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Biomedical subjects

R G Kauffman

Publications and source records attributed to R G Kauffman.

At least 19 recordsLinked to original sources
PubMed1997

Evaluation of electronic technology to assess lamb carcass composition.

Accurate price signals are essential for producers of American lamb to ensure production of uniformly lean animals. Development of carcass merit-pricing systems will require the use of objective technology for assessing carcass composition or lean distribution. The objective of this study was to evaluate electronic technologies for accurate determination of lamb carcass composition. Lambs (n = 106) were selected as a representation of U.S. market lambs that transcended geographic location, sex, breed, carcass weight, yield grade, and production system. The independent variables used to predict lamb composition varied with the technology. The electronic technologies tested included realtime ultrasound, optical reflectance probe, bioelectrical impedance analysis, and electromagnetic scanning (TOBEC). All technologies, except realtime ultrasound, were tested on warm (prerigor) carcasses and repeated after a 24-h chill. Longitudinal ultrasonic scans of fat and muscle tissue depth and grading probe fat depths were marginal predictors of proportional carcass yield. The TOBEC measurements often accounted for more variability associated with kilograms of dissected lean and percentage of carcass lean than did carcass weight. Equations from TOBEC measurements were the most accurate predictors of weight and percentage of dissected and fat-free lean. Bioelectrical impedance measurements of resistance and reactance combined with carcass weight were also good predictors of carcass composition. Prediction of carcass lean distribution by measures of TOBEC were the most accurate for prediction of leg lean. The implications of usefulness of these technologies will depend on the commitment of the U. S. sheep industry in development of a lamb price discovery system based on carcass composition.

Animals↗
PubMed1996

Assessment of lamb carcass composition from live animal measurement of bioelectrical impedance or ultrasonic tissue depths.

Market weight lambs, average weight 52.5 kg (+/-6.1), were used to evaluate nontraditional live animal measurements as predictors of carcass composition. The sample population (n = 106) represented U.S. market lambs and transcended geographic location, breed, carcass weight, yield grade, and production system. Realtime ultrasonic (RU) measurements and bioelectrical impedance analysis (BIA) were used for development and evaluation of prediction equations for % boneless, closely trimmed primal cuts (BCTPC), weight or % of dissected lean tissue (TDL), and chemically derived weight or % fat-free lean (FFL). Longitudinal ultrasonic images were obtained parallel to the longissimus thoracis et lumborum (LTL), positioning the last costae in the center of the transducer head. Images were saved and fat and LTL depths were derived from printed images of the ultrasonic scans. Bioelectrical impedance analysis was administered via a four-terminal impedance plethysmograph operating at 800 microA at 50 kHz. Impedance measurements of whole-body resistance and reactance were recorded. Prediction equations including common linear measurements of live weight, heart girth, hindsaddle length, and shoulder height were also evaluated. All measurements were taken just before slaughter. Bioelectrical impedance measurements (as compared to RU and linear measurements) provided equations for %BCTPC, TDL, %TDL, FFL and %FFL with the highest R2 and lowest root mean square error. Even though BIA provided the best equations of the three methodologies tested, prediction of proportional yield (%BCTPC, %TDL, and %FFL) was marginal (R2 = .296, .551, and .551, respectively). Equations combining BIA, RU, and linear measurements greatly improved equations for prediction of proportional lean yield.

Animals↗
PubMed1994

Electromagnetic scanning to predict lamb carcass composition.

The electromagnetic scanner generates a constant, low-level electromagnetic field (2.5 MHz) within a large plexiglass tube. The amount of electromagnetic (EM) energy transferred (to the carcass) is highly related to lean tissue. A plot of the absorption units over distance can be used to assess the total mass of lean tissue and of the respective primal cuts. The difference in curve height between two points (D), peak phase absorption, and linear carcass measurements (pre-rigor, HCWT or post-rigor, CWT carcass weight, and carcass length, LENG) were used to predict total dissected lean (TOTLEAN), dissected leg lean (LEGLEAN), and percentage of dissected carcass lean (PERLEAN). Twenty-one pre-rigor and 22 post-rigor (24 h chill) lamb carcasses, average weight 26.8 (+/- 4.2 kg) and 26.4 (+/- 4.1 kg) kg, respectively, were evaluated from measurements of total body electrical conductivity (TOBEC). Two geometric orientations were tested for statistical accuracy in this study: A) each carcass entered the EM tunnel rear leg first, on its left lateral side, neck facing the right side of the tunnel; and B) each carcass entered the EM tunnel rear leg first, breast down, and neck up. Orientation A proved more statistically efficient for pre-rigor carcasses, and orientation B was more desirable for post-rigor carcasses. Multiple-regression models involving HCWT, LENG, and a single D measure accounted for 98.0 and 95.0%, respectively, of the total variation in pre-rigor carcass TOTLEAN and LEGLEAN in A.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Modernizing the animal science curriculum: is change needed?

To identify an animal science curriculum is difficult because it is a "moving target" due to changing needs and demands of our society and, more specifically, to changes in the backgrounds and interests of students. Therefore, animal science curriculums not only should change, but must change, if they are to succeed. With new technological innovations and discoveries that either modify, supplement, or change basic concepts and approaches, it is paramount that changes in courses as well as in the curriculum conform. Because of the applied nature of animal science and because of the many unknowns yet to be discovered, the curriculum should be under continual scrutiny. However, we must not fix something when it is not broken. For all practical purposes, a curriculum reflects a philosophy of what subjects should be included to complete a plan of study. After a philosophy has been established the base curriculum will seldom change significantly. When it does, it will be the result of a change in people's philosophies rather than a reflection of industry needs or student interests. Teachers should not forget how to teach most effectively the material and must never lose sight of their goal of molding students into knowledgeable, wise, and responsible citizens in our society.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Husbandry↗
PubMed1986

The histology of developing porcine adipose tissue.

At each of the following days after conception (45, 60, 75, 90 and 105), pig fetuses were removed from sows representing lean and fat stains. From two additional litters, postnatal pigs were sacrificed at 1, 3, 6, 9, 12, 15, 18 and 21 d. Pelikan dye was injected into fetuses and pigs. The whole of the dorsal subcutaneous tissue, including some underlying muscle, was removed. Tissue was fixed into paraffin blocks or was frozen. Paraffin and frozen sections were stained and examined for stromal-vascular and cellular changes during growth. Organized stromal-vascular changes occurred during a period of adipocyte formation from 45 d gestation until 9 d postnatally. At 45 d gestation, the subcutaneous tissue contained many short unorganized connective tissue fibers. Gradually, these fibers became more organized in a ventral to dorsal and caudal to cranial gradient, so that by 1 d postnatally, they formed complete lobules around all existing fat cell clusters. The presumptive adipose space of the complete lobules contained delicate strands of connective tissue and reacted metachromatically for mucin. Connective tissue around lobules became progressively thinner throughout the remaining postnatal ages. Vascularity of the subcutaneous tissue increased as the stromal became organized. Lipid was not present in the subcutaneous tissue at 45 d gestation, but some deposition was apparent in the inner layer at 60 d. Between 60 d gestation and 9 d postnatally, fat cells filled both subcutaneous layers in a ventral to dorsal formation. Presumptive adipose lobules were the source of adipocytes and capillaries of developing fat cell clusters. Adipocytes from fetuses through 1-d postnatal pigs were multilocular, while unilocular fat cells were first observed at 3 d. At 9 d, multilocular adipocytes were found singly or in groups within unilocular fat cell lobules.

Adipose Tissue↗
PubMed1986

Mitotic activity in fetal and early postnatal porcine adipose tissue.

Tritiated thymidine autoradiography and histochemistry were used to study the development of subcutaneous adipose tissue of lean and obese fetuses and postnatal pigs. A pattern of tritiated thymidine uptake by pre-adipocytes and adipocyte lipid accumulation was demonstrated during the growth of the fetal pig. In the youngest fetuses there was a period of intense stromal cell mitotic activity before any adipocyte lipid accumulation. During subsequent fetal development, clusters of tightly arranged stromal cells were formed. Lipid accumulation occurred only in these cell clusters. During this time of cell cluster formation and lipid accumulation, mitotic activity was minimal. In obese fetuses, stromal cell mitotic activity overlapped temporarily with the cell cluster formation and lipid accumulation period. In early postnatal pigs, fat cell clusters increased in size until they "physically filled" the adipose tissue. In pigs 3 d and older, there was extensive mitotic activity of cells within the fat cell clusters. The synthesis of this second bed of pre-adipocytes and the altered developmental pattern in the obese fetuses is suggested to be due to the influence of a high fat diet. The significance of these findings in terms of plausible links between pre-adipocyte mitosis and lipid accumulation is discussed.

Adipose Tissue↗
PubMed1981

Biological detection of heterozygosity for double muscling in cattle. I. Terminal innervation ratio.

The extent of axonal branching of peripheral motor nerves in musculature of homozygous and heterozygous double-muscled cattle and of nondouble-muscled cattle was investigated. The purpose was to determine whether there are differences between genotypes and if such differences could be useful as objective criteria for identifying heterozygotes. Significant differences were found between the functional terminal innervation ratios for double-muscled and nondouble-muscled groups for both the semitendinosus and semimembranosus muscles. However, there was considerable overlap among individual animals of different genotypes. Because of this overlap, and the possibility that axonal branching may be related to the degree of muscle enlargement, we concluded that terminal innervation ratios would be of marginal value in identifying double-muscled heterozygotes.

Animals↗
PubMed1981

Biological detection of heterozygosity for double muscling in cattle. II. Thyroid hormone concentrations.

Serum levels of triiodothyronine and thyroxine were measured by radioimmunoassay to determine whether differences exist between double-muscled (DM) homozygous, DM heterozygous and non-DM cattle of beef and dairy origins. No differences in triiodothyronine concentrations were found between heterozygous and non-DM beef animals, but thyroxine concentrations in non-DM dairy cattle were significantly different from those in non-DM beef. Unexpectedly, hormone concentrations in DM homozygotes were lower than those in other genotypes.

Animals↗
PubMed1973

Cellular and enzymatic changes in porcine adipose tissue during growth.

Experiments were designed to define some of the cellular and metabolic changes in various areas of porcine adipose tissue during growth and to establish a relationship between these changes and the accumulation of fat in the domestic pig. 35 male castrate pigs were killed at various ages from late fetal to 6.5 months. The following determinations were made on each animal: (1) total carcass fat, (2) adipose cell size and number by fixation of adipose tissue with osmium tetroxide, and (3) the activities of acetyl CoA carboxylase, citrate cleavage enzyme, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, and malic enzyme from perirenal adipose tissue and each of the three layers of subcutaneous backfat. Carcass adipose tissue expanded by a combination of adipocyte hyperplasia and hypertrophy up to 5 months, after which adipose expansion was accomplished by cellular hypertrophy only, with no significant increase in cell number. The activities of the selected lipogenic enzymes (expressed on an adipose cell basis) increased markedly at weaning and again during the rapid increase in percentage of body fat between 3.5 and 5 months. Enzyme activities reached a peak at 5 months, after which activities decreased to values approaching mature levels.

ATP Citrate (pro-S)-Lyase↗
PubMed1972

Lipogenic enzyme activities and cellularity of porcine adipose tissue from various anatomical locations.

The activities of acetyl CoA carboxylase, citrate cleavage enzyme, malic enzyme, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase were determined in porcine adipose tissue samples taken from seven anatomical locations, including three layers of backfat, intermuscular, perirenal, mesenteric, and leg subcutaneous adipose tissues. Adipocyte size and number, as well as lipid and soluble protein content, were also measured in order to establish some of the differences that exist between different areas of porcine adipose tissue. It was found that adipose tissue from areas where fat is deposited very readily (particularly the perirenal region) had higher enzyme activities, larger adipose cells, a lesser amount of stromal tissue, a greater amount of ether-extractable lipid, and a lower concentration of adipose cells per gram of tissue than samples from areas where fat is deposited only sparsely (leg subcutaneous).

Adipose Tissue↗