D- VS L-methionine utilization by growing steers

Increasing the amino acid supply to the small intestine of growing cattle can increase performance, if specific amino acids are limiting. Although this can be accomplished by feeding rumen undegradable protein, a more economical approach may be supplementing only those amino acids that actually limit performance, but in a form that will bypass the rumen. Methionine (MET) is thought to be a limiting amino acid for growing cattle. DL-MET, a 50 :50 mixture of natural methionine (L-MET) and the unnatural optical isomer (D-MET) is used widely in monogastric rations. Ruminally protected DL-methionine is also available for cattle; however, little information is available about its utilization by growing steers. We studied the efficiency of utilization of D- vs L-MET by growing steers by measuring nitrogen retention of steers postruminally supplemented with graded levels of D- or LMET. Nitrogen retention increased linearly in response to infusion of both L-MET and D-MET, with similar responses for the two isomers. The efficiency of utilization of DMET relative to L-MET was estimated to be 95.5%. In conclusion, D-MET was similar to L-MET in increasing nitrogen retention of growing steers

Flotation therapy for downer cows

Cattle that become recumbent (unable to get up) as the result of calving difficulty, low blood calcium, traumatic injuries, or other disorders are prone to develop subsequent pressure damage of muscles, nerves, and areas of skin. The resulting medical problems that are secondary to prolonged recumbency may be more life-threatening than the initial medical disorder that caused recumbency. Flotation therapy is an effective means of physical therapy for rehabilitation of downer cattle. A description of flotation therapy and data from the first year of use of the flotation tank at the Veterinary Medical Teaching Hospital, Kansas State University, are presented.; Dairy Day, 1996, Kansas State University, Manhattan, KS, 1996

Continuous-culture fermentation as a tool for forage evaluation

Ruminal degradation of organic matter and protein in alfalfa and prairie hay were evaluated in vivo, using cannulated cows, and in vitro, using a continuous-culture fermenter to simulate ruminal fermentation. Estimates of organic matter degradability, microbial N flow per unit feed N input, and efficiency of microbial growth were not different (P\u3e.10) between the in vivo and in vitro systems. However, for both forages, estimates of nitrogen degradability were greater with the in vitro system. Despite the differences between in vivo and in vitro techniques for some variables, continuous-culture fermentation will allow us to compare the effects of dietary treatments on forage digestion and will aid in the formulation of supplements to meet specific nutrient requirements for cattle consuming forage-based diets

Influence of increasing proportion of supplemental nitrogen from urea on intake and fermentation characteristics in beef steers consuming low-quality, tallgrass-prairie forage

Five ruminally and duodenally fistulated Angus × Hereford steers were used to determine intake and fermentation responses associated with increasing the proportion of supplemental degradable intake protein (DIP) provided by urea. Steers had free access to a dormant, tallgrass-prairie forage. The supplemental DIP was provided by sodium caseinate and (or) urea , at a level that was determined previously to optimize use of a similar forage. Supplemental DIP was balanced with corn starch to provide a final supplement of 40% crude protein. Percentages of DIP from urea were: 0, 25, 50, 75, and 100%. Supplements were given intraruminally. Increasing the percentage of urea as supplemental DIP from urea did not significantly affect forage DM intake; however, fermentation characteristics changed

Complete quantum control of exciton qubits bound to isoelectronic centres

In recent years, impressive demonstrations related to quantum information processing have been realized. The scalability of quantum interactions between arbitrary qubits within an array remains however a significant hurdle to the practical realization of a quantum computer. Among the proposed ideas to achieve fully scalable quantum processing, the use of photons is appealing because they can mediate long-range quantum interactions and could serve as buses to build quantum networks. Quantum dots or nitrogen-vacancy centres in diamond can be coupled to light, but the former system lacks optical homogeneity while the latter suffers from a low dipole moment, rendering their large-scale interconnection challenging. Here, through the complete quantum control of exciton qubits, we demonstrate that nitrogen isoelectronic centres in GaAs combine both the uniformity and predictability of atomic defects and the dipole moment of semiconductor quantum dots. This establishes isoelectronic centres as a promising platform for quantum information processing

Zero modes of six-dimensional Abelian vortices

We analyze the fluctuations of Nielsen-Olesen vortices arising in the six-dimensional Abelian-Higgs model. The regular geometry generated by the defect breaks spontaneously six-dimensional Poincar\'e symmetry leading to a warped space-time with finite four-dimensional Planck mass. As a consequence, the zero mode of the spin two fluctuations of the geometry is always localized but the graviphoton fields, corresponding to spin one metric fluctuations, give rise to zero modes which are not localized either because of their behaviour at infinity or because of their behaviour near the core of the vortex. A similar situation occurs for spin zero fluctuations. Gauge field fluctuations exhibit a localized zero mode.Comment: 45 pages in Revtex style with 4 figure

Surgical treatment of a complicated distal tibia epiphyseal Salter–Harris type I fracture in a yearling

This article describes the management of a complicated distal epiphyseal Salter–Harris type I fracture of the left tibia in a yearling horse. Closed reduction and internal fixation was attempted in the first surgery using tension band wires. Due to fracture instability 2 weeks after surgery, a full‐limb transfixation pin cast was applied to the tibia and maintained for 7 weeks to prevent further fracture displacement and to achieve axial alignment. The full‐limb cast was maintained for a total of 12 weeks, including the time with the transfixation pin cast. Cast sores and tendon laxity resolved without further complications. Ten months after the first surgery, the fracture had radiographically healed, and the horse was sound at the walk and trot in a straight line

Are Paleomagnetic Records From U‐Channels Appropriate for Studies of Reversals and Excursions?

Sampling of sediment cores using plastic U‐channels has made possible the acquisition of detailed records of paleomagnetic secular variation, geomagnetic polarity, environmental magnetic studies, and relative paleointensity over the past several million years. U‐channel measurements provide the great advantage of rapid measurements of long sediment cores, but the signal resolution is attenuated by the response function of the magnetometer sensors, which therefore restrains the recovery of rapid and large‐amplitude field changes. Here we focus on the suitability of the dynamics of reversals and excursions derived from U‐channel measurements. We compare successive individual paleomagnetic directions of 1.5 cm × 1.5 cm × 1.5 cm cubic discrete samples with those of a 1.5‐m equivalent U‐channel sample train obtained by placing the samples adjacent to each other. We use varying excursion and transition lengths and generate transitional directions that resemble those of the most detailed paleomagnetic records. Excursions with opposite polarity directions recorded over less than 7.5 cm are barely detected in U‐channel measurements. Regarding reversals, U‐channel measurements smooth the signal of low‐resolution records and generate artificial transitional directions. Despite producing misleading similarities with the overall structure of transition records, longer transitional intervals fail also to reproduce the complexity of field changes. Finally, we test the convolution of magnetization by different response functions. The simulation reveals that even small response function changes can generate significant differences in results. -- Keywords : geomagnetic reversals ; geomagnetic excursions ; paleomagnetic measurements