No evidence for a negative association between bovine leukemia virus status and fertility in Kansas beef herds: a cross-sectional study.
Am J Vet Res
; 84(5)2023 May 01.
Article
em En
| MEDLINE
| ID: mdl-36881499
ABSTRACT
OBJECTIVE:
Determine the association between bovine leukemia virus (BLV) status and fertility in beef cows. BLV-status was defined using 3 different testing strategies (ELISA-, quantitative polymerase chain reaction- [qPCR], and high proviral load [PVL]-status). Fertility was defined as the overall probability of pregnancy as well as the probability of becoming pregnant in the first 21 days of the breeding season. ANIMALS Convenience sample of 2,820 cows from 43 beef herds. PROCEDURES The association of BLV-status with the probability of becoming pregnant was evaluated with a multivariable logistic regression analysis that used pregnancy status as a binary outcome, herd nested within ranch as a random effect, and BLV-status (ELISA-, qPCR-, and PVL-status as separate models) and potential covariates (eg, age, Body Condition Score [BCS] category, and interactions) as fixed effects.RESULTS:
Raw data revealed that 55% (1,552/2,820) of cows were classified as BLV-positive by ELISA, and 95.3% (41/43) of herds had a least 1 ELISA-positive cow. Classification as BLV ELISA-positive was positively associated with the probability of being pregnant; however, when qPCR or PVL were used to classify BLV-status, there was no association with the probability of being pregnant. None of the methods of classifying BLV-status were associated with the probability of becoming pregnant in the first 21 days of the breeding season. CLINICAL RELEVANCE This study did not find evidence that testing beef cows for BLV-status using ELISA, qPCR, or a cut-off of 0.9 PVL and removing test-positive cows will improve cowherd fertility as described by the probability of becoming pregnant during the breeding season or becoming pregnant during the first 21 days of the breeding season.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Doenças dos Bovinos
/
Leucose Enzoótica Bovina
/
Vírus da Leucemia Bovina
Tipo de estudo:
Observational_studies
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Prevalence_studies
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Prognostic_studies
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Risk_factors_studies
Limite:
Animals
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Pregnancy
País/Região como assunto:
America do norte
Idioma:
En
Revista:
Am J Vet Res
Ano de publicação:
2023
Tipo de documento:
Article
País de publicação:
EEUU
/
ESTADOS UNIDOS
/
ESTADOS UNIDOS DA AMERICA
/
EUA
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UNITED STATES
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UNITED STATES OF AMERICA
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US
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USA