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- Author or Editor: James P. Morehead x
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Abstract
Objective—To determine features of an early fetal loss (EFL) syndrome and evaluate potential risk factors for EFL in Thoroughbred broodmares on 4 farms in central Kentucky.
Design—Retrospective study.
Animals—288 pregnant broodmares.
Procedure—Year-2001 breeding records for 288 Thoroughbred broodmares were examined. Early fetal loss was defined as loss of a fetus that was viable at ≥ 40 days of gestation but was subsequently lost by 5 months of gestation.
Results—Overall 2001 EFL rate was 25% (73/288), median gestational age at time of fetal loss was 77 days, and median date of loss was May 7. Mares on 1 farm had significantly fewer fetal losses (5%) than mares on the other 3 farms (26 to 35%). Fetal losses were higher for maiden (42%) and barren (42%) mares than for foaling mares (18%). Fetal losses were greater in young than in older mares. Effects of broodmare farm, mare age, and reproductive status were all significant. Fetal losses were not associated with sire used for mating or stud farm.
Conclusions and Clinical Relevance—Greatest risk for EFL occurred during the period from late April to May (ie, in mares bred during February through March). Higher incidence of EFL in maiden and barren mares and lower incidence of EFL on 1 farm suggest management or environmental influences may have affected outcome. Risk factors that should be investigated include environmental differences among farms and differences in management procedures used for lactating versus nonlactating mares. (J Am Vet Med Assoc 2002;220:1828–1830)
Abstract
Objective—To compare endoscopic findings of the upper portion of the respiratory tract in Thoroughbred yearlings with their subsequent race records to determine whether subjective assessment of airway function may be used as a predictor of future racing performance.
Design—Retrospective study.
Animals—427 Thoroughbred yearlings.
Procedures—Endoscopic examination findings were obtained from the medical records and the videoendoscopic repository of the Keeneland 1996 September yearling sales. Racing records were requested for the yearlings through the end of their 4-year-old racing season (1997–2000). Twenty-nine measures of racing performance were correlated with endoscopic findings. Subjective arytenoid cartilage movement grades were determined, using a 4-point grading scale (grade 1 = symmetrical synchronous abduction of the arytenoid cartilages; grade 4 = no substantial movement of the left arytenoid cartilage).
Results—Of the 427 Thoroughbred yearlings included in this study, 364 established race records, and 63 did not. Opinions regarding suitability for purchase, meeting conditions of the sale, and the presence of epiglottic abnormalities had no significant association with racing performance. Arytenoid cartilage movement grades were significantly associated with many of the dependent variables. However, palatine abnormalities were not predictive of inferior racing performance.
Conclusions and Clinical Relevance—Thoroughbred yearlings with grade-1 and -2 arytenoid cartilage movements had significantly better racing performance as adults, compared with yearlings with grade- 3 arytenoid cartilage movements. In contrast, epiglottic and palatine abnormalities were not predictive of inferior racing performance. Therefore, evaluation of laryngeal function, but not epiglottic or palatine abnormalities, using the 4-point grading system, should be the major factor in developing recommendations for prospective buyers. (J Am Vet Med Assoc 2001;219: xxx–xxx)
Abstract
Objective—To determine whether administration of killed West Nile virus vaccine was associated with pregnancy loss among broodmares.
Design—Retrospective cohort study.
Animals—595 mares.
Procedure—Records of pregnant mares with known vaccination history from 4 farms were reviewed. Information obtained from 595 mares included mare's identification; farm; age; breed; reproductive status; last breeding date; date last known pregnant; vaccination date; age of conceptus at vaccination; vaccination during the early embryonic, early fetal, and late fetal periods; and whether an early embryonic death (EED), early fetal loss (EFL), or late fetal loss (LFL) occurred. The relationships between the dichotomous outcomes of loss (eg, EED, EFL, LFL) and independent categoric variables (eg, vaccination during the early embryonic, early fetal, or late fetal periods) were examined.
Results—Vaccination of pregnant mares during any period of gestation was not associated with increased incidence of pregnancy loss.
Conclusions and Clinical Relevance—Many mares are already pregnant at the onset of mosquito season, when mares are more likely to be vaccinated than at other times. Our findings provide evidence that vaccine administration will not compromise pregnancy in horses. (J Am Vet Med Assoc 2004;225:1894–1897)
Abstract
OBJECTIVE To evaluate 2- and 3-year-old and career race performance of Thoroughbred racehorse prospects with and without osteochondral fragmentation of the accessory carpal bone (ACB) identified on yearling presale radiographs.
DESIGN Retrospective, matched cohort study.
ANIMALS 47 nonlame Thoroughbreds with (exposed cohort) and 94 nonlame Thoroughbreds without (unexposed cohort) osteochondral fragmentation of ACB facture identified on yearling sales repository radiographs.
PROCEDURES Repository radiographic interpretation reports for September yearling sales of a large Kentucky auction house from 2005 through 2012 were reviewed, and race records were collected and analyzed. Race performance was compared between horses with and without ACB fracture chosen from the same sale to identify associations between racing performance and ACB fracture.
RESULTS No significant differences were identified between horses with or without ACB fracture in their incidence of starting a race as a 2- or 3-year-old and the number of races started, earnings, or earnings per start for 2- or 3-year-old or career race performance. There was no significant difference in performance between horses with or without concurrent carpal osteoarthritis, nor did performance differ between horses with ACB fracture alone and those with ACB fracture and other radiographic abnormalities found to be associated with poorer performance in previous studies.
CONCLUSIONS AND CLINICAL RELEVANCE ACB fracture with or without carpal osteoarthritic changes identified on repository radiographs of Thoroughbred yearlings was not associated with poorer racing performance or lower likelihood of starting a race as a 2- or 3-year-old, compared with outcomes for unaffected horses.
Abstract
OBJECTIVE
Assess femorotibial features in foals with and without medial femoral condyle (MFC) subchondral radiolucencies (SR+ and SR–).
METHODS
3 independent, sequential radiographic studies were performed. Study 1 retrospectively measured femorotibial morphological parameters in repository radiographs (SR– and SR+). Study 2 qualitatively compared drawings of intercondylar notch shape in postmortem radiographs (SR–). Study 3 prospectively measured femorotibial parameters in 1-month-old foals (SR–). In studies 1 and 3, 13 morphologic parameters were measured. Limb directional asymmetry was assessed in 2 age groups (< 7 or ≥ 7 months).
RESULTS
Study 1 (SR– group; n = 183 radiographs) showed increased femoral measurements with maturation, except the distal femoral intercondylar notch width (FINwal), which decreased. In contrast, in SR+ stifles (53 radiographs), 3 femoral parameters (MFC width [MFCwpf], MFC height, or FINwal) showed no changes. Tibial plateau width alone increased with maturation in both groups. Interobserver reliability was good to excellent. Study 2 (n = 53 radiographs) confirmed a distal FINw decrease in SR– foals. In study 1, left SR– stifles in greater than or equal to 7-month-old fillies had significantly larger femoral bicondylar width and FINw, while right SR+ stifles in fillies greater than or equal to 7 months had a significantly larger MFCw. In study 3 of 1-month-old foals (n = 94 SR– radiographs), the MFCw, femoral condyle bicondylar width, and lateral femoral condyle height were all greater on the left, whereas the intercondylar intereminence space width was larger on the right.
CLINICAL RELEVANCE
In SR+ stifles, the distal femur exhibited divergent maturation, indicating a wider MFC in the right stifle in older foals. As SR lesions are more common on the right, this suggests a potential association with MFC morphology.
