Immune response of calves experimentally infected with non-cell-culture-passaged bovine respiratory syncytial virus

The immune response of calves was studied following infection with non-cell-passaged Bovine respiratory syncytial virus (BRSV). Two groups of 6 specific pathogen free (SPF) calves were housed in separate isolation rooms. One group was inoculated intranasally with a non-cell-passaged BRSV strain and the control group was mock-infected. A BRSV specific antibody response was observed for all the BRSV infected calves. These antibodies were shown to have neutralizing activity. No lymphocyte proliferation response was detected in the mock-infected group whereas three animals in the infected group were positive three weeks after the infection. All BRSV-infected calves, except one, produced interferon-gamma (IFN-gamma) one week post-infection and IFN-gamma was observed in all six infected calves after three weeks. The control group showed no IFN-gamma synthesis. In spite of the limits of the BRSV infection model, humoral and cellular immune responses were actively developed by all the calves against this pathogen.     

Pathological and in situ hybridisation findings in calves experimentally infected with bovine adenovirus type 4

BACKGROUND: To identify the determinants of the geographic distribution of ischaemic heart disease (IHD) mortality in Spain. POPULATION AND METHODS: Ecological study at the provincial level. Data are obtained from the 1976-1980 vital statistics, the 1964-1965 Household Budget Survey and the 1970 Population Census. RESULTS: Consumption of wine, chicken, fish, and vegetables, as well as illiteracy, explain 47% of IHD mortality. Consumption of wine alone exhibits a statistically significant relationship (p < 0.05) with IHD mortality. Moderate consumption of wine is negatively associated with IHD mortality, whereas higher consumption reveals a positive association. CONCLUSION: Results are consistent with those from an earlier study in Spain for the 1983-1987 period.     

Lymphadenopathy and non-suppurative meningo-encephalitis in calves experimentally infected with bovine immunodeficiency-like virus (FL112)

At least 10% of spontaneous chromosomal antibiotic resistant mutants of bacteria express a strain-dependent graded reduction of virulence; this correlates linearly with a prolonged generation time. Occasionally, these mutants are temperature sensitive or/and auxotrophe. The work described in this paper provides evidence that in such strains the resistance and the accompanying markers exist only as a functional genetic unit. In a series of transduction experiments with a pathogenic strain of Salmonella typhimurium, it was found that without exception, the resistance and the additional markers were 100% simultaneoulsy transferred. Furthermore, antibiotic-resistant Escherichia coli mutants with prolonged generation time, were isolated from faecal samples; it is thus indicated that, such innocuous mutants occur at any time in the intestine. It is concluded that concerns connecting such mutants to the possibility of resistance dissemination are unfounded; furthermore, even if transfer of resistance occurred, only attenuated strains would be disseminated.     

Effects of low energy diets followed by a compensatory diet on body weight gain and plasma hormone concentrations in bull calves

Holstein bull calves at 138.4 d of age were fed one of four diets that contained 2.28, 2.43, 2.61, or 2.8 Mcal of metabolizable energy/kg of dry matter and 10.8, 11.7, 12.8, or 13.9% crude protein, respectively, for 77 d followed by a diet that contained 2.80 Mcal of metabolizable energy/kg of dry matter and 13.9% CP. During the energy restriction period, the metabolizable energy of the diets was positively correlated with the plasma concentration of insulin-like growth factor-I, which was positively correlated with daily body weight (BW) gain during this period and the plasma concentration of total thyroxin. During the first 37 d of the realimentation period, compensatory growth occurred, and the rate of increase in plasma concentrations of insulin-like growth factor-I was positively correlated with that of daily BW gain. At d 37 of the compensatory period, the mean plasma concentration of total thyroxin in calves in three of the four groups did not differ significantly; only the concentration of total thyroxin in the plasma of calves fed the highest energy restricted diet was significantly higher. The mean BW of calves in groups fed the high energy diets during the restriction period tended to be heavier even after 158 d of the realimentation period.     

Effect of method of delivery of propylene glycol on plasma metabolites of feed-restricted cattle

Methods of administering propylene glycol to reduce plasma nonesterified fatty acids (NEFA) during feed restriction of cattle were evaluated. Treatments were 1) no propylene glycol supplementation, 2) propylene glycol provided as an oral drench once per day, 3) propylene glycol mixed with concentrate and fed separately from forage, or 4) propylene glycol blended as part of the total mixed ration (TMR). Prior to or during feed restriction at 50% of ad libitum intake, propylene glycol was provided once daily at 2.5 ml/kg of body weight. Prior to feed restriction, administration of propylene glycol as an oral drench or mixed with concentrate was more effective in increasing serum insulin than was feeding propylene glycol as part of the TMR. During feed restriction, administration of propylene glycol as an oral drench or mixed with concentrate resulted in higher serum insulin and lower plasma NEFA concentrations than did feeding propylene glycol as part of the TMR. Propylene glycol decreased the molar percentage of ruminal acetate and the ratio of acetate to propionate. Propylene glycol administered as an oral drench or mixed with concentrate and fed separately from forage appeared to be more effective than feeding propylene glycol as part of the TMR for influencing plasma NEFA in cattle during feed restriction.     

Development of PCR tests for the detection of bovine herpesvirus-1, bovine respiratory syncytial viruses and pestiviruses

The development of PCR assays for detection of BHV-1, BRSV, BVDV and another pestiviruses is summarized. A polymerase chain reaction assay based on primers selected from the viral gI glycoprotein gene detected 3 fg pure BHV-1 DNA, 0.1-1.0 TCID50 or a single infected cell. No amplification was observed with DNA from BHV-2, BHV-3, BHV-4, OHV-1 or OHV-2. However, a fragment of the correct size (468 bp) was amplified using DNA from herpesviruses isolated from reindeer, red deer and goat. The PCR assay was able to detect virus in nasal swabs 1-14 days after experimental infection of cattle and there was a good correlation when PCR was compared to virus isolation for the detection of BHV-1 in clinical field samples. Detection of BHV-1 in fetal bovine serum and semen samples was also successful. PCR detecting a broad range of BVDV, BDV and HCV was developed. Of six sets of primers selected from different parts of the pestivirus genome the best results were provided by a pair 324/326 from the highly conserved 5'-non-coding region which gave an amplification with all 129 isolates tested. This panel consisted of 79 isolates from cattle, 33 from pigs and 17 from sheep. Differentiation between viruses was achieved by cleavage of the PCR-amplified products (288 bp) with the restriction endonucleases AvaI and BglI. The BVDV products were cleaved by AvaI, HCV by BglI and AvaI. Both enzymes, AvaI and BglI, did not cut the BDV products. A nested polymerase chain reaction assay was developed for the detection of bovine respiratory syncytial virus (BRSV). Primers were selected from the gene encoding the F fusion protein. The sensitivity of PCR assay was 0.1 TCID50. No cross reaction was observed with nine heterologous respiratory viruses. PCR products of bovine and human RSV strains were discriminated using endonuclease ScaI, which specifically cleaved products of BRSV. PCR assay detected BRSV in nasal swabs collected from cattle in the acute stage of respiratory disease. In vitro amplification detected 31 positive samples of 35 while immunofluorescence only 23 samples.     

Serum levels of tumor necrosis factor-alpha in calves experimentally infected with Pasteurella haemolytica A1

The purpose of this study was to document the levels of tumor necrosis factor-alpha (TNF) in serum of calves experimentally infected intratracheally with Pasteurella haemolytica A1 and to determine if elevated TNF levels correlate with development of pneumonic pasteurellosis in the bovine. Serum samples were collected at sequential time periods from 0 h to 72 h post inoculation with P. haemolytica. TNF levels in those sera were measured by a cytotoxicity assay utilizing the TNF-sensitive WEHI 164 mouse fibrosarcoma cell line. Serum TNF levels in infected cattle began to rise at 2 h post inoculation, peaked at approximately 8 h, and decreased to near control levels by 72 h. There was extreme variability in serum TNF among the inoculated animals with levels varying from 120 pg ml-1 to 5000 pg ml-1 at 8 h post inoculation. These levels did not correspond with the degree of lung involvement. All inoculated calves developed lesions of pneumonic pasteurellosis characterized by fibrinous pleuritis with necrotizing, hemorrhagic pneumonia. These results suggest that TNF is probably a significant inflammatory mediator involved in the pathogenesis of bovine pneumonic pasteurellosis.     

A comparative evaluation of two sensitive serum neutralization tests for bovine herpesvirus-1 antibodies

The need for frequent injections and monitoring, the possibility of multiple gestations, and the higher cost compared to clomiphene citrate, prevents many clinicians from using human menopausal gonadotrophin (HMG) for ovulation induction. A sequential medication regimen, in which HMG is taken after clomiphene, overcomes these problems. We retrospectively compared per cycle fecundity and birth rates in 119 cycles of clomiphene-HMG, 524 cycles of clomiphene alone, 57 cycles of HMG alone, and 79 cycles of concurrent HMG and clomiphene in patients receiving intra-uterine insemination (IUI), who were free of endometriosis or tubal disease. Per cycle fecundity for clomiphene-HMG was 22% [95% confidence interval (CI) 12-34%], double that of clomiphene alone (11%) (95% CI 8-14%) (P < 0.01), and equal to HMG alone (18%) (95% CI 7-29%) or HMG and clomiphene together (19%) (95% CI 10-28%). The multiple birth rate for clomiphene-HMG (7/21) equalled that for HMG alone (3/12) and HMG and clomiphene together (3/8). The average number of ampoules of HMG required [follicle stimulating hormone (FSH) 75 mIU, luteinizing hormone (LH) 75 mIU] was decreased by 65% from 24.5 +/- 1.0 for HMG or HMG and clomiphene together to 8.6 +/- 0.3 for clomiphene-HMG (P < 0.001). Per cycle fecundity was identical when one, two or three ampoules of HMG per day were administered after clomiphene. We conclude that ovulation induction with sequential clomiphene-HMG results in fecundity double that of clomiphene alone and equal to HMG alone or concurrent with clomiphene, thereby reducing the requirement for HMG.     

Effects of bovine somatotrophin (bST) on ovarian function in post-partum beef cows

The effects of bovine somatotrophin (bST) on ovarian follicle development and function and associated gonadotrophin profiles during the first nine weeks post partum were investigated in beef cows. Thirty-two cows (Shorthorn x Galloway) in moderately low body condition (BC) at calving were fed to maintain BC thereafter. At Weeks 2, 4, 6 and 8 post partum, animals were injected with 320 mg bovine somatotrophin (bST) (T, treated; n = 17) or with the carrier oil only (C, control; n = 15). Ovulation occurred in 4 of 17 T cows and 0 of 15 C cows (P = 0.10) by nine week post partum. Treatment with bST did not affect the numbers of small (3-8 mm in diameter) or large (> 8 mm in diameter) follicles or the granulosa cell populations but enhanced the oestradiol (P < 0.05) and insulin-like growth factor-I (IGF-I) content (P < 0.01) of large follicles by nine weeks post partum. It did not significantly affect the testosterone concentrations of large follicles. Circulating concentrations of growth hormone (GH) and IGF-I were higher in T cows than in C cows (P < 0.001) but were unrelated to gonadotrophin profiles or gonadotrophin receptor concentrations in the follicles. At Week 8, plasma insulin concentrations were higher in T cows than in C cows both before (P < 0.05) and after (P < 0.05) glucose injection. It is concluded that GH may play an important role in mediating the effects of nutritional state on ovarian function during the post-partum period, possibly through alteration of intrafollicular IGF-I concentrations.     

Effects of different heavy-resistance exercise protocols on plasma beta-endorphin concentrations

To examine the changes of plasma beta-endorphin (beta-EP) concentrations in response to various heavy-resistance exercise protocols, eight healthy male subjects randomly performed each of six heavy-resistance exercise protocols, which consisted of identically ordered exercises carefully designed to control for the repetition maximum (RM) resistance (5 vs. 10 RM), rest period length (1 vs. 3 min), and total work (joules). Plasma beta-EP, ammonia, whole blood lactate and serum cortisol, creatine kinase, urea, and creatinine were determined preexercise, midexercise, immediately postexercise, and at various time points after the exercise session (5 min-48 h), depending on the specific blood variable examined. Only the high total work-exercise protocol [1 min rest, 10 RM load (H10/1)] demonstrated significant increases in plasma beta-EP and serum cortisol at midexercise and 0, 5, and 15 min postexercise. Increases in lactate were observed after all protocols, but the largest increases were observed after the H10/1 protocol. Within the H10/1 protocol, lactate concentrations were correlated (r = 0.82, P < 0.05) with plasma beta-EP concentrations. Cortisol increases were significantly correlated (r = 0.84) with 24-h peak creatine kinase values. The primary finding of this investigation was that beta-EP responds differently to various heavy-resistance exercise protocols. In heavy-resistance exercise, it appears that the duration of the force production and the length of the rest periods between sets are key exercise variables that influence increases in plasma beta-EP and serum cortisol concentrations. Furthermore the H10/1 protocol's significant challenge to the acid-base status of the blood, due to marked increases in whole blood lactate, may be associated with mechanisms modulating peripheral blood concentrations of beta-EP and cortisol.     

Effects of intramuscular injections of selenium and vitamin E on selenium-vitamin E deficiency in young pigs

Effects of intramuscular injections of selenium and vitamin E on lesions in pigs with selenium-vitamin E deficiency syndrome were determined in 2 factorial experiments, using a total 69 pigs. The pigs were fed a selenium-vitamin E deficient, 22.3% protein ration, supplemented with methionine, minerals, and vitamins. Weekly intramuscular injections of isotonic saline solution, vitamin E, selenium, or vitamin E and selenium were given to the respective treatment groups. Selenium-vitamin E deficiency lesions occurred only in pigs that were given saline injections. Weekly intramuscular injections of either selenium (as selenous acid buffered to pH (7.3) at the rate of 0.05 mg/kg of body weight or vitamin E at the rate of 20 IU/kg of body weight or the combination of selenium and vitamin E prevented cardiac and skeletal myodegeneration, hepatic necrosis, and death. Significant increases of serum aspartate aminotransferase activity values were noted in pigs with liver, heart, or skeletal muscle lesions, but these increases were not correlated with the extent of the lesions. Vascular lesions, epicardial and endocardial hemorrhages, and yellow discoloration of body fat were not features of this experimentally induced disease. These lesions may be related to factors other than the deficiency of selenium, vitamin E, or selenium and vitamin E in rations previously used in reported studies.     

Effects of folic acid and combinations of folic acid and vitamin B-12 on plasma homocysteine concentrations in healthy, young women

BACKGROUND: Elevated plasma homocysteine concentrations are considered to be a risk factor for vascular disease and fetal malformations such as neural tube defects. Recent studies have shown that plasma homocysteine can be lowered by folic acid in amounts corresponding to 1-2 times the recommended dietary allowance. Preliminary evidence indicates that vitamin B-12 may be beneficial when included in supplements or in a food-fortification regimen together with folic acid. OBJECTIVE: We aimed to compare the homocysteine-lowering potential of a folic acid supplement with that of 2 supplements containing different doses of vitamin B-12 in addition to folic acid. DESIGN: Female volunteers of childbearing age (n = 150) received a placebo for 4 wk followed by a 4-wk treatment with either 400 microg folic acid, 400 microg folic acid + 6 microg vitamin B-12, or 400 microg folic acid + 400 microg vitamin B-12. RESULTS: Significant reductions (P < 0.001) in plasma homocysteine were observed in all groups receiving vitamin treatment. The effect observed with the combination of folic acid + 400 microg vitamin B-12 (total homocysteine, -18%) was significantly larger than that with a supplement containing folic acid alone (total homocysteine, -11%) (P < 0.05). Folic acid in combination with a low vitamin B-12 dose (6 microg) affected homocysteine as well (-15%). CONCLUSIONS: These results suggest that the addition of vitamin B-12 to folic acid supplements or enriched foods maximizes the reduction of homocysteine and may thus increase the benefits of the proposed measures in the prevention of vascular disease and neural tube defects.     

Association of excess sulfur intake and an increase in hydrogen sulfide concentrations in the ruminal gas cap of recently weaned beef calves with polioencephalomalacia

During a 2-week period, 16 of 150 recently weaned calves developed signs of polioencephalomalacia (PEM). One calf was examined and treated at our veterinary teaching hospital and a necropsy was performed on a calf that died. During the peak of the outbreak, clinicians visited the ranch. Ruminal hydrogen sulfide (H2S) and blood thiamine concentrations were measured in 10 clinically normal penmates of PEM-affected calves. Ruminal H2S concentrations were high (> 0.695 mg/L [> 500 ppm]) in all cattle (mean, 12.19 mg/L [8,770 ppm]). All blood thiamine values were within the reference range. Within 12 hours after measurement of blood thiamine concentrations, 2 of the calves from which samples were obtained developed clinical signs of PEM. Dietary analysis revealed an estimated sulfur intake of 0.9% per calf on a dry-matter basis. Hay contributed most of this sulfur. In the investigation reported here, an outbreak of PEM was associated with high ruminal H2S concentrations and excess sulfur intake without evidence of thiamine deficiency.     

The effects of dietary soybean versus skim milk protein on plasma and hepatic concentrations of zinc in veal calves

We assessed the zinc status of veal calves that were fed milk replacers containing either skim milk protein as the sole source of protein or a mixture of skim milk protein and soybean protein. After the milk replacers had been fed for 26 wk, mean body weight gain was 3 kg lower for calves fed the skim milk plus soybean proteins; this decrease was not significant. Inclusion of dietary protein from soybeans versus milk protein alone reduced plasma concentrations of zinc by 43% and reduced hepatic concentrations of zinc by 81%. The impairment of zinc status that was induced by the inclusion of soybean protein was probably caused by its phytate component. The effect of soybean protein on zinc status was rather specific because plasma and hepatic concentrations of copper were unaffected. Despite the high concentration of zinc (142 mg/kg of dry matter) in the milk replacer that contained milk plus soybean proteins, calves displayed a shortage of zinc because their plasma and hepatic concentrations of zinc were significantly reduced.