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Prevalence of internal parasites in beef cows in the United States: Results of the National Animal Health Monitoring System’s (NAHMS) beef study, 2007‐2008
2015
Stromberg, Bert E. | Gasbarre, Louis C. | Ballweber, Lora R. | Dargatz, David A. | Rodriguez, Judith M. | Kopral, Christine A. | Zarlenga, Dante S.
During the United States Department of Agriculture (USDA) National Animal Health Monitoring System’s (NAHMS) 2007‐2008 beef study, 567 producers from 24 US States were offered the opportunity to collect fecal samples from weaned beef calves and have them evaluated for the presence of parasite eggs (Phase 1). Participating producers were provided with instructions and materials for sample collection. Up to 20 fresh fecal samples were collected from each of the 99 participating operations. Fresh fecal samples were submitted to one of 3 randomly assigned laboratories for evaluation. Upon arrival at the laboratories, all samples were processed for the enumeration of strongyle, Nematodirus, and Trichuris eggs using the modified Wisconsin technique. The presence or absence of coccidian oocysts and tapeworm eggs was also noted. In submissions where the strongyle eggs per gram exceeded 30, aliquots from 2 to 6 animals were pooled for DNA extraction. Extracted DNA was subjected to genus level polymerase chain reaction (PCR) identification for the presence of Ostertagia, Cooperia, Haemonchus, Oesophagostomum, and Trichostrongylus. In this study, 85.6% of the samples had strongyle type, Nematodirus, and Trichuris eggs. Among the samples evaluated, 91% had Cooperia, 79% Ostertagia, 53% Haemonchus, 38% Oesophagostomum, 18% Nematodirus, 7% Trichuris, and 3% Trichostrongylus. The prevalence of coccidia and tapeworm eggs was 59.9% and 13.7%, respectively.
Afficher plus [+] Moins [-]Effectiveness of current anthelmintic treatment programs on reducing fecal egg counts in United States cow-calf operations
2015
Gasbarre, Louis C. | Ballweber, Lora R. | Stromberg, Bert E. | Dargatz, David A. | Rodriguez, Judy M. | Kopral, Christine A. | Zarlenga, Dante S.
During the United States Department of Agriculture (USDA) National Animal Health Monitoring System’s (NAHMS) 2007‐2008 beef study, producers from 24 states were offered the opportunity to evaluate their animals for internal parasites and for overall responses to treatment with anthelmintics. A lapse of 45 d was required between initial sampling and any previous treatments. Choice of anthelmintic (oral benzimidazoles, and both injectable and pour-on endectocides) was at the discretion of the producer so as not to alter the local control programs. Fresh fecal samples were collected from 20 animals, or from the entire group if less than 20, then randomly assigned to 1 of 3 participating laboratories for examination. Analyses consisted of double centrifugation flotation followed by enumeration of strongyle, Nematodirus, and Trichuris eggs (the presence of coccidian oocysts and tapeworm eggs was also noted). Where strongyle eggs per gram (epg) exceeded 30, aliquots from 2 to 6 animals were pooled for egg isolation and polymerase chain reaction (PCR) analysis for the presence of Ostertagia, Cooperia, Haemonchus, Oesophagostomum, and Trichostrongylus. Results from 72 producers (19 States) indicated that fecal egg count reductions were < 90% in 1/3 of the operations. All operations exhibiting less than a 90% reduction had used pour-on macrocyclic lactones as the anthelmintic treatment. While some of these less than expected reductions could have been the result of improper drug application, PCR analyses of the parasite populations surviving treatment, coupled with follow-up studies at a limited number of sites, indicated that less than expected reductions were most likely due to anthelmintic resistance in Cooperia spp. and possibly Haemonchus spp.
Afficher plus [+] Moins [-]The follicle characteristic and immature oocyte quality obtained from repeated transvaginal oocyte retrieval in Bos indicus beef cows
2015
Izuan Bahtiar A. J. | Ahmad J. | Saadiah J. | Azizah A. | Ahmad Nazri A. R.
The development and availability of follicles is an indicator to predict which of the follicle sizes are suitable to recover the oocytes assisted by means of ultrasonography of transvaginal oocyte retrieval (OPU). Thus, the study was done in order to characterize the follicular recruitment and distribution in response to the repeated removal of follicles, and thus to determine the availability of follicles and immature oocytes harvested repeatedlyfor two consecutive days of OPU in beef cows. Results indicated that 24-h OPU showed significantly greater numbers of medium and large follicles than small categories (P<0.05). However the 48-hr of OPU does not showed any differences of follicles categories (P>0.05). The mean total number of follicles and immature oocytes recovered were higher (P<0.05) in 24-hr OPU (13.76±1.2 and 7.38 ± 1.7) compared to 48-hr OPU (9.08 ± 1.5 and 3.54 ± 1.00) with the oocyte retrieval rate of 51.22% and 38.17%, respectively. The morphological classification indicated the 24-hr oocyte retrieval produced 62% of suitable immature oocytes that can be used for in vitro embryo production. In conclusion, the repeated removal of two consecutive days of OPU has averted the development of dominant follicle, and thus, gave an atmosphere to the subordinate follicles to continue growth relatively to an equal proportion of small, medium and large categories of follicles. Due to the reduction of follicle and recovery rate at 48-hr it is suggested that OPU be carried out later than 48 hour so that the follicle has more time to increase the diameter size.
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