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Biomedical subjects

W S Swecker

Publications and source records attributed to W S Swecker.

17 recordsLinked to original sources
PubMed2006

Variation in Eimeria oocyst count and species composition in weanling beef heifers.

Rectal fecal samples were collected daily on 10 consecutive days in November 2004 from 11 weaned beef heifers to assess daily variation in fecal oocyst count and species composition. Subsequent samples were collected from the same animals on 15 April 2005 and 9 June 2005. Oocyst numbers were determined by the modified McMaster's test, and species were identified by examination of oocysts recovered with the Wisconsin sugar flotation technique. Soil samples were collected from the heifer pasture on 8 June 2005, and oocysts were quantified and identified to species. Mean fecal oocyst counts varied little at all sampling dates ranging from 134-377 oocysts/g. Ten Eimeria spp. were identified in fecal samples collected in November and April and 11 in June. Eimeria bovis was the most common species identified at all samplings. Mean species composition showed little variation during the 10-day sampling period in November, remained similar in April, and varied slightly in June. Twelve Eimeria spp. were identified in soil samples in proportions similar to those seen in fecal samples. The results indicate that clinically normal weanling beef heifers are likely to be infected with a diverse, but relatively stable, community of Eimeria spp.

Animals↗
PubMed2004

Pregnancy rates after timed AI of heifers following removal of intravaginal progesterone inserts.

Reproductive performance of dairy heifers was compared for each of 2 synchronization protocols: The first group of 54 heifers was synchronized using intravaginal progesterone inserts (CIDR) plus estradiol cypionate (ECP) on d 0, PGF(2alpha) on d 7, and ECP again on d 8 (CIDR-ECP); a second group of 56 heifers was synchronized using CIDR and ECP on d 0, PGF(2alpha) on d 7, and GnRH on d 9 (CIDR-GnRH). All heifers received timed artificial insemination (TAI) at 48, 56, or 72 h after CIDR removal on d 7. Pregnancy diagnosis was conducted by ultrasonography 32 +/- 1 d post AI to confirm pregnancy and at 60 +/- 1 d post AI to determine embryo survival. Ovaries were monitored by ultrasonography daily from d 0 to 7 and twice daily from d 8 to ovulation to examine emergence of a new wave of follicles, size of the ovulatory follicle, and timing of ovulation on 15 heifers per protocol. New follicular development was detected 3.7 +/- 0.2 d after CIDR insertion. Heifers receiving CIDR-ECP had a shorter interval from CIDR removal to ovulation than heifers receiving CIDR-GnRH (63.8 +/- 3.0 vs. 71.6 +/- 2.3 h, respectively); however, ovulation occurred 39.8 +/- 3.0 h after ECP or 23.6 +/- 2.3 h after GnRH. Diameters of ovulatory follicles did not differ between treatments. Overall pregnancy rate for synchronized heifers was 60.1%, and embryo survival was 98%. Pregnancy rate for heifers synchronized with CIDR-ECP was 63.0% and similar to that in heifers synchronized with CIDR-GnRH (57.1%). Pregnancy rate was affected by time of AI for heifers synchronized using CIDR-ECP but not for those synchronized with CIDR-GnRH. Heifers in the CIDR-ECP group that were inseminated 56 h after CIDR removal had a higher pregnancy rate (81.0%) compared with heifers inseminated 48 (66.7%) or 72 h (50.0%) after CIDR removal. Either ECP or GnRH used in a CIDR-based TAI program in dairy heifers can achieve acceptable reproductive performance.

Administration, Intravaginal↗
PubMed2001

Additive effects of a sodium chloride restricted diet and furosemide administration in healthy dogs.

OBJECTIVE: To determine the effects of a low or high sodium (Na) diet with or without furosemide administration on plasma electrolyte concentrations and the renin-angiotensin-aldosterone system in healthy dogs. ANIMALS: 20 healthy adult dogs. PROCEDURE: Dogs were randomly allotted to 4 groups of 5 dogs each as follows: dogs fed a low Na diet (0.08% Na and 0.8% chloride [CI] on a dry matter [DM] basis); dogs fed a low Na diet with added NaCl (1.0% Na and 2.2% Cl on a DM basis); dogs fed a low Na diet and treated with furosemide (2 mg/kg of body weight, PO, q 12 h); and dogs fed a low Na diet with added NaCl and treated with furosemide. Plasma electrolyte concentrations were measured on days 0, 21, and 35. Plasma renin activity and aldosterone concentration were analyzed by use of radioimmunoassays on days 0, 21, 35, and 53. RESULTS: Furosemide treatment significantly decreased plasma Cl concentration and significantly increased plasma renin activity and aldosterone concentration. Dogs fed a low Na diet had significantly higher plasma renin activities and plasma aldosterone concentrations. A significant interaction between a low Na diet and furosemide administration resulted in the lowest plasma Cl concentrations, highest plasma renin activities, and highest plasma aldosterone concentrations. CONCLUSIONS AND CLINICAL RELEVANCE: In healthy dogs, feeding a low Na diet and administering furosemide resulted in an additive effect on plasma Cl concentration, renin activity, and aldosterone concentration, which may be an important consideration for treating dogs with cardiac disease.

Aldosterone↗
PubMed2001

Effects of oral vitamin E supplementation during late gestation in beef cattle that calved in late winter and late summer.

OBJECTIVE: To determine effects of breed and oral vitamin E supplementation during late gestation on serum vitamin E and IgG concentrations in beef cows that calved in late winter and late summer and in neonatal calves. ANIMALS: 73 Angus and 43 Hereford primiparous and multiparous cows and their calves. PROCEDURE: Cows in groups that were homogeneous regarding breed and age distribution were randomly allotted to groups that were orally supplemented (n = 59) or not supplemented (57) with vitamin E beginning 30 days prior to onset of 65-day calving seasons. Supplemental vitamin E was provided in a vitamin-mineral mix offered free-choice until parturition. RESULTS: Cows that calved in late winter and were supplemented orally with vitamin E had higher serum vitamin E concentrations at calving and after calving than did unsupplemented cows; differences between groups before calving were not significant. Calves from supplemented multiparous cows had higher vitamin E concentrations than did calves from unsupplemented cows. Winter-born calves from supplemented Hereford cows had heavier 205-day adjusted weaning weights than did winter-born calves from unsupplemented Hereford cows. Supplementation did not affect vitamin E or IgG concentrations in the herd that calved in late summer and did not affect calf growth. CONCLUSIONS AND CLINICAL RELEVANCE: Oral vitamin E supplementation during late gestation may be economically beneficial in certain cow-calf operations in which late-gestation cows are consuming stored forages.

Animals↗
PubMed2000

Hypercalcemia and hypervitaminosis D in two lambs.

Twin 17-day-old crossbred male lambs were examined to determine the cause of weakness and failure to thrive. Hypercalcemia attributable to hypervitaminosis D was diagnosed. The milk replacer or an accidental overdose of an injectable vitamin D product was suspected to be the source, although a definite cause was not confirmed. Lambs responded favorably to palliative treatment (administration of saline [0.9% NaCl] solution to induce calcium diuresis) and changing the diet to another milk replacer.

Animal Feed↗
PubMed2000

Effects of supplemental parenteral administration of vitamin E and selenium to Jerseys and Holsteins during the nonlactating period.

OBJECTIVE: To determine effects of breed and supplemental administration of vitamin E and selenium (Se) during late gestation on circulating concentrations of these micronutrients in periparturient Jerseys and Holsteins. DESIGN: Randomized controlled clinical study. ANIMALS: 16 Jersey and 36 Holstein cows. PROCEDURE: Cows were allotted to blocks on the basis of breed and expected parturition date. Cows within blocks were randomly assigned to be given vitamin E or Se parenterally 3 to 4 weeks prior to anticipated parturition in a 2 x 2 factorial design. RESULTS: Results of ANOVA indicated Jerseys had higher blood concentrations of Se and lower serum concentrations of vitamin E than Holsteins at the end of lactation. Jerseys had higher blood concentrations of Se than Holsteins 3 to 4 weeks prior to parturition and at parturition. Selenium administration increased blood concentrations of Se at parturition. Administration of nutrients did not affect serum concentrations of vitamin E at parturition or 2 to 3 weeks after parturition or blood concentrations of Se 2 to 3 weeks after parturition. CONCLUSIONS AND CLINICAL RELEVANCE: Jerseys and Holsteins consuming rations of comparable Se content differ in blood concentrations of Se during the nonlactating period, suggesting breed-related differences in Se metabolism during late lactation and the nonlactating period. Parenteral administration of Se 3 to 4 weeks prior to anticipated parturition increased blood concentrations of Se at parturition; however, Se concentrations of both groups at parturition were considered within the reference range for clinically normal cattle.

Animals↗
PubMed1998

Serum immunoglobulin type G concentrations in calves produced by IVF and delivered by elective cesarean section.

Colostrum ingestion by neonatal calves is widely recognized to provide passive transfer of immunity. In this study immunoglobulin absorption from colostrum was evaluated in 54 IVF-produced calves. The IVF calves were delivered by Cesarean section on Days 275 to 277 of gestation, 24 h after the dams had been administered 30 mg dexamethasone. The calves suckled bottles or were force-fed 6 L of colostrum in the first 12 h of life. Colostrum was obtained from the first post-calving milking of recipient dams or from frozen storage reserves if dam secretion was not adequate. Immunoglobulin type G (IgG) content of both sources of colostrum was determined. Serum samples from the calves were collected at 0, 12 and 24 h of age and analyzed for IgG. Twenty dairy calves born vaginally served as the controls and were subjected to the same colostrum management protocol except that the colostrum was obtained only from frozen post-calving milk of dairy cows from the same farm. The control calves were also subjected to the same sampling protocol. The IVF group of calves ingested more IgG (P < 0.0001) and absorbed more IgG by 24 h of age (P < 0.0001) than their control group counterparts. Absorption of IgG was analyzed by comparing the g/kg body weight of IgG with serum IgG values at corresponding times after birth. Colostrum absorption efficiency was the same for both IVF and control groups of calves at 12 and 24 h of age. There was a maximum IgG dose above which additional increases in serum IgG were not realized. The slightly premature, Cesarean delivered IVF calves absorbed IgG from colostrum similarly to control calves delivered vaginally.

Animals↗
PubMed1998

Oral and parenteral vaccination of mice with protein-ergotamine conjugates and evaluation of protection against fescue toxicosis.

Acremonium coenophialum produces ergopeptide alkaloids in tall fescue (Festuca arundinacea Schreb.). These ergot alkaloids decrease serum alkaline phosphatase (ALP) activity, serum cholesterol and prolactin concentrations, as well as average daily gains (ADG) in cattle. The objective of this study was to evaluate the protection of anti-ergotamine antibodies induced by either oral or parenteral vaccination with protein-ergotamine conjugates or passive vaccination with anti-ergovaline, monoclonal antibodies in a murine model of fescue toxicosis. Ergotamine (EG) was conjugated to bovine serum albumin (BSA) and cholera toxin subunit B (CTB) by the Mannich reaction. Mice were blocked based on weight and randomly allocated into five groups of 10 mice each. Treatment groups were as follows: (1) group vaccinated intraperitoneally (ip) with a BSA-EG conjugate and fed an endophyte-infected (EI) fescue diet (BSA-EG group); (2) group orally vaccinated with a CTB-EG conjugate mixed with free cholera toxin (CT) and fed an EI fescue diet (CTB-EG group); (3) nonvaccinated group fed an EI fescue diet (EI group); (4) group passively vaccinated with anti-ergovaline, monoclonal antibodies and fed an EI fescue diet (MoAB group); and (5) nonvaccinated group fed an endophyte-free (EF) fescue diet (EF group). The EI diet contained 1.5 ppm of Ergovaline (EV), whereas no EV was detected in the EF diet.Respective diets were similar upon nutritional analysis. Unvaccinated mice in the EI group exhibited features of fescue toxicosis as indicated by decreased serum ALP activity and cholesterol, and decreased weight gain as compared to mice in the EF group. Antibodies against EG and EV were present in sera of mice in the BSA-EG and MoAB groups, respectively. Mice orally vaccinated with the CTB-EG conjugate developed secretory IgA (sIgA) antibodies and short-lived, systemic IgG responses against EG. Weight gains were increased in the BSA-EG and CTB-EG groups and tended to be increased in the MoAB group vs. the unvaccinated EI group. Serum ALP activity was decreased in the BSA-EG and MoAB groups as compared to the EF group. Serum ALP activity was further decreased in the BSA-EG vaccinated group as compared to the EI group. Cholesterol concentrations were decreased in the EI, BSA-EG and MoAB groups as compared to the EF group. Prolactin concentrations were similar in all groups.

Acremonium↗
PubMed1998

Monocyte immune cell response and copper status in beef steers that grazed endophyte-infected tall fescue.

A 3-yr study was conducted to evaluate immune response and Cu status of yearling beef steers as a consequence of grazing tall fescue (Festuca arundinacea Schreb.) infected (E+) with the endophyte fungus Neotyphodium coenophialum ([Morgan-Jones and Gams] Glenn, Bacon, and Hanlin). During a preliminary study in 1994, 24 weanling Angus and Angus x Hereford steers were blocked by breed and weight (initial BW 271 kg; SD 25) and were randomized to E+ and low endophyte (E-) fescue in pastures at Glade Spring, VA. Grazing began in April and was discontinued in July. In 1995 and 1996, 24 weanling Angus and Angus x Hereford steers (initial BW 249 kg, SD 20 and 240 kg, SD 15, respectively) were randomized to the E+ and E- pastures at Glade Spring during each year. Grazing began in April and continued until September in 1995 and October in 1996. In 1994, steers that grazed E+ fescue exhibited lower (P < .05) phagocytic activity, major histocompatibility complex (MHC) class II expression, ceruloplasmin, and serum Cu than steers that grazed E- tall fescue. During 1995, steers grazing E+ fescue had lower (P < .05) phagocytic activity and MHC class II expression than steers that grazed E- fescue. In 1996, one-half of the steers within each paddock received a Cu oxide bolus at the beginning of the grazing season. During 1996, phagocytic activity was lower (P < .01) and MHC class II expression tended (P < .07) to be lower in steers that grazed E+ tall fescue than in steers that grazed E- tall fescue. Copper supplementation increased (P < .05) MHC class II expression in July regardless of endophyte status over nonsupplemented steers. Steers that grazed E- tall fescue had higher (P < .05) plasma or serum Cu concentrations than steers that grazed E+ tall fescue in each year of the study. These data indicate that the endophyte compromised the immune function of grazing steers, and the data suggest a relationship with depressed Cu status.

Acremonium↗
PubMed1997

Evaluation of humoral immune responses in cattle grazing endophyte-infected or endophyte-free fescue.

Anecdotal reports suggest cattle with fescue toxicosis may not respond to vaccination and thus, experience increased incidence of Bovine Respiratory Disease Complex (BRDC) when shipped to feedlots. Fescue toxicosis causes hypoprolactemia in cattle. Hypoprolactemia decreases humoral immune responses in mice. Therefore, a study was conducted to compare the magnitude of primary and secondary humoral immune responses against specific antigens in cattle grazing endophyte-infected or endophyte-free fescue. Angus steers were blocked by weight and allocated into four groups. Two groups grazed endophyte-infected (EI) fescue and the other two groups grazed endophyte-free (EF) fescue. All steers were injected IM on d 0 and 21 with lysozyme without adjuvant and concanavalin. A (Con A) with sheep red blood cells (SRBC) in incomplete adjuvant of Freund. Steers were bled on days 0, 21 and 35 post-vaccination. Average daily gains (ADG), alkaline phosphatase (ALP) activity, cholesterol concentrations, rectal temperatures, and serum prolactin concentrations were measured to confirm fescue toxicosis in steers grazing EI fescue. Antibodies to Con A and SRBC were determined by ELISA and hemagglutination assay, respectively. The ADG were decreased for the EI group during the first month. Rectal temperature were elevated and serum prolactin concentrations were decreased in the EI group. Cholesterol and ALP concentrations also were decreased in the EI group. Primary and secondary immune responses against Con A tended to be increased and were increased against SRBC in the EI group. Antibodies against lysozyme were not induced in either group. In conclusion, cattle grazing EI fescue mounted similar humoral immune responses to vaccination, despite hypoprolactemia, as cattle grazing EF fescue. Increases in bovine respiratory disease in cattle maintained on EI fescue probably is not associated with lack of humoral immune response to vaccination protocols as a result of fescue toxicosis.

Acremonium↗
PubMed1995

Effect of selenium supplementation on colostral IgG concentration in cows grazing selenium-deficient pastures and on postsuckle serum IgG concentration in their calves.

Effects of selenium (Se) deficiency and supplementation on production of colostral immunoglobulins by beef cows and transfer of antigen-specific and nonspecific immunoglobulins to their calves were examined. Eight beef cows, with marginal to deficient Se status (blood Se concentration, 50 micrograms/L), were allotted by breed and age to 1 of 4 Se treatment groups (n = 20/group): no supplemental Se; parenteral administration of 0.1 mg of Se and 1 mg of vitamin E/kg of body weight; ad libitum consumption of 120 mg of Se/kg of salt-mineral mix (SMM); and parenteral administration of 0.1 mg of Se and 1 mg of vitamin E/kg plus ad libitum consumption of 120 mg of Se/kg of SMM. All cows were inoculated IM with lysozyme. Cows consumed Se-deficient pastures or hay (21 to 62 micrograms/kg) during the study that began at mid-gestation and ended at postpartum hour 24. Although the concentration of specific lysozyme antibodies was not affected, cows given 120 mg of Se/kg of SMM (treatments 3 and 4) had higher colostral IgG concentration (P < 0.002) than did Se-deficient cows (treatments 1 and 2). Calves from cows in treatments 3 and 4 had higher postsuckle serum concentrations of IgG (P < 0.01) than did calves from cows in treatments 1 and 2. Colostral IgM and calf serum IgM concentrations did not differ among treatments.

Animal Feed↗
PubMed1992

Immunodeficiency associated with lymphosarcoma in a horse.

Immune system dysfunction and immunoglobulin deficiency was diagnosed in a 2-year-old horse with disseminated lymphosarcoma. Prolonged (35 days) parenteral nutrition was delivered to support the horse during a period in which immune function studies could be performed. Correction of nutritional compromise by use of parenteral nutrition did not correct the immunoglobulin deficiency, and results of lymphocyte phenotype testing did not indicate abnormal proportions of leukocytes. Lymphoblast transformation studies were suggestive of a circulating immunosuppressive factor in the horse's serum. Normal cell function was detected when the cells were stimulated in precolostral equine serum.

Animals↗
PubMed1992

Canine bone shape analysis by use of a radiographic image-classification system.

A radiographic image-classification system was developed to analyze and compare the shape of the humerus of neonatal Labrador Retriever and Labrador Retriever x Beagle pups that were either phenotypically normal or affected with an ocular-skeletal dysplasia syndrome. The system consistently defined the shape of the humerus within the groups of pups studied and indicated a difference in the shape of the humerus between normal and affected pups. Results indicated that the radiographic image-classification system may be able to identify Labrador Retriever pups affected by the ocular-skeletal dysplasia syndrome at or shortly after birth.

Animals↗
PubMed1990

Nutritional influences on immunity.

There is no doubt that nutrient deficiencies and excesses can influence immune responses. Despite advances in the development of therapeutic agents, a competent immune system is crucial for prevention and resolution of disease. Leukocytes are some of the most metabolically active cells in animals. We know that growing animals require nutrients to sustain growth and reach their full potential, whether that is size, strength, speed, or agility. We do not expect kittens to grow or greyhounds to run without provision of adequate nutrients. To expect the immune system to function in the face of nutrient deficiency neglects our knowledge of the physiological needs of metabolically active tissues. Immune responses may be modified through dietary manipulations. However, the clinician must answer the question "to what end or consequence will the response be changed?" No "golden" nutrient ensures an appropriate immune response in all conditions, just as no "golden" drug heals all diseases. Our knowledge of nutrient-immune system interactions is increasing. Yet, for all of the current knowledge of nutrient effects on immunity, the words of Dr R.K. Chandra hold sterling advice, "Moderation is a good dictum in biology and medicine, and it applies equally to nutritional immunology."

Animal Nutritional Physiological Phenomena↗
PubMed1989

Influence of supplemental selenium on humoral immune responses in weaned beef calves.

Influence of supplemental Se on humoral immune response was measured in 60 weaned beef calves with marginal blood Se status. Calves were fed a Se-deficient diet consisting of corn silage, corn grain, and soybean meal. Blood Se concentrations, primary and secondary humoral immune responses to hen egg lysozyme inoculation, and weight gain were determined in a 70-day trial. Calves fed 20 mg of Se/kg of mineral mixture ad libitum had lower antibody responses (P less than 0.02), compared with calves fed 20 mg of Se/kg of mineral mixture and given 0.1 mg of Se and 0.22 IU of vitamin E/kg of body weight, IM, or with calves fed 80, 120, 160, or 200 mg of Se/kg of mineral mixture. Calves fed 80, 120, 160, or 200 mg of Se/kg of mineral mixture had higher (P less than 0.001) blood Se concentrations on day 70, compared with calves fed 20 mg of Se/kg of mineral mixture and given 0.1 mg of Se and 0.22 IU of vitamin E/kg of body weight, IM. Selenium supplementation had no effect on weight gain.

Administration, Oral↗
PubMed1988

The investigation of nutritional disorders.

The following list is presented as a summary of guidelines that may be helpful in the investigation of a nutritional disorder. 1. Identify the perceived herd or flock problem. The client's complaint usually reflects an appearance of clinical signs or a depression in production parameters. The practitioner should also identify subclinical manifestations and other concurrent problems. 2. Identify the affected population or subpopulation. Groups should be identified according to breed, sex, age, reproductive status, growth phase, and lactation status. It is critical to identify the affected population, as a diet can be adequate for one population and deficient or excessive for another. For example, 24-month-old Angus heifers in the first 60 days of lactation would have greater risk of protein-energy malnutrition than would 5-year-old Angus cows in their second trimester of gestation if both were fed a marginal hay ration. 3. Identify the nutritional requirements for the affected population. The National Research Council publications serve as a guideline in determining nutrient requirements. 4. Identify factors that influence nutrient requirements and feed intake. Environmental factors, such as ambient temperature, can affect both nutrient requirements and feed intake of the population. Housing conditions, such as muddy lots, can increase maintenance requirements. 5. Sample and evaluate the feedstuffs. Nutrient(s) must be bioavailable--that is, they must be in a form that can be ingested, digested, and absorbed by the animal. 6. Sample and evaluate water sources for quantity and quality. 7. Evaluate feed bunk management practices. 8. Examine the herd. Both affected and normal populations should be examined. 9. Evaluate and submit to a laboratory any animal samples that may relate to the disorder. 10. Assemble the data and develop a hypothesis to support a diagnosis. 11. Provide a written account of all recommendations for the producer.

Animals↗