Clostridial abomasal disease in Connecticut dairy calves

Over 2 years, 24 dairy calves died of emphysematous abomasitis and abomasal bloat. Anaerobic cultures of necrotic abomasal mucosa yielded Clostridium perfringens from 10 of 15 calves. Sarcina were observed in 17 of 22 examined histologically. A change in the antibiotic regimen for newborns and improved sanitizing of feeding utensils eliminated further losses.     

Estimating leukocyte,platelet, and erythrocyte counts in rats by blood smear examination

Background: The CBC is an essential test for assessing the health of rats used in drug development studies. Because of limited blood volume, estimates of cell counts from a blood smear would be valuable when other analytical methods of enumerating cells are not possible or available. Objective: The purpose of this study was to develop a statistical model to accurately estimate WBC, platelet (PLT), and RBC counts in blood smears from rats. Method: Blood smears and quantitative cell counts were obtained from vehicle‐treated male and female Fischer 344 rats (n=65) involved in a variety of studies. The numbers of WBCs, PLTs, and RBCs were estimated in 10 fields in the monolayer of smears using × 20 (WBC) or × 100 (PLT, RBC) objectives. Using a statistical model and the quantitative cell counts obtained on an ADVIA 120 hematology analyzer, formulas were developed to predict the quantitative counts from the estimates. Results: Data were log‐transformed before analysis. A formula was derived using the slope and intercept of the regression line between cell estimates and ADVIA counts to predict WBC, PLT, and RBC counts based only on estimates. A second formula was developed for situations in which limited quantitative analyses may be available, and resulted in even more accurately predicted counts from smear estimates. Conclusion: The formulas developed in this study can be a valuable tool in estimating cell counts from a blood smear when cell counting instruments are not available or when an instrument cell count needs to be verified. These formulas may be useful in the assessment of rat blood in discovery and lead optimization studies.     

Principles and Practice of Therapeutic Exercise for Horses

Physical therapists are an integral component of the medical team in human health care. They are backed by a solid foundation of basic science and clinical research. Veterinarians have only recently begun to incorporate physical therapy into clinical practice, but without formal research that validates therapeutic interventions specific to equine patients. The purpose of this article is to present a series of therapeutic exercises adapted for horses based on knowledge and experience of human physical therapy, equine biomechanics, and the types of movement dysfunction commonly seen in the performance horse. Injuries, lameness and musculoskeletal pain syndromes, frequently encountered in equine practice, are disorders that may be successfully addressed with physical therapy. Incorporating standard therapeutic interventions based on clinical success in humans, basic science research, or expert opinion is possible with the understanding that these techniques will ultimately be accepted or refuted when their success or failure is formally documented. This review is designed to stimulate discussion and encourage research that will add to the knowledge base and lead to effective therapeutic protocols in the equine patient.     

Effect of ammonium sulfate,ammonium chloride and root‐zone acidity on inorganic ion content of tobacco

Tobacco plants (Nicotiana tabacum L. cv NC82) were supplied with (NH₄)₂SO₄, or NH₄Cl at root‐zone pH of 6.0 and 4.5 in hydroponic culture for 28 days. Dry matter accumulation, total N and C content, and leaf area and number were not affected by the NH₄ ⁺ source or root‐zone pH. Plants supplied with NH₄C1 accumulated up to 1.2 mM Cl g DW^‐1, but accumulated 37% less inorganic H₂PO₄ ^‐ and 47% less SO₄ ^2‐ than plants supplied with (NH)₂SO₄. The large Cl^‐ accumulation resulted in NH₄C1 –supplied plants having a 31% higher inorganic anion (NO₃ ^‐, H₂, PO₄ ^‐, SO₄ ^2‐, and Cl^‐) charge. This higher inorganic anion charge in the NH₄C1‐supplied plants was balanced by a similar increase in K⁺ charge. Plants supplied with NH₄Cl accumulated greater concentrations of Cl^‐ in leaves (up to 5.1% of DW) than plants supplied with (NH₄)₂SO₄ (less than ‐% DW). Despite the high Cl^‐ concentration of leaves in NH₄Cl supplied plants, these plants showed no symptoms of Cl^‐ toxicity. This demonstrates that toxicity symptoms are not due solely to an interaction between high Cl^‐ concentration in tissue and NH₄ ⁺ nutrition. The increase in root‐zone acidity to pH 4.5 from 6.0 did not induce toxicity symptoms.     

Partitioning of biomass in water‐ and nitrogen‐stressed cotton during pre‐bloom stage

The partitioning of biomass between aboveground parts and roots, and between vegetative and reproductive plant parts plays a major role in determining the ability of cotton (Gossypium hirsutum L.) to produce a crop in a given environment. We evaluated the single and combined effects of water and N supply on the partitioning of biomass in cotton plants exposed to two N supply levels, 0 and 12 mM of N, and two water regimes, well irrigated and water‐stressed at an early reproductive stage. The N treatments began when the third true leaf was visible, while water deficit treatments were imposed over the N treatments when the plants were transferred into controlled‐environment chambers at a leaf area near 0.05 m². Both water deficits and N deficits inhibited total biomass accumulation and its partitioning in cotton. Water deficit alone and N deficit alone inhibited the growth of leaves, petioles, and branches, but did not inhibit growth of the stem and enhanced the accumulation of biomass in squares. When water deficit was superimposed on N deficit, leaf growth was inhibited, although to a lesser extent than when it was the sole stress factor, and the accumulation of biomass in squares was also inhibited. Yet, the dry weight of squares in plants exposed to water and N deficits was greater than that of non‐stressed plants. Water and N deficits, either alone or in combination, did not inhibit the growth of the tap root. Growth of lateral roots was not inhibited either by water deficit alone or in combination with N deficit, but was enhanced when plants were exposed to N deficit alone. Exposure to water deficit alone or in combination with N deficit decreased the shoot:root ratio through the inhibition of shoot growth. Exposure to N deficit alone decreased the shoot:root ratio through the combination of shoot growth inhibition and root growth enhancement.     

Assessing the Value of Using a Remote Sensing-Based Evapotranspiration Map in Site-Specific Management

ABSTRACT

In the glaciated regions of the northern Great Plains, water - either too much or too little - influences soil development, carbon storage, and plant productivity. Integrating site-specific water variability information directly into management is difficult. Simulation models that employ remotely sensed data can generate hard to measure values such as evapotranspiration (ET). This information can be used to identify management zones. The objective of this study was to determine if the METRIC (Mapping Evapotranspiration at High Resolution and with Internalized Calibration) model, which uses weather station and remote sensing data can be used as a tool in site-specific management. This study was conducted on a 65 ha corn (Zea mays L.) field located in east central South Dakota. The METRIC model used Landsat 7 data collected on August 4, 2001 to calculate ET values with spatial resolution of 30 m. ET values were correlated with corn yield (r = 0.85??), apparent electrical conductivity (EC_a; r = 0.71??), soil organic carbon (SOC; r = 0.32?), and pH (r = 0.28?). In the footslope positions, high ET values were associated with high corn yields, SOC, EC _a , and pH values, while in the summit/shoulder areas low ET values were associated with low yields, SOC, EC_a, and pH values. The strong relationship between ET and productivity was attributed to landscape processes that influenced plant available water, which in turn influenced productivity. Cluster analysis of the ET and EC data showed that these data bases complimented each other. Remote sensing-based ET data was most successful in identifying areas where water stress reduced corn yields, while EC_a was most successful in identifying high yielding management zones. Findings from this study suggest that remote sensing-based ET estimates can be used to improve management zone delineation.     

NITROGEN FERTILIZER MANAGEMENT FOR IMPROVED GRAIN QUALITY AND YIELD IN WINTER WHEAT IN OKLAHOMA

From 2002 to date, a long-term field experiment has been conducted at Lake Carl Blackwell, Oklahoma, with different rates and times of nitrogen (N) fertilizer application to determine their effect on grain yield, protein and N uptake of winter wheat. Trend analysis for N rates (0, 50, 100, 150 and 200 kg N ha^?1) and orthogonal contrasts for different application times (pre-plant, top-dressed in February and March) were performed. With increasing fertilizer N, wheat grain yield and protein content increased from 2110 kg ha^?1 to 6783 kg ha^?1 and from 8.96 to 17.19%, respectively. For grain yield, protein, and N use efficiency, split applications of N fertilizer were much more efficient than applying all N pre-plant. Large differences in grain yields were noted for different years at the same N rate (range exceeded 5.0 Mg ha^?1) and that illustrated the need for making within-year-specific N rate recommendations.     

Feed Form Affects Growth and Stomach Ulcers in Yearling Horses

Fourteen yearling standardbred horses were used to test the hypothesis that hay and grain fed as a complete total mixed ration （TMR） cube diet （C） would result in greater average daily gain （ADG）, feed efficiency （gain to feed ratio, G/F） and apparent digestibility in horses on the TMR diet compared to horses fed the same weight and proportion of hay cubes and grain fed separately （diet HG）. Both diets consisted of 75% forage and 25% ground oats. The forage in both the plain hay cubes and the complete cubes was 80% alfalfa and 20% endophyte-free tall rescue. An additional hypothesis that stomach ulceration would not differ between horses fed either of the two diet treatments was also tested by comparing upper gastric endoscopies before and after 70 days of feeding the experimental diets. Horses fed diet C had greater ADG （P 〈 0.046） while G/F between the two treatments was not significantly different （P 〉 0.065） but showed a trend to be higher in the horses consuming diet C. Apparent digestibility of dry matter and crude protein was not different between the diet treatments, and no major gastric ulceration was found in horses consuming either diet treatment. The results of this study found that a complete cubed diet of 75% hay and 25% oats did not cause stomach ulceration while achieving an acceptable growth rate in yearling horses.