Surgery – Diagnostic testing – Liquid collection
Reexamination Certificate
2000-06-09
2003-03-18
Shaver, Kevin (Department: 3736)
Surgery
Diagnostic testing
Liquid collection
C600S581000, C119S174000
Reexamination Certificate
active
06533734
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The invention relates to fluid sampling in living creatures. Particularly, the invention relates to sampling of fluid from the rumens of cattle, sheep, or goats.
BACKGROUND OF THE INVENTION
Unlike nonruminants (e.g., horses, poultry and swine), ruminants (e.g., cattle, goats and sheep) have a four-compartment stomach. The rumen is the largest compartment and functions as a large fermentation chamber, in which microbes produce volatile fatty acids. These are then absorbed and used by the animal for productive purposes (e.g., milk production and growth). The importance of volatile fatty acids to animal-productivity has resulted in the development of frequent and labor-intensive sampling methods for their determination.
Researchers, large feed companies, and some private laboratories devote considerable resources to measuring the effects of various feeds and feed treatments on ruminal fermentation. The pattern of fermentation in the rumen must be closely monitored using some sort of sampling apparatus to properly determine the nutritional value of diets. Fermentation in the rumen [e.g., the production of volatile fatty acids (acetic, propionic, butyric, and higher acids)] is a dynamic process and a major determinant of the efficiency of animal growth, milk production, and milk composition.
Ruminal sampling methods also are important in veterinary practice. These techniques are responsible for assisting in the diagnosis of digestive diseases and latent or clinical conditions affecting digestion and the well-being of the animal. A critical factor limiting our ability to gather data about ruminal fermentation has been the lack of appropriate sampling methods.
Several factors complicate ruminal sampling; however, most arise from the heterogeneous nature of the ruminal contents and the dynamics of the digestion process. A sample representative of the biological and biochemical environment of the rumen is best collected under standard conditions in relation to time of feeding and location in the rumen, preferably from the center or ventral ruminal sac. Ruminal fluid samples should also be taken over time to account for diurnal changes.
Conventional methods of collecting ruminal fluid may not produce representative samples in terms of quality and quantity, while methods able to provide representative samples are often impractical. The various approaches currently used to obtain samples of ruminal fluid are:
A. Slaughter
1. Description
Digesta fluid samples have been obtained at slaughter for many years [e.g., Ulyatt, M. J. et al. 1984. Effect of intake and feeding frequency behavior and quantitative aspects of digestion in sheep fed chaffed lucerne hay. J. Agr. Sci. (Camb.): 102:645]. The technique has proved most useful for sampling digesta fluid in wild animals, although occasionally it has been employed in agricultural studies.
2. Problems
a. The main disadvantage of sampling at slaughter is that only single samples are obtained. Rarely does such a sampling scheme fit into current experiments on valuable livestock or endangered animals. It has been used recently only in very intensive experiments with few animals. Even more rarely is it used with wild animals.
b. Standard technique also requires that feed be withheld from animals for some interval before slaughter. This artificial situation makes the samples obtained less valuable. Special arrangements have sometimes been made at slaughter to allow rapid sampling after exsanguination.
c. Digestion is dynamic; therefore, several samples should be collected over the day to adequately describe the process. This problem has been handled by slaughtering groups of animals at various times after feeding; however, it is obviously a costly and time-consuming approach.
B. Stomach Tube
1. Description
In this technique, digesta fluid samples are obtained by aspiration through a tube passed through a speculum in the mouth and via the esophagus to the reticulorumen of intact animals (e.g., Geishauser, T., and A. Gitzel. 1996. A comparison of rumen fluid sampled by ororuminal probe versus rumen fistula. Small Ruminant Res. 21:63; and Dirksen, G., and M. C. Smith. 1987. Acquisition and analysis of bovine rumen fluid. Bovine Pract. 22:108).
2. Problems
a. A major problem with this technique is that the fluid samples obtained are often contaminated with variable quantities of saliva and mucus. Some have tried to reduce the problem by discarding the first part of the sample obtained by aspiration.
b. The position of the sampling tube in the reticulorumen is unknown during sampling. The composition of spot samples from various locations in the reticulorumen often differs; therefore, it is unlikely that fluid samples via a stomach tube are representative of the overall environment in the reticulorumen.
This problem has been handled by focusing on differences between treatments so that the results obtained are not considered quantitative measures of the overall environment in the reticulorumen.
c. Animals must be disturbed and additional restraint applied to effectively sample with this method. This is especially problematic when repeated sampling is required. This problem has been handled by avoiding repeated sampling and developing skilled handlers who can obtain samples while minimizing disturbance of the animal.
d. Repeated sampling increases the labor required to obtain samples. This drawback has been recognized by all who have been involved in 24-hour sampling protocols. It is usually handled by enlisting groups of people to cooperate during sampling periods.
e. The sampling tube is often plugged when vacuum is applied because large digesta particles occlude the holes through which fluid would otherwise move. This problem occurs frequently and is usually overcome by sliding the sampling tube in and out to scrape off particles blocking the holes.
C. Naso-ruminal Sampler
1. Description
A naso-ruminal sampler obtains digesta fluid by aspiration through an indwelling tube passed through the nose and pharynx and then via the esophagus to the recitulorumen of intact animals [e.g., Poulsen, S. D. et al. 1988. Clinical chemical comparative examination or ruminal samples collected by means of a naso-ruminal sampler. Acta. Vet. Scand. 29:129; and Moloney, A. P. 1997. Comparison of procedures for the collection of rumen fluid from cattle. Irish J. Ag. Fd. Res. 36(Suppl. 1): 108 (Abstr.)].
2. Problems
a. Naso-rumen samples of digesta fluid would not be representative of the overall environment of the reticulorumen, because fluid is obtained from a single but unknown location. As with the samples obtained using a stomach tube, the problem has been handled by focusing on differences between treatments so that the results obtained are not considered quantitative measures of the overall environment in the reticulorumen.
b. Animals must be disturbed and additional restraint applied to effectively sample with this method. This is especially problematic when repeated sampling is required. This problem has been handled by avoiding repeated sampling and developing skilled handlers who can obtain samples while minimizing disturbance of the animal.
c. Repeated sampling increases the labor required to obtain samples. This drawback has been recognized by all who have been involved in 24-hour sampling protocols. It is usually handled by enlisting groups of people to cooperated during sampling periods.
d. The sampling tube is often plugged when vacuum is applied because large digesta particles occlude the holes through which fluid would otherwise move. This problem occurs frequently and is usually overcome by sliding the sampling tube in and out to scrape off particles blocking the holes.
D. Spot Sampler
1. Description
This technique utilizes an evacuated flask to obtain composite samples of digesta fluid from several sites via a perforated tube in cannulated animals (e.g., Woodford, S. T., and M. R. Murphy. 1988. Dietary alteration of particle breakdown and passage from the rumen in lactating diary cattle. J. Da
Corley, III Robert N.
Murphy Michael R.
Panno Samuel V.
Marmor II Charles
Polit & Associates, LLC
Shaver Kevin
The Board of Trustees of the University of Illinois
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