Short communication: Repeat breeder cows with fluid in the uterine lumen had poorer fertility.

The objective of the present study was to test the association between the presence of fluid in uterine lumen and the fertility of repeat breeder cows (RBC). Grazing Holstein cows that were clinically normal and were not pregnant after at least 3 consecutive inseminations were defined as RBC and included in the study (n = 358). A cut-point ≥2 mm of uterine lumen visible by ultrasonography was used as indicative of the presence of fluid in the uterus. The effect of this fluid on the fertility of RBC was assessed by mixed logistic regression. Twenty percent of the RBC had ≥2 mm of fluid in their uterus, and this finding was associated with a marked reduction in the odds of conception (odds ratio = 0.46). Additional intrauterine sampling revealed that 24.0% of RBC showed signs of subclinical endometritis [≥5% neutrophils in endometrial cytology (SCE)]. However, we found no agreement between the finding of uterine fluid and the diagnosis of SCE (kappa coefficient = 0.03, 95% confidence interval = -0.07 to 0.14). In conclusion, the presence of fluid (≥2 mm) in uterine lumen, detected by ultrasonography, was associated with lower fertility in RBC, but was not related to the diagnosis of SCE. Thus, ultrasonographic evaluation is an important tool to assist in assessment of RBC.

Technical note: Evaluation of a system for monitoring individual feeding behavior and activity in beef cattle.

Behavioral observations are important to detect illness in beef cattle. However, traditional observation techniques are time and labor intensive and may be subjective. The objective was to validate a system for monitoring individual feeding behavior and activity in beef cattle (Fedometer [FEDO]; ENGS, Rosh Pina, Israel). Sixteen steers (initial BW ± SD = 326 ± 46 kg) were fitted with data loggers (FEDO) on their left front leg and housed in a pen with a feedbunk equipped with an antenna emitting an electromagnetic field that reached 30 ± 2 cm in front of the feedbunk. Feedbunk attendance (duration of visit and frequency of meals) measured by FEDO was compared with live observations (27 observational periods lasting between 72 and 240 min; mean 126 min). Lying time and frequency of lying bouts were compared with previously validated accelerometers fitted to the hind leg (10 steers equipped for 10 to 12 d; HOBO Pendant G Acceleration Data Logger [HOBO]; Onset Computer Corporation, Pocasset, MA). Step counts were compared with video recordings (15 observations for 6-min intervals in 6 steers). Concordance correlation coefficients (CCC), accounting for repeated measures, and limits of agreement were computed. Comparison between FEDO and observed time at the feedbunk yielded a CCC of 0.98 (95% confidence interval [CI] 0.97-0.99). All 68 meal events observed were recorded by FEDO. However, FEDO recorded 4 meal events during the 27 observational periods that were not observed. Lying time measured by HOBO and FEDO were highly correlated (CCC = 0.98; 95% CI 0.97-0.99). However, frequency of lying bouts measured by FEDO was only moderately correlated to HOBO (CCC = 0.71; 95% CI 0.63-0.77); FEDO underestimating the number of lying bouts (on average, 0.4 fewer bouts per 6 h). Step count by FEDO was moderately correlated to video observations (CCC = 0.75; 95% CI 0.49-0.89); FEDO overestimating the number of steps (on average, 5 more steps per 6 min). In conclusion, the FEDO system accurately measured duration of feedbunk attendance, frequency of meals, and lying time. However, it overestimated the number of steps and underestimated the frequency of lying bouts.

Evaluation of a Computer-aided Lung Auscultation System for Diagnosis of Bovine Respiratory Disease in Feedlot Cattle.

BACKGROUND: A computer-aided lung auscultation (CALA) system was recently developed to diagnose bovine respiratory disease (BRD) in feedlot cattle. OBJECTIVES: To determine, in a case-control study, the level of agreement between CALA and veterinary lung auscultation and to evaluate the sensitivity (Se) and specificity (Sp) of CALA to diagnose BRD in feedlot cattle. ANIMALS: A total of 561 Angus cross-steers (initial body weight = 246 ± 45 kg) were observed during the first 50 day after entry to a feedlot. METHODS: Case-control study. Steers with visual signs of BRD identified by pen checkers were examined by a veterinarian, including lung auscultation using a conventional stethoscope and CALA that produced a lung score from 1 (normal) to 5 (chronic). For each steer examined for BRD, 1 apparently healthy steer was selected as control and similarly examined. Agreement between CALA and veterinary auscultation was assessed by kappa statistic. CALA's Se and Sp were estimated using Bayesian latent class analysis. RESULTS: Of the 561 steers, 35 were identified with visual signs of BRD and 35 were selected as controls. Comparison of veterinary auscultation and CALA (using a CALA score ≥2 as a cut off) revealed a substantial agreement (kappa = 0.77). Using latent class analysis, CALA had a relatively high Se (92.9%; 95% credible interval [CI] = 0.71-0.99) and Sp (89.6%; 95% CI = 0.64-0.99) for diagnosing BRD compared with pen checking. CONCLUSIONS: CALA had good diagnostic accuracy (albeit with a relatively wide CI). Its use in feedlots could increase the proportion of cattle accurately diagnosed with BRD.