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Biomedical subjects

L B Hansen

Publications and source records attributed to L B Hansen.

At least 19 recordsLinked to original sources
PubMed2006

Production of pure Holsteins versus crossbreds of Holstein with Normande, Montbeliarde, and Scandinavian Red.

Pure Holsteins (n = 380) were compared to Normande/Holstein crossbreds (n = 245), Montbeliarde/Holstein crossbreds (n = 494), and Scandinavian Red/Holstein crossbreds (n = 328) for 305-d milk, fat, and protein production during first lactation. Scandinavian Red was a mixture of Swedish Red and Norwegian Red. Cows were housed at 7 commercial dairies in California and calved from June 2002 to January 2005. All Holstein sires and all Holstein maternal grandsires were required to have a code assigned by the National Association of Animal Breeders to assure they were sired by artificial insemination bulls. Daughters of Normande, Montbeliarde, and Scandinavian Red sires were artificial insemination bulls via imported semen. Best prediction was used to calculate actual production (milk, fat, and protein) for 305-d lactations. Adjustment was made for age at calving and milking frequency, and records less than 305 d were projected to 305 d. Herd-year-season (4-mo seasons) and the genetic level of each cow's Holstein maternal grandsire were included in the model for statistical analysis. Pure Holsteins had significantly higher milk (9,757 kg) and protein (305 kg) production than all crossbred groups, but pure Holsteins (346 kg) were not significantly different from Scandinavian Red/Holstein (340 kg) crossbreds for fat production. Fat plus protein production was used to gauge the overall productivity of pure Holsteins vs. crossbreds. The Scandinavian Red/Holstein (637 kg) crossbreds were not significantly different from the pure Holstein (651 kg) for fat plus protein production; however, the Normande/Holstein (596 kg) and the Montbeliarde/Holstein crossbreds (627 kg) had significantly lower fat plus protein production than pure Holsteins.

Animals↗
PubMed2006

Calving difficulty and stillbirths of pure Holsteins versus crossbreds of Holstein with Normande, Montbeliarde, and Scandinavian Red.

Pure Holstein cows and Normande/Holstein, Montbeliarde/Holstein, and Scandinavian Red/Holstein crossbred cows were compared for calving difficulty and stillbirth rates. Scandinavian Red was a combination of Norwegian Red and Swedish Red. All cows calved from June 2001 to August 2004 at 7 commercial dairies. Statistical models for analysis included effects of herd-year-season of calving and sex of calf in addition to breed of sire and breed group of dam. Male calves had significantly more calving difficulty and stillbirths than heifer calves. First-calf Holsteins bred to Holstein, Brown Swiss, Montbeliarde, and Scandinavian Red bulls were used to determine effects of breed of sire. Calves sired by Scandinavian Red bulls (5.5%) and Brown Swiss bulls (12.5%) had significantly less calving difficulty than calves sired by Holstein bulls (16.4%) from Holstein first-calf heifers. Also, fewer stillbirths resulted from use of Scandinavian Red bulls (7.7%) compared with use of Holstein bulls (15.1%) for first-calf Holstein heifers. Scandinavian Red-sired calves (2.1%) had significantly less calving difficulty than Holstein-sired calves (8.4%) for multiparous Holstein dams. Non-Holstein breeds of sire had significantly fewer stillbirths than Holstein sires when mated to multiparous Holstein dams. To determine the effects of breed of dam, 676 pure Holsteins, 262 Normande/Holstein, 370 Montbeliarde/Holstein, and 264 Scandinavian Red/Holstein crossbred virgin heifers that had been bred to Brown Swiss, Montbeliarde, and Scandinavian Red bulls were utilized. All groups of crossbred cows had significantly less calving difficulty at first calving than pure Holsteins (3.7 to 11.6% vs. 17.7%). Furthermore, Montbeliarde/Holstein (6.2%) and Scandinavian Red/Holstein (5.1%) crossbreds had significantly lower stillbirth rates at first calving than pure Holsteins (14.0%).

Animals↗
PubMed2006

Fertility and survival of pure Holsteins versus crossbreds of Holstein with Normande, Montbeliarde, and Scandinavian Red.

First-calf pure Holsteins and Normande/Holstein, Montbeliarde/Holstein, and Scandinavian Red/Holstein crossbreds were compared for days to first breeding, first-service conception rate, days open, and survival. First-calf heifers were in 7 commercial dairies in California and calved from June 2002 to October 2004. Holsteins were required to have a recorded sire with a National Association of American Breeders code to assure they were sired by artificially inseminated bulls. Normande-, Montbeliarde-, and Scandinavian Red-sired crossbreds were all daughters of artificially inseminated bulls via imported semen. For days open, first-calf heifers were required to be at least 250 d in milk and those with greater than 250 d open were truncated to 250 d. Least squares means for days to first breeding were 69 d for Holsteins, 62 d for Normande/Holstein, 65 d for Montbeliarde/Holstein, and 66 d for Scandinavian Red/Holstein crossbreds, and differed significantly from pure Holsteins for Normande/Holstein and Montbeliarde/Holstein crossbreds. First-service conception rates were 22% for Holsteins, 35% for Normande/Holstein, 31% for Montbeliarde/Holstein, and 30% for Scandinavian Red/Holstein crossbreds and, again, differences from Holstein were significant for the Normande/Holstein and Montbeliarde/Holstein crossbreds. Least squares means for days open were 150 +/- 4.1 d for pure Holsteins, 123 +/- 3.8 d for Normande/Holstein, 131 +/- 4.4 d for Montbeliarde/Holstein, and 129 +/- 4.6 d for Scandinavian Red/Holstein crossbreds, and all 3 cross-bred groups had significantly fewer days open than pure Holsteins. Three measures of survival were to 30, 150, and 305 d postpartum, and all crossbred groups survived significantly longer than pure Holsteins during first lactation for all 3 measures of survival. Least squares means for survival to 30 d postpartum were significantly different for pure Holsteins (95%) vs. all crossbred groups (98%), were significantly different for survival to 150 d postpartum for pure Holsteins (91%) vs. all crossbred groups (96%), and were significantly different for survival to 305 d postpartum for pure Holsteins (86%) vs. all crossbred groups (92 or 93%).

Animals↗
PubMed2005

Drugs in injured drivers in Denmark.

As part of the project Impaired Motorists, Methods of Roadside Testing and Assessment for Licensing (IMMORTAL) under the European Commission's Transport RTD Programme of the 5th Framework Programme [I.M. Bernhoft, Drugs in accidents involved drivers in Denmark, D-R4.3 of the project Impaired Motorists, Methods Of Roadside Testing and Assessment for Licensing (IMMORTAL), , 2005], a study regarding drugs in accident-involved drivers was carried out in Denmark. The main objectives of this study were: (1) to collect and analyse samples from injured drivers for the presence of drugs; (2) to give an indication whether drugs may have contributed to traffic accidents; and (3) to get information on the drug-positive drivers and their drug use. This paper focuses on objective 1. Injured drivers who were treated in hospital were asked to give a saliva sample, a blood sample or both. The samples were screened for the following substances: opiates, amphetamines, methamphetamines, incl. MDMA (ecstasy), cannabinoids and metabolites, cocaine and metabolites and benzodiazepines. Screenings were carried out by means of Cozart Microplate EIA kit. Positive screenings were confirmation analysed by gas chromatography-mass spectrometry (GC-MS) or liquid chromatography/tandem mass spectrometry (LC/MS/MS). In total, 26 out of 330 patients were confirmed positive for one or more of the six drug groups. However, three patients were excluded from the survey for various reasons. Of the remaining 23 drug-positive patients 15 were found positive for one drug group, and in five of these cases alcohol was present in a concentration over the legal limit in Denmark (0.05%). The other eight patients were found positive for two drug groups, and in four of these cases, alcohol was also present in a concentration over the legal limit. Alcohol was found both in combinations with medicinal drugs, with illegal drugs and with both. Based on the saliva or blood concentrations, we estimate that there is a strong suspicion of impairment in 9 out of 23 cases, and in another six cases it was likely that the drivers were impaired.

Accidents, Traffic↗
PubMed2005

Partly occupied Wannier functions.

We introduce a scheme for constructing partly occupied, maximally localized Wannier functions (WFs) for both molecular and periodic systems. Compared to the traditional occupied WFs the partly occupied WFs possess improved symmetry and localization properties achieved through a bonding-antibonding closing procedure. We demonstrate the equivalence between bonding-antibonding closure and the minimization of the average spread of the WFs in the case of a benzene molecule and a linear chain of Pt atoms. The general applicability of the method is demonstrated through the calculation of WFs for a metallic system with an impurity: a Pt wire with a hydrogen molecular bridge.

Journal Article↗
PubMed2005

Growth hormone response to growth hormone releasing hormone in calves that differ in genetic merit for milk yield.

Holstein heifer, steer, and bull calves from control (CL) and select (SL) lines of cows that differed by more than 4000 kg of milk during a 305-d lactation (SL > CL) were used to determine growth hormone (GH) response to 5 doses of GH releasing hormone (GHRH) and how this response was affected by gender, period (age), and genetic merit for milk yield. Doses (0, 2.5, 5, 10, and 20 microg/100 kg of BW) of a GHRH analog were assigned randomly to each heifer (4 CL, 4 SL), steer (4 CL, 4 SL), and bull (3 CL, 3 SL) calf and administered on consecutive days at approximately 3, 6, and 10 mo of age (periods; P1, P2, and P3). Jugular blood samples (n = 15) collected between -30 and 240 min relative to GHRH administration were used to quantify area under the GH response curve (AUC) after subtracting mean prechallenge GH concentrations. Estimates of maximum response (Rmax) and sensitivity (ED50) to GHRH were obtained from the hyperbolic dose response curves (AUC vs. dose). Data were analyzed for effects of dose, line, period, gender, and their interactions with period as the repeated effect. Prechallenge GH concentrations were not affected by genetic line, gender, or period. The AUC was not affected by line, but decreased with period and increased with GHRH dose. The Rmax did not differ between lines or among genders, but decreased with period. The ED50 did not differ between lines or among periods, but heifers were more sensitive to GHRH than steers or bulls. Although GH response to GHRH has been identified as a potential indicator of genetic merit, it did not differ between these substantially different genetic lines.

Aging↗
PubMed2005

Effects of week of lactation and genetic selection for milk yield on milk fatty acid composition in Holstein cows.

Control (CL) and select line (SL) dairy cows (n = 22) managed identically but differing in milk yield (>4100 kg/305 d) were used to determine differences in milk fatty acid profile as lactation progressed. Milk yield was recorded daily and milk samples were collected during wk 1, 4, 8, 12, and 16 postpartum for milk composition analysis. Milk samples from wk 1, 8, and 16 were also analyzed for fatty acid composition. Select-line cows produced more milk (44.4 vs. 31.2 kg/d) and milk components than CL cows during the 16-wk period. There was no difference in rate of milk yield increase, but peak milk yield for SL cows was greater and occurred later in lactation. There were no differences in milk SCC or milk fat, protein, or lactose content. Selection for milk yield did not affect the content of most individual milk fatty acids; however, compared with CL, SL cows had a reduced Delta(9)-desaturase system and tended to produce milk with lower monounsaturated fatty acid content. Selection for milk yield did not affect milk fatty acid origin but the percentage of de novo fatty acids increased and preformed fatty acids decreased as lactation progressed. Milk fat trans-11 18:1 and cis-9,trans-11 conjugated linoleic acid increased with progressing lactation (10.7 vs. 14.1 and 3.1 vs. 5.4 mg/g, or 31 and 76%, respectively) and were correlated strongly among wk 1, 8, and 16 of lactation. Temporal changes in the Delta(9)-desaturase system occurred during lactation but these changes were not correlated with milk fat cis-9,trans-11 conjugated linoleic acid content. Results indicate prolonged genetic selection for milk yield had little effect on milk fatty acid composition, but milk fatty acid profiles varied markedly by week of lactation.

Animals↗
PubMed2003

Progressive introgression between Brassica napus (oilseed rape) and B. rapa.

We have earlier shown extensive introgression between oilseed rape (Brassica napus) and B. rapa in a weedy population using AFLP markers specific for the nuclear genomes. In order to describe the progress of this introgression, we examined 117 offspring from 12 maternal plants from the introgressed population with the same AFLP-markers; AFLP data were supported by chromosome counting. We also analysed the offspring with a species-specific chloroplast marker and finally evaluated the reproductive system in selected maternal plants. Our results indicated a high outcrossing rate of the introgressed maternal plants. It seemed that B. rapa most often functioned as the maternal plant in the introgression process and that the amount of oilseed rape DNA was highly diminished in the offspring compared to their introgressed maternal plants. However, our analysis of plants from the weedy population indicated that introgression can lead to both (1) exchange of chloroplast DNA between species producing B. rapa-like plants with B. napus chloroplasts and (2) incorporation of B. napus C-genome DNA into the B. rapa genome. Therefore, we question whether it can be regarded as containment to position transgenes in the chloroplast or in specific parts of the nuclear genome of B. napus.

Brassica napus↗
PubMed2002

Matrix metalloproteinase inhibition impairs adipose tissue development in mice.

The effect of galardin, a broad-spectrum matrix metalloproteinase (MMP) inhibitor, was studied in mice kept on a high fat diet (HFD). Five-week-old male wild-type mice were fed the HFD (42% fat) for up to 12 weeks and were daily injected intraperitoneally with the inhibitor (100 mg/kg) or with vehicle. After 12 weeks of the HFD, the body weights of both groups were comparable, but the weight of the isolated subcutaneous (SC) or gonadal (GON) fat deposits was significantly lower in the inhibitor-treated group than in the control group (88 +/- 11 versus 251 +/- 66 mg, respectively, for SC fat [P<0.05]; 90 +/- 24 versus 217 +/- 30 mg, respectively, for GON fat [P<0.02]). The number of adipocytes was somewhat higher and the diameter was somewhat smaller (but not significantly) in adipose tissues of the inhibitor-treated group. Adipose tissue of the inhibitor-treated mice contained more collagen than did that of the vehicle-treated mice (Sirius red-stained area of 42 +/- 2.6% versus 22 +/- 4.4%, respectively, for SC fat [P<0.05]; 21 +/- 5.1% versus 4.7 +/- 0.92%, respectively, for GON fat [P<0.01]); a distinct collagen-rich cap was formed around the inhibitor-treated tissue. In situ zymography with casein- or gelatin-containing gels confirmed a reduced MMP activity in SC and GON adipose tissues of inhibitor-treated mice. Thus, in this model, growth and development of adipose tissue appears to be limited by the formation of a collagen-rich matrix cap around the inhibitor-treated tissue. These data suggest a functional role for MMPs in the development of adipose tissue.

Adipocytes↗
PubMed2002

LDL receptor mutation genotype and vascular disease phenotype in heterozygous familial hypercholesterolaemia.

Patients with homozygous familial hypercholesterolaemia (FH) caused by receptor-negative, low-density lipoprotein (LDL) receptor gene mutations have higher concentrations of LDL-cholesterol in plasma and earlier onset of cardiovascular disease (CVD) than patients homozygous for receptor-defective, LDL receptor mutations. In contrast, it is uncertain whether the severity of atherosclerotic disease differs in heterozygous FH caused by receptor-negative and receptor-defective mutations. The present authors investigated the influence of LDL receptor mutation type on the clinical phenotype in 31 patients with heterozygous FH caused by the receptor-negative, Trp23-stop mutation and in 31 patients heterozygous for the receptor defective Trp66-Gly mutation. Untreated levels of plasma LDL-cholesterol and calculated cholesterol-years score did not differ significantly between the two groups of patients. Detection of vascular disease was based on two approaches: (1) measurement of coronary calcification by spiral computed tomography (CT) scanning; and (2) ultrasonic measurement of carotid intima-media thickness (IMT). Age was significantly correlated to the presence of coronary calcification, but controlling for relevant cofactors, there was no evidence that the receptor-negative mutation caused more calcification than the receptor-defective mutation. Furthermore, carotid IMT was significantly influenced by plasma concentrations of Lp(a) and triglycerides, as well as by age, sex and smoking status, but again, there was no statistically significant effect of LDL receptor gene mutational type. The similarity in vascular phenotypes was probably caused by a similar life-long burden of LDL-cholesterol in the two groups of patients.

Adult↗
PubMed2002

Effects of selection for milk yield on growth hormone response to growth hormone releasing factor in growing Holstein calves.

Bull and heifer calves (n = 81) from genetic lines of Holstein cows that differed by more than 4000 kg milk/305-d lactation were used to determine effects of selection for milk yield on growth hormone (GH) response to a GH releasing factor (GRF) analog. Calves received GRF (4 microg/100 kg BW) on 10, 56, 140, 196, 252, and 364 +/- 3 d of age. Jugular blood samples (n = 15) were obtained from -30 to 120 min relative to GRF administration. Area under the GH response curve (0 to 60 min, AUC60) was quantified after subtracting mean prechallenge GH concentrations. Data were analyzed for effects of line, age, gender, and their interactions with PROC MIXED of SAS for repeated measures and incorporated the spatial power law for unequally spaced data with age as the repeated effect. Means were considered different when P < 0.05. Prechallenge GH concentrations did not differ between lines, were greater in bulls than heifers (4.6 vs. 3.7 ng/ml), and decreased with age. The AUC60 decreased with age but did not differ between lines. Heifers responded more to GRF than bulls (1550 vs. 1336 ng x min/ml). Peak GH concentration decreased with age and was less in bulls than heifers (54.7 vs. 62.1 ng/ml) but did not differ between lines. Although plasma GH has been identified as an inheritable trait, we conclude the GH variables measured in this study were not useful in predicting genetic merit of calves from these substantially different lines of cows.

Aging↗
PubMed2001

A stable gas chromatography-mass spectrometry analysis system to characterize Ma Huang products found in health foods and supplements.

Herbal mixtures containing Ma Huang are of significant interest because of their popularity regardless of their potential health hazards. In spite of reports of health problems and even several deaths, these products are still frequently recommended for use. The complex nature of the commercial supplement mixtures has posed a problem in both their qualitative and quantitative analysis. A gas chromatographic procedure has been developed to evaluate authenticity of Ma Huang mixtures. Mass spectrometric identification of the six major alkaloid ephedrine components and application of chi-square evaluation of the chromatographic profile allows a determination to be made regarding the nature of the origin of the mixture. For comparison, a standard mixture was prepared that approximates a typical Ma Huang composition based on average amounts of each alkaloid component reported in the literature. The system is temperature stable and allows simultaneous analysis for caffeine and other components of the commercial supplements. Several samples of commercial herbal products were analyzed by the procedure, and their composition is evaluated and discussed.

Dietary Supplements↗
PubMed2001

Heritability of teat-end shape and the relationship of teat-end shape with somatic cell score for an experimental herd of cows.

Teat-end shapes were categorized for 1443 Holstein cows with 3582 lactations, in the Iowa State University herd at Ankeny, approximately 40 d postpartum between 1970 and 1995. Frequencies of teat-end shapes were as follows: round, 52.2%; prolapsed, 0.8%; flat, 14.2%; plate, 3.4%; funnel, 8.9%; and mixed, 20.5%. Cows were coded as mixed if all four teat-end shapes were not the same. Heritability estimates were obtained with an animal model with pedigrees traced back to registration numbers roughly conforming to birth year 1955. The heritability estimates for first, second, and third and later lactations were 34, 21, and 13%, respectively. Lactation averages for linear somatic cell scores were adjusted for days in milk, and month and age at calving, and were available for 255 cows with 431 lactations categorized from 1992 to 1995. Frequencies of teat-end shape on the 255 cows were as follows: round, 58%; prolapsed, 3%; flat, 11%; plate, 2%; funnel, 6%; and mixed, 20%. Least-squares means of somatic cell score for categories of teat-end shape were computed from a mixed model that included year, parity, and teat-end shape as fixed effects and cow as a random effect. Teat-end shape did not significantly affect somatic cell score.

Animals↗
PubMed2000

Determination of ascorbigens in autolysates of various Brassica species using supercritical fluid chromatography.

A new method of analysis based on normal phase supercritical fluid chromatography (SFC) has been developed for investigation of ascorbigens [2-C-(indol-3-ylmethyl)-beta-L-xylo-3-hexulofuranosonic acid gamma-lactone derivatives]. This method has been adapted to preparative isolation and quantitative determinations of individual ascorbigens comprising ascorbigen, neoascorbigen, and 4-methoxyascorbigen. The structures of these compounds have been revealed from 1D ((1)H, (13)C) and 2D (COSY, HMQC, HMBC) NMR experiments. The developed SFC method had an acceptable linearity for the ascorbigens with correlation coefficients (R(2)) > 0.9995 (n = 10) in the range of 0.13-4.9 nmol injected, detection limits were below 13 pmol, retention time stabilities were excellent, and relative response factors have been determined. The SFC method has been used for determination of ascorbigens produced during autolysis of indol-3-ylmethylglucosinolates in various Brassica vegetables and rapeseed seedlings. Generally, 30-60% of the indol-3-ylmethylglucosinolates in the plants were transformed into ascorbigens, with the concentration in autolysates varying from 0.51 +/- 0.002 to 3.72 +/- 0.21 micromol/g of dry weight (DW) for ascorbigen, from 0.05 +/- 0.01 to 2.42 +/- 0.23 micromol/g of DW for neoascorbigen, and from 0.03 +/- 0.002 to 0.84 +/- 0.07 micromol/g of DW for 4-methoxyascorbigen.

Ascorbic Acid↗
PubMed2000

Consequences of selection for milk yield from a geneticist's viewpoint.

The annual genetic trend for milk yield of Holsteins in the United States has accelerated with time and had means of 37 kg during the 1960s, 79 kg during the 1970s, 102 kg during the 1980s, and 116 kg from 1990 to 1996. Selection programs of the dairy cattle breeding firms in the United States have become more selective and effective with time, and selection goals continue to place major emphasis on yield traits, which clearly impact profitability of dairying. Traits other than yield are also included in selection goals of the industry. Type traits, especially those related to udder conformation, body size, and angularity have been included in selection programs and have altered the appearance and physiological functions of Holstein cows. Selection programs have continued to increase the body size of Holsteins despite mounting evidence that smaller cows have advantages for survival and efficiency. Favorable emphasis on cows that appear sharper might result in cows that are more prone to metabolic problems. The high intensity of current selection in the United States has brought about a rapid increase in genetic relationships among animals. Increased relationships will inevitably result in undesirable levels of inbreeding in the commercial cow population unless dairy producers turn to crossbreeding.

Animals↗
PubMed2000

Heritability of clinical mastitis incidence and relationships with sire transmitting abilities for somatic cell score, udder type traits, productive life, and protein yield.

The objective of this study was to determine the relationships among daughter clinical mastitis during first and second lactations and sire transmitting abilities for somatic cell score, udder type traits, productive life, and protein yield. Data on clinical mastitis during first lactation were available for 1795 daughters (in six Pennsylvania herds, one Minnesota herd, and one Nebraska herd) of 283 Holstein sires. Data on clinical mastitis during second lactation were available for 1055 of these daughters. A total of 479 cows had 864 clinical episodes during first lactation, and 230 cows had 384 clinical episodes during second lactation. Clinical mastitis incidence and the total number of clinical episodes during each lactation were regressed on herd-season of calving (a classification variable), age at first calving, lactation length, and sire transmitting abilities taken one at a time. Linear effects, nonlinear effects, and odds ratios were estimated for sire transmitting abilities. Separate analyses were conducted on dependent variables that considered clinical mastitis from: all organisms, coagulase-negative staphylococci, coliform species, streptococci other than Streptococcus agalactiae, and the most common environmental organisms (coliform species and streptococci other than Streptococcus agalactiae). Heritability of clinical mastitis ranged from 0.01 to 0.42. Daughters of sires that transmit the lowest somatic cell score had the lowest incidence of clinical mastitis and the fewest clinical episodes during first and second lactations. Daughters of sires that transmit longer productive life, shallower udders, deeper udder cleft, and strongly attached fore udders had either fewer clinical episodes or lower clinical mastitis incidence during first and second lactations. The incidence of clinical mastitis and the number of clinical episodes per lactation may be reduced by selection for lower somatic cell score, longer productive life, shallower udders, deeper udder cleft, or strongly attached fore udders.

Animals↗