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PubMed2003

Agricultural management practices to sustain crop yields and improve soil and environmental qualities.

In the past several decades, agricultural management practices consisting of intensive tillage and high rate of fertilization to improve crop yields have resulted in the degradation of soil and environmental qualities by increasing erosion and nutrient leaching in the groundwater and releasing greenhouses gases, such as carbon dioxide (CO2) and nitrous oxide (N2O), that cause global warming in the atmosphere by oxidation of soil organic matter. Consequently, management practices that sustain crop yields and improve soil and environmental qualities are needed. This paper reviews the findings of the effects of tillage practices, cover crops, and nitrogen (N) fertilization rates on crop yields, soil organic carbon (C) and N concentrations, and nitrate (NO3)-N leaching from the soil. Studies indicate that conservation tillage, such as no-till or reduced till, can increase soil organic C and N concentrations at 0- to 20-cm depth by as much as 7-17% in 8 years compared with conventional tillage without significantly altering crop yields. Similarly, cover cropping and 80-180 kg N ha(-1) year(-1) fertilization can increase soil organic C and N concentrations by as much as 4-12% compared with no cover cropping or N fertilization by increasing plant biomass and amount of C and N inputs to the soil. Reduced till, cover cropping, and decreased rate of N fertilization can reduce soil N leaching compared with conventional till, no cover cropping, and full rate of N fertilization. Management practices consisting of combinations of conservation tillage, mixture of legume and nonlegume cover crops, and reduced rate of N fertilization have the potentials for sustaining crop yields, increasing soil C and N storage, and reducing soil N leaching, thereby helping to improve soil and water qualities. Economical and social analyses of such practices are needed to find whether they are cost effective and acceptable to the farmers.

Agriculture↗
PubMed2002

Forage intake, meal patterns, and milk production of lactating dairy cows fed grass silage or pea-wheat bi-crop silages.

This study investigated the feed intake, milk production, and plasma nutrient status in dairy cows fed inter-cropped pea-wheat (bi-crop) silages comprised of contrasting ratios of pea to wheat. Spring peas (cv. Magnus) and wheat (cv. Axona) sown at either high (75:25) or low (25:75) pea inclusion rates were harvested after 13 (Cut 1) or 15 (Cut 2) wk. Eighteen Holstein-Friesian cows between wk 9 and 10 of lactation were used in a cyclical changeover design with three 28-d periods. Cows were fed the bi-crop silages and 6 kg of concentrates or second-cut grass silage supplemented with 6 (GS6) or 9 (GS9) kg/d of concentrates. Forage intakes were higher when bi-crops were fed (10.3 to 11.4 kg dry matter [DM]/d) than when grass silage was fed (8.6 kg DM/d). Total DM intake was similar among cows fed the bi-crop silages and GS9 diets, but intakes for GS6 were at least 1.7 kg DM/d lower. Increasing the pea inclusion rate increased the crude protein (CP) content of the ration, but it did not enhance forage quality or animal performance. The rate of intake of the different forages was similar, so that the higher intakes of bi-crop silages were associated with more time spent at the feedbunk and an increased number of meals. Diet digestibility ranged from 531 to 650 g/kg, and the highest value was given by the Cut 1 bi-crop silage diet. Milk yield tended to be similar for cows fed the Cut 2 bi-crop and GS9 diets, and these values were at least 1.7 kg higher than those for cows fed on other treatments. Generally, the bi-crop diets resulted in higher milk fat contents and lower polyunsaturated fatty acid contents. Milk protein content was highest for cows fed the GS9 diet. Blood metabolite content was unaffected by treatment except for blood urea nitrogen content, which was higher in cows fed the bi-crop silages, reflecting reduced N-use efficiency with these diets. The study showed that pea-wheat bi-crop silages can be used to replace moderate-quality grass silage in dairy cow rations, but their role as alternatives to high-quality forages requires additional investigation.

Animal Nutritional Physiological Phenomena↗
PubMed2005

Herbicide-resistant crops and weed resistance to herbicides.

The adoption of genetically modified (GM) crops has increased dramatically during the last 3 years, and currently over 52 million hectares of GM crops are planted world-wide. Approximately 41 million hectares of GM crops planted are herbicide-resistant crops, which includes an estimated 33.3 million hectares of herbicide-resistant soybean. Herbicide-resistant maize, canola, cotton and soybean accounted for 77% of the GM crop hectares in 2001. However, sugarbeet, wheat, and as many as 14 other crops have transgenic herbicide-resistant cultivars that may be commercially available in the near future. There are many risks associated with the production of GM and herbicide-resistant crops, including problems with grain contamination, segregation and introgression of herbicide-resistant traits, marketplace acceptance and an increased reliance on herbicides for weed control. The latter issue is represented in the occurrence of weed population shifts, the evolution of herbicide-resistant weed populations and herbicide-resistant crops becoming volunteer weeds. Another issue is the ecological impact that simple weed management programs based on herbicide-resistant crops have on weed communities. Asiatic dayflower (Commelina cumminus L) common lambsquarters (Chenopodium album L) and wild buckwheat (Polygonum convolvulus L) are reported to be increasing in prominence in some agroecosystems due to the simple and significant selection pressure brought to bear by herbicide-resistant crops and the concomitant use of the herbicide. Finally, evolution of herbicide-resistant weed populations attributable to the herbicide-resistant crop/herbicide program has been observed. Examples of herbicide-resistant weeds include populations of horseweed (Conyza canadensis (L) Cronq) resistant to N-(phosphonomethyl)glycine (glyphosate). An important question is whether or not these problems represent significant economic issues for future agriculture.

Adaptation, Physiological↗
PubMed2005

Mycotrophy of crops in rotation and soil amendment with peat influence the abundance and effectiveness of indigenous arbuscular mycorrhizal fungi in field soil.

Mycotrophy of previous crops has been shown to have an impact on arbuscular mycorrhizal fungi (AMF), and the growth and productivity of succeeding crops. We studied the impact of 3 years of cultivation of eight crops with different degrees of mycotrophy, including mycorrhizal (strawberry, rye, timothy, onion, caraway) and non-mycorrhizal (turnip rape, buckwheat, fiddleneck) hosts, as well as the impact of peat amendment, on the effectiveness, amount and diversity of indigenous AMF. A field experiment having a split-plot design with peat amendment as the main plot, crop cultivation as a sub-plot and three replications, was carried out on silt clay mineral soil in 1999-2001. A well-humified dark peat was applied immediately before establishment of the field experiment. Each year, the relative mycorrhizal effectiveness of soil collected in September, in terms of shoot dry weight (RME(DW)), was determined in a bioassay. In the 3rd year of the experiment, AMF spores were also extracted and identified from the field soil. Expressed as the mean of 3 years of cropping in unamended soil, the mycorrhizal crops strawberry and caraway maintained RME(DW) most effectively, while the values were lower in the non-host crops buckwheat, turnip rape and fiddleneck. In addition, the numbers of AM spores detected in soil were considerably greater during 3 years of strawberry cultivation. In soil under caraway, there were high numbers of AM spores compared to the other crops. In soil amended with peat, the situation was in some cases opposite of that of unamended soil; RME(DW) was highest in rye and onion and lowest in strawberry and caraway. The reasons behind the negative impact of peat on mycorrhizal effectiveness in strawberry soil may be due to the microbiological properties of peat. The importance of including mycotrophic species in crop rotations for maintaining high soil quality and for increasing yields of subsequent crops is discussed.

Agriculture↗
PubMed2000

Barrier crops as a cultural control measure of non-persistently transmitted aphid-borne viruses.

Barrier crops have been used since the early 1950s as a cultural control strategy for reducing the spread of non-persistently transmitted aphid-borne viruses. Since then, this strategy has been investigated by several authors, resulting in a wide range of divergent conclusions on its effectiveness. In a series of field and laboratory experiments carried out in central Spain during 1995-1998, we investigated the efficacy and mode of action of various barrier crops for reducing the spread of Potato virus Y and Cucumber mosaic virus in pepper. The barriers acted as natural 'sinks' for non-persistent viruses and did not reduce the number of aphids landing in the protected crop, as suggested by some authors. There was a significant reduction in virus spread and an increase in yield in two of the four years of trials. Such differences in the effectiveness of the barrier crop strategy show that its efficacy depends on a series of factors such as the kind of virus spread pattern (monocyclic or polycyclic), the height of the barrier crop at the time of maximum risk of infection and the extent of competition between the barrier and the protected crop. Moreover, the barrier crop should not host any potential insect pest or pathogen able to damage the protected crop. It is concluded that use of barrier crops can be an effective crop management strategy to protect against virus infection, but only under specific circumstances.

Animals↗
PubMed1975

Prolactin binding activity on the crop sacs of juvenile, mature, parent and prolactin-injected pigeons.

Specific prolactin (PRL) binding activity of lactoperoxidase catalyzed 125I-labeled ovine-PRL was determined in a membrane-rich particulate fraction of pigeon crop sacs. Levels of TSH, LH or FSH as high as 1000 ng each were unable to displace the 125I-o-PRL bound to 600 mug of crop sac microsomal protein, whereas competitive displacement was achieved with as little as 0.5 ng unlabeled PRL. Ovine GH exhibited some cross reactivity when incubated in amounts greater than 500 ng, but this could be accounted for by its stated PRL contamination. Specific PRL binding activities were determined in juvenile and mature pigeons with unstimulated crop sacs, and parent pigeons with 'crop milk' and mature birds injected with PRL for 4 days. Crop sacs from juvenile birds contained approximately twice as much binding activity as crop sacs from mature pigeons. Parent and PRL injected pigeons, each with proliferated crop sac epithelium, exhibited 4-5 times as much specific PRL binding as the non-proliferated crops from juvenile or mature birds. These results show that the pigeon crop sac contains specific binding sites for PRL, and that the crop sac response to PRL is associated with an increase in PRL binding activity.

Age Factors↗
PubMed2006

Prevalence and numbers of bacteria in broiler crop and gizzard contents.

Crops or gizzards in broiler carcasses are frequently damaged during processing. The contents from either organ, defined by the USDA Food Safety and Inspection Service as ingesta, may contaminate the carcass. Previous research has shown crop contents are a source of Salmonella contamination on processed carcasses, although less information is available on gizzard contents. The purpose of this study was to determine the prevalence and numbers of total aerobic bacteria, coliforms, Escherichia coli, and Campylobacter in ingesta collected from the crop and gizzard. In each of 3 replicate trials, 10 uneviscerated broiler carcasses were obtained from a processor at the shackle transfer point just prior to evisceration. Liquid crop contents and solid gizzard contents were aseptically collected from each carcass and quantitatively cultured. Total aerobic bacteria, coliforms, E. coli, and Campylobacter were determined for contents from both organs. Crop contents (log cfu/mL), compared with gizzard contents (log cfu/g), contained significantly (P < 0.05) higher numbers of total aerobic bacteria (5.6 vs. 2.9), coliforms (4.2 vs. 2.3), E. coli (3.9 vs. 2.2), and Campylobacter (4.6 vs. 2.2). Escherichia coli prevalence was higher in crop samples (28 of 29) than gizzard samples (19 of 30). Campylobacter prevalence was also higher for crop vs. gizzard samples (29 of 29 vs. 12 of 30). An average of 2.4 g of crop contents and 8.4 g of gizzard contents were recovered. Crop contents contain more bacteria than gizzard contents and contained a higher incidence of E. coli and Campylobacter contamination. However, because of the numbers of bacteria and amount of material in the crop and gizzard, it is unlikely that ingesta contamination would increase overall bacterial counts of prechill broiler carcasses.

Animals↗
PubMed1984

Regulation of pigeon crop gene expression by prolactin.

The pigeon crop has long been known as a target tissue for PRL action. This study investigates the molecular events associated with PRL stimulation of the pigeon crop sac. Several experiments were performed comparing isolates from PRL-injected pigeons (200 micrograms/day, im, for 3 days) to saline-treated pigeons. Electrophoretic analysis of crop protein revealed a general pattern of similarity between PRL-stimulated and control isolates, but four major polypeptides were distinctly dissimilar. Two crop peptides (CP) migrating at molecular weight 16,400 and 29,900 (CP16, CP30) were selectively repressed by PRL treatment. In contrast, two products, CP25 and CP154, were dramatically induced in PRL-stimulated crops. Short (4-h) in vivo labeling using tritiated amino acids revealed that polypeptides comigrating with CP16 and CP30 were synthesized only in control crops. A product migrating with CP25 was selectively labeled in PRL-induced crop tissue. To investigate PRL's effect on mRNA populations, polyadenylated RNA was isolated from control or PRL-stimulated crops and translated in a reticulocyte lysate translation system. Gel electrophoresis and fluorography revealed PRL treatment to cause two major differences in the mRNA fractions: repression of a translatable mRNA coding for a product comigrating with CP16 and a large increase in presumptive CP25 mRNA (to 14% of the translatable message). Translation product profiles of mRNA isolated from crops treated locally revealed a dependence of CP25 mRNA induction on the dose of PRL (16-25 micrograms/day). These results show that PRL acts in a direct manner on the crop to regulate specific gene products. Control of two products results from alteration of mRNA levels.

Animals↗
PubMed2006

Proximity to crops and residential exposure to agricultural herbicides in iowa.

Rural residents can be exposed to agricultural pesticides through the proximity of their homes to crop fields. Previously, we developed a method to create historical crop maps using a geographic information system. The aim of the present study was to determine whether crop maps are useful for predicting levels of crop herbicides in carpet dust samples from residences. From homes of participants in a case-control study of non-Hodgkin lymphoma in Iowa (1998-2000), we collected vacuum cleaner dust and measured 14 herbicides with high use on corn and soybeans in Iowa. Of 112 homes, 58% of residences had crops within 500 m of their home, an intermediate distance for primary drift from aerial and ground applications. Detection rates for herbicides ranged from 0% for metribuzin and cyanazine to 95% for 2,4-dichlorophenoxyacetic acid. Six herbicides used almost exclusively in agriculture were detected in 28% of homes. Detections and concentrations were highest in homes with an active farmer. Increasing acreage of corn and soybean fields within 750 m of homes was associated with significantly elevated odds of detecting agricultural herbicides compared with homes with no crops within 750 m (adjusted odds ratio per 10 acres = 1.06; 95% confidence interval, 1.02-1.11). Herbicide concentrations also increased significantly with increasing acreage within 750 m. We evaluated the distance of crop fields from the home at < 100, 101-250, 251-500, and 501-750 m. Including the crop buffer distance parameters in the model did not significantly improve the fit compared with a model with total acres within 750 m. Our results indicate that crop maps may be a useful method for estimating levels of herbicides in homes from nearby crop fields.

Case-Control Studies↗
PubMed2006

Comparison of Salmonella enterica serovar enteritidis levels in crops of fed or fasted infected hens.

Long-term feed withdrawal has been shown to increase ileocecal intestinal colonization and fecal shedding of Salmonella enterica serovar Enteritidis in challenged hens. Less information is available regarding effects of fasting on crop colonization. Two trials were conducted to compare effects of 14-day feed withdrawal vs. full feed on crop colonization in hens challenged with Salmonella Enteritidis. The levels of Salmonella Enteritidis in the crops of fasted hens were significantly higher than in nonfasted hens on days 3 and 10 and days 3, 9, and 16 postinfection (PI) in trials 1 and 2, respectively. Fecal shedding of Salmonella Enteritidis was significantly increased in the fasted hens on day 10 PI in trial 1. Analysis of crop IgA anti-Salmonella Enteritidis lipopolysaccharide levels in crop lavage samples of hens in trial 1 revealed a humoral response PI in both treatment groups with no significant differences, although peak response for fasted hens occurred 1 wk later. Histologic evaluation of hematoxylin and eosin-stained crop sections from trial 1 birds revealed mild to moderate heterophilic infiltration within the crop lamina propria (LP) or LP and epithelium of nonfasted infected hens at 24 and 96 hr PI. In comparison, heterophils in crops of fasted hens infected at this time point were sparse, indicating a possible diminished heterophil response in the fasted birds. Multifocal areas of tissue inflammation, as indicated by marked heterophil infiltration, with necrosis and sloughing of epithelium, were observed in crops from fasted hens at day 11 PI (14th day of feed withdrawal) but not in the fed groups. This severe heterophilic inflammation was observed in both challenged and nonchallenged fasted hens, suggesting that some factor other than Salmonella Enteritidis was responsible. These results indicate that feed withdrawal can have a dramatic effect on the integrity of the crop and its ultimate response to infection.

Animals↗
PubMed1995

Evaluation of the chicken crop as a source of Salmonella contamination for broiler carcasses.

Much previously published research has focused on the role of cecal and intestinal Salmonella contamination of poultry carcasses within commercial processing plants. Presently, we have evaluated the persistence of experimentally inoculated Salmonella enteritidis in the crops and ceca of commercial broiler chickens during the last week of growth (Weeks 6 to 7) and the presence of crop and cecal Salmonella in 7-wk-old broilers in a commercial processing plant. When broilers were inoculated with 1 x 10(6) cfu S. enteritidis at 6 wk of age by oral gavage, the incidence of crop and cecal contamination was equivalent 2d after challenge (30%), with only 1 of 29 crops contaminated and 0 of 29 ceca contaminated at 7 d following challenge. When broilers were inoculated with 1 x 10(8) cfu S. enteritidis at 6 wk of age by oral gavage, 2 d after challenge the crops and ceca were observed to be 57 and 67% positive for S. enteritidis, respectively. Seven days after inoculation with 1 x 10(8) S. enteritidis, the crops and ceca were 37 and 57% positive, respectively, for the challenge organism. At a commercial broiler processing plant, 286 of 550 crops from three flocks were Salmonella-positive, whereas only 73 of 500 ceca from these flocks were contaminated. Furthermore, data from this plant indicated that the crops were far more likely to rupture than ceca (86-fold) during processing, increasing the possibility of carcass contamination with Salmonella derived from crop contents. The results of these studies suggest that the crop may serve as a source of carcass contamination with Salmonella within some processing plants.

Animals↗
PubMed2001

Sex pheromone components in oral secretions and crop of male Caribbean fruit flies, Anastrepha suspensa (Loew).

Chemical analysis of hexane extracts of the oral secretions from male Caribbean fruit flies, Anastrepha suspensa, resulted in identification of pheromone components including: anastrephin, epianastrephin, suspensolide, beta-bisabolene, and alpha-farnesene in a ratio of 63:396:4:8:1. Extracts of the crop from male flies contained these same components. No pheromone was detected in the extracts of female oral secretions. Bioassay of the oral secretions indicated that females were attracted to oral secretions from males but not from females. The amounts of anastrephin and epianastrephin in male oral secretions changed with age and time of the day, and were correlated with the amounts of volatile pheromone components released by male flies. The amounts of suspensolide, beta-bisabolene, and alpha-farnesene in the crop tissue were greater than those in the crop liquid, while amounts of anastrephin and epianastrephin in the crop tissue and crop liquid changed during the day. Generally, the amounts of suspensolide and beta-bisabolene decreased, and the amounts of anastrephin and epianastrephin increased from 9 am to 6 pm in both crop tissue and crop liquid. The amounts of anastrephin and epianastrephin from crop tissue or crop liquid incubated with suspensolide were significantly higher than those of control. The data show that oral secretions deposited on leaves by males contained terpenoid pheromone components that attract females and that suspensolide was converted to anastrephin and epianastrephin by enzymatic degradation in the crop of male flies.

Animals↗
PubMed2003

Managing the pepper maggot (Diptera: Tephritidae) using perimeter trap cropping.

A perimeter trap crop barrier of hot cherry peppers, border-row insecticide applications, and a combination of the two management strategies were evaluated to see if they could protect a centrally located main crop of bell peppers from oviposition and infestation by the pepper maggot, Zonosemata electa (Say). In large plots, the main cash crop of bell peppers was protected from the majority of the oviposition and infestation by all three barriers. The combination sprayed/trap crop barrier provided the best protection against both oviposition and infestation and resulted in over 98% pest-free fruit at harvest. Maggots infested only 1.7% of the main crop fruit when protected by a sprayed or unsprayed trap crop barrier, compared with 15.4% in control plots. The perimeter sprayed/trap crop strategy was employed in three commercial fields in 2000 and 2001. The combination barrier resulted in superior insect control and reduced insecticide use at all commercial locations, compared with the same farms' past history or to farms using conventional and integrated pest management (IPM) methods. Economic analysis showed that the technique is more cost effective and profitable than relying on whole-field insecticide applications to control the pepper maggot. Farmer users were surveyed and found the perimeter trap crop technique simple to use, with many hard-to-measure benefits associated with worker protection issues, marketing, personnel/management relations, pest control and the environment. Use of the perimeter trap crop technique as part of an IPM or organic program can help improve crop quality and overall farm profitability, while reducing pesticide use and the possibility of secondary pest outbreaks.

Agriculture↗
PubMed2003

Insect resistance to transgenic Bt crops: lessons from the laboratory and field.

Transgenic crops that produce insecticidal toxins from the bacterium Bacillus thuringiensis (Bt) grew on >62 million ha worldwide from 1996 to 2002. Despite expectations that pests would rapidly evolve resistance to such Bt crops, increases in the frequency of resistance caused by exposure to Bt crops in the field have not yet been documented. In laboratory and greenhouse tests, however, at least seven resistant laboratory strains of three pests (Plutella xylostella [L.], Pectinophora gossypiella [Saunders], and Helicoverpa armigera [Hübner]) have completed development on Bt crops. In contrast, several other laboratory strains with 70- to 10,100-fold resistance to Bt toxins in diet did not survive on Bt crops. Monitoring of field populations in regions with high adoption of Bt crops has not yet detected increases in resistance frequency. Resistance monitoring examples include Ostrinia nubilalis (Hübner) in the United States (6 yr), P. gossypiella in Arizona (5 yr), H. armigera in northern China (3 yr), and Helicoverpa zea (Boddie) in North Carolina (2 yr). Key factors delaying resistance to Bt crops are probably refuges of non-Bt host plants that enable survival of susceptible pests, low initial resistance allele frequencies, recessive inheritance of resistance to Bt crops, costs associated with resistance that reduce fitness of resistant individuals relative to susceptible individuals on non-Bt hosts ("fitness costs"), and disadvantages suffered by resistant strains on Bt hosts relative to their performance on non-Bt hosts ("incomplete resistance"). The relative importance of these factors varies among pest-Bt crop systems, and violations of key assumptions of the refuge strategy (low resistance allele frequency and recessive inheritance) may occur in some cases. The success of Bt crops exceeds expectations of many, but does not preclude resistance problems in the future.

Bacillus thuringiensis↗
PubMed2002

Improving Intrinsic Water-Use Efficiency and Crop Yield.

Greater yield per unit rainfall is one of the most important challenges in dryland agriculture. Improving intrinsic water-use efficiency (W(T)), the ratio of CO(2) assimilation rate to transpiration rate at the stomata, may be one means of achieving this goal. Carbon isotope discrimination (Delta(13)C) is recognized as a reliable surrogate for W(T) and there have now been numerous studies which have examined the relationship between crop yield and W(T) (measured as Delta(13)C). These studies have shown the relationship between yield and W(T) to be highly variable. The impact on crop yield of genotypic variation in W(T) will depend on three factors: (i) the impact of variation in W(T) on crop growth rate, (ii) the impact of variation in W(T) on the rate of crop water use, and (iii) how growth and water use interact over the crop's duration to produce grain yield. The relative importance of these three factors will differ depending on the crop species being grown and the nature of the cropping environment. Here we consider these interactions using (i) the results of field trials with bread wheat (Triticum aestivum L.), durum wheat (T. turgidum L.), and barley (Hordeum vulgare L.) that have examined the association between yield and Delta(13)C and (ii) computer simulations with the SIMTAG wheat crop growth model. We present details of progress in breeding to improve W(T) and yield of wheat for Australian environments where crop growth is strongly dependent on subsoil moisture stored from out-of-season rains and assess other opportunities to improve crop yield using W(T).

Journal Article↗
PubMed1999

Evaluation of berseem clover in diets of ruminants consuming corn crop residues.

Berseem clover hay was compared to alfalfa hay provided at 0, 25, and 50% of the diet DM in mixtures with corn crop residues to wether lambs. Berseem clover hay had lower (P < .05) concentrations of NDF, ADF, and CP than alfalfa hay. The digestibility of DM, DMI, and N balance did not differ (P > .05) between diets containing alfalfa hay or berseem clover hay. To evaluate stockpiled berseem clover as a supplement for grazed corn crop residues, berseem clover and oats were incorporated into a corn-corn-oat/berseem clover crop rotation for 3 yr in replicated 6.1-ha fields. Two cuttings of oat-berseem clover hay were harvested each summer before forage was stockpiled for winter grazing. After corn grain harvest, multiparous and primiparous crossbred cows in midgestation were allotted to each field at 1.01 ha/cow to strip-graze corn crop residues with or without stockpiled berseem clover or allocated to replicated drylots for 98 to 140 d. Each group was offered alfalfa-grass hay as large bales to maintain a mean body condition score of 5 on a 9-point scale. Mean rates of total and digestible OM disappearance from grazed and ungrazed field areas of berseem clover and corn crop residues did not differ over the 3 yr. In vitro organic matter disappearance (IVOMD) tended to decrease more rapidly (P = .13) and NDF and ADF concentrations increased more rapidly (P < .05) in berseem clover than in corn crop residues. Seasonal BW change did not differ (P > .05) between winter management systems in any year, and seasonal body condition score changes did not differ (P > .05) between cows grazing corn crop residues and berseem clover and those maintained in a drylot in yr 2 and 3. Cows grazing corn crop residues with or without berseem clover required less (P < .05) hay than those maintained in drylot. Although the effects of berseem clover hay supplementation on the intake and digestibility of corn crop residues do not differ from alfalfa hay, the nutritional value of stockpiled berseem clover decreases rapidly during winter, limiting its value as a standing supplement for corn crop residues in late winter.

Animals↗
PubMed1978

[Effect of plant residues on the parasitic activity of soilborne pathogens and the saprophytic microflora of the soil. III. Influence of rye and rape grown as winter catch crop on the incidence of Cercosporella herpotrichoides Fron (author's transl)].

In a five-years field trial, the influence of two winter catchcrops, rye and rape, upon the incidence of Cercosporella herpotrichoides has been studied. The winter catch-crops had been repeated three times, followed either by stubble-crop or without in fall of the fourth year. The variants (blocks) had been completed by two variants without catch-crop, either carefully cultivated or overgrown with weeds. Each of the four blocks had been divided three times to be grown with three different crop sequences containing 80%, 60% (with the insusceptible corn), or 40% haulm fruit, respectively. Each of the 12 variants had been divided into two parts by continuous fallow stripe, one part being artificially infested with the pathogen in the beginning (1st winter wheat). In the 2nd, 3rd, and 4th year, only spring crops were grown, followed by winter wheat in the 5th year. The final exploration resulted in a medium to heavy degree of infection, being significantly higher in the 80% cereal crop sequence than in the 60% and 40% sequences. Concerning the catch-crops, infection in the rye variants was equal or significantly lower than in the carefully cultivated variants without catch-crop. On the other hand, infection of the rape variants had become significantly higher than that of the catch-crop-free ones, about as heavily as in the weed-infested variants. From fall 1966 to summer 1969, the development of the saprophytic soil microflora and several other edaphic parameters had been investigated. Remarkable differences in intensity of disintegration have been observed under the influence of the main crops, cereals or potatoes, respectively, but no differences could be stated resulting from the matter of disintegration--residues of rye or rape--, which might interpret the contrasting effects on the pathogen. Too, no indication for antagonistic activity of bacteria or actinomycetes has been noted. The results are compared with known facts of Cercosporella and of other soil borne pathogens. The difference in biology of Cercosporella on the one hand, and of root infecting fungi on the other hand seems to be most important to explain the results obtained.

Actinomycetales↗
PubMed1985

An investigation into the role of the crop in control of feeding in Japanese quail and domestic fowls.

With normal diets, removal of the crop in Japanese quail and domestic fowls caused reductions in mean meal lengths and sizes, and compensatory increases in meal frequencies, only in those (30-40%) birds that had previously eaten larger, less frequent meals. Sham operation had no such effect. Cropectomy had less effect on feeding activity parameters when quail were fed on a diluted (40% cellulose) diet, and had no effect on diurnal patterns of feeding with either undiluted or diluted food (all birds tending to eat more at the end of the day). This may have been because cropectomized birds could store food in the oesophagus in amounts similar to those previously stored in the crop. Cropectomy had no apparent long-term effect on food intake with undiluted diets, but may have suppressed it slightly with diluted food. In intact quail and fowls, with ad lib access to food when killed, crops were often found to be empty with undiluted food, but were rarely so with diluted food. Gizzards also tended to hold more with diluted food, but were never completely empty with any diet. The post-crop oesophagus and proventriculus were empty in nearly all birds. In quail fasted for two hours, then allowed to feed for 20 min and killed at intervals over a further two hours, maximum amounts of undiluted and diluted food in crops and gizzards were generally greater than in ad lib-fed quail. Crops and gizzards emptied faster with diluted than with undiluted food, but no gizzard was completely empty two hours after feeding. The results of these experiments indicate that, with normal diets, meal termination (satiety) during most of the day is associated with partial crop filling in (30-40%) birds that habitually eat larger, less frequent meals, and with varying degrees of gizzard filling in birds with smaller meals. Satiety involves more crop filling in more birds with diluted food, and this may also apply to other factors that cause increased feeding activity. Meal initiation (hunger) may be associated with partial gizzard emptying in all birds. At some stage towards the end of the day there is usually a conditioned change to cumulative filling of the crop with enough food to be processed overnight.

Animals↗