Biomedical subjects

L W Douglass

Publications and source records attributed to L W Douglass.

At least 19 recordsLinked to original sources

PubMed2006

NOS3 gene polymorphisms and exercise hemodynamics in postmenopausal women.

We tested whether the G894T and T-786C NOS3 polymorphisms were associated with exercise cardiovascular (CV) hemodynamics in sedentary, physically active, and endurance-trained postmenopausal women. CV hemodynamic parameters including heart rate (HR), systolic (SBP) and diastolic (DBP) blood pressures and cardiac output (Q), as determined by acetylene rebreathing, stroke volume (SV), arteriovenous oxygen difference (a-vO2 diff), and total peripheral resistance (TPR) were measured during submaximal (40, 60, 80 %) and maximal (approximately 100 % VO2max) exercise. NOS3 G894T genotype was not significantly associated, either independently or interactively with habitual physical activity (PA) level, with SBP, Q, TPR, or a-vO2 diff during submaximal or maximal exercise. However, NOS3 894T non-carriers had a higher submaximal exercise HR than NOS3 894T allele carriers (120 +/- 2 vs. 112 +/- 2 beats/min, p = 0.007). NOS3 894T allele carriers had a higher SV than 894T non-carriers (78 +/- 2 vs. 72 +/- 2 ml/beat, p = 0.03) during submaximal exercise. NOS3 894T non-carriers also had a higher maximal exercise HR averaged across habitual PA groups than T allele carrier women (165 +/- 2 vs. 158 +/- 2 beats/min, p = 0.04). NOS3 894T allele carriers also tended to have a higher SV during maximal exercise than 894T non-carriers (70 +/- 2 vs. 64 +/- 2 ml/beat, p = 0.08). NOS3 T-786C genotype was not significantly associated, either independently or interactively, with any of the CV hemodynamic measures during submaximal or maximal exercise. These results suggest an association of NOS3 G894T genotype with submaximal and maximal exercise CV hemodynamic responses, especially HR, in postmenopausal women.

Blood Pressure↗

PubMed2005

No association between ACE I/D polymorphism and cardiovascular hemodynamics during exercise in young women.

The ACE I/D polymorphism has been shown to interact with habitual physical activity levels in postmenopausal women to associate with submaximal and with maximal exercise hemodynamics. This investigation was designed to assess the potential relationships between ACE genotype and oxygen consumption (VO2), cardiac output (Q), stroke volume (SV), heart rate (HR), blood pressure (BP), total peripheral resistance (TPR), and arteriovenous oxygen difference ([a-v]O2 diff) during submaximal and maximal exercise in young sedentary and endurance-trained women. Seventy-seven 18-35-yr-old women underwent a maximal exercise test and a number of cardiac output tests on a treadmill using the acetylene rebreathing technique. ACE genotype was not significantly associated with VO2max (II 41.4+/-1.2, ID 39.8+/-0.9, DD 39.8+/-1.1 ml/kg/min, p=ns) or maximal HR (II 191+/-2, ID 191+/-1, DD 193+/-2 bpm, p=ns). In addition, systolic and diastolic BP, (a-v)O2 diff, TPR, SV, and Q during maximal exercise were not significantly associated with ACE genotype. During submaximal exercise, SBP, Q, SV, HR, TPR, and (a-v)O2 diff were not significantly associated with ACE genotype. However, the association between diastolic BP during submaximal exercise and ACE genotype approached significance (p=0.08). In addition, there were no statistically significant interactions between ACE genotype and habitual physical activity (PA) levels for any of the submaximal or the maximal exercise hemodynamic variables. We conclude that the ACE I/D polymorphism was not associated, independently or interacting with habitual PA levels, submaximal, or maximal cardiovascular hemodynamics in young women.

Adolescent↗

PubMed2003

Leptin suppresses food intake and body weight in corticosterone-replaced adrenalectomized rats.

Intracerebroventricular (ICV) injections of leptin decrease food intake and body weight while increasing energy expenditure. Some of these effects are reportedly enhanced in bilaterally adrenalectomized (ADX) rats. The purpose of the present experiment was to establish the time course of the suppression in body weight and food intake after an ICV injection of leptin. We wanted to establish the effect of varying doses of corticosterone (CORT) on body weight and food intake suppression by using separate groups of ADX, ADX and corticosterone-treated and sham-operated Sprague-Dawley rats. All rats were implanted with cholesterol pellets that varied in CORT content. During the same surgical session, all rats were fitted with a cannula in the lateral ventricle. After recovering from surgery, each rat was administered a 5- micro g ICV injection of leptin. ADX rats that were treated with CORT replacement lost more (P < 0.05) weight and took longer (P < 0.05) to return to baseline body weight than sham-operated controls. Leptin injection decreased food consumption to a greater extent (P < 0.05) in the ADX groups treated with CORT than in the sham-operated controls. Plasma insulin increased in a dose-dependent manner in the ADX rats as a function of CORT replacement. The higher of the two CORT replacement doses used in this experiment restored circulating CORT to levels observed in sham-operated controls. Contrary to earlier reports, physiological doses of CORT appear to enhance leptin-induced weight loss.

Adrenalectomy↗

PubMed2002

Evaluation of chemical disinfectants for the elimination of Salmonella biofilms from poultry transport containers.

Containers used in transporting live poultry between production and processing units are a primary source of contamination for processed poultry products. Because disinfection of transport containers (TC) has been difficult to accomplish, it is probable that the choice of appropriate disinfectant and its application are partially or wholly responsible for the failure to adequately eliminate pathogens from TC. Therefore, 13 commercial disinfectants were selected and evaluated for their capacities to destroy Salmonella. The disinfectants were applied in various concentrations on prescribed areas (10 cm diameter circle) of galvanized steel surfaces (representative of TC material) that were artificially contaminated with Salmonella (10(8) cfu/mL) with a mixture of organic material. Likewise, coupons (1.9 cm2) made of the same metallic surfaces and covered with biofilms of Salmonella spp. were tested in the same manner for each disinfectant. Two of the disinfectants completely eliminated Salmonella on the artificially contaminated and biofilm-covered surfaces. These compounds produced logarithmic reductions in Salmonella populations as high as 7.18 within 2 min. One of the two effective disinfectants contained sodium hypochlorite and was effective at a concentration of 0.05% (vol/vol). The other disinfectant was an alkaline peroxide compound and was effective at a concentration of 1% (wt/vol). Evaluation of these two disinfectants under simulated conditions suggested that application under the prescribed regimen could result in effective elimination of Salmonella from TC within a limited period.

Animals↗

PubMed2001

Cytokine and lymphocyte profiles in miniature swine after oral infection with Toxoplasma gondii oocysts.

Pigs are considered an important source of Toxoplasma gondii infection for humans. A major strategy for immune prophylaxis of toxoplasmosis in swine is the understanding of the immune response against T. gondii infection. The phenotype of peripheral blood mononuclear cells (PBMC) and the kinetics of interferon-gamma (IFN-gamma), interleukin-12 (IL-12) and interleukin-10 (IL-10) transcriptional changes were characterised in miniature swine following infection. A total of 66, 4-9-month-old miniature swine were used for three experiments performed over a period of 2 years. All pigs were fed iota1000 oocysts of the VEG strain of T. gondii and blood samples were obtained on the day of inoculation and at days 3, 6, 10, 17, 25, 32 and 40 after infection. An increase in expression of activation markers CD25 and SLA-DQ was detected in the first week of infection. A significant increase in the percentage of CD8+cells was observed in the second week of infection. Relative competitive RT-PCR analysis indicated an increase in IFN-gamma mRNA as well as a reduction in IL-10 mRNA during the second week post infection. Increase in IL-12 transcription was not observed until the fourth week of infection. The ability of the pigs to respond to T. gondii infection by simultaneously inducing pro-inflammatory cytokines early and anti-inflammatory cytokines later is a likely indication of the requirement to strike a balance between controlling parasite growth and avoiding cytokine toxicity.

Administration, Oral↗

PubMed2001

Characterization of lymphocyte subsets from mucosal tissues in neonatal swine.

Monitoring differences in lymphocytes during neonatal development constitutes a key to understanding the developing piglet's natural and pathological immune responses. A survey was conducted to accumulate information on the phenotype of lymphocytes isolated from blood, lymph nodes, and lymphoid associated structures of the pig small intestine of conventional pigs from day 1 to 47 of age and inbred miniature pigs between 12 and 82days. The effect of weaning, and age before and after weaning, were also evaluated. Weaning had a significant effect on the number of CD4(+), CD8(+), double positive CD4(+)/CD8(+), CD21(+), deltagammaTCR(+), SWC3(+) and SLA-DQ(+) cells. Aging of the pig before and after weaning resulted in significant changes in lymphocytes isolated from mesenteric lymph nodes and ileal sites. These results constitute an important baseline for studying mucosal immune response of neonatal pigs and identifying factors that influence the ability of the neonate to respond to the stresses and antigenic exposure associated with weaning.

Animals↗

PubMed2001

Cytotoxic effects of peroxynitrite, polymorphonuclear neutrophils, free-radical scavengers, inhibitors of myeloperoxidase, and inhibitors of nitric oxide synthase on bovine mammary secretory epithelial cells.

OBJECTIVE: To determine cytotoxic effects of activated polymorphonuclear neutrophils (PMN) and peroxynitrite on bovine mammary secretory epithelial cells before and after addition of nitric oxide synthase inhibitors, myeloperoxidase (MPO) inhibitors, and free-radical scavengers. SAMPLE POPULATION: Polymorphonuclear neutrophils from 3 lactating cows. PROCEDURE: Cells from the bovine mammary epithelial cell line MAC-T were cultured. Monolayers were treated with activated bovine PMN, lipopolysaccharide (LPS), phorbol 12-myristate 13-acetate (PMA), 3-morpholino-sydnonimine (SIN-1), 4-amino-benzoic acid hydrazide (ABAH), NG-monomethyl-L-arginine, histidine, and superoxide dismutase (SOD). At 24 hours, activity of lactate dehydrogenase in culture medium was used as a relative index of cell death. Tyrosine nitration of proteins in MAC-T cell lysates was determined by visual examination of immunoblots. RESULTS: Lipopolysaccharide, PMA, and < or = 0.1 mM SIN-1 were not toxic to MAC-T cells. Activated PMN, > or = 6 mg of histidine/ml, and 0.5 mM SIN-1 were toxic. Together, histidine and 500,000 activated PMN/ml also were toxic. NG-monomethyl-L-arginine did not have an effect, but ABAH decreased PMN-mediated cytotoxicity. Ten and 50 U of SOD/ml protected MAC-T cells from cytotoxic effects of 0.5 mM SIN-1. Compared with control samples, nitration of MAC-T tyrosine residues decreased after addition of 500,000 PMN/ml or > or = 6 mg of histidine/ml. Superoxide dismutase increased and SIN-1 decreased tyrosine nitration of MAC-T cell proteins in a dose-responsive manner. CONCLUSIONS AND CLINICAL RELEVANCE: Peroxynitrite, MPO, and histidine are toxic to mammary secretory epithelial cells. Superoxide dismutase and inhibition of MPO activity mitigate these effects. Nitration of MAC-T cell tyrosine residues may be positively associated with viability.

Aniline Compounds↗

PubMed2001

Use of growth hormone response to growth hormone-releasing hormone to determine growth potential in beef heifers.

The response of GH to GHRH at weaning is known to predict postweaning growth and body composition in beef bulls. The objective of this study was to determine whether GH response to a challenge of GHRH and plasma IGF-I can predict growth rate and body composition in the beef heifer. Growth hormone response to a challenge with two doses of GHRH was measured in 67 Angus heifers averaging 225 d of age (SD = 21) and 217 kg BW (SD = 32). Blood samples were collected at 0 and 10 min relative to an initial "clearance dose" (4.5 micrograms GHRH/100 kg BW) and again, 3 h later, relative to a challenge dose (1.5 or 4.5 micrograms GHRH/100 kg BW). Each animal received each of the two challenge doses, which were randomly assigned across 2 d of blood collection. Serum GH concentration was measured by RIA. Plasma was collected every 28 d during a 140-d growth test and assayed for IGF-I by RIA. Body weight was measured every 28 d and hip height was measured at weaning and at the end of a 140-d growth test. Average daily gain was calculated on d 140 of the growth test and body composition measurements were estimated by ultrasound 2 wk after completion of the growth test. Responses to the two GHRH challenges were dose-dependent (P < 0.05). Average daily gain tended to be related to GH response to the 1.5 micrograms GHRH/100 kg BW dose (R2 = 0.05; P = 0.06), but no relationship was observed at the 4.5 micrograms GHRH/100 kg BW dose (R2 = 0.00; P = 0.93). An inverse relationship (R2 = 0.06; P = 0.02) was observed between response to the 1.5 micrograms GHRH/100 kg BW dose and intramuscular fat percentage. Mean plasma IGF-I concentration was positively associated with ADG (R2 = 0.06; P < 0.01). Growth hormone response to GHRH is modestly related to body composition but not to ADG in weanling beef heifers and likely has limited use in evaluation of growth performance in replacement beef heifers.

Animals↗

PubMed2001

Incidence of mastitis in beef cows after intramuscular administration of oxytetracycline.

There is limited information on the value of antibiotic therapy for mastitis in beef cows. Effects of antibiotic treatment at weaning and the subsequent calving on calf weaning weight, milk somatic cell counts, milk components, and intramammary infection were studied in beef cows. Additionally, effects of number of infected mammary quarters, number of dry mammary quarters, type of intramammary pathogen, and parity on response variables were determined. Cows (n = 192) were randomly assigned to treatments in a 2 x 2 factorial arrangement; factors were time of treatment (weaning and after calving) and treatment (vehicle and vehicle plus antibiotic). Oxytetracycline (LA-200) or vehicle was administered intramuscularly following collection of quarter milk samples at weaning and calving. Percentage of infected cows and quarters averaged 43.4 and 16.4%, respectively, at calving and increased (P < 0.05) to 53.7 and 29.7% at weaning. Calves from cows with one or two dry quarters weighed 12.7 kg less (P < 0.05) at 90 d after calving and 18.7% less (P < 0.05) at 212 d after calving than calves from cows with no dry quarters. Calves from cows with three or four infected quarters weighed 17.5 kg less (P < 0.05) at 90 d and 25.5 kg less (P < 0.05) at weaning than calves from cows with two or fewer infected quarters. Infections by Staphylococcus aureus and coagulase-negative staphylococci were the most common and accounted for 67 and 78% of the infections. Percentages of infected cows and quarters, infections caused by S. aureus, and dry quarters increased (P < 0.05) with parity. No differences were found among antibiotic treatments for any of the response variables studied. Intramuscular oxytetracycline was not effective in the control of mastitis in beef cows under the conditions of the study.

Animals↗

PubMed2001

Immunization with Staphylococcus aureus lysate incorporated into microspheres.

Antibiotics are of limited value against Staphylococcus aureus due to development of resistant strains, scar tissue formation, and blockage of ducts due to inflammation. Though macrophages are the predominant cell type in the mammary gland, they are primarily scavenger cells and are not effective against bacteria entering the gland. Neutrophil phagocytosis is the bovine's primary defense against S. aureus mastitis. Attempts to develop vaccines that enhance neutrophil phagocytosis by stimulating production of opsonizing antibodies to S. aureus have met with limited success because of the low immunogenicity of the exopolysaccharide capsule surrounding S. aureus. Staphylococcus aureus can also adhere to and penetrate epithelial tissue. This study was conducted to determine whether lysates of S. aureus encapsulated in biodegradable microspheres would increase the production of opsonizing antibodies to capsule and block adherence. Four groups of four cows each were injected with 1 ml of the respective treatment in the area of the supramammary lymph node and 1 ml in the hip muscle. The treatments were: lysate in NaCl, lysate in Freund's incomplete adjuvant (FICA), lysate in microspheres in NaCl, and lysate in microspheres in FICA. Antigen in microspheres produced a similar antibody response to antigen emulsified in FICA, but to a lesser magnitude. Antigen in microspheres produced antibodies that were more opsonic for neutrophils at 20 and 52 wk postimmunization and inhibited S. aureus adherence to mammary epithelium. Ability to control antigen release and presentation, and the benefit of a single injection for long-term immunity using microspheres warrants additional studies.

Animals↗

PubMed2000

Characterization of the contribution of water activity and moisture content to the population distribution of Salmonella spp. in commercial poultry houses.

Because Salmonella spp. can be spread from the production environment to the consumer, strategies are required to control Salmonella. One such intervention involves control of the distribution of the organism in poultry litter. In this regard, we have attempted to determine whether Salmonella spp. are uniformly distributed throughout the litter of commercial poultry houses, or if they are unevenly localized to "hot spots" associated with high surface litter water activity (Aw) and high total moisture levels. Of the 86 houses sampled, 48 (55.8%) were positive for Salmonella spp. using a combination of the drag swab and targeted litter culturing methods. Data are presented that show that elevated Aw and percentage moisture content values representative of targeted litter samples or whole-house moisture status are not statistically predictive of Salmonella contamination, using either drag swab or targeted litter culture results as indicators of contamination. This study suggests that favorable environmental conditions for the growth of Salmonella are unequally dispersed in poultry houses. Because there is not equivalent distribution of salmonellae in the surface litter, the drag swab technique is apparently necessary to adequately survey for Salmonella spp. contamination. The findings further suggest that the development of a methodology to detect areas within houses that possess risk factors favorable for Salmonella growth must also include elevated Aw and percentage moisture content levels. This capability may enable a grower to detect and intervene in these targeted areas with neutralizing procedures, agents, or other substances to provide significant reduction of Salmonella or other poultry-associated food-borne pathogens.

Animals↗

PubMed2000

Effects of intramammary infection and parity on calf weaning weight and milk quality in beef cows.

The objectives of this study were to determine 1) the effect of intramammary infection on calf weaning weight, milk somatic cell count, and milk composition, and 2) the effect of parity on percentages of infected cows, infected quarters, and blind quarters. The number of infected quarters, milk somatic cell counts, milk components, and intramammary infection were studied at weaning in 164 beef cows. The percentage of infected cows ranged from 61.9% at first parity to 66.7% at fifth to ninth parities. Cows with three or four infected quarters had higher (P < .01) milk somatic cell counts than cows with zero, one, or two infected quarters. Among bacterial isolates, Staphylococcus aureus-infected quarters had the highest (P < .01) milk somatic cell count. Percentages of butterfat and lactose were lower (P < .01) in milk from infected quarters than from uninfected quarters. Infections by S. aureus and coagulase-negative staphylococci were the most common and accounted for 67 to 78% of the infections. Percentages of infected quarters and infections caused by S. aureus increased with parity (P < .01). Intramammary infections did not affect (P > .10) calf weaning weight. In conclusion, intramammary infection had no effect on calf weaning weight but increased milk somatic cell count and decreased the percentage of protein, lactose, solids-not-fat, and butterfat. The number of infected and blind mammary quarters increased with parity.

Animals↗

PubMed2000

Predicting growth in angus bulls: the use of GHRH challenge, insulin-like growth factor-I, and insulin-like growth factor binding proteins.

Plasma IGF-I, IGF binding protein-2 (IGFBP-2), and IGFBP-3 were quantified in growing Angus bulls (n = 56) to determine their relationship with postweaning growth and carcass ultrasound measurements. In addition, GH response to GHRH challenge (area-under-the-curve GH [AUC-GH) was determined for each bull as part of a previous study. Blood was collected by jugular venipuncture at the start of a 140-d postweaning growth performance test and at 28 d intervals for plasma IGF-I determination by RIA. Plasma IGFBP-2 and -3 content was measured at the start of the study, on d 70, and d 140 by Western ligand blotting. Individual weights and hip heights were measured every 28 d during the study and carcass longissimus muscle area, intramuscular fat percentage, and carcass backfat were estimated by ultrasound on d 140. Greater plasma IGF-I at the start of the performance test was associated with reduced postweaning ADG and increased longissimus area. Throughout the performance test period, the correlations between plasma IGF-I and hip height were consistently positive, ranging from 0.10 to 0.38, but the correlations between ADG and IGF-I varied from -0.32 to 0.31. Age-adjusted d-1 plasma IGFBP-2 was related to ADG during the performance test, explaining nearly 30% of the variation in ADG. A model combining weaning age, IGFBP-2, and AUC-GH showed a strong relationship with ADG (R2 = 0.40). Plasma IGFBP-2 and -3 were not related to carcass characteristics, and IGFBP-3 was not related to growth rates. This study provides additional evidence for the variable relationship between plasma IGF-I and growth rates in cattle. A significant positive relationship between plasma IGFBP-2, AUC-GH, and postweaning ADG warrants further investigation.

Animals↗

PubMed2000

Effects of photoperiodic manipulation during the dry period of dairy cows.

Thirty-four lactating Holstein cows were dried off 60 d prior to their expected calving date, paired by calving date, and randomly assigned to one of two photoperiod treatments: long-day photoperiod (n = 18; 16 h light: 8 h dark/d) or a short-day photoperiod (n = 16; 8 h light: 16 h dark/d) to determine if manipulation of photoperiod during the dry period would impact milk yield in the subsequent lactation. At parturition, calf weight, height, and length were measured and the cows were moved into ambient lighting conditions (November 1996 to January 1997 and November 1997 to January 1998, 39 degrees latitude) with the rest of the University of Maryland herd. After parturition, milk yield and composition were measured for 16 wk. Prolactin concentrations were higher by 11.7 ng/ml in the long-day photoperiod treatment group than for the cows on a short-day photoperiod. During lactation cows previously exposed to a short-day photoperiod produced 3.2 kg/d more milk than long-day photoperiod cows. Energy-corrected milk yield was greater in short-day photoperiod than in long-day photoperiod cows. Treatment did not affect calf growth, milk composition, or plasma insulin growth factor I concentrations. In conclusion, manipulation of photoperiod during the dry period of dairy cows may be a useful management tool for increasing milk yield in the subsequent lactation.

Animals↗

PubMed2000

Evaluation of 1.6% phenol as a premilking and postmilking teat dip in preventing new bovine intramammary infections.

We evaluated the effectiveness of a 1.6% phenol-based teat dip using both a teat skin assay and natural exposure field trial. A teat skin assay was conducted to ascertain the concentration of phenol + phenate to be used in the field study. One percent and 0.5% iodine, and 0.5, 1.1, and 1.6% phenol + phenate were compared using Escherichia coli and Staphylococcus aureus. Logarithmic reductions for S. aureus were 2.2 and 2.8 for 0.5 and 1% iodine, and 1.3, 2.1, and 2.8 for 0.5, 1.1, and 1.6% phenol + phenate, respectively. Logarithmic reductions for E. coli were 3.3 and 3.8 for 0.5 and 1% iodine, and 1.2, 1.9, and 2.6 for 0.5, 1.1, and 1.6% phenol + phenate, respectively. A concentration of 1.6% phenol + phenate was chosen as experimental teat dip, and 0.5% iodine served as control. The field study was conducted at Beltsville (n = 185) and Clarksville (n = 100) dairy herds using a split herd design. Teat dips were used premilking and postmilking for 12 mo. The number of new intramammary infections (IMI) for the Beltsville herd in iodine and phenol + phenate teat dipped cows were: 29 and 35 for major pathogens, and 81 and 72, for minor pathogens. For the Clarksville herd, number of new intramammary infections in iodine and phenol + phenate teat dipped cows was 9 and 10 for major pathogens, and 50 and 60 for minor pathogens. Rates of IMI per quarter day per lactation were not different for either herd or when herd data were combined. The number of clinical mastitis cases per 100 cows per month were similar in both treatments. The incidences of new IMI and clinical mastitis were similar using both dips.

Animals↗

PubMed2000

Production of antibodies to Staphylococcus aureus serotypes 5, 8, and 336 using poly(DL-lactide-co-glycolide) microspheres.

Staphylococcus aureus is responsible for a major portion of the economic losses due to mastitis. Attempts to produce a vaccine to prevent S. aureus mastitis have been hampered by the low immunogenicity of the polysaccharide, which forms on the surface of the organism when it enters the mammary gland. The polysaccharide inhibits phagocytosis and destruction of the organism by neutrophils. This study was conducted to determine if S. aureus polysaccharide serotypes 5, 8, and 336 conjugated to a protein and incorporated in poly(DL-lactide-co-glycolide) microspheres would enhance the production of opsonizing antibodies to the polysaccharide. Cows were immunized with either polysaccharide conjugates emulsified in Freund's incomplete adjuvant or polysaccharide conjugates encapsulated in poly (DL-lactide-co-glycolide) microspheres emulsified in Freund's incomplete adjuvant. All cows produced sustained antibody titers to the three polysaccharide serotypes. Cows immunized with microspheres had higher antibody titers. Cows in both groups produced increased concentrations of IgG1 and IgG2 antibodies; neither group produced an increase in IgM. Immune sera from cows immunized with conjugates alone increased phagocytosis, which decreased at the end of the study. Sera from cows immunized with conjugates in microspheres increased phagocytosis, which was sustained at the end of the study. Immune sera from both groups decreased bacterial adherence to bovine mammary epithelial cells. These data showed that a single injection of antigen in microspheres produced higher titers and more sustained enhancement of phagocytosis, which could aid in the defense of the cow against S. aureus infections.

Animals↗

PubMed2000

Diets deficient in rumen undegraded protein did not depress milk production.

The objective of this study was to evaluate the National Research Council's recommendations for feeding levels of rumen undegraded protein (RUP) for cows fed a one-group total mixed ration. Sixty Holstein cows were paired by parity (1 to 6) and DIM (23 to 315) and were randomly assigned to one of two treatment sequences. Diets contained alfalfa silage (30% diet DM) and corn silage (26% diet DM), and were isonitrogenous (16% CP) and isocaloric (1.71 Mcal/kg). Soybean meal, protected soybean meal (Soy Best), and urea were used to make ration protein fractions that were predicted to be 35 or 29% RUP. The 35% RUP diet was formulated to provide 98 and 105% of the average requirement for RUP and rumen degraded protein (RDP), respectively. The ration containing 29% RUP provided 79 and 117% of average required RUP and RDP, respectively. All cows were group-fed the high RUP diet during a 2-wk pretreatment period, and then were fed one ration for 4 wk followed by the other for 4 wk according to their assigned treatment sequence. Data were collected in the last wk of each period. Mean milk production, milk fat, and milk protein were 32.6 kg/d, 4.35%, and 3.36%, respectively, with no treatment differences. Treatment response was not affected by degree of predicted RUP deficiency. National Research Council requirements for RUP may be too high for cows fed diets similar in energy to a one-group total mixed ration. Alternatively, estimates of RUP content of feedstuffs may be low.

Animal Feed↗

PubMed1999

Theory of Reasoned Action predicts milk consumption in women.

OBJECTIVE: To determine the factors influencing the consumption or avoidance of milk in women. SUBJECTS/SETTING: One hundred women completed food frequency questionnaires and a milk attitudes questionnaire framed within the Theory of Reasoned Action and performed sensory evaluations of different milk samples. STATISTICAL ANALYSES: Differences among milk types were assessed using 2-way analysis of variance and least-significant-difference mean comparison procedures. Correlation and multiple regression analyses, and standardized partial regression coefficients, were used to determine the contribution of each component of the model in predicting behavior. RESULTS: Mean age of the 100 subjects was 39 years (range = 20-70 years). Milk consumption among subjects was low; 23 subjects indicated that they seldom or never drank milk. Data from the dairy frequency questionnaire showed that the primary milk for 42%, 36%, 27%, and 18% of the milk drinkers was skim, 2%, 1%, and whole, respectively (subjects could indicate more than 1 type of milk consumed). The Theory of Reasoned Action indicated that health and familiarity belief items were most associated with attitudes toward milk consumption. Skim milk had significantly lower scores for taste and texture belief items than 1%, 2%, and whole milk (P < .05), yet more subjects reported that they drank skim milk (42%) than the other milk types. Sensory evaluation demonstrated that subjects linked whole milk significantly more than skim milk (P < .05). CONCLUSIONS/APPLICATIONS: Some people continue to consume skim milk for reasons other than beliefs about taste and texture or actual sensory preference. This study identifies important factors contributing to milk consumption such as beliefs, attitudes, and sensory evaluation, which can be used to develop a specific framework in which to examine other components of milk consumption behavior.

Adult↗