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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
PubMed1999

Glycolytic potential of red, soft, exudative pork longissimus muscle.

Red, soft, exudative (RSE) pork is red as "normal" pork and exudative as PSE pork. The origin of RSE quality is unknown. In the present study, we determined whether the occurrence of RSE pork is related to the presence of the RN (Rendement Napole) gene. A glycolytic potential [= 2 x (glucose + glycogen + glucose-6-phosphate) + lactate] of > 180 micromol lactate/g of meat was used as indicator for presence of the RN gene. At 1 d postmortem, pork loin samples were collected at a commercial slaughter plant, and meat quality characteristics and glycolytic potential were determined. Glycolytic potential of RSE pork (n = 42) was higher (P < .01) than that of RFN (red, firm, nonexudative) pork (n = 25): 137 vs 110 micromol lactate/g of muscle. The glycolytic potential of PSE pork (n = 28) was 161 micromol lactate/g of muscle, which was higher (P < .01) than the glycolytic potential of RFN or RSE pork. Using a glycolytic potential of 180 micromol lactate/g of muscle as suggestive for the presence of the RN gene, four (10%) of the RSE samples were from RN carriers. By the same criterion, the PSE group contained nine (32%) RN gene carriers. These results suggest that the occurrence of RSE quality is not related to the presence of the RN gene.

Analysis of Variance↗
PubMed1999

Using pork to teach students quality variations and how they are measured. 1998 UW-AS-305 Class.

Using a total of eight pork loins representing DFD (dark, firm, and dry) and PSE (pale, soft, and exudative) conditions, 35 students conducted a series of objective and subjective measurements to demonstrate extremes in meat quality in a single 2-h laboratory. Students learned to objectively assess appearance, water-holding and water-binding capacity, ultimate pH (pHu), and shear force (cooked samples) by operating seven commonly known laboratory instruments. They also learned how to prepare and present samples for organoleptic analysis using hedonic and triangle tests. Finally, the students learned the factors related to meat quality and how extremely they can vary. Within one laboratory, they observed that DFD, when compared with PSE, averaged 1.5 units higher in pHu, 4.7% (absolute) less drip loss, bound 136% (absolute) more water, was darker in color (26 units lower L* value), was firmer with a more attractive structure requiring 1 kg/cm less force to shear, and was superior in organoleptic properties (overall 21% more desirable). Having 35 replicates to use for the data set, the results illustrated statistically significant variations in meat-quality traits and how they could be objectively measured. Nine months later, 12 of the students were surveyed. It was their perception that the laboratory was not any more effective than other laboratories in the same class, but they were able to remember 85% of the methods used to measure quality; about twice that of other methods taught in other laboratory sessions.

Animals↗
PubMed1998

Can pale, soft, exudative pork be prevented by postmortem sodium bicarbonate injection?

Previous attempts at eliminating the problem of PSE pork by genetic selection or rapid postmortem cooling have been only partially successful. A new approach, namely, postmortem injection of sodium bicarbonate (SBC), was tested on halothane-positive gilts. Sixteen pigs were used to establish a suitable SBC concentration. At approximately 15 min after death, the longissimus of one side of the carcass was injected with 10% (by weight) of .2 to .4 M SBC solutions containing .7% NaCl (wt/vol). All concentrations resulted in a higher ultimate pH, improved muscle color, and reduced drip loss. In a second experiment, with 23 pigs, .3 M SBC was injected into the longissimus and the biceps femoris at either 15 min or 24 h after death and with or without inclusion of .7% NaCl (wt/vol). Compared with controls, the 15-min SBC + NaCl injected samples had darker color (L* of 47 vs 53 in controls), higher ultimate pH (5.6 vs 5.3), lower drip loss (5% vs 10%), and increased protein solubility (140 vs 115 mg/g). Injection at 24 h reduced drip loss (from 10% to 5.7%) but did not correct the color defect. The SBC alone and SBC + NaCl treatments had essentially the same effects in reducing drip loss, increasing ultimate pH, and improving color; but the SBC-NaCl injected samples had improved juiciness and flavor compared with SBC. Early postmortem sodium bicarbonate injection seems to prevent the development of PSE pork when injected into carcasses of halothane-sensitive pigs.

Animals↗
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↗
PubMed1993

Pelvic growth, calf birth weight and dystocia in Holstein x Hereford heifers.

The pelvic area was measured in 129 Holstein x Hereford heifers at 10, 16 and 22 months of age. The heifers were fed an all forage diet. Pelvic growth was not linear over time, changing from an increase of 0.27 +/- 0.2 cm(2)/day during the first 6 months of the study to 0.13 +/- 0.13 cm(2)/day during the last 6 months (P<0.01). The relationship of pelvic area to body weight, height at hooks, and distance from hooks to pins did not change with age, and a moderate correlation between the pelvic area and these other measures (R=0.20 to 0.80) was noted. The pelvic area was measured within 24 hours after calving in 76 of the heifers. The rate of increase of pelvic area/day increased significantly (P < 0.01) in the month prior to calving from 0.14+/-0.13 cm(2) to 1.15 +/- 0.88 cm(2). As a result, the pelvic area at calving had a moderate correlation (R=0.29 to 0.52) to the pelvic area prior to calving. Logistic regression and discriminant analysis techniques were used to model the influence of the pelvic area and calf birth weight on the incidence of dystocia. Ratio of the pelvic area at calving to calf birth weight significantly (P < 0.01) influenced the incidence of dystocia. Logistic regression techniques were not superior to discriminant analysis; both correctly predicted 73% of the cases. Pelvic area measurement at any time other than calving was not associated with dystocia (P >0.05). Pelvic area and calf birth weight are important determinants of dystocia in heifers. The high degree of variation noted in pelvic growth, in particular during the month prior to calving, resulted in low correlation between pelvic area at calving and the precalving measurement. Therefore, we were not able to predict dystocia by measuring the pelvic area prior to calving.

Journal Article↗
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↗