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The large number of cases of human illness caused by Shiga toxin-producing Escherichia coli (STEC) worldwide has raised safety concerns for foods of bovine origin. These human illnesses include diarrhea, hemorrhagic colitis, hemolytic uremic syndrome, and thrombotic thrombocytopenic purpura. Severe cases end with chronic renal failure, chronic nervous system deficiencies, and death. Over 100 STEC serotypes, including E. coli O157:H7, are known to cause these illnesses and to be shed in cattle feces. Thus, cattle are considered reservoirs of these foodborne pathogens. Because beef and dairy products were responsible for a large number of STEC outbreaks, efforts have been devoted to developing and implementing control measures that assure safety of foods derived from dairy cattle. These efforts should reduce consumers' safety concerns and support a competitive dairy industry at the production and processing levels. The efficacy of control measures both before harvest (i.e., on-farm management practices) and after harvest (i.e., milk processing and meat packing) for decreasing the risk of STEC contamination of dairy products was evaluated. The preharvest measures included sanitation during milking and management practices designed to decrease STEC prevalence in the dairy herd (i.e., animal factors, manure handling, drinking water, and both feeds and feeding). The postharvest measures included the practices or treatments that could be implemented during processing of milk, beef, or their products to eliminate or minimize STEC contamination.

Twenty geldings (five groups; similar age and BW) were used in a completely randomized design experiment to determine effects of grain supplementation of an alfalfa-cube diet on apparent nutrient digestibility and hindgut fermentation. The geldings were housed individually, fed their diets in two equal meals (0600 and 1800), and adapted to five dietary treatments over 6 wk. The treatments were alfalfa cubes (1% of BW; DM basis) without (control) or with one of four rolled cereal grains (i.e., barley, corn, naked oats, or oats) to provide a target level of 0.4% of BW as total nonstructural carbohydrates (TNC). Due to acute laminitis, three geldings (one in the control group and two in the barley group) were excluded. Because of this and multiple incidents of gas colic, TNC level was decreased to 0.2% of BW to ensure the geldings' health throughout the adaptation (7 d) and sample collection (5 d) periods. Grain intakes varied (P < 0.05) and reflected the different TNC concentrations. Apparent digestibilities of DM, OM, CP, NDF, ADF, and cellulose were not affected (P > 0.05) by grain supplementation and averaged 63.2, 63.1, 79.5, 42.7, 39.9, and 50.3%, respectively. Regardless of the source, grain supplementation increased (P < 0.05) apparent digestibility of TNC (from 85.6 to 94.6%) and decreased (P < 0.05) fecal pH (from 7.04 to 6.74). Fecal concentrations of total VFA (mg/g of DM) were greatest for the barley and naked oats diets (averaging 11.73), intermediate for the oats diet (8.00), and least for the control and corn diets (averaging 5.00; P < 0.05). Fecal concentrations of lactate (microg/g of DM) were greatest for the barley diet (254), intermediate for the oats diet (138), and least for the remaining diets (averaging 100; P < 0.05). Fecal concentrations of NH3 N (mg/g of DM) were greatest for the naked oats diet (1.68), intermediate for the barley and oats diets (averaging 0.86), and least for the remaining diets (averaging 0.63; P < 0.05). Serum concentration of lactate was 46% higher (P < 0.05) for the control than for the grain diets (averaging 0.05 mg/100 mL). Feeding barley, corn, naked oats, and oats contributed to 13, 15, 8, and 20% higher (P < 0.05) serum NH3 N concentrations than the control diet (0.25 mg/100 mL). Higher (P < 0.05) serum concentrations of urea N (mg/100 mL) were detected for the control, barley, and naked oats diets (averaging 25.28) than for the corn or oats diets (averaging 22.21). Results suggest that horses consuming alfalfa cubes could be supplemented with rolled barley, corn, naked oats, or oats at levels not exceeding 0.2% of BW as TNC without affecting nutrient digestion or overall health negatively.

Fructans are fermentable carbohydrates and include short-chain fructooligosaccharides (scFOS), inulin, and hydrolyzed inulin (oligofructose, OF). Two studies with dogs were designed to examine the effects of low concentrations of fructans on nutrient digestibilities, fecal microbial populations, and endproducts of protein fermentation, and fecal characteristics. In Exp. 1, 11 adult male beagles were fed corn-based, kibbled diets supplemented with or without OF to provide 1.9 +/- 0.6 g/d. Dietary inclusion of OF decreased (P < 0.05) nutrient digestibilities, but did not affect fecal characteristics. Increasing OF concentration tended (P < 0.06) to linearly decrease fecal ammonia concentrations, but not those of branched-chain fatty acids (BCFA), amines, indole, or phenols. Fecal concentrations of total short-chain fatty acids (SCFA) and butyrate tended to be higher in OF-supplemented dogs (P < 0.10), as was the ratio of bifidobacteria to total anaerobes (P = 0.15). In Exp. 2, ileally cannulated adult female hounds were fed a meat-based kibbled diet and were assigned to four scFOS treatments (0, 1, 2, or 3 g/d) in a 4 x 4 Latin square design. Ileal nutrient digestibilities tended to increase (P < 0.15) with increasing concentrations of scFOS. On a DMI basis, fecal output tended to decrease linearly (P < 0.10) in response to increasing scFOS supplementation, whereas fecal score tended to exhibit a quadratic response (P = 0.12). In general, fecal concentrations of SCFA, BCFA, ammonia, phenols, and indoles were not altered by supplemental scFOS. Supplementation of scFOS increased fecal concentrations of total aerobes (P < 0.05) and decreased concentrations of Clostridium perfringens (P < 0.05). From these data, it seems that low levels of supplemental fructans have divergent effects on nutrient digestibility and fermentative endproducts, but do not adversely affect nutrient digestibility or fecal characteristics and may improve colonic microbial ecology in dogs.

Mercury (Hg), especially in organic form, is a highly toxic pollutant affecting plants, animals, and man. In plants, the primary target of Hg damage is the chloroplast; Hg inhibits electron transport and photosynthesis. In the present study, chloroplast genetic engineering is used for the first time to our knowledge to enhance the capacity of plants for phytoremediation. This was achieved by integrating a native operon containing the merA and merB genes (without any codon modification), which code for mercuric ion reductase (merA) and organomercurial lyase (merB), respectively, into the chloroplast genome in a single transformation event. Stable integration of the merAB operon into the chloroplast genome resulted in high levels of tolerance to the organomercurial compound, phenylmercuric acetate (PMA) when grown in soil containing up to 400 micro M PMA; plant dry weights of the chloroplast transformed lines were significantly higher than those of wild type at 100, 200, and 400 micro M PMA. That the merAB operon was stably integrated into the chloroplast genome was confirmed by polymerase chain reaction and Southern-blot analyses. Northern-blot analyses revealed stable transcripts that were independent of the presence or absence of a 3'-untranslated region downstream of the coding sequence. The merAB dicistron was the more abundant transcript, but less abundant monocistrons were also observed, showing that specific processing occurs between transgenes. The use of chloroplast transformation to enhance Hg phytoremediation is particularly beneficial because it prevents the escape of transgenes via pollen to related weeds or crops and there is no need for codon optimization to improve transgene expression. Chloroplast transformation may also have application to other metals that affect chloroplast function.

Unsporulated oocysts were detected in the feces of an Arabian red fox (Vulpes vulpes arabica) between 6 and 8 days after it had been fed meat from Arabian mountain gazelles (Gazella gazella) known to contain sarcocysts. No oocysts were discovered in the feces of other experimental cubs, although sporocysts of Sarcocystis spp. were passed subsequently by all cubs that were fed gazelle meat, including those fed with reem (G. subgutturosa marica). The oocysts sporulated in 3 days at room temperature (25 +/- 2 C); they were 10.9 +/- 1.4 x 10.1 +/- 1.3 microm, with 2 sporocysts measuring 6.0 +/- 0.6 x 4.7 +/- 0.8 microm, each with 4 sporozoites. Sporulated oocysts were identified as those of Hammondia heydorni using molecular and standard morphometric techniques. Sequence differences between 2 fox and 3 dog isolates of H. heydorni were detected and allowed differentiation between the 2 populations of the organism. The involvement of Neospora caninum was excluded using molecular methods. The Arabian red fox and the Arabian mountain gazelle in Saudi Arabia are new, definitive and intermediate hosts for H. heydorni.

The pH (i.e., 5.5, 5.75, 6.0, 6.25, 6.5, 6.75, 7.0, and 7.25) effect on Escherichia coli O157:H7 in an artificial rumen model was investigated. Eight fermenters were inoculated with bovine rumen fluid and were supplied with a diet (75 g of dry matter daily in 12 equal portions [every 2 hr]) containing similar forage-to-concentrate ratio. After an adaptation period (i.e., 3 days for adjusting the rumen fluid [pH 6.2] microbial population to the test pH and 4 days for adjustment to the diet at the test pH), each fermenter was inoculated with 10(9) cells of E. coli O157:H7. Samples were collected hourly for 12 hr and every 2 hr for an additional 12 hr and were analyzed by flow cytometer. E. coli O157:H7 could not be quantified after 24 hr, and detection was only possible after enrichment. Because the pathogen could not be detected 5 days postinoculation (i.e., Day 13), the fermenters were reinoculated with E. coli O157:H7 on Days 17 and 22. E. coli O157:H7 numbers decreased from 10(6) to 10(4)/ml of fermenter contents in a quadratic (P < 0.05) fashion over the 24-hr sampling period, and the rate of reduction was slower (P < 0.05) for pH 7.0 than for other pH treatments. Results suggested that E. coli O157:H7 population were decreased by competitive exclusion and were not affected by culture pH.

Worldwide, verotoxin-producing Escherichia coli (VTEC) have been recognized as the cause of many sporadic cases or major outbreaks of human illnesses involving consumption of contaminated meat, especially beef. Although sheep products have not been linked to reported human illnesses, their role as a food safety risk factor should not be ignored. The objective of this study was to assess VTEC prevalence in two groups of ewes (20 each) grazing an irrigated pasture or arid range in a western United States environment (Nevada) over 1 year (summer of 1999 to summer of 2000). A random sample (n = 504) of potential VTEC isolates were tested for verotoxicity and were screened for the presence (polymerase chain reaction [PCR]) and expression (VTEC-reversed passive latex agglutination assay) of the toxin genes (i.e., VT1 and VT2). Forty-one VTEC isolates (16 having only the VT1 gene and 25 having both VT1 And VT2 genes) were detected in both groups of ewes. Except for seven isolates, the genotype and phenotype data matched. All the isolates (nonmotile [H-]) were non-O157:H7 VTEC (i.e., O91:H- [n = 25], O128:H- [n = 9], and untypeable ones [n = 7]). More infected ewes (nine versus three) and different VTEC strains were found in the irrigated pasture than in the arid range. Because our ewes were shedding two VTEC serotypes known to cause human illnesses, it is beneficial to identify VTEC-positive sheep before slaughter as an initial control point before entering the food chain.

The objective of this study was to assess prevalence of verotoxin-producing Escherichia coli (VTEC) in culled beef cows at the time of shipping to slaughter. Feces were collected from 82 cows on eight Nevada ranches during fall and winter (from September to January) after grazing rangeland forages. A random sample (n = 154) of potential VTEC isolates were tested for verotoxicity and were screened for the presence (polymerase chain reaction) and expression (VTEC-reversed passive latex agglutination assay) of the toxin genes (i.e., VT1 and VT2). Seventeen isolates from four ranches were VTEC. Of these, four had the VT1 gene, five had the VT2 gene, seven had both genes, and one did not have either gene despite its toxicity to Vero cells. Except for one isolate (i.e., untypeable that reacted with VT1-latex beads without having VT1 gene), the genotype and phenotype data of the VTEC isolates matched. Another isolate (O8:H- [nonmotile]) was verotoxic, but neither had nor expressed the toxin genes. Of the 17 isolates, four (from one cow) were O157:H7, 11 (from five cows on three ranches) were non-O157:H7 (two O8:H-, three O105:H-, three O116:H-, and three O141:H-), and two were untypeable. Because some of these VTEC serotypes (i.e., O8:H-, O141:H-, and O157:H7) are known to cause human illnesses, it is beneficial to identify VTEC-positive cows before slaughter. This is a critical step in any pre- or post-harvest strategy to minimize the risk of beef contamination with such pathogens.

Verotoxin-producing Escherichia coli (VTEC) have emerged in the past two decades as food-borne pathogens that can cause major outbreaks of human illnesses worldwide. The number of outbreaks has increased in recent years due to changes in food production and processing systems, eating habits, microbial adaptation, and methods of VTEC transmission. The human illnesses range from mild diarrhea to hemolytic uremic syndrome (HUS) that can lead to death. The VTEC outbreaks have been attributed to O157:H7 and non-O157:H7 serotypes of E. coli. These E. coli serotypes include motile (e.g., O26:H11 and O104:H21) and nonmotile (e.g., O111:H-, O145:H-, and O157:H-) strains. In the United States, E. coli O157:H7 has been the major cause of VTEC outbreaks. Worldwide, however, non-O157:H7 VTEC (e.g., members of the O26, O103, O111, O118, O145, and O166 serogroups) have caused approximately 30% of the HUS cases in the past decade. Because large numbers of the VTEC outbreaks have been attributed to consumption of ruminant products (e.g., ground beef), cattle and sheep are considered reservoirs of these food-borne pathogens. Because of the food safety concern of VTEC, a global perspective on this problem is addressed (Exp Biol Med Vol. 228, No. 4). The first objective was to evaluate the known non-O157:H7 VTEC strains and the limitations associated with their detection and characterization. The second objective was to identify the VTEC serotypes associated with outbreaks of human illnesses and to provide critical evaluation of their virulence. The third objective was to determine the rumen effect on survival of E. coli O157:H7 as a VTEC model. The fourth objective was to explore the role of intimins in promoting attaching and effacing lesions in humans. Finally, the ability of VTEC to cause persistent infections in cattle was evaluated.

A site that covers over 20 acres of coastal saline depression in the western Mediterranean coastal desert of Egypt (El-Hammra station, the main crude oil pipeline terminal in Al-Alamein) is contaminated with crude oil spill as a result of activities from refineries, oilfield blowouts, tanker and pipeline break-ups. This area, prior to contamination, was dominated by different common halophytes. However, Limoniastrum monopetalum is now the only species found growing in the oil-contaminated soil. A specific question addressed in the present study was: what are the biochemical changes occurring in a desert plant growing in oil-contaminated soils? Major metabolites such as proline, betaine, free amino acids, fatty acid esters and mineral elements were studied. The plant samples were collected from the oil-contaminated, as well as noncontaminated, sites. The higher concentration in the selected organic metabolites in the plants growing in the contaminated site compared to those in noncontaminated site may be due to differences in a number of receptors. The sensitivity of such receptors for the environmental signal that cause differences in genetic expression leads to differences in physiological processes. The change in the landscape of the contaminated area and the elimination of the natural vegetation, except L. monopetalum, may explain the competitive balance toward the oil-resistant species.

Long-term feedlot studies have shown positive effects (i.e., improved ADG and reduced morbidity and mortality) of dietary supplementation with ethoxyquin (AGRADO). This may be due to improving the antioxidant capacity at the ruminal, postruminal, or postabsorption levels. This study was designed to investigate the role of ethoxyquin at the rumen level. A finishing diet (12.5% CP; DM basis) was formulated to contain (on a DM basis) 77.5% flaked corn, 10% corn cobs, 10% protein/vitamin/mineral supplement, and 2.5% tallow. In a randomized complete block design experiment, the treatments were arranged as a 2 x 2 factorial. The main factors were two ethoxyquin treatments (without or with 150 ppm) and two monensin/tylosin treatments (without or with monensin and tylosin at 0.0028 and 0.0014% of dietary DM, respectively). Eight dual-flow, continuous culture fermenters were used in two experimental periods (blocks; 8 d each with 5 d for adjustment and 3 d for sample collection) to allow for four replications for each treatment. No interactions (P > 0.05) were detected for any of the measurements evaluated. Therefore, results of the main factors were summarized. Ethoxyquin supplementation improved (P < 0.05) true digestibility of OM (from 38.8 to 45.0%) but it did not alter (P > 0.05) concentrations of total VFA (averaging 131 mM) or acetate (averaging 58.8 mM). Ethoxyquin decreased (P < 0.05) propionate concentration from 51.1 to 42.4 mM and increased (P < 0.05) butyrate concentration from 18.4 to 22.9 mM. Digestion of total nonstructural carbohydrates was not altered (P > 0.05) by the treatments and averaged 86%. With the exception of increased (P < 0.05) concentration of propionate (from 42.0 to 51.5 mM) and decreased (P < 0.05) concentration of butyrate (from 25.9 to 16.3 mM), no effects (P > 0.05) were detected for monensin/tylosin. Ruminal N metabolism, including efficiency of bacterial protein synthesis (averaging 21.2 g N/kg OM truly digested), was not affected (P > 0.05) by the treatments. Results suggest positive effects of ethoxyquin on ruminal digestion of OM and unique changes in VFA production.

The worldwide contamination of foods and feeds with mycotoxins is a significant problem. Mycotoxins are secondary metabolites of molds that have adverse effects on humans, animals, and crops that result in illnesses and economic losses. Aflatoxins, ochratoxins, trichothecenes, zearelenone, fumonisins, tremorgenic toxins, and ergot alkaloids are the mycotoxins of greatest agro-economic importance. Some molds are capable of producing more than one mycotoxin and some mycotoxins are produced by more than one fungal species. Often more than one mycotoxin is found on a contaminated substrate. Factors influencing the presence of mycotoxins in foods or feeds include environmental conditions related to storage that can be controlled. Other extrinsic factors such as climate or intrinsic factors such as fungal strain specificity, strain variation, and instability of toxigenic properties are more difficult to control. Mycotoxins have various acute and chronic effects on humans and animals (especially monogastrics) depending on species and susceptibility of an animal within a species. Ruminants have, however, generally been more resistant to the adverse effects of mycotoxins. This is because the rumen microbiota is capable of degrading mycotoxins. The economic impact of mycotoxins include loss of human and animal life, increased health care and veterinary care costs, reduced livestock production, disposal of contaminated foods and feeds, and investment in research and applications to reduce severity of the mycotoxin problem. Although efforts have continued internationally to set guidelines to control mycotoxins, practical measures have not been adequately implemented.

Shiga toxin-producing Escherichia coli (STEC) produce toxins that have been associated with several human illnesses. E. coli O157:H7 is the most well-studied STEC and was first associated with consumption of improperly cooked ground beef in 1982. E. coli O157:H7 is not the only foodborne STEC because other STEC serotypes are also associated with human illnesses. The objective of this study was to assess prevalence of STEC in 23 yearling beef (Angus) heifers grazing an irrigated grass pasture in spring (April), summer (July), fall (October), and winter (December) of 1999. A total of 86 fecal samples were rectally collected and were subjected to microbiological testing for the presence of STEC. Nine E. coli isolates from five heifers (one in spring and fall and three in winter) were toxic to Vero cells. Of these isolates, four were E. coli O157:H7, two belonged to the serogroup O6, one O39:NM, one O113:H-, and the final isolate was untypable. The STEC prevalence rate in our herd ranged from 4% (spring) to 15% (winter). Based on detecting both O157:H7 and non-O157:H7 STEC in our heifers, it is clear that screening fecal samples should not be limited to E. coli O157:H7. Identification of STEC-positive cattle prior to slaughter should help in reducing the risk of beef contamination with such foodborne pathogens if pre- and/or postharvest control measures are applied to such animals.

Verotoxin-producing Escherichia coli (VTEC) produce one or two toxins known as VT1 and VT2. These toxins have been associated with several human illnesses. Dairy cattle harboring VTEC represent a potential health hazard because they enter the food chain as ground beef. The objective of this study was to assess the occurrence of VTEC in dairy heifers. A total of 91 fecal samples were rectally collected during four periods (spring, summer, fall, and winter of 1999) from 23 heifers. A random sample (n=530) of potential VTEC isolates were tested for verotoxicity and were screened by the polymerase chain reaction (PCR) for presence or absence of VT1 and/or VT2 genes. Thirteen isolates from two heifers (from the winter collection) were verotoxic and were confirmed as E. coli. VTEC were only detected during winter with an occurrence rate of 9.5%. Using PCR, five isolates had the VT1 gene while the remaining eight had the VT2 gene. The sequence and expression of VT1 and VT2 genes were confirmed. No E. coli O157:H7 was detected, but serotyping revealed that the five VT1-positive isolates were O26:NM (a non-motile strain of O26). The remaining eight isolates were untypeable. Identification of VTEC-positive cattle before slaughter is a critical step in any on-farm strategy to minimize the risk of beef contamination with such pathogens.

The prevalence of Sarcocystis species in muscle samples from gazelles kept as breeding groups at the King Khalid Wildlife Research Centre, Saudi Arabia, was determined by fibreoptic examination, pepsin digestion and histological techniques. No macroscopic sarcocysts were detected by fibreoptic examination, and the overall prevalence of Sarcocystis was 66 x 7 per cent by pepsin digestion, and 39 x 9 per cent by histological examination. By digestion, the tongue contained the highest density of bradyzoites in Gazella dorcas, and Gazella gazella erlangeri, the oesophagus in Gazella subgutturosa marica and skeletal muscle in Gazella gazella and Gazella thomsoni. Skeletal muscle was least affected in G dorcas, the oesophagus in G gazella, and the diaphragm in G g erlangeri, G s marica and G thomsoni. By histology, the heart contained most microcysts, except in G g erlangeri, in which the tongue was most affected. No single tissue type was therefore suitable for the diagnosis of sarcocystosis in this multispecies collection, although digestion was more sensitive in detecting infection than histology. The level of Sarcocystis infection was significantly higher in free-ranging gazelles kept in a main enclosure than in gazellas kept in breeding pens, and higher in adult gazelles than in juveniles.

In situ and in vivo digestibility experiments were conducted to determine the acceptability, digestibility, and safety of a return chewing gum/packaging (G/P) material mixture when fed to steers. In the in situ experiment, both ruminal and intestinal disappearances were measured. Two ruminally and duodenally cannulated steers, which were given free access to alfalfa hay (AH), were used in this study. Duplicate Dacron bags containing the G/P were incubated in the rumen for 0, 3, 6, 12, 24, and 48 h. After ruminal incubation, the 12-, 24-, and 48-h bags were placed in the duodenum and collected in the feces to determine intestinal disappearance. In situ ruminal DM disappearance was greater than 70% for all substrates tested at 0 h, indicating high solubility of the substrates in water, and began to reach a plateau after 12 h of incubation. Intestinal in situ disappearance was not different (P>.25) from zero. In the digestion trial, four ruminally cannulated steers (337+/-21.3 kg BW; mean +/- SD) were used in a 4x4 Latin square design with the following treatments: 0) 50% corn (C), 50% AH; 10) 45% C, 45% AH, 10% G/P; 20) 40% C, 40% AH, 20% G/P; 30) 35% C, 35% AH, 30% G/P. Steers fed G/P-containing diets had greater (P<.01) DMI than the control steers. Increasing the G/P resulted in a linear (P<.05) increase in DMI. Apparent DM digestibility tended to be higher (P<.10) for the G/P-containing diets than for the control. A quadratic effect (P<.05) on digestible DMI was observed, with greater (P<.01) digestible DMI values for G/P-containing diets (4.8 vs. 5.8 kg/d). Digestible organic matter and total nonstructural carbohydrate intakes followed trends similar to those of DM. Apparent aluminum digestibility of G/P-containing diets was not different (P>.13) from zero. The level of G/P in the diet had no effect (P>.2) on total VFA concentration or ruminal pH. There was a linear decrease (P<.01) in the molar percentage of isobutyrate and isovalerate in addition to a linear increase (P<.01) in butyrate and valerate with increasing levels of G/P. There was a quadratic effect (P<.01) on molar proportions of acetate and propionate and on the acetate:propionate ratio. Results of both experiments suggest that G/P may be fed to safely replace up to 30% of corn-alfalfa hay diets for growing steers with advantages in improving DMI and digestibility.

Published data on intestinal microbiota of dogs and cats are limited but suggest the presence of a complex and diverse colonic bacterial population (34 genera including 129 species) the majority of which are anaerobes. During the colonic fermentation of endogenous and undigested amino acids, several putrefactive compounds (i.e., ammonia, aliphatic amines, indoles, phenols and volatile sulfur-containing compounds) are produced and are responsible for the malodor of dog and cat feces. These fecal odor components also have been implicated as causes of colorectal cancer; therefore, dietary manipulation of gut microbiota towards a potentially more remedial community (Bifidobacterium and Lactobacillus) is gaining more attention. The health benefits derived from dietary supplementation of prebiotics (e.g., oligofructose and inulin) have been documented in humans. However, little is known of a potentially similar role in companion animals. Feeding another prebiotic (i.e., lactosucrose) to dogs or cats is reported to increase the numbers of bifidobacteria and decrease the numbers of pathogens and the concentration of fecal odor components. In our laboratory, oligofructose supplementation numerically decreased the concentrations of ammonia and amines and increased the numbers of bifidobacteria in dog feces.

In Exp. 1, soybean hull samples were obtained from nine sources across the United States and analyzed for nutrient content to determine their suitability for inclusion in dog diets. Compositional data revealed variation in both the amount of total dietary fiber (TDF; 63.8 to 81.2%) in the soybean hulls and the ratio of insoluble:soluble fiber (5.0:1 to 15.4:1). Crude protein content varied widely among sources, ranging from 9.2 to 18.7%. An in vivo trial (Exp. 2) was conducted using a premium dog diet containing 3.0, 4.5, 6.0, 7.5, or 9.0% soybean hulls (DM basis). There was a negative linear effect (P < .05) of soybean hull inclusion in the diet on DM, OM, TDF, and GE total-tract digestibilities, as well as on calculated ME. Crude protein and fat digestibilities were unaffected by treatment. Based on these results, ileally cannulated dogs were fed diets containing 6.0, 7.5, or 9.0% soybean hulls (DM basis) in addition to diets containing either 0% supplemental fiber or 7.5% beet pulp (Exp. 3). Nutrient digestion at the ileum was unaffected by inclusion of supplemental fiber. Total tract digestion of DM, OM, and GE was lower ( P < .05) for diets containing supplemental fiber when compared with the diet containing 0% fiber. Crude protein and fat digestibilities were unaffected by treatment. There was no difference in nutrient digestibility between those diets containing soybean hulls and a diet containing beet pulp. Soybean hull inclusion in the diet resulted in a negative linear effect (P < .05) on calculated ME, in addition to lowering ME (P < .05) when compared with the 0% fiber control diet. Calculated ME for dogs fed a 7.5% beet pulp-containing diet was lower (P < .05) than that for dogs fed the soybean hull-containing diets. Results indicate that soybean hulls can be an effective dietary fiber source in dog diets.

The objectives of these studies were to predict the effects of roasting and extrusion temperatures of whole soybeans (SB) on intestinal protein digestibility in cattle. Intestinal digestibility was assessed with a two-stage in vitro or in situ ruminal incubation/precision-fed cecectomized rooster bioassay. In Exp. 1, whole SB (raw SB or SB roasted to 141, 149, or 157 degrees C exit temperature from a commercial roaster and steeped for 30 min) were incubated in strained ruminal fluid and McDougall's buffer (50:50) at 39 degrees C for 16 h. In Exp. 2, SB (ground raw SB or SB extruded at 116, 138, or 160 degrees C) were placed in polyester bags (20 x 30 cm) and suspended in the ventral rumen of steers for 16 h. Lyophilized residue of the in vitro or in situ incubations and samples of raw SB and most extensively heated SB (roasted SB at 157 degrees C or extruded SB at 160 degrees C) for each respective experiment were crop-intubated to cecectomized roosters. Total excreta were collected for 48 h after intubation and lyophilized, and amino acid (AA) concentrations were determined. In Exp. 1, total AA digestibility was 61.6 and 84.5% for unincubated whole raw SB and 157 degrees C roasted SB, respectively, and 66.2, 88.9, 91.3, and 91.6% for in vitro residues of whole raw SB and SB roasted at 141, 149, and 157 degrees C, respectively. Trypsin inhibitor (TI) activity was 20.09, 1.69, 1.54, and 1.84 mg/g fat-free DM for unincubated whole raw SB and 141, 149, and 157 degrees C roasted SB, respectively, and 30.84, 1.01, .90, and .26 mg/g fat-free DM for in vitro residues of whole raw SB, 141, 149, and 157 degrees C roasted SB, respectively. In Exp. 2, total AA digestibility was 68.5 and 87.7% for unincubated ground raw SB and 160 degrees C extruded SB, respectively, and 81.9, 91.3, 89.7, and 89.4% for in situ residues of ground raw SB and 116, 138, and 160 degrees C extruded SB, respectively. Trypsin inhibitor activity was 17.61, 4.89, 4.08, and 1.56 mg/g fat-free DM for unincubated ground raw SB, 116, 138, and 160 degrees C extruded SB, respectively, and 3.62, .59, .55, and .21 mg/g fat-free DM for incubated ground raw SB, 116, 138, and 160 degrees C extruded SB, respectively. Heat treatment by roasting and extrusion improved AA digestibilities of SB, but there were no differences detected among the roasting or extrusion temperatures. Ruminal fermentation did not eliminate the negative effects of TI activity on intestinal digestibility of AA in whole SB but did reduce TI activity in ground SB.

Cellulose casings are used to contain and form meat and poultry emulsions during the smoking and cooking process. Casings then are stripped from the cooked product and traditionally disposed of in landfills. Because of the bulk of the spent cellulose casings (SCC), rapid composting technology may be used to reduce bulkiness. The following SCC were evaluated in vitro and in vivo: fibrous ground (FG), fibrous composted (FC), NOJAX ground (NG), and NOJAX composted (NC). In vitro digestibility was determined by incubating SCC with mixed ruminal bacteria for 0, 6, 12, 24, 36, 48, and 72 h. In vivo data were collected using four ruminally cannulated Holstein steers in a 4 x 4 Latin square design. Diets consisted of a 50:50 ratio of alfalfa hay-wheat middlings with 5% cornsteep liquor. Diets contained no SCC (CON) or 25% (DM basis) of the FC, FG, or NC SCC substrate. Casings were high in structural carbohydrate and salt content but low in CP, ether extract, and lignin concentrations. In vitro OM digestibility at 24 h was highest (P < .05) for FC and lowest (P < .05) for NG; FG and NC were intermediate. Composting tended to reduce fiber content and increase digestion. In vivo intakes and digestibilities were not adversely affected by inclusion of SCC in the diet. Thus, SCC have the ability to partially replace more traditional forages, such as alfalfa hay and wheat middlings, in high-fiber diets for growing beef cattle. Limitations in the use of SCC as a partial replacement of traditional feedstuffs will likely be because of high salt concentrations in the casings resulting from product brine chilling.

The objective was to determine the effects of dietary forage percentage and fat supplementation on ruminal N metabolism, duodenal flows of AA, and digestion of N. Six ruminally and duodenally cannulated steers were offered six isonitrogenous diets for ad libitum intake twice daily in a 6 x 6 Latin square design. Treatments were arranged as a 2 x 3 factorial with two forage percentages (70 vs. 30% of dietary DM as corn silage) and three forms of canola seed supplementation, including no canola seed or canola seed added at 10% of dietary DM as whole seed treated with alkaline H2O2 or as crushed seed. No interactions between dietary forage percentage and canola seed supplementation occurred for any of the measurements. Duodenal flows of NAN and AA were greater for diets containing low forage than for diets containing high forage. However, duodenal flows of total N and NAN did not differ among diets when corrected for differences in intake. Efficiency of bacterial protein synthesis and duodenal flows of bacterial N and AA were increased when treated whole canola seed was supplemented. Apparent total tract digestibility of N was not altered by dietary forage percentage or canola seed supplementation. Results indicate that fat supplementation from canola seed (at 5% of dietary DM), in either form, had no effects on ruminal N metabolism or flows of AA to the duodenum and suggest that treated whole canola seed may stimulate ruminal bacterial protein synthesis.

The objective was to evaluate the effectiveness of alkaline H2O2 treatment of whole canola seed as a means of weakening the seed coat while simultaneously protecting long-chain unsaturated fatty acids from ruminal biohydrogenation without hindering their digestion in the lower gut. Six ruminally and duodenally cannulated beef steers were offered six isonitrogenous diets for ad libitum intake twice daily in a 6 x 6 Latin square design. Treatments were arranged as a 2 x 3 factorial with two forage percentages (70 vs. 30% of dietary DM as corn silage) and three forms of canola seed supplementation, including no canola seed or canola seed added at 10% of dietary DM as treated whole seed or as crushed seed. Canola seed contributed 5% added fat to the total diet. Treated whole canola seed was superior to crushed seed in increasing the amounts of C18:1, C18:2, and C18:3 flowing to the duodenum and the amounts digested postruminally. However, digestibilities of these long-chain fatty acids (as percentages of the amounts entering the small intestine) did not differ between diets containing canola seed as treated whole seed or crushed seed. Results suggest that chemically treated whole canola seed can be used as a means of postruminal delivery of digestible long-chain unsaturated fatty acids, especially C18:1, which contributes 62% of the total fatty acids in canola seed. Results also suggest that treated whole canola seed may be more beneficial when fed with low than with high forage diets.

The objective of this study was to determine the effects of source of dietary CP and level of ruminally protected lysine and methionine (RPLM) on feedlot performance and carcass characteristics of Holstein steers during a growing-finishing trial (266 d). A total of 168 Holstein steers (182.7 +/- 27.5 kg) were used in a completely randomized design experiment (eight treatments; three pens of seven steers/treatment). Steers were given ad libitum access to high-concentrate diets (13% CP) containing 71% whole shelled corn, 10% corn silage, 4% condensed distillers solubles, and 15% protein supplements (DM basis). Treatments were arranged as a 2 x 4 factorial. The main factors were two sources of dietary CP and four levels of RPLM. The sources of dietary CP were soybean meal (SBM) or SBM and urea (SBM-U). Urea-N replaced 50% of SBM-N in the SBM-U diet. The levels of RPLM were 0, 5, 10, and 15 g per steer daily. No interactions (P > .10) between source of dietary CP and level of RPLM were observed for feedlot performance or carcass characteristics. Feedlot performance showed an advantage (P < .10) to feeding SMB during the first 84 d of the trial and an advantage to feeding SBM-U during the last 98 d of the trial. However, feedlot performance for the whole trial and carcass characteristics (except for fat thickness) were not affected (P > .10) by the source of dietary CP. Steers fed diets containing SBM-U had 12% less (P < .10) fat thickness than those fed diets containing SBM. Supplementation of diets with increasing levels of RPLM did not affect (P > .10) ADG or carcass characteristics. However, DMI and gain:feed showed cubic (P < .10) responses to increasing dietary level of RPLM. Supplementation of RPLM at the 10 g/d level improved gain:feed by 12% during the last 98 d of the trial, and this was a direct response to the cubic effects of RPLM on DMI. Results suggest a cost advantage for replacing 50% of SBM-N with that from urea in high-corn diets without negative effects on feedlot performance or carcass characteristics of growing-finishing Holstein steers with extended feeding periods (266 d). These types of diets seem to meet the amino acid requirements and are not limiting in lysine and methionine.

We evaluated the influence of gastrointestinal tract microflora from several species on fiber fermentation characteristics in vitro. Selected fibrous substrates (cellulose, beet pulp, citrus pulp, and citrus pectin) were incubated for 6, 12, 24, and 48 h with ruminal fluid from cattle or feces from dogs, cats, pigs, horses, or humans. When data were pooled across all substrates and fermentation times, OM disappearance (29.4%) and acetate, propionate, butyrate, and total short-chain fatty acid (SCFA) production (1.09, .41, .12, and 1.61 mmol/g of OM, respectively) were lowest (P < .05), and lactate production (.23 mmol/g of OM) was greatest (P < .05) for horse fecal microflora compared with samples from the other species. The greatest (P < .05) acetate production resulted when substrates were fermented by cat fecal microflora (2.38 mmol/g of OM). The greatest (P < .05) propionate productions resulted from pig fecal and cattle ruminal microflora (.88 and .83 mmol/g of OM, respectively), and the greatest (P < .05) butyrate productions resulted from human and pig fecal microflora (.39 and .40 mmol/g of OM, respectively). Total SCFA production was greatest (P < .05) for cat fecal microflora (3.38 mmol/g of OM). When data were pooled across the species, substrate OM disappearance and SCFA production ranked from least to greatest in the following order: cellulose < beet pulp < citrus pulp < citrus pectin. The fermentability of different fibrous substrates by fecal or ruminal microflora from various species seems to be dependent not only on the fermentative activity of the microbial population but on other factors as well, perhaps lag time and rate of digesta passage.

The objective was to compare the relative energy value of wet corn gluten feed (WCGF) to that of corn in a feedlot situation when diets were initially offered ad libitum (AL) or at restricted feed intake (RFI; 80% of AL). In a completely randomized block (pen location) design experiment, 144 beef heifers (204.1 +/- 18.2 kg) were used (six treatments; three pens of eight heifers/treatment). Treatments were levels of WCGF (on DM basis) in corn silage-based diets (AL; 25 or 50% WCGF) or high-moisture corn-based diets (RFI; 0, 25, 50, or 75% WCGF) during the growing phase (127 d). During finishing (84 d), all diets were offered AL and contained 5% corn silage by replacing corn silage with high-moisture corn in diets that were offered AL. Heifers that were initially at AL had similar (P > .1) feedlot performance (during growing and during the whole trial), digestibility of nutrients (OM, NDF, CP, and GE), and carcass characteristics. During finishing, however, these heifers had better (P = .06) ADG and gain:feed when 25% WCGF was fed. Heifers that were initially at RFI showed a linear decrease (P < .01) in ADG and gain:feed during growing with increasing dietary level of WCGF. However, increasing dietary level of WCGF resulted in a quadratic (P = .02) response in ADG and gain:feed during finishing and also in a quadratic (P = .07) response in ADG and a linear (P = .005) decrease in gain:feed during the whole trial. These quadratic responses indicated that the best performance was achieved at the 25 and 50% levels of WCGF. The decrease in cumulative gain:feed was only 3.5% at the 25 and 50% levels of WCGF but it was 11.4% at the 75% level. Increasing the level of WCGF in diets of heifers that were initially at restricted feed intake did not affect (P > .1) digestibility of nutrients but it improved some carcass characteristics linearly, decreasing fat thickness (P = .04), liver abscess (P = .02), and yield grade (P = .13). Results suggest that WCGF can substitute up to 25 or 50% of dietary DM without negative effects on feedlot performance, digestibility of nutrients, or carcass characteristics. In addition, restricting feeding during growing may be strategy that improves the utilization of WCGF at these levels.

The objective of this study was to examine the effects of dietary forage level and fat supplementation on the chemical composition of mixed ruminal bacteria (MRB). Six ruminally cannulated beef steers (354 kg +/- 18) were given ad libitum access to six diets (13.2% CP; DM basis) that were offered twice daily in a 6 x 6 Latin square design. Treatments were arranged as a 2 x 3 factorial with two forage levels (70 vs 30% of dietary DM as corn silage) and three forms of fat supplementation including no canola seed or canola seed added at 10% of dietary DM as whole treated with alkaline hydrogen peroxide or untreated crushed. Canola seed contributed 5% added fat to the total diet. The remaining dietary ingredients were corn, canola meal, molasses, and urea. No interactions (P > .05) between dietary forage level and canola seed supplementation were observed. Concentrations of OM, N, and all amino acids were higher (P < .05) in MRB from steers fed low forage than in MRB from steers fed high forage. Concentrations of purines and GE and the N:purines ratio in MRB were not affected (P > .05) by dietary forage level or canola seed supplementation. Canola seed supplementation did not affect (P > .05) concentrations of OM, N, or most of the amino acids in MRB. Concentrations of four essential amino acids (i.e., isoleucine, leucine, lysine, and phenylalanine) in MRB were decreased (P < .05) due to canola seed supplementation. Dietary forage level did not affect (P > .05) concentrations of long-chain fatty acids in MRB.(ABSTRACT TRUNCATED AT 250 WORDS)

The objective of this study was to determine the effects of fat supplementation from canola seed (CS) on ruminal fermentation and postruminal digestion of OM, carbohydrates, and energy of diets containing different levels of forage. Six ruminally and duodenally cannulated beef steers (354 kg +/- 18) were given ad libitum access to six isonitrogenous diets that were offered twice daily in a 6 x 6 Latin square design. Treatments were arranged as a 2 x 3 factorial with two forage levels (70 vs 30% of dietary DM as corn silage) and three forms of CS supplementation including no CS or CS added at 10% of dietary DM as whole CS treated with alkaline hydrogen peroxide or untreated crushed CS. Fat from CS provided 5% of dietary DM. The remaining dietary ingredients were corn, canola meal, molasses, and urea. No interactions (P > .05) between dietary forage level and CS supplementation were observed for ruminal characteristics or digestion of OM, carbohydrates, and energy in the rumen, postruminally, or in the total tract. Fat supplementation from CS did not affect (P > .05) DMI. With few exceptions, fat supplementation did not affect (P > .05) ruminal, postruminal, or total tract digestibilities of OM, structural and nonstructural carbohydrates, and GE. Ruminal disappearance of GE was decreased (P < .05) when diets were supplemented with fat from whole treated CS, and total tract digestibilities of OM and GE were decreased (P < .05) when diets were supplemented with fat from CS in either form. Ruminal pH, concentrations of NH3 N and total VFA, and molar proportions of acetate, propionate, and butyrate were not affected (P > .05) by fat supplementation. Results suggest that fat supplementation from CS (at 5% of dietary DM) as whole treated or untreated crushed had no negative effects on ruminal fermentation of OM, carbohydrates, or energy when steers were given ad libitum access to diets containing high or low forage.

The objective was to determine the effects of altering ruminal CP degradation of soybean meal (SBM) by roasting (Exp. 1) on ruminal characteristics and extents of in situ disappearance of DM, OM, and fiber components (Exp. 2). A control diet (8.2% CP) containing oat hulls, corn silage, starch grits, ammoniated corn cobs, and molasses was supplemented to 17.1% CP with unroasted SBM (SBM-0) or SBM roasted at 165 degrees C for 75, 150, or 210 min (SBM-75, SBM-150, and SBM-210, respectively). In Exp. 1, SBM was incubated for 0, 2, 4, 8, 12, 16, and 24 h in the rumen of two steers that were fed the SBM-0 diet. Extents of ruminal CP degradation and rates of N disappearance decreased (P < .05) linearly with increasing roasting time of SBM. In Exp. 2, five ruminally cannulated steers were used in a 5 x 5 Latin square design and were fed the five diets listed above during five 11-d periods. On d 11, five substrates (alfalfa hay, orchardgrass hay, corn silage, soy hulls, and wheat straw) were incubated in the rumen for 24 h. Extents of in situ disappearance of DM, OM, and fiber (NDF, ADF, cellulose, hemicellulose, and total dietary fiber) were analyzed as a split-plot design. No substrate x diet interaction (P > .05) was observed for any of the measurements evaluated. Extents of in situ disappearance (24 h) of DM, OM, and fiber were highest (P < .05) when the control diet was fed and were lowest (P < .05) when the SBM-0 diet was fed. Decreasing the availability of SBM protein in the diet by roasting increased (P < or = .10) extents of in situ disappearance of DM, OM, and fiber linearly. These extents were similar for steers fed the control diet or the diet containing SBM-210. Ruminal concentrations of NH3 N, branched-chain VFA, and valerate were highest (P < .05) and ruminal pH lowest (P < .05) when the SBM-0 diet was fed. Results indicated a rapid ruminal fermentation of both protein and readily available carbohydrates of SBM (resulting in pH below 6.0) during the first 4.5 h after feeding the SBM-0 diet. Making both protein and readily available carbohydrates of SBM more slowly fermentable by roasting slowed early fermentation processes, maintained higher ruminal pH, and encouraged earlier and faster ruminal fiber digestion.

Six mature wethers (BW 72 kg) with ruminal, duodenal, and ileal cannulas were fed a basal (no added soybean meal [SBM]) diet or diets containing unheated SBM or SBM roasted at 165 degrees C for 75, 150, 180 or 210 min in a 6 x 6 Latin square experiment. Concentrations of indicators of heat exposure (NDF, ADF, and ADIN) in SBM increased with increasing roasting time. Organic matter digestion characteristics were not affected (P > .05) by supplementation or roasting of SBM. Daily intakes of NDF, ADF, and ADIN were higher (P < .05) when wethers were fed SBM-containing diets than when they were fed the basal diet and also were higher (P < .05) when wethers were fed diets containing roasted SBM than when fed the diet containing unheated SBM. Roasting time of SBM had a quadratic effect (P < .05) on intakes of NDF, ADF, and ADIN, with the lowest intakes observed for diets containing unheated SBM or SBM roasted for 75 min and the highest intakes observed for diets containing SBM roasted for 180 or 210 min. Disappearance of ADF in the stomach (grams per day) was not affected by supplementation or roasting of SBM. Disappearance of NDF and ADIN in the stomach (grams per day) were higher (P < .05) when wethers were fed SBM-containing diets than when they were fed the basal diet and also were higher (P < .05) when wethers were fed diets containing roasted SBM than when they were fed those containing unheated SBM.(ABSTRACT TRUNCATED AT 250 WORDS)

Cobalt glucoheptonate as a source of Co to enhance ruminal fiber digestion was evaluated in two in vitro digestibility experiments. In Experiment 1, Co supplementation (0, 5, and 10 ppm) of five substrates (leaf and stem fractions of alfalfa and orchardgrass hays and ground corn) was evaluated under two dietary conditions (ruminal fluid taken from steers fed alfalfa hay or a high concentrate diet) for 24 or 48 h of fermentation in a 3 x 5 x 2 x 2 factorial arrangement. In Experiment 2, four concentrations of Co (0, 10, 20, and 30 ppm) were added to five substrates (alfalfa hay, orchardgrass hay, corn cobs, recycled newsprint treated with HCl, and cellulose casings) and were incubated with ruminal fluid from steers fed alfalfa hay for 24 or 48 h of fermentation in a 4 x 5 x 2 factorial arrangement. No interactions among treatments were observed for digestibilities of DM, OM, or NDF in both experiments or for VFA concentrations in Experiment 1. Supplementation with Co did not increase digestibilities of DM, OM, or NDF in either experiment or concentrations of VFA in Experiment 1. In Experiment 1, in vitro digestibilities of DM, OM, and NDF were higher for inoculum from steers fed alfalfa versus concentrate. In Experiment 2, digestibilities of DM, OM, and NDF were highest for alfalfa hay and lowest for recycled newsprint treated with HCl. Cobalt concentrations that were above minimum requirements did not improve digestion of DM, OM, or fiber.

We determined the antibody prevalence of toxoplasmosis (Toxoplasma gondii infections) in antelopes in Saudi Arabia. Serum samples from 324 Gazella subgutturosa marica, 202 Gazella gazella, 70 Gazella dorcas, and 12 Arabian oryx (Oryx leucoryx) were tested by the indirect hemagglutination test. Antibodies to T. gondii were detected in 13(4.0%) G. subgutturosa marica, 12(5.9%) G. gazella, 3(4.3%) G. dorcas, and in none of the Arabian oryx sampled. More adult gazelles were seropositive than juveniles; males and females were similar. The highest reciprocal antibody titer recorded (262,144) was in a G. subgutturosa marica serum.

Fish meal (FM) as a protein supplement in ruminant diets is presented to illustrate production responses to FM supplementation and to explain the possible factors that may affect the magnitude of these responses. Positive responses are consistently detected when FM is fed to nonruminants, but the responses when fed to ruminants have lacked consistency. Research indicates that ruminal protein degradation of FM is affected by processing factors including type and freshness of fish, addition of preservatives, stabilization of fat, type of dryer used, temperature and duration of heating, and the amount of fish solubles added back to the meal. Performance data published in the last two decades have been categorized into body weight gain and milk yield and composition. Fish meal was more effective in improving body weight gain in young than in finishing ruminants and in males than in females or castrated males. Daily gains and feed efficiencies were higher when FM supplemented medium- or poor-quality silages than when it was added to high-quality silages. No significant advantage was found for replacing protein sources that were highly ruminally degradable with FM in high-corn diets fed to growing ruminants. Milk yield and milk protein concentration were improved by FM supplementation of low-concentrate diets fed to cows in early lactation. However, milk fat percentage was negatively affected by FM supplementation. Reproduction data indicated that body gain and conception rates of high-producing cows were improved by supplementing their diets with FM during early lactation. Results suggest a significant advantage of FM supplementation to ruminant diets if the physiological status of the animal and the quality of the dietary ingredients are taken into account.

Four diets containing 15% CP were formulated to study the effects of dietary carbohydrate and protein sources on N metabolism and carbohydrate fermentation by ruminal bacteria. Diets were supplied to eight dual-flow continuous culture fermenters during three experimental periods in a randomized complete block design. Six replications were obtained for each diet. Treatments were arranged as a 2 X 2 factorial with two carbohydrate and two protein sources. Carbohydrate sources were corn and barley and protein sources were soybean meal (SBM) and fish meal (FM). Approximately 40% of the dietary CP was derived from SBM or FM and corn or barley provided 39% of dietary DM. All diets contained 15% grass hay, 20% wheat straw, and 10.1 to 15.3% solka floc (DM basis). Interactions (P less than .05) were observed between dietary carbohydrate and protein sources, resulting in a depression of VFA production (moles/day) and digestion (percentage) of ADF and cellulose when the corn-FM diet was fed. True OM digestion (percentage) was higher (P less than .05) for SBM than for FM diets and for corn than for barley diets. Although dietary CP degradation (percentage) was higher (P less than .05) for SBM than for FM diets, non-NH3 N in the effluent (grams/day) was not different among diets due to a greater (P less than .05) bacterial N flow for SBM than for FM diets. Despite the lower amino acid (AA) intake (P less than .05) for corn than for barley diets and also for FM than for SBM diets, flows (grams/day) of total AA, essential AA (EAA), and nonessential AA (NEAA) were similar (P greater than .05) among diets. However, greater (P less than .05) total AA, EAA, and NEAA flows (percentage of AA intake) were found for corn than for barley diets and for FM than for SBM diets. It is concluded, therefore, that ruminal escape protein derived from corn or FM has a significant effect on manipulating AA leaving the ruminal fermentation.

Eight wether lambs fitted with ruminal, duodenal, and ileal cannulas were used in a replicated 4 x 4 Latin square design to study the effects of carbohydrate and protein sources on ruminal protein metabolism and carbohydrate fermentation and intestinal amino acid (AA) absorption. Treatments were arranged as a 2 x 2 factorial. Carbohydrate sources were corn and barley; protein sources were soybean meal (SBM) and fish meal (FM). Diets contained 15.5% CP, of which 40% was supplied by SBM or FM. Corn or barley provided 39% of dietary DM that contained equal amounts of grass hay and wheat straw. Fish meal diets produced a lower (P less than .05) ruminal NH3 concentration and resulted in less CP degradation and bacterial protein flow to the duodenum than did SBM diets. Replacing SBM with FM increased (P less than .05) ruminal digestion of all fiber fractions. In addition, cellulose and hemicellulose digestibilities in the rumen tended to increase (P greater than .05) when barley replaced corn in the FM diets. Carbohydrate x protein interactions (P less than .05) were observed for OM digestion in the rumen and AA absorption in the small intestine (percentage of AA entering); these interactions were highest for the barley-FM diet. These results suggest that feeding FM with barley, which is high in both degradable carbohydrate and protein, might benefit ruminants more than feeding FM with corn, which is high in degradable carbohydrate but relatively low in degradable protein.

An in situ protein degradation trial and two growth trials were conducted to evaluate the use of fish meal (FM) as a protein supplement in feeder lamb diets. Finn cross and Hampshire lambs were given ad libitum access to corn diets, minerals, and water. In Growth Trial 1, four isonitrogenous (12.6% CP on a DM basis) and isocaloric (77% TDN) diets were supplemented with the following: a) 100% soybean meal (SBM); b) 70% SBM + 30% FM; c) 40% SBM + 60% FM; and d) 100% FM on a DM basis. Diets were fed to 144 lambs for 56 d in a randomized complete block (initial BW) design. In Growth Trial 2, four diets were fed to 80 lambs for 42 d in a completely randomized design with treatments arranged as a 2 x 2 factorial. Main effects in Growth Trial 2 were dietary CP level (13.3 or 14.9%) and source (SBM or SBM + FM). Alfalfa hay was used as the roughage part of each diet. In situ CP degradation (determined in cattle) of SBM, FM, and corn fed in both growth trials were 77.8, 52.3, and 56.8%, respectively. In neither growth trial was ADG affected (P greater than .05) by dietary CP source. Lambs gained faster (P less than .05) when the CP level was increased from 13.3 to 14.9% in Growth Trial 2. In both trials, protein efficiency ratio (grams of gain/grams of protein intake) and energy efficiency ratio (grams of gain/kilograms of TDN intake) were not different (P greater than .05) among diets. Because of the low ruminal degradation of corn protein, the relative value of SBM and FM in full-fed, high-corn diets was comparable.

Several media were tested for the release of Onchocerca raillieti microfilariae from skin snips and for their subsequent in vitro maintenance. Tyrode's solution containing 20% equine serum and antibiotics was the best medium tested, followed by phosphate buffered saline. Tyrode's solution alone or distilled water were poor media. A temperature 7-12 degrees C lower than the host's body temperature favoured release of the microfilariae from skin snips. The microfilariae were best maintained at 4-10 degrees C, when they remained alive for up to 5 days. O. raillieti microfilariae had an evening periodicity which could be related to a possible vector's peak of feeding activity.

A study undertaken to determine the Onchocerca species infecting camels that live in the same localities as cattle in the Dinder Region, Blue Nile Province, Sudan revealed concurrent infections with the bovine parasites Onchocerca armillata in the thoracic aorta, brachiocephalic trunks and brachial arteries and Onchocerca gutturosa in the ventral side of the lamellar parts of the ligamentum nuchae. The microfilariae of both species had the same predilection sites in the skin of the ears, head and neck regions. Those of O. gutturosa outnumber those of O. armillata but both are smaller than the respective uterine microfilariae. Males and microfilariae of both species are smaller than those of cattle origin.

Goats are highly susceptible to Haemonchus longistipes and could therefore serve as an inexpensive model to study camel haemonchosis. The course of the disease in goats is similar to that in camels and to H. contortus infection in sheep and goats. Unlike the age-dependency of camel haemonchosis, however, the severity of H. longistipes infection in goats is dose-dependent and varies from mild to hyperacute.

Cattle of various ages from Khartoum Province and western Sudan were surveyed for Onchocerca armillata infection by skin snip examination and some also at post-mortem examination. The former method reliably detected infection in cattle aged between nine months and eight years. Several of the older infected animals had no microfilariae in their skin. Prevalence rate and number of microfilariae per gram of skin were higher in male than in female cattle and in animals from western Sudan than those from Khartoum province. Severe pathological changes were seen in the thoracic aorta, brachiocephalic, costocervical and brachial arteries and posteriorly in the abdominal aorta to its bifurcation into the iliac arteries.

Camel haemonchosis is prevalent in the Sudan, especially during the rainy season, with a decrease in prevalence in the dry season possibly due to delayed maturation of the worms. The naturally occurring disease in Sudanese camels is characterized by emaciation, anaemia, oedema of the lower parts of the limbs, eosinophilia, hypoproteinaemia, hypoalbuminaemia, hyperglobulinaemia and eosinophilia, as well as elevated blood urea concentrations.

Onchocerca raillieti was found to be prevalent in Sudanese donkeys. The parasite was reported from Central, Northern, Western and Eastern Sudan and was most predominant in the last locality. The pathological changes produced by adult worms in the ligamentum nuchae are mostly chronic and do not seem to cause any clinical manifestations. Likewise, the microfilariae, though found in high densities in the skin with a "spill over" into the eyes, produce no pathological changes in either the skin or eyes.