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SUMMARY

We quantified the effect of passive immune status on pre- and postweaning health and growth performance of calves raised in a beef production environment. Blood samples were collected at postpartum hour 24 from 263 crossbred calves for determination of plasma protein (pp) and serum IgG concentrations. Serum IgG concentration was classified as adequate (> 1,600 mg/dl), marginal (800 to 1,600 mg/dl), or inadequate (< 800 mg/dl). Plasma protein concentration was classified as adequate (≥ 4.8 g/dl) or inadequate (< 4.8 g/dl). Morbidity and mortality events in the study population were monitored from birth to weaning, and after weaning throughout the feeding period. The lowest concentrations of serum IgG and pp were observed among calves that experienced morbidity or mortality prior to weaning. Calves that experienced morbidity in the feedlot had lower 24-hour pp values, but had IgG concentration similar to that in calves that were not observed to be ill during the feeding period. Calves classified as having inadequate IgG concentration were at greater risk of preweaning mortality (odds ratio [or] = 5.4), neonatal morbidity (or = 6.4), and preweaning morbidity (or = 3.2), compared with calves classified as having adequate IgG concentration at 24 hours. Calves classified as having inadequate pp concentration at 24 hours had a greater risk of morbidity (or = 3.0) and respiratory tract morbidity (or = 3.1) while in the feedlot, compared with calves classified as having adequate pp concentration. The effects of 24-hour passive immune status on calf growth were indirect through effects on morbidity outcomes. Morbidity during the first 28 days of life was associated with a 16-kg lower expected weaning weight. Respiratory morbidity in the feedlot resulted in a 0.04-kg lower expected mean daily gain. Thus, passive immune status at postpartum hour 24 was an important determinant of health before and after weaning, and was indirectly associated with calf growth during the same periods.

Free access
in American Journal of Veterinary Research

SUMMARY

In an attempt to identify important predictors of failure of passive immunoglobulin transfer (< 800 mg of IgG/dl), identify calves with failure of passive immunoglobulin transfer, and determine the effects of a colostrum supplement, blood samples were collected from 263 calves at postpartum hours 10 and 24. Calves of dams diagnosed with mastitis had lower mean plasma protein and IgG concentrations at 10 (P < 0.05) and 24 (P < 0.01) hours. Plasma protein and IgG concentrations were similar for single and twin calves at 10 hours, but IgG concentration at 24 hours was higher (P < 0.01) in twin calves. Calves born to dams that had dystocia had numerically lower mean plasma protein and IgG concentrations than did calves born to dams that had normal delivery. However, observed differences were small and, after adjustment for other important factors, these differences were not significant. Age of dam was associated with plasma protein (P < 0.05) and IgG (P < 0.10) concentrations at 10 hours, but had no effect at 24 hours. Plasma protein and IgG concentrations decreased as calves were born later in the calving season, although the association of birth date with IgG concentration at 24 hours was marginal (P = 0.07). Calf sex, dam body condition score, and birth weight were not related to plasma protein or IgG values. The sensitivity and specificity of a cutoff value of 4.8 g of protein/dl of plasma, measured at 10 hours, for diagnosing failure of passive immunoglobulin transfer at 10 hours were 78 and 94%, and for diagnosing failure of passive immunoglobulin transfer at 24 hours were 88 and 73%, respectively. A colostrum supplement administered to calves with low plasma protein concentration at 10 hours had no effect on plasma protein or IgG values at 24 hours or on pre-weaning morbidity and mortality.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To determine the effects of florfenicol injection on the meat characteristics of the cervical muscles in cattle.

Animals—100 steers (mean weight, 380 kg).

Procedure—In 50 calves, florfenicol (25 ml, twice) was injected into the cervical muscles of 1 side of the neck, and saline (0.9% NaCl) solution (25 ml, twice) was injected into the cervical muscles of the other side of the neck. In the remaining 50 calves, florfenicol was injected into the cervical muscles of 1 side of the neck, and nothing was injected into the cervical muscles of the other side of the neck. Animals were slaughtered 132 days later, and samples of the cervical muscles were submitted for histologic evaluation and measurement of shear forces.

Results—2 injection sites used in the present study had extensive lesions, and both of these were sites where florfenicol had been injected. However, histologic scores for the florfenicol injection sites were not significantly different from scores for the contralateral saline solution injection sites and uninjected control sites. In addition, shear force values were not significantly different between sites in which florfenicol had been injected and the contralateral sites.

Conclusion and Clinical Relevance—Results suggest that few reactions should be expected with injection of florfenicol into the cervical muscles in steers and that reactions that do occur will consist mainly of fibrosis and infiltration of adipose tissue. However, shear force values, a measure of tenderness of the meat, should not be affected. (Am J Vet Res 2002;63:64–68)

Full access
in American Journal of Veterinary Research

Summary

Six steer calves, surgically fitted with a permanent cannula in the rumen, omasoabomasal orifice, abomasum, and duodenum were used to determine total digesta flow and volatile fatty acid (vfa) concentration at various points in the digestive tract. The omasoabomasal cannula had a flexible nylon sleeve that could be exteriorized through the abomasal cannula to collect omasal effluent.

Three experiments were conducted: 95% concentrate fed at maintenance (2,670 g of organic matter intake/d); 95% concentrate fed ad libitum (3,484 g of organic matter intake/d); and brome hay fed ad libitum (2,927 g of organic matter intake/d). Calves were offered the diet in 12 portions daily. Each experiment included a 14-day adaptation period and a 2-day sample collection period during which chromic oxide was used as a digesta flow marker. In all 3 experiments, vfa concentration was greatest in the rumen sample (84 to 109 mM), intermediate in the omasal sample (32 to 40 mM), and lowest in the duodenal sample (7 to 14 mM, P < 0.01). Total fluid flow at the duodenum was 13 to 18 L/d greater than flow at the omasum (P < 0.10). Omasal vfa flow was twofold greater than duodenal vfa flow (P < 0.05). There was a net fluid increase and net disappearance of vfa across the abomasum. The cannulation technique was useful for repeated collection of omasal effluent for at least 3 months.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To investigate eating and drinking behaviors and their association with bovine respiratory disease complex (BRDC) and to evaluate methods of diagnosing BRDC.

Animals—170 newly arrived calves at a feedlot.

Procedure—Eating and drinking behaviors of calves were recorded at a feedlot. Calves with clinical signs of BRDC were removed from their pen and classified retrospectively as sick or not sick on the basis of results of physical and hematologic examinations. Pulmonary lesions of all calves were assessed at slaughter.

Results—Calves that were sick had significantly greater frequency and duration of drinking 4 to 5 days after arrival than calves that were not sick. Sick calves had significantly lower frequency and duration of eating and drinking 11 to 27 days after arrival but had significantly greater frequency of eating 28 to 57 days after arrival than calves that were not sick. Calves at slaughter that had a higher percentage of lung tissue with pneumonic lesions had significantly lower frequency and duration of eating 11 to 27 days after arrival but had significantly higher frequency and duration of eating 28 to 57 days after arrival. Agreement for calves being sick and having severe pulmonary lesions at slaughter was adequate. Agreement for calves being removed and having pulmonary lesions at slaughter was low.

Conclusions and Clinical Relevance—Eating and drinking behaviors were associated with signs of BRDC, but there was not an obvious predictive association between signs of BRDC in calves and eating and drinking behaviors. Fair to poor agreement was observed between antemortem and postmortem disease classification. (Am J Vet Res 2000;61:1163–1168)

Full access
in American Journal of Veterinary Research

Abstract

Objectives—To determine the effect of location for administration of clostridial vaccines on behavior, growth performance, and health of calves at a feedlot, the relative risk of calves developing an injection-site reaction or being misdiagnosed as having bovine respiratory disease complex (BRDC), and the percentage of subcutaneous injection-site reactions that were detectable on carcasses after the hides were removed.

Animal—170 newly arrived calves at a feedlot.

Procedure—Eating and drinking behaviors of calves during the initial 57 days after arrival were observed at a commercial feedlot, using an electronic monitoring system. Calves were assigned randomly to receive a clostridial vaccine (base of ear or neck). Data on reactions at the injection site were collected.

Results—Mean daily gain (MDG) for the initial 57 days did not differ significantly between treatments. Risk of being misdiagnosed as having BRDC was not associated with location for administration of vaccine. Calves vaccinated in the base of the ear were at higher risk of having an injection-site reaction at day 57 or at slaughter. Eighty-nine percent (95% confidence interval, 52 to 100%) of injection-site reactions in the neck could not be located on the carcasses after hides were removed. Calves vaccinated in the neck drank significantly fewer times per day during the first 57 days than calves vaccinated in the base of the ear.

Conclusions and Clinical Relevance—Location for administration of a clostridial vaccine did not significantly affect health, growth performance, or eating behavior. Most subcutaneous injection-site reactions were not detectable after the hide was removed. (Am J Vet Res 2000;61:1169–1172)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To describe patterns of seroconversion to bovine coronavirus (BCV) and shedding of BCV from the respiratory tract in feedlot cattle.

Animals—1,074 calves in feedlots in Ohio, Texas, and Nebraska.

Procedure—Nasal swab specimens were obtained at time of arrival (day 0) and at various times during the initial 28 days after arrival at feedlots. Specimens were tested for BCV, using an antigen-capture ELISA. Serum samples were obtained at time of arrival and again 28 days after arrival; sera were analyzed for antibodies to BCV, using an antibody-detection ELISA.

Results—Samples from 12 groups of cattle entering 7 feedlots during a 3-year period revealed that 78 of 1,074 (7.3%) cattle were shedding BCV (range, 0 to 35.9% within specific groups). At time of arrival, 508 of 814 (62.4%) cattle had low (< 50) or undetectable BCV antibody titers. Seroconversion to BCV during the initial 28 days after arrival was detected in 473 of 814 (58%) cattle tested (range, 20.3 to 84.1% within specific groups). In cattle shedding BCV from the nasal passages, 49 of 68 (72.1%) seroconverted, and 472 of 746 (63.3%) cattle that were not shedding the virus seroconverted.

Conclusions and Clinical Relevance—Bovine coronavirus can be detected in populations of feedlot cattle in the form of viral shedding as well as seroconversion to the virus. Although only a few cattle were shedding the virus at the time of arrival at a feedlot, most of the cattle seroconverted to BCV by 28 days after arrival. (Am J Vet Res 2000;61:1057–1061)

Full access
in American Journal of Veterinary Research

Summary

Cell extracts that were prepared from blood mononuclear leukocytes from 66 samples obtained from 6 clinically normal calves contained mean 2′,5′-oligoadenylate (2′,5′-oligo[A]) synthetase activity sufficient to synthesize 186 ± 82 pmol of 2′,5′-oligo(A)/h/106 cells. Calves had no measurable serum interferon (ifn) activity. Five calves were given im injections of 104, 105, 5 × 105, 106, and 107 U of bovine ifn-α1/kg of body weight at 2-week intervals. Five dosing sequences were used with a 5 × 5 Latin square design so that each calf received each dose once. Activity of 2′,5′-oligo(A) synthetase increased at 24 hours in response to all dosages of ifn and then declined following first-order kinetics, with an apparent half-life (t½) of 2.1 ± 0.5 days. The area under the concentration-time curve for 2′,5′-oligo(A) synthetase increased with dose of ifn more rapidly than did peak response. Serum ifn that was measured at 1-day intervals following administration of ifn was consistently measurable only at dosages above 106 U of ifn/kg. The t½ for circulating ifn was 12.4 ± 1.0 hours. Over all dosages, increases in 2′,5′-oligo(A) synthetase activity were measurable for 3.5 days longer than were increases in ifn following im injection of ifn. None of the calves developed detectable anti-ifn antibodies.

Free access
in American Journal of Veterinary Research

Objective

To determine whether booster vaccination with a multivalent clostridial bacterin-toxoid would affect the sudden death syndrome (SDS) mortality rate among feedlot cattle.

Design

Field trial.

Animals

83,115 cattle at a Nebraska feedlot.

Procedure

Cattle arriving at the feedlot underwent routine processing according to established protocol. All cattle received a sequentially numbered ear tag and a 2-ml dose of a multivalent bacterin-toxoid designed to protect cattle against Clostridium chauvoei, C septicum, C novyi, C sordellii, and C perfringens types C and D. Approximately 90 days prior to slaughter, growth promotants were implanted in all cattle, and cattle were allocated to a treatment or control group on the basis of the last digits of their ear tag numbers. Cattle in the treatment group received a second 2-ml dose of clostridial bacterin-toxoid; control cattle did not.

Results

Significant differences between groups in regard to crude, feeding pen, or SDS mortality rates were not detected. Sudden death syndrome mortality rate across both groups was 0.24%. If the SDS mortality rate in midwestern feedlot cattle was reduced ≥ 40% by booster vaccination with a multivalent clostridial bacterin-toxoid, this experiment included enough animals to have a 90% probability of detecting that difference.

Clinical Implications

Booster vaccination with a multivalent clostridial bacterin-toxoid does not affect SDS mortality rate among feedlot cattle. (J Am Vet Med Assoc 1997,211:749–753)

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine the association between respiratory tract infection with bovine coronavirus (BCV), treatment for respiratory tract disease, pulmonary lesions at slaughter, and average daily gain in cattle in feedlots.

Animals—837 calves in feedlots in Ohio and Texas.

Procedure—Nasal swab specimens were obtained from cattle at arrival in a feedlot (day 0) and at various times during the initial 28 days after arrival. Specimens were tested for BCV, using an antigencapture ELISA. Serum samples were obtained at arrival and again 28 days after arrival and tested for antibodies to BCV, using an antibody-detection ELISA. Information was collected regarding treatment for cattle with respiratory tract disease and average daily gain during the feeding period. Pulmonary lesions were evaluated at slaughter.

Results—Cattle shedding BCV from the nasal cavity and developing an antibody response against BCV were 1.6 times more likely to require treatment for respiratory tract disease than cattle that did not shed the virus or develop an immune response against BCV. Additionally, cattle that shed BCV from the nasal cavity were 2.2 times more likely to have pulmonary lesions at slaughter than cattle that did not shed the virus. The BCV shedding or seroconversion status did not affect average daily gain.

Conclusions and Clinical Relevance—Bovine coronavirus infects feedlot cattle and is associated with an increased risk for cattle developing respiratory tract disease and pulmonary lesions. Development of appropriate control measures could help reduce the incidence of respiratory tract disease. (Am J Vet Res 2000;61:1062–1066)

Full access
in American Journal of Veterinary Research