positive controls. The technique was then extended to the cattle parasites, Cooperia oncophora and Ostertagia ostertagi (from genomic DNA). Sequence analysis proved the presence of amplified BZ(S) alleles in all three species and BZ(R) alleles in the BZ(R) population of H. contortus. Based on these data, nested PCR primers using the diagnostic T or A as the most 3' nucleotide were designed for each species. Conditions for selective PCR were determined. To demonstrate feasibility, genomic DNA was recovered from individual H. contortus L(3) larvae from both BZ(S) and BZ(R) populations. Genomic DNA was also isolated from >70 individual adult male C. oncophora collected from a cattle farm in New Zealand with reported BZ resistance. Allele-specific PCR discriminated among heterozygotes and homozygotes in both species. This method could find utility in studying the molecular epidemiology of BZ resistance in cattle parasites and for defining the variables that limit the development and spread of anthelmintic resistance in this host.  相似文献   

Effect of ovulatory follicle size and expression of estrus on progesterone secretion in beef cows     

Busch DC  Atkins JA  Bader JF  Schafer DJ  Patterson DJ  Geary TW  Smith MF 《Journal of animal science》2008,86(3):553-563

Induced ovulation of small dominant follicles (SF, < 12 mm; CO-Synch protocol) in postpartum beef cows resulted in formation of corpora lutea (CL) that exhibited a delayed rise in progesterone (P4) compared with CL from large dominant follicles (LF, > 12 mm). Experiment 1 characterized P4 concentrations from ovulation to subsequent estrus among GnRH-induced or spontaneously ovulated SF (or= 12 mm) to determine if P4 secretion by CL formed from GnRH-induced SF remains lower postovulation in nonlactating beef cows. Nonlactating beef cows were induced to ovulate 48 h after PGF(2alpha) (CO-Synch; GnRH on d - 9, PGF(2alpha) on d - 2, and GnRH on d 0) or exhibited estrus and spontaneously ovulated after PGF(2alpha). Follicle size was measured at the second GnRH in cows induced to ovulate or approximately 3 h after the onset of estrus for cows that ovulated spontaneously. Cows were classified into 1 of 4 groups: 1) GnRH-induced ovulation-SF (or= 12 mm; Ind-LF; n = 16); 3) spontaneous ovulation-SF (or= 12 mm; Spon-LF; n = 22). Serum concentrations of P4 from d 3 to 15 were reduced in the Ind-SF compared with the Ind-LF (P = 0.05), Spon-SF (P = 0.07), and Spon-LF (P = 0.03). Experiment 2 characterized P4 concentrations (0 to 60 d postAI) among GnRH-induced or spontaneously ovulated SF (or= 13 mm) to determine if P4 secretion by CL formed from GnRH-induced SF remained lower during early gestation. Ovulation was induced with GnRH 48 h after PGF(2) (CO-Synch) or occurred spontaneously, and ovulatory follicle size was measured at AI. Lactating cows were classified into 1 of 3 groups: 1) GnRH-induced ovulation-SF (or= 13 mm; Ind-LF; n = 43); or 3) spontaneous ovulation-LF (>or= 13 mm; Spon-LF; n = 27). The increase in P4 concentrations was greater (P = 0.06) in pregnant (d 2 to 12) compared with nonpregnant cows. Also, the increase in P4 from d 2 to 12 was greater (P = 0.01) in the Ind-LF compared with the Ind-SF groups, but there was no difference (P = 0.94) among groups in P4 from d 14 to 60 in pregnant cows. Follicle size at AI influenced the increase in P4 in cows that failed to conceive (P = 0.007), but not among cows that became pregnant (P = 0.32) to AI. In summary, P4 secretion after GnRH-induced ovulation of SF was decreased from d 2 to 12 compared with that of LF, but was similar among pregnant cows from d 14 to 60 postAI (d 0).  相似文献   

Atlanto Axial Subluxation in the Canine   总被引：2，自引：0，他引：2  

J. G. Geary  J. E. Oliver†  B. F. Hoerlein‡ 《The Journal of small animal practice》1967,8(10):577-582

Abstract— A slowly progressive subluxation of the atlanto-axial articulation has been seen in ten dogs of various small breeds. Lateral radiographs show the obvious vertebral displacement and clearly confirm the diagnosis. Surgical repair has been accomplished by wiring the atlas to the axis in the last three dogs.
Résumé— Une subluxation progressive, lente de l'articulation atlantoaxiale a été trouvée dans 10 chiens de races variées, tous de type "petit-chien". Des radiographies latérales montrent un déplace-ment vertébral évident et confirment clairement le diagnostique. L'intervention chirurgicale a été accomplice par fixation par fils métalliques de l'atlas à l'axis, chez les 3 derniers chiens.
Zusanunenfassnng—Eine langsam fortschreitende Subluxation des Atlas-Epistropheus- Gelenkes wurde bei 10 kleinrassigen Hunden beobachtet. Seitliche Röntgenaufnahmen zeigen die offen-sichtliche vertebrale Verlagerung und bestätigen einwandfrei die Diagnosis. Chirurgische Behand-lung bei den letzten drei Hunden war erfolgreich, indem der Atlas mit Draht in der richtigen Stellung an den Epistropheus befestigt wurde.  相似文献   

Interrelationships among physicochemical properties, absorption and anthelmintic activities of 2-desoxoparaherquamide and selected analogs     

Johnson SS  Coscarelli EM  Davis JP  Zaya RM  Day JS  Barsuhn CL  Martin RA  Vidmar TJ  Lee BH  Conder GA  Geary TG  Ho NF  Thompson DP 《Journal of veterinary pharmacology and therapeutics》2004,27(3):169-181

The interrelationships between physicochemical properties, absorption and potency of 2-desoxoparaherquamide and five analogs, representing a new anthelmintic class, were evaluated in in vitro and in vivo assays. At pH 7.5, rates of drug absorption by the gastrointestinal nematode Haemonchus contortus and jird small intestine, parameterized by the permeability coefficient, P(e), ranged from 1.2-2.4 x 10(-4) cm/min (nematode) to 2.5-5.5 x 10(-3) cm/min (jird). In the jird intestine, absorption was pH-dependent, with P(e) at pH 7.5 being twice that at pH 4.5, reflecting the negative influence of protonation on transport of these weakly basic molecules. Each compound rapidly paralyzed H. contortus during in vitro exposure to therapeutically relevant concentrations (1-10 microm). The kinetics of drug action on motility in vivo mirrored their in vitro effects; motility concentrations were reduced in nematodes collected from jird stomach 3 h following oral drug dosing, by which time > or =50% clearance of the parasites had occurred. The nematode/medium partition coefficient K ranged from 10.1 to 16.1, consistent with the lipophilic nature of the compounds. The time required to reduce motility in vitro by 50% (t50*) and P(e) were used to determine C(n)*, the concentration of drug in the nematode at t50*, as an indicator of intrinsic potency. In the jird, the apparent potencies of the compounds were insensitive to route of administration (i.e. oral = i.v. = i.p. = i.m.) for H. contortus and two other gastrointestinal nematodes, Ostertagia ostertagi and Trichostrongylus colubriformis; topical administration, however, required three to 10-fold higher doses for equivalent efficacy.  相似文献   

Synchronization of ovulation using GnRH or hCG with the CO-Synch protocol in suckled beef cows.   总被引：2，自引：0，他引：2  

T W Geary  R R Salverson  J C Whittier 《Journal of animal science》2001,79(10):2536-2541

The objectives of this study were to evaluate replacing GnRH with hCG and the effects of 48-h calf removal (CR) on pregnancy rates of cows synchronized with the CO-Synch protocol. Suckled beef cows (n = 467) at two locations were assigned to treatment by breed, age, and calving date. Treatment included either GnRH with (n = 121) or without CR (n = 117) or hCG with (n = 115) or without CR (n = 114) using the CO-Synch protocol. On d 0 and 9, cows received either hCG (2,500 IU, i.m.) or GnRH (100 microg, i.m.), and on d 7 all cows received PGF2alpha (25 mg). At one location, blood samples were collected from all cows (n = 203) on d -14, -7, 0, 7, 9, and 16. Calves were removed on d 7 and returned on d 9 (48 h) from approximately half of the cows that received GnRH or hCG. Cows that were detected in estrus between d 6 and 9 were bred approximately 12 h later and received no further injections. Cows not observed in estrus by d 9 received a second injection of either GnRH or hCG and were timed-inseminated. The AI pregnancy rates for GnRH-treated cows with or without CR and hCG-treated cows with or without CR were 46, 49, 35, and 34%, respectively (P = 0.44). Pregnancy rates of cows differed by treatment x age interaction (P = 0.07), hormone (P = 0.09), and hormone x age (P = 0.01) but not by CR (P = 0.66) or CR x age (P = 0.33). Among 2-yr-olds, pregnancy rates were higher for cows treated with hCG without CR than for cows that received GnRH with calf removal, whereas cows treated with hCG with CR and GnRH without CR were intermediate. In addition hCG-treated 2-yr-olds had higher pregnancy rates than GnRH-treated 2-yr-olds regardless of calf presence, but the reverse was true for older cows. Overall, GnRH-treated cows (48%) had a higher (P = 0.09) pregnancy rate than hCG-treated cows (34%). Among anestrous cows, GnRH and hCG were similar (P = 0.40) in their ability to induce ovulation and corpus luteum formation after the first and second injections of GnRH (31 and 76%, respectively) or hCG (39 and 61%, respectively). More (P = 0.001) hCG-treated cows exhibited short estrous cycles following timed AI. We conclude that hCG is not a suitable replacement for GnRH to synchronize ovulation with the CO-Synch protocol in multiparous cows, although further evaluation among primiparous cows is warranted using hCG with the CO-Synch protocol.  相似文献   

Effects of restricted feeding of beef heifers during the postweaning period on growth, efficiency, and ultrasound carcass characteristics     

Roberts AJ  Paisley SI  Geary TW  Grings EE  Waterman RC  MacNeil MD 《Journal of animal science》2007,85(10):2740-2745

Traits used for identification of replacement beef heifers and feeding levels provided during postweaning development may have major financial implications due to effects on maintenance requirements and level of lifetime production. The current study evaluated the effects of 2 levels of feeding during the postweaning period on growth, G:F, and ultrasound carcass measurements of heifers, and the associations among these traits. Heifers (1/2 Red Angus, 1/4 Charolais, and 1/4 Tarentaise) born in 3 yr were randomly assigned to a control (fed to appetite; n = 205) or restricted (fed at 80% of that consumed by controls adjusted to a common BW basis; n = 192) feeding during a 140-d postweaning period. Heifers were individually fed a diet of 68% corn silage, 18% alfalfa, and protein-mineral supplement (DM basis) in pens equipped with Calan gates. Ultrasound measurements of LM area, intramuscular fat, and subcutaneous fat thickness over the LM were made on d 140 (382 +/- 0.8 d of age). Average daily DMI was 4.1 and 5.6 kg/d for restricted and control heifers, respectively (P < 0.001). Feed restriction decreased (P < 0.001) BW (292 vs. 314 kg), ADG (0.52 vs. 0.65 kg/d), LM area (55 vs. 59 cm2), intramuscular fat (3.2 vs. 3.5%), and subcutaneous fat thickness over the LM (3.2 vs. 3.9 mm), but increased G:F (0.12 vs. 0.11) when compared with control at the end of the 140-d study. The magnitude of the associations of DMI with ADG (r = 0.32 vs. 0.21), 140-d BW (r = 0.78 vs. 0.36), hip height (r = 0.57 vs. 0.17), LMA (r = 0.30 vs. 0.18), and BCS (r = 0.17 vs. 0.11) was greater in restricted- than control-fed heifers. Variance of residual feed intake, calculated within each treatment, was greater (P < 0.01) in control (0.088) than restricted (0.004) heifers, and magnitude of association between residual feed intake and average DMI was greater in control (r = 0.88) than restricted (r = 0.41) heifers. Pregnancy rate tended (P = 0.11) to be reduced in heifers that had been developed on restricted feeding (86.3 +/- 2.3 vs. 91.5 +/- 2.3%). However, ADG was greater (P < 0.001) in restricted than control heifers (0.51 vs. 0.46 kg/d) while grazing native range in the 7 mo after restriction. In summary, restricted heifers consumed 22% less feed on a per-pregnant-heifer basis during the development period and had a greater magnitude of association between DMI and several growth-related traits at the end of the 140-d postweaning feeding period, which is indicative of improved efficiency.  相似文献   

Does Fusarium‐caused seed mortality contribute to Bromus tectorum stand failure in the Great Basin?     

S E Meyer  J‐L Franke  O W Baughman  J Beckstead  B Geary 《Weed Research》2014,54(5):511-519

Bromus tectorum (cheatgrass, downy brome) is an important invader in western North America, dominating millions of hectares of former semi‐arid shrubland. Stand failure or ‘die‐off’ is relatively common in monocultures of this annual grass. The study reported here investigated whether soil‐borne pathogens could be causal agents in die‐offs. Soils from two die‐off areas and adjacent B. tectorum stands were used in a glasshouse experiment with sterilised and non‐sterilised treatments. Soil sterilisation did not increase emergence, which averaged 80% in both die‐off and non‐die‐off soils. Seedling biomass was higher in die‐off soils, probably due to increased nitrogen availability. Fusarium was isolated from 80% of killed seeds in non‐sterilised soil treatments. In pathogenicity tests with 16 Fusarium isolates, host seeds incubated under water stress (?1.5MPa for 1 week prior to transfer to free water) suffered over twice the mortality of seeds incubated directly in free water (25–83% with water stress vs. 5–43% without water stress). These results suggest that soil‐borne Fusarium could play a role in B. tectorum stand failure in the field, but that low water stress conditions in the glasshouse experiment were not conducive to high levels of disease. Pathogenic Fusarium isolates were obtained from seeds planted in both die‐off and non‐die‐off soils, suggesting that microenvironmental factors that affect levels of water stress might be as important as relative abundance of soil‐borne pathogens in mediating spatial patterns of disease incidence in the field.  相似文献   

Potato Black Dot – The Elusive Pathogen,Disease Development and Management     

Dennis?A.?Johnson  Brad?Geary  Leah? Tsror 《American Journal of Potato Research》2018,95(4):340-350

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Erratum to: Influence of Location,Year, Potato Rotation,and Chemical Seed Treatment on Incidence and Severity of Silver Scurf on Progeny Tubers     

Jeffrey S. Miller  Philip B. Hamm  Jeremiah K. S. Dung  Brad D. Geary  Steven R. James  Dennis A. Johnson  Kenneth Rykbost 《American Journal of Potato Research》2015,92(6):709-709

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Treatment and prognostic factors in lymphoma in cats: 103 cases (1977-1981)     

S C Mooney  A A Hayes  E G MacEwen  R E Matus  A Geary  B A Shurgot 《Journal of the American Veterinary Medical Association》1989,194(5):696-702

The records of 103 cats with lymphoma that underwent chemotherapy were reviewed. Diagnosis was confirmed by cytologic or histopathologic examination of appropriate tissue specimens. Sixty-four cats (62%) had a complete response to chemotherapy (median survival time, 7 months); 21 cats (20%) had a partial response (median survival time, 2.5 months); and 18 cats had a minimal response (median survival time, 1.5 months). Seventy-seven cats (75%) died of recurrent or progressive lymphoma, 9 cats died of feline leukemia-related anemia, 13 cats died of unrelated causes, and 4 cats were alive. Stage of disease was significantly (P = 0.009) related to response to treatment, and stage of disease and FeLV status were both significantly (P = 0.002 and P less than 0.001, respectively) related to survival.  相似文献