Objective—To determine whether kinematic changes
induced by heel pressure in horses differ from those
induced by toe pressure.
Animals—10 adult Quarter Horses.
Procedure—A shoe that applied pressure on the
cuneus ungulae (frog) or on the toe was used.
Kinematic analyses were performed before and after 2
levels of frog pressure and after 1 level of toe pressure.
Values for stride displacement and time and joint angles
were determined from horses trotting on a treadmill.
Results—The first level of frog pressure caused
decreases in metacarpophalangeal (fetlock) joint extension
during stance and increases in head vertical movement
and asymmetry. The second level of frog pressure
caused these changes but also caused decreases in
stride duration and carpal joint extension during stance
as well as increases in relative stance duration. Toe pressure
caused changes in these same variables but also
caused maximum extension of the fetlock joint to occur
before midstance, maximum hoof height to be closer to
midswing, and forelimb protraction to increase.
Conclusion and Clinical Relevance—Decreased fetlock
joint extension during stance and increased head
vertical movement and asymmetry are sensitive indicators
of forelimb lameness. Decreased stride duration,
increased relative stance duration, and decreased
carpal joint extension during stance are general but
insensitive indicators of forelimb lameness. Increased
forelimb protraction, hoof flight pattern with maximum
hoof height near midswing, and maximum fetlock joint
extension in cranial stance may be specific indicators
of lameness in the toe region. Observation of forelimb
movement may enable clinicians to differentiate lameness
of the heel from lameness of the toe. (Am J Vet Res 2000;61:612-619)
OBJECTIVE To compare blood flow velocities of the portal vein (PV) and caudal vena cava (CVC) measured by use of pulsed-wave Doppler ultrasonography in clinically normal dogs and dogs with primary immune-mediated hemolytic anemia (IMHA).
ANIMALS 11 client-owned dogs admitted to a veterinary teaching hospital for management of primary IMHA and 21 staff- or student-owned clinically normal dogs.
PROCEDURES Flow velocities in the PV and CVC at the porta hepatis were evaluated in conscious unsedated dogs with concurrent ECG monitoring; evaluations were performed before dogs with IMHA received heparin or blood transfusions. Three measurements of peak velocity at end expiration were obtained for each vessel, and the mean was calculated. Results were compared between IMHA and control groups.
RESULTS Mean ± SD blood flow velocity in the CVC differed between control (63.0 ± 18.6 cm/s) and IMHA (104 ± 36.9 cm/s) groups. Variance in dogs with IMHA was significantly greater than that for the clinically normal dogs. No significant difference in blood flow velocity in the PV was detected between IMHA and control dogs.
CONCLUSIONS AND CLINICAL RELEVANCE Higher blood flow velocities were detected by use of pulsed-wave Doppler ultrasonography in the CVC of dogs with naturally occurring IMHA and may be used to predict anemia in patients suspected of having IMHA.
Objective—To identify hind limb and pelvic kinematic
variables that change in trotting horses after induced
lameness of the distal intertarsal and tarsometatarsal
joints and after subsequent intra-articular administration
Animals—8 clinically normal adult horses.
Procedure—Kinematic measurements were made
before and after transient endotoxin-induced lameness
of the distal intertarsal and tarsometatarsal joints and
after intra-articular administration of anesthetic.
Fourteen displacement and joint angle (metatarsophalangeal
[fetlock] and tarsal joints) measurements were
made on the right hind limb, sacrum, and the right and
left tubera coxae. Kinematic measurements were compared
by general linear models, using a repeated measures
ANOVA. Post hoc multiple comparisons between
treatments were evaluated with a Fisher least squared
difference test at α = 0.05.
Results—After lameness induction, fetlock and tarsal
joint extension during stance decreased, fetlock joint
flexion and hoof height during swing increased, limb protraction
decreased, and vertical excursion of the tubera
coxae became more asymmetric. After intra-articular
administration of anesthetic, limb protraction returned to
the degree seen before lameness, and vertical excursion
of the tubera coxae became more symmetric.
Conclusions and Clinical Relevance—Increased
length of hind limb protraction and symmetry of tubera
coxae vertical excursion are sensitive indicators of
improvement in tarsal joint lameness. When evaluating
changes in tarsal joint lameness, evaluating the horse
from the side (to assess limb protraction) is as important
as evaluating from the rear (to assess pelvic symmetry).
(Am J Vet Res 2000;61:1031–1036)
OBJECTIVE To determine herd-level risk factors for bovine respiratory disease (BRD) in nursing beef calves.
DESIGN Matched case-control study.
SAMPLE 84 cow-calf operations in Nebraska, North Dakota, and South Dakota.
PROCEDURES Case herds were herds that treated at least 5% of the calf crop for BRD prior to weaning. Control herds were herds that treated < 0.5% of the calf crop for BRD prior to weaning. Each case herd was matched with 2 control herds on the basis of veterinary practice and enrollment year. Herd owners or managers were interviewed by telephone, and characteristics and practices associated with case status were determined by multivariable conditional logistic regression.
RESULTS 30 case herds and 54 control herds were evaluated. Increasing herd size, frequent pasture movement for intensive grass management (intensive grazing), and use of estrus-synchronization programs were significantly associated with herd status. The odds of being a case herd for herds with 150 to 499 cows was 7.9 times and that for herds with ≥ 500 cows was 12 times, compared with the odds of being a case herd for herds with < 150 cows. The odds of being a case herd for herds that used intensive grazing was 3.3 times that for herds that did not use intensive grazing. The odds of being a case herd for herds that used an estrus-synchronization program was 4.5 times that for herds that did not use an estrus-synchronization program.
CONCLUSIONS AND CLINICAL RELEVANCE Management practices can be associated with an increase in the BRD incidence in nursing beef calves. Modification of management practices may decrease BRD incidence in nursing calves for herds in which it is a problem.
OBJECTIVE To describe use of whole-genome sequencing (WGS) and evaluate the apparent sensitivity and specificity of antemortem tuberculosis tests during investigation of an unusual outbreak of Mycobacterium bovis infection in a Michigan dairy herd.
PROCEDURES All cattle in the index dairy herd were screened for bTB with the caudal fold test (CFT), and cattle ≥ 6 months old were also screened with a γ-interferon (γIFN) assay. The index herd was depopulated along with all barn cats and a dog that were fed unpasteurized milk from the herd. Select isolates from M bovis–infected animals from the index herd and other bTB-affected herds underwent WGS. Wildlife around all affected premises was examined for bTB.
RESULTS No evidence of bTB was found in any wildlife examined. Within the index herd, 53 of 451 (11.8%) cattle and 12 of 21 (57%) cats were confirmed to be infected with M bovis. Prevalence of M bovis–infected cattle was greatest among 4- to 7-month-old calves (16/49 [33%]) followed by adult cows (36/203 [18%]). The apparent sensitivity and specificity were 86.8% and 92.7% for the CFT and 80.4% and 96.5% for the γIFN assay when results for those tests were interpreted separately and 96.1% and 91.7% when results were interpreted in parallel. Results of WGS revealed that M bovis–infected barn cats and cattle from the index herd and 6 beef operations were infected with the same strain of M bovis. Of the 6 bTB-affected beef operations identified during the investigation, 3 were linked to the index herd only by WGS results; there was no record of movement of livestock or waste milk from the index herd to those operations.
CONCLUSIONS AND CLINICAL RELEVANCE Whole-genome sequencing enhanced the epidemiological investigation and should be used in all disease investigations. Performing the CFT and γIFN assay in parallel improved the antemortem ability to detect M bovis–infected animals. Contact with M bovis–infected cattle and contaminated milk were major risk factors for transmission of bTB within and between herds of this outbreak.