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  • Author or Editor: Munashe Chigerwe x
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Abstract

Objective—To determine whether vaccinating cows during late gestation against Mycoplasma bovis will result in adequate concentrations of M bovis–specific IgG1 in serum, colostrum, and milk.

Animals—78 dairy cows.

Procedures—Serum samples were obtained 60 and 39 days prior to expected parturition in vaccinated and control cows from a single herd. Serum and colostrum samples were also obtained at parturition. Milk samples were obtained 7 to 14 days after parturition. Samples were analyzed for anti–M bovis IgG1 concentrations.

Results—Prior to vaccination, control and vaccinated cows had similar anti–M bovis IgG1 concentrations. After initial vaccination and subsequent booster and at parturition, there was a significant difference between the 2 groups, with vaccinated cows having higher IgG concentrations. Colostrum from vaccinated cows had higher anti–M bovis IgG1 concentrations, compared with control cows; however, IgG1 concentrations in milk did not differ between the 2 groups.

Conclusions and Clinical Relevance—Vaccination of late-gestation cows resulted in increased concentrations of anti–M bovis IgG1 in colostrum. However, ingestion of colostrum by calves may not guarantee protection against M bovis infection.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine the amount of colostral IgG required for adequate passive transfer in calves administered colostrum by use of oroesophageal intubation and evaluate the impact of other factors on passive transfer of colostral immunoglobulins in calves.

Animals—120 Holstein bull calves.

Procedures—Calves were randomly assigned to specific treatment groups on the basis of volume of colostrum administered and age of calf at administration of colostrum. Colostrum was administered once by oroesophageal intubation. Equal numbers of calves received 1, 2, 3, or 4 L of colostrum, and equal numbers of calves received colostrum at 2, 6, 10, 14, 18, or 22 hours after birth. Serum samples were obtained from calves 48 hours after birth for IgG determination by radial immunodiffusion assay. Effects of factors affecting transfer of colostral immunoglobulins were determined by use of a stepwise multiple regression model and logistic regression models.

Results—A minimum of 153 g of colostral IgG was required for optimum colostral transfer of immunoglobulins when calves were fed3Lof colostrum at 2 hours after birth. Substantially larger IgG intakes were required by calves fed colostrum > 2 hours after birth.

Conclusions and Clinical Relevance—Feeding 100 g of colostral IgG by oroesophageal intubation was insufficient for adequate passive transfer of colostral immunoglobulins. At least 150 to 200 g of colostral IgG was required for adequate passive transfer of colostral immunoglobulins. Use of an oroesophageal tube for administration of 3 L of colostrum to calves within 2 hours after birth is recommended.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine the effect of time interval from birth to first colostrum feeding on colostrum intake and serum IgG concentration and the effect of varying colostral volume intake and colostral IgG concentration on the probability of failure of passive transfer (FPT) in bottle-fed calves.

Design—Randomized controlled study.

Animals—104 calves.

Procedures—Equal numbers of calves were randomly assigned to groups and fed 3 L of their dam's colostrum at 1, 2, 3, or 4 hours after birth by use of a nipple bottle. Calves were allowed to feed for 15 minutes, and intake was recorded. A second 3-L bottle feeding of colostrum was offered at 12 hours of age.

Results—17.2% of calves ingested 3 L of colostrum at the first feeding and 3 L at 12 hours of age. Calf age, up to 4 hours, had no significant effect on the calf's ability to ingest colostrum or on 48-hour serum IgG concentration. Colostral intake at 1, 2, 3, or 4 hours had no effect on intake at the second feeding. Probability of FPT in calves ingesting 3 L at both feedings was < 0.05.

Conclusions and Clinical Relevance—Allowing calves fed by nipple bottle to ingest as much colostrum as they can within 4 hours after birth and at 12 hours of age substantially reduced the probability of FPT. Bottle-fed calves that do not ingest 3 L of colostrum within the first 4 hours after birth should be targeted for oroesophageal intubation.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine sensitivity and specificity of a cow-side immunoassay kit for assessing IgG concentration in colostrum.

Design—Prospective study.

Animals—76 dairy and 11 beef cows of various parities.

Procedure—Colostrum from first, second, and third milkings and milk samples were collected, and IgG concentration was determined by means of radial immunodiffusion. The immunoassay was performed according to the manufacturer’s instructions, and sensitivity and specificity were calculated by comparing results of the immunoassay (positive vs negative) with results of immunodiffusion (< 50 g/L vs ≥ 50 g/L).

Results—135 colostrum or milk samples were collected. Mean ± SD colostral IgG concentrations, determined by means of radial immunodiffusion for dairy and beef cows were 65.4 ± 51.4 g/L and 114.8 ± 42.7 g/L, respectively. Mean IgG concentrations for first-, second-, and third-milking colostrum samples and for milk samples were 92 ± 49.0 g/L, 74.6 ± 45.1 g/L, 47.5 ± 32 g/L, and 6.8 ± 3.8 g/L, respectively. Sensitivity of the immunoassay (ie, percentage of samples with IgG concentration < 50 g/L with a positive immunoassay result) was 93%, and specificity (ie, percentage of samples with IgG concentration ± 50 g/L with a negative immunoassay result) was 76%.

Conclusions and Clinical Relevance—Results suggested that the immunoassay kit was an acceptable cow-side test to identify colostrum samples with IgG concentrations < 50 g/L. The immunoassay kit should be useful in screening colostrum for adequate IgG concentration before feeding to calves or storage. (J Am Vet Med Assoc 2005;227:129–131)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine associations between age, sex, breed, and month and year of admission and the diagnosis of lead toxicosis in cattle.

Design—Retrospective case-control study.

Sample Population—Records of all cattle evaluated at North American veterinary teaching hospitals during the years 1963 to 2002, which were available through the Veterinary Medical Database.

Procedures—Logistic regression was used to evaluate the associations between postulated risk factors and the occurrence of lead toxicosis in cattle and predict the occurrence of the diagnosis of lead toxicosis in cattle.

Results—413 cases of lead intoxication and 202,363 control cattle were identified and met the inclusion criteria. Cattle < 4 years of age were at increased risk for the diagnosis of lead intoxication relative to cattle ≥ 4 years of age. Cattle ≥ 2 months and < 6 months of age had the greatest risk for lead intoxication (odds ratio, 12.3). Angus cattle were at greater risk for toxicosis (odds ratio, 1.95), compared with other breeds. The risk of lead toxicosis was greater before 1985 (odds ratio, 1.94) than the risk thereafter. The risk of lead toxicosis diagnosis was greatest in the months of May, June, July, and August.

Conclusions and Clinical Relevance—Lead toxicosis in cattle was associated with age < 4 years and the Angus breed. A seasonal pattern existed with peak occurrence in the late spring and summer. The occurrence of lead toxicosis has declined over time.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine sensitivity and specificity of 4 methods to assess colostral IgG concentration in dairy cows and determine the optimal cutpoint for each method.

Design—Cross-sectional study.

Animals—160 Holstein dairy cows.

Procedures—171 composite colostrum samples collected within 2 hours after parturition were used in the study. Test methods used to estimate colostral IgG concentration consisted of weight of the first milking, 2 hydrometers, and an electronic refractometer. Results of the test methods were compared with colostral IgG concentration determined by means of radial immunodiffusion. For each method, sensitivity and specificity for detecting colostral IgG concentration < 50 g/L were calculated across a range of potential cutpoints, and the optimal cutpoint for each test was selected to maximize sensitivity and specificity.

Results—At the optimal cutpoint for each method, sensitivity for weight of the first milking (0.42) was significantly lower than sensitivity for each of the other 3 methods (hydrometer 1, 0.75; hydrometer 2, 0.76; refractometer, 0.75), but no significant differences were identified among the other 3 methods with regard to sensitivity. Specificities at the optimal cutpoint were similar for all 4 methods.

Conclusions and Clinical Relevance—Results suggested that use of either hydrometer or the electronic refractometer was an acceptable method of screening colostrum for low IgG concentration; however, the manufacturer-defined scale for both hydrometers overestimated colostral IgG concentration. Use of weight of the first milking as a screening test to identify bovine colostrum with inadequate IgG concentration could not be justified because of the low sensitivity.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine the mineral composition and anatomic location of urinary calculi and to investigate sex and reproductive status as predisposing factors for development of urolithiasis in potbellied pigs.

Design—Retrospective case series

Samples—Urinary calculi from 50 purebred and crossbred potbellied pigs.

Procedures—Laboratory records for urinary calculi of potbellied pigs submitted to the University of California-Davis Stone Laboratory from 1982 through 2012 were reviewed. Mineral composition of calculi was determined by polarized light microscopy, infrared spectroscopy, and, in some cases, x-ray diffractometry.

Results—Of the 48 urinary calculi analyzed by infrared spectroscopy, 21 (44%) were composed primarily of amorphous magnesium calcium phosphate; another 9 (19%) were primarily composed of calcium phosphate in the form of apatite. Of 50 urinary calculi, 22 (44%), 14 (28%), 10 (20%), 3 (6%), and 1 (2%) were removed from the urinary bladder only, urethra, both urinary bladder and urethra, urine, and renal pelvis, respectively. Sex of 6 potbellied pigs was not recorded. For 44 urinary calculi, 41 (93%) were from males (11 sexually intact males and 30 castrated) and 3 (7%) were from females (2 sexually intact females and 1 spayed). Among males, 73% (30/41) of submissions were from castrated males.

Conclusions and Clinical Relevance—In contrast to results from studies in commercial pigs, the most common composition of urinary calculi identified in purebred and crossbred potbellied pigs was amorphous magnesium calcium phosphate. Potential predisposing factors for urolithiasis in potbellied pigs may be similar to those for urolithiasis in commercial pigs. These include diet, urinary tract infections, and sex. Thus, prevention of urolithiasis should target these potential predisposing factors.

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in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE

To characterize injuries and describe medical management and clinical outcomes of goats, sheep, and pigs treated at a veterinary medical teaching hospital for burn injuries sustained during wildfires.

ANIMALS

Goats (n = 9), sheep (12), and pigs (7) that sustained burn injuries from wildfires.

PROCEDURES

Medical records were searched to identify goats, sheep, and pigs that had burn injuries associated with California wildfires in 2006, 2015, and 2018. Data regarding signalment, physical examination findings, treatments, clinical outcomes, time to discharge from the hospital, and reasons for death or euthanasia were recorded.

RESULTS

The eyes, ears, nose, mouth, hooves, perineum, and ventral aspect of the abdomen were most commonly affected in both goats and sheep. In pigs, the ventral aspect of the abdomen, distal limb extremities, ears, and tail were most commonly affected. The median (range) time to discharge from the hospital for goats and pigs was 11 (3 to 90) and 85.5 (54 to 117) days, respectively. One of 9 goats, 12 of 12 sheep, and 5 of 7 pigs died or were euthanized. Laminitis and devitalization of distal limb extremities were common complications (13/28 animals) and a common reason for considering euthanasia in sheep and pigs.

CONCLUSIONS AND CLINICAL RELEVANCE

Burn injuries in small ruminants and pigs required prolonged treatment in some cases. Results suggested prognosis for survival may be more guarded for sheep and pigs with burn injuries than for goats; however, further research is needed to confirm these findings.

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in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE To compare the pharmacokinetics of 2 commercial florfenicol formulations following IM and SC administration to sheep.

ANIMALS 16 healthy adult mixed-breed sheep.

PROCEDURES In a crossover study, sheep were randomly assigned to receive florfenicol formulation A or B at a single dose of 20 mg/kg, IM, or 40 mg/kg, SC. After a 2-week washout period, each sheep was administered the opposite formulation at the same dose and administration route as the initial formulation. Blood samples were collected immediately before and at predetermined times for 24 hours after each florfenicol administration. Plasma florfenicol concentrations were determined by high-performance liquid chromatography. Pharmacokinetic parameters were estimated by noncompartmental methods and compared between the 2 formulations at each dose and route of administration.

RESULTS Median maximum plasma concentration, elimination half-life, and area under the concentration-time curve from time 0 to the last quantifiable measurement for florfenicol were 3.76 μg/mL, 13.44 hours, and 24.88 μg•h/mL, respectively, for formulation A and 7.72 μg/mL, 5.98 hours, and 41.53 μg•h/mL, respectively, for formulation B following administration of 20 mg of florfenicol/kg, IM, and 2.63 μg/mL, 12.48 hours, and 31.63 μg•h/mL, respectively, for formulation A and 4.70 μg/mL, 16.60 hours, and 48.32 μg•h/mL, respectively, for formulation B following administration of 40 mg of florfenicol/kg, SC.

CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that both formulations achieved plasma florfenicol concentrations expected to be therapeutic for respiratory tract disease caused by Mannheimia haemolytica or Pasteurella spp at both doses and administration routes evaluated.

Full access
in American Journal of Veterinary Research