Tall fescue forage mass in a grass-legume mixture: predicted efficiency of indirect selection     

Blair L. Waldron  Michael D. Peel  Steven R. Larson  Ivan W. Mott  J. Earl Creech 《Euphytica》2017,213(3):67

High fertilizer prices and improved environmental stewardship have increased interest in grass-legume mixed pastures. It has been hypothesized, but not validated, that the ecological combining ability between grasses and legumes can be improved by breeding specifically for mixture performance. This experiment examined the predicted efficiency of selection in a grass monoculture environment to indirectly improve tall fescue (Lolium arundinaceum (Schreb.) Darbysh.) forage mass in a grass-legume mixture. Heritability, genetic and rank correlations, and selection efficiencies were estimated for forage mass in a tall fescue half-sib population grown as spaced-plants overseeded with either turf-type tall fescue (monoculture) or alfalfa (mixture). Heritability for tall fescue forage mass in monoculture ranged from 0.32 to 0.70 and were always similar or greater than those in mixture (range 0.27–0.55) for four successive harvests and annual total. Genetic correlations between monoculture and mixture tall fescue forage mass varied with values of 0.48, 0.92, ?0.31, 0.70, and 0.25 in June, July, August, October, and annual total, respectively. Indirect selection efficiencies exceeded or approached direct selection for mixtures only in July and October (1.29, and 0.73, respectively). Whereas, indirect selection efficiencies were low in June, August, and annual forage mass (0.58, ?0.31, and 0.28, respectively). Moreover, low Spearman’s rank correlations (?0.03 to 0.35) indicated differing half-sib family performance between the monoculture and mixture environments. Results indicate that direct selection should be used to improve tall fescue forage mass in a grass-legume mixture, and support the hypothesis of increasing ecological combining ability by breeding for mixtures per se.  相似文献   

The sounds of silence: regime shifts impoverish marine soundscapes     

Tullio Rossi  Sean D. Connell  Ivan Nagelkerken 《Landscape Ecology》2017,32(2):239-248

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Chemical and nutritional characteristics of Cannabis sativa L. co-products     

Alessandro Vastolo  Serena Calabrò  Severina Pacifico  Bossima Ivan Koura  Monica Isabella Cutrignelli 《Journal of animal physiology and animal nutrition》2021,105(Z1):1-9

Cannabis sativa L. is an annual herbaceous plant. It was used for centuries to obtain different products. In the last century, hemp cultivation was forbidden due to the psychoactive effects of tetrahydrocannabinol acid (THCA). In the last years, new strains, characterized by high cannabidiolic acid (CBDA) and low THCA level, were developed renewing the interest in hemp cultivation to obtain food or to extract essential oils from flowers. All these processes produce many residues with different chemical–physical characteristics. In order to evaluate their potential use also in animal nutrition, some hemp co-products were evaluated. Two different co-products of seed processes (flour and oil) and two co-products obtained trimming the flowers, differing in granulometry were used. The samples were analysed for chemical composition and evaluated in vitro using the gas production technique with buffaloes' ruminal inoculum. All hemp co-products showed interesting nutritional characteristics, such as crude protein content always higher than 20% on a dry matter basis, and high neutral detergent fibre concentration partially lignified. The in vitro gas production parameters at 120 h of incubation showed quite low fermentability testified by the low organic matter degradability and cumulative gas volume (OMD from 28.09 to 45.64% and OMCV from 110 to 164 ml/g, respectively). Also, the methane produced after 24 h of incubation was particularly low (from 1.78 to 11.73 ml/g dOM). These results could be due to the high lipid and ash amounts or to the CBDA content that probably affected the CH₄ formation processes. According to preliminary results obtained by this study, it is possible to hypothesize that these co-products could be useful to mitigate the methane production into the rumen. Further studies are necessary in order to evaluate the correct inclusion into the diet for ruminants.  相似文献   

Use of an epidural catheter inserted at L1–L2 in a dog undergoing pelvic limb amputation          下载免费PDF全文

Mathieu Raillard  Thomas R Harcourt‐Brown  Ivan P Doran  Paul D MacFarlane 《Veterinary anaesthesia and analgesia》2016,43(2):237-238

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Seasonal turnover and insights into the overwintering biology of wireworms (Coleoptera: Elateridae) in the Canadian Prairies     

Ivan Drahun  Elise A. Poole  Katherine A. Hunt  Willem G. van Herk  Christophe M. LeMoine  Bryan J. Cassone 《Pest management science》2023,79(2):526-536

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Assessment of the socio-economic impacts associated with the arrival of apple snail (Pomacea canaliculata) in Mwea irrigation scheme,Kenya     

Kate L. Constantine  Fernadis Makale  Idah Mugambi  Duncan Chacha  Harrison Rware  Alexander Muvea  Vincent K. Kipngetich  Justice Tambo  Adewale Ogunmodede  Djami Djeddour  Corin F. Pratt  Ivan Rwomushana  Frances Williams 《Pest management science》2023,79(11):4343-4356

Background

In Kenya, rice (Oryza sativa L.) is mainly produced under irrigation by small-scale farmers. Mwea irrigation scheme (MIS) in Kirinyaga County accounts for 80–88% of rice production. Here, rice is the main source of livelihood and a source of revenue generation for the county. However, a recently established invasive freshwater snail, Pomacea canaliculata (Lamarck) (family: Ampullariidae), a species of apple snail, presents a serious threat to rice production.

Results

Household surveys, focus group discussions and key informant interviews highlight apple snail as a serious problem in MIS. Households that observed at least a moderate level of infestation (>20% of cultivated area) experienced significant reductions in rice yield (~14%) and net rice income (~60%). Farmers reported increased use of chemical pesticides for management of apple snail. In addition, the cost of hired labor for physical removal of egg masses and snails is resulting in substantial negative effects on net income. Farmer age, area of land owned, responsibility for decision-making, receipt of extension advice, training, and membership of a farmer organization, were all statistically significant variables to explain farmers awareness of the need for area-wide apple snail management.

Conclusion

Strategies to limit the spread of apple snail are urgently needed. A Multi-Institutional Technical Team (MITT) has been established to spearhead management efforts and consolidate advice to farmers on how to manage apple snail. However, without action to mitigate spread, the consequences could be disastrous for rice production and food security in Kenya, and for other rice growing regions across Africa. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.  相似文献   

Selection of compounds acting as aphid development and reproduction regulators: Laboratory screening     

Jelena Kuldova  Ivan Hrdy  Zden Wimmer 《Pest management science》1994,41(4):319-325

Newly synthesized compounds were examined in screening tests with the pea aphid, Acyrthosiphon pisum (Harris) for juvenilizing effects. usign the spray-residue method. Two derivatives of 2-(4-hydroxvbenzyl)eyclohexanone bearing a carbamate or an ether group were found to be the most active inhibitors of development and reproduction. Tests with the hop aphid, Phorodon humuli (Schrank) of insecticide-susceptible and multi-resistant biotypes and with the green peach aphid, Myzus persicae (Sulzer) confirmed their biological activity. Cross-resistance between conventional insecticides and juvenoids was not indicated. The formation of supernumerary larvae, where retention of larval cauda and corresponding larval characters were observed and reproduction was entirely suppressed, was recognized as the critical result of the juvenilizing effect. The production of viable progeny was not affected in those aphids which survived treatment and developed normal adult external genitalia.  相似文献   

Evaluation of PCR,IEF and ELISA techniques for the detection and identification of potato cyst nematodes from field soil samples in England and Wales     

Said K Ibrahim  Stephen T Minnis  Anthony D P Barker  Mike D Russell  Patrick P J Haydock  Kenneth Evans  Ivan G Grove  Simon R Woods  Andrew Wilcox 《Pest management science》2001,57(11):1068-1074

Effective management of potato cyst nematodes (PCNs) requires simple, rapid and accurate identification and quantification of field populations. Soil samples from a survey of 484 fields in potato rotations in England and Wales were used to compare the identification and quantification of PCNs using IEF, PCR, ELISA and bait plant tests. The cyst counts and bait plant test revealed that 64.3% of field samples contained PCNs. Bait plant tests increased the detection rate of PCNs in field samples by 4–6.4%. This means that some infestations are cryptic and would not normally be detected by standard counts. IEF, PCR and ELISA methods distinguished between Globodera rostochiensis and G pallida and were able to register mixed populations; however they were not in full agreement. All methods suggested that G pallida is the dominant species in the field samples tested. The PCR results indicated that 66% of field samples contained pure G pallida, 8% contained pure G rostochiensis and 26% contained mixtures of the two species. Estimates of the relative process times taken per sample in the PCR, IEF and ELISA techniques are given. © 2001 Society of Chemical Industry  相似文献   

New data on Myxobolus longisporus (Myxozoa: Myxobolidae), a gill infecting parasite of carp, Cyprinus carpio haematopterus, from Chinese lakes     

Dyková I  Fiala I  Nie P 《Folia parasitologica》2003,50(4):263-268

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Risk factors for stillbirths in two swine farms in the south of Brazil     

Lucia T  Corrêa MN  Deschamps JC  Bianchi I  Donin MA  Machado AC  Meincke W  Matheus JE 《Preventive veterinary medicine》2002,53(4):57-292

We evaluated stillbirth risk factors in two commercial swine farms of the Rio Grande do Sul State (south of Brazil). The study was conducted during 1 month in Farm A and during 2 months in Farm B, both during 1999. Data for all farrowings that occurred during the study period were recorded (101 for Farm A and 373 for Farm B), without interference in the farm management. In Farm A, 39% of all litters born during the period of interest had stillborn piglets and the stillborn risk for piglets was 12%. In Farm B, 25% of all litters had stillborn piglets whereas the stillborn risk was 2%. Variables considered as potential risk factors for stillbirths were: parity (1, 2–3, 4+); breed (purebred or crossbred); sow body-condition (normal or fat); use of oxytocin during parturition (yes or no); obstetric intervention through vaginal palpation (yes or no); farrowing duration (<4 or ≥4 h); mummified fetuses (yes or no); total litter size (<12 or ≥12 piglets); and litter birth weight (<11 or ≥11 kg). All stillborn piglets had their classification validated by necropsy. In multivariable logistic-regressions, the cases were the litters having at least one stillborn piglet. In Farm A, litters having at least 12 pigs and in which oxytocin was used during the parturition had 20.8-times-higher odds of stillborn occurrence. In Farm B, litters from sows having parity ≥4 had 2.2-times-higher odds of stillborn occurrence than litters from parity 2 to 3 females, litters having ≥12 pigs had 2.0-times-higher odds of a stillborn piglet than smaller litters and farrowings in which vaginal palpation was performed had 8.0-times-higher odds. Farrowing room management to minimize stillborn risk should target higher-parity females, large litters and optimization of practices of obstetric interventions.  相似文献