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Abstract

Objective

To determine whether certification in a Milk and Dairy Beef Quality Assurance Program (MDBQAP) was associated with a reduced risk of having antibiotic residues in milk and to define specific management factors that may have predisposed dairy farms to having violative antibiotic residues in milk.

Sample Population

124 dairy farms in Michigan that had ≥ 1 violative residue in milk during 1993 and 248 randomly selected control farms in Michigan that did not have violative residues in milk during 1993.

Procedure

A pretested structured questionnaire was mailed to case and control farms. A conditional multivariate logistic regression model was developed to determine risk factors associated with having a violative antibiotic residue in milk.

Results

Certification in the MDBQAP did not significantly reduce the risk of having a violative antibiotic residue. Annual treatment of > 10% of a herd for metritis was associated with a reduced risk of having a violative residue. Evidence suggested that a routine request for a milk processor to perform residue testing was associated with a decreased risk of having had a violative antibiotic residue, but routine on-farm residue testing was associated with an increased risk of having had a residue.

Conclusions and Clinical Relevance

MDBQAP certification was associated, although not significantly, with a reduced risk of having violative antibiotic residues in milk. Risk factors significantly associated with violative antibiotic residues are addressed by various critical control points in the MDBQAP and may be indicators for strengths and weaknesses of MDBQAP. (Am J Vet Res 1999;60:1312–1316)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To evaluate the efficacy of prosthetic laryngoplasty with and without bilateral ventriculocordectomy for treatment of experimentally induced left laryngeal hemiplegia (LLH).

Animals

15 adult Standardbreds.

Procedure

Horses were allotted to 3 equal groups. Sham operation (group 1), prosthetic laryngoplasty (group 2), or prosthetic laryngoplasty with bilateral ventriculocordectomy (group 3) was performed after induction of LLH. Upper airway function testing was performed prior to left recurrent laryngeal neurectomy (LRLN), 14 days after LRLN, and 60 and 180 days after surgical treatment. Measurements were obtained at rest and at treadmill speeds corresponding to 75 and 100% of maximal heart rate. Videoendoscopy was performed at rest and during exercise in all horses prior to LRLN and 60 and 180 days after surgical treatment. Upper airway endoscopy was performed immediately after LRLN to document induction of grade-IV LLH. Also, horses in group 3 were endoscopically examined at 7, 14, 21, 28, and 120 days after surgical treatment to evaluate healing of the ventriculocordectomy sites.

Results

When horses were at rest, significant differences were not apparent between groups at any period or between periods for any measured variable. LRLN induced airway obstruction in all horses during exercise. In sham-operated horses, this obstruction was unaffected by time. In contrast, 60 and 180 days after surgical treatment, inspiratory flow limitations induced by LRLN were reversed in horses of groups 2 and 3. There were no significant differences between the 2 treatment groups. Endoscopy revealed the left arytenoid cartilage abducted beyond the intermediate position, but not touching the pharyngeal wall in all horses with a laryngeal prosthesis. After surgical treatment, 4 group-2 horses had filling of both ventricles with air during exercise. There was moderate to marked swelling of the ventriculocordectomy sites immediately after surgery, and this swelling resolved by 7 days after surgery. The ventriculocordectomy sites looked best at 14 and 180 days.

Conclusions

60 and 180 days after prosthetic laryngoplasty, upper airway function returned to pre-LRLN values in horses with experimentally induced LLH exercising at 100% of maximal heart rate. Combining ventriculocordectomy with prosthetic laryngoplasty does not further improve upper airway function in these horses. (Am J Vet Res 1996;57:1668–1673)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To document and determine changes in the mineral profiles of sera and mammary secretions from a population of periparturient mares.

Animals

18 clinically normal periparturient Arabian broodmares.

Procedure

Inductively coupled argon emission spectroscopy was used to measure Ca, Cu, Fe, K, Mg, Mn, Na, P, and Zn concentrations in sera and mammary secretions of periparturient mares. In addition, S was measured in mammary secretions.

Results

Serum concentrations of Ca, Cu, Fe, K, Mg, Na, P, and Zn remained constant throughout late pregnancy and the first 7 days of lactation. Compared with values on day 11 before foaling, mammary fluid concentrations of Ca, Cu, K, Mg, P, S, and Zn increased prior to parturition and all element concentrations, except Ca, decreased with the onset of lactation. In contrast, Na concentrations in mammary secretions decreased precipitously as parturition approached. Iron concentrations in mammary secretions remained relatively constant up to the time of parturition, decreased at parturition, and remained constant during lactation.

Conclusions and Clinical Relevance

Prior to foaling, increasing concentrations of Ca, Cu, K, Mg, P, S, or Zn in mammary secretions in concert with precipitous decreases in Na concentrations may provide a predictive index of impending parturition in the mare and a means of assessing fetal readiness for birth. (Am J Vet Res 1997;58:376–378)

Free access
in American Journal of Veterinary Research