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  • Author or Editor: Rodrigo C. Bicalho x
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Objective—To develop a parsimonious statistical model to predict incidence of lameness in the subsequent lactation by use of data collected at cessation of lactation in dairy cows.

Animals—574 cows.

Procedures—At cessation of lactation during hoof trimming, body condition score (BCS), visual locomotion score, digital cushion thickness (DCT), and digital lesions were assessed.

Results—140 (24%) cows were treated for claw horn disruption lesions (CHDLs) at cessation of lactation (114 with sole ulcers [pododermatitis circumscripta] and 26 with white line disease). The BCS was highly associated with DCT. Cows with CHDLs at cessation of lactation had significantly lower DCT, compared with other cows. All 3 logistic regression models predicted the incidence of CHDLs in the subsequent lactation with good accuracy; the area under the receiver operating characteristic curves was 0.76, 0.76, and 0.77 for the first, second, and third logistic regression models, respectively.

Conclusion and Clinical Relevance—Evaluation of 3 logistic regression models indicated that lameness could be predicted with good accuracy by use of all 3. The ability to predict lameness will facilitate the implementation of lameness prevention strategies by targeting specific cows.

Full access
in American Journal of Veterinary Research


Objective—To isolate and characterize bacteriophages with strong in vitro lytic activity against various pathogenic Pseudomonas aeruginosa strains isolated from dogs with ocular infections.

Sample—26 genetically distinct P aeruginosa isolates.

ProceduresP aeruginosa strains were derived from dogs with naturally acquired ulcerative keratitis. From a large-scale screening for bacteriophages with potential therapeutic benefit against canine ocular infections, 2 bacteriophages (P2S2 and P5U5) were selected; host ranges were determined, and phage nucleic acid type and genetic profile were identified via enzymatic digestion. Electron microscopy was used to characterize bacteriophage ultrastructure. Bacteriophage temperature and pH stabilities were assessed by use of double-layer agar overlay titration. A cocultivation assay was used to evaluate the effect of the bacteriophages on bacterial host growth.

Results—P5U5 was active against all P aeruginosa isolates, whereas P2S2 formed lytic plaques on plates of 21 (80.8%) isolates. For each bacteriophage, the genomic nucleic acid was DNA; each was genetically distinct. Ultrastructurally, P2S2 and P5U5 appeared likely to belong to the Podoviridae and Siphoviridae families, respectively. The bacteriophages were stable within a pH range of 4 to 12; however, titers of both bacteriophages decreased following heating for 10 to 50 minutes at 45° or 60°C. Growth of each P aeruginosa isolate was significantly inhibited in coculture with P2S2 or P5U5; the dose response was related to the plaque-forming unit-to-CFU ratios.

Conclusions and Clinical Relevance—Bacteriophages P2S2 and P5U5 appear to be good candidates for phage treatment of infection caused by pathogenic P aeruginosa in dogs.

Full access
in American Journal of Veterinary Research


Objective—To characterize clinical ocular disease, viral shedding, and serologic response associated with primary canine herpesvirus-1 (CHV-1) ocular infection in naïve adult dogs.

Animals—12 specific pathogen-free adult Beagles.

Procedures—Dogs were topically inoculated in the right eye with CHV-1 (infection group; n = 8) or virus-free medium (control group; 4). Dogs were inoculated with or without corneal microtrephination and subconjunctivally administered corticosteroids. Conjunctiva, buffy coat, and serum samples for real-time PCR assay, virus isolation, and serum neutralization (SN) antibody titers were collected until postinfection day (PID) 224, and general physical and ophthalmologic examinations were performed.

Results—Dogs in the infection group developed bilateral, mild to moderate conjunctivitis that reached maximal intensity on PIDs 7 to 10. Ocular viral shedding was detected in all dogs in the infection group between PIDs 3 and 10. Infected dogs developed CHV-1 SN antibody titers, beginning at PID 7 and peaking on PID 21. All buffy coat PCR assay results were negative. Corneal microtrephination and subconjunctival corticosteroid administration did not significantly affect clinical disease or viral shedding. Following recovery from primary infection, dogs remained clinically normal, did not shed virus, and had slowly decreasing SN antibody titers. Dogs in the control group did not develop conjunctivitis, shed virus, or develop CHV-1 SN antibody titers.

Conclusions and Clinical Relevance—Primary ocular infection of adult dogs with CHV-1 was associated with self-limiting conjunctivitis and ocular viral shedding, which was evident in the absence of clinically detectable keratitis or systemic disease. Features of this infection resembled herpes simplex virus primary ocular infection in humans.

Full access
in American Journal of Veterinary Research



To determine whether body weight, age, or sex was associated with ultrasonographically determined adrenal gland thickness (AT) in dogs with non-adrenal gland illness.


Retrospective cross-sectional study.


266 dogs (22 sexually intact and 119 castrated males and 19 sexually intact and 106 spayed females representing 12 breeds) with non-adrenal gland illness.


Thickness of the caudal pole of the left and right adrenal glands was measured on longitudinal ultrasonographic images. Dogs were stratified into age and body weight categories to investigate associations with AT.


AT was significantly lower in dogs that weighed ≤ 12 kg (26.4 lb) than in dogs that weighed > 12 kg and left AT increased with age. Both left and right AT were larger in male than in female dogs that weighed > 12 to ≤ 20 kg, and left AT was larger in male than in female dogs that weighed > 20 to ≤ 30 kg.


Results suggested that body weight, age, and sex were significantly associated with AT, indicating that these variables should be considered when evaluating AT in dogs with non-adrenal gland illness and when developing reference intervals for AT in dogs. Further, findings indicated that dogs with non-adrenal gland illness that weigh ≤ 12 kg should have an AT no greater than 0.62 cm, whereas dogs that weigh > 12 kg should have an AT no greater than 0.72 cm.

Full access
in Journal of the American Veterinary Medical Association


Objective—To evaluate effect of twin birth calvings on milk production, reproductive performance, and survival of lactating cows.

Design—Retrospective observational cohort study.

Animals—33,868 cows from 20 farms.

Procedures—Data on age at calving for primiparous cows and mature equivalent milk yield for multiparous cows, assistance at calving, stillbirths, twin births, gestation duration, pregnancy at the end of the data collection period, and culling-death for all cows were extracted from farm computer records and used for statistical analysis.

Results—Prevalence of twin parturitions was 1.3% (159/12,050) and 6.5% (1,410/21,818) for primiparous and multiparous cows, respectively. Primiparous and multiparous cows with singletons produced more milk than cows with live twins or at least 1 dead twin (primiparous, 33.1 vs 31.9 vs 31.2; multiparous, 36.5 vs 35.7 vs 35.0). Multiparous cows with dead twins produced less milk than cows with live twins. Compared with dams with singleton birth, cows with twins were 0.78 times as likely to conceive and 1.42 times as likely to die or be culled. Cows with dead twins also had increased time to conception, compared with live twins.

Conclusions and Clinical Relevance—Twin birth was associated with decreased survival, milk production, and reproductive performance. Having at least 1 dead twin was even more detrimental than having live twins and resulted in decreased milk production and reproductive performance of lactating cows.

Full access
in Journal of the American Veterinary Medical Association